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Everything you need to know about Computed Tomography (CT) & CT Scanning

August 2020 Imaging Pearls - Educational Tools | CT Scanning | CT Imaging | CT Scan Protocols - CTisus
Imaging Pearls ❯ August 2020

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Adrenal

  • “Contemporary ACC predominantly presents as an incidental imaging finding, characterized by HU > 20 on nonenhanced CT but variable tumour size (20–196 mm). Malignancy cannot be ruled out by small tumour size only. The 5- year survival of 96% in ENSAT stage I–III compares favourably to previous studies.”
    Adrenocortical carcinoma: presentation and outcome of a contemporary patient series
    Kostiainen I et al.
    Endocrine (2019) 65:166–174
  • “Previously, 10–15% of ACCs have presented as incidental imaging findings, while reported prevalence of ACC among adrenal incidentalomas has varied between 1–11%. However, incidentally discovered asymptomatic adrenal masses are getting more common due to increasing use of imaging. We hypothesized that presentation and outcome of ACC may differ in modern compared to old series. We here report data on presentation, treatment and outcome in a contemporary series, including all patients from a single centre diagnosed in 2002 to 2018, and nationwide incidence of ACC in 2001–2015.”
    Adrenocortical carcinoma: presentation and outcome of a contemporary patient series
    Iiro Kostiainen I et al.
    Endocrine (2019) 65:166–174
  • “In conclusion, contemporary ACC predominantly presents as an incidental imaging finding, characterized by HU > 20 on nonenhanced CT but variable tumour size (20–196 mm). Malignancy cannot be ruled out by small tumour size only.”
    Adrenocortical carcinoma: presentation and outcome of a contemporary patient series
    Kostiainen I et al.
    Endocrine (2019) 65:166–174
  • “Adrenocortical carcinoma (ACC) is a rare, aggressive tumor arising from the adrenal cortex that typically presents late with a large mass. The increased use of cross-sectional imaging for unrelated reasons has led to a greater number of ACCs being detected incidentally at an earlier stage. Recognition of the typical clinical, biochemical, and imaging findings is imperative for rapid diagnosis, prompt intervention, and early use of the appropriate therapy. Cross-sectional imaging with CT and MRI is essential for determining the extent of local and distant tumor spread.”
    Adrenocortical Carcinoma: The Range of Appearances on CT and MRI
    Nishat Bharwani et al.
    AJR 2011; 196:W706–W714
  • “ACCs account for only 0.05–0.2% of all cancers or 1–2 patients per 1 million population per year. The age distribution of the affected population is bimodal, with an increased incidence in infants and children younger than 5 years old and in individuals in their fourth and fifth decades of life . A female preponderance has been noted, and women are more likely than men to present with more well-differentiated tumors that tend to be functional.”
    Adrenocortical Carcinoma: The Range of Appearances on CT and MRI
    Nishat Bharwani et al.
    AJR 2011; 196:W706–W714
  • Syndromes Associated with Primary Adrenal Carcinoma
    - Li-Fraumeni Cancer Syndrome: Li-Fraumeni cancer syndrome results in a familial susceptibility to a variety of cancers including adrenocortical tumors (carcinomas, adenomas), sarcomas, leukemias, breast, brain, lung, and laryngeal cancers because of a germline TP53 mutation.
    - Carney Complex: Carney complex consists of primary pigmented nodular adrenal dysplasia, cardiac myxomas, cutaneous myxomas, testicular tumors, and other en- docrine neoplasms.
    - Beckwith-Wiedemann syndrome is a congenital disorder characterized by pre- and postnatal overgrowth, macroglossia, and anterior abdominal wall defects (most commonly exomphalos).
  • Syndromes Associated with Primary Adrenal Carcinoma
    - Familial Adenomatous Polyposis Coli: Familial adenomatous polyposis coli causes multiple adenomatous polyps and cancer of the colon and rectum, thyroid tumors, hepatoblastoma, and adrenocortical tumors (carcinomas, adenomas).
    - Multiple Endocrine Neoplasia, Type 1: Multiple endocrine neoplasia, type 1, causes pituitary, parathyroid, and pancreatic tumors; adrenocortical adenomas or hyperplasia; and, very rarely, adrenocortical carcinomas.
  • “ACCs are functional in approximately 60% of cases ,more commonly in children (? 85%) than in adults (15–30%). Unlike adrenal adenomas that predominantly secrete cortisol, ACCs secrete a variety of hormones including androgens, cortisol, estrogens, and aldosterone. In adult patients with functioning tumors, 30% present with Cushing syndrome, 20% with virilization, and 10–20% with a combination of the two. Feminization and hyperaldosteronism are much rarer, each accounting for approximately 2% of ACC cases.”
    Adrenocortical Carcinoma: The Range of Appearances on CT and MRI
    Nishat Bharwani et al.
    AJR 2011; 196:W706–W714
  • “Approximately 65–85% of ACCs in adults are nonfunctioning, and patients present with a large mass and symptoms related to mass effect (e.g., abdominal or flank pain in 55%) [7] or with a palpable mass (40–50%) [1, 7]. Some ACCs are discovered incidentally (0–25%) when they tend to be smaller.”
    Adrenocortical Carcinoma: The Range of Appearances on CT and MRI
    Nishat Bharwani et al.
    AJR 2011; 196:W706–W714
  • “Calcification, either microcalcification or coarse calcification, is seen on CT in approximately 30% of patients with ACC and is usually centrally located. Calcification is rare in adenomas, although it is present in approximately 10% of pheochromocytomas.”
    Adrenocortical Carcinoma: The Range of Appearances on CT and MRI
    Nishat Bharwani et al.
    AJR 2011; 196:W706–W714
  • “Metastases are frequently found at presentation: Regional and paraaortic lymph nodes (25–46%), lungs (45–97%), liver (48–96%), and bone (11–33%) are the common sites. Hepatic metastases tend to be hypervascular and are best seen on arterial phase imaging after IV contrast administration. 10% of pheochromocytomas.”
    Adrenocortical Carcinoma: The Range of Appearances on CT and MRI
    Nishat Bharwani et al.
    AJR 2011; 196:W706–W714
  • “FDG PET can identify some malignant adrenal masses by virtue of their increased metabolic activity; however, when FDG uptake is only modest, the likelihood of benign versus malignant is about equal. FDG PET combined with contrast-enhanced CT has a sensitivity of 100% and specificity of 87–97% for identifying malignant adrenal masses. The lower specificity is because a small number of adenomas and other benign lesions mimic malignancy.”
    Adrenocortical Carcinoma: The Range of Appearances on CT and MRI
    Nishat Bharwani et al.
    AJR 2011; 196:W706–W714
  • “Patients with unresectable stage IV ACC have a median survival of 3 months. When treated aggressively with surgery, patients with stage I and II tumors have an approximately 65% 5-year survival, whereas patients with stage III and IV disease have 40% and 10% 5-year survival, respectively . The overall 5-year survival rate for all patients with ACC is 38%. Recurrence and metastatic lesions mimic malignancy.”
    Adrenocortical Carcinoma: The Range of Appearances on CT and MRI
    Nishat Bharwani et al.
    AJR 2011; 196:W706–W714
  • Primary Adrenal Carcinoma: Differential Diagnosis
    - Large adenoma
    - Pheochromocytoma
    - Lymphoma
    - Metastases
    - Ganglioneuroma
    - Neuroblastoma
  • The causes of Conn syndrome and Cushing syndrome in the adrenal glands
    Cushings Syndrome
    - Adrenal adenoma
    - Adrenocortical carcinoma
    - Pheochromocytoma
    - Primary pigmented nodular adrenocortical disease (PPNAD)
    - Macronodular hyperplasia with marked adrenal enlargement (MHMAE)
  • The causes of Conn syndrome and Cushing syndrome in the adrenal glands
    Conn Syndrome
    - Adrenal adenoma (50-60%)
    - Adrenocortical carcinoma (1%)
    - Adrenal hyperplasia (bilateral idiopathic hyperplasia, primary adrenal hyperplasia)
  • “CS or hypercortisolism is classically described as the signs and symptoms associated with prolonged exposure to pathologically elevated cortisol levels, which represents hypercortisolism stemming from various causes other than a pituitary adenoma. CS can result from exogenous administration of glucocorticoids or endogenous overproduction of cortisol. The triggering pathways of CS can be divided into pituitary-dependent and pituitary-independent. Females are more likely to have CS than males. CS is most commonly caused by adrenal adenomas; other causes include adrenocortical carcinoma (ACC), pheochromocytomas.”
    CT and MRI of adrenal gland pathologies
    Fuqin Wang et al.
    Quant Imaging Med Surg. 2018 Sep; 8(8): 853–875.
  • “Conn syndrome, or primary aldosteronism, which is characterized by excessive spontaneous secretion of aldosterone from the adrenal glands, affects 6% of people with high blood pressure and can be either sporadic or familial. Conn syndrome is related to autonomous aldosterone production causing sodium retention, plasma renin suppression, hypertension, cardiovascular damage, and increased potassium excretion, leading to variable degrees of hypokalemia.”
    CT and MRI of adrenal gland pathologies
    Fuqin Wang et al.
    Quant Imaging Med Surg. 2018 Sep; 8(8): 853–875.
  • "Addison disease, or primary adrenal insufficiency, is a systemic disease caused by hypoadrenocortical hypofunction. Addison disease has many causes, the most common of which is autoimmune adrenalitis, and other causes include tuberculosis, malignant tumor, infection, hemorrhage, HIV and certain genetic conditions. The incidence of Addison disease is 0.6/100,000 of population per year. Patients may experience weight loss, weakness, fatigue, gastrointestinal upset, orthostatic hypotension and pigmentation of skin. Dehydration, shock, hyperkalemia, and hyponatremia occurred in patients with adrenal crisis.”
    CT and MRI of adrenal gland pathologies
    Fuqin Wang et al.
    Quant Imaging Med Surg. 2018 Sep; 8(8): 853–875.
  • Addisons Disease: Causes
    - autoimmune adrenalitis
    - tuberculosis
    - malignant tumor
    - infection,
    - hemorrhage,
    - HIV certain genetic conditions.
  • "Tumors were inhomogeneous at nonenhanced CT, particularly masses larger than 6 cm, owing to the presence of necrosis. After contrast material infusion, adrenocortical carcinoma enhances heterogeneously, often peripherally, with a thin rim of enhancing capsule seen in some cases. Studies of lesion washout have reported that adrenocortical carcinoma typically has an RPW of less than 40%, with specific measures reported in Table 4 .However, the large size and heterogeneity are more reliable indicators of the diagnosis than are washout values, which vary depending on which part of the mass is sampled. In 19%–33% of cases, calcifi- cations have been identified, more commonly microcalcifications.”
    Adrenal Mass Imaging with Multidetector CT: Pathologic Conditions, Pearls, and Pitfalls
    Pamela T. Johnson, MD • Karen M. Horton, MD • Elliot K. Fishman MD
    RadioGraphics 2009; 29:1333–135
  • “Invasion of the IVC is a well-known complication of adrenocortical carcinoma. Patients with IVC involvement may present with hormonal syndromes, constitutional symptoms, abdominal pain, lower extremity edema, or pulmonary embolism. In one series of 15 adrenocortical carcinomas that invaded the IVC, 12 were on the right side. Also presented in that article was a summary of the literature, which revealed that the highest level of venous extension in 51% of patients was the suprahepatic IVC among those for whom this information was provided. When masses arising in the region.”
    Adrenal Mass Imaging with Multidetector CT: Pathologic Conditions, Pearls, and Pitfalls
    Pamela T. Johnson, MD • Karen M. Horton, MD • Elliot K. Fishman MD
    RadioGraphics 2009; 29:1333–135
  • “Cortical carcinoma is an uncommon malignant adrenal tumor, with a bimodal peak of incidence in childhood and middle age. For unclear reasons, it may be functioning especially in females, who also show more frequently an association with endocrine syndromes including Li-Fraumeni syndrome, Beckwith-Wiedemann syndrome, Carney complex, congenital adrenal hyperplasia, and MEN-1. Non-functioning lesions are asymptomatic as long as they become so large to determine compression and dislocation of adjacent structures.”
    Imaging features of adrenal masses
    Albano D et al.
    Insights into Imaging (2019) 10:1
  • “On CT, adrenal carcinoma shows a heterogeneous appearance due to necrosis, calcifications, and hemorrhage. After intravenous contrast injection, it demonstrates heterogeneous and mainly peripheral enhancement [66]. As previously reported, the RPW of the carcinoma tends to be less than 40%. Invasion of adjacent structures such as kidney, inferior vena cava, and splenic vessels are common as well as liver metastasis and retroperitoneal lymph nodal locations.”
    Imaging features of adrenal masses
    Albano D et al.
    Insights into Imaging (2019) 10:1
Cardiac

  • “Behcet's disease (BD) is a chronic inflammatory disorder, with vasculitis underlying the pathophysiology of its multisystemic effects. Venous pathology and thrombotic complications are hallmarks of BD. However, it has been increasingly recognized that cardiac involvement and arterial complications are also important aspects of the course of the disease. Cardiac lesions include pericarditis, endocarditis, intracardiac thrombosis, myocardial infarction, endomyocardial fibrosis, and myocardial aneurysm.”
    Cardiac manifestations in Behcet's disease
    Selami Demirelli et al.
    Intractable Rare Dis Res. 2015 May; 4(2): 70–75.
  • "The morphological basis of the systemic manifestations in BD, including cardiovascular involvement, is vasculitis . More specifically, some pathologists consider perivascular structures as the main target of T lymphocyte-mediated immune reactions, and perivasculitis as an essential part of the vasculopathy in BD. The venous and arterial wall lesions attract cytokinergic and neutrophilic reactions. Activated neutrophils cause destructive effects by excessive production of superoxide anion radicals and lysosomal enzymes. Neutrophilic infiltration and advanced vascular wall destruction with aneurysm formation cause local blood flow abnormalities.”
    Cardiac manifestations in Behcet's disease
    Selami Demirelli et al.
    Intractable Rare Dis Res. 2015 May; 4(2): 70–75.
  • "Coronary aneurysms may be seen during angiography procedures in patients with BD. Some of these aneurysms are asymptomatic, whereas others manifest with acute coronary syndrome. These aneurysms are isolable, and most are evident together with coronary stenosis and are sometimes seen together with several arterial aneurysms.”
    Cardiac manifestations in Behcet's disease
    Selami Demirelli et al.
    Intractable Rare Dis Res. 2015 May; 4(2): 70–75.
  • “Behcet's disease (BD) is a multisystem vasculitis of unknown etiology, characterized by recurrent urogenital ulceration, cutaneous eruptions, uveitis, arthritis and vasculitis. Less commonly, coronary arteries are involved, with potential serious consequences.”
    PREVALENCE AND PREDICTORS OF CORONARY ARTERY DISEASE IN BEHCET'S DISEASE
    Jalaj Garg et al. 
    Journal of the American College of Cardiology
    Volume 63, Issue 12 Supplement, April 2014
Deep Learning

  • Purpose: To enhance clinician’s decision-making by diagnosing hepatocellular carcinoma (HCC) in cirrhotic patients with indeterminate liver nodules using quantitative imaging features extracted from triphasic CT scans.
    Conclusion: A signature using a single feature was validated in a multicenter retrospective cohort to diagnose HCC in cirrhotic patients with indeterminate liver nodules. Artificial intelligence could enhance clinicians’ decision by identifying a subgroup of patients with high HCC risk.
    Radiomics machine-learning signature for diagnosis of hepatocellular carcinoma in cirrhotic patients with indeterminate liver nodules
    Fatima-Zohra Mokrane et al.
    European Radiology (2020) 30:558–570
  • "Our study assembled the largest radiomics dataset of indeterminate cirrhotic liver nodules to date and offers a proof of concept that machine-learning-based radiomics signature using change in quantitative CT features across the arterial and portal venous phases can allow a non-invasive accurate diagnosis of HCCs in cirrhotic patients with indeterminate nodules. This signature would allow for identification of high HCC–risk patients, who should be prioritized for therapy, allowing thus clinically significant benefits.”
    Radiomics machine-learning signature for diagnosis of hepatocellular carcinoma in cirrhotic patients with indeterminate liver nodules
    Fatima-Zohra Mokrane et al.
    European Radiology (2020) 30:558–570
  • Results: The reliability of radiomic features calculated by the different software platforms was only excellent (ICC > 0.9) for 4/17 radiomic features when comparing all four platforms. Reliability improved to ICC > 0.9 for 15/17 radiomic features when analysis was restricted to the three IBSI-compliant platforms. Failure to harmonize calculation settings resulted in poor reliability, even across the IBSI-compliant platforms. Software platform version also had a marked effect on feature reliability in CERR and LIFEx. Features identified as having significant relationship to survival varied between platforms, as did the direction of hazard ratios.
    Conclusion: IBSI compliance, user-defined calculation settings and choice of platform version all influence the statistical reli- ability and corresponding performance of prognostic models in radiomics.
    Reliability and prognostic value of radiomic features are highly dependent on choice of feature extraction platform
    Isabella Fornacon-Wood et al.
    European Radiology https://doi.org/10.1007/s0330-020-06957-9
  • • Reliability of radiomic features varies between feature calculation platforms and with choice of software version.
    • Image Biomarker Standardisation Initiative (IBSI) compliance improves reliability of radiomic features across platforms, but only when calculation settings are harmonised.
    • IBSI compliance, user-defined calculation settings and choice of platform version collectively affect the prognostic value of features.
    Reliability and prognostic value of radiomic features are highly dependent on choice of feature extraction platform
    Isabella Fornacon-Wood et al.
    European Radiology https://doi.org/10.1007/s0330-020-06957-9 
  • “The broad application of artificial intelligence techniques in medicine is currently hindered by limited dataset availability for algorithm training and validation, due to the absence of standardized electronic medical records, and strict legal and ethical requirements to protect patient privacy. In medical imaging, harmonized data exchange formats such as Digital Imaging and Communication in Medicine and electronic data storage are the standard, partially addressing the first issue, but the requirements for privacy preservation are equally strict. To prevent patient privacy compromise while promoting scientific research on large datasets that aims to improve patient care, the implementation of technical solutions to simultaneously address the demands for data protection and utilization is mandatory. Here we present an overview of current and next-generation methods for federated, secure and privacy-preserving artificial intelligence with a focus on medical imaging applications, alongside potential attack vectors and future prospects in medical imaging and beyond.”
    Secure, privacy-preserving and federated machine learning in medical imaging
    Georgios A. Kaissis et al.
    Nature Machine Intelligence
    Nat Mach Intell 2, 305–311 (2020). 
  • "We believe that the widespread adoption of secure and private AI will require targeted multi-disciplinary research and investment in the following areas. Decentralized data storage and federated learning systems, replacing the current paradigm of data sharing and centralized storage, have the greatest potential to enable privacy-preserving cross-institutional research in a breadth of biomedical disciplines in the near future, with results in medical imaging and genomics recently demonstrated.”
    Secure, privacy-preserving and federated machine learning in medical imaging
    Georgios A. Kaissis et al.
    Nature Machine Intelligence
    Nat Mach Intell 2, 305–311 (2020). 

  • Secure, privacy-preserving and federated machine learning in medical imaging
    Georgios A. Kaissis et al.
    Nature Machine Intelligence Nat Mach Intell 2, 305–311 (2020). 
  • “Brain tumors are the most prominent neurologically malignant cancers with the highest injury and death rates worldwide. Glioma classification is crucial for the prognosis, assessment of prognostication and the planning of clinical guidelines before surgery. Herein, we introduce a novel stationary wavelet-based radiomics approach to classify the grade of glioma more accurately and in a non-invasive manner. The training dataset of Brain Tumor Segmentation (BraTS) Challenge 2018 is used for performance evaluation and calculation is done based on the radiomics features for three different regions of interest. The classifier, Random Forest, is trained on these features and predicted the grade of glioma. At last, the performance is val- idated by using five-fold cross-validation scheme. The state-of-the-art performance is achieved considering metric ⟨Acc, Sens, Spec, Score, MCC , AUC ⟩ ≡ ⟨97.54%, 97.62%, 97.33%, 98.3%, 94.12%, 97.48%⟩ with machine learning predictive model Random Forest (RF) for brain tumor patients’ classification. Considering the importance of glioma classification for the assessment of prognosis, our approach could be useful in the planning of clinical guidelines prior to surgery.”
    CGHF: A Computational Decision Support System for Glioma Classification Using Hybrid Radiomics- and Stationary Wavelet-Based Features
    Kumar R et al.
    IEEE Access Digital Object Identifier 10.1109/ACCESS.2020.2989193
  • In the proposed work, CGHF, a computationally efficient decision support system based on machine predictive model Random Forest is proposed for gliomas grading. The model is used to predict the instances in HGG or LGG category. The proposed system, CGHF, utilized the filters for radiomics feature extraction and several effective feature selection tech- niques over publicly available BraTS 2018 dataset and train the RF model for classification task. The LS and RFA are best feature selection methods for RF using R-, S- and RS-Extraction methods and ANOVA is second best, stable and suitable method for the proposed system, CGHF. As a future perspective, the multi-class classification of graded gliomas can be considered for prediction of brain tumors.
    CGHF: A Computational Decision Support System for Glioma Classification Using Hybrid Radiomics- and Stationary Wavelet-Based Features
    Kumar R et al.
    IEEE Access Digital Object Identifier 10.1109/ACCESS.2020.2989193
Kidney

  • Oncocytic Neoplasms: Facts
    - Fairly common diagnosis (9% of SRMs)
    - No technique to differentiate oncocytic RCC from oncocytoma with 100% reliability from imaging or biopsy
    - Hybrid tumors: oncocytoma and RCC coexist in one tumor in up to 17% of “oncocytomas”
  • “The etiology of fibromuscular dysplasia (FMD) remains largely unknown. It is well recognized that the incidence is higher in women and the most common clinical presentation is hypertension. It is estimated that the incidence in the general population is 2% to 3%.”
    Renal Artery Fibromuscular Dysplasia in 2640 Renal Donor Subjects: A CT Angiographic Analysis
    McKenzie GA et al.
    J Vasc Interv Radiol. 2013 October ; 24(10): 1477–1480.
  • “Abnormalities including beading, aneurysm, dissection, and stenosis/occlusion were noted in aortic, renal, mesenteric, and iliac distributions. The most commonly affected vessels were the renal arteries (n = 76 [67%]), followed by the lower extremity/iliac arteries (n = 37 [32%]). Aortic abnormalities were less frequently encountered (n = 3 [3%]), including 1 case with mild dilation (4.2 cm) of the ascending aorta and 2 cases of dissection involving the descending aorta, 1 with mild dilation (4.4 cm). Reformatted images were crucial, affecting final assessment in 56% of cases evaluated by reader 1 and 36% evaluated by reader 2.”
    Screening CT Angiography of the Aorta, Visceral Branch Vessels, and Pelvic Arteries in Fibromuscular Dysplasia.
    Bolen M et al
    JACC Cardiovasc Imaging. 2017 May;10(5):554-561
  • "Fibromuscular dysplasia (FMD) is a vascular disease that may result in stenosis, dissection, or aneurysm of nearly all arterial distributions, with the renal and extracranial carotid and vertebral arteries most commonly affected (1). Medium-sized arteries are typically affected, and the disease often involves multiple vascular territories within an individual patient. The etiology of this disease is unclear. It is believed to be neither an inflammatory nor an atherosclerotic process, but genetic and environmental risk factors may play a role in the condition.”
    Screening CT Angiography of the Aorta, Visceral Branch Vessels, and Pelvic Arteries in Fibromuscular Dysplasia.
    Bolen M et al
    JACC Cardiovasc Imaging. 2017 May;10(5):554-561
  • “FMD is a diffuse arteriopathy that involves medium-sized arteries in multiple vascular territories throughout the body, most commonly the renal and cerebrovascular arteries. A high prevalence of arterial aneurysm and dissection has been previously demonstrated among patients with FMD. Use of a specialized screening CTA protocol of the chest, abdomen, and pelvis in a single-center group of patients with FMD diagnosis provided important incremental information about aortic branch vessels; however, aortic abnormalities were uncommon in this group (3%). Reformatted images had a significant effect on final interpretations.”
    Screening CT Angiography of the Aorta, Visceral Branch Vessels, and Pelvic Arteries in Fibromuscular Dysplasia.
    Bolen M et al
    JACC Cardiovasc Imaging. 2017 May;10(5):554-561
  • “There are three types of FMD: intimal, medial, and adventitial. The majority of the FMD is the medial form typically described as the classic “string of beads sign” that has been observed in 65% to 90% of FMD lesions. The string of beads finding is easily detected using CTA. Several studies have compared DSA and CTA for detection of renal artery stenosis (RAS) and have showed slightly lower sensitivities and specificities for CTA ranging from 88% to 100% and 97% to 99%, respectively.”
    Renal Artery Fibromuscular Dysplasia in 2640 Renal Donor Subjects: A CT Angiographic Analysis
    McKenzie GA et al.
    J Vasc Interv Radiol. 2013 October ; 24(10): 1477–1480.
  • Renal oncocytoma is a benign (noncancerous) growth of the kidney. They generally do not cause any signs or symptoms and are often discovered incidentally (by chance) while a person is undergoing diagnostic imaging for other conditions. Some people with renal oncocytoma will have abdominal or flank pain; blood in the urine; and/or an abdominal mass. Although these tumors can occur in people of all ages, they most commonly develop in men who are over age 50.
    NIH-Genetic and Rare Disease Information Center
  • The exact underlying cause of most isolated (single tumor affecting one kidney) renal oncocytomas is unknown; however, multiple and bilateral (affecting both kidneys) renal oncocytomas sometimes occur in people with certain genetic syndromes such as tuberous sclerosis complex and Birt-Hogg-Dube syndrome. Although many benign tumors do not require treatment unless they are causing unpleasant symptoms, it can be difficult to confidently differentiate a renal oncocytoma from renal cell carcinoma. Most affected people are, therefore, treated with surgery which allows for confirmation of the diagnosis.
    NIH-Genetic and Rare Disease Information Center
  • “Metastases to the kidney are a rare entity. Survival appears to be longer in patients who are candidates for and are treated with surgery. Surgical intervention in carefully selected patients with oligometastatic disease and good performance status should be considered. A multidisciplinary approach with input from urologists, oncologists, radiologists and pathologists is needed to achieve the optimum outcomes for this specific patient population.”
    Metastases to the kidney: a comprehensive analysis of 151 patients from a tertiary referral centre
    Cathy Zhou et al.
    BJU Int 2016; 117: 775–782
  • “We found that the most common primary tumours in descending order were lung, colorectal, head and neck and breast/soft tissue/thyroid. This is consistent with historical reports noting the lung as the most prevalent source of metastases, followed by a combination of colorectal, stomach and breast malignancies .Over half of the patients in our cohort were asymptomatic.”
    Metastases to the kidney: a comprehensive analysis of 151 patients from a tertiary referral centre
    Cathy Zhou et al.
    BJU Int 2016; 117: 775–782
  • “In conclusion, metastases to the kidney are still a rare entity. These are typically bronchogenic in nature, solitary and asymptomatic. Diagnostic concordance between radiologist and clinician was lower than expected. Thus, a high index of suspicion and a careful review of the scans by all involved physicians is necessary in the patient with a non-renal malignancy who presents with a suspicious renal mass on imaging. Since renal metastases appear early in the metastatic process and survival appears to be longer in patients treated with surgery, surgical intervention in carefully selected patients with oligometastatic disease and good performance status should be considered.”
    Metastases to the kidney: a comprehensive analysis of 151 patients from a tertiary referral centre
    Cathy Zhou et al.
    BJU Int 2016; 117: 775–782
  • “Renal involvement in lymphoma commonly occurs in the presence of widespread nodal or extranodal lymphoma and is classified as secondary renal lymphoma (SRL). However, lymphoma may rarely involve the kidneys alone without evidence of disease elsewhere; then, it is termed “primary renal lymphoma” (PRL).”
    Imaging of Primary and Secondary Renal Lymphoma
    Ganeshan D et al
    AJR 2013; 201:W712–W719
  • “Although the diagnosis of renal lymphoma can be challenging, an awareness of the spectrum of imaging findings can help to differentiate lymphoma from other renal malignancies such as renal cell carcinoma (RCC) and can lead to appropriate recommendations for biopsy. An accurate diagnosis is critical because renal lymphoma is treated by chemotherapy whereas RCC is typically managed by surgery or ablation.”
    Imaging of Primary and Secondary Renal Lymphoma
    Ganeshan D et al
    AJR 2013; 201:W712–W719
  • CT Appearance of Renal Lymphoma
    - Unilateral or bilateral
    - Solitary or multiple masses
    - Nephromegaly without focal mass
    - Renal Lymphoma is typically Hypovascular
    - Infiltration of the kidney and the perirenal space
    - Adenopathy is often bulky
  • “Renal lymphoma usually occurs in the setting of widespread non-Hodgkin lymphoma, typically B-cell type intermediate- and high-grade tumors or American Burkitt lymphoma. In more than one-half of cases, renal or perirenal spread is detected at initial presentation. Involvement by Hodgkin disease is much less common, being seen in less than 1% of patients at presentation.”
    Imaging of renal lymphoma: patterns of disease with pathologic correlation. 
    Sheth S, Ali S, Fishman E.
    Radiographics. 2006;26(4):1151‐1168
  • "Renal lymphoma has a wide variety of manifestations, including multiple lesions, a solitary lesion, direct extension from retroperitoneal adenopathy, preferential involvement of the perinephric space, and diffuse infiltration of one or both kidneys. The renal sinus and collecting system are less frequently affected, except for obstruction caused by retroperitoneal adenopathy. In a large autopsy series of 696 patients with lymphoma, Richmond et al observed multiple renal masses in 61% of cases. A solitary renal nodule and direct invasion from retroperitoneal adenopathy were equally common, being found in 11 kidneys each.”
    Imaging of renal lymphoma: patterns of disease with pathologic correlation.
    Sheth S, Ali S, Fishman E.
    Radiographics. 2006;26(4):1151‐1168
  • Patterns of Renal Lymphoma on CT
    - Multiple masses (unilateral or bilateral)
    - Solitary mass
    - Direct Extension from Retroperitoneal Adenopathy
    - Perinephric Disease
    - Nephromegaly
Liver

  • "Cholangiocarcinoma (CC) is the second most common primary malignant liver tumor in adults, accounting for 10%-25% of primary liver malignancies. CC is more frequently seen in patients with primary sclerosing cholangitis in North America (often seen in conjunction with inflammatory bowel disease) and in patients with parasitic infections in other parts of the world. Additional risk factors include hepatolithiasis, cirrhosis, and diabetes.”
    Imaging and Management of Liver Cancer
    Abdullah O.Alenezi et al.
    Seminars in Ultrasound, CT and MRI
    Volume 41, Issue 2, April 2020, Pages 122-138
  • "Angiosarcoma and epithelioid hemangioendotheliomas are additional primary liver neoplasms which may occur in adult patients. Angiosarcoma arises from endothelial cells and account for only 2% of primary liver malignancies. It is a vascular tumor on cross-sectional imaging and is not easily differentiated from adenoma or HCC. It is associated with remote exposure to polyvinyl, radium, and arsenic and prognosis is poor.”
    Imaging and Management of Liver Cancer
    Abdullah O.Alenezi et al.
    Seminars in Ultrasound, CT and MRI
    Volume 41, Issue 2, April 2020, Pages 122-138
  • “Hepatoblastoma is the most common malignancy of the liver in infants and children. Generally, it is diagnosed in children aged 100 ng/ml) in most children with hepatoblastoma; < 10% have low or normal AFP levels. Generally, hepatoblastomas, which always manifest as a large multinodular expansile mass in the right lobe, are heterogeneously enhanced in the arterial phase with washout in the portal venous phase or delayed phase and demarcate well from the liver parenchyma.”
    Hepatic nodules with arterial phase hyperenhancement and washout on enhanced computed tomography/magnetic resonance imaging: how to avoid pitfalls
    Mimi Tang et al.
    Abdominal Radiology https://doi.org/10.1007/s00261-020-02560-0
  • “Hepatic epithelioid angiomyolipoma (HEAML) is a subtype of hepatic angiomyolipoma with low malignancy rate. Angiomyolipoma is a type of mesenchymal liver tumor composed of adipose tissue, smooth muscle (spindled or epithelioid), and thick-walled blood vessels. The proportions of these three components may vary. The ratio of men to women is nearly 1:5. Most of these tumors are asymptomatic and occur in the absence of liver disease. The common tumor markers are almost all negative.”
    Hepatic nodules with arterial phase hyperenhancement and washout on enhanced computed tomography/magnetic resonance imaging: how to avoid pitfalls
    Mimi Tang et al.
    Abdominal Radiology https://doi.org/10.1007/s00261-020-02560-0 
  • Purpose: To enhance clinician’s decision-making by diagnosing hepatocellular carcinoma (HCC) in cirrhotic patients with indeterminate liver nodules using quantitative imaging features extracted from triphasic CT scans.
    Conclusion: A signature using a single feature was validated in a multicenter retrospective cohort to diagnose HCC in cirrhotic patients with indeterminate liver nodules. Artificial intelligence could enhance clinicians’ decision by identifying a subgroup of patients with high HCC risk.
    Radiomics machine-learning signature for diagnosis of hepatocellular carcinoma in cirrhotic patients with indeterminate liver nodules
    Fatima-Zohra Mokrane et al.
    European Radiology (2020) 30:558–570
  • "Our study assembled the largest radiomics dataset of indeterminate cirrhotic liver nodules to date and offers a proof of concept that machine-learning-based radiomics signature using change in quantitative CT features across the arterial and portal venous phases can allow a non-invasive accurate diagnosis of HCCs in cirrhotic patients with indeterminate nodules. This signature would allow for identification of high HCC–risk patients, who should be prioritized for therapy, allowing thus clinically significant benefits.”
    Radiomics machine-learning signature for diagnosis of hepatocellular carcinoma in cirrhotic patients with indeterminate liver nodules
    Fatima-Zohra Mokrane et al.
    European Radiology (2020) 30:558–570
  • 3D Imaging of Liver Masses
  • “We herein describe the progress of research on 3D visualization, its workflow, current situation, challenges, opportunities, and its capacity to improve clinical decision-making, emphasizing its utility for patients with liver diseases. Current advances in modern imaging technologies have promised a further increase in diagnostic efficacy of liver diseases. For example, complex internal anatomy of the liver and detailed morphological features of liver lesions can be reflected from CT-based 3D models.”
    Consensus recommendations of three‐dimensional visualization for diagnosis and management of liver diseases
    Chihua Fang et al.
    Hepatology International https://doi.org/10.1007/s12072-020-10052-y
  • “A meta-analysis reported that the application of 3D visualization technology in the diagnosis and management of primary hepatocellular carcinoma has significant or extremely significant differences over the control group in terms of intraoperative blood loss, postopera- tive complications, recovery of postoperative liver function, operation time, hospitalization time, and tumor recurrence on short-term follow-up.”
    Consensus recommendations of three‐dimensional visualization for diagnosis and management of liver diseases
    Chihua Fang et al.
    Hepatology International https://doi.org/10.1007/s12072-020-10052-y
  • "However, the acquisition of high-quality CT images and the use of these images for 3D visualization processing lack a unified standard, quality control system, and homogeneity, which might hinder the evaluation of application efficacy in different clinical centers, causing enormous inconvenience to clinical practice and scientific research. Therefore, rigorous operating guidelines and quality control systems need to be established for 3D visualization of liver to develop it to become a mature technology. Herein, we provide recommendations for the research on diagnosis and management of 3D visualization in liver diseases to meet this urgent need in this research field.”
    Consensus recommendations of three‐dimensional visualization for diagnosis and management of liver diseases
    Chihua Fang et al.
    Hepatology International https://doi.org/10.1007/s12072-020-10052-y

  • Consensus recommendations of three‐dimensional visualization for diagnosis and management of liver diseases
    Chihua Fang et al.
    Hepatology International https://doi.org/10.1007/s12072-020-10052-y
  • “Hepatoblastoma is the most common primary malignant liver tumor in children, accounting for approximately two-thirds of liver tumors. It usually arises before 2 years of age, although it can rarely appear in adults . The majority of hepatoblastomas are diagnosed before the age of 5 years. Hepatoblastoma is classified into epithelial type (56–67%) and mixed epithelial and mesenchymal type (33–44%) . The fetal subtype has a better prognosis than the small-cell undifferentiated subtype . Hepatoblastoma can be associated with other conditions such as Gardner syndrome, Beckwith-Weideman syndrome and familial adenomatous polyposis.”
    Imaging of primary malignant tumors in non-cirrhotic liver
    G.Mamone et al.
    Diagn Interv Imaging 2020 Feb 3;S2211-5684
  • "On imaging, hepatoblastoma presents as a multilobulated and well-demarcated mass. Amorphous calcifications are observed in 20–50% of tumors and more common in the mixed form. On dynamic contrast-enhanced CT and MRI, hepatoblastoma demonstrates heterogeneous enhancement, which is more evident in the mixed form, to a lesser degree than the surrounding liver, during both arterial and portal venous/delayed phases. Sometimes, areas of subtle hypervascularization may be present during the arterial phase of enhancement.”
    Imaging of primary malignant tumors in non-cirrhotic liver
    G.Mamone et al.
    Diagn Interv Imaging 2020 Feb 3;S2211-5684
  • “Fibrolamellar hepatocellular carcinoma (FLHCC) is a rare tumor, accounting for less than 1% of primary hepatic malignancies. Clinical and pathological features of FLHCC significantly differ from conventional hepatocellular carcinoma (HCC). Unlike conventional HCC, FLHCC typically develops in young patients less than 40 years of age, without any history of underlying liver disease. Serum alfa-feto proteins are not useful as tumor markers in FLHCC. Imaging plays an important role in diagnosis and staging of FLHCC.”
    Fibrolamellar hepatocellular carcinoma: multiphasic CT features of the primary tumor on pre-therapy CT and pattern of distant metastases. 
    Ganeshan, D., Szklaruk, J., Kaseb, A. et al. 
    Abdom Radiol 43, 3340–3348 (2018).
  • "Central stellate scar within the tumor was present in 73% (24/33). Of the 24 patients with central scar, the presence of radiating septal bands extending to the periphery and central calcification within the scar was seen in 21 patients. Overall, the combination of central stellate scar with central calcifications was seen in 67% of the tumors (21/33). Other studies have reported that central scar may be seen in 20–71% of FLHCC. Similarly, central calcification in FLHCC has been reported in 35–68%.”
    Fibrolamellar hepatocellular carcinoma: multiphasic CT features of the primary tumor on pre-therapy CT and pattern of distant metastases.
    Ganeshan, D., Szklaruk, J., Kaseb, A. et al.
    Abdom Radiol 43, 3340–3348 (2018).
  • "In summary, FLHCC is a rare hepatic tumor which occurs predominantly in young individuals under the age of 40 years, without any predisposing factors such as cirrhosis or hepatitis. On CT, these tend to be large, solitary, and often well-defined lesions. FLHCC typically demonstrates heterogeneous hypervascular enhancement in the arterial phase images and variable enhancement in the portal venous phase. Often, these tumors are hypodense on delayed phase images. Central stellate scar with internal calcifications is a useful imaging feature that may help in the diagnosis.”
    Fibrolamellar hepatocellular carcinoma: multiphasic CT features of the primary tumor on pre-therapy CT and pattern of distant metastases.
    Ganeshan, D., Szklaruk, J., Kaseb, A. et al.
    Abdom Radiol 43, 3340–3348 (2018).
  • Purpose: High mortality rate due to liver cirrhosis has been reported over the globe in the previous years. Early detection of cirrhosis may help in controlling the disease progression toward hepatocellular carcinoma (HCC). The lack of trained CT radiologists and increased patient population delays the diagnosis and further management. This study proposes a computer- aided diagnosis system for detecting cirrhosis and HCC in a very efficient and less time-consuming approach.
    Conclusions: The proposed computer-aided diagnosis system for detecting cirrhosis and hepatocellular carcinoma (HCC) showed promising results and can be used as effective screening l in medical image analysis.
    Computer-aided diagnosis of cirrhosis and hepatocellular carcinoma using multi-phase abdomen CT
    Akash Nayak et al.
    International Journal of Computer Assisted Radiology and Surgery (2019) 14:1341–1352
  • “This study has developed a standalone CAD system with promising results for semi-automated liver segmentation using a novel modified region-growing algorithm in axial CT acquisition, followed by classification of subjects to healthy and diseased using histogram analysis and logistic regression and finally detection of the diseased subjects as cirrhosis or HCC using temporal features extracted using the proposed novel multiphasic analysis of contrast-enhanced CT and SVM classifier.”
    Computer-aided diagnosis of cirrhosis and hepatocellular carcinoma using multi-phase abdomen CT
    Akash Nayak et al.
    International Journal of Computer Assisted Radiology and Surgery (2019) 14:1341–1352
  • “HCC is the most common primary liver malignancy worldwide.It is one of few malignancies in which specific imaging findings alone, without tissue diagnosis, is considered adequate to proceed with further clinical management, including locoregional therapy, surgical resection, and/or liver transplantation.Thus, accurate diagnosis is critical so as to not inappropriately treat patients. This requires synthesis of several key imaging features. Unfortunately, definitive diagnosis of HCC can occasionally be a diagnostic dilemma owing to the occasional overlap of HCC imaging features with additional hepatic lesions such as dysplastic nodules, benign neoplasms, or other malignant neoplasms (which require a different treatment approach).”
    Imaging and Management of Liver Cancer
    Abdullah O.Alenezi et al.
    Seminars in Ultrasound, CT and MRI
    Volume 41, Issue 2, April 2020, Pages 122-138
  • The Surveillance, Epidemiology, and End Results (SEER) Data for Hepatoma
  • The Surveillance, Epidemiology, and End Results (SEER) Data for Hepatoma
  • The Surveillance, Epidemiology, and End Results (SEER) Data for Hepatoma
  • The Surveillance, Epidemiology, and End Results (SEER) Data for Hepatoma
  • The Surveillance, Epidemiology, and End Results (SEER) Data for Hepatoma
  • The Surveillance, Epidemiology, and End Results (SEER) Data for Hepatoma
  • The Surveillance, Epidemiology, and End Results (SEER) Data for Hepatoma
  • “Major risk factors for development of HCC include hepatitis B or cirrhosis caused by chronic hepatitis C infection, excess alcohol intake, and certain metabolic diseases. The result of these risk factors is either repeated incidence or sustained hepatic parenchymal inflammation, which results in progressive fibrosis and cirrhosis. Eventually, via a step-wise progression, there is a transformation from preneoplastic lesions (low-grade dysplastic nodule, high-grade dysplastic nodule) to HCC (well-differentiated HCC, moderately differentiated HCC and finally, an advanced, poorly differentiated HCC).”
    Imaging and Management of Liver Cancer
    Abdullah O.Alenezi et al.
    Seminars in Ultrasound, CT and MRI
    Volume 41, Issue 2, April 2020, Pages 122-138
  • "For imaging diagnosis of HCC, regardless of imaging used, the late arterial phase images are the most critical; an ideal late arterial phase image depicts both hepatic artery and early portal vein contrast opacification, without opacification of the hepatic veins. Arterial phase images acquired too early or too late result in inadequate tumoral enhancement; thus, the major imaging feature (APHE), which is required for imaging diagnosis of HCC, will not be detected.”
    Imaging and Management of Liver Cancer
    Abdullah O.Alenezi et al.
    Seminars in Ultrasound, CT and MRI
    Volume 41, Issue 2, April 2020, Pages 122-138

  • Hepatic nodules with arterial phase hyperenhancement and washout on enhanced computed tomography/magnetic resonance imaging: how to avoid pitfalls
    Mimi Tang et al.
    Abdominal Radiology https://doi.org/10.1007/s00261-020-02560-0
  • “HCC is the most common primary malignant tumors of the liver and typically arises in liver cirrhosis. Nevertheless, approximately 20% of HCCs can arise in patients without cirrhosis. There are many causes that can induce the development of HCC, such as hepatitis B virus infection, exposure to Aflatoxin B1, inherited diseases (hemochromatosis, alpha1-antitrypsin deficiency, type I glycogen storage disease, porphyria), metabolic syndrome, non-alcoholic fatty liver disease including non-alcoholic steatohepatitis (NASH), use of anabolic steroids and hepatocellular adenoma.”
    Imaging of primary malignant tumors in non-cirrhotic liver
    G.Mamone et al.
    Diagn Interv Imaging 2020 Feb 3;S2211-5684
  • "HCC in non-cirrhotic liver often presents as a large solitary mass or dominant mass with peripheral satellite lesions, likely due to the absence of surveillance. Peripheral satellite lesions were present in 24% of patients in the study by Fisher et al. For the same reason, extrahepatic spread of disease, including metastases, is more frequently found in non-cirrhotic patients compared to patients with cirrhosis (20.5% vs. 6.5%, respectively). HCC in non-cirrhotic liver can invade the portal vein or hepatic veins in 15% of patients . Abdominal lymphadenopathy can be found in approximately 20% of non-cirrhotic patients with HCC.”
    Imaging of primary malignant tumors in non-cirrhotic liver
    G.Mamone et al.
    Diagn Interv Imaging 2020 Feb 3;S2211-5684
  • "Fibrolamellar HCC is an uncommon variant of non-cirrhotic HCC (approximately 5%) and occurs in non-cirrhotic liver of young patients between the 2nd and 3rd decades of life. It is more prevalent in Europe and North America compared to Asia and Africa and it accounts for 0.5 to 1% of all cases of liver cancer. Unlike conventional HCC, fibrolamellar HCC has a less aggressive biologic behavior and better prognosis. Tumor markers such as alpha fetoprotein are not elevated in fibrolamellar HCC. Surgical resection is the best therapeutic option and the 5-year survival rate after resection is better than that of conventional HCC.”
    Imaging of primary malignant tumors in non-cirrhotic liver
    G.Mamone et al.
    Diagn Interv Imaging 2020 Feb 3;S2211-5684
  • “On imaging, fibrolamellar HCC appears as a large solitary mass, sometimes multifocal, with sharp and lobulated margins. A central scar is detected in 71–73% of fibrolamellar HCC, often stellate and with radial septae. Calcifications can be found in 67–68% of tumors and may be punctate, nodular or stellate, often involving the central scar. Large areas of hemorrhage are uncommon and fat is usually absent.”
    Imaging of primary malignant tumors in non-cirrhotic liver
    G.Mamone et al.
    Diagn Interv Imaging 2020 Feb 3;S2211-5684
  • "On dynamic contrast-enhanced CT and MRI, fibrolamellar HCC shows heterogeneous hypervascularity during the arterial phase, and iso-hypoattenuation/iso-hypointensity during portal and delayed phases. The central scar is usually hypoattenuating/hypointense during arterial and portal venous phases. Late enhancement of the central scar may be present in 12% of fibrolamellar HCC, in relation to fibrous nature.”
    Imaging of primary malignant tumors in non-cirrhotic liver
    G.Mamone et al.
    Diagn Interv Imaging 2020 Feb 3;S2211-5684
  • “The main differential diagnosis includes FNH, hepatic adenoma and common HCC. However, FNH demonstrates homogeneous arterial enhancement and adenoma often contains areas of hemorrhage or fat, which are usually absent in fibrolamellar HCC. Furthermore, calcifications are rare in FNH and adenoma, the scar in FNH is usually smaller and hyperintense on T2-weighted images and FNH is typically iso-hyperintense on MRI obtained with a hepato-specific contrasts agent. Finally, 65% of fibrolamellar HCC are associated with lymph node metastasis and peritoneal carcinosis is not rare at the time of diagnosis.”
    Imaging of primary malignant tumors in non-cirrhotic liver
    G.Mamone et al.
    Diagn Interv Imaging 2020 Feb 3;S2211-5684
  • “Here, the role of imaging is to differentiate HCC from several non- malignant cirrhosis-associated nodules (e.g., regenerative, low and high-grade dysplastic nodules), benign lesions or pseudo lesions that may be encountered in the cirrhotic liver (e.g., hemangiomas, focal or confluent fibrosis, transient per- fusion disorders), as well as other malignant lesions such as intrahepatic cholangiocarcinoma (ICC). Like most other solid tumors, HCC presents with variable imaging features corresponding to a wide spectrum of pathological and biological characteristics.”
    Hepatocellular Carcinoma: Current Imaging Modalities for Diagnosis and Prognosis
    Maxime Ronot - Yvonne Purcell - Valérie Vilgrain
    Digestive Diseases and Sciences (2019) 64:934–950
  • "Early HCC can be considered the equivalent of “carcinoma in situ” or “micro-invasive carcinoma” and therefore a transitional tumor between preneoplastic lesions and overt or advanced HCC. Compared to overt HCC, early HCCs are usually smaller (< 1.5 cm), vaguely nodular with ill-defined margins, and lack a peripheral capsule. They correspond to well-differentiated lesions.”
    Hepatocellular Carcinoma: Current Imaging Modalities for Diagnosis and Prognosis
    Maxime Ronot - Yvonne Purcell - Valérie Vilgrain
    Digestive Diseases and Sciences (2019) 64:934–950
  • “As previously stated, the hallmarks of HCC are the association of non-rim arterial phase hyperenhancement and washout on the portal venous and/or delayed phases. Historically, arterial phase hyperenhancement corresponds to the first imaging feature described in HCC. However, it is not specific alone and may also be observed in benign lesions, focal perfusion disorders, arterio-portal shunts, non-HCC malignancies such as intrahepatic cholangiocarcinoma, and more rarely in other cirrhosis-associated nodules such as high-grade dysplastic nodules. Therefore, washout has been used to increase the specificity of the diagnosis of HCC on imaging.”
    Hepatocellular Carcinoma: Current Imaging Modalities for Diagnosis and Prognosis
    Maxime Ronot - Yvonne Purcell - Valérie Vilgrain
    Digestive Diseases and Sciences (2019) 64:934–950
  • "It is important to note that around 40% of HCCs lack arterial phase enhancement. These mainly correspond to early HCCs or poorly differentiated infiltrative HCCs. Moreover, 40–60% of small HCCs do not exhibit washout during the venous phases. Arterial phase hyperenhancement must not be predominantly peripheral (hence the term “non-rim”) because this appearance favors the diagnosis of other malignancies such as cholangiocarcinoma.”
    Hepatocellular Carcinoma: Current Imaging Modalities for Diagnosis and Prognosis
    Maxime Ronot - Yvonne Purcell - Valérie Vilgrain
    Digestive Diseases and Sciences (2019) 64:934–950
  • "The capsule corresponds to a peripheral rim of hyperenhancement during the portal venous or delayed phase . Studies of resected HCCs have shown that the image of capsule on CT or MRI is correlated with the presence of a tumor capsule at pathology. However, the presence of a capsule at imaging may also correspond to a “pseudocapsule” including mixed fibrous tissue and dilated sinusoids. Nevertheless, a capsule image has been shown to be an important predictor of HCC. The added value of this finding is weak because most encapsulated HCCs have the typical hallmarks.”
    Hepatocellular Carcinoma: Current Imaging Modalities for Diagnosis and Prognosis
    Maxime Ronot - Yvonne Purcell - Valérie Vilgrain
    Digestive Diseases and Sciences (2019) 64:934–950
  • Detection of Hepatoma In The Cirrhotic Liver
    - CT
    - MR
    - Ultrasound
    - Artificial Intelligence (AI)
  • Purpose: To assess guideline compliance and quality of hepatocellular carcinoma, (HCC) diagnostic imaging within com- munity hospitals (CH) and their Tertiary referral center (TRC) in a moderately high incidence region.
    Conclusions: Community hospital HCC diagnostic scans significantly lag in critical quality parameters of tumor enhancement, arterial phase timing, perceived image quality, and LI-RADS CT technique compliance compared to a TRC.
    Diagnostic imaging of hepatocellular carcinoma at community hospitals and their tertiary referral center in the era of LI‐RADS: a quality assessment study
    Andrew Chan et al.
    Abdominal Radiology (2019) 44:4028–4036
  • “In conclusion, this study found that a substantial proportion of CH CT scans did not comply with LI-RADS imaging technique recommendations. We recommend that a major systematic effort be initiated in jurisdictions with moderate and high incidence of HCC to translate LI-RADS’ technique-related guidelines into community practice.”
    Diagnostic imaging of hepatocellular carcinoma at community hospitals and their tertiary referral center in the era of LI‐RADS: a quality assessment study
    Andrew Chan et al.
    Abdominal Radiology (2019) 44:4028–4036
  • “In the United States, the incidence of HCC has increased since the 1980s. HCC detection at an early stage through surveillance and curative therapy has considerably improved the 5-year survival. Therefore, medical societies advocate systematic screening and surveillance of target populations at par- ticularly high risk for developing HCC to facilitate early- stage detection.”
    Epidemiology of hepatocellular carcinoma: target population for surveillance and diagnosis
    An Tang et al.
    Abdom Radiol (2018) 43:13–25
  • "Major risk factors for HCC include cirrhosis, chronic infection with hepatitis B virus (HBV) or hepatitis C virus (HCV), alcoholic fatty liver disease, and non-alcoholic fatty liver disease (NAFLD). Additional risk factors for HCC include aflatoxin, family history and genetic factors, obesity, diabetes, smoking, and coinfection with human immunodeficiency virus (HIV).”
    Epidemiology of hepatocellular carcinoma: target population for surveillance and diagnosis
    An Tang et al.
    Abdom Radiol (2018) 43:13–25
  • "HCC is a common cancer and second leading cause of cancer mortality worldwide. The geographic distribution of HCC reflects the distribution of HBV and HCV, which currently are the two major etiologic risk factors worldwide. Regardless of the underlying etiology, hepa- tocarcinogenesis generally takes decades of repetitive liver injury. Cirrhosis is a marker of cumulative liver damage, and its presence places patients at high risk for HCC development.”
    Epidemiology of hepatocellular carcinoma: target population for surveillance and diagnosis
    An Tang et al.
    Abdom Radiol (2018) 43:13–25
  • Risk factors for HCC
    - cirrhosis
    - chronic infection with hepatitis B virus (HBV)
    - hepatitis C virus (HCV)
    - excess alcohol consumption
    - non-alcoholic fatty liver disease
    - family history of HCC
    - obesity
    - type 2 diabetes mellitus
    - smoking
Musculoskeletal

  • “Incidental bone lesions on computed tomography examinations are often encountered. Accurate characterization, narrowing the differential diagnosis, and providing appropriate management for bone lesions can be challenging for the abdominal radiologist. CT evaluation of a bony lesion is based on similar principles of lesion evaluation on radiographs. Bone lesions can be classified as non-aggressive or aggressive lesions with widely accepted radiographic patterns: well defined with sclerotic border, well defined with non-sclerotic border, poorly defined with non-sclerotic border, moth-eaten, and permeative.”
    The incidental bone lesion on computed tomography: management tips for abdominal radiologists. 
    Nguyen, M., Beaulieu, C., Weinstein, S. et al
    Abdom Radiol 42, 1586–1605 (2017)
  • "Benign osteoid lesions or bone-containing lesions in the abdomen and pelvis include bone islands (enostosis) and osteoid osteomas. The pelvis, sacrum, and proximal femurs are common sites for bone islands. Bone islands are not true neoplasms but are foci of cortical bone within cancellous bone. Lesions are sharply marginated with thorny, radiating bony spicules on radiographs and CT. A recent paper that analyzed the CT attenuation values of untreated osteoblastic metastases in comparison with bone islands found that mean and maximum cutoff values of 885 and 1060 H.U., respectively, were highly sensitive and specific in that bone islands had attenuation values above these cutoffs.”
    The incidental bone lesion on computed tomography: management tips for abdominal radiologists.
    Nguyen, M., Beaulieu, C., Weinstein, S. et al
    Abdom Radiol 42, 1586–1605 (2017)
  • “Paget’s disease or osteitis deformans can be incidentally identified on a body CT in patients older than 40 years . Paget’s disease in the pelvis and spine typically involves the osteosclerotic phase leading to cortical thickening, enlargement of bone, and coarsened trabeculae. In the vertebral body, these changes produce the “picture frame” vertebral body. The bony changes frequently involve the hemipelvis with thickening of the iliopubic and ilioischial lines and coarsened trabeculae.”
    The incidental bone lesion on computed tomography: management tips for abdominal radiologists. 
    Nguyen, M., Beaulieu, C., Weinstein, S. et al
    Abdom Radiol 42, 1586–1605 (2017)
  • “For solitary lesions with non-sclerotic borders, poorly defined margins, or a permeative or moth-eaten appearance, further imaging work-up and final pathologic diagnosis is recommended. The differentiation between a benign versus malignant lesion may not be possible on CT and may require further imaging with MRI, bone scintigraphy or PET/CT. Any frank bony destructive change indicates a more aggressive process and warrants a final diagnosis. For patients older than 40 year of age, malignant neoplastic lesions such as metastatic disease, multiple myeloma, sarcoma, and lymphoma should be on the differential diagnosis for aggressive bony lesions.”
    The incidental bone lesion on computed tomography: management tips for abdominal radiologists. 
    Nguyen, M., Beaulieu, C., Weinstein, S. et al
    Abdom Radiol 42, 1586–1605 (2017)
  • "Evaluation for bony abnormalities tends to be under-emphasized in the interpretation of abdominal and pelvic CT studies: yet focal lesions are common and their classification has important implications for cancer staging and the need for subsequent imaging or biopsy. When an incidental bony lesion is encountered on CT, the same analysis principles as those used for plain radiographs should be employed. Incidental, well-defined sclerotic lesions are highly likely to be benign. Incidental osteochondromatous and chondroid lesions are usually benign unless there is significant endosteal scalloping/cortical erosion or thick cartilage cap. Destructive bony changes or multifocal lytic lesions typically warrant a final diagnosis.”
    The incidental bone lesion on computed tomography: management tips for abdominal radiologists.
    Nguyen, M., Beaulieu, C., Weinstein, S. et al
    Abdom Radiol 42, 1586–1605 (2017)
Neuroradiology

  • “Brain tumors are the most prominent neurologically malignant cancers with the highest injury and death rates worldwide. Glioma classification is crucial for the prognosis, assessment of prognostication and the planning of clinical guidelines before surgery. Herein, we introduce a novel stationary wavelet-based radiomics approach to classify the grade of glioma more accurately and in a non-invasive manner. The training dataset of Brain Tumor Segmentation (BraTS) Challenge 2018 is used for performance evaluation and calculation is done based on the radiomics features for three different regions of interest. The classifier, Random Forest, is trained on these features and predicted the grade of glioma. At last, the performance is val- idated by using five-fold cross-validation scheme. The state-of-the-art performance is achieved considering metric ⟨Acc, Sens, Spec, Score, MCC , AUC ⟩ ≡ ⟨97.54%, 97.62%, 97.33%, 98.3%, 94.12%, 97.48%⟩ with machine learning predictive model Random Forest (RF) for brain tumor patients’ classification. Considering the importance of glioma classification for the assessment of prognosis, our approach could be useful in the planning of clinical guidelines prior to surgery.”
    CGHF: A Computational Decision Support System for Glioma Classification Using Hybrid Radiomics- and Stationary Wavelet-Based Features
    Kumar R et al.
    IEEE Access Digital Object Identifier 10.1109/ACCESS.2020.2989193
  • In the proposed work, CGHF, a computationally efficient decision support system based on machine predictive model Random Forest is proposed for gliomas grading. The model is used to predict the instances in HGG or LGG category. The proposed system, CGHF, utilized the filters for radiomics feature extraction and several effective feature selection tech- niques over publicly available BraTS 2018 dataset and train the RF model for classification task. The LS and RFA are best feature selection methods for RF using R-, S- and RS-Extraction methods and ANOVA is second best, stable and suitable method for the proposed system, CGHF. As a future perspective, the multi-class classification of graded gliomas can be considered for prediction of brain tumors.
    CGHF: A Computational Decision Support System for Glioma Classification Using Hybrid Radiomics- and Stationary Wavelet-Based Features
    Kumar R et al.
    IEEE Access Digital Object Identifier 10.1109/ACCESS.2020.2989193
Pancreas

  • Background: Solid-pseudopapillary neoplasms (SPNs) are rare pancreatic tumors with malignant potential. Clinicopathologic characteristics and outcomes of patients with SPN were reviewed.
    Study Design: Long-term outcomes were evaluated in patients with an SPN who were followed from 1970 to 2008.
    Conclusions: SPNs are rare neoplasms with malignant potential found primarily in young women. Formal surgical resection may be performed safely and is associated with long-term survival.
    Reddy, S., Cameron, J. L., Scudiere, J., Hruban, R. H., Fishman, E. K., Ahuja, N., Pawlik, T. M., Edil, B. H., Schulick, R. D., & Wolfgang, C. L. (2009).
    Surgical management of solid-pseudopapillary neoplasms of the pancreas (Franz or Hamoudi tumors): a large single-institutional series. 
    Journal of the American College of Surgeons, 208(5), 950–959.
  • Thirty-seven patients were identified with an SPN. Thirty-three (89%) were women, and median age at diagnosis was 32 years. Most patients were symptomatic; the most common symptom was abdominal pain (81%). Thirty-six patients underwent resection; one patient with distant metastases was not operated on. There were no 30-day mortalities. Median tumor size was 4.5 cm. Thirty-four patients underwent an R0 resection, 1 had an R1 resection, and 1 had an R2 resection. Two patients had lymph node metastases, and one patient had perineural invasion. After resection, 34 (94%) patients remain alive. One patient died of unknown causes 9.4 years after resection, and another died of unrelated causes 25.6 years after operation. The patient with widespread disease who didn’t have resection died 11 months after diagnosis. Thirty-five of the 36 patients having resection remained disease free, including those who died of unrelated causes (median followup, 4.8 years). One patient developed a recurrence 7.7 years after complete resection. She was treated with gemcitabine and remains alive 13.6 months after recurrence.
    Reddy, S., Cameron, J. L., Scudiere, J., Hruban, R. H., Fishman, E. K., Ahuja, N., Pawlik, T. M., Edil, B. H., Schulick, R. D., & Wolfgang, C. L. (2009).
    Surgical management of solid-pseudopapillary neoplasms of the pancreas (Franz or Hamoudi tumors): a large single-institutional series. 
    Journal of the American College of Surgeons, 208(5), 950–959.
  • “Solid-pseudopapillary neoplasms (SPNs) of the pancreas are rare neoplasms, comprising only 1% to 2% of all pancreatic tumors. There is a strong female preponderance, and most SPNs present in the third and fourth decade of life. The first published description of an SPN was by Frantz in 1959. This report consisted of a pathologic description of three patients with SPN. Hamoudi and colleagues added an additional patient to the literature in 1970 and detailed the electron microscopic appearance of the tumor. The first report in the surgical literature of an SPN was by Sanfey and associates in 1983.SPNs are also called solid and papillary tumors, papillary cystic tumors, solid cystic tumors, Frantz tumors, and Hamoudi tumors. SPN is synonymous with the preceding names and is the preferred terminology.”
    Reddy, S., Cameron, J. L., Scudiere, J., Hruban, R. H., Fishman, E. K., Ahuja, N., Pawlik, T. M., Edil, B. H., Schulick, R. D., & Wolfgang, C. L. (2009).
    Surgical management of solid-pseudopapillary neoplasms of the pancreas (Franz or Hamoudi tumors): a large single-institutional series. 
    Journal of the American College of Surgeons, 208(5), 950–959.
  • Overview
    - Lymphoepithelial pancreatic cysts are rare lesions of unknown etiology
    - First described in 1985
    - Can occur anywhere in the pancreas
    - Lined by kertanizing squamous epithelium
    - Lymphoid tissue with germinal centers surrounds epithelial lining
    - Contain keratinous debris and cholesterol clefts
  • CLINICAL FINDINGS
    - Predominantly in men (M/F: 4/1)
    - Predominantly in adulthood (mean age=56 and range=26 to 74 years)
    - Often discovered incidentally
    - May be associated with nonspecific abdominal symptoms
    - May be multilocular (53%), bilocular, or unilocular (38%)
    - Range in size from 2 to 13 cm
  • DIFFERENTIAL DIAGNOSIS
    - Pancreatic pseudocyst
    - Serous Cystadenoma
    - IPMN
    - Mucinous Cystic Neoplasm
    - Extrapancreatic cysts impinging upon the pancreas
    --- primary splenic cysts
    --- splenic pseudocysts
    --- cystic teratoma
    --- gastrointestinal duplication cyst
    --- mesenteric cyst
  • CT Findings
    - Primarily visualized as a low-attenuation or cystic lesion arising from the pancreas
    - Often appears exophytic
    - May sometimes be misdiagnosed as cysts arising from other organs, such as spleen, kidney or mesentery
    - Often unilocular and thin walled without internal septations or solid components
  • CT Findings
    - CT appearance can be variable and overlap with other cystic neoplasms.
    - Variety of less common findings have been reported:
    --- small solid component
    --- papillary projections
    --- wall calcifications
    --- thin wall enhancement
Small Bowel

  • “Mesenteric cysts are rare, generally benign intra-abdominal lesions with an incidence ranging from 1 in 105,000 to 1 in 250,000 among admitted surgical patients. Mesenteric cysts have a wide range of presentation in terms of size, clinical presentation, etiology, radiological features, and pathological characteristics. In fact, the average size ranges from 2 to 35 cm and, thus, patients present with nonspecific complaints of abdominal pain, distension, or an abdominal mass.”
    Giant mesenteric cyst: Successful management in low-resource setting
    Antunes M et al
    Int J Surg Case Reports 2020;70:185-187.
  • "Although several classifications have been proposed, the most widely recognized includes 4 groups based on clinical and etiological features: 1) lymphatic, 2) mesothelial, 3) enteric, 4) urogenital, 5) mature cystic teratoma and 6) non pancreatic pseudocysts. In general, simple lymphatic and mesothelial cysts are usually asymptomatic, while lymphangiomas and benign cystic mesotheliomas can be aggressive and invasive. Finally, the only malignant is the malignant cystic mesothelioma.”
    Giant mesenteric cyst: Successful management in low-resource setting
    Antunes M et al
    Int J Surg Case Reports 2020;70:185-187.
  • "Mesenteric cysts are frequently symptomatic and localized in the mesentery but can appear also in adults and middle aged women mainly in retroperitoneal space. The clinical presentation is influenced by the size of the cyst and the age of patients. During childhood, it can simulate an appendicitis, while in adults is often asymptomatic . The symptoms are generally a-specific and include pain, nausea and vomiting, constipation or diarrhea. Moreover, an abdominal palpable mass is present in up to 61% of the patients. Usually, the preoperative diagnosis is done by ultrasound in order to diagnosis.”
    Giant mesenteric cyst: Successful management in low-resource setting
    Antunes M et al
    Int J Surg Case Reports 2020;70:185-187.
  • “Mesenteric cysts are rare, benign intra-abdominal cystic lesions of the gastrointestinal mesentery, with an incidence of 1/100000 in adults and 1/20000 in children, and a female to male ratio of 2:1, which commonly present in the second decade of life. Lesions are most commonly located in the small bowel (66%) and large bowel (33%), with the ascending colon being most frequently affected, and rarely found in the descending colon, sigmoid colon and rectum. They only occasionally extend to the retroperitoneum. The size of a cyst can vary from a few millimetres to 30cm in diameter, containing up to 2500 mL of fluid.”
    Conservative approach to the acute management of a large mesenteric cyst
    Billy C Leung et al.
    World J Clin Cases. 2017 Sep 16; 5(9): 360–363.
  • "Mesenteric cysts are often asymptomatic and discovered as an incidental finding from radiological investigations, but may present with acute or chronic abdominal pain (55%-81%), palpable mass (44%-61%), distension (17%-61%), nausea and vomiting (45%), constipation (27%) and diarrhoea (6%). In severe cases, it can lead to bowel obstruction, obstructive uropathy, volvulus, and peritonitis usually from a haemorrhagic or infective cyst. Surgical excision of the mesenteric cyst, with or without resection of any neighouring visceral organs is the common management approach in the acute setting, with marsupialisation reserved for cases that may require wide resection of adjacent organs, but the recurrence rate is high. Drainage is no longer advised due to infection and recurrence risks.”
    Conservative approach to the acute management of a large mesenteric cyst
    Billy C Leung et al.
    World J Clin Cases. 2017 Sep 16; 5(9): 360–363.
Stomach

  • “MDCT using gaseous and hydro-distension of stomach is an excellent modality for near accurate preoperative T staging of gastric cancer. However, CT has a limited role in the N staging of gastric cancer. This study also suggested that the combined use of virtual gastroscopy and MPR images helps in better detection of early gastric cancers.”
    Preoperative Staging of Gastric Cancer Using Computed Tomography and Its Correlation with Histopathology with Emphasis on Multi-planar Reformations and Virtual Gastroscopy
    Wani AH et al.
    Journal of Gastrointestinal Cancer https://doi.org/10.1007/s12029-020-00436-6
  • Our study suggests that MDCT using gaseous and hydrodistension of stomach is an excellent modality for near accurate preoperative tumor staging of gastric cancer, thereby helping in determining its operability. The addition of CT virtual gastroscopy to multi-planar reformations helps in detection of early gastric cancers. CT has limited role in nodal staging of gastric cancer.”
    Preoperative Staging of Gastric Cancer Using Computed Tomography and Its Correlation with Histopathology with Emphasis on Multi-planar Reformations and Virtual Gastroscopy
    Wani AH et al.
    Journal of Gastrointestinal Cancer https://doi.org/10.1007/s12029-020-00436-6 
Vascular

  • “Behcet's disease (BD) is a chronic inflammatory disorder, with vasculitis underlying the pathophysiology of its multisystemic effects. Venous pathology and thrombotic complications are hallmarks of BD. However, it has been increasingly recognized that cardiac involvement and arterial complications are also important aspects of the course of the disease. Cardiac lesions include pericarditis, endocarditis, intracardiac thrombosis, myocardial infarction, endomyocardial fibrosis, and myocardial aneurysm.”
    Cardiac manifestations in Behcet's disease
    Selami Demirelli et al.
    Intractable Rare Dis Res. 2015 May; 4(2): 70–75.
  • "The morphological basis of the systemic manifestations in BD, including cardiovascular involvement, is vasculitis . More specifically, some pathologists consider perivascular structures as the main target of T lymphocyte-mediated immune reactions, and perivasculitis as an essential part of the vasculopathy in BD. The venous and arterial wall lesions attract cytokinergic and neutrophilic reactions. Activated neutrophils cause destructive effects by excessive production of superoxide anion radicals and lysosomal enzymes. Neutrophilic infiltration and advanced vascular wall destruction with aneurysm formation cause local blood flow abnormalities.”
    Cardiac manifestations in Behcet's disease
    Selami Demirelli et al.
    Intractable Rare Dis Res. 2015 May; 4(2): 70–75.
  • "Coronary aneurysms may be seen during angiography procedures in patients with BD. Some of these aneurysms are asymptomatic, whereas others manifest with acute coronary syndrome. These aneurysms are isolable, and most are evident together with coronary stenosis and are sometimes seen together with several arterial aneurysms.”
    Cardiac manifestations in Behcet's disease
    Selami Demirelli et al.
    Intractable Rare Dis Res. 2015 May; 4(2): 70–75.
  • “Behcet's disease (BD) is a multisystem vasculitis of unknown etiology, characterized by recurrent urogenital ulceration, cutaneous eruptions, uveitis, arthritis and vasculitis. Less commonly, coronary arteries are involved, with potential serious consequences.”
    PREVALENCE AND PREDICTORS OF CORONARY ARTERY DISEASE IN BEHCET'S DISEASE
    Jalaj Garg et al. 
    Journal of the American College of Cardiology
    Volume 63, Issue 12 Supplement, April 2014
  • “TAA is broadly classified into three categories based on cause: (1) degenerative, (2) genetically mediated, and (3) inflammatory (ie, aortitis). Degenerative aneurysms are the most common; are associated with advanced age; occur in the absence of a defined genetic aortopathy or familial clustering; and are associated with cardiovascular risk-factors, such as atherosclerosis and hyper- tension. Genetically mediated TAAs are those that occur in the setting of a known clinical syn- drome (eg, Marfan, Ehlers-Danlos) or in the setting of a genetic mutation in molecular pathways known to be associated with TAA (eg, transform- ing growth factor-b signaling pathway).”
    Imaging Thoracic Aortic Aneurysm
    Kimberly G. Kallianos, Nicholas S. Burris
    Radiol Clin N Am 58 (2020) 721–731
  • “The etiology of fibromuscular dysplasia (FMD) remains largely unknown. It is well recognized that the incidence is higher in women and the most common clinical presentation is hypertension. It is estimated that the incidence in the general population is 2% to 3%.”
    Renal Artery Fibromuscular Dysplasia in 2640 Renal Donor Subjects: A CT Angiographic Analysis
    McKenzie GA et al.
    J Vasc Interv Radiol. 2013 October ; 24(10): 1477–1480.
  • “Abnormalities including beading, aneurysm, dissection, and stenosis/occlusion were noted in aortic, renal, mesenteric, and iliac distributions. The most commonly affected vessels were the renal arteries (n = 76 [67%]), followed by the lower extremity/iliac arteries (n = 37 [32%]). Aortic abnormalities were less frequently encountered (n = 3 [3%]), including 1 case with mild dilation (4.2 cm) of the ascending aorta and 2 cases of dissection involving the descending aorta, 1 with mild dilation (4.4 cm). Reformatted images were crucial, affecting final assessment in 56% of cases evaluated by reader 1 and 36% evaluated by reader 2.”
    Screening CT Angiography of the Aorta, Visceral Branch Vessels, and Pelvic Arteries in Fibromuscular Dysplasia.
    Bolen M et al
    JACC Cardiovasc Imaging. 2017 May;10(5):554-561
  • "Fibromuscular dysplasia (FMD) is a vascular disease that may result in stenosis, dissection, or aneurysm of nearly all arterial distributions, with the renal and extracranial carotid and vertebral arteries most commonly affected (1). Medium-sized arteries are typically affected, and the disease often involves multiple vascular territories within an individual patient. The etiology of this disease is unclear. It is believed to be neither an inflammatory nor an atherosclerotic process, but genetic and environmental risk factors may play a role in the condition.”
    Screening CT Angiography of the Aorta, Visceral Branch Vessels, and Pelvic Arteries in Fibromuscular Dysplasia.
    Bolen M et al
    JACC Cardiovasc Imaging. 2017 May;10(5):554-561
  • “FMD is a diffuse arteriopathy that involves medium-sized arteries in multiple vascular territories throughout the body, most commonly the renal and cerebrovascular arteries. A high prevalence of arterial aneurysm and dissection has been previously demonstrated among patients with FMD. Use of a specialized screening CTA protocol of the chest, abdomen, and pelvis in a single-center group of patients with FMD diagnosis provided important incremental information about aortic branch vessels; however, aortic abnormalities were uncommon in this group (3%). Reformatted images had a significant effect on final interpretations.”
    Screening CT Angiography of the Aorta, Visceral Branch Vessels, and Pelvic Arteries in Fibromuscular Dysplasia.
    Bolen M et al
    JACC Cardiovasc Imaging. 2017 May;10(5):554-561
  • “There are three types of FMD: intimal, medial, and adventitial. The majority of the FMD is the medial form typically described as the classic “string of beads sign” that has been observed in 65% to 90% of FMD lesions. The string of beads finding is easily detected using CTA. Several studies have compared DSA and CTA for detection of renal artery stenosis (RAS) and have showed slightly lower sensitivities and specificities for CTA ranging from 88% to 100% and 97% to 99%, respectively.”
    Renal Artery Fibromuscular Dysplasia in 2640 Renal Donor Subjects: A CT Angiographic Analysis
    McKenzie GA et al.
    J Vasc Interv Radiol. 2013 October ; 24(10): 1477–1480.
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