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Kidney: Renal Artery Imaging Pearls - Educational Tools | CT Scanning | CT Imaging | CT Scan Protocols - CTisus
Imaging Pearls ❯ Kidney ❯ Renal Artery

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  • Renal Artery Aneurysms: Facts
    • Renal artery aneurysms occur with a frequency of less than 1% of the general population.
    • they can be complicated with life-threatening conditions like rupture, thrombosis, embolism, or hypertension. 
    • RAA accounts for 22% of visceral aneurysms
  • Renal Artery Aneurysms: Facts
    • According to a study enrolling adults without renovascular disease, the normal renal artery diameter is approximately 0.5 cm
    • Regarding patients with hypertension, the frequency of the RAA rises to 2.5% and when the hypertension is unresponsive to medical therapy, it can be as high as 39%
  • In general, there are four types of RAAs: the saccular, fusiform, dissecting, and the arteriovenous/microaneurysm (intrarenal) with the saccular being the most frequent one as it accounts for about 70% of all RAAs. Risk factors for the development of an RAA include renal congenital malformations, untreated hypertension, atherosclerosis, trauma, pregnancy, recent surgery, malignancy, angiomyolipoma of the kidney, radiation exposure, and use of drugs like cyclophosphamide 
  • Renal Artery Aneurysm: Complications
    • RAAs usually cause no symptoms but can be complicated by important conditions;
         • rupture,
         • thrombosis,
         • distal embolism,
         • obstructive uropathy,
         • hypertension of renovascular aetiology
         • arteriovenous communications 
  • "RAA should be always included in the differential diagnosis of parapelvic, pararenal masses with rim-like calcification. Even though they can be asymptomatic and incidentally found, they should always be reported and fully investigated. Furthermore, they should always be followed up and under certain indications treated to avoid life-threatening complications."
    Imaging of a Renal Artery Aneurysm Detected Incidentally on Ultrasonography
    Vasileios Rafailidis
    Case Reports in Radiology
    Volume 2014, Article ID 375805
  • Renal Artery Stenosis
    • Majority of renal artery stenosis (90%) is due to atherosclerosis.
    • Risk factors
       - age
       - diabetes
       - aortoiliac occlusive disease
       - hypertension
       - coronary artery disease
  • Fibromuscular Dysplasia: Facts
    • FMD causes less than 10% of renal artery stenosis
    • young or middle aged women
    • associations:
       - smoking
       - hormones
       - vasa vasorum disorders
    • In symptomatic patients, lesions are bilateral in 71%
  • Renal Artery Aneurysm
    • hypertension
    • systemic atherosclerosis
    • extrarenal aneurysms
    • FMD
    • arteritis
    • dissection
    • smoking
    • Marfan syndrome
    • Ehlers-Danlos syndrome
    • Neurofibromatosis
    • aortic coarctation
    • infectious etiologies
  • Renal Artery Aneurysms : Repair
    • All aneurysms > 2 cm
    • Most renal artery aneurysms 1.5 to 2 cm
    • RAA> 1 cm in conjunction with risk factors
       - hypertension
       - ipsi or contralateral renal artery stenosis
       - women of childbearing age
  • Renal Artery Thrombosis: CT Findings
    Axial image from arterial phase CT
    • Elongated filling defect in right renal artery
    • Sharply demarcated cortical hypoenhancement in right kidney secondary to infarct
    • Infarcts are subtle on early CT
  • Renal Artery Stenosis
    • Describe locations
       - atherosclerotic lesions usually arise in the proximal 2 cm or proximal 1/3 of the artery
    • Grade stenosis
    • Characterization of plaque
       - atherosclerotic lesions often calcified
    • Delineation of any secondary findings
  • Renal Artery Aneurysms
    • Usually incidental
    • May be symptomatic pain, hematuria
    • 60% at main artery bifurcation or mainstem artery
    • Bilateral in 19%
    • Multiple in 25-33%
    • ~1/3 of patients have ipsilateral renal artery stenosis
  • Renal Artery Aneurysms : Complications
    • hypertension
    • rupture
    • RA thrombosis
    • infarction by distal embolization
    • AV fistula
  • Renal Artery Aneurysms : Complications
    • Some recommend repair in the setting of pain, or complications, such as dissection or embolization.
    • Endovascular repair has become an alternative treatment option
    • CT can be used to confirm patency following stent-graft occlusion
  • Renal Artery Aneurysms : Complications
    • Risk of rupture increases during pregnancy and correlates with aneurysm size.
    • Surgical treatment
       - decreased blood pressure in 47-60% of those with preoperative hypertension
       - renal function may be improved
  • Renal Artery Dissection
    • Extension from an abdominal aortic dissection
    • Trauma (blunt or iatrogenic)
    • FMD
    • Anti-phospholipid antibody association
    • Ehlers Danlos
    • Idiopathic
  • Renal Artery Thrombosis
    • Thromboembolic disease- cardiac most common
    • Renal Artery insult
       - Spontaneous/traumatic dissection
       - Fibromuscular dysplasia (FMD)
    • Hypercoaguability
       - Antiphospholipid Syndrome
       - Nephrotic Syndrome
  • Renal AVM
    • Rare, congenital malformation
    • May be large (aneurysmal) and solitary or numerous and small (cirsoid type).
       - Cirsoid type more common. 
    • Usually located in renal sinus
    • Usually solitary and right sided
  • Renal AVM: Presentation
    • gross hematuria
    • hypertension
    • flank pain
    • high cardiac output failure
  • “In contradistinction to atherosclerotic stenosis, which are seen in the proximal renal artery, FMD-related stenosis tend to occur in the middle to distal portion of the renal artery.”


    Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “RAAs 1.0–1.5 cm in diameter should be evaluated with surveillance imaging every 1–2 years. Patients with RAAs larger than 1.5 cm should be referred for definitive treatment. Additional indications for treatment of RAAs include uncontrolled hypertension and symptomatic cases due to peripheral vascular bed embolism.”


    Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “The main renal artery normally arises from the abdominal aorta, below the level of the superior mesenteric artery at the L2 vertebral body level. The main renal artery is typically 4–6 cm in length and 5–6 mm in diameter. The right main renal artery is longer and often originates slightly superior to the left renal artery. The right renal artery is the only major vessel to course posterior to the inferior vena cava (IVC).”


    Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “In contrast to accessory renal arteries, which enter the kidney through the hilum, aberrant renal arteries, also known as polar arteries, enter the kidney through the capsule outside the hilum.”


    Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “ Prehilar branches of the main renal artery that arise less than 1.5–2.0 cm from the origin should be noted in patients who are being evaluated as possible renal donors, because these early branches may complicate the surgical arterial anastomosis.”


    Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “The main renal vein usually lies anterior
to the renal artery at the renal hilum. The left renal vein has an average length of 6–10 cm and normally courses anteriorly between the superior mesenteric artery and aorta before emptying into the medial aspect of the IVC. The right renal vein has an average length of 2–4 cm and joins the lateral aspect of the IVC.”


    Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “RAS is the most common cause of secondary hy- pertension and is found in 1%–5% of all patients 
who have hypertension. In greater than two- thirds of cases of RAS, focal narrowing of the renal artery lumen is caused by atherosclerosis. The majority of affected individuals are male and older than 50 years. Atherosclerotic renovascular disease correlates with overall atherosclerotic burden, and the prevalence of this condition is higher among patients with known coronary artery disease.”

    
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “RAS leads to reduced perfusion to the kidney, which then results in systemic hypertension due 
to activation of the renin-angiotensin system . RAS is also an important factor of end-stage renal disease, particularly in persons older than 50 years . RAS caused by atherosclerosis typically occurs at the origin of the renal artery or within the proximal 2 cm of the renal artery. When stenosis 
is detected, careful inspection of the contralateral renal artery is important, as bilateral lesions occur in 30% of cases.”

    
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “Fibromuscular dysplasia (FMD) is a nonath- erosclerotic noninflammatory vascular disease of medium-sized and large arteries that results in focal areas of irregular wall thickening . FMD is the second most common cause of RAS and is found in younger patients, with 
a female-to-male ratio of 9:1. The most commonly affected vessel is the renal artery (in 75% of cases) followed by the internal carotid artery.”

    
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “FMD results in stenosis, aneurysm, dissection, and occlusion of the involved vessels. FMD is subclassi ed into three categories based on the involved arterial layer: medial fibroplasia, which accounts for 80%–90% of cases; intimal fibroplasia, which accounts for 10% of cases; and adventitial fibroplasia, which has an unknown frequency.”


    Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “In contradistinction to atherosclerotic stenosis, which are seen in the proximal renal artery, 
FMD-related stenosis tend to occur in the middle to distal portion of the renal artery. When FMD is discovered in a renal artery, close inspection of the contralateral renal artery is prudent, because FMD occurs bilaterally in two- thirds of patients. Up to 10% of all cases of FMD have associated renal artery aneurysms (RAAs) .”


    Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “The most common subtype, medial fibrobroplasia, is characterized by alternating segments of stenosis and dilatation, which create the “string of pearls” appearance . The intimal medial fibroplasia subtype is characterized by focal long- segment tubular areas of luminal stenosis. CT angiography has been shown to be 100% sensitive for the diagnosis of FMD, and MR angiography is reported to have a sensitivity of 97% and a specificity of 93% for this diagnosis.” 


    Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “However, spontaneous renal artery dissection is a rare entity that occurs without
a known inciting event. Predisposing factors include FMD, malignancy-related hypertension, severe atherosclerosis, Marfan syndrome, Ehlers- Danlos syndrome, subadventitial angioma, cystic medial necrosis, cocaine abuse, and extreme physical exertion.”
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “Aneurysms of the renal artery are true aneurysms caused by degeneration and weakening of the elastic fibers of the arterial wall, with subsequent expansion caused by high intraluminal pressure. The estimated prevalence of RAAs is approximately 0.1%; most of them are detected incidentally in asymptomatic patients. However, patients may present with findings of rupture, thrombosis, or embolism.”

    
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “The management of RAAs is based in part on the size of the aneurysm and the clinical setting; however, size does not have a direct correlation with rupture. RAAs 1.0–1.5 cm in diameter should be evaluated with surveillance imaging every 1–2 years. Patients with RAAs larger than 1.5 cm should be referred for definitive treatment . Additional indications for treatment of RAAs include uncontrolled hypertension and symptomatic cases due to peripheral vascular bed embolism. Pregnant women also are at high risk for RAA rupture.”

    
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “Pseudoaneurysms of the renal artery occur as a result of direct injury to the arterial wall with subsequent disruption and extravasation of the blood contained in the arterial adventitia or surrounding tissues . Pseudoaneurysms occur most often in response to iatrogenic or penetrating trauma . Multiple intraparenchymal pseudoaneurysms can develop with vasculitis and as a result of amphetamine use. A pseudoaneurysm rupture may manifest as hematuria, and pain, and/or hypotensive shock.”


    Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “Vascular abnormalities are found in 0.4%–6.4% of patients with NF-1, and the renal artery is the most commonly involved artery, being affected in 41% of patients with associated vascular abnormalities. Unlike atherosclerotic stenosis, NF-1–associated stenosis often occur in patients younger than 50 years, spare the renal artery origin, are long and tapered, and extend into segmental and intrarenal branches. The stenosis involved with NF-1 are bilateral in 32% of patients. Less commonly, NF-1 manifests with RAAs.”


    Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “Renal arteriovenous malformations (AVMs) are developmental anomalies in which an abnormal connection is present between a renal artery and renal vein owing to a nidus consisting of a network of abnormal vessels. Renal AVMs are usually symp- tomatic; gross hematuria results from the rupture of small venules into calyces that is caused by abnormally increased intravascular pressure. Other symptoms include renovascular hypertension, high-output cardiac failure, and flank pain.”


    Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “An arteriovenous fistula (AVF) is an abnormal direct connection of an artery to a vein without an intervening capillary bed. Most renal AVFs are acquired, and they usually have an iatrogenic cause such as percutaneous nephrostomy or result from penetrating trauma. In up to 18% of cases, AVFs occur after renal biopsy. Idiopathic cases are postulated to occur when an RAA ruptures into an adjacent vein. Most patients are asymptomatic, although they may present with hematuria and flank pain.”

    
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “The nutcracker phenomenon occurs when the left renal vein is compressed between the aorta and superior mesenteric artery and consequently results in left renal vein hypertension. The term nutcracker syndrome refers to the clinical signs and symptoms that can result from this anatomic finding.”


    Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “Nutcracker syndrome is commonly found in thin young females. A history of recent substantial weight loss also is implicated in cases of nutcracker syndrome. Hematuria and and pain are common clinical symptoms. Additional symptoms related to pelvic congestion syndrome also may be present. Compression of the left renal vein can cause left renal vein–to–gonadal vein reflux that results in lower limb varices and varicoceles in males.”


    Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • “Thrombosis that leads to narrowing or occlu- sion of the renal vein can be caused by a bland or tumor thrombus. Patients present with gross hematuria, flank pain, and signs of renal failure. Risk factors of bland renal vein thrombosis include glomerulonephritis, collagen vascular disease, diabetes, and trauma.”

    
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
  • CTA of the Renal Arteries: Classic Clinical Applications
    - Renal donor anatomy
    - UPJ evaluation
    - Renal artery stenosis
    - Fibromuscular dysplasia of the renal arteries
    - Vasculitis involving the renal artery
    - Renal artery aneurysm or pseudoaneurysm
    - AV malformation involving the renal artery
    - Presurgical evaluation including partial nephrectomy planning
  • CTA for Renal Donor Evaluation
    - Renal artery disease was identified in 3.4% of potential donors, including renal artery stenosis, possible fibromuscular dysplasia, and renal artery aneurysm.
    - Significant CT findings also contributed to the selection of the right kidney in 29 donors (of 470 donors), most commonly due to presence of ipsilateral vascular disease or complex left vascular anatomy.
    - Renal parenchymal and vascular abnormalities are common in asymptomatic potential kidney donors. Although most of these represent incidental CT findings, abnormalities can exclude potential renal donors and alter the surgical approach in a small minority of cases

    AJR Am J Roentgenol. 2012 Nov;199(5):1035-41. doi: 10.2214/AJR.11.8058.
  • Renal AV Malformations: Facts
    - Very rare CT findings
    - Usually congenital but may be due to underlying tumor
    - May be large (aneurysmal) and solitary or numerous and small (cirsoid type). Cirsoid type more common.
    - Usually located in renal sinus
    - Usually solitary and right sided
    - Presentation may be gross hematuria, hypertension, flank pain and high cardiac output failure
  • CT of the Renal Artery: Imaging Protocols and Display
    - Arterial phase imaging at 25 seconds post start of injection is usually satisfactory. Triggering acquisition in the upper aorta at 250-300 HU depending of the scanner is also satisfactory
    - Venous or delayed phase imaging may be useful in select applications when function or contrast excretion is needed
    - Dedicated renal artery studies can be done with 80-100 cc of contrast (Omnipaque 350 or Visipaque-320) injected at 4-5 cc/sec
    - Contrast volumes as low as 30-40 cc in patients with decreased renal function can be done with dual energy techniques especially when low kVp (70-80) is available
  • CT of the Renal Artery: Imaging Protocols and Display
    - Scan parameters will vary depending on the specific scanner available but ideally submillimeter slice thickness is used . Our scan parameters are;
    - .75 mm slice thickness from .6 mm collimators
    - 100-120 kVp depending on patient body habitus
    - 180-210 mAs
    - Slices reconstructed at .5 mm intervals
    - Images reconstructed with a soft tissue algorithmn
    - Dual energy imaging with monoenergic selection of 70 kev may be valuable in patients who have comprimised renal function
    - Image display requires analysis using a combination of axial, MPR (coronal, sagital) and 3D (VRT and MIP) imaging is needed
  • CTA of the Normal Renal Arteries
    - Between 70% and 75% of people have one renal artery per kidney, with the remainder being expected to have two or more renal arteries on each side. Renal arteries typically arise at the level of the upper margin of the second lumbar vertebral body, 1 cm below the origin of the superior mesenteric artery. Each renal artery supplies smaller, inferior adrenal arteries, which may be single or multiple.
    - In a study of 400 cadaver donors with 800 kidneys, Pollak et al found that 23% had double renal arteries, 4% had triple arteries, and 1% had quadruple arteries. Multiple renal arteries occur on the left side in 26%–32% of people and on the right side in 23%–29%. Bilateral multiple renal arteries occur in 15%. Higher or lower origins are not uncommon among accessory arteries.
  • “ Identification of renal variants and pathologies is important because it has clinically critical consequences, especially before kidney related procedures such as laparoscopic donor or partial nephrectomy, vascular reconstruction for renal artery stenosis or abdominal aortic aneurysm. MDCT angiography and CE-MR angiography are excellent imaging studies because they are fast and non-invasive and provide highly accurate and detailed evaluation of renal vascular anatomy.”
    Contrast-enhance CT and MRI imaging of renal vessels
    Tuna IS, Tatli S
    Abdom Imaging (2014) 39;875-891
  • “ CT is the modality of choice for patients with pacemakers, automatic implantable cardioverter defibrillator or other non-MR compatible devises. CT also is generally preferred when very high spatial resolution is required or when it is particularly important to demonstrate peripheral arteries (i.e. fibromuscular dysplasia or vasculitis).”
    Contrast-enhance CT and MRI imaging of renal vessels
    Tuna IS, Tatli S
    Abdom Imaging (2014) 39;875-891
  • CTA of the Renal Arteries: Classic Clinical Applications
    - Renal donor anatomy
    - UPJ evaluation
    - Renal artery stenosis
    - Fibromuscular dysplasia of the renal arteries
    - Vasculitis involving the renal artery
    - Renal artery aneurysm or pseudoaneurysm
    - AV malformation involving the renal artery
    - Presurgical evaluation including partial nephrectomy planning
  • CTA for Renal Donor Evaluation
    - Renal artery disease was identified in 3.4% of potential donors, including renal artery stenosis, possible fibromuscular dysplasia, and renal artery aneurysm.
    - Significant CT findings also contributed to the selection of the right kidney in 29 donors (of 470 donors), most commonly due to presence of ipsilateral vascular disease or complex left vascular anatomy.
    - Renal parenchymal and vascular abnormalities are common in asymptomatic potential kidney donors. Although most of these represent incidental CT findings, abnormalities can exclude potential renal donors and alter the surgical approach in a small minority of cases
    - AJR Am J Roentgenol. 2012 Nov;199(5):1035-41. doi: 10.2214/AJR.11.8058.
  • Renal Artery Stenosis: Facts
    - Atherosclerosis is cause in up to 70% of patients
    - Eccentric irregular narrowing is classic and more commonly proximal vessel
    - Decreased renal function and loss of cortex/scarring is common
  • Fibromuscular Dysplasia: Facts
    - Second most common cause of renal hypertension
    - Usually in woman between age 30 and 55
    - Usually occurs in both renal arteries and is in the mid and distal segments of the arteries
    - “string of bead” appearance is most classic with alternating areas of stenosis and dilatation
  • Renal Artery Aneurysm: Etiology
    - Atherosclerosis
    - FMD
    - Neurofibromatosis
    - Polyarteritis nodosa
    - Trauma
    - Intervention common if aneurysm greater than 2 cm or for any size in woman of child bearing age
  • “RAAs are extremely rare clinical entities, which constitute localized dilations of renal arteries and/or branches. RAAs can be classified into 4 basic categories: the saccular, fusiform, dissecting, or intrarenal,and saccular RAA is the most common type.”
    Rupture of Renal Artery Aneurysm: A Rare Urologic Emergency Entity
    Zhou H et al.
    DOI: 10.1016/j.urology.2014.08.002
  • “RAAs are extremely rare clinical entities, which constitute localized dilations of renal arteries and/or branches. RAAs can be classified into 4 basic categories: the saccular, fusiform, dissecting, or intrarenal,and saccular RAA is the most common type.”
    Rupture of Renal Artery Aneurysm: A Rare Urologic Emergency Entity
    Zhou H et al.
    DOI: 10.1016/j.urology.2014.08.002
  • “ Predisposing factors encompass congenital malformations of the kidneys, untreated hypertension, atherosclerosis, pregnancy, trauma, malignancy, renal angiomyolipoma, radiation, and consumption of cyclophosphamide.”
    Rupture of Renal Artery Aneurysm: A Rare Urologic Emergency Entity
    Zhou H et al.
    DOI: 10.1016/j.urology.2014.08.002
  • “There is an increased mortality in type IV EDS, mostly because of vascular complications such as spontaneous arterial rupture, aneurysmal degeneration with subsequent rupture or dissection, and arteriovenous fistulas.”
    Thromboembolic renal infarction due to a renal artery aneurysm in a patient with Ehlers-Danlos syndrome type IV
     Abramowitz Y et al.
    Eur J Vascular Med Vol 17, Issue 5, August 2006, Pages 377–379
  • Renal Artery Dissection: Etiologies
    - Most common cause is extension from an abdominal aortic aneurysm
    - Trauma (blunt or iatrogenic)
    - FMD
    - Anti-phospholipid antibody association
    - idiopathic
  • Renal Artery Thrombosis: Etiologies
    - Trauma
    - Instrumentation
    - Embolism (due to atrial fibrillation, myocardial infarction, rheumatic mitral stenosis)
    - Hypercoagulability states
  • Renal AV Malformations: Facts
    - Very rare CT findings
    - Usually congenital but may be due to underlying tumor
    - May be large (aneurysmal) and solitary or numerous and small (cirsoid type). Cirsoid type more common.
    - Usually located in renal sinus
    - Usually solitary and right sided
    - Presentation may be gross hematuria, hypertension, flank pain and high cardiac output failure
  • “ CTA can be used as part of the preoperative evaluation prior to laparoscopic nephrectomy to provide anatomical information about the presence of multiple renal arteries in the affected kidney of patients with RCC. This could help with planning the surgery and reducing surgical complications.”
    Multiple renal arteries with renal cell carcinoma: preoperative evaluation using computed tomography angiography prior to laparoscopic nephrectomy.
    Guan WH et al.
    J Int Med Res. 2013 Oct;41(5):1705-15. 
  • Renal Artery Dissection: Facts
    - SRAD is postulated as a result of intramural hemorrhage from the vasa vasorum or by penetration of blood into the arterial wall through an intimal tear.1 Several risk factors were associated with SRAD.
    - SRAD has an incidence of 0.05%, with a predilection to affect middle-aged males.
    -  The rarity and nonspecific presentation of SRAD led to diagnostic delay or misdiagnoses.
    - Spontaneous Renal Artery Dissection Complicating With Renal Infarction
    - Tsung-Han Tsai  et al.
    - Urology Vol 76, Issue 6, December 2010, Pages 1371–1372.
  • “RAAs are extremely rare clinical entities, which constitute localized dilations of renal arteries and/or branches. RAAs can be classified into 4 basic categories: the saccular, fusiform, dissecting, or intrarenal,and saccular RAA is the most common type.”
    Rupture of Renal Artery Aneurysm: A Rare Urologic Emergency Entity
    Zhou H et al.
    DOI: 10.1016/j.urology.2014.08.002
  • “ Predisposing factors encompass congenital malformations of the kidneys, untreated hypertension, atherosclerosis, pregnancy, trauma, malignancy, renal angiomyolipoma, radiation, and consumption of cyclophosphamide.”
    Rupture of Renal Artery Aneurysm: A Rare Urologic Emergency Entity
    Zhou H et al.
    DOI: 10.1016/j.urology.2014.08.002
  • “There is an increased mortality in type IV EDS, mostly because of vascular complications such as spontaneous arterial rupture, aneurysmal degeneration with subsequent rupture or dissection, and arteriovenous fistulas.”
    Thromboembolic renal infarction due to a renal artery aneurysm in a patient with Ehlers-Danlos syndrome type IV
    Abramowitz Y et al.
    Eur J Vascular Med Vol 17, Issue 5, August 2006, Pages 377–379
  • CTA of the Renal Arteries: Clinical Applications
    - Renal donor anatomy
    - Renal artery stenosis
    - Fibromuscular dysplasia of the renal arteries
    - Vasculitis involving the renal artery
    - Renal artery aneurysm or pseudoaneurysm
    - AV malformation involving the renal artery
    - Partial nephrectomy planning
  • Normal Renal Artery Anatomy: Facts
    - Length of 4-6 cm
    - Width of 5-6 mm in diameter
    - Multiple renal arteries are seen in up to one-third of patients
    - Bilateral multiple renal arteries are seen in approximately 12% of the population
    - Renal arteries usually arise off the aorta but may arise from the iliac, lumbar, lower thoracic or mesenteric arteries
  • Renal Artery Stenosis: Facts
    - Atherosclerosis is cause in up to 70% of patients
    - Eccentric irregular narrowing is classic and more commonly proximal vessel
    - Decreased renal function and loss of cortex/scarring is common
  • Fibromuscular Dysplasia: Facts
    - Second most common cause of renal hypertension
    - Usually in woman between age 30 and 55
    - Usually occurs in both renal arteries and is in the mid and distal segments of the arteries
    - “string of bead” appearance is most classic with alternating areas of stenosis and dilatation
  • Renal Artery Aneurysm: Etiology
    - Atherosclerosis
    - FMD
    - Neurofibromatosis
    - Polyarteritis nodosa
    - Trauma
    - Intervention common if aneurysm greater than 2 cm or for any size in woman of child bearing age
  • Renal Artery Dissection: Etiologies
    - Most common cause is extension from an abdominal aortic aneurysm
    - Trauma (blunt or iatrogenic)
    - FMD
    - Anti-phospholipid antibody association
    - idiopathic
  • Renal Artery Thrombosis: Etiologies
    - Trauma
    - Instrumentation
    - Embolism (due to atrial fibrillation, myocardial infarction, rheumatic mitral stenosis)
    - Hypercoagulability states
  • Renal Arteries: Miscellaneous Conditions
    - Takayasu’s aortitis
    - Renal artery trauma
    - Tumor encasement by renal cell carcinoma or lymphoma
    - Retroperitoneal process like retroperitoneal fibrosis
  • “ CT is the modality of choice for patients with pacemakers, automatic implantable cardioverter defibrillator or other non-MR compatible devises. CT also is generally preferred when very high spatial resolution is required or when it is particularly important to demonstrate peripheral arteries (i.e. fibromuscular dysplasia or vasculitis).”
    Contrast-enhance CT and MRI imaging of renal vessels
    Tuna IS, Tatli S
    Abdom Imaging (2014) 39;875-891
  • “ Identification of renal variants and pathologies is important because it has clinically critical consequences, especially before kidney related procedures such as laparoscopic donor or partial nephrectomy, vascular reconstruction for renal artery stenosis or abdominal aortic aneurysm. MDCT angiography and CE-MR angiography are excellent imaging studies because they are fast and non-invasive and provide highly accurate and detailed evaluation of renal vascular anatomy.”
    Contrast-enhance CT and MRI imaging of renal vessels
    Tuna IS, Tatli S
    Abdom Imaging (2014) 39;875-891
  • “ More recently, in a study comparing 4-slice MDCT to digital subtraction angiography, the sensitivity and specificity for all degrees of renal artery stenosis were 100% and 98.6%, respectively. For stenosis greater than 50%, sensitivity was 100% and specificity 97.3%.”
    Computed Tomography Angiography of the Renal and Mesenteric Vasculature: Concepts and Applications
    Johnson PT, Fishman EK
    Seminars in Roentgenology
    2011: 115-124
  • Renal Artery Aneurysms: Treatment
    -Surgery for aneurysms over 2 cm in size
    -Stents can be placed in aneurysms especially those under 2 cm
    -Surgery for aneurysms over 1 cm may be indicated with risk factors of hypertension, renal artery stenosis or woman of child bearing age
  • Renal Artery Aneurysms: Facts
    -Most common location is the main renal artery bifurcation or main renal artery (60%)
    -May be multiple in up to 25-33% of patients and may be bilateral in 19% of cases
    -Complications include hypertension, rupture, renal arterial thrombosis, infarction by distal embolization and AV fistula
    -Risk of rupture increases during pregnancy and with increasing aneurysm size
  • Renal Artery Aneurysms: Common Associations
    -Hypertension
    -FMD
    -Atherosclerosis
    -Extrarenal aneurysms
    -Arteritis
    -Marfan’s syndrome
    -Ehlers Danlos syndrome
    -Neurofibromatosis
    -Smoking
  • “ Studies using angiography have revealed that 3.8%-6.6% of potential renal donors have fibromuscular dysplasia (FMD), which was bilateral in 43% to 71%. Atherosclerotic lesions were much less common, identified in 2%.”
    Computed Tomography Angiography of the Renal and Mesenteric Vasculature: Concepts and Applications
    Johnson PT, Fishman EK
    Seminars in Roentgenology
    2011: 115-124
  • CT Angiography of the Renal Arteries: Renal Donor Evaluation
    -Number and location of the renal arteries including presence of prehilar branching
    -Detection of renal artery stenosis  and fibromuscular dysplasia (FMD)
    -Presence of renal mass or other important renal findings (horseshoe kidney, scarring of the kidney)
    -Renal vein and collecting system also evaluated on venous and delayed topogram
  • CT Angiography of the Renal Arteries: Protocols
    -Images reconstructed with narrow collimation (.75 mm) reconstructed at .5 mm intervals
    -All datasets analyze with a combination of axial, multiplanar (coronal and sagittal planes) and 3D rendering (volume rendering (VRT) and maximum intensity projection (MIP))
  • CT Angiography of the Renal Arteries: Protocols
    -Phases required depend on the application with two phases usually necessary
    -Contrast injection rate is 4-5 cc/sec with contrast volumes in the 80-120 cc volume range
    -Contrast used is Omnipaque-350 or Visipaque-320 depending on the patients creatinine or GFR levels
    -Arterial phase imaging is usually with a 25-30 second delay and nephrographic phase is at 55-60 seconds
  • CT Angiography: Renal Applications
    -Renal donor evaluation
    -Renal artery stenosis
    -Renal artery aneurysm
  • Fibromuscular Dysplasia (FMD): Facts

    - Involves mid and distal vessels (not proximal)
    - Results in areas of stenosis and dilatation of small and mid size vessels
    - Cause of hypertension in females under age 40
  • Fibromuscular Dysplasia: Facts

    - Cause of hypertension in younger population
    - More common in woman
    - Most common form is medial fibromuscular disease which occurs in 70% of cases
    - "String of Beads" appearance is classic
  • "Laparoscopic donor nephrectomy has become the accepted method of harvesting the kidney at many institutions because of multiple advantages over open donor nephrectomy. Spiral computed tomographic (CT) angiography provides accurate information of renal vascular anatomy and has become an accepted method of preoperative evaluation of potential laparoscopic renal donors."

    MDCT Angiography of Living Laparoscopic Renal Donors Kawamoto S, Fishman EK
    Abdom Imaging 2006.
  • The Bosniak Renal Cyst Classification System

    - Category I
    - Category II
    - Category IIF
    - Category III
    - Category IV
  • What is a Bosniak IIF?

    - Cysts with multiple septae with minimal thickening or calcification which is thick and nodular or intrarenal non-enhancing high density (>3cm) lesion
    - These lesions are felt to be benign and routine follow-up advised
  • Erdheim-Chester Disease: Facts

    - Rare form of non-Langerhans cell histiocytosis
    - Characterized by tissue infiltration by foamy histiocytes
    - Usually in patients over age 40
    - Can be life threatening
  • Erdheim-Chester Disease: Facts

    - Renal and perirenal involvement in up to 29% of cases
    - May encase the thoracic or abdominal aorta (looks like retroperitoneal fibrosis)
    - Cardiac infiltration may be endocardial, myocardial or pericardial
  • Perinephric Mass: Differential Dx

    - Tumors
    - Fluid
    - Inflammation
    - Proliferative diseases
  • Perinephric Mass: Differential Dx

    - Tumors
    - Renal cell carcinoma
    - Lymphoma
    - Metastases (melanoma)
    - Retroperitoneal tumors by direct extension
  • Perinephric Mass: Differential Dx

    - Fluid
    - Hematoma
    - Urinoma
    - Abscess
    - Pancreatic pseudocyst
  • Perinephric Mass: Differential Dx

    - Proliferative diseases
    - Extramedullary hematopoiesis
    - Retroperitoneal fibrosis
    - Rosai-Dorfman disease
    - Erdheim-Chester disease
  • "In conclusion, multidetector row CT enables highly accurate assessment of the renal anatomy in living donor candidates."

    Assessment of 100 Live Potential renal Donors for Lapatoscopic Nephrectomy with Multidetector Row Helical CT
    Holden A et al.
    Radiology 2005; 237:973-980
  • "Multiple renal arteries were seen in 26% of kidneys. Early branching of the main renal artery was seen in 12% of kidneys."

    Assessment of 100 Live Potential renal Donors for Lapatoscopic Nephrectomy with Multidetector Row Helical CT
    Holden A et al.
    Radiology 2005; 237:973-980
  • "Excretory phase CT with oral hydration opacified the calyx/infundibulum completely in 57% and nearly completely in 38%, opacified the renal pelvis completely in 94.5% and nearly completely in 3.5%, and opacified the upper ureter completely in 78% and completely in 78% and nearly completely in 6.5%."
  • "Excretory phase CT with oral hydration opacified the calyx/infundibulum completely in 57% and nearly completely in 38%, opacified the renal pelvis completely in 94.5% and nearly completely in 3.5%."

    Opacification of the Collecting System and Ureters on Excretory-Phase CT Using Oral Water as Contrast Medium
    Kawamoto S, Horton KM, Fishman EK
    AJR 2006; 186:136-140.
  • "The addition of a saline bolus offers no improvement, whereas the addition of enhanced CT digital radiography offers significant improvement in collecting system opacification during CT urography."

    Opacification of the Genitourinary Collecting System During MDCT Urography with Enhanced CT Digital Radiography: Nonsaline versus Saline Bolus
    Sudakoff GS et al.
    AJR 2006:186:122-129.
  • Transitional Cell Carcinoma: Facts

    - Clinical presentation usually hematuria
    - Account for up to 10% or neoplasms of the kidney
    - Often multifocal
    - Age range is 60-70’s
  • Risk Factors for Contrast Induced Nephrotoxicity

    - Diabetes
    - Preexisting renal insufficiency
    - Dehydration
    - Cardiovascular disease
    - Advanced age
    - Hypertension
    - Hyperuricemia
  • Risk Factors for Contrast Induced Nephrotoxicity

    - Multiple myeloma
    - Certain drug therapies especially chemotherapeutic drugs and long term use of nonsteroidal anti-inflammatory drugs
  • "High risk patients may have less likelihood of developing contrast induced nephrotoxicity when iodixanol (Visipaque) is used rather than the low osmolar, nonionic contrast medium iohexol."

    Nephrotoxic Effects in High Risk Patients Undergoing Angiography
    Aspelin R et al.
    N Engl J Med 2003;348:491-499
  • "When protocols involving multiple scans are designed, an effort should be made to obtain as much diagnostic information as necessary with a sufficient but not unnecessary amount of radiation whenever possible."

    Patient Radiation Dose at CT Urography and Conventional Urography
    Nawfel RD et al.
    Radiology 2004; 232:126-132
  • "Measurements made from curved planar images are typically inaccurate because of the geometric distortion that occurs at increasing distances from the centerline."

    Value of Curved Planar Reformations in MDCT of Abdominal Pathology
    Desser TS et al.
    AJR 2004;182:1477-1484
  • "Bladder cancer tends to show peak enhancement with the 60-second scanning delay. Multidetector row helical CT is useful in the detection and staging of bladder cancer."

    Bladder Cancer: Analysis of Multidetector Row Helical CT Enhancement Pattern and Accuracy in Tumor Detection and Perivesical Staging
    Kim et al.
    Radiology 2004; 231:725-731
  • "Sensitivity and specificity in the diagnosis of perivesical invasion were 89% and 95% respectively, in 67 patients and increased to 92% and 98% respectively, in 44 patients with a time interval of 7 or more days between TURP and CT."

    Bladder Cancer: Analysis of Multidetector Row Helical CT Enhancement Pattern and Accuracy in Tumor Detection and Perivesical Staging
    Kim et al.
    Radiology 2004; 231:725-731
  • "The cancer detection rate and positive predictive value for cancer detection was 97% and 95% respectively, in 67 patients and increased to 100% and 100% in 44 patients with a time interval of 7 or more days between TURP and CT."

    Bladder Cancer: Analysis of Multidetector Row Helical CT Enhancement Pattern and Accuracy in Tumor Detection and Perivesical Staging
    Kim et al.
    Radiology 2004; 231:725-731
  • Bladder Cancer Enhancement

    Attenuation Value40 second scanning delay60 second scanning delay100 second scanning delay
    Mean plus standard deviation75 ± 14106 ± 1484 ± 14
    range55-10778-12955-119


    Radiology 2004; 231:725-731
  • "Multidetector row CT can help assess well the renal vasculature and the urinary tract of living renal donors."

    Living Donor Kidneys: Usefulness of Multi-Detector Row CT for Comprehensive Evaluation
    Kim JK et al.
    Radiology 2003; 229:869-876
  • "Detection rate of CT angiography was 98% for arteries and 98% for veins."

    Living Donor Kidneys: Usefulness of Multi-Detector Row CT (4 row) for Comprehensive Evaluation
    Kim JK et al.
    Radiology 2003; 229:869-876
  • "MDCT angiography is highly accurate for detecting vascular anomalies and providing anatomic information for laparoscopic living donor nephrectomy."

    Multidetector CT angiography for preoperative evaluation of living laparoscopic kidney donors.
    Kawamoto S, Montgomery RA, Lawler LP, Horton KM, Fishman EK AJR 2003 Jun;180(6):1633-8.
  • "Our study found a 9.9% prevalence of ovarian varices in the general population. Our findings suggest that half (57%)the patients with ovarian varices have pelvic congestion syndrome and that most (77%) of them benefit from ovarian vein embolization or ligation."

    Ovarian Varices in Healthy Female Kidney Donors: Incidence , Morbidity and Clinical Outcome
    Belenky A et al.
    AJR 2002; 179:625-627
  • Renal Cell Carcinoma: Facts

    - 85% of all renal cancers in adults
    - 30,000 new cases diagnosed in the US each year
    - M>F by 2-1
    - Peak incidence is age 50-70
    - Tumors are adenocarcinomas
  • Renal Cell Carcinoma: Risk Factors

    - Acquired cystic renal disease
    - Chronic renal failure
    - Von Hippel Lindau disease
    - Smoking
    - Hereditary renal cell carcinoma
  • "The prevalence of a hemodynamically significant stenosis isolated to an accessory renal artery was 1.5% in our study. Thus, failure to detect accessory renal arteries should not unduly affect the utility of a non-invasive test for detecting renovascular hypertension."

    Is It Necessary to Study Accessory Arteries When Screening the Renal Arteries for Renovascular Hypertension
    Bude RO et al.
    Radiology 2003;226:411-416
  • "There is no statistically significant difference between 3D MR angiography and multidetector row CT angiography in the detection of hemodynamically significant arerial stenosis of the aortoiliac and renal arteries."

    Aortoiliac and Renal Arteries: Prospective
    Intraindividual Comparison of Contrast Enhanced three Dimensional MR Angiography and Multidetector Row CT Angiography
    Willmann JK et al.
    Radiology 2003;226:798-811
  • "Patient acceptance was best for CT angiography."

    Aortoiliac and Renal Arteries: Prospective
    Intraindividual Comparison of Contrast Enhanced three Dimensional MR Angiography and Multidetector Row CT Angiography
    Willmann JK et al.
    Radiology 2003;226:798-811
  • CT Urography: Protocol

    - Unenhanced CT from kidneys to bladder
    - Nephrographic phase from diaphragm to iliac crests with 110 sec delay
    - Excretory phase at 8 minutes from kidneys thru bladder
    - Multidetector Row CT Urography in the Evaluation of Hematuria
    Joffe SA et al
    RadioGraphics 2003;23:1441-1456
  • Papillary Necrosis: Etiologies

    - Diabetes
    - Analgesic abuse
    - Sickle cell disease
    - Renal vein thrombosis
    - Obstructive uropathy
  • "Multidetector row CT can help assess well the renal vasculature and the urinary tract of living renal donors."

    Living Donor Kidneys: Usefulness of Multi-Detector Row CT for Comprehensive Evaluation
    Kim JK et al.
    Radiology 2003; 229:869-876
  • "Detection rate of CT angiography was 98% for arteries and 98% for veins."

    Living Donor Kidneys: Usefulness of Multi-Detector Row CT (4 row) for Comprehensive Evaluation
    Kim JK et al.
    Radiology 2003; 229:869-876
  • "At our institution, CT urography virtually replaced conventional urography in the evaluation of patients with hematuria and has proven successful in depicting a wide range of diseases affecting the urinary tract."

    Multidetector CT Urography with Abdominal Compression and Three Dimensional Reconstruction
    Chow LC et al.
    AJR 2001;177:849-855
  • "CT Angiography produced interpretable multiplanar images of the renal artery, even with a a metallic stent in place, and was adequate for determining stent patency. Compared with catheter angiography, the intrastent luminal diameter was underestimated in most patients who underwent CT Angiography."

    Thin-Section Multidetector CT Angiography of Renal Artery Stents
    Behar JV et al.
    AJR 2002;178:1155-1159
  • "The diameter of the renal artery stent lumen measured on catheter angiography (mean, 5.9 +/- 1.3 mm) was greater than that on CT angiography (mean stent lumen diameter for direct axial plane was 4.6 +/- 1.0 mm)."

    Thin-Section Multidetector CT Angiography of Renal Artery Stents
    Behar JV et al.
    AJR 2002;178:1155-1159
  • von Hippel-Lindau Disease: Facts

    - Autosomal dominant familial tumor syndrome
    - High penetrance with variable expression
    - Prevalence of one in 50,000
    - Defect in short arm of chromosome 3
  • von Hippel-Lindau Disease: organ involvement

    - Kidney
    - Adrenal
    - Pancreas
    - Brain
    - Spinal cord
    - Retina
  • von Hippel-Lindau Disease: Renal Pathology

    - Renal cysts- occur in 50-75% of patients and are usually multiple and bilateral
    - Renal cell carcinoma-occur in 28-45% of patients and occur at a younger age (30-36 yrs). The lesions are often multiple and bilateral and may be hypovascular or cystic lesions with mural nodules
  • von Hippel-Lindau Disease: Adrenal Pathology

    - Pheochromocytoma
    - Occur in up to 30% of families with VHL
    - They are bilateral in up to 50% of patients with a malignancy rate of around 10%
    - Up to 18% are extraadrenal in location
  • von Hippel-Lindau Disease: Pancreatic Pathology

    - Occur in up to 77% of patients
    - Lesions include
    - Simple pancreatic cysts
    - Serous cystadenomas
    - Neuroendocrine tumors
    - Pancreatic carcinoma
  • von Hippel-Lindau Disease: Uncommon Pathology

    - Liver cysts
    - Cystadenomas of the epididymis and broad ligament
  • "In evaluating Robson stage I of renal cell carcinoma, we were able to diagnose fat infiltration on 1-mm scans with 96% sensitivity, 93% specificity, and 95% accuracy; the positive and negative predictive values were, respectively, 100% and 93%."

    High-Resolution Multidetector CT in the Preoperative Evaluation of Patients with Renal Cell Carcinoma
    Catalano C et al.
    AJR 2003; 180:1271-1277
  • "On portal venous phase contrast enhanced CT scans, attenuation greater than 70HU or moderate or marked internal heterogeneity favor a diagnosis of renal cell carcinoma oer a diagnosis of high attenuation renal cyst."

    Distinction of Renal Cell carcinomas from High Attenuation Renal Cysts at Portal Venous Phase Contrast Enhanced CT
    Suh M et al
    Radiology 2003; 228:330-334
  • Sickle Cell Disease:Organ Involement

    - Bone
    - Brain
    - Lungs
    - Liver
    - Spleen
    - Kidney
  • Sickle Cell Disease: Subgroups

    - SS disease (homozygous Hb SS)
    - SC disease
    - S-thal
  • Sickle Cell trait is associated with a rare renal tumor- medullary carcinoma.
  • Sickle Cell Disease: Renal Involvement

    - Glomerulosclerosis leading to
    - Proteinuria
    - Nephrotic syndrome
    - Renal failure
  • "The attenuation coefficient of a cystic renal lesion increased by no more than 10H among the unenhanced, corticomedullary, and parenchymal phase scans."

    Analysis of Changes in Attenuation of Proven Renal Cysts on Different Scanning Phases of Triphasic MDCT
    Chung EP et al.
    AJR 2004; 182:405-410
  • "This study shows that cystic lesions typically reveal a change in attenuation of less than 10HU between the scanning phases of a triphasic MDCT, affirming Bosniaks initial assertion that 10HU is a reasonable cutoff for determining enhancement in renal lesions."
  • "This study shows that cystic lesions typically reveal a change in attenuation of less than 10HU between the scanning phases of a triphasic MDCT, affirming Bosniaks initial assertion that 10HU is a reasonable cutoff for determining enhancement in renal lesions."

    Analysis of Changes in Attenuation of Proven Renal Cysts on Different Scanning Phases of Triphasic MDCT
    Chung EP et al.
    AJR 2004; 182:405-410
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