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- “The duodenum, a C-shaped structure measuring approximately 25–30 cm in length, spans from the gastric pylorus to the ligament of Treitz. The first segment of the duodenum, the duodenal bulb, measures approximately 5 cm and is mobile whereas the rest of the duodenum is fixed to the retroperitoneum. The second segment approximates 7.5 cm in length and proceeds from the superior duodenal flexure to the inferior flexure. The third segment crosses horizontally from right to left for 12–13 cm. The fourth ascending segment runs 2.5 cm to the duodenojejunal angle and creates the duodenojejunal flexure that connects to the jejunum. The superior pancreaticoduodenal artery supplies the proximal section of the duodenum, and the inferior pancreaticoduodenal and superior mesenteric arteries supply the duodenum more distally.”
Imaging spectrum of non‑neoplastic and neoplastic conditions of the duodenum: a pictorial review
Cinthia Del Toro et al.
Abdominal Radiology (2023) 48:2237–2257 - “Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor of the gastrointestinal tract. Tumors less than 2 cm are generally asymptomatic and benign and are discovered incidentally. On CT, these tumors present with variable density, showing patchy enhancement, necrosis, and ulcerations when greater than 5 cm. MR images show low intensity on T1-weighted MRI, and intermediate to high intensity with T2-weighted MRI, with associated diffusion restrictionT2 hyperintense areas of necrosis and T1 hyperintense areas of internal hemorrhage can be observed. Duodenal GISTs are found primarily in the 2nd portion, and additional findings are central umbilication or ulceration of the mucosa. When metastases are present, they usually involve the liver and the peritoneum.”
Imaging spectrum of non‑neoplastic and neoplastic conditions of the duodenum: a pictorial review
Cinthia Del Toro et al.
Abdominal Radiology (2023) 48:2237–2257 - “Duodenal adenocarcinomas are extremely rare, accounting for less than 0.5% of all gastrointestinal tract malignancies. The genetic predisposition of adenocarcinomas is related to familial adenomatous polyposis, Lynch syndrome, Peutz–Jeghers syndrome, Crohn’s disease, and Celiac disease. Duodenal adenocarcinomas typically present in the 7th decade of life. The most common clinical presentation is gastrointestinal tract obstruction, bleeding, and jaundice. The CT and MRI features of duodenal adenocarcinomas include a polypoid mass, a concentric or asymmetric wall thickening, and an ulcerated mass with irregular borders. Adenocarcinomas present with thickening of the small bowel wall, luminal stenosis and may also produce partial or complete intestinal obstruction. Adjacent lymphadenopathy can also be present.”
Imaging spectrum of non‑neoplastic and neoplastic conditions of the duodenum: a pictorial review
Cinthia Del Toro et al.
Abdominal Radiology (2023) 48:2237–2257
- 58 adult patients with GI bleeding were studied
- 16 of 58 has a bleeding site identified (28%)
- CT enterography found 14 of 16 sites of bleeding
- Capsule endoscopy found 6 of 16 sites of blleding
- Main difference was in detecting small bowel tumors where CT was 9/9 and capsule
enddoscopy 3/9 - “ The sensitivity of multiphase CT enterography in the detection of small bowel lesions causing
obscure gastrointestinal bleeding (OGIB) was significantly greater than that of capsule
endoscopy (88% vs 38% respectively) largely because CT enterography depicted more small
bowel masses (nine of nine (100%)) vs three of nine patients(33%)) respectively.”
Prospective Blinded Comparison of Wireless Capsule Endoscopy and Multiphase CT
Enterography in Obscure Gastrointestinal Bleeding
Huprich JE et al.
Radiology 2011; 260:744-751 - “ On the basis of these findings, the addition of multiphase CT enterography to the routine
diagnostic workup of patients with OGIB should be considered, particularly in patients with
negative findings at capsule endoscopy.”
Prospective Blinded Comparison of Wireless Capsule Endoscopy and Multiphase CT
Enterography in Obscure Gastrointestinal Bleeding
Huprich JE et al.
Radiology 2011; 260:744-751 - “In this referral population, the sensitivity of CT enterography for detecting small bowel bleeding
sources and small bowel masses was significantly greater than that of capsule endoscopy. On the
basis of these findings, the addition of multiphase CT enterography to the routine diagnostic
workup of patients with OGIB should be considered, particularly in patients with negative
findings at capsule endoscopy.”
Prospective Blinded Comparison of Wireless Capsule Endoscopy and Multiphase CT
Enterography in Obscure Gastrointestinal Bleeding
Huprich JE et al.
Radiology 2011; 260:744-751 - “ Low-dose CT Enterography using 50% reduced dose performed similarly to standard-dose
CTE in identifying findings of enteric inflammation of Crohn disease.”
A Prospective Comparison of Standard-Dose CT Enterography and 50% Reduced-Dose CT
Enterography With and Without Noise Reduction for Evaluating Crohn Disease
Lee SJ et al.
AJR 2011; 197:50-57 - “ Low-dose CT Enterography using 50% reduced dose performed similarly to standard-dose
CTE in identifying findings of enteric inflammation of Crohn disease. Although a noise
reduction method markedly reduced image noise in half-dose examinations, its effect on image
quality was not as great and was reader dependent.”
A Prospective Comparison of Standard-Dose CT Enterography and 50% Reduced-Dose CT
Enterography With and Without Noise Reduction for Evaluating Crohn Disease
Lee SJ et al.
AJR 2011; 197:50-57 - “ Small intestinal MDCT-VE technique has high diagnostic accuracy for the detection of intestinal tumors. Contrast enhancement and adequate intestinal tract gas-filling can improve the detection rate for small intestinal tumors.”
Small intestinal tumors: diagnostic accuracy of enhanced multi-detector CT virtual endoscopy
Su X et al.
Abdom Imaging (2011) DOI: 10.2007/soo261-011-9776-z - “ MDCT-VE correctly identified 30/33 cases with one false positive diagnosis: sensitivity 90.9%, specificity 98.9% and accuracy 96.8%.”
Small intestinal tumors: diagnostic accuracy of enhanced multi-detector CT virtual endoscopy
Su X et al.
Abdom Imaging (2011) DOI: 10.2007/soo261-011-9776-z - MDCT-VE Study Protocol
Prep patient with castor oil and magnesium sulfate solution
6 g aerogenesis agent
Air introduced via pump into rectum and into ileum
Study was performed on a 4 slice system
4 scans were obtained;
- Unenhanced scan
- 30 and 80 second delay in supine position (injection of 3.5 -5 ml/sec at 100 ml of Visipaque
- 180 second delay in the prone position - MDCT-VE Study Anaysis
- Axial images
- Coronal,sagittal, oblique
- Virtual endoscopy
- Vascular mapping across all aspects in design - CT Enterography Protocol:
- Some sites use 1350 ml given over 40 or 60 minutes
- The more VoLumen the higher the chance of adverse reaction related to the sorbitol in the contrast - CT Enterography:
- Protocol 450 ml pre-mixed bottles
- Protocols involve the patient drinking either 900 ml or 1350 ml
- Sequence is450 ml VoLumen
0-10 minutes
450 ml VoLumen
10-20 minutes
450 ml water
20-30 minutes
"When an abnormal small bowel loop is recognized, a pattern approach as discussed herein can be used to narrow the differential diagnosis."
A Pattern Approach to the Abnormal Small Bowel: Observations at MDCT and CT Enterography
Macari M, Megibow AJ, Balthazar EJ
AJR 2007;188:1344-1355- Location of wall involvement
Mucosa
- Neoplasms
- Crohn's disease
- Infectious processes
- Intestinal ischemia
Submucosa (edema or blood cause a target sign)- Intramural hemorrhage
- Vasculitis
- Ischemia
- Angioedema
- Hypoalbuminemia
Serosal surface- Metastases
- Carcinoid tumors
- Endometriosis
- Inflammatory diseases
- Symmetric versus Asymmetric Wall Thickening
- Most causes of symmetric wall thickening are benign like crohn’s disease
- Most causes of asymmetric wall thickening are malignancies but crohn’s disease and TB can also be asymmetric thickening - Degree of Thickening
- Normal bowel wall thickness 2 mm or less
- Mild thickening 3-4 mm- Hypoalbuminemia
- Infectious enteritis
- Mild crohns's disease
- Ischemia due to lack of arterial inflow
- Diminished Enhancement
- Typical finding in small bowel ischemia
- Can be due to causes ranging from volvulus to SMA or SMV thrombosis to sepsis or shock - Heterogeneous Enhancement
- This is a typical appearance for small bowel tumors especially adenocarcinoma
- Lymphoma and metastases may also have this appearance - Double halo or target appearance
- Benign process with enhancement of mucosa and serosa but not submucosa
- Originally "classic" for crohns but can be seen with crohn's disease, infection, ischemia, radiation enteritis, angioedema and hemorrhage - Mural enhancement pattern
Four types
- Double halo or target appearance- Homogeneous or hyperenhancement pattern- Heterogenous enhancement
- Decreased or absent enhancement - Evaluation of Small Bowel Pathology: Criteria
- Pattern of enhancement
- Length of involvement
- Degree of thickening
- Whether thickening is symmetrical or asymetrical
- Location of lesion (proximal or distal)
- Location of lesion in bowel wall (mucosal,submucosal or serosal)
- Associated abnormalities in mesentery and vessels - CT Enterography: Indications
- Obscure GI bleeding
- The presence and activity of Crohn's disease
- Suspected small bowel neoplasia - Celiac Disease: CT Findings
- Small bowel dilatation
- Small bowel intussusception
- Villous atrophy
- Jejunization of the ileum (decrease in jejunal folds and increase in ileal folds)
- Mesenteric adenopathy
- Increased incidence of lymphoma - CT Enterography: GI Bleed
- Angiodysplasia (number one cause)
- Vascular dysplasias
- Small bowel neoplasms (benign and malignant)
- Meckel diverticulum "CT enterography also has been shown to be more cost effective in the long term assessment and follow-up of patients, especially those with established Crohn disease. MR enterography is being used more frequently because of the advantage of lack of radiation. However, the superior spatial resolution of CT enterography still makes it the initial imaging modality of choice in many adult patients"
CT Enterography: Principles, Trends, and Interpretation of Findings
Elsayes KM et al.
RadioGraphics 2010; 30:1955-1974"CT enterography also has been shown to be more cost effective in the long term assessment and follow-up of patients, especially those with established Crohn disease."
CT Enterography: Principles, Trends, and Interpretation of Findings
Elsayes KM et al.
RadioGraphics 2010; 30:1955-1974- CT Enterography: Crohn Disease
Inactive crohn disease findings include
- Submucosal fat deposition
- Pseudosacculation
- Fibrofatty proliferation
- Fibrotic strictures
- “skip lesions” common (as opposed to Ulcerative colitis with backwash ileitis” - CT Enterography: Crohn Disease
Active crohn disease findings include
- Mucosal hyperenhancement
- Wall thickening
- Mural stratification (seeing bowel layers) with prominent vasa recta (comb sign)
- Mesenteric fat stranding - CT Enterography: Applications
- Crohn disease (define activity or detect strictures)
- Suspected GI bleed
- Suspected tumors
- Suspected mesenteric ischemia - CT Enterography: Technique
1350 ml of VoLumen given at a sequence of;
- 450 ml at 60 minutes
- 450 ml at 40 minutes
- 225 ml at 20 minutes
- 225 ml at 10 minutes prior to scanning125 ml of Isovue-370 injected at 4 cc/sec
CT Enterography: Principles, Trends, and Interpretation of Findings
Elsayes KM et al.
RadioGraphics 2010; 30:1955-1974 "CT enterography allows excellent visualization of the entire thickness of the bowel wall and depicts extraenteric involvement as well, providing more detailed and comprehensive information about the extent and severity of the disease process."
CT Enterography: Principles, Trends, and Interpretation of Findings
Elsayes KM et al.
RadioGraphics 2010; 30:1955-1974"The overall sensitivity and specificity of CT enteroclysis in identifying patients with small bowel carcinoid tumors were 100% and 96.2%, respectively. The negative predictive value of CT enteroclysis was 100% and the positive predictive value,94.7%."
Value of CT Enteroclysis in Suspected Small Bowel Carcinoid Tumors
Kamaoui I et al.
AJR 2010; 194:629-633"CT enteroclysis should be considered an excellent tool for the diagnosis of the carcinoid tumor before any surgical procedure."
Value of CT Enteroclysis in Suspected Small Bowel Carcinoid Tumors
Kamaoui I et al.
AJR 2010; 194:629-633"In the diagnosis of anastomotic recurrence, severe anastomotic stenosis was 95% sensitive, both comb sign and stratification were 95% specific, and stratification was 92% accurate."
Suspected Anastomotic Recurrence of Crohn Disease after Ileocolic Resection: Evaluation with CT Enteroclysis
Soyer P et al.
Radiology 2010; 254:755-764" CT enteroclysis yields objective and relatively specific morphologic criteria that help differentiate between recurrent disease and fibrostenosis at the anastomotic site after ileocolic resection for Crohn disease."
Suspected Anastomotic Recurrence of Crohn Disease after Ileocolic Resection: Evaluation with CT Enteroclysis
Soyer P et al.
Radiology 2010; 254:755-764- CT Enterography: Protocol
- Some sites use 1350 ml given over 40 or 60 minutes
- The more VoLumen the higher the chance of adverse reaction related to the sorbitol in the contrast - CT Enterography: Protocol
- 450 ml pre-mixed bottles
- Protocols involve the patient drinking either 900 ml or 1350 ml
- Sequence is
450 ml VoLumen0-10 minutes450 ml VoLumen10-20 minutes450 ml water20-30 minutes - Triphasic CT Enterography
- 1350 ml of VoLumen drank over 45 minutes
- 150 ml of Omnipaque-350 injected at 4 cc/sec
- Arterial phase based on bolus trigger, and phases 20 and 90 seconds after this
- Axial and coronal images reviewed
- Glucagon (0.5 mg) used
- Hara A et al. AJR 2009; 193:1252-1260 "This study found that triphasic CT enterography has the potential to identify the source of gastrointestinal bleeding in up to half of the patients if reader errors are eliminated."
Preliminary Estimate of Triphasic CT Enterography Performance in Hemodynamically Stable Patients with Suspected Gastointestinal Bleeding
Hara A et al.
AJR 2009; 193:1252-1260"Because of the potential for perception errors, radiologists should familiarize themslves with the appearance of bleeding sources at CT enterography."
Preliminary Estimate of Triphasic CT Enterography Performance in Hemodynamically Stable Patients with Suspected Gastointestinal Bleeding
Hara A et al.
AJR 2009; 193:1252-1260"Triphasic CT enterography can be useful and complementary test in the evaluation of clinically stable patients with suspected gastrointestinal bleeding by identifying the bleeding source in one third to one half of patients."
Preliminary Estimate of Triphasic CT Enterography Performance in Hemodynamically Stable Patients with Suspected Gastointestinal Bleeding
Hara A et al.
AJR 2009; 193:1252-1260