Imaging Approach to the Small Intestine

Published on 18/07/2015 by admin

Filed under Radiology

Last modified 22/04/2025

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Serosa
Longitudinal muscle
Circular muscle
Submucosa
Mucosa
(Top) There are 5 layers of the bowel wall. The innermost is the mucosa, the absorptive surface of the gut. The other layers are the submucosa, circular muscle, longitudinal muscle, and serosa.

Lymphoid nodule
Muscularis mucosa
Circular fold & lamina propria
Villi
Submucosa
Circular muscle
Longitudinal muscle
(Bottom) The mucosal surface of the jejunum is increased by prominent villi, which are finger-like projections of mucosa. The submucosa has a network of capillaries, lymphatics, and a nerve plexus. The jejunum has few small, discrete lymphoid nodules. Although there is no sharp point of transition between the jejunum and ileum, the wall of the ileum becomes thinner and less vascular, with shorter and more widely spaced transverse folds, and more prominent lymphoid follicles.

(Left) CT of a man with abdominal distention months after stem cell transplantation shows extensive pneumatosis , but no ascites or ileus. These findings, along with no clinical evidence for bowel ischemia, correctly suggested benign, medication-induced pneumatosis.

(Left) CT of a man with abdominal distention months after stem cell transplantation shows extensive pneumatosis , but no ascites or ileus. These findings, along with no clinical evidence for bowel ischemia, correctly suggested benign, medication-induced pneumatosis.

(Right) Axial CECT shows diffuse SB wall thickening, with near water density submucosal edema, and intense mucosal enhancement in a patient with “shock bowel” following abdominal trauma. This is a form of reversible bowel ischemia.

(Left) CT of a young woman with acute onset of abdominal pain shows wedge-shaped and striated zones of decreased attenuation within the kidneys.

(Left) CT of a young woman with acute onset of abdominal pain shows wedge-shaped and striated zones of decreased attenuation within the kidneys.

(Right) CT in the same case shows long segmental SB wall thickening with submucosal edema . This, along with the renal inflammatory or ischemic changes in a young patient, suggested the diagnosis of vasculitis as the underlying disease process, subsequently confirmed by renal biopsy.

(Right) CT in the same case shows long segmental SB wall thickening with submucosal edema . This, along with the renal inflammatory or ischemic changes in a young patient, suggested the diagnosis of vasculitis as the underlying disease process, subsequently confirmed by renal biopsy.

(Left) CT in a 58-year-old man with malignant melanoma and presenting with acute abdominal pain shows a classic SB intussusception with the intussusceptum and its mesenteric fat and vessels inside the intussuscipiens.

(Left) CT in a 58-year-old man with malignant melanoma and presenting with acute abdominal pain shows a classic SB intussusception with the intussusceptum and its mesenteric fat and vessels inside the intussuscipiens.

(Right) CT in the same case shows the lead point of the intussusception , a metastasis in the wall of the intussusceptum.

(Right) CT in the same case shows the lead point of the intussusception , a metastasis in the wall of the intussusceptum.

(Left) NECT in an elderly woman with abdominal pain and vomiting shows a cluster of dilated, fluid-distended SB segments with twisting and distortion of the mesenteric vessels .

(Left) NECT in an elderly woman with abdominal pain and vomiting shows a cluster of dilated, fluid-distended SB segments with twisting and distortion of the mesenteric vessels .

(Right) CT reconstruction shows the dilated SB , arrayed as “balloons on strings” representing the engorged mesenteric vessels , classic findings of a closed-loop SBO. Interloop ascites , mesenteric edema and poor definition of the SB walls suggest ischemia. Closed-loop SBO with infarcted bowel was confirmed at surgery.

(Right) CT reconstruction shows the dilated SB , arrayed as “balloons on strings” representing the engorged mesenteric vessels , classic findings of a closed-loop SBO. Interloop ascites , mesenteric edema and poor definition of the SB walls suggest ischemia. Closed-loop SBO with infarcted bowel was confirmed at surgery.

(Left) CT enterography in a young man with abdominal pain and diarrhea shows good distention of the SB and colon with water density contrast medium. The SB is normal except for the terminal ileum which shows luminal narrowing, wall thickening, and mucosal hyperenhancement. Mesenteric vascular engorgement is present .

(Left) CT enterography in a young man with abdominal pain and diarrhea shows good distention of the SB and colon with water density contrast medium. The SB is normal except for the terminal ileum which shows luminal narrowing, wall thickening, and mucosal hyperenhancement. Mesenteric vascular engorgement is present .

(Right) Coronal CT in the same case shows the active inflammation of the terminal ileum and local fibrofatty proliferation , typical features of Crohn disease.

(Right) Coronal CT in the same case shows the active inflammation of the terminal ileum and local fibrofatty proliferation , typical features of Crohn disease.

(Left) CECT enterography in an elderly woman with acute GI bleeding shows a brightly enhancing mass arising from the ileum. Within the affected segment of bowel, there are high density foci of extravasated contrast material indicating active bleeding from the mass.

(Left) CECT enterography in an elderly woman with acute GI bleeding shows a brightly enhancing mass arising from the ileum. Within the affected segment of bowel, there are high density foci of extravasated contrast material indicating active bleeding from the mass.

(Right) Coronal CT in the same case shows the hypervascular mass having an endoluminal and exophytic component, typical of a GI stromal tumor, confirmed at surgery.

(Right) Coronal CT in the same case shows the hypervascular mass having an endoluminal and exophytic component, typical of a GI stromal tumor, confirmed at surgery.

Diagnostic Imaging_ Gastrointes - Michael P Federle