SMA Syndrome

Reformat in sagittal plane to see aorta and SMA

• Antiperistaltic flow of barium proximal to obstruction

• Relief of obstruction in prone, knee-chest, or left lateral decubitus positions

TOP DIFFERENTIAL DIAGNOSES

• Duodenal obstruction (other causes)

• Intestinal scleroderma

• Duodenal stricture

PATHOLOGY

• Predisposing conditions

Weight loss → depletion of retroperitoneal fat, leading to narrowed aorto-mesenteric angle

Anatomical and congenital anomalies

Postoperative states (e.g., scoliosis)

CLINICAL ISSUES

• Postprandial epigastric pain, nausea, vomiting

Pain relieved in prone, knee-chest, or left lateral decubitus position

• Surgery (bypassing duodenum) indicated when conservative therapy fails

DIAGNOSTIC CHECKLIST

• Can be mimicked by or made worse by other causes of duodenal dilation (e.g., scleroderma)

(Left) Supine film from an upper GI series in a woman with recent weight loss and early satiety shows an abrupt, straight-line cut-off of the 3rd portion of duodenum as it crosses over the midline, with dilation and slow emptying of the proximal duodenum. There is also a duodenal diverticulum .

(Left) Supine film from an upper GI series in a woman with recent weight loss and early satiety shows an abrupt, straight-line cut-off of the 3rd portion of duodenum as it crosses over the midline, with dilation and slow emptying of the proximal duodenum. There is also a duodenal diverticulum .

(Right) Axial CECT shows marked distention of the 2nd portion of the duodenum and stomach. The 3rd portion of the duodenum is compressed as it passes between the aorta and the superior mesenteric artery (SMA).

(Right) Axial CECT shows marked distention of the 2nd portion of the duodenum and stomach. The 3rd portion of the duodenum is compressed as it passes between the aorta and the superior mesenteric artery (SMA).

(Left) Coronal reformatted CT in the same case shows dilation of the second portion of duodenum , while the remaining bowel is collapsed. Note this patient’s thin body habitus.

(Left) Coronal reformatted CT in the same case shows dilation of the second portion of duodenum , while the remaining bowel is collapsed. Note this patient’s thin body habitus.

(Right) Sagittal-reformatted CT in the same case shows a very narrow angle between the superior mesenteric artery and the aorta, with compression of the 3rd portion of duodenum as it passes between these vessels.

(Right) Sagittal-reformatted CT in the same case shows a very narrow angle between the superior mesenteric artery and the aorta, with compression of the 3rd portion of duodenum as it passes between these vessels.

TERMINOLOGY

Definitions

• Vascular compression of 3rd portion of duodenum between aorta and superior mesenteric artery (SMA)

IMAGING

General Features

• Best diagnostic clue

Dilated 1st and 2nd portions of duodenum with abrupt, straight-line transition to collapsed duodenum as it crosses spine

Only gold members can continue reading. Log In or Register to continue

Stay updated, free articles. Join our Telegram channel

Tags: Diagnostic Imaging Gastrointestinal

Nov 16, 2016 | Posted by admin in GASTROINTESTINAL IMAGING | Comments Off

Full access? Get Clinical Tree

Get Clinical Tree app for offline access

Get Clinical Tree app for offline access