Answer
Most bowel pathologies cause thickening of the bowel wall. On bowel examination, a target sign is usually seen. With this sign, a hypoechoic wall surrounds the echogenic mucosa, intraluminal mucous, air, and other bowel contents. This target may be round or oval (pseudo-kidney sign).
Under normal physiologic conditions, the hypoechoic bowel wall measures less than 4 mm. With few exceptions, this 4-mm rule may be applied to the whole of the bowel. Under pathologic conditions, the bowel wall thickens symmetrically in target fashion. It may be thickened asymmetrically when the echogenic lumen is displaced to one side on a true cross-section; this is the atypical target sign.
Most bowel pathology, whether inflammatory or neoplastic, may be inferred from the aforementioned signs. As with most imaging findings, these signs are nonspecific and suggest only a differential diagnosis. US findings of mural thickening of the bowel with a paucity of luminal content may be helpful in the detection of IBDs. However, the findings are nonspecific, and the differential diagnosis must be related to the specific segment of the bowel involved.
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Double-contrast barium enema study shows changes of early disease. Note the granular mucosa.
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Double-contrast barium enema studies show changes of early disease. Note the granular mucosa.
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Double-contrast barium enema studies in a 44-year-old man known to have a long history of ulcerative colitis. Images show total colitis and extensive pseudopolyposis.
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Plain abdominal radiograph in a patient (same as in the previous image) who presented with an acute exacerbation of his symptoms. Image shows thumbprinting in the region of the splenic flexure of the colon.
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Plain abdominal radiograph obtained 2 days later in the same patient as in the previous image shows distention of the transverse colon associated with mucosal edema. The maximum transverse diameter of the transverse colon is 7.5 cm. The patient was treated for toxic megacolon.
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A 22-year-old man presented with abdominal pain, passage of blood and mucus per rectum, abdominal distention, fever, and disorientation. Findings from sigmoidoscopy confirmed ulcerative colitis. Abdominal radiographs obtained 2 days apart show mucosal edema and worsening of the distention in the transverse colon. The patient's clinical condition deteriorated over the next 36 hours despite steroid and antibiotic therapy, and the patient had to undergo total colectomy and ileostomy.
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Plain abdominal radiograph in a patient with known ulcerative colitis who presented with abdominal pain, peritonism, and leukocytosis. At surgery, a perforated toxic megacolon superimposed on ulcerative colitis was confirmed.
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Increased postrectal space is a known feature of ulcerative colitis.
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Plain abdominal radiograph on a patient with known ulcerative colitis who presented with an acute exacerbation of his symptoms. Image shows thumbprinting in the region of the splenic flexure of the colon.
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Double-contrast barium enema study shows pseudopolyposis of the descending colon.
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Single-contrast enema study in a patient (same patient as in the previous image) with known ulcerative colitis in remission shows a benign stricture of the sigmoid colon.
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Plain abdominal radiograph in a 26-year-old with a 10-year history of ulcerative colitis shows a long stricture/spasm of the ascending colon/cecum. Note the pseudopolyposis in the descending colon.
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Single-contrast enema study in a patient with total colitis shows mucosal ulcers with a variety of shapes, including collar-button ulcers, in which undermining of the ulcers occurs, and double-tracking ulcers, in which the ulcers are longitudinally orientated.
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Double-contrast barium enema study shows total colitis. Note the granular mucosa in the cecum/ascending colon and multiple strictures in the transverse and descending colon in a patient with a more than a 20-year history of ulcerative colitis.
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Single-contrast barium enema study shows burnt-out ulcerative colitis.
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Scan obtained with technetium-99m hexamethylpropylamine oxime (HMPAO)–labeled WBCs in a patient with active colitis involving the transverse and descending colon.
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Intravenous urogram shows features of ankylosing spondylitis.
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Lateral radiograph of the lumbar spine shows a bamboo spine.
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Single-contrast barium enema study in a patient with Shigella colitis.
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Postevacuation image obtained after a single-contrast barium enema study shows extensive mucosal ulceration resulting from Shigella colitis.
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Double-contrast barium enema studies show granular mucosa associated with Campylobacter colitis.
