Computed tomography and MRI may identify disease, localize and characterize the severity and extent of disease, indicate the presence of acute complications, assess the severity of inflammation, and monitor disease progression. When found in older children and adults, it should trigger a search for a lead point, such as an underlying neoplasm, inciting adhesion or foreign body. Contrast-enhanced CT of the abdomen and pelvis is currently the study of choice in patients with suspected acute diverticulitis, which manifests with pericolic inflammation, engorgement of the adjacent mesenteric vasculature, and focal colonic wall thickening with or without abscess formation ( Fig. The appearance of the bowel on CT varies widely depending on various factors such as the presence and configuration of the lead mass, presence of bowel dilatation and degree of obstruction, degree of bowel wall edema, and amount of invaginated mesenteric fat and blood vessels. As in all cases of IBD, CT (and increasingly MRI) is employed for determining disease activity. Differentiation will depend on the clinical history, distribution pattern, and often biopsy. Not uncommonly, UC is first diagnosed when patients present with these symptoms to the ED. Appendicitis on MRI is readily depicted on T2-weighted sequences acquired with and without fat suppression. When complicated by volvulus, CT shows a distended stomach and duodenum and an abrupt transition to decompressed bowel with a focal twist causing a “whirlpool” sign ( Fig. Other causes of large bowel obstruction include acute sigmoid diverticulitis and colonic volvulus. Earn up to 35 AMA PRA Category 1 Credits™and 25 SAM Credits. The sequelae of acute ischemic colitis include reversible ischemic colitis, chronic ulcerative ischemic colitis, ischemic colonic stricture, or colonic necrosis with perforation and sepsis. Sigmoid volvulus accounts for up to 75% of cases of volvulus of the bowel but accounts for less than 10% of all cases of intestinal obstruction in the United States. Treatment can either be conservative, including nasogastric decompression and nutritional supplementation, or surgical such as duodenojejunostomy. Some of the more commonly encountered causes of infectious colitis include Campylobacter jejuni , Yersinia enterocolitica , Salmonella typhi , and Clostridium difficile . Plain abdominal radiographs are commonly requested for acute medical emergencies on patients with non-specific abdominal symptoms and signs. The presence of an unusual quantity of colonic gas in this setting usually indicates nonobstructive ileus, partial SBO, or early complete SBO. Colonic intussusception refers to invagination or telescoping of a proximal loop of bowel (intussusceptum) into the lumen of an adjacent, distal segment of bowel (intussuscipiens). Diagnostic workup often starts with radiography, particularly if the ingested item is radiodense (e.g., metallic) or suspected to be lodged in the hypopharynx. 13-35 ). Colonoscopy with the retrieval of multiple biopsy specimens is the first-line study for diagnosing this disease. Viral causes are self-limited; however, fungal and parasitic organisms are typically treated with antifungal and antihelminthic drugs, respectively. Endoscopy and classic barium studies are critical in the initial diagnosis and staging of IBD in general because they are superior to cross-sectional imaging in the evaluation of the mucosa, particularly in early-stage disease. The first segment of the small intestine, the duodenum is typically 25 to 38 cm in length and extends from the gastric pylorus to the duodenojejunal flexure (ligament of Treitz). Marked wall thickening out of proportion to the degree of pericolic inflammation, obliteration of the expected mural enhancement pattern of the colon, the presence of mesenteric lymphadenopathy, and acute bowel obstruction are imaging findings that are suggestive of colonic carcinoma. A subset of patients with duodenal ulcers will have Zollinger-Ellison syndrome, typically caused by a gastrin-secreting tumor in the gastrinoma triangle, an anatomic space defined by the junctions of the cystic and common bile ducts, the neck and body of the pancreas, and the second and third portions of the duodenum. Complications of CD include abscesses, fistula formation, anal fissures, and colon cancer. Differentiating between mechanical obstruction and Ogilvie syndrome, also known as colonic pseudo-obstruction , has therapeutic implications and should be accomplished with barium enema. Unable to process the form. Focal, low-density lesions can be present in the spleen. In the majority of patients, CECT represents the first-line imaging modality of choice and is the most accurate imaging study with well-demonstrated sensitivity, specificity, and diagnostic accuracy exceeding 95% for the diagnosis of acute appendicitis. Other causes of cecal volvulus include cecal bascule with anterior folding of the cecum, postpartum ligamentous laxity, colonic distention, and chronic constipation. 13-8 ). Treatment options in cases of acute diverticulitis range from conservative management with antibiotics and bowel rest to emergent surgery in cases of complications. The diagnosis of cecal volvulus may be confirmed on contrast enema or CT. On contrast enema examination a beaklike tapering of the cecum is seen at the level of the volvulus, and contrast usually does not pass into the proximal colon or small bowel. Although in some cases a focal wall discontinuity or extraluminal gas may be found, many times a duodenal perforation may simply present with an intramural hematoma and/or adjacent fluid. 13-46 ). In addition, CT may show inflammation or fluid tracking along the connector tubing and/or port; when seen, this should prompt evaluation of the band as the site of erosion or infection ( Fig. English subtitles and a certificate are provided. It is characterized by stricture formation and obstruction. Because of high contrast, CT can better assess extent of fistulas in penetrating disease, mesenteric vascularity, and lymphadenopathy. A line drawn from the incisura to the greater curvature of the stomach represents the transition zone from body-type to antral-type mucosa, which is a frequent site for gastric ulcers. Inflammation of the stomach is most commonly diffuse, but it can also be focal process. On CT a target or double-halo appearance due to mural stratification is commonly identified. Despite overall low diagnostic accuracy and specificity, the kidney, ureter, and bladder (KUB) radiographic examination is still sometimes used as an initial imaging examination in patients with abdominal symptoms. Careful and systematic travel through the bowel loops in multiple planes is the key to success. The ileum has an abundance of lymphoid follicles, which are nearly absent in the jejunum. Treatment in patients with toxic megacolon may include operative intervention with colectomy and treatment of associated complications. 13-31 ). On imaging this appears as narrowing of the affected segment with associated soft tissue thickening, most often the pylorus. The presence of fibrofatty proliferation along the mesenteric border of the affected bowel is considered pathognomonic of this disease. Patients who have undergone organ transplantation also have an increased risk for developing bezoars, which is hypothesized to be secondary to decreased gastric motility, either due to vagus nerve injury or a side effect of cyclosporine. Adhesions are typically not seen, and the diagnosis is one of exclusion. Acute radiation enteritis occurs within the first few days or weeks after exposure. Dr Jeremy Jones (@dr_jbj) is a consultant pediatric radiologist at the Royal Hospital for Sick Children in Edinburgh, UK, and an honorary senior clinical lecturer at the University of Edinburgh. However, this imaging finding is nonspecific and may be seen in patients with CD, pseudomembranous colitis, ischemic and radiation enterocolitis, infectious colitis, and bowel edema. It can be secondary to intraperitoneal seeding, hematogenous spread, or direct extension from an adjacent visceral malignancy. The diverticulum can be associated with mural thickening and hyperenhancement, with focal calcifications at the base (enteroliths), and adjacent mesenteric fat stranding and fluid collections. Updated 27 July 2020 with 4 new videos and 50 review questions. With the use of MRI, the need for CT in cases of suspected acute appendicitis may be markedly decreased or eliminated altogether. Special Section on ER Abdominal Imaging. Although no underlying mechanical obstruction exists, Ogilvie syndrome is a significant cause of morbidity and death with possible progression to bowel ischemia and perforation. The small bowel mucosa is primarily affected, resulting in progressive villus inflammation and destruction, with resulting induction of crypt hyperplasia. The role of CT and MRI in CD has expanded with recent advances in technology allowing for rapid acquisition of high-resolution images of the bowel. The organism tends to inhabit the duodenum and jejunum. A false diagnosis of colonic obstruction, particularly in patients with obstructive symptoms, may lead to inappropriate surgical exploration. 13-18 ). Magnetic resonance enterography can play an important role in the follow-up of patients with established IBD, or it can be used to exclude IBD in a young patient who presents with symptoms suggesting the disease. The epithelium regenerates between acute inflammatory attacks, resulting in the formation of pseudopolyps, usually seen in long-standing disease. Gastric volvulus requires at least 180 degrees of rotation and gastric outlet obstruction. Perirectal abscess and fistulization are inflammatory conditions of the rectum and anus that can cause severe perirectal pain and sinus discharge, often sending patients to seek emergency medical attention. Patients with sigmoid volvulus are at increased risk for developing bowel ischemia by two mechanisms: arterial occlusion from mesenteric arterial torsion and mural ischemia due to increased wall tension of distended bowel. It affects multiple organs and has been called pseudo-Whipple disease because of clinical, histologic, and radiologic similarities. There is no exact point of transition between the jejunum and ileum, but differences in their usual location, caliber, fold pattern, and degree of vascularity allow distinction between the two. Clinically patients may present with normal serum amylase and lipase levels. 13-53 ). Pseudopolyps, which are nodular masses of inflamed mucosa, may be seen projecting into the lumen of affected colon. Herpes esophagitis typically presents with multiple small ulcers represented by pooled barium. Abdominal Emergency Radiology Course - Online. Ulcerative colitis typically affects patients between 15 and 25 years of age with women slightly more frequently affected than men. This course teaches key concepts in the interpretation of abdominal imaging (see course topics) and is ideal for health professionals involved in the imaging and management of emergency abdominal conditions. The presence of free air is indicative of bowel perforation. Small bowel obstruction can occur during the acute phase of CD when the intense acute transmural inflammation causes narrowing of the bowel lumen, during the chronic phase due to fibrotic stenosis, postoperative adhesions, incisional hernias, and exacerbation of the inflammatory condition (acute flare). Computed tomography is the imaging modality of choice to diagnose acute epiploic appendagitis, which is visualized as an ovoid, fat-attenuating pericolic mass situated along the antimesenteric border of the colon, ranging in size from 1 to 4 cm ( Fig. H. Pylori gastritis may be isolated to the antrum or greater curvature. A wide range of foreign bodies can cause SBO with variable imaging appearances. Small bowel hemorrhage can be the result of ischemia, trauma, vasculitis, coagulopathies, and anticoagulation therapy. Thumbprinting manifests as smooth, round, polypoid, and scalloped filling defects projecting into the colonic lumen, which correspond to thickened mucosal folds related to submucosal edema or hemorrhage. The term Ogilvie syndrome has been applied to both the acute and chronic forms of colonic pseudo-obstruction, though some authors believe this term applies to the acute form, which represents a reversible condition, associated with major surgery or severe medical illness. The gastric banding device is composed of the band itself, an access port, and connecting tube. The majority of cases involve the small bowel. A narrow pedicle can be formed leading to torsion of the loops and producing a small bowel volvulus. Although typically found in locally advanced gastric cancer, a focal ulcerated malignancy may perforate if the ulcer crater is deeply penetrating. Athul D. 16k watch mins. In early disease, mucosal edema and hyperemia are encountered, and with disease progression the mucosa develops punctate ulcers that enlarge and may extend into the lamina propria. However, because of its overlap with malignant causes of gastric outlet obstruction, exclusion of an underlying mucosal lesion is often warranted. Abscesses are identified as loculated low-attenuation fluid collections, possibly containing foci of air or an air-fluid level, with peripheral enhancement. In cases in which positive oral contrast agents are administered, opacification of the appendiceal lumen with oral contrast effectively excludes a diagnosis of appendicitis. The major advantage over endoscopy and classic barium studies is the assessment of extraenteric findings, which are relatively common in CD. Imaging Non-traumatic Abdominal Emergencies in Pediatric Patients is a very well-written book. The tract decompresses in the anatomic plane of least resistance, the most common being the plane located between the internal and external sphincters, extending into the ischiorectal fascia and to the perineal skin. On CT, gastric inflammation appears as low-attenuation submucosal edema and mucosal hyperemia, which result in mural stratification. During 2021 Radiopaedia.org will be organising a number of additional courses both in Australia and around the world. Role of radiology in Abdominal Emergencies. 13-21 ). Urgent surgery may be necessary when these complications develop. Ended on Aug 24, 2020. As previously discussed, attention to the degree of gastric distention helps discern true gastric wall thickening from artificial thickening resulting from collapsed lumen. Intussusceptions on CT typically demonstrate a targetlike appearance, with or without the presence of mesenteric fat or vessels, with the outer layer representing the intussuscipiens and the inner layer representing the intussusceptum ( Fig. It is a true diverticulum that contains all layers of the intestinal wall and has its own blood supply. Note the rich pattern of mucosal folds of the jejunum in the left upper quadrant, Causes of Small Bowel Obstruction in Adults, Axial computed tomography (CT) obtained after oral and intravenous contrast administration in a patient with history of treated lymphoma and suspected small bowel obstruction (SBO) shows evidence of complete bowel obstruction at the proximal jejunum, with absence of oral contrast beyond the transition point, Coronal unenhanced computed tomographic (CT) image demonstrates mottled material within the obstructed loop of proximal small bowel (“small bowel feces” sign), adjacent to the transition point, Unenhanced axial computed tomographic (CT) image obtained in an obese patient with abdominal pain and an unremarkable physical examination demonstrates a right paramedian ventral hernia containing a short segment of small bowel, Coronal contrast-enhanced computed tomographic images performed in a middle-age woman with diagnosis of ovarian cancer show multiple liver metastases, Coronal contrast-enhanced computed tomographic image obtained in a young woman with recurrent abdominal pain and gastrointestinal (GI) bleeding shows a long segment of jejunojejunal intussusception, Unenhanced axial computed tomographic (CT) image obtained at the level of the pelvis in a patient with typical features of small bowel obstruction (SBO) show an intraluminal mottled-appearing density causing significant distention of the bowel lumen at the transition point, consistent with an obstructing bezoar, Axial contrast-enhanced computed tomographic image performed in a patient with 3-day history of low-grade fever, abdominal pain, and diarrhea demonstrates diffuse mural thickening of a long segment of distal ileum associated with mucosal hyperenhancement and submucosal edema, as well as a moderate amount of free fluid. 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