Typically MRI examinations in cases of suspected appendicitis include multiplanar T1- and T2-weighted sequences. Presenting signs and symptoms in patients with acute ischemic colitis include the acute onset of mild to severe crampy abdominal pain, nausea, and vomiting; bloody diarrhea and rectal bleeding may also occur several hours after the onset of abdominal pain. CLINICAL APPLICATIONS. However, the converse does not hold true, and a lack of appendiceal opacification with oral contrast material does not definitively indicate a diagnosis of acute appendicitis because this is often the case with normal appendices. Many traditional emergency imaging procedures have been replaced with newer helical CT techniques that can be performed in less time and with greater acc … Radiology . Patients with decreased gastric motility, such as those who have undergone gastric surgery, are predisposed to formation of phytobezoars, which may also pass into the small bowel and cause obstruction more distally as well. The small bowel has a central location in the abdomen. This three-day course is designed to provide the practicing radiologist an intensive hands-on experience in imaging interpretation of traumatic and non-traumatic emergencies. The presence of tachycardia, rebound tenderness, and severe abdominal pain are predictors of poor outcome. Acute diverticulitis represents the most common cause of vesicocolonic fistulas, which often occur along the left posterolateral aspect of the bladder in cases of sigmoid diverticulitis and may be suspected based on the presence of intravesicular air and focal bladder wall thickening adjacent to an inflamed diverticulum. In cases of suspected ischemic colitis the mesenteric vessels should be closely scrutinized for obstructing arterial or venous thrombi. Protocols are variable but generally include multiphasic coronal fluid-sensitive sequences. Small bowel obstruction (SBO) and inflammation are common conditions, often presenting with nonspecific signs and symptoms, similar to those seen in other acute abdominal disorders. Fatty infiltration of the bowel wall may occur in chronic IBD and was thought to be pathognomonic of this disease. 13-14 ). In the assessment of small bowel disease, CT enterography, with negative or neutral oral contrast material, can be used to achieve bowel distention and to improve evaluation of bowel wall morphologic characteristics, thickness, and enhancement. Appendectomy is the treatment of choice in simple acute appendicitis, and laparoscopic appendectomy is increasingly common. The presence of “skip lesions” is one of the hallmarks of the disease. Other common pathogens that often affect the small bowel, typically the distal ileum and cecum, include Yersinia , Campylobacter , and Salmonella species ( Fig. Abdominal Imaging & Emergency Radiology Radiology expert witness. Adhesions are the most common cause of SBO in the United States, ranging from 50% to 80% of cases. Small bowel obstruction occurs in the late phase of radiation enteritis, most often in the distal small bowel as a result of adhesive and fibrotic changes that develop several months after therapy. Additional findings include pseudosacculations or pseudodiverticulum formation, which occur as a consequence of relative sparing of the antimesenteric border within an affected segment. Both a normal white blood cell count and body temperature are commonly found, and constitutional symptoms such as nausea, vomiting, and anorexia are uncommon. As opposed to sigmoid volvulus, in which the cause is usually acquired, the most common predisposing factor to cecal volvulus is an abnormal embryologic connection of the right colon to retroperitoneum resulting in increased mobility of the cecum. More specific findings include absent, asymmetric, or delayed bowel wall enhancement, with or without focal mesenteric fluid or hemorrhage ( Fig. Computed tomography also is useful for accurately depicting the degree of colonic distention that may warrant surgical decompression. In the setting of ischemic colitis, pneumatosis intestinalis or the presence of portomesenteric venous air is highly suggestive of frank bowel wall necrosis. Vomiting usually occurs in late stages of disease when abdominal distention is severe. In abdominal emergencies there is no indication of an immediate abdominal CT scan. Bacterial causes of infectious colitis include Salmonella , Shigella , Campylobacter , Yersinia , Staphylococcus , E. coli (O157:H7), Staphylococcus , and Clostridium difficile . Complications of CD include abscesses, fistula formation, anal fissures, and colon cancer. 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. 13-25 ). Angioedema is not a true inflammatory disease, but it can mimic inflammation because it presents with bowel wall thickening. During 2021 Radiopaedia.org will be organising a number of additional courses both in Australia and around the world. When bowel motility is affected by mechanical obstruction or nonobstructive adynamic ileus, gas accumulates within the small bowel. 13-36 ). The port is usually placed outside the peritoneal cavity, either within the rectus abdominis muscles sheath or under the external thoracic fascia. An inflammatory tract develops between a primary internal opening in the anal crypt at the dentate line and extends to a secondary external opening in the perianal skin. Patients with epiploic appendagitis typically present with an acute onset of abdominal pain with localized tenderness over the portion of the affected colon with the left lower quadrant being the most commonly affected site. Contrast-enhanced CT is the imaging modality of choice to evaluate the bowel in cases of suspected intussusception. Sigmoid volvulus represents torsion or twisting of the sigmoid colon around the mesenteric axis. 13-31 ). Although no underlying mechanical obstruction exists, Ogilvie syndrome is a significant cause of morbidity and death with possible progression to bowel ischemia and perforation. On CT, abnormally increased mucosal and serosal enhancement of affected colonic segments, bowel wall thickening, and ascites are suggestive of infectious colitis ( Fig. The layers of the visceral peritoneum encase the small bowel and associated mesentery. Diagnostic workup often starts with radiography, particularly if the ingested item is radiodense (e.g., metallic) or suspected to be lodged in the hypopharynx. Abdominal emergencies usually present with abdominal pain in association with other signs and symptoms. Special Section on Dual Energy CT. February 2017, issue 2. It is characterized by episodes of increased capillary permeability, with extravasation of intravascular fluid and subsequent edema of the skin, mucosa of the upper airways, or GI tract. Computed tomography may readily identify complications, including bowel ischemia or perforation. Up to one third of affected adult patients with foreign body impaction have an underlying esophageal stricture contributing to their presentation. 13-1 ). Whipple disease is a rare multisystemic bacterial infection caused by the Whipple bacillus (Tropheryma whipplei) , involving the small bowel (particularly the jejunum), lymph nodes, joints, and central nervous system. Unable to process the form. Weight loss, malabsorption, and perianal fistulas and fissures are also frequently observed. These are more commonly chronic and less likely to be associated with diaphragmatic hernias. Peptic ulcer disease, trauma, and iatrogenic causes lead the list of potential causes of duodenal perforation. With disease progression the bowel wall thickens and becomes featureless due to the loss of haustral folds. The imaging features of the “Rigler triad” include SBO, an ectopic gallstone, and pneumobilia because a cholecystenteric fistula is needed for the migration of a large obstructing gallstone to occur ( Fig. In addition, depending on the underlying cause, air-fluid levels, pericolic inflammation, and mesenteric lymphadenopathy may also be visualized on CT in cases of infectious colitis. The epiploic appendages may become inflamed or torsed, resulting in infarction. Superficial tears, or Mallory-Weiss tears, commonly result from repeated, forceful retching and may cause “coffee-ground” emesis caused by mucosal bleeding. 13-22 ). Complications are more common in jejunoileal diverticula than duodenal diverticula and, similar to their colonic counterpart, include bleeding, intestinal obstruction, and diverticulitis. As opposed to ulcerative colitis (UC), rectal involvement is very rare in CD. The major clinical manifestation of jejunoileal diverticula is malabsorption. Esophagitis can arise from a number of causes, including infection, radiation, gastroesophageal reflux, and medications. Therefore C. difficile colitis often occurs 4 to 9 days after the initiation of antibiotics. The findings that indicate strangulation include bowel wall thickening and hyperattenuation, a halo or target sign, mesenteric fat stranding and/or fluid, pneumatosis intestinalis, and mesenteric or portal venous gas, but these findings are not entirely specific. MECCSIG Members. It is the result of migration of a gallstone into the small bowel with subsequent impaction, most often at the ileocecal valve. The jejunum and ileum are mobile and intraperitoneal organs, attached to the posterior abdominal wall by the mesentery, which contains fat and provides the vasculature and lymphatics to the small bowel. The upper gastrointestinal (GI) tract, including the esophagus, stomach, and duodenum, is a common but potentially overlooked site of disease that may prompt presentation to the emergency department (ED), including inflammation and infection, obstruction, and perforation. Progressive narrowing of the afferent and efferent limbs of colon is seen, leading to a whirl sign, which represents a tight twisting of the mesentery and “beaking” due to tapered narrowing of the afferent and efferent bowel loops. If you are from a low or middle-income region you may be eligible for free access to all Radiopaedia.org courses. 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. Most often, an adhesion or hernia will cause partial or complete occlusion of a segment of bowel loop at two adjacent points. The organism tends to inhabit the duodenum and jejunum. Despite abundant research in this field, it remains a diagnostic and therapeutic challenge. Magnetic resonance enterography is an attractive modality for the assessment of CD because it can offer dynamic evaluation of bowel motility, superior soft tissue contrast, and excellent depiction of fluid and edema, without associated ionizing radiation. Over 6 hours of on-demand video. However, CT and MRI can depict several abnormalities that are associated with acute bowel inflammation, such as mural thickening and stratification, thickened folds and/or reduction or distortion of folds due to ulceration and cobblestoning. Any part of the GI tract may be involved, from the mouth to the anus, and the disease process is commonly discontinuous. Colonoscopy with the retrieval of multiple biopsy specimens is the first-line study for diagnosing this disease. In the setting of SBO, it can be performed without oral contrast administration, because the retained intraluminal fluid serves as a natural negative contrast agent (and delays transit of any ingested contrast). This type of gastric volvulus is more commonly associated with diaphragmatic defects and vascular compromise. Whereas superficial ulcers can be seen only with endoscopy or with barium fluoroscopy, deeply penetrating ulcers may be identified on CT as a focal mucosal outpouching, submucosal edema, perigastric fat stranding, and in the case of perforation, extraluminal gas ( Fig. 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 sequelae of acute ischemic colitis include reversible ischemic colitis, chronic ulcerative ischemic colitis, ischemic colonic stricture, or colonic necrosis with perforation and sepsis. 13-46 ). Computed tomography is the imaging study of choice. Patients with UC usually present with bloody diarrhea, passage of mucus, abdominal pain, tenesmus, and urgency of defecation. Overall the most common causes of toxic megacolon are C. difficile and UC. Gastrointestinal involvement sometimes mimics an acute abdomen or rarely can cause life-threatening hypovolemic shock. Click on the volume number you want transferred to your PC. Acute disorders of vascular origin, such as acute hemorrhage, ischemia/infarction, and vasculitis are discussed in the nontraumatic vascular emergencies section. In addition to benign causes, primary or metastatic esophageal tumor may also perforate, particularly following palliative dilatation and/or stenting. 13-40 ). Special Section: Distinguished reports from the Japanese Society of Abdominal Radiology (JSAR) June 2017, issue 6; May 2017, issue 5; April 2017, issue 4. Imaging is reserved for cases in which blood and stool cultures are negative and in cases of failed colonoscopies. 13-20 ). Less common signs and symptoms include nausea, vomiting, constipation, and urinary symptoms. 13-57 ). Crohn disease is part of the IBD spectrum, characterized by chronic, relapsing inflammation of unknown cause. Inflammatory bowel disease and infectious enteritis can have similar imaging findings, with distinction made based on the clinical history, as well as the distribution of findings within the bowel. In the setting of severe stenosis or occlusion of the mesenteric arterial or venous supply, bowel ischemia can lead to significant bowel wall thickening, resulting in SBO. In cases in which positive oral contrast agents are administered, opacification of the appendiceal lumen with oral contrast effectively excludes a diagnosis of appendicitis. Large bowel intussusception is commonly associated with lead points. In pregnancy, intravenous gadolinium should not be administered for this application and the utility of oral contrast is a subject of ongoing investigation. Available ONLY to: UQMS Members The treatment of Ogilvie syndrome is based on the clinical and imaging assessment and includes supportive treatment, endoscopic decompression, and surgical decompression. Computed tomography findings include long segment thickening of the esophageal wall (greater than 5 mm), as well as a “target” sign caused by mucosal hyperemia and submucosal edema ( Fig. 13-43 ). In contrast to peptic ulcers in the stomach, duodenal ulcers have very low malignant potential and typically occur because of increased peptic acid secretion, including in the setting of chronic H. pylori infection. Characteristic findings include duodenitis with dilution, slow transit, and flocculation of oral contrast, small bowel dilation, transient small bowel intussusception, villous atrophy and reversal of the fold pattern, with jejunization of the ileum, as reflected by a decrease in normal jejunal folds in contrast to the increasing fold pattern in the ileum. Special Section on Celiac Disease. 13-10 ). A definite diagnosis can be confirmed by elevated serum levels of C4 and C1 esterase inhibitor and C1 esterase inhibitor functional activity complement levels ( Fig. Closed-loop obstruction can result ( Fig. After gastric adenocarcinoma the second most common tumor to obstruct the stomach and/or duodenum is pancreatic head adenocarcinoma, which can cause gastric outlet obstruction in 15% to 25% of cases. Common predisposing factors for ileus include sepsis, electrolyte disturbances, GI infection, and recent surgery. Similar to those with aortoesophageal fistulas, affected patients may have a “herald bleed” preceding life-threatening voluminous hemorrhage. Esophageal obstruction by a malignant stricture usually manifests with short segment involvement and mucosal shouldering on fluoroscopy. Although imaging findings are often nonspecific, including mural thickening, mesenteric fat stranding, and moderate mesenteric lymphadenopathy, the clinical history and distribution can be helpful in narrowing the differential diagnosis. 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. Like CD elsewhere in the GI tract, gastroduodenal involvement may be complicated acutely by obstruction, perforation, abscess, and fistula formation. The cause and pathophysiologic process of intussusception are not well understood, particularly intussusception without a lead point. Crohn disease is more common in white and Jewish populations and in northern Europe and North America and typically occurs in the second and third decades of life, affecting both sexes equally. Acute colonic obstructions are emergencies requiring early detection to prevent complications such as perforation or ischemia. On imaging this appears as narrowing of the affected segment with associated soft tissue thickening, most often the pylorus. 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. A high degree of clinical suspicion is needed, particularly in patients using angiotensin-converting enzyme inhibitors and a variety of other medications, in the setting of typical imaging findings. Similar to peptic ulcer disease in general, the incidence of gastric outlet obstruction due to peptic ulcer disease is decreasing. Metastatic involvement is far more common than primary disease. Adhesions can be differentiated from fistulas because they are fibrotic and tend to be thinner and enhance later. Online case-based review of abdominal emergency radiology featuring over 6 hours of video recordings by Dr Vikas Shah, Dr Jeremy Jones and Dr Andrew Dixon. Cryptosporidium is a GI parasite that results in watery diarrhea in patients with acquired immunodeficiency syndrome (AIDS). Corresponding submucosal soft tissue attenuation can be seen on CT, which may also demonstrate invasion into the adjacent mediastinum and mediastinal lymphadenopathy in advanced disease. There is a large overlap in the CT appearance of infectious and noninfectious esophagitis, such as from reflux or radiation. Freed will thoroughly review all imaging aspects of your case and correlate with clinical history made available to the interpreting radiologist at the time of imaging. The jejunum is located more proximal (and superior), with larger caliber, thicker folds, and greater vascularity than the jejunum. The fundus is the most dependent portion of the stomach and is subsequently the most common site for layering intraluminal contents, notably blood products. Larger ulcers are seen with cytomegalovirus and human immunodeficiency virus (HIV) esophagitis. Radiation-induced enteropathy has distinct acute and chronic manifestations. Gastritis has many potential underlying causes, including Helicobacter pylori infection, nonsteroidal antiinflammatory medications, and alcohol. 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. Mesenteroaxial gastric volvulus is less common and results from rotation of the stomach about its short axis, resulting in the antrum being positioned above the gastroesophageal junction ( Fig. On unenhanced CT examinations, a thickened appendix with surrounding inflammatory changes, with or without a calcified appendicolith (see Fig. However, oral contrast delays the diagnosis in the emergency setting and is generally not tolerated by obstructed patients presenting with nausea and vomiting. Mural stratification with a target appearance consisting of intense enhancement of the mucosa, hypoattenuation of the submucosa, and an outer enhancing muscularis propria may be identified (see Fig. Ulcerative colitis is also associated with extraintestinal manifestations, similar to those seen in CD. The majority of cases involve the small bowel. March 2017, issue 3. 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