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Miscellaneous Abnormalitiesof the Small Bowel

Abnormalities of Small Bowel Development in Adults MECKEL’S DIVERTICULUM During embryologic development, the yolk sac is connected to the midgut by the omphalomesenteric duct, which is later obliterated during the seventh to eighth weeks of embryogenesis. Persistence of the entire omphalomesenteric duct results in an enteroumbilical fistula; persistence of part of the duct results in an omphalomesenteric cyst; persistence of the duct as a fibrous cord…

Postoperative Small Bowel

Surgical treatment of small bowel disease requires the use of relatively few surgical techniques, and most are applicable to any segment of the jejunum and ileum. These techniques include enterotomy for removal of polyps or foreign bodies; enteroplasty for treatment of strictures; enterectomy for resection of obstructed, traumatized, neoplastic, or necrotic small bowel; plication to prevent intestinal obstruction, and creation of ostomies or mucous fistulas for…

Vascular Disorders of the Small Intestine

Small bowel abnormalities continue to be a significant diagnostic challenge for clinicians and radiologists. Clinicians have historically struggled to diagnose many small bowel diseases because patients typically present with only nonspecific complaints such as abdominal pain, weight loss, or anemia. Therefore, in most cases, the diagnosis of small bowel pathology is highly dependent on the radiologist. Although fluoroscopic barium studies have traditionally been the mainstay in…

Small Bowel Obstruction

In patients with known or suspected small bowel obstruction (SBO), the radiologist is called on to answer the following questions: Is the bowel obstructed? If so, what is the level of obstruction? What is the cause of obstruction? What is the severity of obstruction? Does the patient have a closed loop or simple obstruction ( Fig. 32.1 )? Is the bowel strangulated? Are ischemic changes present?…

Malignant Tumors of the Small Bowel

Primary small bowel malignancy accounts for 0.6% of all new cancer cases, and 0.2% of cancer deaths in the United States. Despite the low incidence relative to other malignancies, the incidence of small bowel malignancy has been increasing from 1.1 per 100,000 persons in 1975 to 2.5 per 100,000 persons in 2015, largely owing to the increasing incidence of neuroendocrine tumor (NET) and duodenal adenocarcinoma. Only…

Benign Tumors of the Small Bowel

Clinical Considerations Despite a wide variety of histologic types, benign and malignant tumors of the small bowel constitute only 1% to 5% of all gastrointestinal (GI) neoplasms. , Nearly 75% of small bowel tumors discovered at autopsy are benign, while most found at surgery in symptomatic patients are malignant neoplasms. When diagnosed antemortem, benign small bowel tumors are usually found during the sixth to eighth decades…

Malabsorption

Anatomic Classification of Malabsorption Carbohydrate digestion requires a functioning pancreas and small bowel brush border enzymes. Normal protein digestion requires adequate gastric and pancreatic function and small bowel brush border enzymes. Fat digestion requires normal hepatic, biliary, exocrine, pancreatic, and small bowel function. An anatomic classification of malabsorption based on abnormalities of the liver, biliary tree, pancreas, stomach, and small intestine aids the radiologist in understanding…

Other Inflammatory Conditions of the Small Bowel

The radiologist usually encounters infectious disease of the small intestine during the workup of patients with acute abdominal pain or diarrhea or with chronic diarrhea, malabsorption, and weight loss. If computed tomography (CT) reveals thickened ileal folds or regional mesenteric adenopathy in patients with acute symptoms, various infectious pathogens (e.g., Yersinia ) should be considered ( Fig. 28.1 ). Stool cultures and biopsy specimens often fail…

Crohn’s Disease of the Small Bowel

Clinical Considerations Crohn’s disease is an idiopathic inflammatory disease that can affect any part of the gastrointestinal (GI) tract from the mouth to the anus. Patients with this disease have a genetic predilection to an abnormal immunologic response to environmental factors, including food, and gut flora leading to a chronic inflammatory response. The small bowel is the major site of involvement. With the exception of malignant…

Magnetic Resonance Enterography

Small bowel radiology has undergone dramatic changes in the past two decades. Despite recent advances in small bowel endoscopy and video capsule technology, radiologic imaging remains an important means of evaluating patients with suspected or established small bowel disease. Cross-sectional imaging techniques are used to investigate extraluminal abnormalities and intraluminal changes and have gradually replaced barium contrast examinations for many indications. Magnetic resonance imaging (MRI) has…

Computed Tomography Enterography

Computed Tomography Enterography: How It Differs From Routine Abdominal Computed Tomography Computed tomography enterography (CTE) reflects individualization of the abdominal pelvic CT technique for patients with small bowel disorders. CTE provides visualization of the small bowel lumen, wall, and perienteric tissues by distending the small bowel with large volumes of oral contrast and obtaining multiplanar, high-resolution images of the bowel during appropriate phase(s) of enhancement. It…

Barium Studies of the Small Bowel

Normal Small Intestine The small intestine is extremely tortuous, beginning at the pylorus and extending about 11 feet in the living human from the pylorus to the ileocecal valve. Intestinal length is extremely variable, depending on neuromuscular tone and vascular flow. For example, the denervated, bloodless intestine stretched at autopsy varies from 10 to 30 feet in length. A patient with a small bowel obstruction will…

Postoperative Stomach and Duodenum

Gastroduodenal surgery is often performed for severe peptic ulcer disease (PUD), benign or malignant neoplasms, and obesity. Radiologic evaluation of the postoperative stomach and duodenum requires an understanding of the surgery performed, expected postoperative appearances, and potential complications. During the early postoperative period, the radiologist is often asked to evaluate the surgical anatomy and to assess for complications such as leaks. During the late postoperative period,…

Miscellaneous Abnormalities of the Stomach and Duodenum

Gastric Varices Pathophysiology Portal Hypertension The gastric fundus is normally drained by numerous short gastric veins that anastomose distally with the splenic vein and proximally with the coronary vein and venous channels surrounding the distal esophagus. The short gastric veins normally empty via the splenic vein into the portal vein. In portal hypertension, however, increased pressure in the portal and splenic veins leads to reversal of…

Other Malignant Tumors of the Stomach and Duodenum

Metastases Gastric and duodenal metastases are found at autopsy in less than 2% of patients who die of carcinoma. Most of them are blood-borne metastases, but the stomach and duodenum are also involved by lymphatic spread or by direct extension of tumor from neighboring structures or mesenteric reflections such as the gastrocolic ligament, transverse mesocolon, and greater omentum. CLINICAL FINDINGS Many gastric and duodenal metastases are…

Carcinoma of the Stomach and Duodenum

Gastric Carcinoma EPIDEMIOLOGY Gastric carcinoma has striking geographic variations, with the highest reported incidence in Japan. However, Japanese who migrate to the United States have a significantly lower incidence of gastric cancer than those living in Japan, so other factors such as diet and Helicobacter pylori infection are thought to play a major role in the development of this tumor. Other predisposing conditions include atrophic gastritis,…

Benign Tumors of the Stomach and Duodenum

Between 85% and 90% of neoplasms in the stomach and duodenum are benign. About 50% are mucosal lesions and 50% are submucosal. Most benign neoplasms are discovered fortuitously on barium studies or endoscopy, but large or ulcerated tumors may cause abdominal pain or upper gastrointestinal (GI) bleeding. Others are important because of the risk of malignant degeneration. Mucosal Lesions Polyps constitute about 50% of benign neoplasms…

Inflammatory Conditions of the Stomach and Duodenum

Erosive Gastritis Erosions are defined histologically as epithelial defects that do not penetrate beyond the muscularis mucosae. Although gastric erosions are rarely diagnosed on single-contrast upper gastrointestinal (GI) studies, they are detected on double-contrast studies in 1% to 20% of patients. PATHOGENESIS Erosive gastritis is most commonly caused by aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs). Other less frequent causes include alcohol, stress, trauma, burns, Crohn’s…

Peptic Ulcers

Gastric or duodenal ulcers (peptic ulcers) are thought to occur in about 10% of adults in the West. Peptic ulcers are important not only because of the frequent occurrence of pain or other symptoms but also because of the morbidity and mortality associated with complications such as bleeding and perforation. Epidemiology and Pathogenesis Duodenal ulcers are more common than gastric ulcers, occurring in adults of all…

Postoperative Esophagus

General Principles Radiologic evaluation of the postoperative esophagus requires an understanding of the operative procedures and normal postoperative findings. Radiographic studies are performed in these patients for three general purposes: (1) to define the postoperative anatomy and establish a baseline; (2) to assess the efficacy of the procedure; and (3) to detect complications during the early (<4 weeks after surgery) or late (>4 weeks after surgery)…