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Polyposis Syndromes

The polyposis syndromes are rare conditions characterized by gastrointestinal (GI) polyposis resulting from specific genetic mutations. A thorough knowledge of the clinical and radiographic manifestations of these syndromes and their complications is required to provide optimal care for affected individuals and their families. Familial Adenomatous Polyposis Syndrome Familial adenomatous polyposis syndrome (FAPS) is a group of related disorders caused by a mutation of the adenomatous polyposis…

Other Tumors of the Colon

This chapter discusses a variety of benign and malignant tumors of the colon as separate entities. Although these tumors are associated with a wide range of clinical and radiologic manifestations, they may have typical features on imaging studies that suggest the correct diagnosis. Lymphoma PATHOLOGIC FINDINGS Malignant lymphomas involve the gastrointestinal (GI) tract as primary neoplasms or as part of a disseminated disease. The colon is…

Polyps and Colon Cancer

Epidemiology Colon cancer is a major public health problem in the United States. As a cause of cancer mortality, it ranks third to prostate and lung cancer in men and breast and lung cancer in women. The American Cancer Society estimates that in the year 2019 about 145,600 persons will be diagnosed with colorectal cancer and that about 67,100 will die of the disease. The distribution…

Other Inflammatory Conditions of the Colon

Infectious and inflammatory disorders of the colon are common and do not require imaging in most cases. In some disorders, imaging has a role in establishing the diagnosis, assessing the severity of the process, monitoring the course of the disease, and determining the presence of complications. Bacterial Infections Infectious colitis may be caused by bacterial, viral, fungal, and parasitic organisms. In Western countries, bacterial colitis represents…

Ulcerative and Granulomatous Colitis: Idiopathic Inflammatory Bowel Disease

The term inflammatory bowel disease (IBD) encompasses two forms of chronic, idiopathic intestinal inflammation, ulcerative colitis and Crohn’s disease. Although many other inflammatory diseases affect the gut, most are distinguished by a specific identifiable causative agent or process or by the nature of the inflammatory activity. The cause of ulcerative colitis and Crohn’s disease is unknown, so these disorders are empirically defined by their typical pathologic,…

Diseases of the Appendix

The vermiform appendix is the smallest segment of the gastrointestinal (GI) tract and the least relevant to its function, yet diseases of the appendix are among the most common surgical emergencies in the Western world. Anatomy The appendix arises anywhere along the medial-posterior wall of the cecum between the ileocecal valve and the cecal tip ( Figs. 40.1 and 40.2 ). A fully developed appendix varies…

Diverticular Disease of the Colon

Colonic diverticula are acquired herniations of the mucosa and of portions of the submucosa through the muscularis propria. Diverticular disease of the colon represents a continuum from an initial, prediverticular phase of marked muscular thickening of the colon wall (myochosis) to frank outpouchings (diverticulosis) and finally to diverticular perforation (diverticulitis). Disease progression from the initial phase to the advanced phases does not necessarily occur. In this…

Computed Tomography Colonography and Evaluation of the Colon

Computed tomography colonography (CTC) is a low-dose, cross-sectional imaging examination optimized for the detection of colorectal polyps and masses. As a result of advanced computer three-dimensional (3D) post-processing, a popular misperception is one of an imaging analogue to optical colonoscopy in which a 3D model alone is used to view the mucosal surface of the colon. However, CTC is fundamentally a different examination, using both 2D…

Functional Imaging of Anorectal and Pelvic Floor Dysfunction

Pelvic floor disorders are an underdiagnosed source of morbidity and significantly diminish the quality of life. Most patients are women. In any clinic that deals with pelvic floor disorders, about 80% of patients will be women between the ages of 35 and 50 years. Pelvic floor disorders are seen less frequently in men. The demand for pelvic floor imaging is increasing. There are several factors that…

Barium Studies of the Colon

Barium enemas are not commonly performed in modern radiology practice because of greater use of other diagnostic tests such as colonoscopy, computed tomography (CT), and, most recently, CT colonography. As senior radiologists retire, it has become increasingly difficult for young radiologists to acquire the expertise needed to capably perform and interpret these studies. Nevertheless, barium enemas can still be useful for evaluating patients with a variety…

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…