CHAPTER 86
Plain and contrast radiology

Stephen E. Rubesin and Marc S. Levine

Hospital of the University of Pennsylvania, Philadelphia, PA, USA,

Plain radiographs of the abdomen are useful for evaluating abdominal pain or distension, obstructive symptoms, or clinical signs of an acute abdomen. The combination of supine and upright or decubitus horizontal beam radiographs allows the diagnosis of adynamic ileus or obstruction of the small bowel or colon, free intraperitoneal air (pneumoperitoneum) (Figure 86.1), ischemic or necrotic bowel with air in the bowel wall (pneumatosis) (Figure 86.2), air in the bile ducts (pneumobilia), and portal venous gas (Figure 86.3). Nevertheless, computed tomographic (CT) scanning is a more sensitive modality for evaluating acute abdominal symptoms (see Chapter 89).

Double‐contrast radiography is a valuable technique for diagnosing a wide spectrum of pathological processes in the gastrointestinal tract. Because this technique can delineate normal mucosal surface patterns in the pharynx, upper gastrointestinal tract, small bowel, and colon, it is particularly helpful in detecting a variety of inflammatory or neoplastic diseases involving the mucosa. In some cases, barium studies may demonstrate abnormalities that are missed or misinterpreted at endoscopic examination. Double‐contrast radiography and endoscopy should be considered as complementary procedures for evaluating suspected gastrointestinal disease.

Double‐contrast radiography can delineate in detail the normal anatomical features of the pharynx (Figure 86.4). As a result, inflammatory (Figure 86.5) or neoplastic (Figures 86.6 and 86.7) lesions that disrupt or obliterate the normal anatomical landmarks can be demonstrated readily. In the upper gastrointestinal tract, double‐contrast techniques allow detection of esophagitis caused by plaques or ulcers (Figure 86.8), esophageal cancer (Figure 86.9), benign gastric ulcer (Figure 86.10), early gastric cancer (Figure 86.11), duodenal ulcer (Figure 86.12), erosive gastritis or duodenitis, and other inflammatory or neoplastic lesions. Today, most upper gastrointestinal series are used to demonstrate preoperative and postoperative anatomy, to explain severe symptoms (Figure 86.13) and demonstrate complications, such as leaks (Figure 86.14). Single‐contrast techniques demonstrate motility and the big picture better than double‐contrast studies (Figure 86.15).

The small bowel follow‐through examination can determine the site and cause of small bowel obstruction (Figure 86.16) and a variety of other abnormalities in the small bowel (Figures 86.17 and 86.18). Although double‐contrast barium enema examination is a valuable technique for detecting colonic polyps or carcinoma or inflammatory bowel disease, it has largely been replaced by endoscopy or virtual colonoscopy. Double‐contrast barium enema is still a relatively inexpensive and safe examination that provides a detailed examination of the colon (Figure 86.19). Single‐contrast water‐soluble enemas remain valuable to exclude leaks. Single‐contrast barium enemas are still used in debilitated patients and to exclude obstruction or fistula formation (Figure 86.20).