Imaging of abdominal hernias.

Abdominal hernias are a common clinical problem. The main types of abdominal hernias are external or abdominal wall hernias, which involve protrusion of abdominal contents through a defect in the abdominal wall; internal hernias, which involve protrusion of viscera through the peritoneum or mesentery and into a compartment in the abdominal cavity; and diaphragmatic hernias, which involve protrusion of abdominal contents into the chest. Clinical diagnosis of abdominal hernias can be difficult. However, plain radiography, radiography performed after administration of barium, and computed tomography allow evaluation of suspected abdominal hernias and detection of those that are clinically occult. The anatomic location of the hernia, the contents, and complications such as incarceration, bowel obstruction, volvulus, and strangulation can be demonstrated with radiologic examination. Occasionally, complications such as neoplasms or inflammatory conditions can be identified in the hernial contents. With abdominal imaging modalities, a variety of abdominal hernias can be confidently diagnosed.

Metastatic disease involving the gastrointestinal tract.

Secondary involvement of the gastrointestinal tract by malignancies is encountered frequently. It usually reflects a poor prognosis because it is often multicentric and associated with metastases in other organs. Any therapy is usually palliative. Because of this, conventional barium studies or CT is sufficient for diagnosis and can obviate further studies.

Clinical significance of pneumatosis of the bowel wall.

The presence of gas within the bowel wall is an uncommon condition that is typically first diagnosed by the radiologist. Although it is often seen on abdominal radiographs, computed tomography is more sensitive in demonstrating pneumatosis and its complications. There is a spectrum of disease states that produce this abnormality, ranging from the innocuous to the fatal. Its radiographic appearance is variable, particularly the location, extent, severity, and presence of pneumoperitoneum or portal venous gas. None of these imaging characteristics can be considered pathognomonic for the underlying cause of the pneumatosis. The radiologist must be aware of the different conditions associated with this entity, as well as their variable appearances.

Angioimmunoblastic lymphadenopathy of the colon with malignant transformation.

Angioimmunoblastic lymphadenopathy (AILD) is a rare disorder characterized by lymphadenopathy, constitutional symptoms, skin rashes, and a variety of hematologic disorders. Its occurrence in the colon is rare. Late in the disease, immunosuppression occurs, and there is an increased risk of malignant transformation. We present a case of AILD of the colon with eventual transformation into malignant lymphoma.

Gastrointestinal carcinomas in renal transplant recipients.

The development of malignancies in renal transplant recipients is well documented. Typically, these are cutaneous tumors or lymphomas. During the past 5 years, we have encountered six patients with documented carcinomas of the gastrointestinal tract, which developed after these patients received renal transplants. These carcinomas developed at an average of 10 years (range 2-16 years) after renal transplantation. There were three carcinomas of the colon, and one each of the esophagus, stomach, and anal canal. In many instances, the patients had examinations prior to transplantation which were normal. Several surveys of transplant recipients indicate there is an increased incidence of gastrointestinal tract malignancies after transplantation. These studies also recommend that screening of the gastrointestinal tract in long-term transplant recipients be performed. Since these patients are often imaged in the radiology department, radiologists must be aware of this possible complication.

Nonspecific radiographic abnormalities in collagenous colitis.

Collagenous colitis (CC) is characterized clinically by a chronic, watery diarrhea. Pathologically, there is a chronic lymphocytic infiltrate with abnormal thickening of the subepithelial collagen layer. This disease occurs predominantly in females, and is more frequent in the elderly. Previous clinical studies suggest that radiographic examination of the colon is of no value in this condition. We reviewed five cases of CC all of whom had colon examination within 2 weeks of the biopsy. Two of our patients showed evidence of mucosal granularity and irregularity of the rectosigmoid on double-contrast barium enema (DCBE). One patient had nodularity of the rectal wall on single-contrast colon examination. Two patients had no inflammatory changes evident on colon examination. These radiographic changes are nonspecific and may be seen in other forms of colitis, particularly ulcerative colitis and nonspecific proctitis.

Digital radiography of the gastrointestinal tract.

The gastrointestinal tract lends itself quite well to digital imaging. Since fluoroscopy is already employed, the images can easily be obtained in digital format and several manufacturers have now developed systems for commercial use. Because of the type of pathology as well as the inherent subject contrast, it would appear the resolution requirements for digital imaging of the gastrointestinal tract are less than in other organ systems. The necessary resolution level is already technically available and feasible without significant cost. Digital imaging also holds promise of at least a modest reduction in radiation dose to the patient, as well as a reduction in costs, although these factors are operator dependent. However, digital imaging provides a latitude in performing the examination that is not available with screen-film systems. Finally, there is promise that by acquiring gastrointestinal images in digital format, manipulation of the images may help increase diagnostic accuracy by improving both technical and perceptive components of diagnosis. Not only will simple image manipulation be helpful but there is even potential for computer-assisted evaluation of gastrointestinal images.

Digital gastrointestinal imaging: the effect of pixel size on detection of subtle mucosal abnormalities.

Five radiographs of double-contrast colon examinations demonstrating subtle mucosal changes of inflammatory bowel disease and five radiographs of healthy colonic mucosa were selected and digitized to four levels of resolution. Pixel sizes of 0.1 mm, 0.2 mm, 0.4 mm, and 0.8 mm were used. Ten radiologists interpreted the images, which were displayed on laser-printed film. Analysis of variance with repeated measures was performed and receiver operator characteristic curves were determined. The results demonstrate that the sensitivity in detecting subtle mucosal abnormalities improved as the resolution improved, with the best sensitivity at the highest resolution; more experienced readers detected details well even at the poorer levels of resolution; the resolution necessary for successfully evaluating the colonic mucosa was lower than expected; and given low noise levels, the matrix size used in conventional television fluoroscopy would be adequate for mucosal evaluation.

Intestinal and extraintestinal complications of inflammatory bowel disease.

Inflammatory bowel disease has a variety of local and systemic complications that contribute to the morbidity and mortality associated with the disease. The radiologist plays an important role in the evaluation of these complications.

Malignancy complicating inflammatory bowel disease.

There is now general agreement that both ulcerative colitis and Crohn's disease predispose patients to the development of malignancy. Many controversies still remain concerning the incidence of this complication as well as the diagnostic approach to be taken with these patients. This article reviews the topic and examines the contribution the radiologist can make in evaluating the patient with chronic inflammatory bowel disease.

Reassessing the role of radiology in Hemoccult screening.

During a recent regional screening program, 98 patients with a positive Hemoccult test were evaluated radiographically. Double-contrast barium enema (DCBE) detected all six carcinomas and 92% of 37 polyps. DCBE was also the most cost-effective procedure. Colonoscopy dramatically increased screening costs without providing evidence to support its use in all Hemoccult-positive patients. It is recommended that DCBE be the initial diagnostic test in Hemoccult-positive patients, to be supplemented in selected patients by flexible sigmoidoscopy or colonoscopy depending on the pathology evident on DCBE and on clinical circumstances.

Changing concepts of colonic polyps: clinical and radiographic implications.

The relationship of colonic polyps to carcinoma of the colon provides a basis for their importance. Recent advances in the detection of colonic polyps, including double contrast barium examination and colonoscopy, have provided a method for more extensive study of colonic polyps. Studies using these newer techniques indicate that many traditional concepts of colonic polyps were inaccurate. The relationships of polyp size to histology, polyp location to age, and the phenomenon of colon polyp clustering are important to both the immediate treatment of the polyp and to the long-term follow-up of the patient. The use of hemoccult stool screening as a technique for screening for colonic pathology is also of significance to the radiologist. The changing relationships of various parameters of colon polyps bring into question the utility of many of the currently recommended screening procedures for colon pathology. Undoubtedly, this will impact on the practice of radiology.

Radiological assessment of dysphagia with endoscopic correlation.

Four hundred fifty consecutive patients with dysphagia were evaluated radiologically over a 14-month period; 127 of these (28.2%) were also examined endoscopically. The most common abnormality seen was dysmotility (34%), followed by hiatal hernia, benign stricture, and esophagitis. Correlation with endoscopy was generally good. Radiologic study demonstrated all cases of esophageal malignancy; radiologic/endoscopic correlation was also strong in patients with moderate or severe esophagitis, though the radiologist had some difficulty detecting mild inflammation. Endoscopy failed to demonstrate some benign strictures. Radiologic study was relatively accurate in detecting significant organic disease; most motility disorders were not detected by endoscopy. For these reasons, as well as lower cost, increased convenience, and patient comfort, radiologic assessment is recommended as the primary method of evaluating patients with dysphagia.

Crohn disease in the elderly.

During the past 2 years, we have encountered 14 patients whose onset of clinical symptoms of Crohn disease occurred after the age of 50, accounting for 14% of all Crohn disease patients studied in our department during this period. Most patients presented with diarrhea, abdominal pain, or perianal disease, and many also had anemia or rectal bleeding. The disease occurred slightly more often in the colon (n = 10), although many patients had terminal ileal disease (n = 7). The radiographic appearance was similar to that of Crohn disease in younger patients, with ulceration, fistula, and stricture formation. Occasionally, the disease mimics neoplasia or diverticulitis. Extraintestinal complications were also evident, with one patient each with renal calculi and ankylosing spondylitis. The occurrence of Crohn disease in the elderly is not uncommon, and a prompt diagnosis is important so that proper therapy can be initiated.

Gastric polyps: radiological evaluation and clinical significance.

Gastric polyps were found in 81 out of 4,692 consecutive radiological examinations (1.7%) and 103 out of 2,656 endoscopic examinations (3.9%) over a 19-month period. Polyps were more frequent in older patients and in women. Of 98 pathologically diagnosed lesions, 73 (74%) were hyperplastic and only two (2%) were adenomatous; most others were submucosal. Gastric polyps were rarely associated with carcinoma; only one patient had an area of severe dysplasia or carcinoma in situ, which was removed by polypectomy. The double-contrast technique had a high sensitivity and specificity in diagnosing gastric polyps. The location and number of lesions were relatively good indicators of pathology, but size and radiographic characteristics were not. The authors suggest that although radiology has a role in initial detection and screening, endoscopy should be the method of choice for further evaluation and follow-up. Histological identification is possible only with biopsy, and preferably polypectomy. The infrequent association with malignancy suggests that surgery is unnecessary in most cases.

Distribution of colonic polyps: increased incidence of proximal lesions in older patients.

Several recent studies have shown a proximal shift in the distribution of colonic carcinoma compared to older studies. Because of the association between polyps and cancer, the authors evaluated the distribution of colonic polyps in 3,664 consecutive patients who had a colon examination over a period of 14 months. A total of 967 colorectal polyps were found in 633 patients. In all, 502 polyps (52%) were proximal to the rectosigmoid. Older patients had significantly more right-sided polyps and fewer rectosigmoid lesions. Large polyps occurred more frequently in the right colon, and this was also statistically significant. Gender has no effect on polyp distribution. The authors conclude that the importance of screening for polyps, particularly on the right side of the colon, increases with age.