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.

Radiologic evaluation of constipation and anorectal disorders.

This article has outlined the orderly radiographic approach to evaluating the patient who presents with constipation or other anorectal complaints. Defecography alone provides only a visual record of events taking place during defecation, and it seems likely that further understanding of the pathophysiology will require manometric, electromyographic, and proctographic data in those patients. Defecography is potentially more available than these other techniques because every hospital has a fluoroscopy suite. Studies that relate the proctographic findings with other physiologic studies are underway and necessary. More studies relating pre- and postoperative defecography with clinical results are needed.

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.

Increased frequency of reactions to contrast materials during gastrointestinal studies.

Although there have been several reports of adverse reactions to contrast material during barium gastrointestinal (GI) studies, these are considered highly unusual. During a 27-month period at the author's institution, seven reactions to contrast material occurred during 6,918 colon examinations, and four reactions to contrast material occurred during 11,534 upper GI procedures. This frequency is greater than what has been reported previously. Most reactions were fairly mild, with urticaria and pruritus, although two patients, both with a history of asthma, had severe reactions that required emergency treatment. One patient had similar adverse reactions during both upper and lower GI examinations. Since only two patients received glucagon, this is not believed to be a factor. It is likely that patients react to some additive in the barium suspension. The radiologist must be aware of these complications and be ready to begin appropriate treatment.

Evolution of the technologist specialist in gastrointestinal radiology.

Over the past few years, a program was initiated at the author's institution to train radiologic technologists to perform the fluoroscopic aspect of gastrointestinal examinations. The program was undertaken in an attempt to improve patient flow through the division, as well as in response to the decreasing number of residents being accepted into the radiology program. The results with respect to diagnostic quality of examination, improved patient flow, and patient and resident acceptance have been satisfactory.

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.

Acute diverticulitis in patients under 40 years of age: radiologic diagnosis.

During a 4-year period, eight patients 40 years old or younger had surgically proved diverticulitis at our institution. None of these patients had connective-tissue diseases or were on medication (i.e., steroids) that would predispose them to diverticulosis. The presenting clinical symptoms in this group of patients were often misleading, and in only one of the eight cases was the correct clinical diagnosis made at the time of admission. Of the three diagnostic studies that were performed (barium enema, sonography, and CT), barium enema was the most accurate, yielding evidence for diverticulitis in six of seven cases. The degree and extent of diverticulosis in these patients was minimal compared with that in the older patients. CT showed abdominal abscesses in two patients; in one, a mistaken diagnosis of Crohn disease was made; in the other, diverticulitis was correctly identified. In the three patients in whom sonography was performed, the findings were negative for diverticulitis. Our experience suggests that the diagnosis of acute diverticulitis should be considered in patients with abdominal pain who are less than 40 years old.

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.

Limiting overhead views in double-contrast colon examinations does not affect diagnostic accuracy.

A prospective study was undertaken to evaluate whether reducing overhead (technician-performed) films in double-contrast colon examinations had any effect on diagnostic accuracy. Only 4 overhead films were obtained routinely: supine, both decubitus, and prone cross-table rectal views. A high detect rate was maintained, comparable to our accuracy when 7 or 8 overhead films were obtained. Our study confirms that with double-contrast colon examinations, the need for overhead films is diminished. A significant decrease in cost, radiation exposure, and examination time can be obtained. We continued to use this method without any noticeable decrease in diagnostic accuracy.

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.