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.

CT of congenital and acquired abnormalities of the spleen.

Computed tomography (CT) is an excellent imaging modality for demonstrating the size, shape, and position of the spleen, as well as for depicting intrasplenic pathologic features. However, it has limited value in the diagnosis of splenic involvement by lymphoma. Greater accuracy in diagnosing splenic lymphoma may be obtained by demonstrating adenopathy in the splenic hilum or by showing focal splenic defects, in addition to splenomegaly. In discussing the normal anatomy of the spleen, congenital variations (eg, accessory spleen, polysplenia, asplenia, and wandering spleen), and acquired abnormalities such as those resulting from trauma, infection, infarction, cysts, and neoplasms, this article provides evidence that CT is valuable in showing a wide variety of splenic variations and abnormalities while simultaneously allowing evaluation of the remaining intraabdominal structures. The cases presented demonstrate both the value and limitations of CT in the examination of patients with congenital and acquired abnormalities of the spleen.

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.

Foregut ischemia and odynophagia in a patient with a type III aortic dissection.

We report a case of ischemia of the distal esophagus with secondary odynophagia that occurred as a result of a type III aortic dissection. A 56-yr-old hypertensive male presented with acute chest pain radiating to his back. A dissection of the descending aorta was found to begin just distal to the left subclavian artery and end in the region of the iliac arteries. The patient was treated medically and remained stable, but then developed odynophagia to solids. Upper endoscopy showed erythematous friable esophageal mucosa, and biopsies were consistent with ischemia. Aortography and barium fluoroscopy provided further evidence of foregut ischemia. The patient recovered on oral omeprazole with no residual symptoms. Ischemic compromise of the esophagus secondary to aortic dissection has not been previously described, nor have the associated endoscopic findings. Knowledge of this rare condition may help in the recognition and management of esophageal mucosal ischemia.

Endorectal sonography in the evaluation of rectal and perirectal disease.

Endorectal sonography initially was developed for evaluation of the prostate and now has been adapted for evaluation of rectal and perirectal disease. We used endorectal sonography to evaluate a spectrum of diseases, including primary and recurrent rectal carcinoma, metastases, villous adenoma, leiomyosarcoma, endometriosis, sacrococcygeal teratoma, chordoma, retroperitoneal cystic hamartoma, pelvic lipomatosis, diverticulitis, and perirectal abscess. The technique has been useful in localization of perirectal abscesses and in sonographically guided biopsy of perirectal masses. Knowledge of normal sonographic anatomy of the rectum is essential in the evaluation of rectal and perirectal disease. In this essay, we describe the technique of endorectal sonography and illustrate the sonographic findings in a variety of diseases.

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.

Computed tomographic evaluation and staging of cecal carcinoma.

The preoperative computed tomographic (CT) scans of 14 patients with biopsy-proven primary adenocarcinoma of the cecum were reviewed to assess clinical presentation, CT findings, and value of staging by CT. The correlation of CT evidence for tumor invasion beyond the bowel wall with histopathology had predictive value of negative examination of 33% with sensitivity of 78%. More importantly, the correlation of metastatic nodal involvement by CT had predictive value of negative examination of 22% with sensitivity of only 12%. Of chief concern was the involvement of pericolic and mesenteric nodal chains that were not discernible by CT. Computed tomographic tumor staging was accurate in 57% of cases and upgraded in 43%. This study concludes that, although predictive values of positive CT examination are high, CT tends to underestimate disease extent.