Closed-loop and strangulating intestinal obstruction: CT signs.

In 19 patients with closed-loop intestinal obstruction, including 16 patients with strangulating obstruction, the findings at examination with computed tomography (CT) were retrospectively correlated with the surgical and pathologic findings and evaluated by two radiologists. Signs of closed-loop obstruction, present in 15 patients, were associated with the configuration of the incarcerated loop of small bowel, abnormalities detected at the site of obstruction, or both. These abnormalities were the following: a U-shaped, distended, fluid-filled bowel loop; the whirl sign; the beak sign; a triangular loop; two adjacent collapsed loops of bowel at the site of obstruction; or all of these. CT signs of strangulation, seen in 10 of the 16 patients with ischemic or infarcted bowel, were associated with the appearance of the bowel wall (thickening, high attenuation, and the target sign), abnormalities in the attached mesentery, or both. In mechanical obstruction of the small bowel, detection of ischemic changes in the bowel wall or mesentery with CT indicates strangulation. Absence of CT findings of ischemia or infarction does not rule out strangulation.

Renal cell carcinoma: earlier discovery and increased detection.

To document the earlier discovery and increased detection of renal cell carcinoma, the authors reviewed cases of renal cell carcinoma detected at their institution during 1974-1977 and 1982-1985, with particular emphasis on renal tumors 3.0 cm or smaller. Only 5.3% (four of 75) of renal cell carcinomas found during 1974-1977 but 25.4% (31 of 122) found during 1982-1985 were 3.0 cm or smaller, an increase of almost five times. Of the small tumors in the 1982-1985 group 96.7% (30 of 31) were incidentally discovered, and 77.4% (24 of 31) were initially detected with computed tomography (CT) or ultrasound (US). In the later series 48.4% (15 of 31) of the small renal tumors were treated with partial nephrectomy. Follow-up shows no recurrences. Many more small renal tumors are being detected because of the use of CT and US. This will undoubtedly increase the cure rate of renal cell carcinoma because these tumors are being detected when they are small and do not cause symptoms. Partial nephrectomy will increasingly be used in the management of these small tumors.

CT diagnosis of renal angiomyolipoma: the importance of detecting small amounts of fat.

Six patients were reviewed who had renal angiomyolipoma (1.2-4.0 cm) in which only minimal amounts of fat were evident on CT. The fat content of the lesion was appreciated because tissue attenuation measurements of small areas of low attenuation within the tumors were performed and because thin-section (5-mm) and nonenhanced CT scans were used. The fat content of the lesions could be identified on 10-mm sections in three cases but only on 5-mm sections in three others. In two cases, fat was seen only on the nonenhanced 5-mm thin sections. Careful sampling of low-density regions within the mass must be performed because a single region of interest over the entire tumor will produce an average attenuation in the soft-tissue range. The use of 5-mm thin sections and thin, nonenhanced CT sections increases spatial and density resolution and decreases susceptibility to partial-volume effects. In a correlative study, no areas of fat were detected in a review of 100 well-circumscribed (4.0 cm or smaller) renal cell carcinomas. Detecting the existence of fat in a renal lesion will establish the diagnosis of angiomyolipoma and is the only radiologic finding that can differentiate it from renal cell carcinoma. Thus, unnecessary surgery will be avoided in these cases.

Liver and abdominal screening in patients with cancer: CT versus MR imaging.

A prospective multiinstitutional study was performed to compare the ability of dynamic sequential contrast material-enhanced computed tomography (CT), delayed contrast material-enhanced CT, and two T1-weighted magnetic resonance (MR) sequences (spin echo and inversion recovery) to demonstrate metastatic disease in the liver and abdomen in patients with cancer. All four techniques had comparable rates of hepatic lesion detection when compared individually or when the combined CT techniques were compared with the combined MR techniques. The sensitivity to hepatic disease was 96% (27 of 28 patients) for the combined MR techniques versus 93% (26 of 28 patients) for the combined CT techniques. However, CT was statistically superior in the detection of extrahepatic disease, with significant extrahepatic findings demonstrated by CT in only 12 of 59 patients (20%). For this reason, the authors continue to recommend CT in the initial screening of patients with cancer for upper abdominal metastatic disease.

Computed tomography of midline cysts of the prostate.

Midline cysts in the male pelvis are a confusing entity due to their relatively infrequent presentation and the uncertainty as to their origin and classification. We report on CT appearance of four cases of midline prostatic cysts. Ultrasound correlation was available in one case. Two patients presented with lower urinary tract symptoms (hematospermia and/or hematuria), and two were asymptomatic, with one case detected on physical examination and one found incidentally on CT. Computed tomography demonstrated a characteristic sharply marginated, low density, homogeneous midline cyst within the prostate. On ultrasound a well defined midline anechoic cystic mass was seen. These cases are illustrated and a discussion of cystic masses in the male pelvis is included.

Accuracy of CT in detection of persistent or recurrent ovarian carcinoma: correlation with second-look laparotomy.

Computed tomographic (CT) studies in 39 patients with advanced ovarian carcinoma were retrospectively evaluated to assess their accuracy in detection of persistent or recurrent disease as seen at second-look laparotomy (SLL). Twenty patients were studied before June 1983 (group 1), and 19 patients were studied afterward (group 2). There were 16 true-positive, ten true-negative, two false-positive, and 11 false-negative examinations. Five false-negative studies resulted from microscopic disease found at SLL. In group 1, there were eight false-negative studies. In five, macroscopic disease was not recognized. In group 2, there were three false-negative studies; in one, macroscopic disease was not recognized. Statistical analysis showed an observable improvement in the accuracy in group 2. The differences included use of faster scanners, routine use of thin sections for the pelvis, and air-contrast colonic opacification in group 2. These results suggest that carefully performed scanning on state-of-the-art equipment may have a higher accuracy in documenting persistent or recurrent macroscopic tumor.

Right adrenal pseudotumor caused by colon: CT demonstration.

Multiple adrenal pseudotumors have been previously described on CT and routine radiography. In the following case report we demonstrate interposition of normal colon between the liver, kidney, and adrenal in the hepatorenal recess that produced the CT appearance of a pseudotumor of the right adrenal gland.

Retroperitoneal fibrosis presenting as colonic dysfunction: CT diagnosis.

In a patient who presented with pelvic pain and changed bowel habits, barium enema and sigmoidoscopic examinations demonstrated a nonspecific asymmetric narrowing of the colon at the rectosigmoid junction with normal mucosal appearance. Computed tomography revealed the etiology to be retroperitoneal fibrosis with pelvic extension and entrapment of the colon at this level. The importance of CT in diagnosis of this unusual manifestation of retroperitoneal fibrosis is discussed.

The use of computed tomography in the diagnosis of carcinoma of the renal pelvis causing ureteropelvic junction obstruction.

The computed tomographic (CT) appearance of 5 cases of primary malignancy of the renal pelvis causing ureteropelvic junction (UPJ) obstruction is presented. The tumors appeared as enhancing thickened, nodular, and crescentic masses at the UPJ. Comparison is made to the thin, regular wall of the hydronephrotic pelvis caused by congenital UPJ obstruction. Differentiation from other causes of UPJ obstruction by CT is discussed. A CT scan is particularly valuable when the cause of UPJ obstruction remains elusive after urography and pyelography.

Perforated colorectal neoplasms: correlation of clinical, contrast enema, and CT examinations.

Results of clinical, contrast enema (CE), and computed tomographic (CT) examinations in 39 patients with perforated colorectal neoplasms were retrospectively reviewed. Twenty patients were toxemic at initial presentation, but in only four patients was the diagnosis of perforated colorectal neoplasm initially suspected clinically. CE study was performed in 22 patients and enabled the diagnosis of perforated neoplasm in 11 cases, neoplasm alone in eight, and neither neoplasm nor perforation in three. CT was performed in 38 patients and enabled the diagnosis of perforated neoplasm in 36; pericolic phlegmon but no mass lesion was evident in two. In 16 patients, CT also demonstrated metastatic disease. Because of its reliability in establishing the diagnosis and staging the extent of the inflammatory and neoplastic disease, CT is indicated in cases of suspected or proved perforated colorectal neoplasm and in cases in which CE study findings are indeterminate or suggestive of perforated neoplasm.

Postpartum renal vein thrombosis with left retroaortic renal vein.

An unusual case of thrombosis in a left retroaortic renal vein is presented. Noninvasive radiologic diagnosis is reviewed.

Gastric duplication cyst: GI series and CT correlation.

The radiographic and computed tomographic findings of a communicating gastric duplication first diagnosed in a 55-year-old man are presented and the pertinent literature is reviewed.

"Faceless kidney": CT sign of renal duplicity.

A CT sign of renal duplicity is described. In kidneys with either bifid renal pelvis or complete duplication of the collecting system, a transverse CT section obtained at the mid pole or junction of the fused upper and lower pole cortical moieties may reveal a "faceless" renal appearance lacking vascular or collecting system elements. Recognition of this finding allows a correct diagnosis of partial or complete duplication of the renal collecting system and prevents a false impression of an intrarenal mass lesion.

CT demonstration of rapid improvement of retroperitoneal fibrosis in response to steroid therapy.

A case of retroperitoneal fibrosis with hydronephrosis was treated with cortisone therapy. Computed tomographic images recorded marked and rapid reduction in the size of the soft tissue fibrotic mass and resolution of the hydronephrosis.

Abdominal tuberculosis: CT evaluation.

The computed tomography (CT) scans of 27 patients with abdominal tuberculosis were reviewed retrospectively to determine the range of abdominal involvement. Most patients had been at increased risk because of intravenous drug abuse, alcoholism, acquired immunodeficiency syndrome (AIDS), cirrhosis, or steroid therapy. The etiologic agent was Mycobacterium tuberculosis in 23 patients and M. avium-intracellulare in four patients with AIDS. In five patients, tuberculosis was limited to the abdomen. CT findings included adenopathy, splenomegaly, hepatomegaly, ascites, bowel involvement, pleural effusion, intrasplenic masses, and intrahepatic masses. Characteristic features were a tendency for adenopathy to prominently involve peripancreatic and mesenteric compartments, low-density centers within enlarged nodes, complex nature of the ascites, and adenopathy adjacent to sites of gastrointestinal tract involvement. Recognition of these manifestations and maintenance of an index of suspicion, especially in patients at risk, should help optimize the correct diagnosis and management of intraabdominal tuberculosis.

Ovarian metastases: computed tomographic appearances.

Computed tomographic scans of 34 patients with ovarian metastases were reviewed to assess the radiographic appearances and to correlate these with the primary neoplasms. Primary neoplasms were located in the colon (20 patients), breast (six), stomach (five), small bowel (one), bladder (one), and Wilms tumor of the kidney (one). The radiographic appearance of the metastatic lesions could be described as predominantly cystic (14 lesions), mixed (12 lesions), or solid (seven lesions). There was one false-negative examination which showed no ovarian enlargement, although neoplastic deposits were found on the ovary at laparotomy. The cystic and mixed lesions tended to be larger in overall diameter than the solid. The metastases from gastric carcinoma appeared solid in four of five cases. The metastases from the other neoplasms had variable appearances simulating primary ovarian carcinoma.

Cytomegalovirus esophagitis and gastritis in AIDS.

The radiographic features of cytomegalovirus involvement of the upper gastrointestinal tract in four homosexual men with acquired immunodeficiency syndrome (AIDS) are described. Esophageal involvement (three cases) was demonstrated as a localized ulceration or as a more diffuse esophagitis affecting predominantly the distal esophagus. Gastric involvement (two cases) presented as large nodular rugal folds in the fundus or as a circumferentially narrowed antrum deformed by numerous large nodular contour defects. Endoscopy revealed mucosal erosions, serpiginous ulcers, and inflammatory exudate; biopsies documented the presence of typical inclusion bodies in the epithelial and endothelial cells. Although the radiographic findings are nonspecific, the diagnosis of cytomegalovirus esophagitis and gastritis should be suspected when similar abnormalities are present in immunocompromised patients, particularly homosexual men with AIDS.

CT evaluation of gastrointestinal leiomyomas and leiomyosarcomas.

Computed tomographic (CT) features in 29 patients with gastrointestinal leiomyomas and leiomyosarcomas were analyzed and compared. Features evaluated included size, shape, homogeneity, response to intravenous contrast material, and presence of calcification. The sarcomas were larger (average, 12 cm) than the myomas (average, 4.8 cm), had an irregular shape, and had a nonhomogeneous appearance both before and after contrast enhancement. Gross features depicted on CT are compared with gross pathologic criteria. Analysis of the CT appearance suggested malignancy in two cases in which microscopic examination was interpreted as benign.