Computed tomography of the pancreas: three second scanning versus 18 second scanning

Diagnostic accuracy of pancreatic computed tomography (CT) using a 3 s scanner was compared to our previously published results using an 18 s scanner. Technically unsuccessful examinations have decreased to less than 1%. Pancreatic masses were detected prospectively in 83% of patients with pancreatic carcinoma and retrospectively in all such patients. False negative diagnoses of normal pancreas in proven pancreatic carcinoma were reduced fourfold down to 6%. False positive diagnoses of pancreatic carcinoma remained less than 1% but were not significantly reduced compared to our second year's experience using an 18 s scanner. Interpretation errors and errors due to limitations of CT as a diagnostic technique are discussed.

Sonographic detection of occult testicular neoplasms

Testicular sonograms were performed in four patients with pathologically proven metastatic neoplasms but a normal physical examination of the scrotum. An abnormal echo texture was seen in all cases: focal hypoechoic nodule (about 1 cm) in two, diffusely hypoechoic in one, and mixed diffuse/focal abnormality in one. Correct sonographic identification of the abnormal testis facilitates surgical removal and precludes unnecessary excision of the contralateral normal testes. The authors recommended testicular sonography to be used as a routine procedure in all patients with such a clinical presentation.

Computed tomography of the normal thymus

Recognition of variations in size, shape, and density of the normal thymus on computed tomographic (CT) scans is of paramount importance, lest it be misinterpreted as an abnormal mediastinal mass. Studying patients subsequently proved free of active chest disease, we analyzed 154 CT scans of the mediastinum, performed on a fourth-generation scanner, to determine the incidence of visualization and appearance of the normal thymus. The thymus was seen in 100% of patients under age 30, 73% of patients between 30 and 49 years, and in 17% of patients over 49 years of age. The thickness of the thymus showed a definite decrease in size with increasing age; although the width showed a similar general tendency, a wide variation was noted within each age group. In younger patients, the density of the thymus was similar to that of muscle; the attenuation values progressively decreased in older patients, finally approaching that of fat.

Computed tomography of the abnormal thymus

Computed tomography (CT) should be the imaging method of choice following plain chest radiographs when a suspected thymic abnormality requires further evaluation. Based upon a six-year experience, including the evaluation of 25 patients with thymic pathology, CT was found useful in suggesting or excluding a diagnosis of thymoma and in distinguishing thymic hyperplasia from thymoma in patients with myasthenia gravis. The thickness of the thymic lobes determined by CT was found to be a more accurate indicator of infiltrative disease (thymic hyperplasia and lymphoma) than the width. CT was helpful in differentiating benign thymic cysts from solid tumors, and in defining the extent of a thymic neoplasm. On occasion, CT may suggest the specific histologic nature of a thymic lesion.

Evaluation of three effervescent agents for double-contrast upper gastrointestinal radiography

The agent used to introduce gas into the stomach is an important factor in determining the quality of double-contrast upper gastrointestinal radiography. The efficacy of 3 effervescent agents formulated for use in double-contract upper gastrointestinal radiography was evaluated in 300 patients. Patients found 2 granular preparations (E-Z-Gas granules and Baros) easier to swallow than a powdered agent (E-Z-Gas powder). Bubble formation and flocculation of barium in the stomach were less of a problem with Baros. Differences in mucosal coating and visualization of area gastricae were not statistically significant.

Mesenteric desmoid tumors: sonographic and computed-tomographic appearance

Sonographic and computed-tomographic (CT) findings in two patients with mesenteric desmoid tumors are reviewed. On ultrasound scans, mesenteric desmoids appear as well-circumscribed masses with scattered dense high-level echoes which correspond to mesenteric fat and vessels on the CT scan. Although these tumors appear well marginated on both ultrasound and CT scans, the pathologic examination shows microscopic invasion at the tumor margin in most cases. Differentiation from other mesenteric masses is discussed.

Can real-time ultrasonography replace static B-scanning in the diagnosis of renal obstruction?

Two hundred consecutive patients were evaluated for renal obstruction using both static B-scanning and high resolution real-time scanning. The overall diagnostic accuracy was 93% for the static B-scanner and 94% for the real-time unit, with a false positive diagnostic rate of 8% for each. Because of its greater flexibility and shorter scanning time, real-time can replace static B-scanning in the diagnosis of renal obstruction. It has also become the preferred method of guidance for interventional uroradiological procedures. The pitfalls of real-time scanning in evaluating renal obstruction are also discussed.

Use of CT in evaluation of postcystectomy patients

Twenty-one patients with prior cystectomy for transitional cell carcinoma of the bladder were evaluated by computed tomography. In eight patients who developed local pelvic recurrence, CT diagnosis was correct in seven. CT also detected distant metastasis in five patients and local pelvic abscesses in two additional patients. Our data show CT to be a more sensitive means than conventional radiologic methods including gray scale sonography in the detection of local recurrence and postoperative complications. Examples of normal postcystectomy changes in the pelvis as well as recurrent disease and surgical complications are illustrated. The pitfalls and the proper role of CT in these patients are also discussed.

Hepatitis B viral markers in patients with primary hepatocellular carcinoma in Taiwan

The presence of hepatitis B viral markers in patients with primary hepatocellular carcinoma (PHC) was studied retrospectively at the Taiwan Veterans General Hospital in Taipei, Taiwan. Serum samples from 102 PHC patients and from 100 control individuals were tested for hepatitis B surface antigen (HBsAg), antibody to HBsAg (anti-HBs), antibody to hepatitis B core antigen (anti-HBc), hepatitis Be antigen (HBeAg), and antibody to HBeAg (anti-HBe). Of the 102 PHC patients, 72 (71%) were positive for HBsAg. Nine (9%) additional patients were positive for anti-HBc alone in high titer, 19 (19%) had both anti-HBc and anti-HBs, and 9 (9%) had HBsAg, anti-HBc, and anti-HBs. In the 100 controls, 12 (12%) were HBsAg-positive, whereas 22 (22%) had anti-HBc alone and 50 (50%) had both anti-HBc and anti-HBs. Only 4 (4%) controls and no PHC patients had anti-HBs alone. Of the HBsAg-positive patients with PHC, 17 (29%) had HBeAg and 36 (61%) had anti-HBe. The alpha-fetoprotein (AFP) levels above 400 ng/ml were found in 44% of the PHC patients. Values of AFP above 1 x 10(5) ng/ml were more frequently detected in PHC patients who were HBsAg-positive. Categorization of the geographic origins of the families whose members had PHC revealed that most families had originated from southern China. This study confirms that hepatitis B viral markers are frequently present in Chinese patients with PHC.

The utility of computed tomography in evaluation of extracranial diseases

The application of CT to the extracranial portions of the body has only been possible since 1975, when technological advances made scanning in less than 20 seconds available to radiologists. Our experience during the first 5 years with body CT have been rewarding and we have demonstrated several significant contributions in the radiologic diagnosis of disease entities that have changed the ideal approach to the evaluation of many patients. The introduction and development of body CT has also been controversial on several issues, primarily related to cost. Increasing clinical experience will improve our definition of the strengths and limitations of CT and allow a more precise definition of the efficient utilization of this new technology. Improvements continue to be reported and it is safe to predict that CT will have further applications to clinical diagnosis in the near future.

Acute focal bacterial nephritis: emphasis on gray scale sonography and computed tomography

The radiologic findings of acute focal bacterial nephritis in 13 patients are described. These include (1) focal swelling or mass on excretory urogram; (2) solid mass, often with echo amplitude lower than adjacent normal renal cortex on sonography; and (3) a poorly marginated, low density mass that exhibits patchy and inhomogeneous enhancement after intravenous contrast medium on computed tomographic scans. Serial sonograms are used to monitor the response of these patients to antibiotic therapy. The respective roles of sonography and computed tomography in the diagnosis and management of these patients are discussed.

Utility of computed tomography in the localization of the undescended testis

Computed tomography (CT) was accurate in localizing the undescended testis in eight cryptorchid patients. In three patients the testis was in the lower abdomen, and in five it was in the inguinal canal. In one patient delineation of an unusually large intra-abdominal testis alerted the surgeon to its possible malignant transformation. The advantages and potential pitfalls of CT in preoperative localization are discussed.

Cholecystosonography: accuracy, pitfalls and unusual findings

Gray scale cholecystosonograms in 200 patients were reviewed. The findings in 133 of the patients were proved correct at surgery or autopsy. The overall accuracy for the detection of gallstones was 92 percent, with a false-negative rate of 4 percent. A false-positive diagnosis of cholelithiasis was made in three patients, two of whom proved to have extensive cholesterolosis. Causes of false-negative studies were the presence of a single small calculus, obseity and a large distended gallbladder. Ultrasound was specific but insensitive in the detection of a thickened gallbladder wall. The significance of a nonvisualized gallbladder by ultrasound and the role of ultrasound in the diagnosis of gallbladder disease are discussed.

Limitations of the post-lymphangiogram plain abdominal radiograph as an indicator of recurrent lymphoma: comparison to computed tomography

A comparison was made between post-lymphangiogram abdominal radiographs and computed tomographic (CT) scans in 18 lymphoma patients. When radiographs were obtained more than one year after the original lymphangiogram, only a small percentage of the patients had adequate contrast medium remaining in the lymph nodes for a definitive diagnosis. In three cases with apparently adequate residual contrast material, the radiograph did not provide accurate information on the presence or extent of recurrent lymphoma. The authors conclude that CT is the preferred method for the initial staging of patients with lymphoma, as well as for follow-up studies after one year.

The "overturned lateral" view in arthrography of the knee

A simple method of improving visualization of the posterior horn of the medial meniscus during fluoroscopic spot-filming in arthrography of the knee is described. Since it results in increased diagnostic accuracy at the most common site of occult pathology, the authors recommend that it be part of the routine examination.

Focal irregularity of the rectal mucosa

Mucosal irregularity seen on air-contrast barium enema may be the only radiographic manifestation of a variety of pathologic conditions of the rectum. Seven patients are described to illustrate the fact that when the rectal mucosal irregularity is focal and well demarcated, neoplastic conditions should head the list of diagnostic possibilities. Adenocarcinoma, verrucose carcinoma, adenomatous hyperplasia, villous adenoma, and metastatic carcinoma can all be manifested in this way. The appearance of these lesions on air-contrast barium enema is contrasted with the diffuse mucosal irregularity characteristic of inflammatory and other rectal conditions.