Comparison of computed tomography with high-resolution real-time ultrasound in the localization of the impalpable undescended testis

Localization of an undescended testis was attempted in 23 instances in 20 patients using both computed tomography (CT) and high-resolution real-time ultrasonography. The testis was identified and correctly localized 16 times by CT and 15 times by ultrasound. There was one false-negative diagnosis by CT and two by ultrasound. False-positive diagnoses were not made with either modality in the six cases in which the testis was not found during exploratory surgery. CT showed 94% sensitivity, 100% specificity, and 96% accuracy; ultrasound resulted in 88% sensitivity, 100% specificity, and 91% accuracy. The authors recommend high-resolution real-time ultrasound as the modality of choice for this procedure because it is simple, accurate, and avoids the use of ionizing radiation. CT may be used when ultrasound findings are negative or equivocal. Angiography should rarely be required.

Utility of CT-guided abdominal aspiration procedures

Over 200 consecutive diagnostic needle aspiration procedures of the abdomen were performed under computed tomographic (CT) guidance. Biopsies were done of the liver in 88 patients, the pancreas in 28, the kidney in 20, and the retroperitoneum in 32; 30 underwent an aspiration procedure for characterization of an intraabdominal fluid collection. Accuracy of diagnosis was very high for hepatic (99%) and renal (100%) biopsies and in characterization of fluid collections (100%). Accuracy for retroperitoneal biopsy was 87.5% and for pancreatic biopsy 82%. Overall accuracy for all sites was 95%. There were one false-negative diagnosis for the liver and five false-negative diagnoses for the pancreas. Insufficient material was obtained for diagnosis in four instances of retroperitoneal biopsy. There were no false positives. The technique is facilitated by rapid CT scan time, large aperture gantry, and rapid CT image reconstruction. Twenty gauge needles were used more frequently than 22 gauge needles because of their greater rigidity and ease of control. CT-guided diagnostic aspiration procedures are particularly useful for diagnosis of small, deep-seated lesions and in evaluation of lesions found in severely ill patients. An experienced cytologist is essential to the success of the technique.

The role of computed tomography in pelvic fractures

Adequate radiologic demonstration of the extent of pelvic fractures facilitates planning of their treatment by the orthopedic surgeon. Traditionally, this evaluation has been by conventional radiology. This report details results of computed tomography (CT) in the evaluation of pelvic fractures in 34 patients. In most cases, CT was able to identify and delineate the extent of fractures, demonstrate displacement of the involved bones, localize bone fragments and characterize joint derangements. Many of these features were better demonstrated at CT compared with conventional radiographs. In particular, in 10 patients loose bodies were seen at CT that were not evident on conventional radiography. The extent of associated soft tissue injury is also well shown by CT and demonstrated peripelvic or intraarticular fluid collections can be aspirated under CT guidance to rule out sepsis. This study suggests that CT is useful in the assessment of major pelvic fractures.

Normal thymus: CT characteristics in subjects under age 20

The chest computed tomographic (CT) scans of 40 subjects aged 20 or younger were analyzed retrospectively with special attention to the anterior mediastinum and the thymus. Thirty-four of the patients were considered to have normal CT appearances of the anterior mediastinum; neoplasm was suspected at this site in the other six. In the normal group, the gland was consistently identified as a characteristic anterior mediastinal structure. It had smooth, undulating, lateral contours tending to be convex laterally in the very young and concave laterally at an older age, although there was overlap in many in whom the shape of the lateral contours was a combination of convex, concave, or straight. A sharp angular contour to the lateral margin of the thymus was seen occasionally and is also thought to be characteristic of normal thymus. The posterior border of the gland molded to the heart and great vessels in all patients. The anterior contour was molded to the anterior chest wall or had a pointed shape directed toward the sternum. Molding to the mediastinum and chest wall was not found or was present to only a limited degree in the patients with anterior mediastinal tumor. Attenuation values varied between different normal glands and within the same gland on both pre- and postcontrast scans. Recognition of normal variation in the CT appearance of the thymus in young patients may prevent false-positive diagnosis of neoplasm.

Diagnosis of parathyroid adenoma by computed tomography

A diagnosis of cervical parathyroid adenoma was made at computed tomography (CT) in two patients not initially suspected of having primary hyperparathyroidism. In each case, the lesion appeared as an oval shaped mass indenting and deforming the posterior surface of one lobe of the thyroid gland. In one patient, the lesion was sharply contrasted by iodine-containing thyroid tissue, which appeared denser than the adenoma. The significance of these findings is discussed as well as some of the problems encountered in the CT diagnosis of parathyroid adenoma.

The direct visualization of blood flow by real-time ultrasound: clinical observations and underlying mechanisms

The observation of spontaneous low-amplitude echoes from the blood in the larger blood vessels has not been satisfactorily explained. In vitro experiments were performed to study flowing and stationary blood by ultrasound. In both cases numerous low-level echoes were seen in blood and suspensions of washed red cells. No echoes were observed in plasma or solutions of hemoglobin. It was concluded that the red blood cells is the most likely scattering agent responsible for the contrast effect observed clinically.

CT diagnosis of venous pseudotumors in the chest and abdomen

Appearances simulating neoplastic masses were found in five patients undergoing computed tomographic (CT) scanning of the chest and abdomen for a variety of indications. In each case the appearance was shown to be due to dilated collateral venous channels in association with portal hypertension or interruption of the inferior vena cava. The vascular origin of the masses was confirmed by CT scanning during intravenous bolus injection of contrast. Angiographic confirmation was obtained in three subjects. Enlarged collateral veins should be considered in the differential diagnosis of appearances suggesting mediastinal or abdominal lymphadenopathy at CT scanning.

Superior gluteal artery haemorrhage following pelvic features controlled by embolisation

Successful embolisation of active bleeding from the superior gluteal artery seen in two patients within the last 12 months is described. Both patients had extensive abdominal and pelvic injuries. One patient eventually died from renal failure and a perforated colon. The other patient is mobile and has been periodically seen in the out-patient department over the past nine months. In both instances, haemorrhage was at the sacrosciatic notch. Early angiography, in patients with extensive pelvic trauma and major blood requirements, with intent to embolise any identifiable bleeding source would appear to be the best initial manoeuvre to prevent exsanguination.

Spina bifida and unilateral focal destruction of the distal femoral epiphysis

Focal destruction of the postero-lateral distal femoral epiphysis was present on radiographs in two children with spina bifida and objective lower limb sensory loss. Each patient presented with painless swelling of the knee. In one patient the epiphysis showed sclerosis and fragmentation associated with a defect. In the second patient the destructive change was the dominant radiographic abnormality and simulated bone tumor. Computed tomography in this patient showed a bone fragment occupying the defect suggesting epiphyseal fracture. The lesion in each patient was believed to be traumatic in origin and to represent a stage in the development toward neuropathic arthropathy.

Erosive azotemic osteodystrophy

Serial macroradiographs of the hands of 80 patients on maintenance hemodialysis were reviewed to assess the frequency and distribution of articular and periarticular erosions. Articular and periarticular erosions are common and were demonstrated in 24 (30%) of 80 patients. The pattern and distribution of the erosions are unlikely to be confused with any of the well known erosive arthropathies except in an unusual circumstance. The presence and severity of the erosions do not correlate with the severity of subperiosteal resorption of the middle phalanges and in several instances were accompanied only with resorption of the phalangeal tufts. The erosions may progress with time, but do not seem to have any bearing on clinical symptoms. In no instance did the erosions disappear after removal of parathyroid adenomas. Recognition of the frequency of these erosions broadens the spectrum of skeletal changes found in azotemic osteodystrophy, but does not in any way warrant further investigation since they are clinically innocuous.

Computed tomography in the diagnosis of gluteal abscess and other peripelvic fluid collections

During an 18 month period, five patients of all those being investigated by computed tomography (CT) for suspected abscess were found to have localized peripelvic extraabdominal fluid collections. In three, this was due to primary abscess or pyarthrosis and to probable secondary infection of a degenerated hematoma or seroma in two. The lesions were responsible for or considered contributory to the patient's febrile illness in each case. The collections were inconspicuous or poorly localized clinically but readily apparent on CT. Treatment by CT guided needle aspiration or operative drainage was performed in each patient and was followed by relief of symptoms and fever.

CT findings in thoracic aortic dissection

Computed tomography (CT) findings in 11 cases of aortic dissection were correlated with aortographic, surgical, or postmortem findings. In another two patients, the CT findings were considered diagnostic of aortic dissection but no further workup was performed. All the CT examinations were made before and after bolus injection of contrast. Many of the familiar angiographic signs were appreciated on CT, such as a thickened aortic wall, septum between two opacifying lumens, differential time density between the two lumens, and compression of the true lumen. No false-positive or false-negative studies were encountered. This experience suggests that CT is a reliable, noninvasive method for the diagnosis of aortic dissection.

Demonstration of unsuspected malignant disease of the pericardium by computed tomography

Massive pericardial effusion associated with mediastinal neoplasm was first diagnosed by findings at computed tomography (CT) in two patients. In each case the CT findings prompted urgent pericardiocentesis for relief of pericardial tamponade. One of the patients was subsequently found to have a widely disseminated renal papillary adenocarcinoma, and the other had fibrosarcomatous mesothelioma of the pericardium. The role of CT in the diagnosis of pericardial disease is discussed.