Michael R. Paling

Respiration artifacts in MR imaging: reduction by breath holding

Respiratory motion commonly produces degradation of image quality on magnetic resonance scans of the upper abdomen due to artifacts produced in the direction of the phase encoding gradient. Such artifacts may be reduced, although not eliminated, on image sequences obtained with relatively short acquisition times by means of breath holding during the middle 20% of the sequence.

Tumor invasion of the anterior skull base: a comparison of MR and CT studies.

Seven patients who had tumors arising in the anterior face or paranasal sinuses and invasion of the anterior skull base were evaluated with magnetic resonance (MR) and high resolution CT. Magnetic resonance was superior in evaluating tumor encasement of the carotid artery and invasion of the cavernous sinus; for assessing the relationship of the tumor to the anterior brain, optic nerves, and optic chiasm; in providing coronal images free from dental artifact; and in determining tumor extent within the infratemporal fossa. Bone destruction was more easily observed on CT than MR.

Computed tomography in malignant fibrous histiocytoma.

The computed tomographic findings in 11 cases of malignant fibrous histiocytoma are discussed. The typical appearance of the eight primary tumors imaged was of a poorly marginated mass with an attenuation coefficient slightly lower than that of normal muscle. Central tumor necrosis was detected in three cases. Three of five abdominal tumors showed involvement of adjacent soft tissue structures, and one demonstrated destruction of adjacent bone. The nonspecific appearance of these tumors prevented their reliable differentiation from other soft tissue sarcomata.

Plexiform neurofibroma of the pelvis in neurofibromatosis: CT findings

Three cases of intrapelvic plexiform neurofibromas are presented in patients with neurofibromatosis. In all three cases computed tomography demonstrated widespread sheets of nodular tissue lying in an extraperitoneal location in front of the sacrum or extending along the pelvic sidewalls . Symptomatology in these patients related to compression of either nerve roots or adjacent vessels. It is important to differentiate these lesions from pelvic lymphadenopathy to prevent a mistaken diagnosis of malignant disease.

Spinal lipoma presenting as a mediastinal mass: diagnosis by CT.

Spinal lipomas account for less than 1% of all spinal tumors. Prior to the advent of computed tomography, the preoperative diagnosis could only be suggested on the basis of nonspecific clinical and radiographic findings. We report a case of an unusual spinal lipoma that presented as a mediastinal mass. The low attenuation values of the tumor allowed a preoperative diagnosis. Computed tomography with metrizamide should serve as the first diagnostic procedure for evaluation of spinal lipomas.

Gastric manifestations of North American Burkitt's lymphoma

Stomach involvement is rare in American Burkitts lymphoma. Three cases were noted in 66 patients, and all were associated with large left upper quadrant masses. The appearance of Burkitts lymphoma of the stomach is similar to other lymphomas and consists of diffuse infiltration of the wall, mucosal thickening, ulcerations, and intra- and extragastric masses. Extension into the oesophagus was noted twice, and small bowel masses were associated with two cases. CT scanning and ultrasound are useful for defining extragastric extent of tumour. Rapid reversion to a more normal appearance is noted following chemotherapy.

Lower lobe collapse due to pleural effusion: a CT analysis.

In the presence of a pleural effusion, volume loss is seen in the adjacent lung, primarily in the lower lobe. With a modest effusion a compliant lower lobe may show displacement and generalized volume loss without focal atelectasis, but more commonly segmental atelectasis does occur, typically in the posterior basal segment. Large effusions result in a major degree of lower lobe collapse. The collapsed lobe tends to be uplifted by the fluid and compressed toward the hilum with consequent stretching and attenuation of the inferior pulmonary ligament, rather than collapsing posteriorly and medially.

The First Rib as the Cause of a “Pulmonary Nodule” on Chest Computed Tomography

A protuberance arising from the first rib may simulate a pulmonary nodule on computed tomography of the chest. The typical location of this density should suggest its true nature, which may be confirmed by a frontal chest radiograph.

The computed tomography of normal long bone anatomy and its simulation of disease

Abstract Normal bony anatomy as depicted by computed tomography (CT) may, in the region of the knee, hip and shoulder, incorrectly suggest the presence of pathology. Cortical destruction and new bone formation may be simulated at these sites. The normality of the medullary cavity and of the soft tissues are important in differentiation from genuine pathological lesions, with which comparisons are made.

The roving aorta of Marfan's syndrome: A case report

Real-time ultrasound demonstrated an unusual degree of side-to-side mobility of the abdominal aorta in a patient with Marfans syndrome. With only moderate pressure, it was possible to displace the aorta to the right side of the spine. It is postulated that this phenomenon results from abnormal laxity of retroperitoneal connective tissue.