Postradiation cerebellar necrosis mimicking tumor: MR appearance.

Cerebellar necrosis associated with therapy of primary gliomas is unusual. We present the MR findings in a patient with postradiation multifocal cerebellar necrosis mimicking tumor dissemination.

CT patterns of intracranial hemorrhage complicating thrombolytic therapy for acute myocardial infarction.

Computed tomographic (CT) patterns of intracranial hemorrhage (ICH) were determined in 1,696 patients undergoing thrombolytic therapy for acute myocardial infarction. ICH occurred at 33 sites in 0.77% of patients (n = 13). Thirty-six percent of hemorrhages (n = 12) were intraparenchymal, 33% (n = 11) were subdural, 24% (n = 8) were subarachnoid, and 6% (n = 2) were intraventricular. Eight-four percent (n = 26) of all nonventricular hemorrhages were supratentorial in location. The most common site of ICH was supratentorial and intraparenchymal (10 of 33). In 11 of the 13 patients with ICH, clinical symptoms occurred within 24 hours of the initiation of thrombolytic therapy. A fatal outcome resulted in three of the four patients who had clinical symptoms within 3.5 hours after beginning thrombolytic therapy. The CT findings of multiple intracranial bleeding sites, substantial mass effect with midline shift, and large-volume intraparenchymal hematomas were associated with increased mortality. ICH associated with thrombolytic therapy for acute myocardial infarction has a grave prognosis, with 62% of patients dying during hospitalization.

Intracerebral extension of nasal dermoid cyst: CT appearance.

We report on a 46-year-old man with a congenital nasal dermoid cyst that extended intracranially to form large bifrontal intraaxial dermoid cysts, which became secondarily infected through a nasal dermal sinus tract. Computed tomography demonstrated bilateral frontal lobe ring enhancing cystic masses containing fat-fluid levels consistent with dermoid cyst abscesses. Axial and coronal CT of the skull base and nose demonstrated a midline bony canal extending from two dimples on the dorsum of the patient's nose to the base of the anterior cranial fossa. The clinical, CT, and surgical findings are reviewed as well as the embryogenesis of congenital nasal dermoid cysts.

Carotid body tumor: flow sensitive pulse sequences and MR angiography.

The magnetic resonance (MR) appearance of carotid body tumors has been previously described. Classically, these lesions are well circumscribed and highly vascular and cause a characteristic separation of the external and internal carotid arteries. Hypointense foci within these tumors are seen on T1-weighted images. The T2-weighted images snow a "salt and pepper" pattern. We report a carotid bifurcation glomus tumor that exhibited the above features on conventional MR. Multiplanar gadolinium enhanced MR as well as flow-sensitive MR techniques including small flip angle gradient refocused images and MR angiography were performed. Magnetic resonance angiography demonstrated the abnormal morphology of the carotid bifurcation. Axial gradient refocused images revealed evidence of flow within the lesion. The findings were then correlated with postcontrast CT, arterial digital subtraction angiography, and histopathology.

Arteriographic study of variant arterial anatomy of the upper extremities.

Anatomic variations in the major arteries of the upper extremities have been reported in 11-24.4% of individuals. In a review of 100 upper extremity arteriograms, we found an overall incidence of 9%. High origin of the radial artery from the brachial artery was the most frequently encountered anomaly occurring in 7% of individuals and accounting for 78% of all anatomic variations. Origin of the radial and ulnar arteries from the axillary artery was an infrequent finding occurring in only 2% of extremities.

Duplex Doppler ultrasound evaluation of calcified inferior vena cava thrombosis.

We describe the use of duplex Doppler ultrasound in the noninvasive assessment of inferior vena cava patency and abdominal venous flow dynamics in a four month old infant with calcified inferior vena cava thrombosis.

Pulmonary hypertension secondary to serum hyperviscosity in a patient with rheumatoid arthritis.

A patient with rheumatoid arthritis who was evaluated for dyspnea of six months' duration is described. Although no primary cardiac or parenchymal lung disease was identified, right heart catheterization revealed marked pulmonary hypertension. The patient was presumed to have pulmonary arteritis. Evaluation of her hyperproteinemia, however, led to the discovery of a polyclonal gammopathy with a marked increase in plasma viscosity. Although the classic clinical findings of the hyperviscosity syndrome were minimal, the patient underwent plasmapheresis, resulting in a marked reduction of pulmonary artery pressures (from 53 +/- 4 mm Hg, mean +/- SD, to 30 +/- 3 mm Hg, p less than 0.05) and pulmonary vascular resistance (from 707 +/- 63 dynes/second/cm5 to 421 +/- 72 dynes/second/cm5, p less than 0.05) concomitant with a return to normal plasma viscosity. Her dyspnea completely resolved. This represents the first successful treatment of pulmonary hypertension by plasmapheresis. Protein evaluation revealed the presence of intermediate complexes of IgG rheumatoid factor. The hyperviscosity syndrome should be considered in the differential diagnosis of pulmonary hypertension in patients with rheumatoid arthritis and other disorders associated with a polyclonal or monoclonal gammopathy. Pulmonary hypertension secondary to the hyperviscosity syndrome is reversible by plasmapheresis. Immunosuppressive therapy that reduces immunoglobulin production may provide a means of long-term treatment.