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Cerebral computed tomography, with and without iodinated contrast, revealed the appearance and evolution of lesions in a 32-year-old man with multiple sclerosis. Two areas were enhanced with contrast, with one showing a mild mass effect and rim of enhancement. Serial brain scintigraphy using technetium-99m glucoheptonate, following the computed tomography, showed the appearance and regression of corresponding regions of increased uptake. Computed tomography one day prior to brain scintigraphy failed to demonstrate a region of increased accumulation of radiotracer. One week later, however, evidence of a corresponding unenhanced defect was noted on computed tomography. Clinical correlation is given additionally.

The clinical and morphologic findings in the case of a 47-year-old man with fibrosing mediastinitis, most probably due to histoplasmosis, are described. Radionuclide angiography demonstrated obstruction of the superior vena cava with collateral vascularization. Computed tomography demonstrated a large calcific mass interposed between the pulmonary artery and superior vena cava suggesting potential pulmonary vasculature involvement. For this reason, pulmonary scintigraphy was performed which showed right lung perfusion and ventilation defects. Radionuclide angiography and pulmonary scintigraphy complement each other in determining the extent of vascular involvement with fibrosing mediastinitis. However, contrast venography is necessary to correctly delineate the anatomy of the obstructed superior vena cava and its collaterals.

Bone, brain, and gallium scintigrams are presented of a 48-year-old man with biopsy-proven cerebral amyloidosis. Brain scintigraphy revealed a well-circumscribed accumulation of Tc-99m pertechnetate in the amyloidoma. Bone scintigraphy using Tc-99m methylenediphosphonate likewise exhibited increased activity in the same area. Gallium-67 citrate, however, failed to localize within the amyloidoma.

A case of anaerobic hepatic abscess (Bacteroides fragilis), which initially was imaged as a cold defect on Ga-67 citrate scintigraphy and, following percutaneous drainage, became Ga avid, is presented. Proposed mechanisms for this occurrence are given.

A 16 year-old boy presented with a firm mass within the left thigh. Ga-6 7 citrate and bone scintigraphy revealed soft tissue radiotracer accumulation within the mass lesion. Radiographs and xerography of the left thigh revealed calcification within the soft tissue mass typical of myositis ossificans. The patient's clinical course was uneventful.

Gallium-67 citrate scintigraphy of a 26-year-old woman with systemic sarcoidosis demonstrated abnormal radiotracer uptake within multiple biopsy-proven sarcoidal cutaneous lesions and within both lobes of the thyroid gland. The etiology of the thyroidal uptake of the Ga-67 was uncertain but it may represent sarcoidal involvement of the gland.

A 47-year-old man presented with the clinical findings of acute cholecystitis. During hepatobiliary scintigraphy using Tc-99m DISIDA, a persistent photopenic defect was noted within the inferior portion of the liver in the region of the gallbladder. Abdominal ultrasonography revealed large gallstones with acoustic shadowing within a normal-sized gallbladder. Eleven large gallstones were found within a normal-sized intrahepatic gallbladder at surgery.