Jerry M. Brown

Scintigraphic findings in a primary cerebral amyloidoma.

Bone, brain, and gallium scintigrams are presented of a 48-year-old man with biopsy-proven cerebral amyloidosis. Brain scintigraphy revealed a wellcircumscribed 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.

Angiographic and scintigraphic findings in fibrosing mediastinitis.

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.

Ga-67 positivity in sarcoidosis of the skin with coincident thyroid uptake of uncertain etiology.

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.

Discovery of a renal medullary carcinoma in an adolescent male with sickle cell trait by Tc-99m methylene disphosponate bone scintigraphy.

The renal excretion of Tc-99m bone imaging agents often permits the identification of urinary tract abnormalities on bone scans. In this case report, identification of focal intrarenal stasis of the excreted bone imaging agent led to additional anatomic imaging and the identification of a renal medullary carcinoma (RMC) in an adolescent black male undergoing evaluation for back pain. RMC is a rare, highly aggressive renal neoplasm found almost exclusively in young individuals with sickle cell trait (SCT) or hemoglobin SC disease. The prognosis of RMC is poor because the malignancy is usually refractory to chemotherapy and radiotherapy, with metastatic disease commonly present at the time of diagnosis.

Unexpected reversal of gallium-67 citrate avidity in an anaerobic hepatic abscess

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.

The complementary roles of brain scintigraphy and computed tomography in multiple sclerosis.

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.

F-18 FDG PET/CT imaging of cortical bone metastases.

Osteolytic cortical bone metastases (CBM) saucerize cortical bone surfaces and, especially in tubular bones, may demonstrate a unique appearance differentiating them from the much more commonly observed metastatic disease in the medullary space of bone. A Tc-99m methylene diphosphonate 3 phase bone scan in our 58-year-old male patient who presented with a 3-month history of worsening bilateral lower extremity pain was positive in all 3 phases at the mid-diaphyseal levels of both tibiae. Correlative plain film radiographs demonstrated extensive geographic cortical osteolysis in both tibiae consistent with CBM. Extramedullary hypermetabolic masses associated with cortical osteolysis were demonstrated at these tibial sites by F-18 FDG PET/CT scanning. A presumed primary lung poorly differentiated neoplasm with extensive dissemination in and beyond the chest to other osseous structures, cervical lymph nodes, both adrenal glands, and brain was the most likely source of his CBM.

Delayed Imaging of Meckelʼs Diverticulum: Observation of a Quadrantal Shift

A 10-year-old male with no significant medical history presented to the emergency room with 2 episodes of painless bright red rectal bleeding within the previous 24 hours. A Meckel’s scan utilizing 5.12 mCi of Tc-99m pertechnetate injected intravenously was performed. Continuous anterior images of the abdomen were obtained for 60 minutes. Postvoid images at 1 and 3 hours were also obtained. Coincident with the appearance and progressive intensity of gastric mucosal uptake, a focal accumulation of Tc-99m pertechnetate was observed in the right lower quadrant, just superior to, and separate from the urinary bladder. This finding was consistent with a Meckel diverticulum (MD). Notably, the 3-hour delayed image demonstrated a shift in position of this focus to the left lower quadrant, again just superior to the urinary bladder. A MD was confirmed surgically. As this case illustrates, a scan-positive MD may change in position during imaging and can be differentiated from active gastrointestinal bleeding by the absence of characteristic radiotracer transit through the gut.

Profound xenon-133 trapping in left main bronchus. Obstruction by necrotic tumor.

Squamous cell carcinoma of the esophagus eroded into the central airway with production of left main bronchus occlusion and aspiration pneumonia of the right lower lobe.