The scintigraphic appearance of childhood moyamoya disease on cerebral perfusion imaging.

OBJECTIVE: This study was performed to evaluate the role of single photon emission computed tomography (SPECT) perfusion imaging in the evaluation of patients with moyamoya disease. MATERIALS AND METHODS: Five patients (four female, one male) were studied utilizing iodine-123 iodoamphetamine or technetium-99m hexamethylpropyleneamine oxime SPECT. The data were reconstructed into axial, coronal and sagittal sections for review, and compared with CT, MR and/or angiographic images. RESULTS: All five patients had significant perfusion defects. These areas of vascular compromise were seen to cross normal vascular territories, and were greater in number and extent than seen on anatomic sectional imaging. CONCLUSION: Patients with moyamoya disease have a recognizable pattern of scintigraphic perfusion deficits which should be identified by pediatric imaging physicians. SPECT perfusion studies should be performed in conjunction with other imaging modalities (CT, MR or angiography).

Fluorodeoxyglucose-positron emission tomography in the detection and staging of lung cancer.

Glycolysis is increased in tumor tissues. [18F]fluoro-2-deoxy-D-glucose (FDG) is a glucose analogue radiopharmaceutical used in positron emission tomography (PET) to trace glucose metabolism. We investigated the sensitivity and specificity of FDG-PET imaging in the diagnosis and staging of lung cancer. One hundred and seven patients who had abnormal chest roentgenograms underwent whole-body PET imaging using FDG. PET scan results were classified as positive or negative based on the presence or absence of increased FDG uptake in the lung and/or in the mediastinum. All 82 patients with lung cancer had increased FDG uptake in the lungs, whereas only 12 of 25 patients with nonmalignant diseases had increased FDG uptake. Sixteen lung cancer patients with mediastinal metastases had increased FDG uptake in the mediastinum, of whom three had no lymphadenopathy on computed tomography of the chest. Sixteen lung cancer patients without mediastinal nodal involvement had no FDG uptake in the mediastinum. Seven of these patients had lymphadenopathy on computed tomography. FDG-PET imaging is 100% accurate in predicting mediastinal involvement in patients with lung cancer. It is 100% sensitive and 52% specific in predicting the malignant nature of a chest radiographic abnormality.

Age-associated memory loss: initial neuropsychological and cerebral metabolic findings of a longitudinal study.

To determine the relationships between clinical and brain function in persons with a familial risk for Alzheimer's disease, the authors assessed subjective and objective cognitive abilities, mood state, and cerebral glucose metabolism (using positron emission tomography) in 43 persons with age-associated memory impairment, with and without first-degree relatives with a clinical diagnosis of Alzheimer's disease. Subjective complaints of memory loss, mood state ratings, and objective memory measures were similar in persons with a family history of Alzheimer's disease (n = 29) compared to those without such a history (n = 14). Metabolic ratios in the frontal regions correlated with a decrease in a specific type of subjective memory complaint (mnemonics usage; p < .001) and some mood state ratings. These results indicate that parietal and temporal hypometabolism is not evident in persons with mild age-related memory complaints, even when such subjects have a familial risk for Alzheimer's disease. Moreover, self-reports of mnemonics usage may be sensitive indicators of decreased frontal lobe function. Longitudinal study will determine whether such clinical and metabolic measures will predict eventual disease progression.

Leksell stereotactic radiosurgery in the treatment of eye melanoma.

Current experiments indicate that a focussed single radiation treatment with a dose of 6000 to 9000 rads delivered to the 90% zone through a collimator of the Leksell stereotactic radiosurgical unit or 'gamma knife' to the rabbit eye melanoma model is capable of destroying the cancer totally and thus effecting a cure. The beneficial effect in these rabbit eye melanoma experiments appears to be similar to the results obtained by physicians using the Harvard and Berkeley cyclotrons in treating malignant neoplasms in the human eye. Therefore, it is proposed that a properly designed stereotactic radiosurgical unit can be used in patients with eye tumours similar to those selected for the cyclotron systems.