Emission and transmission brain tomography.

Comparative emission and transmission brain tomograms were obtained in 209 patients to establish the diagnostic accuracy of a new emission tomographic scanner in detecting space-occupying disease in the brain. Concordant results were obtained in 169 patients (81%). Computed transmission tomography (transmission CT) yielded an overall rate of false-positive results of 0.48% and a false-negative rate of 6%. Emission CT yielded a false-positive rate of 0% and false-negative rates of 2.4% for malignant disease and 10% for vascular disease. The higher rate of false-negative results for vascular disease with emission CT occurs because transmission CT can detect old infarction. The rates of detection of recent vascular disease with emission and trnasmission CT are identical. Thus emission CT is highly sensitive in detecting space-occupying disease in the brain. It represents an ideal screening procedure.