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Experience with radionuclide angiography (RA) utilizing radiosodium pertechnetate and the scintillation camera as a practical means of evaluating cerebral vascular disease (CVD) is presented. The normal RA patterns were established in more than 500 patients without clinical evidence of CVD. Detailed study of the arterial and venous perfusion patterns in cases of CVD showed that certain discrete changes can be classified. The RA patterns were evaluated in 143 patients with strokes and in 120 patients with transient ischemic attacks (TIA) and correlated with symptomatology, clinical hospital course and cerebral angiograms. Although static brain scanning in patients with strokes is reportedly positive in approximately 42%, such scans are rarely positive (3%) in patients with TIA. However, by using the RA in combination with static camera imaging, in those patients wth documented stroke, positive studies were obtained in more than 80%, a twofold increase compared to previous experience. In patients with TIA, a tenfold (33%) increase in positive studies was found related to CVD and, in addition, another 7% were positive as mass lesions. The data presented stress the importance of establishing specific criteria for analysis of RA as well as the greatly enhanced sensitivity of this combined approach in detecting CVD.

The diagnostic reliability and specificity of pulmonary angiography and perfusion photoscanning were examined by applying both technics in two series of dogs: one subjected to multiple small pulmonary emboli; the other, to massive embolization. Interpretations of the angiograms and photoscans by two observers were correlated with each other and autopsy data. Analysis disclosed a high degree of agreement between the two technics. Application of both technics, however, led to a greater incidence and accuracy of embolic detection than either method provided alone. Both technics were subject to interpretive errors leading to false positive and false negative diagnoses. The factors promoting such errors are discussed. It is concluded that the two technics are complementary, not competitive, and that each is least reliable in detecting emboli at the extremes of size.

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