Emission and transmission tomography of the brain in cerebrovascular disease

Transmission and emission computed tomography (T-CT and E-CT, respectively) scans of the brain in 149 patients with cerebrovascular disease were compared to establish the diagnostic accuracy of the two methods. The T-CT scan yielded an overall rate of true-positive results of 80.75% in major infarcts, 80% in intracerebral hematomas, and 75.9% in subarachnoid hemorrhage. In contrast, the percentages of true-positive results yielded by the E-CT scan were 92.3, 55, and 34.5%, respectively, in each type of cerebrovascular disease. The false-negative results obtained with the T-CT scan were higher in infarcts but lower in hematomas and subarachnoid hemorrhage; the reverse was true for the diagnoses obtained with the E-CT scan. The false-positive diagnoses produced by the T-CT scan were high for hemorrhagic strokes compared to those of the E-CT scan. The diagnostic sensitivity of each scan was not affected by the location of the lesion. Thus, the E-CT scan is more sensitive for thromboembolic disease and less so for hemorrhagic types of stroke. The reverse is true for the T-CT scan.