The Efficacy of Perfusion CT to Determine the Indication of Acute Thrombolytic Therapy

We developed a method for quantitative measurement of cerebral blood flow (CBF) using multi slice dynamic computed tomography (CT) and iodinated contrast material based on the box-MTF model. We investigated whether it is possible to determine an indication for acute thrombolytic therapy using this method. Initially we examined the correlation between CBF measured by this method and that by SPECT using 99mTC-ECD in 10 patients with chronic ischemic cerebrovascular diseases. The correlationship between them showed CBF (SPECT)=0.79×CBF (Perfusion CT) and its correlation coefficient was 0.60. To examine the reproducibility, CBF was measured twice at 5-minute intervals including 1 overlapping slice in 9 patients. The CBF value in the overlapped slice was compared between 2 examinations. Finally, the correlation between CBF and back pressure was examined in 10 patients with acute cerebral embolism. A fairly good correlation was obtained from these 2 studies. The correlation coefficient of the latter 2 studies was 0.80 and 0.86 respectively. It takes nearly 1 minute for dynamic scan, and about 15 minutes for data analysis. This is a significant advantage for the evaluation of CBF in acute cerebrovascular disease. We conclude that our method to measure CBF using a multi slice dynamic CT scanner and box-MTF model is useful to determine the indication for acute thrombolytic therapy.