Useful parameters utilizing perfusion CT study to evaluate the hemodynamic status in chronic ischemic stroke patients

Objective : Perfusion-computed tomography (CT) is useful and quick diagnostic tool for evaluating ischemic stroke patients. We evaluated three measurement maps, cerebral blood flow (CBF), cerebral blood volume (CBV) and time to peak (TTP) for their usefulness in deciding on revascularization surgery using CT parameters after single photon emission computed tomography (SPECT) findings in chronic steno-occlusive disease patients. Methods : We retrospectively investigated 47 patients with unilateral internal carotid artery (ICA) or middle cerebral artery (MCA) steno-occlusive disease . All patients underwent digital subtraction angiography (DSA) as well as an acetazolamide challenge with SPECT and perfusion CT. Patients who showed decreased reserve capacity with a Diamox challenge were classified in the positive group, whereas patients who had no difference in reserve capacity were placed in the negative group. Results : Thirty-one patients were positive and the remaining 16 were negative. Differences in rCBV and rCBF parameters between normal cerebral hemispheres and cerebral hemispheres with steno-occlusive disease did not correlate with SPECT results, but TTP values did. SPECT results seemed relevant when TTP differences between hemispheres with normal and steno-occlusive disease were more than 1.55 times. Conclusion : Perfusion CT is a useful tool for the rapid, adequate diagnosis of large territorial infarcts, and the TTP map of perfusion CT is a sensitive and reliable parameter to show the status of collateral circulation in chronic cerebrovascular ischemic disease.