Functional image of dynamic computed tomography for the evaluation of cerebral hemodynamics

We report the usefulness of functional image of dynamic computed tomography as a technique for evaluating cerebral hemodynamics. Although the technique itself has been reported, the advance of computer technology has made it possible to obtain high-resolution functional images within only a few minutes. We conducted 70 examinations on 57 patients with cerebral ischemia and correlated the findings with clinical outcome. Those patients whose abnormalities were detected on all corrected mean transit time, time to peak, and peak value images developed massive cortical infarcts. On the other hand, patients with abnormalities detected only on the corrected mean transit time image had only partial low-density lesions on follow-up computed tomograms. Patients with abnormalities detected only on the time to peak image suffered repeated transient ischemic attacks, but follow-up computed tomograms showed no low-density lesion in most cases. Single-photon emission computed tomography with N-isopropyl-p-(123I)iodoamphetamine performed at the time of functional image of dynamic computed tomography showed a high concordance of the findings in many cases, especially those with hyperacute-stage cerebral ischemia, in which the concordance rate was 90.5% (19 of 21). Comparing images constructed from different parameters, functional image of dynamic computed tomography can delineate other than hemodynamic factors, such as extent of the vascular bed or the degree of collateral circulation. Thus, functional image of dynamic computed tomography is a potentially important and useful technique for the further analysis of cerebral hemodynamics.