Evaluation of cerebral perfusion parameters measured by perfusion CT in chronic cerebral ischemia: Comparison with xenon CT

Purpose: The purpose of this work was to evaluate the usefulness of perfusion CT in the evaluation of patients with chronic cerebral ischemia by comparing it with xenon CT (Xe-CT). Method: Cerebral blood flow (CBF) of perfusion CT (CBFper) and time to peak (TTP) were compared with the CBF of Xe-CT (CBFxe) in 18 patients. Cerebral blood volume (CBV) was compared with cerebral vascular reserve (CVR) in 10 of 18 patients who underwent pre- and postacetazolamide Xe-CT. Results: CBFper and TTP demonstrated a high correlation with CBFxe in relative values by side-to-side comparisons (r = 0.743, p < 0.0001 and r = -0.760. p < 0.0001. respectively). There was a negative correlation between relative CBV and relative CVR (r = -0.637, p = 0,0025). Visually, territories with delayed TTP corresponded well to those of decreased CBFxe. but these territories tended to be larger in TTP maps. Conclusion: Perfusion CT is a useful toot to evaluate chronic hemodynamic disturbance and can be an alternative method for those using acetazolamide challenge.