Reproducibility of quantitative CT perfusion imaging

The ability to demonstrate regions of abnormal cerebral brood flow in the s etting of acute stroke is of diagnostic and prognostic importance. It may a lso influence therapeutic strategies. The advantage of CT perfusion imaging is its ability to give quantifiable measurements of cerebral blood flow on any modern CT machine without the need to buy specialized equipment. The a im was to assess day-to-day variability of values of cerebral blood volume obtained with this technique. Seven patients with cerebral gliomas were stu died using dynamic CT perfusion imaging on two occasions, approximately 24 h apart to reduce variability from diurnal variations. Regions of interest were produced in predominately middle cerebral artery locations in both hem ispheres on the first and second CT perfusion studies. Absolute values for cerebral blood flow were produced for these regions and were correlated wit h flows obtained in the same regions of interest on the follow-up study. Th e Pearson correlation coefficient obtained was 0.884. CT perfusion imaging is easily performed on conventional modern CT equipment and demonstrates li ttle variability in measures of absolute cerebral blood flow within individ uals when studied on two occasions within 24 h.