Bahareh Assadi MD, Presenter: Nothing to Disclose

Alberto Carlucci Iaia MD, Abstract Co-Author: Nothing to Disclose

Gianvincenzo Sparacia MD, Abstract Co-Author: Nothing to Disclose

To assess the utility of CT perfusion parameters in predicting the presence of tissue infarction in acute stroke patients.

13 patients (mean age 63.3) with non-hemorrhagic stroke underwent multidetector CT perfusion within 3 hrs. of symptoms' onset. Images were acquired at the basal ganglia over 40 secs, during injection of 90ml of Optiray 320, injected at 9 ml/sec with a 9 sec delay. Z- axis coverage was 20 mm. All patients underwent DWI MR imaging. 4 patients received TPA. CT perfusion data were analyzed, obtaining regions of interests (ROI's) on CBV, CBF and MTT maps, in various parts of the perfusion deficient territory and in the contralateral hemisphere. Areas of restricted diffusion on MRI defined the extent of infarction; such areas were compared to ROI's of CBV, CBF and MTT to establish a possible threshold value that distinguishes between infarcted and viable tissue. Statistical analysis was performed using a 1-way ANOVA test to assess differences in CT Perfusion parameters. ROC analysis was performed to assess the MTT threshold value in predicting the presence of infarcted tissue.

Abnormal CT perfusion parameters were seen in the infarcted tissue and in the viable tissue (penumbra) immediately outside (within 1.5 cm distance) the infarct's outer margin. The average CBF was 24.6 ml/100gm-min in infarcted tissue; 64.8 in the viable tissue adjacent to the infarct (penumbra)and 70.9 in normal tissue. Average CBV was 3.5ml in infarcted tissue, 3.9 in penumbra and 3.0 in normal tissue. Infarcted areas demonstrated significant prolongation of MTT values compared to noninfarcted areas (p<.0001). The average MTT was 9.8 sec in areas of infarction; 5.1 sec in the penumbra; and 3.4 sec in the contralateral control area. A MTT threshold level of 6.5 sec has a 100% positive predictive value(sensitivity 84.6%, specificity 100%, accuracy 92.3%) in establishing the presence of infarcted tissue.

There is significant prolongation of MTT in infarcted tissue of acute stroke patients. Prolongation of MTT to values exceeding 6.5 seconds may distinguish between infarcted and viable tissue.

Assadi, B, Iaia, A, Sparacia, G, Dynamic CT Perfusion in Acute Stroke: Predictive Value of MTT in Assessing Tissue Viability versus Infarction.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4405597.html