Max Wintermark MD, Presenter: Nothing to Disclose

Patrik Michel, Abstract Co-Author: Nothing to Disclose

Patrick Browaeys MD, Abstract Co-Author: Nothing to Disclose

Reto Antoine Meuli MD, PhD, Abstract Co-Author: Nothing to Disclose

Julien Bogousslavsky MD, Abstract Co-Author: Nothing to Disclose

Pierre Schnyder MD, Abstract Co-Author: Nothing to Disclose

Marc Reichhart, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

Diffusion- (DWI) and perfusion-weighted imaging (PWI) have been used in several drug trials to select stroke patients for acute treatment. The purpose of this study was to evaluate how perfusion-CT (PCT) and CT-angiography (CTA) compare with MRI for the evaluation of the criteria used for treatment decision.

42 acute stroke patients underwent successive CT and MRI examinations in the 3-9 hour time window following symptom onset, 14 being eventually selected for acute stroke treatment based on clinical and MRI criteria. The PCT/CTA and MRI examinations obtained in the 42 patients were independently reviewed by 2 observers for the following criteria: infarct core (PCT infarct or DWI abnormality) 20%, and ischemic involvement of the cortex. The PCT infarct and ischemic penumbra were automatically computed using cerebral blood volume (CBV) and mean transit time (MTT) thresholds reported in the literature. Evaluations of the above-mentioned criteria, and final treatment decision based on these criteria, were compared using Pearson's khi square statistics (alpha).

Agreement between PCT/CTA and MRI was excellent regarding infarct size (alpha=0.89) and cortical involvement (alpha=0.84), and substantial regarding the penumbra/infarct ratio (alpha=0.79). Agreement for treatment decision was excellent (alpha=0.95). Only one patient would have been treated based on MRI, and not treated based on CT. In this patient, the penumbra/infarct ratio was eyeballed as >20% on DWI/PWI, and not fulfilling this condition on PCT. Quantitative PCT measurements revealed that the penumbra/infarct ratio (23%) actually exceeded 20%. The discordance resulted from the eyeballing approach used in the review rather than from the PCT technique itself.

Similar acute stroke treatment decisions would have been made using a PCT/CTA or a MRI approach to assess criteria regarding the arterial occlusion site and the extent of infarct and ischemic penumbra. For the infarct/penumbra ratio evaluation, a quantitative assessment of the PCT results may be more reliable than subjective eyeballing.

Wintermark, M, Michel, P, Browaeys, P, Meuli, R, Bogousslavsky, J, Schnyder, P, Reichhart, M, et al, , Comparison of Perfusion-CT/CT Angiography and MR Imaging in the Selection of Stroke Patients for Acute Treatment.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4413453.html