Pamela Whitney Schaefer MD, Presenter: Nothing to Disclose

Elizabeth R. Barak MD, Abstract Co-Author: Nothing to Disclose

Shahmir Kamalian MD, Abstract Co-Author: Nothing to Disclose

Leila Rezai-Gharai MD, Abstract Co-Author: Nothing to Disclose

Ramon Gilberto Gonzalez MD, PhD, Abstract Co-Author: Grant, Bayer AG (Berlex Inc)

Michael H. Lev MD, Abstract Co-Author: Speaker, General Electric Company Advisory Board, General Electric Company Research support, General Electric Company Speaker, Bracco Group Advisory Board, Bracco Group Advisory Board, CoAxia, Inc

3 inclusion criteria for trials aimed at extending the time window for IV thrombolysis beyond 3 hours are:(1)MTT lesion >2 cm, (2)core 20%. We sought to determine:(1)the correlation between quantitative CT and MR lesion measurements, and (2)whether the difference between measurements would alter the decision to enroll patients in trials.

48 patients with acute MCA stroke, first imaged within 8.3 hrs of onset, who underwent CTP and DWI/PWI within 3 hours of each other were included. DWI and MR-MTT lesions were visually segmented with commercial software. The CT-CBV and CT-MTT lesions were automatically segmented with commercial software, using a relative CBV threshold of 0.66 and a relative MTT threshold of 1.50. CTP coverage was 1 cm in 4 cases, 2 cm in 14, 4 cm in 25, and 8 cm in 5. Percent mismatch, [(MTT- DWI)/MTT x100, and Pearson correlation coefficients were calculated.

Mean DWI lesion was 49(0-247)cc and mean CT-CBV lesion was 23(0-156)cc, r=0.91(p2 cc. In 46/48, MRI and CTP agreed for determining 20% mismatch. In 44/48, MRI and CTP agreed for determining core 100cc’s. In 41/48 cases CTP and MRP aggreed on clinical trial enrollment. Discrepancies were due to spurious CTP measurement in 1 case and inadequate CTP coverage in 6 cases.

Quantitative core and penumbra measurements are highly correlated for MRP and CTP imaging and improve with increased CTP coverage. Inclusion criteria have good agreeement between CTP and MRP and most discrepancies are the result of inadequate CTP coverage.

Although MR is currently the imaging method of choice for enrolling patients in trials, CT is reliable and may be more practical to perform in acute stroke patients.

Schaefer, P, Barak, E, Kamalian, S, Rezai-Gharai, L, Gonzalez, R, Lev, M, Quantitative Assessment of Core/Penumbra Mismatch in Acute Stroke: CT and MR Perfusion Imaging Are Highly Correlated (When Coverage Is Sufficient!).  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5007031.html