TY - JOUR T1 - Contrast-Enhanced MR Imaging in Acute Ischemic Stroke: T2* Measures of Blood-Brain Barrier Permeability and Their Relationship to T1 Estimates and Hemorrhagic Transformation JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 1015 LP - 1022 DO - 10.3174/ajnr.A2003 VL - 31 IS - 6 AU - R.E. Thornhill AU - S. Chen AU - W. Rammo AU - D.J. Mikulis AU - A. Kassner Y1 - 2010/06/01 UR - http://www.ajnr.org/content/31/6/1015.abstract N2 - BACKGROUND AND PURPOSE: rtPA is an effective treatment for AIS, yet it is substantially underused due to the increased risk of HT. Recent work suggests that permeability-related information can be extracted from routine T2*-based perfusion images by measuring the rR of the contrast agent. Given that other T2*-based measures have recently been proposed, the purpose of this study was to evaluate 4 such permeability measures in identifying patients with AIS who will proceed to HT. MATERIALS AND METHODS: Eighteen patients with AIS were examined within a mean of 3.3 ± 1.4 hours postonset. Dynamic T2*-weighted imaging consisted of a single-shot EPI following a bolus of gadodiamide. HT was determined on follow-up CT or MR imaging at 24–72 hours. Mean values of rR, Peak Height, Recovery, as well as Slope were calculated and analyzed on the basis of follow-up HT status. RESULTS: Eight patients proceeded to HT. The mean rR for patients with HT was significantly greater than that for patients without HT (0.22 ± 0.06 versus 0.14 ± 0.06, P = .006), while there was a trend toward decreased %Recovery in patients with HT (76 ± 6 versus 82 ± 11%, P = .092). There was a significant negative correlation between %Recovery and rR (r = −0.88, P < .001). No significant differences or trends were detected with respect to Peak Height or Slope. CONCLUSIONS: Both rR and %Recovery can be readily extracted from a routine perfusion MR imaging dataset and show potential for identifying HT during the acute phase poststroke. ADCapparent diffusion coefficientAISacute ischemic strokeBBBblood-brain barrierDCEdynamic contrast-enhancedΔR2*deltaDWIdiffusion-weighted imagingECASSEuropean Cooperative Acute Stroke StudyEPIecho-planar imagingHIhemorrhagic infarctionHThemorrhagic transformationKPSBBB permeability coefficientmaxmaximumNIHSSNational Institutes of Health Stroke ScalePHparenchymal hematomarRrelative recirculationrtPArecombinant tissue plasminogen activatorSIsignal intensitySlopeslope of the ΔR2* versus time curve between 50 and 60 seconds postinjectionT2*relaxation rate ER -