Evaluation of early reperfusion and IV tPA therapy using diffusion- and perfusion-weighted MRI

Objective: To characterize the effects of recombinant tissue plasminogen activator (rt-PA) therapy and early reperfusion on diffusion-weighted (DWI) and perfusion-weighted imaging (PWI) changes observed following acute ischemic injury. Methods: Twelve patients were evaluated prospectively using echo planar DWI and bolus tracking PWI. Six patients received IV rt-PA 0.9 mg/kg and were compared with six patients who did not. Patients receiving rt-PA were initially imaged (T1) 3 to 5 hours postictus (mean, 4 hours 20 minutes) whereas those not treated with tissue plasminogen activator (tPA) were imaged 4 to 7 hours postictus (mean, 5 hours, 25 minutes). Follow-up imaging was performed 3 to 6 hours (T2), 24 to 36 hours (T3), 5 to 7 days (T4), and 30 days (T5) after the first scan in all patients. Lesion volumes were measured on both DWI and time-to-peak maps constructed from PW images. Results: PWI was performed successfully at T1 and T3 in 11 of 12 patients. In the group that received IV tPA, initial PWI volumes were less than DWI volumes in five of six patients (83%), whereas only one of five patients (20%) not receiving tPA had PWI < DWI volume (p = 0.08). PWI normalized by 24 to 36 hours (T3) in 6 of 11 patients (early reperfusers), with 5 of 6 of these early reperfusers having received tPA. The aggregate apparent diffusion coefficient (ADC) values for the early reperfusers were consistently higher at T2 (p = 0.04), T3 (p = 0.002), and T4 (p = 0.0005). Five of six patients with early reperfusion demonstrated regions of elevated ADC within the ischemic zone (mean ipsilateral ADC/contralateral ADC, 1.46 ± 0.19) by 24 to 36 hours, whereas none of the nonearly reperfusers showed these regions of elevated ADC (p = 0.015). Conclusion: Early reperfusion is seen more frequently with IV tPA therapy. In addition, the study showed that ADC may undergo early increases that are tied closely to reperfusion, and marked ADC heterogeneity may exist within the same lesion. Early reperfusion is seen more frequently with IV tPA therapy.

[1]  J. Kucharczyk,et al.  Early detection of regional cerebral ischemia in cats: Comparison of diffusion‐ and T2‐weighted MRI and spectroscopy , 1990, Magnetic resonance in medicine.

[2]  J. Zivin.  Diffusion‐weighted MRI for diagnosis and treatment of ischemic stroke , 1997, Annals of neurology.

[3]  Joseph P. Broderick,et al.  Tissue plasminogen activator for acute ischemic stroke. The National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group. , 1995 .

[4]  H. Lutsep,et al.  Clinical utility of diffusion‐weighted magnetic resonance imaging in the assessment of ischemic stroke , 1997, Annals of neurology.

[5]  M. E. Moseley,et al.  Correlation of perfusion- and diffusion-weighted MRI with NIHSS score in acute (<6.5 hour) ischemic stroke , 1998, Neurology.

[6]  M. Kaste,et al.  Intravenous thrombolysis with recombinant tissue plasminogen activator for acute hemispheric stroke. The European Cooperative Acute Stroke Study (ECASS) , 1995, JAMA.

[7]  Diffusion and perfusion imaging for acute stroke. , 1995, Surgical neurology.

[8]  G Di Chiro,et al.  Histopathologic correlates of abnormal water diffusion in cerebral ischemia: diffusion-weighted MR imaging and light and electron microscopic study. , 1993, Radiology.

[9]  P A Narayana,et al.  Cerebrospinal fluid‐suppressed high‐resolution diffusion imaging of human brain , 1997, Magnetic resonance in medicine.

[10]  S M Davis,et al.  Prediction of stroke outcome with echoplanar perfusion- and diffusion-weighted MRI , 1998, Neurology.

[11]  B. Siewert,et al.  Acute human stroke studied by whole brain echo planar diffusion‐weighted magnetic resonance imaging , 1995, Annals of neurology.

[12]  J. Pearlman,et al.  CSF‐suppressed quantitative single‐shot diffusion imaging , 1991, Magnetic resonance in medicine.

[13]  S. Trittmacher,et al.  Hemorrhagic Transformation in Cardioembolic Cerebral Infarction , 1993, Stroke.

[14]  R R Edelman,et al.  Time course of the apparent diffusion coefficient (ADC) abnormality in human stroke , 1997, Neurology.

[15]  Gottfried Schlaug,et al.  Ischemic lesion volumes in acute stroke by diffusion‐weighted magnetic resonance imaging correlate with clinical outcome , 1997, Annals of neurology.

[16]  M E Moseley,et al.  Acute and chronic stroke: navigated spin-echo diffusion-weighted MR imaging. , 1996, Radiology.