Combined Diffusion and Perfusion MRI With Correlation to Single-Photon Emission CT in Acute Ischemic Stroke

Abstract

Background and Purpose-More effective imaging methods are needed to overcome the limitations of CT in the investigation of treatments for acute ischemic stroke. Diffusion-weighted MRI (DWI) is sensitive in detecting infarcted brain tissue, whereas perfusion-weighted MRI (PWI) can detect brain perfusion in the same imaging session. Combining these methods may help in identifying the ischemic penumbra, which is an important concept in the hemodynamics of acute stroke. The purpose of this study was to determine whether combined DWI and PWI in acute (Ͻ24 hours) ischemic stroke can predict infarct growth and final size. Methods-Forty-six patients with acute ischemic stroke underwent DWI and PWI on days 1, 2, and 8. No patient received thrombolysis. Twenty-three patients underwent single-photon emission CT in the acute phase. Lesion volumes were measured from DWI, SPECT, and maps of relative cerebral blood flow calculated from PWI. Results-The mean volume of infarcted tissue detected by DWI increased from 46.1 to 75.6 cm 3 between days 1 and 2 (PϽ0.001; nϭ46) and to 78.5 cm 3 after 1 week (PϽ0.001; nϭ42). The perfusion-diffusion mismatch correlated with infarct growth (rϭ0.699, PϽ0.001).

Ischemic Cerebral Tissue Response to Subventricular Zone Cell Transplantation Measured by Iterative Self-Organizing Data Analysis Technique Algorithm

“…It is worth noting that ischemic tissue with a large T 2 increase 1 day after stroke did not die and survived 6-weeks after stroke, especially for the cell treated animals (comparing Figures 1A with 1F). These results challenge the basic concept in the field of stroke therapy, which an increase in T 2 identifies irreversibly damaged ischemic brain tissue (Welch et al, 1995;Jiang et al, 1997;Jacobs et al, 2000;Karonen et al, 1999;Albers, 1999). Thus, cell transplantation may not only shrink the ischemic lesion ( Figure 4E), but also effectively prevents the pseudo-normal area from undergoing progressive injury.…”

Large Ischemic Lesions on Diffusion-Weighted Imaging Done Before Intravenous Tissue Plasminogen Activator Thrombolysis Predicts a Poor Outcome in Patients With Acute Stroke

“…Perfusionweighted MRI can detect hypoperfused tissue, and the combination of DWI and perfusion-weighted MRI may identify a penumbra area with normal DWI but with perfusionweighted MRI showing hypoperfused tissue. [13][14][15] However, to not delay the start of tPA treatment, we did not include perfusion-weighted MRI examinations in the present study. Second, it is more likely that there is a linear relationship between the amount of early ischemic changes and the functional outcome.…”

Occurrence and Predictors of Futile Recanalization following Endovascular Treatment among Patients with Acute Ischemic Stroke: A Multicenter Study

“…54 Hypoperfusion volumes predicted final infarct volume in 1 study. 55 In another study, hypoperfusion was observed in 42% of patients several hours after IA recanalization for acute stroke (median time to recanalization, 5 hours; range, 4 -8 hours). Most hypoperfused tissue demonstrated infarction on day 7.…”