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Combined diffusion and perfusion MRI with correlation to single-photon emission CT in acute ischemic stroke. Ischemic
J O Karonen1, R L Vanninen, Y Liu
1Department of Clinical Radiology, Clinical Physiology and Nuclear Medicine, Kuopio, Finland. jari.karonen@kuh.fi
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 (<24 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 (P<0.001; n=46) and to 78.5 cm(3) after 1 week (P<0.001; n=42). The perfusion-diffusion mismatch correlated with infarct growth (r=0. 699, P<0.001). The volume of hypoperfusion on the initial PWI correlated with final infarct size (r=0.827, P<0.001). The hypoperfusion volumes detected by PWI and SPECT correlated significantly (r=0.824, P<0.001).
Conclusions:
Combined DWI and PWI can predict infarct enlargement in acute stroke. PWI can detect hypoperfused brain tissue in good agreement with SPECT in acute stroke.
Insights
Combined diffusion-weighted MRI (DWI) and perfusion-weighted MRI (PWI) accurately predict infarct growth in acute ischemic stroke patients. These advanced imaging techniques offer a more effective approach than CT for stroke assessment.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Computed tomography (CT) has limitations in assessing acute ischemic stroke treatments.
- Diffusion-weighted MRI (DWI) detects infarcted brain tissue.
- Perfusion-weighted MRI (PWI) assesses brain perfusion, identifying the ischemic penumbra.
Purpose of the Study:
- To evaluate if combined DWI and PWI can predict infarct growth and final size in acute ischemic stroke (<24 hours).
Main Methods:
- Forty-six acute ischemic stroke patients (no thrombolysis) underwent DWI and PWI on days 1, 2, and 8.
- Twenty-three patients had SPECT scans in the acute phase.
- Lesion volumes measured using DWI, SPECT, and PWI-derived cerebral blood flow maps.
Main Results:
- Mean DWI infarct volume increased significantly from day 1 to day 8 (46.1 cm³ to 78.5 cm³).
- Perfusion-diffusion mismatch strongly correlated with infarct growth (r=0.699, P<0.001).
- Initial PWI hypoperfusion volume strongly correlated with final infarct size (r=0.827, P<0.001).
- PWI and SPECT hypoperfusion volumes showed significant correlation (r=0.824, P<0.001).
Conclusions:
- Combined DWI and PWI effectively predict infarct enlargement in acute ischemic stroke.
- PWI demonstrates good agreement with SPECT in detecting hypoperfused brain tissue in acute stroke.