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DWI intensity values predict FLAIR lesions in acute ischemic stroke
Vince I Madai1, Ivana Galinovic2, Ulrike Grittner3
1Center for Stroke Research Berlin (CSB), Charité-Universitätsmedizin, Berlin, Germany; Department of Neurology, Charité-Universtitätsmedizin, Berlin, Germany.
Plos One
|March 25, 2014
Summary
A novel diffusion-weighted imaging (DWI) relative signal intensity (rSI) threshold accurately predicts FLAIR lesions in acute stroke, aiding in patient allocation for thrombolysis and serving as a marker for lesion age.
Area of Science:
- Neuroimaging
- Stroke Imaging
- Biomarker Development
Background:
- Diffusion-weighted imaging (DWI) and FLAIR imaging are crucial for acute stroke assessment, particularly for determining eligibility for thrombolysis.
- FLAIR lesion assessment can be challenging, whereas DWI offers high contrast, making it a potential biomarker.
- A DWI-FLAIR mismatch is key for allocating patients within the critical 4.5-hour thrombolysis window.
Purpose of the Study:
- To evaluate the performance of a relative DWI signal intensity (rSI) threshold in predicting FLAIR lesions in acute stroke patients.
- To analyze the association between DWI-rSI and the time from stroke onset.
- To compare the efficacy of DWI-rSI with ADC-rSI in predicting FLAIR lesions.
Main Methods:
- Retrospective, dual-center MR imaging study of acute stroke patients (n=97) with symptom onset ≤12 hours.
- Coregistration of DWI and FLAIR images; identification and delineation of FLAIR lesions by three raters.
- Placement of regions-of-interest (ROIs) on DWI lesions, normalized to the unaffected hemisphere, to calculate DWI-rSI and ADC-rSI.
- Receiver-operating-characteristics (ROC) curve analysis and regression models to assess predictive performance and time association.
Main Results:
- DWI-rSI demonstrated strong performance in predicting FLAIR lesions, with high areas under the curve (AUC) in both 1.5T (0.84) and 3T (0.85) groups.
- Optimal DWI-rSI thresholds were identified (162% for 1.5T, 161% for 3T).
- DWI-rSI showed a significant association with time-from-stroke-onset, unlike ADC-rSI.
Conclusions:
- An easily applicable DWI-rSI threshold accurately identifies FLAIR lesions in acute stroke.
- This DWI-rSI threshold shows potential as a reliable biomarker for estimating lesion age.
- The findings support the use of DWI-rSI for improved patient management in acute stroke settings.
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