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Published on: February 16, 2016
Perfusion Imaging Collateral Scores Predict Infarct Growth in Non-Reperfused DEFUSE 3 Patients
Adam MacLellan1, Michael Mlynash1, Stephanie Kemp1
1Stanford University, Departments of Neurology.
Insights
Perfusion imaging collateral profiles, including Hypoperfusion Intensity Ratio (HIR) and cerebral blood volume (CBV) index, predict infarct growth in late-presenting stroke patients. These scores help identify patients with salvageable brain tissue beyond 24 hours.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Late-presenting ischemic stroke patients often have limited reperfusion.
- Assessing collateral circulation is crucial for predicting stroke progression and guiding treatment.
- Perfusion imaging offers detailed insights into tissue perfusion and potential salvageability.
Purpose of the Study:
- To evaluate the association between perfusion imaging collateral profiles and radiographic/clinical outcomes.
- To determine the predictive value of specific perfusion parameters for infarct growth in non-reperfused stroke patients.
- To assess the utility of these profiles in managing late-presenting stroke.
Main Methods:
- Analysis of non-reperfused patients from the DEFUSE 3 clinical trial.
- Calculation of baseline ischemic core, Tmax >6s, and Tmax >10s volumes using RAPID software.
- Definition of substantial infarct growth (>25mL increase) and calculation of Hypoperfusion Intensity Ratio (HIR) and CBV index.
Main Results:
- HIR ≥0.34 and CBV index ≤0.74 optimally predicted substantial infarct growth.
- Patients with unfavorable HIR and CBV index showed significantly greater median infarct growth (108.2mL) compared to those with favorable profiles (21.7mL).
- Baseline perfusion profiles did not correlate with 90-day functional outcomes.
Conclusions:
- Perfusion collateral scores effectively forecast infarct growth in late-presenting, non-reperfused ischemic stroke.
- These parameters can guide transfer decisions and identify patients with persistent salvageable brain tissue beyond 24 hours.
- Further research can refine the use of perfusion imaging in stroke management.
Objective:
This study evaluated the associations of perfusion imaging collateral profiles with radiographic and clinical outcome in late presenting, non-reperfused patients in the DEFUSE 3 clinical trial.
Methods:
Non-reperfused patients in both treatment arms were included. Baseline ischemic core, Tmax >6s, and Tmax >10s perfusion volumes were calculated with RAPID software; infarct volumes obtained 24 hours after randomization were manually determined from DWI or CT. Substantial infarct growth was defined as a >25mL increase between baseline and 24-hour follow-up. Hypoperfusion Intensity Ratio (HIR) was defined as the proportion of the Tmax >6s lesion with Tmax >10s delay; CBV index was calculated by RAPID from mean CBV values within the Tmax >6s lesion compared to regions of normal CBV.
Results:
Eighty-four patients were included. ROC analysis showed HIR ≥0.34 (AUC=0.68) and CBV index ≤0.74 (AUC=0.72) optimally predicted substantial infarct growth in follow-up. Median growth was 23.4 versus 73.2mL with HIR threshold of 0.34 (p=0.005), and 24.3 versus 58.7mL with CBV index threshold of 0.74 (p=0.004). If baseline HIR and CBV index were both favorable, median growth was 21.7mL, 40.9mL if one was favorable, and 108.2mL if both were unfavorable (p<0.001). Baseline perfusion profile was not associated with 90-day functional outcome.
Conclusions:
Perfusion collateral scores forecast infarct growth in late presenting, non-reperfused ischemic stroke patients. These parameters may be useful for guiding transfer decisions, such as need for repeat imaging upon thrombectomy center arrival, and may help identify slow progressing patients more likely to have persistent salvageable ischemic tissue beyond 24 hours.
