Introduction/Purpose Utilization of computed tomography perfusion (CTP) to quantify infarct core and penumbra is commonly conducted to determine acute ischemic stroke patient (AIS) eligibility for endovascular intervention procedures. Accurate estimations of infarct and penumbra spatial location are essential as they provide information regarding the location of the vessel occlusion and regions where infarct will advance to. Discrepancies have been known to occur between various CTP software regarding volumetric calculations and spatial location of ischemic tissue due to different perfusion parameters and thresholds being used across software. This study aimed to assess the spatial and volumetric accuracy of RAPID, Sphere, and Vitrea CTP software predicted infarct and penumbra in comparison with final infarct from fluid-attenuation inversion recovery (FLAIR) magnetic resonance imaging (MRI).
Materials and Methods Sixty emergent large vessel occlusion AIS patients treated at a single comprehensive stroke center were included in this study. All patients were required to have undergone initial CTP imaging and 24-hour follow-up FLAIR MRI. Thirty endovascular intervention and 30 medical management patients were included to assess infarct and penumbra tissue, respectively. Endovascular intervention patients were required to have achieved complete successful reperfusion defined as thrombolysis in cerebral infarction 2c/3 to assure all penumbra was salvaged. For medical management patients, it is assumed that all estimated penumbra has converted to infarct on follow-up FLAIR MRI. Within RAPID, Sphere, and Vitrea CTP software, infarct and penumbra tissue was quantified and segmented. Volumetric assessment of CTP infarct and penumbra volumes were conducted using mean infarct differences and mean absolute error (MAE). Spatial accuracy of segmented ischemic tissue was assessed using Dice coefficients, overlap coefficients, sensitivity, specificity, and accuracy metrics.
Results Mean infarct differences, represented as 95% confidence intervals, between FLAIR MRI and each CTP software for each patient cohort are: Intervention patients- RAPID=4.9±6.4 mL, Sphere=-4.5±6.6 mL, Vitrea=3.5±4.9 mL; Medical management patients- RAPID=-40.0±23.3 mL, Sphere=-21.4±17.4 mL, Vitrea=7.4±10.3 mL. MAEs for predicted infarct from each software compared to FLAIR MRI infarct are: Intervention patients- RAPID=13.7 mL, Sphere=12.8 mL, Vitrea=7.3 mL; Medical management patients: RAPID=52.5 mL, Sphere=34.3 mL, Vitrea=18.9 mL. Spatial assessment metrics for ischemic tissue for each patient group and for each software are indicated in table 1.
Conclusions Volumetric results indicate RAPID, Sphere, and Vitrea CTP software all perform similarly in assessing volumetric agreement with final FLAIR MRI infarct for endovascular intervention patients. However, spatial agreement metrics indicate Vitrea performs the best in locating infarct for endovascular intervention patients. For medical management patients, Vitrea software appears the most accurate in assessing penumbra based on volumetric measurements in addition to overlap coefficients.
Disclosures R. Rava: None. M. Mokin: 1; C; NIH grant R21NS109575. 2; C; Canon Medical Systems Corporation, Cerebrotech, Imperative Care. M. Waqas: None. J. Davies: 1; C; National Center for Advancing Translational Sciences of the National Institutes of Health under award number KL2TR001413. 3; C; Penumbra. 4; C; RIST Neurovascular. A. Siddiqui: 2; C; Amnis Therapeutics, Boston Scientific, Canon Medical Systems USA Inc, Cerebrotech Medical Systems Inc, Cerenovus, Corindus Inc, Endostream Medical Ltd., Guidepoint Global Consulting, Imperative Care, Integra LifeSciences Corp, Medtronic, MicroVention, Northwest University–DSMB Chair for HEAT Trial, Penumbra, Q’Apel Medical Inc, Rapid Medical, Rebound Therapeutics Corp, Serenity Medical Inc, Silk Road Medical, StimMed, Stryker, Three Rivers Medical, Inc, VasSol, W.L. Gore & Associates. 4; C; Amnis Therapeutics, Apama Medical, Blink TBI Inc., Buffalo Technology Partner Inc., Cardinal Consultants, Cerebrochtech Medical Systems Inc., Cognition Medical, Endostream Medical Ltd, Imperative Care, International Medical Distribution Partners, Neurovascular Diagnostics Inc., Q’Apel Medical Inc, Rebound Therapeutics Corp, Rist Neurovascular Inc, Serenity Medical Inc, Silk Road Medical, StimMed, Synchron, Three Rivers Medical Inc., Viseon Spine Inc. E. Levy: 2; C; Claret Medical, GLG Consulting, Guidepoint Global, Imperative Care, Medtronic, Rebound, StimMed. 4; C; NeXtGen Biologics, RAPID Medical, Claret Medical, Cognition Medical, Imperative Care (formerly the Stroke Project), Rebound Therapeutics, StimMed, Three Rivers Medical. Y. Hoi: 5; C; Canon Medical Systems Inc. C. Ionita: 1; C; Equipment grant from Canon Medical Systems, Cummings Foundation support. K. Snyder: 2; C; Canon Medical Systems Corporation, Penumbra Inc, Medtronic, Jacobs Institute.
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