Abstract TP8: Apparent Diffusion Coefficientvalue Could Be The New Perspective To Ascertain Effectiveness Of Mechanical Thrombectomy In Large Ischemic Regions

Introduction: Recently, we reported that apparent diffusion coefficient (ADC) values are independently associated with diffusion-weighted imaging (DWI) reversal, and DWI lesions with mean ADC ≥ 520 х 10 -6 mm 2 /s are salvageable by mechanical thrombectomy. These areas regain neurological function. This study aimed to determine the effectiveness of mechanical thrombectomy in especially large ischemic regions with mean ADC ≥ 520 х 10 -6 mm 2 /s. Materials and Methods: We conducted a retrospective cohort study including patients with acute ischemic stroke who underwent endovascular mechanical thrombectomy with successful recanalization between April 2017 and March 2021. DWI reversal was assessed through follow-up magnetic resonance imaging 24 h after treatment. Cases with Alberta stroke program early CT score (ASPECTS)-DWI values 3-5 were enrolled in this study. They were classified as DWI lesions with mean ADC ≥ 520 х 10 -6 mm 2 /s and mean ADC < 520 х 10 -6 mm 2 /s. The primary outcome was modified Rankin scale (mRS) score 0-3 (on a scale of 0-6) at 3 months. Results: In total, ASPECTS-DWI values 3-5 were confirmed in 20 patients. Six patients had DWI lesions with mean ADC ≥ 520 х 10 -6 mm 2 /s, and the remaining 14 patients had DWI lesions with mean ADC < 520 х 10 -6 mm 2 /s. DWI reversals were significantly larger in cases with mean ADC ≥ 520 х 10 -6 mm 2 /s than in those with mean ADC < 520 х 10 -6 mm 2 /s (p=.049). The mRS scores at 3 months in cases with mean ADC ≥ 520 х 10 -6 mm 2 /s and ADC < 520 х 10 -6 mm 2 /s were 3 (0.75-3.75) and 5 (4-6), respectively. mRS score was significantly improved in cases with mean ADC ≥ 520 х 10 -6 mm 2 /s than in cases with mean ADC < 520 х 10 -6 mm 2 /s (p=.011). Conclusions: In large ischemic regions (ASPECTS-DWI: 3-5), DWI lesions with mean ADC ≥ 520 х 10 -6 mm 2 /s are associated with preferable outcomes. The ADC value is easily assessed and a useful tool to predict viable lesions. Therefore, the ADC value could be a new perspective to ascertain the effectiveness of mechanical thrombectomy in large ischemic regions. ABBREVIATIONS: ASPECTS = Alberta stroke program early CT score; ADC = apparent diffusion coefficient; DWI = diffusion-weighted imaging; mRS = modified Rankin scale