Abstract W MP114: Impact of Blood Removal on Perihematomal Apparent Diffusion Coefficients in Patients Treated with Minimally Invasive Surgery Plus rt-PA

Abstract

Introduction: Novel procedures such as minimally invasive surgery (MIS) and rt-PA administration can effectively reduce not only blood volume, but also perihematomal edema (PHE) formation in stroke patients. In order to quantify the amount of blood brain barrier (BBB) disruption within this perihematomal region, apparent diffusion coefficient (ADC) maps can be used. We hypothesized that hematoma removal in MIS treated patients would result in lower ADC values when compared to patients receiving standard medical care. Methods: The impact of hematoma removal on ADC elevation was evaluated in patients from MISTIE II using MRI. FLAIR and GRE sequences were used at baseline (D1) and one-week (D7) post ictus, to delineate total lesion (hematoma plus PHE) and hematoma regions. The ROIs of the two sequences were subtracted leaving the PHE region to be transferred to the ADC map and averaged for each patient at both time points. Results: Fourteen surgical and 10 medical patients were analyzed. Time between D1 and D7 was similar between MIS, 7.28(1.68) days, and medical patients, 6.91(0.84) days (p=0.49); as was baseline hematoma volume, 41.9(17.9) cc and 35.2 (14.3) cc, respectively (p=0.32). Successful clot removal was demonstrated with a group difference in end of treatment ICH volume, MIS 15.2(8.9), medical 32.3(10.3) (p<0.001). Finally, the median change in average ADC for the MIS cohort, a decrease of 30.5 mm2/sec, was significantly lower when compared to the median change for the medical cohort, an increase of 75.7 mm2/sec (p=0.004). Conclusion: Hematoma removal has been previously reported to significantly reduce both ICH and PHE volume. Here, we report the effect of clot removal on ADC elevation. A decrease in ADC between D1 and D7 in the MIS cohort when compared to the increase in the medical cohort suggests that MIS plus rt-PA mitigates BBB disruption, and in turn, provides an explanation for the difference in formation of perihematomal edema.