Decreased perihematomal edema in thrombolysis-related intracerebral hemorrhage compared with spontaneous intracerebral hemorrhage

Background and Purpose-Intracerebral hemorrhage (ICH) is a highly morbid di sease process. Perihematomal edema is reported to contribute to clinical de terioration and death. Recent experimental observations indicate that clott ing of the intrahematomal blood is the essential prerequisite for hyperacut e perihematomal edema formation rather than blood-brain barrier disruption. Methods-We compared a series of patients with spontaneous ICH (SICH) to a s eries of patients with thrombolysis-related ICH (TICH), All patients were i maged within 3 hours of clinical onset. We reviewed relevant neuroimaging f eatures, emphasizing and quantifying perihematomal edema. We then analyzed clinical and radiological differences between the 2 ICH types and determine d whether these factors were associated with perihematomal edema. Results-TICHs contained visible perihematomal edema less than half as often as SICHs (31% versus 69%, P<0.001) and had both lower absolute edema volum es (0 cc [25th, 75th percentiles: 0, 6] versus 6 cc [0, 13], P<0.0001) and relative edema volumes (0.16 [0.10, 0.33] versus 0.55 [0.40, 0.83], P<0.000 1), Compared with SICHs, TICHs were 3 times larger in volume (median [25th, 75th percentiles] volume 69 cc [30, 106] versus 21 cc [8, 45], P<0.0001), 4 times more frequently lobar in location (62% versus 15%, P<0.001), 80 tim es more frequently contained blood-fluid level(s) (86% versus 1%, P<0.001), and were more frequently multifocal (22% versus 0%, P<0.001), Conclusions-The striking qualitative and quantitative lack of perihematomal edema observed in the thrombolysis-related ICHs compared with the SICHs pr ovides the first substantial, although indirect, human evidence that intrah ematomal blood clotting is a plausible pathogenetic factor in hyperacute pe rihematomal edema formation.