Abstract TP291: Hematoma Retraction and Perihematoma Hypodensity in Neutral Brain Model of Intracerebral Hemorrhage

Abstract

Listen

Translate article

Background: The temporal evolution of intracerebral hematomas and perihematoma edema in the ultra-early period on computed tomographic (CT) scans in patients with intracerebral hemorrhage (ICH) is not well understood. We aimed to investigate hematoma and perihematoma changes in “neutral brain” models of ICH. Methods: One human and 6 goat cadaveric heads were used as “neutral brains” to provide physical properties of the brain without any biological activity or new bleeding. ICH was induced by slow injection of 4 ml of fresh blood into the right basal ganglia of the goat brains. Similarly, 20 ml of fresh blood was injected deep into the white matter of the human cadaver head in each hemisphere. Serial CT scans of the heads were performed at 0, 1, 3, and 5 hours after inducing ICH. Analyze software (AnalyzeDirect, Overland Park, KS) was used to measure hematoma and perihematoma hypodensity volumes in the baseline and follow up CT scans. Results: The initial hematoma volumes of 11.6 ml and 10.5 ml in the right and the left hemispheres of the human cadaver brain gradually decreased to 6.6 ml and 5.4 ml at 5 hours, showing 43% and 48% retraction of hematoma, respectively. The volume of the perihematoma hypodensity in the right and left hemisphere increased from 2.6 ml and 2.2 ml in the 1 hour follow up CT scans to 4.9 ml and 4.4 ml in the 5 hour CT scan, respectively. Hematoma retraction was also observed in all six ICH models in the goat brains. The mean ICH volume in the goat heads was decreased from 1.49 ml in the baseline CT scan to 1.01 ml in the 5 hour follow up CT scan showing 29.6% hematoma retraction. Perihematoma hypodensity was visualized in 70% of ICH in goat brains, with an increasing mean hypodensity volume of 0.4 ml in the baseline CT scan to 0.8 ml in the 5 hour follow up CT scan. Conclusion: Our study demonstrated that substantial hematoma retraction and perihematoma hypodensity occurs in intracerebral hematomas in the absence of any new bleeding or biological activity of the surrounding brain. Such observations suggest that active bleeding is underestimated in patients with no or small hematoma expansion and our understanding of perihematoma hypodesity needs to be reconsidered.