Abstract T P323: Corticospinal Tract Disruption in Acute Intracerebral Hemorrhage is Unrelated to Baseline Hematoma Volume

Abstract

Background: Acute hematoma volume is the most powerful predictor of poor functional outcome after intracerebral hemorrhage (ICH). Putative reasons for functional deficits include disruption of white matter (WM) tracts. Fractional anisotropy (FA), as assessed with Diffusion Tensor Imaging (DTI), can be used to assess WM integrity. We tested the hypothesis that larger hematoma volumes are associated with lower FA values in the corticospinal tract (CST). Methods: We conducted a prospective cross-sectional imaging study in ICH patients with DTI scans within 7 days of symptom onset. Mean relative FA (rFA) was measured in the entire CST. Hematoma volume was measured using planimetric techniques on acute and follow-up CT scans. Motor function was assessed using a composite of the upper and lower extremity NIHSS subscale (0=normal, 8=hemiplegia) at day 7. Results: Twenty-one ICH patients (mean age 72±14) were imaged with DTI. Median hematoma volume was 9.6 (17.6) ml measured at the 1.8 (2.8) hour CT and 12.2 (35.2) ml at the 25.8 (28.9) hour CT. Median NIHSS motor score was 5 (7) at baseline and 3 (7) at day 7. DTI scans were grouped as acute (median time to imaging: 1.7 (0.78) days) and subacute (time to imaging: 6.9 (2.8) days). Mean acute FA was significantly lower in the CST ispsilateral to the hematoma (0.43±0.03) compared to the contralateral CST (0.48±0.03, p=0.002). Mean subacute FA was also lower in the ipsilateral (0.43 ± 0.04) vs. contralateral CST (0.60±0.15, p=0.002). Acute rFA (r= -0.33, p=0.68) and subacute rFA (r=-0.52, p=0.12) were not correlated with day 7 motor function. Acute hematoma volumes were not related to acute rFA (r= -0.33, p=0.35) or subacute rFA (r= -0.05, p=0.88). Patients with hematoma volumes <9ml had similar subacute rFA (0.96±0.05) to those with hematoma volumes >9ml (0.88±0.07, p=0.072). Acute rFA was similar between patients with hematomas directly adjacent to the CST (0.89±0.07) and those with hematomas separate from the CST (0.97±0.02, p=0.23). Conclusion: DTI demonstrates evidence of CST disruption in acute ICH. However, CST disruption appears to be independent of baseline hematoma volume. Serial assessment of rFA in ICH is required to further define the relationship between larger hematoma volume, rFA and functional outcome.