Purpose: There is rising interest in the assessment of perihematoma edema (PHE) as a surrogate measure of the effectiveness of investigational therapies targeting secondary injury after intracerebral hemorrhage (ICH). However, assessment of PHE on CT scans is challenging. We hypothesized that the ratio of the volumes of the ipsilateral-to-contralateral ventricles (IL/CL) can provide an alternative estimate of PHE, and examined the association between IL/CL ventricles and semi-automated quantitative measures of PHE using non-contrast CT scans in subjects with spontaneous ICH.
Methods: We examined the volumetric imaging data from 42 subjects who participated in the HI-DEF trial. We excluded subjects who had an intraventricular hemorrhage or an EVD placed (n=21). Quantitative measurements of ICH, PHE, and ventricular volumes were performed as a routine part of the trial using ANALYZE 11.0 software. We used Spearman correlation coefficient to describe the association between IL/CL and PHE.
Results: A total of 42 CT scans were assessed (21 subjects each with both baseline and post-treatment scans, approximately 5 days later). We observed a significant correlation between PHE volume and IL/CL (r=-0.60, p<0.0001), and ICH volume + surrounding PHE (absolute PHE volume) and IL/CL (r=-0.65, p<0.0001). The correlation between relative PHE (PHE volume divided by ICH volume) and IL/CL was (r=0.50, p=0.009).
Conclusion: IL/CL seems to correlate with quantitative measures of PHE, absolute PHE volumes and, to a lesser extent, relative PHE. Ventricular symmetry might be a suitable alternative to quantitative measures of PHE on CT scans. We plan to validate the potential usefulness of IL/CL and examine its impact on long-term outcomes in the ongoing iDEF trial.