Quantitative evaluation for secondary injury to perihematoma of hypertensive cerebral hemorrhage by functional MR and correlation analysis with ischemic factors

Objectives: To analyse quantitatively for the secondary injury to the perihematoma region of intracerebral hemorrhage (ICH) patients by functional MR imaging technique. Methods: 35 ICH patients were recruited and performed T1, T2, perfusion weight imaging (PWI), diffusion weight imaging (DWI) and FLAIR sequence scanning. Hematoma volume and edema volume of perihematomal area as well as parameters of blood volume [regional cerebral blood volume (rCBV), mean transit time (MTT)] alteration were calculated. Results: Varied blood flow decline was detected in the patients on the perihematoma sides, compared with the corresponding area of the opposite sides. There was significant difference of rCBV and MTT (p=0.00) and mild negative correlation between rCBV and hematoma volume (p=0.00) among groups; edema volume of perihematoma region and hematoma volume showed a linear correlation (p=0.00). Moreover, positive correlation between edema intensity and rCBV was detected, (p=0.00); the most significant perihematoma edema was in the group of day 10 to day 14; the lowest rCBV occurred in the early stage. (days 2 - 5 from symptom onset). Conclusion: We have concluded that rCBV and MTT of perihematoma region decreased remarkably compared with the contralateral side, and the decline would last over 3 weeks. Quantitative research suggested edema intensity is closely related with rCBV. We believe that the reduced regional blood flow of perihematoma contributes to the secondary ischemic injury of perihematoma tissue. However, the peak of edema would appear later than the onset of the peak of ischemia, it suggests that edema surrounding the hematoma is not only the result from the single ischemic factor, but also results from multiple disadvantage mechanisms.