Asymmetry of Intracranial Hemodynamics as an Indicator of Mass Effect in Acute Intracerebral Hemorrhage

Background and Purpose Hematoma volume is an important determinant of outcome and predictor of clinical deterioration in patients with intracerebral hemorrhage. In many cases, worsening results from herniation due to compartmentalized pressure gradients. We used transcranial Doppler sonography (TCD) to assess the impact of hematoma volume on symmetry of intracranial hemodynamics in patients with acute intracerebral hemorrhage. The goal was to evaluate TCD as a noninvasive method for monitoring compartmentalized mass effect. Methods TCD was performed an average of 1.1 days (range, 0 to 3 days) after onset in 30 patients with supratentorial intracerebral hemorrhage. Hematoma, hematoma+edema, and intraventricular hemorrhage volumes were calculated from admission CT scans using computerized planimetry and were compared with combined TCD values from the middle cerebral and internal carotid arteries. Results Ipsilateral pulsatility indexes were consistently elevated and mean velocities consistently depressed when intracerebral hemorrhage volumes exceeded 25 mL. Compared with patients with small hemorrhages, those with large hemorrhages (≥25 mL, n=10) had significantly higher ipsilateral pulsatility indexes (1.72 versus 1.13, P <.0001) and higher ratios of ipsilateral-to-contralateral pulsatility (1.29 versus 1.06, P =.001). The ratio of ipsilateral-to-contralateral mean velocity was similarly reduced in patients with large versus small hemorrhages (0.87 versus 1.06, P =.01), but this effect was less pronounced. In a multiple regression analysis, ipsilateral and contralateral pulsatility indexes correlated primarily with intraventricular hemorrhage volume ( P <.001), whereas the ratio of ipsilateral-to-contralateral pulsatility correlated with total hemispheric lesion (hematoma+edema) volume ( P =.003). Conclusions Asymmetry of intracranial hemodynamics as assessed by TCD occurs when intracerebral hemorrhage volumes exceed 25 mL. Alterations of pulsatility index reflect intracranial lesion volume more reliably than mean velocity. Although pulsatility is strongly influenced by the presence of intraventricular blood, elevated ratios of ipsilateral-to-contralateral pulsatility correlate primarily with hemispheric lesion volume and may reflect compartmentalized intracranial pressure gradients.