In vitro modeling of the magnetic resonance appearance of cerebral hemorrhage.

In vitro studies provide a framework for understanding the biophysical mechanisms in the evolution of the magnetic resonance (MR) appearance of cerebral hematomas. Varying concentrations of oxyhemoglobin, deoxyhemoglobin and methemoglobin in saline or in concentrated bovine serum albumin solutions were imaged at 1.5 T, allowing assessment of the relative relaxation effects of heme oxidation state, oxygenation, and protein concentration. The findings demonstrate the importance of susceptibility effects arising from local field heterogeneity in producing T2 shortening upon varying hemoglobin concentration for intracellular deoxyhemoglobin and methemoglobin. Correlation between the clinically observed MR appearance of acute and subacute hematomas with these in vitro models is presented.