Early brainstem hemorrhage progression: multi-sequence magnetic resonance imaging and histopathology

According to clinical statistics, the mortality of patients with early brainstem hemorrhage is high. In this study, we established rat models of brainstem hemorrhage by injecting type VII collagenase into the right basotegmental pontine and investigated the pathological changes of early brainstem hemorrhage using multi-sequence magnetic resonance imaging and histopathological methods. We found that brainstem hematoma gradually formed in the injured rats over the first 3 days and then reduced after 7 days. The edema that occurred was mainly of the vasogenic type. No complete myelin sheath structure was found around the focus of the brainstem hemorrhage. The integrity and continuity of nerve fibers gradually deteriorated over the first 7 days. Neuronal degeneration was mild in the first 3 days and then obviously aggravated on the 7^th day. Inflammatory cytokines, interleukin-1β, and tumor necrosis factor α appeared on the 1^st day after intracerebral hemorrhage, reached peak levels on the 3^rd day, and decreased from the 7^th day. Our findings show the characteristics of the progression of early brainstem hemorrhage.