S W Atlas1, K R Thulborn. 1. Department of Radiology, Mount Sinai School of Medicine, New York, USA.
Abstract
BACKGROUND AND PURPOSE: The detection of hemorrhage in acutely ill patients is crucial to clinical management. The MR features that allow diagnosis of intracerebral hematomas of less than 24 hours' duration are described and the mechanistic basis of these features is investigated. METHODS: The clinical MR features of seven confirmed hyperacute intracerebral hematomas were compared with those of experimentally induced hematomas in a rat model in which detailed analyses of iron metabolism and morphometry were performed. RESULTS: In all patients and all animals, a hypointense rim on T2-weighted spin-echo images that was less marked on T1-weighted spin-echo images was seen surrounding a central isointense or heterogeneous region of hyperacute hematoma. Histologically, the clot showed interdigitation of intact erythrocytes and tissue at the hematoma-tissue interface without significant hemosiderin, ferritin, or phagocytic activity. Biochemically, the iron from the extravasated blood was present only as heme proteins within the first 24 hours. CONCLUSION: The hypointense rim on T2-weighted images, and to a lesser extent on T1-weighted images, is a distinctive feature of hyperacute hematoma. This pattern is consistent with magnetic susceptibility variations of paramagnetic deoxygenated hemoglobin within intact erythrocytes at a microscopically irregular tissue-clot interface. The detection of hemorrhage is important in the management of patients with acute stroke.
BACKGROUND AND PURPOSE: The detection of hemorrhage in acutely ill patients is crucial to clinical management. The MR features that allow diagnosis of intracerebral hematomas of less than 24 hours' duration are described and the mechanistic basis of these features is investigated. METHODS: The clinical MR features of seven confirmed hyperacute intracerebral hematomas were compared with those of experimentally induced hematomas in a rat model in which detailed analyses of iron metabolism and morphometry were performed. RESULTS: In all patients and all animals, a hypointense rim on T2-weighted spin-echo images that was less marked on T1-weighted spin-echo images was seen surrounding a central isointense or heterogeneous region of hyperacute hematoma. Histologically, the clot showed interdigitation of intact erythrocytes and tissue at the hematoma-tissue interface without significant hemosiderin, ferritin, or phagocytic activity. Biochemically, the iron from the extravasated blood was present only as heme proteins within the first 24 hours. CONCLUSION: The hypointense rim on T2-weighted images, and to a lesser extent on T1-weighted images, is a distinctive feature of hyperacute hematoma. This pattern is consistent with magnetic susceptibility variations of paramagnetic deoxygenated hemoglobin within intact erythrocytes at a microscopically irregular tissue-clot interface. The detection of hemorrhage is important in the management of patients with acute stroke.
Authors: Julio A Chalela; Chelsea S Kidwell; Lauren M Nentwich; Marie Luby; John A Butman; Andrew M Demchuk; Michael D Hill; Nicholas Patronas; Lawrence Latour; Steven Warach Journal: Lancet Date: 2007-01-27 Impact factor: 79.321
Authors: J Perl; J A Tkach; M Porras-Jimenez; M Lieber; N Obuchowski; J S Ross; X P Ding; P M Ruggieri; D M Shearer; K Khajavi; T J Masaryk Journal: AJNR Am J Neuroradiol Date: 1999 Nov-Dec Impact factor: 3.825