[Cerebral hemorrhage: initial experiences with magnetic resonance imaging].

The authors employed MR imaging to examine 29 hematomas (21 spontaneous, 1 traumatic, 2 vascular malformative, and 5 intratumoral). All images were acquired with a 1.5 T superconducting magnet (Signa, General Electric). The different features hemorrhagic collections may present with on MR images and their temporal evolution depend on their dimension, on the different water content of the hematoma and adjacent tissues, on the peripheral macrophage border, and, above all, on the presence of hemoglobin breakdown products, some of which are paramagnetic. The latter is the most important feature as to the nature of the lesion and allows hematomas to be classified as: 1) Acute (1-7 days): presence of intracellular deoxyhemoglobin. 2) Subacute (8-30 days): 2A, intracellular methemoglobin; 2B, intra- and extracellular methemoglobin; 2C, totally extracellular methemoglobin. 3) Chronic (from 30 days on): thick macrophages hemosiderin rim with/without fluid methemoglobin content. The interpretative difficulties initially met caused the authors to arrange schemes, based on the literature data on the subject, to be used as an useful interpretative tool in most of the cases observed.