High-field magnetic resonance imaging of intracranial hematomas.

One hundred intracranial hematomas aged 1 day to greater than 4 years old were imaged at 1.5 Tesla using T1- and T2-weighted spin-echo pulse sequences. Characteristic intensity patterns seen in the evolution of hematomas were identical to those preliminarily reported in 20 hematomas. They allow staging of a hematoma into acute (less than 1 week old), subacute (between 1 week and 1 month old), and chronic (several months to several years old). The mechanisms suspected to be responsible for these intensity patterns were confirmed by in vitro nuclear magnetic relaxometry of blood, ferritin and hemosiderotic spleen samples performed on a variable field spectrometer at 0.19 to 1.4 Tesla. High-field magnetic resonance imaging is sensitive and specific for hemorrhage in all of its stages of evolution as well as to the ambient oxygen tension of acute hematomas.