Fig. 3.

MR images of intramuscular hematoma four days after injury.

A. Axial spin echo T1-weighted image shows isosignal intensity with peripheral slightly increased signal intensity rim (arrows). Value of central relative signal intensity is 1.1 and that of peripheral relative signal intensity is 1.3. B. Axial T2-weighted image shows heterogeneous high signal intensity lesion (relative signal intensity: 8.27). C. Gradient echo image shows central high signal intensity with a peripheral dark signal rim (central relative signal intensity: 2.73, peripheral relative signal intensity: 0.67). D, E. Microscopic findings of intramuscular hematoma (arrows) (Hematoxylin & Eosin stain, original magnification in D, × 10; in E × 400). After fourth day, hematoma replaces granulation tissue. Necrotic muscle fibers, hemorrhage and inflammatory cells are seen. ○= region of interest for measuring relative signal intensity