PMC4897327_01
17-year-old male with brachialis muscle rupture. (A) Coronal T1-weighted MRI of the elbow in flexion. The distal aspect of a mass shows intermediate signal with high signal rim consistent with an acute hematoma (H) within the substance of the brachialis muscle (Br). Brt: Brachialis tendon, Bt: Biceps tendon, Ra: Radius. (B) Sagittal T1-weighted MRI of the elbow shows similar findings. (C) Corresponding sagittal STIR-weighted MRI shows high signal within the muscle fibers of the brachialis muscle, consistent with hemorrhage, and intermediate to high signal mass with surrounding rim of low signal consistent with hematoma (H).
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MRI of the right elbow demonstrated a large mass, with signal characteristics of a hematoma, measuring 31.2 mm in greatest diameter within the brachialis muscle (Fig. 1). There was significant edema within the surrounding muscle (Figure 1, Figure 2).
17-year-old male with brachialis muscle rupture. (A) Intermediate-weighted axial MRI through the upper arm showing hemorrhage within the deep portion (D) of the brachialis muscle (presumed deep head) with sparing of the superficial head (S). Margins of the brachialis muscle are outlined in black. (B) Mixed signal-intensity hematoma within the substance of the brachialis muscle (white arrow). Note mild strain in the brachioradialis muscle (black arrow).
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There was significant edema within the surrounding muscle (Figure 1, Figure 2).
17-year-old male with brachialis muscle rupture. MR images obtained 19 days after injury. (A) Axial T1-weighted MRI now shows larger peripheral area of high signal consistent with evolving hematoma. (B) Sagittal T1-weighted and (C) sagittal STIR-weighted MRI show consolidation and decrease in size of hematoma, with resolution of muscle edema.
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This showed interval decrease in size of the hematoma to 18.0 mm, with no evidence of underlying lesion (Fig. 3).