MRI quantitative study and pathologic analysis of crush injury in rabbit hind limb muscles.

ABSTRACT

BACKGROUND: To explore the value of quantitative magnetic resonance imaging (i.e., T2 map technique) in the diagnosis of crush injury in rabbit hind limb muscles. MATERIALS AND METHODS: We established a rabbit hind limb crush injury model and performed examinations on magnetic resonance imaging (MRI) (T1WI, T2WI, and T2 map), muscle pathology, serum level of muscular troponin (sTnI), and urine myoglobin (Myo) at 1, 3, 7, 14, and 30 d after injury to investigate the correlation of MRI, library examination, and histopathology. RESULTS: T2WI of the injured muscle showed high signal intensity at 1, 3, and 7 d after crush injury and the T2 value continued to rise. The pathologic findings of the muscle included swollen and ruptured cells, expanded extra-cellular space, inflammatory reactions, and fine muscle fiber regeneration. The serum sTnI and urine Myo were high. At 14 d, these indices returned to normal gradually. The T2WI changes and T2 value were positively associated with the pathological changes of the muscles, serum sTnI and urine Myo. However, the signal intensity of T1WI did not vary significantly at different time points. CONCLUSION: T2WI and T2 value from T2 mapping are very useful methods of choice to evaluate the distribution and extension of the affected muscles. The high signal intensity on T2WI of the affected muscles after crush injury may be due to an increased extracellular space, local inflammation, and incomplete muscle fiber regeneration.