Evaluation of the severity of traumatic rhabdomyolysis using technetium-99m pyrophosphate scintigraphy

A quantitative scoring method was designed to assess the extent of muscle damage. Technetium-99m pyrophosphate (99mTc-PYP) scintigraphy was performed for 9 patients experiencing crush injury in the Chichi (Taiwan) earthquake. The magnitude of muscle uptake of 99mTc-PYP was graded as follows: grade 0, less than bone radioactivity (BRA); grade 1, equal to BRA; grade 2, higher than BRA; or grade 3, greatly higher than BRA. The area of muscle injury was estimated according to the rule of nines. The sum of the muscle injury size multiplied by its corresponding grading was defined as the anterior or posterior score according to the anterior or posterior images. Each image was interpreted by two physicians and average anterior and posterior scores were calculated. The muscle score was defined as the geometric mean of the average anterior and posterior scores. Significant correlations were obtained between the muscle score and duration of time trapped (r = 0.868, p < 0.01), peak serum creatine kinase level (r = 0.866, p < 0.01), peak serum phosphorus level (r = 0.877, p < 0.01) and number of hospital days (r = 0.875, p < 0.01). A negative correlation between the muscle score and blood pH (r = -0.706, p < 0.01) was also observed. We concluded that this scoring method may be used as an adjunct for evaluating the locations of trauma and the severity of crush syndrome, and for predicting the duration of hospital stay.