Tc99m-sestamibi thigh SPECT/CT images for noninvasive assessment of skeletal muscle injury in carbon monoxide intoxication with clinical and pathological correlation

Purpose: Muscle weakness has been repeatedly reported in patients with carbon monoxide (CO) intoxication. In animal models, CO intoxication has been linked with mitochondrial electron transport dysfunction. The objectives of the present study were to use Tc-99m sestamibi thigh single-photon emission computed tomography/computed tomography (SPECT/CT) to evaluate the mitochondrial status in patients with CO intoxication, correlate this with clinical parameters, and compare with age-matched controls. Materials and Methods A total of 25 patients with delayed sequelae after CO intoxication (range: 1-60 months) and 17 sex- and age-matched healthy volunteers underwent Tc-99m sestamibi thigh SPECT/CT. Cognitive evaluation and muscle power according to medical research council (MRC) grading were collected. Both visual scoring from planar images and automatic volumetric analysis were used to rate the Tc-99m sestamibi uptake level. Result: The visual scores showed that 14 patients (56.0%) were scored as moderate-to-severe decrement. Volumetric analysis showed that a significant Tc99m-sestamibi uptake decrement was found in the CO intoxication group as compared with the controls, and 16 patients (64.0%) had uptakes below 1 standard deviation of the control group. In the CO group, the muscle power but not the cognitive evaluation correlated with Tc-99m sestamibi uptake in muscles. The decrement of muscle Tc99m-sestamibi uptake was related to mitochondria swelling, increased mitochondrial numbers, and type II muscle atrophy in 1 patient. Conclusion: In this study, we demonstrated that patients with CO intoxication sustained defective mitochondrial metabolism in skeletal muscles as revealed by a decrement in Tc-99m sestamibi uptake either by visual or semiquantification of thigh SPECT/CT. Tc-99m sestamibi scanning provided noninvasive measurement of mitochondrial injury in muscles after CO intoxication and the correlation with clinical parameters was good.