The Use of Computed Tomography in Assessing Muscle Cross-sectional Area, and the Relationship between Cross-sectional Area and Strength.

The estimation of muscle cross-sectional area (CSA) by anthropometric measurements is insensitive for objective clinical research. However computed tomography (CT) enables specific muscle imaging for accurate CSA determination. This study, involving 15 males with previous knee injuries, examined the repeatability of bilateral CT in calculating mid-thigh muscle densities (Houndsfield units: HU) and quadriceps atrophy. Significant differences between limbs in strength (p<0.0001), CSA (p<0.001) and HU (p<0.05) were observed. Prior to a four week electro-motor stimulation (EMS) programme, a significant correlation between force and quadriceps CSA existed which diminished over time. Neurogenic contributions to improved strength were demonstrated in the absence of increased CSA. These data suggest CSA is not a reliable predictor of strength potential in atrophic muscle. Computed tomography scanning provides an accurate, repeatable method for standardized tissue density and muscle CSA assessment.