Changes in Muscle Mass in Patients With Renal Transplants Based on Ultrasound: A Prospective Study.

Objectives: This original research aimed to investigate the value of ultrasound (US), including grayscale US and shear wave elastography (SWE), in quantitatively evaluating muscle mass after kidney transplantation.

Methods: A total of 52 patients and 54 healthy control participants were recruited. High-frequency US was used to evaluate the echo intensity and muscle morphologic features. Muscle stiffness in the rectus femoris was assessed with SWE. Interclass and intraclass correlation coefficients were used for evaluating measurement reliability. The diagnostic performance of SWE was determined by a receiver operating characteristic curve analysis.

Results: The intraobserver and interobserver repeatability was excellent (all correlation coefficients >0.940; P < .05). The best evaluation point after right iliac fossa transplantation was at the lower third of the right leg. In patients, the skin (0.154 versus 0.192 cm) and rectus femoris (0.700 versus 0.905 cm) were thinner, and the pinnate angle (6.500° versus 8.000°) and area (0.965 versus 1.270 cm ) were smaller (all P < .05). The US results showed that, compared with the controls, all patients' rectus femoris echo intensity (P < .001 in the transverse section) and elastic modulus (P < .001 in the Young modulus and shear wave speed) increased significantly. The cutoff values were 10.05 and 10.37, and the areas under the receiver operating characteristic curves were 0.843 and 0.845 for predicting kidney transplant and sarcopenia, respectively.

Conclusions: This noninvasive and convenient technique might be effective for objectively evaluating the muscle mass of patients after kidney transplantation.