Comparison of Shear-Wave Elastography USG and CT: Composition Analysis of Rectus Femoris Muscle in Healthy Adults and Chronic Kidney Disease Patients.

Purpose: This study aimed to compare shear-wave elastography (SWE) USG and composition analysis of CT on the right mid-rectus femoris muscle (RF) in both healthy adults and chronic kidney disease (CKD) patients.

Methods: Sixty-three healthy adults and 22 CKD patients were included. One musculoskeletal radiologist performed right RF SWE USG, while two radiologists measured shear-wave velocity (SWV) from the same SWE images. CT scan was performed, and muscle composition was measured using imageJ, categorized into four HU-based compositions. Interobserver agreement for SWV between two readers was evaluated. Correlations between SWV and CT compositions were analyzed using Pearson's or Spearman's correlation.

Results: SWV of healthy group was significantly higher than CKD group by each reader (p = 0.030 and 0.038). The percentage of low-density muscle was higher in CKD group than healthy group (p < 0.001), and the percentage of normal density muscle was higher in healthy group than CKD (p < 0.001) by each reader. Interobserver agreement of SWV by the two readers was almost perfect in both groups (k = 0.957-0.984, 0.959-0.993). There was a statistically significant correlation between SWV and the percentage of normal density muscle on CT in both healthy adults and CKD patient groups (Reader 1, r = 0.318-0.480, p = 0.001 and 0.024; Reader 2, r = 0.511-0.518, p < 0.001 and p = 0.013).

Conclusions: SWV demonstrated a significant correlation with the percentage of normal density muscle on CT in both healthy adults and CKD patients by each reader. SWE provides a radiation-free approach that may offer an objective method for evaluating muscle quality, potentially making it an option for muscle monitoring.