Ultrasonography to assess body composition: Relevance of training.

Objective: The aim of this study was to evaluate the relevance of ultrasonography training by non-experts carrying out quadriceps muscle mass assessment.

Methods: Two non-expert evaluators were trained by two radiologists on the basic principles of ultrasonography and quadriceps muscle measurements. Afterward, they performed assessments on 30 healthy volunteers to determine interobserver agreement, considering two landmarks (two-thirds of the femoral distance, and 10 cm above the patella), which were tested by the intraclass correlation coefficient (ICC).

Results: In all, 342 measurements were acquired. Better ICC data were seen for the muscle at two-thirds (ICC = 0.74-0.86) of the landmark than at the 10-cm landmark (ICC = 0.63-0.91). However, the thickness measurements indicated inadequate agreement (ICC = 0.71). The ICC values for both the rectus femoris area and thickness progressively increased when comparing the first 10 measurements with the last 10 for the two-thirds landmark. For the 10-cm landmark, worse data were observed in the last measurements, perhaps due to the increased number of obese volunteers.

Conclusions: Measurements at the 10-cm landmark are more difficult to acquire, especially in the obese. Intensive training for non-expert examiners is mandatory.