Effect of supervision on ultrasonographic measurements. A blinded randomized cross-over study

Musculoskeletal ultrasound is becoming an increasingly popular clinical tool in the hands of physiatrists. Herewith, although the role of direct supervision (by an expert) is universally recognized as the core element for appropriate ultrasound training, to our best notice, its impact on ultrasonographic measurements has not been studied quantitatively in the hitherto literature.

To quantify the effect of supervision in the early period of musculoskeletal ultrasound training by using three different tissues (muscle-cartilage-tendon) as models.

A blinded randomized cross-over study.

Physical Medicine and Rehabilitation Department of a University Hospital.

A total of 9 sonographers (8 novice and 1 expert) were involved whereby the novice sonographers were randomly divided into two groups; Group A (N.=4) and Group B (N.=4).

All sonographers performed three thickness measurements; medial head of the gastrocnemius muscle, patellar tendon and femoral cartilage on the left lower limb of the same subject. The expert supervised Group A in the first half of the study (9 days), and Group B in the second half (9 days). Throughout the study period, all the participants were blinded to the data. Relative effectiveness, expert effect, order effect, treatment-period effect were studied for cross-over variance analysis.

For all the three sites, measurements under the supervision of the expert were significantly different than those without him -p values pertaining to relative effectiveness, expert effect were 0.014, 0.013 for femoral cartilage; <0.001, <0.001 for gastrocnemius and <0.001, <0.001 for patellar tendon, respectively). For gastrocnemius muscle measurements, studying with the expert in the second half of the study (vs in the first half) was better concerning the precision of the measurements (order effect P<0.001).

Supervision during measurements of novice sonographers is crucial and their data should otherwise be interpreted attentively.