Evaluation of the Accuracy of a Video and AI Solution to Measure Lower Leg and Foot Volume.

BACKGROUND AND

OBJECTIVES

Peripheral edema, change in foot volume, is a marker of congestion which is regularly assessed in routine clinical care. A novel video and Artificial Intelligence (AI)-based solution used to measure anatomical parameters, including volume and foot length, Heartfelt HF-1, is compared to the laboratory gold standard (water displacement) and a medical disposable measuring tape.

DESIGN SETTING PARTICIPANTS AND MEASUREMENTS: 58 healthy volunteers were measured with the Heartfelt device; 22 were also measured with the water displacement method and 19 with the medical tape. Bland-Altman analysis was performed for both volumes and foot lengths. Left/right foot differences provided covariance-corrected standard error of measurement (ccSEM) and minimum detectable difference (MDD) for each measurement method.

RESULTS

Heartfelt device measured volumes displayed excellent correlation to the gold standard (water displacement), with Bland-Altman bias of +32mL ±81mL (1 std.dev). Clinically important change in foot volume is approximately 13%. Water displacement yielded ccSEM of ± 32.1mL and MDD of 90mL (6.7% of average foot volume), while the Heartfelt device measurements yielded ccSEM of ±12.6mL and MDD of 35.3mL (2.6% of average foot volume). The majority of differences were attributable to manual positioning of the patient foot in the waterbath.

CONCLUSION

This study finds that in clinical and non-clinical settings, the Heartfelt device measures foot volume and length more precisely than either the water displacement technique or manual foot length measurements using a medical disposable tape, while having an excellent agreement with these methods.