Development and Validation of a Novel Lymphedema Monitoring System Using a Bodysuit and a Smartphone: Prospective...

Accurate limb circumference measurement is essential for the diagnosis and management of lymphedema, facilitating the objective evaluation of treatment outcomes and early detection of disease progression. Although manual tape measurements are inexpensive and widely used, they are limited by interobserver variability and low reproducibility. Advanced modalities such as computed tomography and magnetic resonance imaging provide high precision but are costly and impractical for routine or home-based use. To overcome these limitations, we developed and validated a novel 3D measurement system that integrates a marker-based bodysuit (ZOZOSUIT2) with a smartphone app, enabling fast, accurate, and reproducible limb circumference assessment.

This study aimed to evaluate the accuracy, repeatability, and time efficiency of the 3D measurement bodysuit and smartphone system compared with those of manual tape measurements in patients with upper and lower limb lymphedema.

This prospective study included 26 patients (n=10 with upper limb lymphedema and n=16 with lower limb lymphedema). Using the ZOZOSUIT2, which contains approximately 20,000 dot markers, 12 full-body photographs were captured with a smartphone, and a 3D model was automatically generated. Circumference values were extracted at 10 standardized points on the upper limb (from the wrist to the top of the upper arm) and 9 on the lower limb (from the ankle to the base of the thigh). Each measurement was repeated 3 times to assess repeatability. Manual tape measurements were used as the reference standard. For each measurement point, the repeatability (intrameasurement variation) and the mean absolute error between the 2 methods were calculated. Measurement time was also recorded for both methods and compared statistically using the Wilcoxon signed-rank test.

Across all measurement points, the median repeatability of the bodysuit smartphone system ranged from 2.2 to 6.4 mm, indicating high reproducibility. When compared with manual measurements, the median of the mean absolute error for upper limb points ranged from 6.7 to 20.5 mm, and for lower limb points ranged from 5.5 to 15.9 mm. Relatively larger discrepancies were observed at the wrist (median 19.8, IQR 15.5-24.1 mm), 5 cm proximal to the wrist (median 20.5, IQR 8.5-28.1 mm), and the base of the thigh (median 15.9, IQR 10.2-25.9 mm). Mean measurement time was significantly shorter with the bodysuit smartphone system (88.2, SD 16.0 seconds) than with manual tape measurement (293.8, SD 58.5 seconds; P<.001).

The bodysuit smartphone system enables rapid, precise, and highly reproducible limb circumference assessment in patients with lymphedema. Despite minor differences at anatomical sites with complex contours, such as the wrist and the thigh base, the overall accuracy and time efficiency were clinically acceptable. This system may serve as a practical and scalable solution for both clinical and home-based lymphedema monitoring, contributing to the objective and standardized assessment of limb volume.