Exploring Lower Limb Volume Estimation: Application and Evaluation of Limb Volume Equations with Ideal Circumferential Measurement Intervals.

BACKGROUND: Accurate limb volume measurement is essential for the early detection and continuous monitoring of lower limb lymphedema. We aim to validate the applicability of existing upper limb volume formulas for lower limb volume measurement and to determine the optimal interval for such measurements. METHODS AND RESULTS: Eighty-seven patients who underwent whole lower limb computed tomography (CT) scans due to lower limb edema were enrolled. The volume of the lower limbs was examined using the CT method and the formula method. The measurement range extended from a horizontal line 8 cm below the inferior border of the pubic symphysis to a line 5 cm above the medial malleolus. Differences and consistency between the two methods were compared to identify the optimal measurement interval. There were statistical differences between the formula and CT-calculated volumes at different measurement intervals, with the smallest difference at an interval of 5 cm (Z = -4.664, p < 0.001). Also, good consistency and correlation were shown at 5 cm (intraclass correlation coefficient = 0.971, r = 0.993, p < 0.001). CONCLUSIONS: This study confirms the feasibility and effectiveness of applying upper limb volume formulas to lower limb volume measurement. From a clinical perspective, we recommend a measurement interval of 5 cm as the optimal choice.