Raju Seshadri, Matheson Sara, Smith Slade, Owens Jack, Adaikkappan Vijay M
The RANE Center for Venous & Lymphatic Diseases, Jackson, MS.
The RANE Center for Venous & Lymphatic Diseases, Jackson, MS.
J Vasc Surg Venous Lymphat Disord. 2025 Sep;13(5):102275. doi: 10.1016/j.jvsv.2025.102275. Epub 2025 Jun 6.
Quantifying limb edema is challenging owing to the lack of an easily accessible clinical technique. This study evaluates the reproducibility of an iPad-based three-dimensional (3D) scanning system for lower limb volumetry and identifies factors influencing measurement variability.
Twenty limbs from 10 healthy volunteers were scanned using an iPad-based Structure Sensor and software. Initial scans followed standard manufacturer instructions, but high variance rendered data unsuitable for clinical use. To improve accuracy, a standardized scanning protocol was developed, incorporating anatomical calibration, scanning distance standardization, and scanning time control. A 254-mm calf segment was defined using a 3D marker placed on the medial malleolus to ensure consistent volume measurement. The scanning distance was fixed between 50 and 59 cm to reduce zoom parallax errors, and scans were conducted after 3 pm to minimize diurnal volume fluctuations. Multiple technicians performed repeat scans on the same limb to assess intraobserver and interobserver scan reliability.
Implementing the standardized protocol significantly decreased measurement variability. Defining a consistent anatomical scan region improved reproducibility, with the mean volume difference decreasing from 4.7% ± 3.6% to 2.1% ± 1.6%. Standardizing scanning distance reduced zoom-related errors, improving measurement consistency from 2.6% ± 1.5% to 2.0% ± 1.2% (P = .037). Time standardization further optimized accuracy, yielding a final mean volume difference of 1.8% ± 0.9%. No statistically significant differences were observed between measurements taken by different technicians (P > .05), demonstrating high interobserver reliability.
iPad-based 3D scanning provides a clinically reliable and cost-effective method of lower limb volumetry. The standardized protocol as described improves scan accuracy and reproducibility. Future studies should evaluate this method in a clinical population to validate its usefulness in disease assessment and progression tracking.
由于缺乏易于获取的临床技术，量化肢体水肿具有挑战性。本研究评估基于iPad的三维（3D）扫描系统用于下肢容积测量的可重复性，并确定影响测量变异性的因素。
使用基于iPad的结构传感器和软件对10名健康志愿者的20条肢体进行扫描。初始扫描遵循制造商的标准说明，但高变异性使数据不适用于临床。为提高准确性，制定了标准化扫描方案，包括解剖校准、扫描距离标准化和扫描时间控制。使用放置在内踝上的3D标记定义254毫米的小腿段，以确保一致的容积测量。扫描距离固定在50至59厘米之间，以减少变焦视差误差，并在下午3点后进行扫描，以尽量减少日间容积波动。多名技术人员对同一肢体进行重复扫描，以评估观察者内和观察者间扫描的可靠性。
实施标准化方案显著降低了测量变异性。定义一致的解剖扫描区域提高了可重复性，平均容积差异从4.7%±3.6%降至2.1%±1.6%。扫描距离标准化减少了与变焦相关的误差，测量一致性从2.6%±1.5%提高到2.0%±1.2%（P = 0.037）。时间标准化进一步优化了准确性，最终平均容积差异为1.8%±0.9%。不同技术人员进行的测量之间未观察到统计学显著差异（P > 0.05），表明观察者间可靠性高。
基于iPad的3D扫描为下肢容积测量提供了一种临床可靠且经济高效的方法。所述标准化方案提高了扫描准确性和可重复性。未来研究应在临床人群中评估该方法，以验证其在疾病评估和进展跟踪中的有用性。
