Lymphedema is a chronic condition marked by swelling in the body’s soft tissues due to impaired or damaged lymphatic function. Lymphedema is estimated to affect about 1 in 1000 in the United States and 1.4 per 1000 based on two European studies. Lymphedema diagnosis relies on clinical visual assessment by physicians, and the quantitative evaluation of lymphatic function is not widely employed due to the lack of standardized and validated metrics. Lymphoscintigraphy is considered the practical gold standard for evaluating lymphedema. With the emergence of advanced surgical therapies, there is a growing demand for quantitative evaluation metrics to objectively evaluate treatment response. To address this unmet need, we reviewed various methods of quantitative lymphoscintigraphy (qLSG) that were used for assessing lymphedema. We found that multiple qLSG approaches have been described. Moreover, the protocols vary widely in terms of tracer type, injection route, dosage, and exercise interventions. We compared the quantitative assessment strategies and highlighted the approaches that may help provide a more objective lymphedema diagnosis and follow-up.

Lymphedema diagnosis is dependent on visual assessment by clinicians. Clinical staging of lymphedema may be complicated by obesity. No quantitative metric is available to measure lymphatic function in patients with both lymphedema and obesity. To address this clinical need, we evaluated nodal uptake percent (NUP) at 120 min in relation to International Society of Lymphology stage and body mass index (BMI). This retrospective study included 20 patients with secondary lower extremity lymphedema, comprising 29 affected and 11 clinically unaffected limbs. NUP was calculated from lymphoscintigraphy. Limb comparisons and receiver operating characteristic (ROC) analyses stratified by BMI were performed. NUP differed among clinically unaffected limbs and ISL stage groups (p = 0.0028). Among patients with BMI < 35 kg/m², NUP was lower in stage 1 (p = 0.0243) and stage 2 (p = 0.0002) limbs than in unaffected limbs. Among those with BMI ≥ 35 kg/m², NUP ranged from reduced to preserved values overlapping the unaffected range. In the lower BMI group, the AUC was 0.9792 (95% CI, 0.9309–1.000). A cutoff < 0.4355% yielded 100% sensitivity and 87.5% specificity. NUP demonstrated its potential to complement clinical staging at BMI < 35 kg/m². However, these findings are hypothesis-generating and require independent external validation.