Towards Clinically Useful Quantitative Lymphoscintigraphy: A Scoping Review.

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.