Assessment of lymphedema with lymphoscintigraphy: Can nodal quantification help?

Lymphoscintigraphy with combined qualitative and quantitative analysis is reported to be a more sensitive approach to diagnose lymphedema in comparison with the conventional clinical analysis. Our study seeks to evaluate the diagnostic performance of lower limb lymphoscintigraphy with amalgamation of qualitative and quantitative analysis by measuring the ilio-inguinal nodal uptake. This prospective observational study was comprised of 86 patients (172 limbs) diagnosed with lower limb lymphedema. After a thorough clinical grading of edema, radionuclide lymphoscintigraphy was performed as per a dedicated institutional protocol. Ilio-inguinal nodal quantification of tracer uptake was computed along with the visual study of the scans. Additionally, the corresponding mean nodal uptake percentage for each grade of lymphedema was assessed and a cut off nodal uptake percentage to differentiate between normal and abnormal limbs was defined. Although quantitative analysis with nodal uptake percentage provides objective criteria to diagnose lymphedema, it can only act as an adjunct to qualitative method without replacing it. Finally, standardization of procedure for quantitative lymphoscintigraphy is needed including the potential for combining both rate of clearance of tracer from injection site and nodal uptake for quantification.