title: Sensitivity and specificity of fluorescence microlymphography for detecting lymphedema of the lower extremity.
abstract: Fluorescence microlymphography (FML) is used to visualize the lymphatic capillaries. A maximum spread of the fluorescence dye of ≥ 12 mm has been suggested for the diagnosis of lymphedema. However, data on sensitivity and specificity are lacking. The aim of this study was to investigate the accuracy of FML for diagnosing lymphedema in patients with leg swelling. Patients with lower extremity swelling were clinically assessed and separated into lymphedema and non-lymphatic edema groups. FML was studied in all affected legs and the maximum spread of lymphatic capillaries was measured. Test accuracy and receiver operator characteristic (ROC) analysis was performed to assess possible threshold values that predict lymphedema. Between March 2008 and August 2011 a total of 171 patients (184 legs) with a median age of 43.5 (IQR 24, 54) years were assessed. Of those, 94 (51.1%) legs were diagnosed with lymphedema. The sensitivity, specificity, positive and negative likelihood ratio and positive and negative predictive value were 87%, 64%, 2.45, 0.20, 72% and 83% for the 12-mm cut-off level and 79%, 83%, 4.72, 0.26, 83% and 79% for the 14-mm cut-off level, respectively. The area under the ROC curve was 0.82 (95% CI: 0.76, 0.88). Sensitivity was higher in the secondary versus primary lymphedema (95.0% vs 74.3%, p = 0.045). No major adverse events were observed. In conclusion, FML is a simple and safe technique for detecting lymphedema in patients with leg swelling. A cut-off level of ≥ 14-mm maximum spread has a high sensitivity and high specificity of detecting lymphedema and should be chosen.
authors.affiliation: Swiss Cardiovascular Center, Division of Angiology, Inselspital, University Hospital and University of Bern, Switzerland. keoxx006@umn.edu
authors.forename: Hong H
authors.initials: HH
authors.lastname: Keo
authors.forename: Marianne
authors.initials: M
authors.lastname: Schilling
authors.forename: Roland
authors.initials: R
authors.lastname: Büchel
authors.forename: Ernst
authors.initials: E
authors.lastname: Gröchenig
authors.forename: Rolf P
authors.initials: RP
authors.lastname: Engelberger
authors.forename: Torsten
authors.initials: T
authors.lastname: Willenberg
authors.forename: Iris
authors.initials: I
authors.lastname: Baumgartner
authors.forename: Silvia B
authors.initials: SB
authors.lastname: Gretener
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007866:Leg / Q000601:surgery*; D035002:Lower Extremity / Q000473:pathology / Q000601:surgery*; D042601:Lymphatic Vessels / Q000601:surgery*; D008209:Lymphedema / Q000601:surgery*; D008220:Lymphography / Q000379:methods; D008297:Male; D008875:Middle Aged; D061848:Optical Imaging / Q000379:methods
keywords: edema; fluorescence dyes; leg; lymphedema; microscopy fluorescence