Abstract: Correlation Between Lymphedema Disease Severity and Lymphoscintigraphic Findings: A Clinical-Radiological Study

Abstract

INTRODUCTION: Lymphoscintigraphy is the gold-standard test for diagnosing lymphedema, and is 96% sensitive for detecting the disease. The major abnormal lymphoscintigraphic findings on the test include delayed transit time to the inguinal or axillary lymph nodes (>1 hour) and dermal backflow. A universal protocol for the test does not exist, our protocol obtains images at 1, 2, and 4 hour intervals to confirm diagnosis of the disease and to achieve a measure of the severity of lymphatic dysfunction (e.g., a patient with a transit time of 4 hours to regional lymph nodes would have worse dysfunction compared to a patient with a transit time of 2 hours). The purpose of this project was to determine if lymphoscintigraphy results correlate with clinical presentation. METHODS: Patients treated in our Lymphedema Program between 2009 and 2017 were reviewed. Diagnosis of lymphedema was determined by history, physical examination, and lymphoscintigraphy. Severity was defined by increased volume of the limb: mild (<20%), moderate (20–40%), severe (>40%). Candidate variables included location (arm, leg), age, duration of symptoms, infection history, and lymphedema type (primary, secondary). An association between lymphedema severity and lymphoscintigraphy findings was determined using the Pearson chi-square test and multivariate logistic regression. RESULTS: One hundred thirty-four patients with 181 affected extremities (24 upper, 157 lower) were included. Clinical severity was: 54% mild, 30% moderate, and 16% severe. Delayed tracer transit to the regional nodes was: 45 minutes (34%), 2 hours (18%), and ≥ 4 hours (48%). Thirty-six percent of extremities demonstrated dermal backflow. Abnormal transit time or dermal backflow was identified in 97% of extremities by 45 minutes and in 3% of limbs by 2 hours. Transit time and dermal backflow were not predictive of clinical severity when adjusting for candidate variables (p > 0.1). CONCLUSION: Clinical severity of lymphedema is not associated with lymphoscintigraphy findings. A lymphoscintigram should be interpreted as normal or abnormal, and does not need to exceed 2 hours.