68Ga-NOTA-Evans Blue TOF PET/MR Lymphoscintigraphy Evaluation of the Severity of Lower Limb Lymphedema.

Abstract

This study was designed to investigate the role of Ga-NOTA-Evans Blue (NEB) time-of-flight (TOF) PET/MR in evaluating lower limb lymphedema by visual analysis and novel parameters. Thirteen patients with unilateral lower limb lymphedema were divided into 3 groups according to the clinical severity: minimal (4 patients), moderate (5 patients), and severe (4 patients). All patients underwent Ga-NEB TOF PET/MR lymphoscintigraphy. The ratio of the standardized uptake value (SUV) of superficial lymphatic vessel (SLV) versus SUV of deep lymphatic vessel (DVL) (SUVslv/dlv) was designed to assess the level of lymphedema severity. The correlation between lymphedema severity and lymphoscintigraphy findings was determined using 1-way analysis of variance, the t test, and Pearson correlation analysis. There was a significant difference in the SUVslv between the affected limbs and normal limbs in all subjects (affected limbs: 0.57 ± 0.32, normal limbs: 1.86 ± 1.43; P < 0.05), which was not found in the SUVdlv (affected limbs: 0.64 ± 0.39, normal limbs: 0.63 ± 0.31; P > 0.1). The SUVslv/dlv of the affected limbs showed statistical differences within the 3 groups (P < 0.05) (minimal group: 1.91 ± 0.45; moderate group: 0.84 ± 0.16; severe group: 0.42 ± 0.11). The statistical analysis revealed a negative correlation between SUVslv/dlv and the severity of lymphedema (r = -0.899; P < 0.01). Ga-NEB TOF PET/MR lymphoscintigraphy can provide anatomical and functional information of lymphatic vessels to guide surgery plans. SUVslv/dlv was well correlated with clinical lymphedema severity and might be potential in evaluating bilateral lower limb lymphedema.