Fig 1.
Designated intradermal injection sites in the foot.
Representative photographs of the foot show the locations of indocyanine green injections (green dots). (A) Medial view. (B) Anterior view. (C) Lateral view. (D) Posterior view.
Fig 2.
Examples of region-of-interest (ROI) selection and functional analysis of lymphatic contractility in a lower limb.
(A) Near-infrared fluorescence image of inguinal lymphatic vessels, with four ROIs indicated by pink squares. (B) Example of peak and valley assignment within an ROI (yellow squares), where valleys represent periods without ICG passage and peaks represent periods of ICG transit. (C) Peak–valley intensity plot and scalogram derived from the ROI shown in (B), generated using wavelet-based time–frequency analysis to illustrate contraction frequency and temporal variability.
Fig 3.
Indocyanine green fluorescence lymphography of the lower limb in a cynomolgus monkey.
Lymphatic vessels are shown in a representative image and color-coded according to their regional course at the ankle: anteromedial (blue), posteromedial (yellow), anterolateral (green), and posterolateral (red). High-intensity fluorescence signals correspond to the ICG injection sites in the foot and to the inguinal lymph node (ILN) and popliteal lymph node (PLN).
Fig 4.
Schematic illustration of the four drainage regions in the lower limb.
Anteromedial (blue), posteromedial (yellow), anterolateral (green), and posterolateral (red) regions are shown to define the regional boundaries.
Table 1.
Functional lymphatic contractility metrics in medial and lateral pathways.
Fig 5.
Paired comparison of lymphatic contractility metrics between medial and lateral pathways.
Peak–valley analysis demonstrated significantly higher peak frequency and amplitude in the medial pathway compared with that of the lateral pathway, with no difference in mean intensity. Wavelet-based analysis further revealed higher mean frequency and amplitude in the medial pathway, whereas instantaneous frequency standard deviation did not differ significantly. These regional differences were consistently observed across individual limbs, as visualized in the paired line plots. Each line represents paired data from the same limb. *q < 0.05, **q < 0.01 (Wilcoxon signed-rank test with Benjamini–Hochberg correction).