Interstitial Digital Subtraction Pedal Lymphangiography with an Ionic Contrast Agent: A Porcine Pilot Study

Background Although US-guided intranodal lymphangiography has enabled targeted visualization and intervention for lymphatic leaks, current interstitial approaches, such as MR lymphangiography, have substantial drawbacks. A simpler technique for pedal lymphangiography is required. Purpose To evaluate the feasibility, safety, and image quality of rapid interstitial digital subtraction lymphangiography (DSLA) involving intradermal injection of iodinated contrast media in a porcine model. Materials and Methods This animal study received institutional approval. Interstitial DSLA was performed on 10 healthy female large white pigs (mean weight, 50.1 kg ± 7.0 [SD]). Using a custom manifold and 25-gauge needles, 6 mL of iodinated contrast agent was injected intradermally across three interdigital web spaces per hind limb (0.1 mL/sec per site). Dynamic DSLA (2-6 frames per second) and subsequent spot radiography were performed. Technical success, image quality (three-point scale: good, fair, or poor), time to superficial inguinal lymph node visualization, contrast agent washout time, and adverse events (3-day follow-up) were assessed. A general linear mixed model with random animal effects was used to compare superficial inguinal lymph node visualization time between limbs. Interreader agreement for image quality was assessed with the weighted κ. Results Lymphatic visualization was technically successful in 97% (29 of 30) of limbs. Among successful examinations (n = 29), image quality was good in 52% (15 of 29), fair in 38% (11 of 29), and poor in 10% (three of 29) of limbs. The interreader agreement of imaging quality was excellent (κ = 0.95). The model-based overall mean superficial inguinal lymph node visualization time was 75 seconds, with no evidence of a difference between limbs (P = .91). The mean contrast agent washout time (measured in 14 limbs) was 33.8 minutes ± 12.0. No venous opacification or major adverse events occurred; minor injection site edema resolved spontaneously. Conclusion Interstitial DSLA performed with intradermal injection of iodinated contrast media was feasible, rapid, and safe for high-spatial-resolution peripheral lymphatic imaging in a porcine model. © The Author(s) 2026. Published by the Radiological Society of North America under a CC BY 4.0 license. Supplemental material is available for this article.