Iodinated Nanoparticles for Indirect Computed Tomography Lymphography of the Craniocervical and Thoracic Lymph Nodes in Normal Dogs

Rationale and Objectives. We evaluated the imaging characteristics of an interstitially or intraperitoneally delivered iodinated particulate contrast agent for computed tomography (CT) lymphography of the craniocervical and thoracic lymph nodes. Methods. We injected 2–4 ml of 15% wt/vol iodinated nanoparticle suspension subcutaneously, submucosally, or intraperitoneally in eight normal dogs. CT and plain radiographic images were obtained prior to contrast administration and 4 hr, 24 hr, and 7 days after injection. Correlation was made to detailed postmortem assessment. Results. CT images showed enhancement of regional nodes draining injection sites. Mean attenuation of opacified nodes was 313 ± 297 (mean ± standard deviation), 536 ± 453, and 492 ± 372 Hounsfield units at 4 hr, 24 hr, and 7 days postinjection, respectively. Lymph node opacification on CT images correlated well with node location found at postmortem. Conclusion. Craniocervical and thoracic lymph nodes can be effectively opacified from interstitial or intraperitoneal delivery of this iodinated nanoparticulate contrast agent.