INDIRECT COMPUTED-TOMOGRAPHY LYMPHOGRAPHY USING IODINATED NANOPARTICLES - TIME AND DOSE-RESPONSE IN NORMAL CANINE LYMPH-NODES

Rationale and Objectives. We evaluated the effect of time and dose on lymph node iodine uptake after subcutaneous or submucosal administration of iodinated nanoparticles used for computed tomography lymphography. Methods. We injected 0.1-6 ml of a 15% wt/vol iodinated nanoparticle suspension into the distal extremities subcutaneously (n = 5) or into the buccal submucosa (n = 7) of normal dogs. Precontrast and 4, 12, 24, and 48 hr after contrast administration, CT scans of opacified lymph nodes were obtained. Iodine concentration, node volume, and total iodine uptake were estimated for each node. Results. All estimated parameters increased between 4 and 12 hr postcontrast (p <.05), with no significant increase thereafter. At 24 hr postcontrast, iodine concentration ranged from 0.01 to 16.1 mg/ml (47-568 Hounsfield units). The average iodine concentration and total iodine uptake increased with contrast dose (p <.05) for all lymph node groups evaluated. Node opacification also revealed internal architectural detail. Conclusion. Subcutaneous and submucosal injections of iodinated nanoparticles result in a dose-dependent iodine uptake in targeted lymph nodes. In addition, architectural detail within opacified nodes can be visualized.