Eugene R. Cooper

Nanoparticulate computed tomography contrast agents for blood pool and liver-spleen imaging.

RATIONALE AND OBJECTIVESnWe investigated the properties of a group of iodine-containing, insoluble compounds formulated as nanoparticles for use as potential blood pool and liver-spleen contrast agents.nnnMETHODSnHigh-resolution, quantitative computed tomography (CT) was performed prior to and at intervals following the intravenous administration of the contrast agents to rabbits. Time-density characteristics for three organs were evaluated.nnnRESULTSnExcellent enhancement of blood (< or = 232 Hounsfield units [HU]), liver (< or = 263 HU), and spleen (< or = 350 HU) was achieved at the administered dose of 3.0 ml/kg. The composition of the agents influenced the biodistribution, as well as the residence time in blood, and time to peak enhancement in liver.nnnCONCLUSIONnIodinated nanoparticulate compounds are promising CT contrast agents. Development of agents with desirable pharmacokinetic and biodistribution profiles may permit application-specific contrast enhancement.

Percutaneous computed tomography lymphography in the rabbit by subcutaneously injected nanoparticulates.

RATIONALE AND OBJECTIVESnSurgical lymphangiography is infrequently used in staging cancer because of its inherent limitations. Radiopaque nanoparticulates target lymph nodes draining interstitial tissues and could make percutaneous lymphography feasible.nnnMETHODSnExperimental nanoparticulate contrast agent formulations were injected subcutaneously in the forepaw or hindpaw of normal rabbits or rabbits with induced reactive nodal hyperplasia. Axillary and popliteal nodes were imaged with thin-section computed tomography (CT) using quantitative methods to measure node enhancement. Dose-response (0.1-2.0 ml) and time course (4 hr to 10 weeks) of enhancement were assessed.nnnRESULTSnNodal enhancement above 100 Hounsfield units was consistently obtained. Enhancement was significantly related to dose and peaked at 10 hr with slow washout over the observation period. Nodes with reactive hyperplasia were larger and had heterogeneous enhancement patterns distinctly different from normal nodes.nnnCONCLUSIONnPercutaneous CT lymphography effectively depicts the macroscopic intranodal architecture in rabbits.

Nanocrystalline Computed Tomography Contrast Agents for Blood-pool and Liver-spleen Imaging

Gazelle GS, Wolf GL, Bacon ER, Mclntire GL, Cooper ER, Toner JL. Nanocrystalline computed tomography contrast agents for blood-pool and liver-spleen imaging. Invest Radiol 1994;29:S286–S288.