Lesion visualization by targeted computed tomography liver enhancement in dogs.

RATIONALE AND OBJECTIVES

We conducted a pilot study to determine the potential advantages of using liver-specific targeted computed tomography (CT) contrast agents for lesion detection.

METHODS

Eight dogs had liver infarcts created by percutaneous injections of ethanol. Each dog underwent CT scans with four imaging techniques: unenhanced, intravenous contrast enhanced (IVCE), CT arterial portography (CTAP), and targeted liver enhancement with iodipamide ethylester (IDE) particles. Lesions were assessed quantitatively to determine liver-to-lesion density differences and the drop in density across liver edge as a quantitative measure of edge sharpness. Expert readers subjectively analyzed data to determine lesion visibility and edge sharpness.

RESULTS

Liver-to-lesion density differences were greatest with CTAP (56.4 +/- 35.5 Hounsfield units [H]) followed by IDE (41.1 +/- 7.0 H), i.v. (22.7 +/- 6.0 H), and unenhanced scans (13.6 +/- 4.1 H; ps < .05 for CTAP versus unenhanced and IDE versus unenhanced). Edges were best defined both subjectively and quantitatively on IDE-enhanced scans.

CONCLUSION

Targeted liver-specific contrast agents have potential to increase lesion visibility when compared with standard i.v. contrast enhancement of the liver by increasing lesion edge definition and liver-to-lesion attenuation differences. Further work in animal tumor models, and clinical trials as agents become available, appears justified.