Evaluation of Hepatic Injury and Regeneration After Lipiodol-Only Embolization in Normal Rabbit Liver Using 3T Dynamic-Enhanced MRI and Histopathology

Trans-arterial embolization (TAE) selectively embolizes the hepatic artery to block liver perfusion and is widely used for the treatment of hepatic tumors, traumatic hemorrhage, and vascular malformations. The aim of this study was to evaluate the early hepatic effects of lipiodol-only embolization at partial stasis, independent of additional embolic or chemotherapeutic agents in a rabbit model using imaging and histological examination. Nineteen New Zealand female rabbits were used; six were assigned to a pilot study for imaging protocol validation. Of the remaining 13 rabbits, three received normal saline (control), while 10 underwent lipiodol treatment (Group L) via the proper hepatic artery to evaluate hepatic changes. Computed tomography (CT), conventional magnetic resonance imaging (MRI), gadoxetate-enhanced MRI, and dynamic contrast-enhanced MRI (DCE-MRI) were performed before, immediately after, and 24-h post-embolization. In the Group L, unlike conventional MRI, gadoxetate-enhanced MRI demonstrated a significant decrease (P<0.05) in signal intensity immediately and 24-h post-embolization. On DCE-MRI, K_trans, iAUC₆₀, CER, Max. slope, PEI and TTP showed significant differences between pre-and immediately post-embolization and between immediate and 24-h post-embolization (P<0.05, Wilcoxon signed-rank test), but not between pre-and 24-h post-embolization. Histologically, the median total Suzuki score was higher (P<0.05) in Group L [5 (4–6)] than in controls [0 (0–1)]. The Ki-67 proliferation index was also higher in Group L [23.61 (17.14–27.54)] than in controls [2.14 (1.78–3.26)] (P<0.05). Based on DCE-MRI and histopathologic findings, clinically relevant lipiodol dose (0.1mL/kg) induced transient hepatic injury and perfusion changes in normal liver, with partial recovery by 24h. DCE-MRI was most sensitive in detecting these dynamic changes, suggesting that DCE-MRI may serve as a non-invasive imaging marker for assessing hepatic injury and recovery following embolization.