Distribution of Iron Oxide–containing Embosphere Particles after Transcatheter Arterial Embolization in an Animal Model of Liver Cancer: Evaluation with MR Imaging and Implication for Therapy

Abstract

PURPOSE To test whether different-sized iron oxide– containing Embosphere (IOE) particles can be detected by dedicated magnetic resonance (MR) imaging when injected intraarterially in an animal model of liver cancer and whether their distribution could be accurately predicted by MR imaging before confirmation with histopathologic analysis. MATERIALS AND METHODS Twenty New Zealand White rabbits implanted with VX2 liver tumor were randomly assigned to undergo embolization with 100 –300-µm particles (group S; n = 10) or 300 –500-µm particles (group L; n = 10). Embolization was performed with the catheter placed in the proper hepatic artery. T2*-weighted multiplanar MR imaging was performed within 24 hours after the procedure to detect paramagnetic IOE susceptibility artifact. MR imaging interpretation parameters included presence of artifact in the artery and/or at the tumor bed. Hematoxylin and eosin– and Prussian blue–stained pathologic slides were also obtained and the presence of IOE was evaluated similarly. RESULTS The MR detectability rates for IOEs were 100% in both groups. Paramagnetic susceptibility IOE artifact inside the tumor was detected in 30% of group S animals. On pathologic analysis, IOE particles were detected inside the tumor in 70% of this group. IOEs in group L were found outside the tumor within the hepatic artery on MR imaging and histopathologic study (P < .05). CONCLUSIONS MR imaging readily detected IOE particles in an animal model of liver cancer regardless of the particle size. The smaller particles (100 –300 µm) were delivered inside the tumor or in close proximity to the tumor margin, justifying their use for drug delivery or precise embolization.

Predictive factors for complete response of chemoembolization with drug-eluting beads (DEB-TACE) for hepatocellular carcinoma

“…The angiographic end-point of each embolization was not always strictly the same, but weak reproducibility among operators and lack of correlation with perfusion MR as rendered makes it relatively meaningless [38]. In addition, we used different sizes of particles, which may be a confusing factor regarding the suspected better efficacy of smaller ones (100 -300 μm) [4,39,40]. However, it is very difficult to avoid these biases considering the long period of inclusion and the need to treat patients for their own benefit.…”

Multidisciplinary Taiwan Consensus Recommendations for the Use of DEBDOX-TACE in Hepatocellular Carcinoma Treatment

“…Special care should be taken to choose the appropriate bead size in these patients, and Gelfoam embolization to obliterate tumor feeders should be considered. Moreover, larger HCCs may be accompanied by intratumoral arterioportal or arteriovenous shunts, and caution should be taken when using the smaller sizes of embolic particles to avoid hepatic and pulmonary injury [39]. It is recommended that embolization with Gelfoam pledgets be conducted for patients with significant hepatic arterioportal or arteriovenous shunting prior to consideration for DEBDOX-TACE treatment.…”

First Multimodal Embolization Particles Visible on X-ray/Computed Tomography and Magnetic Resonance Imaging

“…18,[22][23][24]30 However, to the best of our knowledge, directly visible particulate embolization particles have never been evaluated in a clinical setting. Furthermore, multimodal-visible particles have not been discussed so far.…”

“…22 Directly visible embolization materials may provide advantages over nonvisible embolization particles for embolization control and therapy follow-up. 18,[22][23][24] Therefore, the motivation of our research was to design a directly visible embolization material by developing a multimodal embolization particle that is visible in more than one imaging modality, namely x-ray/CT and MRI. Its ability to provide image contrast in angiography, CT, and MRI was tested in vitro and in vivo; furthermore, its ability to embolize tissue was demonstrated in an established rabbit tumor embolization model.…”