Anthropomorphic liver phantom with flow for multimodal image-guided liver therapy research and training

Abstract

PurposeThe objective of this study was to develop a multimodal, permanent liver phantom displaying functional vasculature and common pathologies, for teaching, training and equipment development in laparoscopic ultrasound and navigation.MethodsMolten wax was injected simultaneously into the portal and hepatic veins of a human liver. Upon solidification of the wax, the surrounding liver tissue was dissolved, leaving a cast of the vessels. A connection was established between the two vascular trees by manually manipulating the wax. The cast was placed, along with different multimodal tumor models, in a liver shaped mold, which was subsequently filled with a polymer. After curing, the wax was melted and flushed out of the model, thereby establishing a system of interconnected channels, replicating the major vasculature of the original liver. Thus, a liquid can be circulated through the model in a way that closely mimics the natural blood flow.ResultsBoth the tumor models, i.e., the metastatic tumors, hepatocellular carcinoma and benign cyst, and the vessels inside the liver model, were clearly visualized by all the three imaging modalities: CT, MR and ultrasound. Doppler ultrasound images of the vessels proved the blood flow functionality of the phantom.ConclusionBy a two-step casting procedure, we produced a multimodal liver phantom, with open vascular channels, and tumor models, that is the next best thing to practicing imaging and guidance procedures in animals or humans. The technique is in principle applicable to any organ of the body.

Dynamic Hepatocellular Carcinoma Model Within a Liver Phantom for Multimodality Imaging

“…Multimodal liver phantoms were applied in a number of different previous studies [ 24 , 27 , 33 , 45 ]. Among these studies, only two phantoms presented by Rethy et al [ 31 ] and Chmarra et al [ 24 ] allow the combination of CT, ultrasound, and MRI modalities. Bazrafshan et al [ 46 ] also prepared a liver-mimicking MRI gel phantom.…”

“…Most of the liver phantoms were developed for applications in CT imaging [ [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] ], while far less phantoms were intended for MRI [ [24] , [25] , [26] ] and ultrasound [ [27] , [28] , [29] , [30] ]. However, multimodal liver phantoms which can be applied under different medical imaging modalities including MRI, CT, and ultrasound are still less developed [ 12 , 24 , 31 ].…”

“…There are quite a number of liver phantoms proposed and described in the scientific literature or available in the market which describes the blood vessel structures, model tumors [ 24 , 27 , 31 ], and provide blood flow functionality [ 31 ]. However, none of them provideflow functionality through tumors like HCC.…”

“…The most common substances used for liver phantom fabrication are polyacrylamide (PAA), carrageenan, polysaccharide, agar, agarose [24,27], polyvinyl alcohol (PVA) [32], polyurethane [31], gelatin [33,34] and silicone, commercial rigid plastics [35], and elastomeric (rubber-like) materials [36].…”

Designing and validating a PVA liver phantom with respiratory motion for needle-based interventions

“…Other research mimicked the anthropomorphic shape of the liver. For example, Rethy et al [12] developed a multimodal permanent liver phantom displaying functional vasculature and pathologies, by wax and silicone molding of a donated human liver. In addition, Efthymios et al [13] presented anatomically realistic ultrasound phantoms based on patient scans, by pouring gel wax in 3D-printed molds.…”