A low cost training model for MRI-Ultrasound fusion guided biopsy

Purpose: Ultrasonography (US)-guided biopsy may be used for the diagnosis of a wide variety of other bladder and pelvic suspicious lesions, however magnetic resonance imaging (MRI)-US fusion combines the superior diagnostic accuracy of MRI for detecting suspicious lesions with the cost effectiveness and familiarity of US biopsy. To the best of our knowledge to date there is no model for training operators in MRI-US fusion guided biopsies. The aim of this study is to report on a model for fusion guided biopsies including an MRI visible phantom that is invisible on US.

Methods: A regular matrix for image phantoms is made from agarose gel (3% to 5%). Three phantom mediums were created (with Copper sulphate, Ferric hydroxide and medical mineral mud). After cooling and consolidating, these phantom mediums were cut to 0.5 cm cubes. An agar gel of 2 – 5% gives US and MRI representations that are equally artifact-free. A house hold plastic container was filled with a 2 – 3 cm layer of agar gel. Some phantom particles were placed on the agar gel and then covered with an additional 2 – 3 cm layer of agar gel (figure).

Fig. 1: Training model for MRI-US fusion guided biopsy

Results: The MRI-US fusion images were able to identify and localize the phantom particles. While the agar particles including Ferric hydroxide and medical mineral mud were visible by both MRI and US, the Copper sulphate agar particles were visible only by MRI.

Conclusions: We were able to create a low cost, home-made training model for MRI-US fusion guided biopsy.