Simple Frame-based Approach for MR Imaging-guided Abdominal Biopsy: Preliminary Evaluation in a Phantom Model

Although automation offers several benefits in MRI-guided abdominal biopsies, the conventional surgeon-centric approach continues to be the preferred technique. This study presents an ergonomic biopsy device aimed at streamlining the MRI-guided abdominal biopsy process while preserving operator control.

A dedicated belt was designed with adjustable straps to accommodate patients of varying sizes. A biopsy frame with 2 manual degrees of freedom was movably affixed to the belt, allowing for adjustable positioning across the patient's circumference to align with the region of interest. Preliminary testing was performed on an abdominal biopsy phantom with 2 embedded 7-mm tumor mimics in a 3T MRI scanner. Needle guide registration in MRI coordinates was achieved by attaching a water-filled syringe to the guide, which was then navigated to align with each target using a straightforward method involving the acquisition and fusion of parallel images. A clinically relevant half-Fourier acquisition single-shot turbo spin echo sequence was used for both the initial alignment and for intermittent imaging during the stepwise advancement of a metallic clinical needle toward the target.

The device was easy to use, even for a non-experienced operator. The employed methodology enabled straightforward calculation of the 2D path for aligning the syringe with the target. Alignment accuracy was within the submillimeter range. The employed sequence was robust against susceptibility artifacts, enabling precise guidance, with the accuracy of tumor puncture ultimately dependent on the operator.

The proposed biopsy method has the potential to enhance stability and accuracy over traditional techniques, while being more ergonomic and cost-effective than advanced robotic systems, also maintaining human control. Extensive preclinical and clinical evaluation is needed to fully assess effectiveness and safety.