Constructing and Pilot Testing a Novel Prostate Magnetic Resonance Imaging/Ultrasound Fusion Biopsy Phantom.

OBJECTIVE

To describe the design and build of a novel phantom for magnetic resonance imaging (MRI)/ultrasound (US) fusion biopsy and present pilot testing results from a multicenter urology resident training session.

METHODS

We cast our phantom from polyvinylchloride-plastisol that features 10 mm and 5 mm blue clay tumors, a urethral lumen, and an echogenic capsule. T2-weighted images were acquired with a 3T MR750 scanner (GE Healthcare, Boston, MA). Fusion testing was performed on the bkFusion system (BK ultrasound, Peabody, MA) with MIM Symphony software (MIM, Cleveland, OH) and an 18-gauge Bard Monopty disposable gun (Bard, Murray Hill, NJ). Twenty residents from 6 urology programs in Chicago performed proctored user testing.

RESULTS

The per phantom material cost was $12. The phantom was compatible with all necessary equipment to create a MRI/US fusion data set. MRI and US imaging characteristics were excellent with hypointense lesions. Image fusion was achieved through both end and side fire ultrasound probes. The phantom allowed for biopsies to be performed, and target lesion hits were confirmed by visual inspection of core samples. 38% (8/21) of urology resident pilot testing participants had previously performed a fusion biopsy. The mean postsession survey scores were (1-10 [best]): realism 9.0, usefulness 9.4, ease of use 9.1, ease of orientation 8.9, and overall experience 9.3.

CONCLUSION

This simple and inexpensive phantom allows for training and accuracy testing of MRI/US fusion biopsy hardware and software platforms.