Vector Prostate Biopsy: A Novel Magnetic Resonance Imaging/Ultrasound Image Fusion Transperineal Biopsy Technique Using Electromagnetic Needle Tracking Under Local Anaesthesia

Abstract

Background: Prostate magnetic resonance imaging (MRI) is now standard for assessment of suspected prostate cancer (PCa). A variety of approaches to MRI-based targeting has revolutionised prostate biopsies.

Objective: To describe the procedure and show the accuracy and tolerability of a novel Vector MRI/ultrasound fusion transperineal (TP) biopsy technique that uses electromagnetic (EM) needle tracking under local anaesthesia (LA).

Design, setting, and participants: Vector prostate biopsy using BiopSee fusion software, EM tracking technology, and transrectal ultrasound was performed in 69 patients meeting the biopsy criteria in two UK centres between September 2020 and August 2022.

Surgical procedure: Stepper-mounted rectal ultrasound images were fused with MRI scans. LA was applied into two defined perineal tracks and a needle sheath with an EM sensor was inserted. The biopsy needle was directed precisely through the sheath to MRI targets under EM tracking. Biopsies were taken without antibiotic prophylaxis.

Measurements: Cancer detection (any PCa; grade group ≥2), side effects, and patient experience measures were recorded.

Results and limitations: Cancer detection in patients with Likert 4-5 lesions was 98% for any PCa and 83% for grade group ≥2. According to the 50 questionnaires returned, 42 patients (84%) reported no or minimal pain, while 40 (80%) reported no or minimal discomfort. No episodes of postoperative urinary retention occurred, and only one patient required treatment for infection. Limitations include the low patient number and incomplete responses to questionnaires.

Conclusions: This novel Vector technique provides a feasible and tolerable procedure for MRI/ultrasound fusion TP biopsy under LA, with high cancer detection rates. This is achieved while maintaining patient comfort and with minimal rates of complications.

Patient summary: We report a novel technique that uses electromagnetic needle tracking to perform highly accurate and comfortable prostate biopsies through the perineum under local anaesthetic.

Keywords: Biopsy; Electromagnetic needle tracking; Fusion; Local anaesthetic; Magnetic resonance imaging; Prostate cancer; Transperineal; Ultrasound; Vector.