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

Advances in prostate cancer diagnostics in the last decade mean that pre-biopsy multiparametric MRI is now widely accepted as a gold standard, and the approach to performing biopsies has changed drastically. Local anaesthetic (LA) transperineal (TP) techniques have become a focus of research and development. They reduce the incidence of post-biopsy sepsis and lack the need for general anaesthetic, which can aid in reducing the diagnostic timeframe. Many LATP techniques utilize a freehand ultrasound probe, in order to visualize the biopsy needle and target. This requires an experienced operator and distortion of the prostate by the probe may reduce targeting accuracy for cognitive and fusion-based targeting of MRI lesions.

Vector® prostate biopsy intelligently integrates Civco VirtuTRAX Tracking with Medcom Biopsee® MRI fusion software, and Fujifilm Arietta Ultrasound. The combination of these allows for accurate targeting of MRI-identified prostate lesions, with live display of biopsy needle trajectory. Utilising a 2-point entry local anaesthetic transperineal approach, the stable ultrasound probe ensures precision targeting of the MRI/US fused lesions, as well as patient comfort.

The development of Vector® improved the existing accurate fusion BiopSee® software by adding the VirtuTRAX tracked needle, permitting only 2 puncture points to be utilized, thereby, minimizing the trauma and the discomfort for the patient. The technology allows the accurate tracking of the relative position of the probe to the sensor needle. This displays, in millimeters accuracy, the needle position and the distance to the target, thus guiding the clinician to the point at which the sample should be taken. A 3D model permits visualization of the US probe, the tracked needle, the contoured prostate, and the lesions, assisting the user to orientate better to target the suspected lesions.

The experiences of operators have so far been very positive. The skill of fusion can be acquired in a modular approach on a computer in absence of patients. The technical skills to perform the procedure then remain very easy to learn. The accuracy of the real-time needle tracking, displayed on the live fused MRI/US image, is excellent, guiding the operator and indicating when the lesion is correctly aligned in the cross-hair of the needle trajectory.

Patients' feedback has also been positive; the anaesthetic technique, the 2-point perineal access, and stable probe mean this is a very tolerable procedure. There have been minimal post-operative complications and the oncological outcomes have been excellent. We detail our results and experiences in this paper.

Whilst we present relatively early data from the deployment of Vector® in two UK centres, a wider deployment will provide more detail on the reproducibility of our results, as well as the learning curve for clinicians. Increased patient numbers will also allow us to further analyse our data and give more powerful comparisons to established biopsy techniques. Further data is also needed to investigate the possibility of reducing the number of biopsy cores taken in the procedure. We have modeled a saturation target biopsy approach, in which an additional 3-4 cores in the target sector and 3-4 in surrounding areas would be taken. More data is needed in order to validate that the reduced core numbers of target saturation biopsy will maintain high levels of cancer detection. The accuracy of the technology is certainly inviting to such a train of thought.

Our paper describes and demonstrates the Vector® technique to be a promising, safe, and tolerable approach to performing LATP prostate biopsy.

We aim to provide larger multicentre analysis in the future to analyze the viability of the technique.

Written by: Peter Fletcher, Marta De Santis, Simona Ippoliti, Luca Orecchia, Philip Charlesworth, Tristan Barrett, Christof Kastner

Cambridge University Hospitals, Cambridge, UK. Electronic address: ., International Medical School, Tor Vergata University of Rome, Rome, Italy., Hull University Teaching Hospitals, Hull, UK., Fondazione PTV Policlinico, Tor Vergata University Hospital, Rome, Italy., GenesisCare, Cambridge & Windsor, UK., Cambridge University Hospitals, Cambridge, UK; GenesisCare, Cambridge & Windsor, UK., Cambridge University Hospitals, Cambridge, UK; GenesisCare, Cambridge & Windsor, UK. 

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