Evaluation of a robotic technique for transrectal MRI-guided prostate biopsies

Abstract

ObjectivesTo evaluate the accuracy and speed of a novel robotic technique as an aid to perform magnetic resonance image (MRI)-guided prostate biopsies on patients with cancer suspicious regions.MethodsA pneumatic controlled MR-compatible manipulator with 5 degrees of freedom was developed in-house to guide biopsies under real-time imaging. From 13 consecutive biopsy procedures, the targeting error, biopsy error and target displacement were calculated to evaluate the accuracy. The time was recorded to evaluate manipulation and procedure time.ResultsThe robotic and manual techniques demonstrated comparable results regarding mean targeting error (5.7 vs 5.8 mm, respectively) and mean target displacement (6.6 vs 6.0 mm, respectively). The mean biopsy error was larger (6.5 vs 4.4 mm) when using the robotic technique, although not significant. Mean procedure and manipulation time were 76 min and 6 min, respectively using the robotic technique and 61 and 8 min with the manual technique.ConclusionsAlthough comparable results regarding accuracy and speed were found, the extended technical effort of the robotic technique make the manual technique – currently – more suitable to perform MRI-guided biopsies. Furthermore, this study provided a better insight in displacement of the target during in vivo biopsy procedures.

A preliminary evaluation of a flexible needle steering algorithm using magnetic resonance images as feedback

“…Nevertheless, the time spent in a complete needle insertion in this work is, on avarege, 19 minutes less than the time of a manual MR-guided prostate biopsy using a rigid needle. The average procedure time for an MR-guided prostate biopsy reported by Schouten et al [7] is 61 minutes, while in our study is 42 minutes.…”

“…These systems are built with MR-compatible materials and the needle is driven by pneumatic or piezoelectric actuators. Semi-automated systems have been designed to robotically position the needle guide, allowing a manual needle insertion in the direction of the target [6], [7], [8]. Manual insertions are performed using thick and rigid needles while assuming that they follow a straight path.…”

In-bore MRI interventions

“…Much of this increased time is from repeatedly moving the patient out of the scanner to enable access to the needle, followed by repeat imaging. Some investigators have therefore looked at MR compatible robotic devices via rectal [32], gluteal [33] and perineal approaches [ 35,36] recently described an MR compatible mechatronic system for transperineal needle guidance ( Fig. 1).…”

Magnetic Resonance Imaging-Guided Prostate Biopsy: Institutional Analysis and Systematic Review

“…In patients in whom no coil was used, the rectum was filled with ultrasonic gel to avoid artifacts. The MRI protocol consists of a high-resolution T2w sequence in all three dimensions, axial diffusion-weighted imaging (DWI) with b-values of 0, 100, 400, and 800 sec/mm 2 , a contrast-enhanced 3D-T1-weighted sequence before and after the application of a standard dose of Gd-DOTA (Dotarem ® , Guerbet, France) (dynamic contrast-enhanced imaging -DCE-MRI), and MR spectroscopy [5,11,16]. Two radiologists (T. H.H, P.…”

“…The advantage of a robotic device is that the patient does not have to be moved in and out of the MRI scanner during the biopsy session, which decreases the procedure time, enhances patient comfort, and improves needle positioning [26]. The examination methods used for robotic-assisted biopsies are transgluteal and transrectal, and the intervention time for these methods ranges between 39 min and 76 min [16,28,34]. A limitation of our study that should be reported is the inconsistent imaging protocol for the MRI examinations prior to biopsy.…”