TRUS–MRI image registration: a paradigm shift in the diagnosis of significant prostate cancer

Abstract

Accuracy of multiparametric MRI has greatly improved the ability of localizing tumor foci of prostate cancer. This property can be used to perform a TRUS-MR image registration, new technological advance, which allows for an overlay of an MRI onto a TRUS image to target a prostate biopsy toward a suspicious area Three types of registration have been developed: cognitive-based, sensor-based, and organ-based registration. Cognitive registration consists of aiming a suspicious area during biopsy with the knowledge of the lesion location identified on multiparametric MRI. Sensor-based registration consists of tracking in real time the TRUS probe with a magnetic device, achieving a global positioning system which overlays in real-time prostate image on both modalities. Its main limitation is that it does not take into account prostate and patient motion during biopsy. Two systems (Artemis and Uronav) have been developed to partially circumvent this drawback. Organ-based registration (Koelis) does not aim to track the TRUS probe, but the prostate itself to compute in a 3D acquisition the TRUS prostate shape, allowing for a registration with the corresponding 3D MRI shape. This system is not limited by prostate/patient motion and allows for a deformation of the organ during registration. Pros and cons of each technique and the rationale for a targeted biopsy only policy are discussed.

Evaluation of the ‘Prostate Interdisciplinary Communication and Mapping Algorithm for Biopsy and Pathology’ (PIC-MABP)

“…These failures have to be corrected cognitively by the examiner, who therefore needs high understanding of anatomical situation and movements. To eliminate these limitations, non-rigid and organ-based registration methods of mpMRI and TRUS have been developed recently [20,21]. These methods try to track the prostatic gland itself and use 3D computing software to align and co-register the whole prostatic volume instead of rigid anatomical structures.…”

Magnetic Resonance Imaging–Transectal Ultrasound Image-fusion Biopsies Accurately Characterize the Index Tumor: Correlation with Step-sectioned Radical Prostatectomy Specimens in 135 Patients

“…Our 95% accuracy in identifying the location of the index lesion could enhance clinical decisionmaking. Ongoing advances in precise localization of biopsy trajectories in the 3D space of the prostate will facilitate mapping of biopsy-proven cancer [10,24]. Even if biopsyproven cancer is invisible in imaging (identified by a random biopsy, RB), technology for tracking the RB trajectory using real-time 3D TRUS (Urostation) can localize the 3D location of RB-proven cancer [10,13,18].…”

Hybrid 2D–3D ultrasound registration for navigated prostate biopsy

“…The improvements in mean TRE is statistically significant. Considering that clinically significant tumor are above 0.5 cc (equivalent to a sphere of radius 5 mm) [13], TRE under 5mm is clinically acceptable and relevant. 74.8% of overall TRE are under 5mm.…”