Fusion of MRI to 3D TRUS for mechanically-assisted targeted prostate biopsy: System design and initial clinical experience

Abstract

This paper presents a mechanically-assisted 3D transrectal ultrasound (TRUS) biopsy system with MRI-3D TRUS fusion. The 3D TRUS system employs a 4 degree-of-freedom linkage for real-time TRUS probe tracking. MRI-TRUS fusion is achieved using a surface-based non-linear registration incorporating thin-plate splines to provide real-time overlays of suspicious MRI lesions on 3D TRUS for intrabiopsy targeted needle guidance. Clinical use of the system is demonstrated on a prospective cohort study of 25 patients with clinical findings concerning for prostate adenocarcinoma (PCa). The MRI-3D TRUS registration accuracy is quantified and compared with alternative algorithms for optimal performance. Results of the clinical study demonstrated a significantly higher rate of positive biopsy cores and a higher Gleason score cancer grading for targeted biopsies using the MRI-3D TRUS fusion as compared to the standard 12-core sextant biopsy distribution. Lesion targeted biopsy cores that were positive for PCa contained a significantly higher percentage of tumor within each biopsy sample compared to the sextant cores and in some patients resulted in identifying higher risk disease. © 2011 Springer-Verlag.