Evolution of precise and multimodal MRI and TRUS in detection and management of early prostate cancer

Abstract

The combination of T2-weighted MRI with functional MRI, including contrast-enhanced MRI, diffusion-weighted imaging and magnetic resonance spectroscopy, has been recognized as the most promising diagnostic modality for the detection and staging of localized prostate cancer. In spite of the relatively low predictive value of the transrectal ultrasonography (US) image alone, transrectal US-guided prostate biopsy is currently the most clinically used, gold standard technique to confirm pathological prostate cancer. A possible way of improving the precision of prostate biopsy is to use computer-aided analysis, the fusion of the US image with MRI, or by introducing contrast-enhanced US, elastography and/or 3D US to be coupled with computer-assistance or robotic needle placement. Computer-aided surgical navigation systems with image-fusion or image-overlaying capability, integrated with real-time organ tracking systems and/or robotic systems for feedback on the 3D spatial positions of the surgical targets and instruments, can provide attractive opportunities to improve the digitally-coordinated precision of minimally invasive urology, along with predictive ability to guide toward ideal surgical outcomes.

Value of Multiparametric MRI in the Work-up of Prostate Cancer

“…Same patient as in Fig. 1 [41]. This explains why we found that targeting biopsies with "visual" fusion or with the help of a navigation system had similar accuracies [40].…”

Imaging in Prostate Cancer Staging: Present Role and Future Perspectives

“…Accuracy improved when US findings were interpreted in concert with DRE findings and PSA level to estimate the likelihood of extraprostatic extension [17] . However, today, tumors are smaller and extensive extraprostatic spread is uncommon.…”

Image-Fusion for Biopsy, Intervention, and Surgical Navigation in Urology

“…In addition, the potential value of image fusion of Doppler TRUS with MRI in the staging of prostatic cancer was discussed (Selli et al 2007). However, recent attention to image fusion technology for prostate cancer is more toward its value in improving the quality of prostate biopsy by precisely targeting the image-suspicious area, in mapping the 3D localization of biopsy-proven prostate cancer, as well as its value in navigating image-guided focal therapy (Ukimura 2010). Real-time TRUS has been the gold standard of prostate biopsy guidance, and therapeutic intervention, because of the advantages of its real-time nature, its easy-handling, the fact that it is urologist-friendly, its relatively inexpensiveness, and its non-invasiveness.…”

“…Importantly, because the 3-D shapes of the prostate at the time of image-acquisition at preoperative MRI are likely to be different from the intra-operative TRUS images, the precise registration of each 3-D volume data is critical. In order to reduce the potential errors in rigid registration of TRUS with MRI, one solution may include preoperative MR images being obtained while a plastic outer-frame, of exactly the same shape as the real TRUS probe, is placed in the rectum, in order to simulate the deformation of the prostate caused by the absence or presence of a TRUS probe during the acquisition of MR or TRUS images (Ukimura 2010). For another potential solution, Hu and colleagues described a technique using a patient specific model of MR/ TRUS deformation built from simulated data for image-registration (Hu et al 2009).…”

“…However, current ongoing transperineal template 3D mapping biopsy may require 5-mm grid based techniques to detect clinically significant cancer, resulting in a tremendous number of required biopsies, for example, over 100 samples in a large prostate. We are hoping that the improved image-fusion technique of MR and TRUS, and the elastic fusion of 3D real-time TRUS for 3D biopsy mapping techniques , Ukimura 2010 could improve the clinically relevant strategy for prostate biopsy, and also the image-guided management of prostate cancer in the near future.…”