Medical image computing and computer-aided medical interventions applied to soft tissues. Work in progress in urology

Until recently, Computer-Aided Medical Interventions (CAMI) and Medical Robotics have focused on rigid and non deformable anatomical structures. Nowadays, special attention is paid to soft tissues, raising complex issues due to their mobility and deformation. Mini-invasive digestive surgery was probably one of the first fields where soft tissues were handled through the development of simulators, tracking of anatomical structures and specific assistance robots. However, other clinical domains, for instance urology, are concerned. Indeed, laparoscopic surgery, new tumour destruction techniques (e.g. HIFU, radiofrequency, or cryoablation), increasingly early detection of cancer, and use of interventional and diagnostic imaging modalities, recently opened new challenges to the urologist and scientists involved in CAMI. This resulted in the last five years in a very significant increase of research and developments of computer-aided urology systems. In this paper, we propose a description of the main problems related to computer-aided diagnostic and therapy of soft tissues and give a survey of the different types of assistance offered to the urologist: robotization, image fusion, surgical navigation. Both research projects and operational industrial systems are discussed

Thermal dosimetry for bladder hyperthermia treatment. An overview.

The urinary bladder is a fluid-filled organ. This makes, on the one hand, the internal surface of the bladder wall relatively easy to heat and ensures in most cases a relatively homogeneous temperature distribution; on the other hand the variable volume, organ motion, and moving fluid cause artefacts for most non-invasive thermometry methods, and require additional efforts in planning accurate thermal treatment of bladder cancer. We give an overview of the thermometry methods currently used and investigated for hyperthermia treatments of bladder cancer, and discuss their advantages and disadvantages within the context of the specific disease (muscle-invasive or non-muscle-invasive bladder cancer) and the heating technique used. The role of treatment simulation to determine the thermal dose delivered is also discussed. Generally speaking, invasive measurement methods are more accurate than non-invasive methods, but provide more limited spatial information; therefore, a combination of both is desirable, preferably supplemented by simulations. Current efforts at research and clinical centres continue to improve non-invasive thermometry methods and the reliability of treatment planning and control software. Due to the challenges in measuring temperature across the non-stationary bladder wall and surrounding tissues, more research is needed to increase our knowledge about the penetration depth and typical heating pattern of the various hyperthermia devices, in order to further improve treatments. The ability to better determine the delivered thermal dose will enable clinicians to investigate the optimal treatment parameters, and consequentially, to give better controlled, thus even more reliable and effective, thermal treatments

Minimally invasive photoacoustic imaging:Current status and future perspectives

Photoacoustic imaging (PAI) is an emerging biomedical imaging modality that is based on optical absorption contrast, capable of revealing distinct spectroscopic signatures of tissue at high spatial resolution and large imaging depths. However, clinical applications of conventional non-invasive PAI systems have been restricted to examinations of tissues at depths less than a few cm due to strong light attenuation. Minimally invasive photoacoustic imaging (miPAI) has greatly extended the landscape of PAI by delivering excitation light within tissue through miniature fibre-optic probes. In the past decade, various miPAI systems have been developed with demonstrated applicability in several clinical fields. In this article, we present an overview of the current status of miPAI and our thoughts on future perspectives.status: publishe

Review of photoacoustic imaging plus X

Photoacoustic imaging (PAI) is a novel modality in biomedical imaging technology that combines the rich optical contrast with the deep penetration of ultrasound. To date, PAI technology has found applications in various biomedical fields. In this review, we present an overview of the emerging research frontiers on PAI plus other advanced technologies, named as PAI plus X, which includes but not limited to PAI plus treatment, PAI plus new circuits design, PAI plus accurate positioning system, PAI plus fast scanning systems, PAI plus novel ultrasound sensors, PAI plus advanced laser sources, PAI plus deep learning, and PAI plus other imaging modalities. We will discuss each technology's current state, technical advantages, and prospects for application, reported mostly in recent three years. Lastly, we discuss and summarize the challenges and potential future work in PAI plus X area

Robot-assisted Optical Ultrasound Scanning

Optical ultrasound, where ultrasound is both generated and received using light, can be integrated in very small diameter instruments making it ideally suited to minimally invasive interventions. One-dimensional information can be obtained using a single pair of optical fibres comprising of a source and detector but this can be difficult to interpret clinically. In this paper, we present a robotic-assisted scanning solution where a concentric tube robot manipulates an optical ultrasound probe along a consistent trajectory. A torque coil is utilised as a buffer between the curved nitinol tube and the probe to prevent torsion on the probe and maintain the axial orientation of the probe while the tube is rotating. The design and control of the scanning mechanism are presented along with the integration of the mechanism with a fibre-based imaging probe. Trajectory repeatability is assessed using electromagnetic tracking and a technique to calibrate the transformation between imaging and robot coordinates using a known model is presented. Finally, we show example images of 3D printed phantoms generated by collecting multiple OpUS A-scans within the same 3D scene to illustrate how robot-assisted scanning can expand the field of view

Image-guided prostate biopsy robots: A review

At present, the incidence of prostate cancer (PCa) in men is increasing year by year. So, the early diagnosis of PCa is of great significance. Transrectal ultrasonography (TRUS)-guided biopsy is a common method for diagnosing PCa. The biopsy process is performed manually by urologists but the diagnostic rate is only 20%–30% and its reliability and accuracy can no longer meet clinical needs. The image-guided prostate biopsy robot has the advantages of a high degree of automation, does not rely on the skills and experience of operators, reduces the work intensity and operation time of urologists and so on. Capable of delivering biopsy needles to pre-defined biopsy locations with minimal needle placement errors, it makes up for the shortcomings of traditional free-hand biopsy and improves the reliability and accuracy of biopsy. The integration of medical imaging technology and the robotic system is an important means for accurate tumor location, biopsy puncture path planning and visualization. This paper mainly reviews image-guided prostate biopsy robots. According to the existing literature, guidance modalities are divided into magnetic resonance imaging (MRI), ultrasound (US) and fusion image. First, the robot structure research by different guided methods is the main line and the actuators and material research of these guided modalities is the auxiliary line to introduce and compare. Second, the robot image-guided localization technology is discussed. Finally, the image-guided prostate biopsy robot is summarized and suggestions for future development are provided

Comparison of The Functional and Oncological Outcomes of the Sub-trigonal Versus Conventional Robotic Radical Prostatectomy for Prostate Cancer

6.1. Background The subtrigonal approach for robotic assisted radical prostatectomy was first described in 2010 as the most anatomically preserving technique, in which the prostate can be completely removed through the Douglas pouch. This technique was introduced in the Urology Department of Tuebingen University Hospital in June 2013 after many years of performing the conventional transperitoneal robotic prostatectomy, however few data is available regarding its outcome. 6.2. Objectives The aim of this study is to compare the functional and oncological outcomes of subtrigonal approach versus the conventional approach for robotic radical prostatctomy 6.3. Methods Consecutive groups of patients who underwent TPRP (n=126) from 01/2012 to 05/2013, and those who switched and underwent STRP (n=62) from 01/2014 to 01/2015 were compared;. Functional outcomes were evaluated using ICIQ and IIEF of both groups by questionnaire and telephone protocols. Oncological outcomes were assessed regarding positive surgical margins and biochemical recurrence free survival (PSA ≥ 0.02 ng/ml) using the Kaplan Meier curve. Postoperative complications were classified using the Clavien-Dindo system. Statistical analysis was performed using the jmp v.12 software®. Mann-Whitney-U and Pearson x2 tests were employed to compare the continuous and categorical variables, respectively. The Kaplan Meier curve was applied to present the survival data 6.4. Results The median age and follow-up time in the TPRP and STRP groups were 64 and 62.5 years and 34 and nine months, respectively. Within 7 days of catheter removal, 37/93 patients (40%) in group A were continent compared to 23/53 (43%) in group B (p-value = 0.67). At 3, 6 and 12-month intervals, the continence recovery rates were 71%, 73% and 87% in group A versus 76%, 89% and 96% in group B. The p-values were 0.55, 0.02 and 0.054, respectively. 15 and 7 patients in group A and B, respectively, underwent bilateral nerve sparing surgery (NS). In group A, 2/15 (13%) could achieve enough erection for penetration versus 3/7 (43%) in group B; (p-value = 0.13). The overall positive surgical margin (PSM) rate was 16% in group A versus 8% in group B (p-value = 0.11). According to the pathological stage, PSM rates in pT2, pT3a and pT3b were 7.2%, 53% and 55.6% in group A compared to 2.2%, 11% and 60% in group B, respectively (p-values = 0.19, 0.03 and 0.87). PSM in pT3a was significantly lower in group B. When comparing the PSM rate at the prostatic apex, it was 9.8% in group A versus 1.6% in group B; with a significant difference (p-value = 0.02). The BCR 1y-free survival was 91% in group A versus 94% in group B (Log-rank p-value = 0.57). 6.5. Conclusion The anatomical preservative sub-trigonal approach for RARP increases the post-operative continence recoverability. Our results approved the oncological safety of this technique even in locally advanced cases. Sub-trigonal approach displayed reduction of PSM especially at the apex and in tumors with extra- capsular extension. Prospective randomized studies including bigger cohorts of patients with longer follow up are mandatory to confirm these results

Enhanced Ultrasound Visualization for Procedure Guidance

Intra-cardiac procedures often involve fast-moving anatomic structures with large spatial extent and high geometrical complexity. Real-time visualization of the moving structures and instrument-tissue contact is crucial to the success of these procedures. Real-time 3D ultrasound is a promising modality for procedure guidance as it offers improved spatial orientation information relative to 2D ultrasound. Imaging rates at 30 fps enable good visualization of instrument-tissue interactions, far faster than the volumetric imaging alternatives (MR/CT). Unlike fluoroscopy, 3D ultrasound also allows better contrast of soft tissues, and avoids the use of ionizing radiation.Engineering and Applied Science