Prostate biopsies assisted by comanipulated probe-holder: first in man

International audiencePurpose: a comanipulator for assisting endorectal prostate biopsies is evaluated through a first-in man clinical trial. This lightweight system, based on conventional robotic components, possesses 6 degrees of freedom. It uses 3 electric motors and 3 brakes. It features a free mode, where its low friction and inertia allow for natural manipulation of the probe and a locked mode, exhibiting both a very low stiffness and a high steady state precision. Methods: Clinical trials focusing on the free mode and the locked mode of the robot are presented. The objective is to evaluate the practical usability and performance of the robot during clinical procedures. A research protocol for a prospective randomized clinical trial has been designed. Its specific goal is to compare the accuracy of biopsies performed with and without the assistance of the comanipulator. Results:The accuracy is compared between biopsies performed with and without the assistance of the comanipulator, across the 10 first patients included in the trial. Results show a statistically significant increase of the precision.. This work is partially funded french state funds managed by the ANR within the Investissements d'Avenir programme (Labex CAMI) under reference ANR-11-LABX-0004. 2 Marie-Aude Vitrani et al

Preoperative prostate biopsy and multiparametric magnetic resonance imaging: Reliability in detecting prostate cancer

Purpose The aim of the study was to analyse and compare the ability of multiparametric magnetic resonance imaging (mp–MRI) and prostate biopsy (PB) to correctly identify tumor foci in patients undergoing radical prostatectomy (RP) for prostate cancer (PCa). Materials and Methods 157 patients with clinically localised PCa with a PSA <10 ng/mL and a negative DRE diagnosed on the first (12 samples, Group A) or second (18 samples, Group B) PB were enrolled at our institution. All patients underwent mp-MRI with T2-weighted images, diffusion-weighted imaging, dynamic contrast enhanced-MRI prior to RP. A map of comparison describing each positive biopsy sample was created for each patient, with each tumor focus shown on the MRI and each lesion present on the definitive histological examination in order to compare tumor detection and location. The sensitivity of mp-MRI and PB for diagnosis was compared using Student’s t-test. The ability of the two exams to detect the prevalence of Gleason pattern 4 in the identified lesions was compared using a chi-square test. Results Overall sensitivity of PB and mp-MRI to identify tumor lesion was 59.4% and 78.9%, respectively (p<0.0001). PB missed 144/355 lesions, 59 of which (16.6%) were significant. mp-MRI missed 75/355 lesions, 12 of which (3.4%) were significant. No lesions with a GS≥8 were missed. Sensitivity of PB and mp-MRI to detect the prevalence of Gleason pattern 4 was 88.2% and 97.4%, respectively. Conclusions mp-MRI seems to identify more tumor lesions than PB and to provide more information concerning tumor characteristics

Multiparametric 3 Tesla magnetic resonance imaging as a clinical tool to characterize prostate cancer

Scientists have come a long way in understanding prostate cancer as a disease and how its progression affects the men who develop it. Prostate adenocarcinoma may be present without causing clinical symptoms. Prostate cancer may metastasize, which increases the likelihood of fatality. The cause of the disease is still not completely clear, but genetics, race, tissue damage, history of previous infections, diet, and environmental influences appear to play a role in its development. Magnetic resonance imaging (MRI) has become an excellent clinical tool to characterize prostate cancer without the use of ionizing radiation or surgery. It is concluded that MRI is the optimal imaging modality to achieve detection, characterization, and staging of intracapsular and extracapsular prostate disease. The advances in MRI technology, particularly 3 Tesla, allows for reduced surgical intervention thus improving quality of life for patients with the disease

A non-invasive image based system for early diagnosis of prostate cancer.

Prostate cancer is the second most fatal cancer experienced by American males. The average American male has a 16.15% chance of developing prostate cancer, which is 8.38% higher than lung cancer, the second most likely cancer. The current in-vitro techniques that are based on analyzing a patients blood and urine have several limitations concerning their accuracy. In addition, the prostate Specific Antigen (PSA) blood-based test, has a high chance of false positive diagnosis, ranging from 28%-58%. Yet, biopsy remains the gold standard for the assessment of prostate cancer, but only as the last resort because of its invasive nature, high cost, and potential morbidity rates. The major limitation of the relatively small needle biopsy samples is the higher possibility of producing false positive diagnosis. Moreover, the visual inspection system (e.g., Gleason grading system) is not quantitative technique and different observers may classify a sample differently, leading to discrepancies in the diagnosis. As reported in the literature that the early detection of prostate cancer is a crucial step for decreasing prostate cancer related deaths. Thus, there is an urgent need for developing objective, non-invasive image based technology for early detection of prostate cancer. The objective of this dissertation is to develop a computer vision methodology, later translated into a clinically usable software tool, which can improve sensitivity and specificity of early prostate cancer diagnosis based on the well-known hypothesis that malignant tumors are will connected with the blood vessels than the benign tumors. Therefore, using either Diffusion Weighted Magnetic Resonance imaging (DW-MRI) or Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI), we will be able to interrelate the amount of blood in the detected prostate tumors by estimating either the Apparent Diffusion Coefficient (ADC) in the prostate with the malignancy of the prostate tumor or perfusion parameters. We intend to validate this hypothesis by demonstrating that automatic segmentation of the prostate from either DW-MRI or DCE-MRI after handling its local motion, provides discriminatory features for early prostate cancer diagnosis. The proposed CAD system consists of three majors components, the first two of which constitute new research contributions to a challenging computer vision problem. The three main components are: (1) A novel Shape-based segmentation approach to segment the prostate from either low contrast DW-MRI or DCE-MRI data; (2) A novel iso-contours-based non-rigid registration approach to ensure that we have voxel-on-voxel matches of all data which may be more difficult due to gross patient motion, transmitted respiratory effects, and intrinsic and transmitted pulsatile effects; and (3) Probabilistic models for the estimated diffusion and perfusion features for both malignant and benign tumors. Our results showed a 98% classification accuracy using Leave-One-Subject-Out (LOSO) approach based on the estimated ADC for 30 patients (12 patients diagnosed as malignant; 18 diagnosed as benign). These results show the promise of the proposed image-based diagnostic technique as a supplement to current technologies for diagnosing prostate cancer

New Mechatronic Systems for the Diagnosis and Treatment of Cancer

Both two dimensional (2D) and three dimensional (3D) imaging modalities are useful tools for viewing the internal anatomy. Three dimensional imaging techniques are required for accurate targeting of needles. This improves the efficiency and control over the intervention as the high temporal resolution of medical images can be used to validate the location of needle and target in real time. Relying on imaging alone, however, means the intervention is still operator dependent because of the difficulty of controlling the location of the needle within the image. The objective of this thesis is to improve the accuracy and repeatability of needle-based interventions over conventional techniques: both manual and automated techniques. This includes increasing the accuracy and repeatability of these procedures in order to minimize the invasiveness of the procedure. In this thesis, I propose that by combining the remote center of motion concept using spherical linkage components into a passive or semi-automated device, the physician will have a useful tracking and guidance system at their disposal in a package, which is less threatening than a robot to both the patient and physician. This design concept offers both the manipulative transparency of a freehand system, and tremor reduction through scaling currently offered in automated systems. In addressing each objective of this thesis, a number of novel mechanical designs incorporating an remote center of motion architecture with varying degrees of freedom have been presented. Each of these designs can be deployed in a variety of imaging modalities and clinical applications, ranging from preclinical to human interventions, with an accuracy of control in the millimeter to sub-millimeter range

Estrus Cycle Monitoring in Wild Mammals: Challenges and Perspectives

The knowledge of reproductive physiology is of paramount importance to guide reproductive management and to make possible future application of assisted reproduction techniques (ARTs) aiming ex situ conservation of wild mammals. Nevertheless, information on the basic reproductive aspects of wild mammals remain scarce, and appropriate management practices have not yet been developed for all the species. This chapter discusses the methods most currently used for reproductive monitoring in wild females. Additionally, the difficulties regarding their use in different species and the possibilities of these procedures in captivity or in free-living mammals are addressed

Melatonin Implants during Pregnancy on Maternal Hemodynamics and Growth of Offspring in Beef Cattle

Melatonin is a strong antioxidant that has previously been observed to increase uteroplacental blood flow and increase postnatal calf growth when supplemented during gestation. The objective of the current study was to examine the effects of melatonin implants on uterine blood flow and subsequent offspring growth. Commercial beef heifers and cows were artificially inseminated and assigned to one of two treatment groups supplemented with (MEL) or without (CON) melatonin from days 180 to 240 of gestation. Total uterine artery blood flow was increased in MEL- versus CON-treated cattle. Fetal and birth weight were not different between treatments. However, at castration, body weight was increased in calves from MEL-treated dams compared with CON-treated dams. Further research on placental vascularization and the mechanism in which melatonin impacts angiogenic factors is necessary to understand the relationship between melatonin and compensatory growth that occurs in postnatal offspring