MP8-01 Can We Treat Female Recurrent Urinary Tract Infection Without Urine Culture? Comparative Analysis of Bacteriology and Susceptibility Profile (original) (raw)

In vivo MR elastography of the prostate gland using a transurethral actuator

Magnetic Resonance in Medicine, 2009

Conventional approaches for MR elastography (MRE) using surface drivers have difficulty achieving sufficient shear wave propagation in the prostate gland due to attenuation. In this study we evaluate the feasibility of generating shear wave propagation in the prostate gland using a transurethral device. A novel transurethral actuator design is proposed, and the performance of this device was evaluated in gelatin phantoms and in a canine prostate gland. All MRI was performed on a 1.5T MR imager using a conventional gradient-echo MRE sequence. A piezoceramic actuator was used to vibrate the transurethral device along its length. Shear wave propagation was measured transverse and parallel to the rod at frequencies between 100 and 250 Hz in phantoms and in the prostate gland. The shear wave propagation was cylindrical, and uniform along the entire length of the rod in the gel experiments. The feasibility of transurethral MRE was demonstrated in vivo in a canine model, and shear wave propagation was observed in the prostate gland as well as along the rod. These experiments demonstrate the technical feasibility of transurethral MRE in vivo. Further development of this technique is warranted. Magn Reson Med 62: 665-671, 2009.

Transperineal prostate MR elastography: Initial in vivo results

Magnetic Resonance in Medicine, 2013

This article presents a new approach to magnetic resonance elastography of the prostate using transperineal mechanical excitation. This approach is validated using a prostate elasticity phantom and in vivo studies of healthy volunteers. It is demonstrated that the transperineal approach can generate shear wave amplitudes on the order of 6-30 mm in the midgland region. The driver was implemented using an electromagnetic actuator with a hydraulic transmission system. The magnetic resonance elastography acquisition time has been reduced significantly by using a ''second harmonic'' approach. Displacement fields are processed using the established three-dimensional local frequency estimation algorithm. The three-dimensional curl-based direct inversion was used to calculate the local wavelength. The traveling wave expansion algorithm was used to reconstruct the wave damping image for one case. Using the proposed method, it was possible to resolve lesions of 0.5 cc in the phantom study. Repeatability experiments were performed and analyzed. The results from this study indicate that transperineal magnetic resonance elastography-without an endorectal coil-is a suitable candidate for a patient study involving multiparametric magnetic resonance imaging of prostate cancer, where magnetic resonance elastography may provide additional information for improved diagnosis and image-based surveillance. Magn Reson Med 000:000-000, 2012. V C 2012 Wiley Periodicals, Inc.

Magnetic resonance imaging (MRI)-guided transurethral ultrasound therapy of the prostate: a preclinical study with radiological and pathological correlation using customised MRI-based moulds

BJU International, 2013

• To characterise the feasibility and safety of a novel transurethral ultrasound (US)-therapy device combined with real-time multi-plane magnetic resonance imaging (MRI)-based temperature monitoring and temperature feedback control, to enable spatiotemporally precise regional ablation of simulated prostate gland lesions in a preclinical canine model. • To correlate ablation volumes measured with intra-procedural cumulative thermal damage estimates, post-procedural MRI, and histopathology. • Three dogs were treated with three targeted ablations each, using a prototype MRI-guided transurethral US-therapy system (Philips Healthcare, Vantaa, Finland). • MRI provided images for treatment planning, guidance, real-time multi-planar thermometry, as well as post-treatment evaluation of efficacy. • After treatment, specimens underwent histopathological analysis to determine the extent of necrosis and cell viability. • Statistical analyses (Pearson's correlation, Student's t-test) were used to evaluate the correlation between ablation volumes measured with intra-procedural cumulative thermal damage estimates, post-procedural MRI, and histopathology. • MRI combined with a transurethral US-therapy device enabled multi-planar temperature monitoring at the target as well as in surrounding tissues, allowing for safe, targeted, and controlled ablations of prescribed lesions.

Characterisation of Prostate Lesions Using Transrectal Shear Wave Elastography (SWE) Ultrasound Imaging: A Systematic Review

Cancers

Background: ultrasound-based shear wave elastography (SWE) can non-invasively assess prostate tissue stiffness. This systematic review aims to evaluate SWE for the detection of prostate cancer (PCa) and compare diagnostic estimates between studies reporting the detection of all PCa and clinically significant PCa (csPCa). Methods: a literature search was performed using the MEDLINE, EMBASE, Cochrane Library, ClinicalTrials.gov, and CINAHL databases. Studies evaluating SWE for the detection of PCa using histopathology as reference standard were included. Results: 16 studies including 2277 patients were included for review. Nine studies evaluated SWE for the detection of PCa using systematic biopsy as a reference standard at the per-sample level, with a pooled sensitivity and specificity of 0.85 (95% CI = 0.74–0.92) and 0.85 (95% CI = 0.75–0.91), respectively. Five studies evaluated SWE for the detection of PCa using histopathology of radical prostatectomy (RP) specimens as the referen...

Advancements in MR Imaging of the Prostate: From Diagnosis to Interventions

RadioGraphics, 2011

Prostate cancer is the most frequently diagnosed cancer in males and the second leading cause of cancer-related death in men. Assessment of prostate cancer can be divided into detection, localization, and staging; accurate assessment is a prerequisite for optimal clinical management and therapy selection. Magnetic resonance (MR) imaging has been shown to be of particular help in localization and staging of prostate cancer. Traditional prostate MR imaging has been based on morphologic imaging with standard T1-weighted and T2-weighted sequences, which has limited accuracy. Recent advances include additional functional and physiologic MR imaging techniques (diffusionweighted imaging, MR spectroscopy, and perfusion imaging), which allow extension of the obtainable information beyond anatomic assessment. Multiparametric MR imaging provides the highest accuracy in diagnosis and staging of prostate cancer. In addition, improvements in MR imaging hardware and software (3-T vs 1.5-T imaging) continue to improve spatial and temporal resolution and the signal-to-noise ratio of MR imaging examinations. Another recent advancement in the field is MR imaging guidance for targeted prostate biopsy, which is an alternative to the current standard of transrectal ultrasonographyguided systematic biopsy. ©

Performance characteristics of transrectal shear wave elastography (SWE) imaging in the evaluation of clinically localised prostate cancer: a prospective study

The Journal of urology, 2018

To test the diagnostic accuracy of SWE for the detection and phenotypic characterisation of PCa compared with whole-mount radical prostatectomy histopathology. This was a prospective protocol-driven diagnostic accuracy study. 212 consecutive men undergoing laparoscopic radical prostatectomy (LRP) for clinically localised PCa were recruited into the study. Quantitative stiffness data of the prostate gland was obtained in each patient using an endocavitary transrectal transducer before LRP and compared with detailed histopathological examination of radical prostatectomy specimen using 3-D printing mold based technology ensuring improved image-histology orientation. Receiver operator characteristic curves (ROC) were assessed between the groups. and limitations: Quantitative stiffness data estimated in kilopascals (kPa) was significantly higher in malignant compared with benign areas. With a cut-off value of 82.6 kPa, sensitivity and specificity of SWE were 96.8% and 67.8%, respectively...

Quantitative transrectal shear wave elastography undergoing salvage extraperitoneal laparoscopic radical prostatectomy following failed radiotherapy

Surgical endoscopy, 2018

To evaluate pre-surgical quantitative transrectal shear wave elastography (SWE) in the detection and characterisation of radioresistant prostate cancer. Twelve men with recurrent prostate cancer following external beam radiotherapy were included in a prospective protocol-driven study. All underwent MR imaging and quantitative shear wave elastographic assessment of recurrent disease prior to salvage laparoscopic radical prostatectomy procedures. Images were used to construct 3D mold printing and histopathological processing of surgical specimen. Statistical analyses including ROC were generated using software programmes. There were 48 cancer foci identified on final histopathology using patient-specific mold-based approach in 12 patients. Mean number of lesion was 3.4 (range 2-4). Quantitative transrectal SWE showed a sensitivity and specificity 0.77 (95% CI 0.627-0.880) and 0.82 (95% CI 0.642-0.942), respectively. The diagnostic accuracy increased with increasing size of the lesions...

MRI-compatible transurethral ultrasound system for the treatment of localized prostate cancer using rotational control

Medical Physics, 2008

Magnetic resonance imaging ͑MRI͒-guided transurethral ultrasound therapy is a potential minimally invasive treatment for localized prostate cancer offering precise targeting of tissue within the gland, short treatment times, and the capability to quantify the spatial heating pattern delivered during therapy. A significant challenge in MRI-guided ultrasound therapy is the design and construction of MRI-compatible equipment capable of operation in a closed-bore MR imager. We describe a prototype system developed for MRI-guided transurethral ultrasound therapy and characterize the performance of the different components including the heating applicator design, rotational motor, and radio frequency electronics. The ultrasound heating applicator described in this study incorporates a planar transducer and is capable of producing high intensity ultrasound energy in a localized region of tissue. Results demonstrated that the heating applicator exhibits excellent MRI-compatibility, enabling precise MR temperature measurements to be acquired as close as 6 mm from the device. Simultaneous imaging and rotational motion was also possible during treatment using a motor based on piezoelectric actuators. Heating experiments performed in both phantoms and in a canine model with the prototype system verified the capability to perform simultaneous MR imaging and therapy delivery with this system. Real-time control over therapy using MR temperature measurements acquired during heating can be implemented to achieve precise patterns of thermal damage within the prostate gland. The technical feasibility of using the system developed in this study for MRI-guided transurethral ultrasound therapy in a closed-bore MR imager has been demonstrated.

Design and Preliminary Accuracy Studies of an MRI-Guided Transrectal Prostate Intervention System

2007

This paper reports a novel system for magnetic resonance imaging (MRI) guided transrectal prostate interventions, such as needle biopsy, fiducial marker placement, and therapy delivery. The system utilizes a hybrid tracking method, comprised of passive fiducial tracking for initial registration and subsequent incremental motion measurement along the degrees of freedom using fiber-optical encoders and mechanical scales. Targeting accuracy of the system is evaluated in prostate phantom experiments. Achieved targeting accuracy and procedure times were found to compare favorably with existing systems using passive and active tracking methods. Moreover, the portable design of the system using only standard MRI image sequences and minimal custom scanner interfacing allows the system to be easily used on different MRI scanners.