Transrectal Ultrasound System Research Articles

Contrast-Specific Spherical Lesion Phantoms and Ancillary Analysis Software for the Objective Evaluation of Transrectal Ultrasound System Contrast Detectability.

Brachytherapy is an efficacious treatment option because of its benefits for patient recovery, dose localization and conformity, but these favorable outcomes can be ensured only if the transrectal ultrasound (TRUS) system is optimized for the specific application of ultrasound-guided prostate brachytherapy. The ability to delineate the prostate from surrounding tissue during TRUS-guided prostate brachytherapy is vital for treatment planning, and consequently, so is the contrast resolution. This study describes the development of task-specific contrast-detail phantoms with clinically relevant contrast and spherical target sizes for contrast-detail performance evaluation of TRUS systems used in the brachytherapy procedure. The procedure for objective assessment of the contrast detectability of the TRUS systems is also described; a program was developed in MATLAB (R2017a, The MathWorks, Natick, MA, USA) to quantitatively analyze image quality in terms of the lesion signal-to-noise ratio (LSNR) and validated with representative control test images. The LSNR of the Hitachi EUB-7500A (2013, Hitachi, Ltd, Tokyo, Japan) TRUS system was measured on sagittal and transverse TRUS images of the contrast-detail phantoms described in this work. Results revealed the efficacy of the device as an image quality evaluation tool and the impact of the size, depth and relative contrast of the targets to the surrounding tissue on the contrast detectability of a TRUS system for both transducer arrays. The MATLAB program objectively measured the contrast detectability of the TRUS system and has the potential to determine optimized imaging parameters that could be designed as part of standardization of the imaging protocol used in TRUS-guided prostate brachytherapy for prostate cancer.

Toward a 3D transrectal ultrasound system for verification of needle placement during high-dose-rate interstitial gynecologic brachytherapy.

Treatment for gynecologic cancers, such as cervical, recurrent endometrial, and vaginal malignancies, commonly includes external-beam radiation and brachytherapy. In high-dose-rate (HDR) interstitial gynecologic brachytherapy, radiation treatment is delivered via hollow needles that are typically inserted through a template on the perineum with a cylinder placed in the vagina for stability. Despite the need for precise needle placement to minimize complications and provide optimal treatment, there is no standard intra-operative image-guidance for this procedure. While some image-guidance techniques have been proposed, including magnetic resonance (MR) imaging, X-ray computed tomography (CT), and two-dimensional (2D) transrectal ultrasound (TRUS), these techniques have not been widely adopted. In order to provide intra-operative needle visualization and localization during interstitial brachytherapy, we have developed a three-dimensional (3D) TRUS system. This study describes the 3D TRUS system and reports on the system validation and results from a proof-of-concept patient study. To obtain a 3D TRUS image, the system rotates a conventional 2D endocavity transducer through 170 degrees in 12s, reconstructing the 2D frames into a 3D image in real-time. The geometry of the reconstruction was validated using two geometric phantoms to ensure the accuracy of the linear measurements in each of the image coordinate directions and the volumetric accuracy of the system. An agar phantom including vaginal and rectal canals, as well as a model uterus and tumor, was designed and used to test the visualization and localization of the interstitial needles under idealized conditions by comparing the needles' positions between the 3D TRUS scan and a registered MR image. Five patients undergoing HDR interstitial gynecologic brachytherapy were imaged using the 3D TRUS system following the insertion of all needles. This image was manually, rigidly registered to the clinical postinsertion CT scan based on the vaginal cylinder of the needle template. The positions of the tips and the trajectory of the needle paths were compared between the modalities. The observed geometric errors of the system were ≤0.3mm in each of the three coordinate planes of the 3D US image and the mean measured volumetric error was 0.10cm3 . In the phantom study, the mean needle tip difference was 1.54±0.71 mm and the mean trajectory difference was 0.94±0.89 degrees (n=14). In the invivo study, a total of 73 needles were placed, of which 88% of needles were visible and 79% of tips were identifiable in the 3D TRUS images. Six of the nine needles that were not visible were due to shadowing artifacts created by the presence of the vaginal cylinder of the needle template. The mean distance between corresponding needle tips in the two modalities was 3.82±1.86mm and the mean trajectory difference was 3.04±1.63 degrees for the five patients. In this proof-of-concept study, the 3D TRUS system allowed for localization of needles not obscured by shadowing artifacts, providing a method for visualizing needles intra-operatively during HDR interstitial brachytherapy of gynecologic cancers and providing the potential for 3D image-guidance.

Targeted MRI/TRUS fusion-guided biopsy in men with previous prostate biopsies using a novel registration software and multiparametric MRI PI-RADS scores: first results.

To evaluate a novel system for MRI/TRUS fusion-guided biopsy for detection of prostate cancer (PCa) in patients with previous negative prostate biopsy and determine diagnostic accuracy when using the Prostate Imaging Reporting and Data System (PI-RADS) for multiparametric magnetic resonance imaging (mpMRI) as proposed by the European Society of Urogenital Radiology. Thirty-nine men with clinical suspicion of PCa and history of previous prostate biopsy underwent mpMRI on a 3-T MRI. In total, 72 lesions were evaluated by the consensus of two radiologists. PI-RADS scores for each MRI sequence, the sum of the PI-RADS scores and the global PI-RADS were determined. MRI/TRUS fusion-guided targeted biopsy was performed using the BioJet™ software combined with a transrectal ultrasound system. Image fusion was based on rigid registration. PI-RADS scores of the dominant lesion were compared with histopathological results. Diagnostic accuracy was determined using receiver operating characteristic curve analysis. MRI/TRUS fusion-guided biopsy was reliable and successful for 71 out of 72 lesions. The global PI-RADS score of the dominant lesion was significantly higher in patients with PCa (4.0 ± 1.3) compared to patients with negative histopathology (2.6 ± 0.8; p = 0.0006). Using a global PI-RADS score cut-off ≥4, a sensitivity of 85 %, a specificity of 82 % and a negative predictive value of 92 % were achieved. The described fusion system is dependable and efficient for targeted MRI/TRUS fusion-guided biopsy. mpMRI PI-RADS scores combined with a novel real-time MRI/TRUS fusion system facilitate sufficient diagnosis of PCa with high sensitivity and specificity.

Intraoperative Registered Transrectal Ultrasound Guidance for Robot-Assisted Laparoscopic Radical Prostatectomy

To provide unencumbered real-time ultrasound image guidance during robot-assisted laparoscopic radical prostatectomy, we developed a robotic transrectal ultrasound system that tracks the da Vinci® Surgical System instruments. We describe our initial clinical experience with this system. After an evaluation in a canine model, 20 patients were enrolled in the study. During each procedure the transrectal ultrasound transducer was manually positioned using a brachytherapy stabilizer to provide good imaging of the prostate. Then the transrectal ultrasound was registered to the da Vinci robot by a previously validated procedure. Finally, automatic rotation of the transrectal ultrasound was enabled such that the transrectal ultrasound imaging plane safely tracked the tip of the da Vinci instrument controlled by the surgeon, while real-time transrectal ultrasound images were relayed to the surgeon at the da Vinci console. Tracking was activated during all critical stages of the surgery. The transrectal ultrasound robot was easy to set up and use, adding 7 minutes (range 5 to 14) to the procedure. It did not require an assistant or additional control devices. Qualitative feedback was acquired from the surgeons, who found transrectal ultrasound useful in identifying the urethra while passing the dorsal venous complex suture, defining the prostate-bladder interface during bladder neck dissection, identifying the seminal vesicles and their location with respect to the rectal wall, and identifying the distal prostate boundary at the apex. Real-time, registered robotic transrectal ultrasound guidance with automatic instrument tracking during robot-assisted laparoscopic radical prostatectomy is feasible and potentially useful. The results justify further studies to establish whether the approach can improve procedure outcomes.

MP37-17 INTRAOPERATIVE REGISTERED TRANSRECTAL ULTRASOUND GUIDANCE FOR ROBOT-ASSISTED LAPAROSCOPIC RADICAL PROSTATECTOMY: A 20 PATIENT STUDY

You have accessJournal of UrologyTechnology & Instruments: Robotics - Benign & Malignant Disease1 Apr 2014MP37-17 INTRAOPERATIVE REGISTERED TRANSRECTAL ULTRASOUND GUIDANCE FOR ROBOT-ASSISTED LAPAROSCOPIC RADICAL PROSTATECTOMY: A 20 PATIENT STUDY Omid Mohareri, Joseph Ischia, Peter Black, Larry Goldenberg, Julio Lobo, Caitlin Schneider, and Septimiu Salcudean Omid MohareriOmid Mohareri More articles by this author , Joseph IschiaJoseph Ischia More articles by this author , Peter BlackPeter Black More articles by this author , Larry GoldenbergLarry Goldenberg More articles by this author , Julio LoboJulio Lobo More articles by this author , Caitlin SchneiderCaitlin Schneider More articles by this author , and Septimiu SalcudeanSeptimiu Salcudean More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.1254AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES This work demonstrates, for the first time, the clinical application of a robotic transrectal ultrasound (TRUS) system calibrated to the da Vinci surgical system, for real-time monitoring of the prostate and periprostatic anatomy from the surgeon’s console during robot-assisted laparoscopic radical prostatectomy (RALRP). METHODS Twenty patients (60.27±4.6 years of age; 33.16±11.78 cc prostate volume) with organ-confined prostate cancer undergoing RALRP at our institution agreed to participate in this CREB-approved (clinical research ethics board) study. Before docking the da Vinci system, our robotic TRUS system was attached to the foot of the operating table and a TRUS transducer was placed and adjusted to provide optimal transverse and sagittal images of the prostate and its surrounding structures. Furthermore, once the anterior surface of the prostate was visible to the surgeon, a registration technique was performed between the TRUS transducer and the da Vinci instrument, to enable the TRUS imaging plane to automatically track the tip of the da Vinci instrument. The mean duration of calibration procedure was 137.1 ± 29.59 sec. After the registration, movements of the instrument tip was constantly visible in the ultrasound image, showing the location of the tools relative to the target anatomy. RESULTS During each procedure, the TRUS robot was used to remotely control the rotation angle and insertion depth of the TRUS transducer and real-time TRUS images were relayed to the surgeon at the console using the TilePro feature of the da Vinci. No major complications occurred and the TRUS remained in place until the end of procedures. The TRUS imaging was found useful in the following stages: identifying urethra while passing the dorsal venous complex suture, defining the prostate-bladder interface during posterior and anterior bladder neck dissection, identifying the lateral edges of the seminal vesicles and their location with respect to the rectal wall, and identifying the prostate boundary at the apex. Automatic tool tracking was activated during all critical stages of the surgery to facilitate real-time TRUS navigation using the same instruments being used during the procedure. CONCLUSIONS We conclude that real-time TRUS imaging can be deployed and used easily during surgery, can be registered to the da Vinci surgical system instruments with high accuracy in a short time for remote control from the surgeon console, and it can provide the console surgeon with valuable anatomic information, aiming to improve procedure outcomes. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e398-e399 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Omid Mohareri More articles by this author Joseph Ischia More articles by this author Peter Black More articles by this author Larry Goldenberg More articles by this author Julio Lobo More articles by this author Caitlin Schneider More articles by this author Septimiu Salcudean More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Multi-parametric 3D quantitative ultrasound vibro-elastography imaging for detecting palpable prostate tumors.

In this article, we describe a system for detecting dominant prostate tumors, based on a combination of features extracted from a novel multi-parametric quantitative ultrasound elastography technique. The performance of the system was validated on a data-set acquired from n = 10 patients undergoing radical prostatectomy. Multi-frequency steady-state mechanical excitations were applied to each patient's prostate through the perineum and prostate tissue displacements were captured by a transrectal ultrasound system. 3D volumetric data including absolute value of tissue elasticity, strain and frequency-response were computed for each patient. Based on the combination of all extracted features, a random forest classification algorithm was used to separate cancerous regions from normal tissue, and to compute a measure of cancer probability. Registered whole mount histopathology images of the excised prostate gland were used as a ground truth of cancer distribution for classifier training. An area under receiver operating characteristic curve of 0.82 +/- 0.01 was achieved in a leave-one-patient-out cross validation. Our results show the potential of multi-parametric quantitative elastography for prostate cancer detection for the first time in a clinical setting, and justify further studies to establish whether the approach can have clinical use.

2031 ENHANCED TUMOUR SAMPLING AND GLEASON GRADING THROUGH FUSION OF MRI TO 3D TRANSRECTAL ULTRASOUND (TRUS) BIOPSY

You have accessJournal of UrologyImaging/Radiology: Uroradiology I1 Apr 20122031 ENHANCED TUMOUR SAMPLING AND GLEASON GRADING THROUGH FUSION OF MRI TO 3D TRANSRECTAL ULTRASOUND (TRUS) BIOPSY Derek W. Cool, Cesare Romagnoli, Jonathan I. Izawa, Joseph Chin, Lori Gardi, Aaron D. Ward, and Aaron Fenster Derek W. CoolDerek W. Cool London, Canada More articles by this author , Cesare RomagnoliCesare Romagnoli London, Canada More articles by this author , Jonathan I. IzawaJonathan I. Izawa London, Canada More articles by this author , Joseph ChinJoseph Chin London, Canada More articles by this author , Lori GardiLori Gardi London, Canada More articles by this author , Aaron D. WardAaron D. Ward London, Canada More articles by this author , and Aaron FensterAaron Fenster London, Canada More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.2195AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES MRI is superior to TRUS for visualization of prostate adenocarcinoma (PCa). We compare the clinical impact of real-time fusion of MRI and intra-biopsy 3D TRUS for targeted biopsy of suspicious MRI lesions with the standard systematic biopsy for PCa detection and grading. METHODS A prospective, MRI-3D TRUS biopsy study enrolled 40 patients with PSA 2-10 ± DRE findings, but no prior histopathological diagnosis of PCa. 3T MRIs with endorectal coil were performed prior to biopsy and interpreted by an expert uroradiologist. Intra-biopsy fusion of the MRI and 3D TRUS images was performed and biopsy cores were targeted toward each MRI-suspicious lesion using a mechanical 3D TRUS system developed in our laboratory. A standard sextant, 12-core set of random biopsies was also performed and used as an internal control. RESULTS Targeted biopsy cores using MRI-3D TRUS fusion had substantially higher rates of PCa (28.1%) compared to random, sextant cores (9.4%). For patients in whom PCa was detected in both targeted and random sampling, the targeted biopsies contained a significantly higher (p<0.05) percentage of PCa per core (44±23%) than the randomly sampled cores (27±24%), suggesting that the targeted cores more thoroughly sampled the underlying tumor. In total, prostate cancer was biopsy confirmed in 14 patients; however, even with retrospective analysis, only 9 of these patients had abnormal MRI findings all of whom were successfully sampled with targeted MRI-3D TRUS fusion. The remaining 5 patients were detected through random sampling. In 3 of the 9 patients, MRI-targeted cores detected a higher Gleason grade than the random cores. Of the 6 patients who underwent prostatectomy, none of the targeted cores had Gleason upgrading on final pathology, while 2 patients with Gleason 6 on random biopsy were upgraded to Gleason 7. CONCLUSIONS MRI-3D TRUS fusion allows for superior sampling of MRI-visible PCa and may identify high-grade disease missed by systematic sampling. Small, lower-grade PCa may not be visible on MRI, suggesting that targeted biopsy may not be sufficient to replace sextant biopsy. However, MRI-3D TRUS fusion may be important for patients with low-grade disease considering conservative or focal therapy. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e819-e820 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Derek W. Cool London, Canada More articles by this author Cesare Romagnoli London, Canada More articles by this author Jonathan I. Izawa London, Canada More articles by this author Joseph Chin London, Canada More articles by this author Lori Gardi London, Canada More articles by this author Aaron D. Ward London, Canada More articles by this author Aaron Fenster London, Canada More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

3-Dimensional Elastic Registration System of Prostate Biopsy Location by Real-Time 3-Dimensional Transrectal Ultrasound Guidance With Magnetic Resonance/Transrectal Ultrasound Image Fusion

We determined the accuracy of the novel Urostation 3-dimensional transrectal ultrasound system (Koelis, La Tranche, France) for image based mapping biopsies in a prostate phantom. The system is capable of 1) registering the 3-dimensional location of each biopsy track in the 3-dimensional prostate volume data and 2) performing elastic image fusion of transrectal ultrasound with magnetic resonance imaging. We used 3 CIRS-053 prostate phantoms containing 3 hypoechoic lesions to perform ultrasound guided biopsy and 3 CIRS-066 phantoms (Computerized Imaging Reference Systems, Norfolk, Virginia) containing 3 isoechoic but magnetic resonance imaging visible lesions to perform magnetic resonance fusion guided biopsy. Three targeted biopsies were done per lesion. Each biopsy tract was injected with gadolinium based magnetic resonance contrast mixed with india ink. Phantoms were then subjected to 1 mm slice magnetic resonance imaging and serial step sectioning to assess the accuracy of targeted biopsy. A total of 27 ultrasound guided biopsies were targeted into 9 hypoechoic lesions. All 27 biopsies (100%) successfully hit the target lesion. For hypoechoic lesions mean ± SD procedural targeting error was 1.52 ± 0.78 mm and system registration error was 0.83 mm, resulting in an overall error of 2.35 mm. Of the 27 magnetic resonance fusion biopsies 24 (84%) hit the lesion. For isoechoic lesions mean procedural targeting error was 2.09 ± 1.28 mm, resulting in an overall error of 2.92 mm. The novel, computer assisted, 3-dimensional transrectal ultrasound biopsy localization system achieved encouraging accuracy with less than 3 mm error for targeting hypoechoic and isoechoic lesions. The ability to register actual biopsy trajectory and perform elastic magnetic resonance/ultrasound image fusion is a significant advantage for future focal therapy application.

In vitro validation of a 3-dimensional transrectal ultrasound system for prostate biopsiess

Introduction: Transrectal ultrasound (TRUS) prostate biopsy (Bx) is currently confined to 2D information to both target and record 3D Bx locations. Accurate placement of Bx needles cannot be verified without 3D information, and recording Bx sites in 2D does not provide sufficient information to accurately guide the high incidence of repeat Bx. We have designed a 3D TRUS prostate Bx system that augments the current 2D TRUS system and provides tools for biopsy-planning, needle guidance, and recording of the biopsy core locations entirely in 3D.&#x0D; Methods: Our Bx system displays a 3D model of the patient’s prostate, which is generated intra-procedure from a collection of 2D TRUS images, representative of the particular prostate shape. Bx targets are selected, needle guidance is facilitated, and 3D Bx sites are recorded within the 3D context of the prostate model. The complete 3D Bx system was validated, in vitro, by performing standard ten-core Bx on anatomical phantoms of two patient’s prostates. The accuracy of the needle-guidance, Bx location recording, and 3D model volume and surface topology were validated against a CT gold standard. &#x0D; Results: The Bx system successfully reconstructed the 3D patient prostate models with a mean volume error of 3.2 ± 7.6%. Using the 3D system, needles were accurately guided to the pre-determined targets with a mean error of 2.26 ± 1.03 mm and the 3D locations of the Bx cores were accurately recorded with a mean distance error of 1.47 ± 0.79 mm. &#x0D; Conclusion: We have successfully developed a 3D TRUS prostate biopsy system and validated the system in vitro. A pilot study has been initiated to apply the system clinically.

Needle steering for 3D TRUS-guided robot-aided brachytherapy

To provide unencumbered real-time ultrasound image guidance during robot-assisted laparoscopic radical prostatectomy, we developed a robotic transrectal ultrasound system that tracks the da Vinci® Surgical System instruments. We describe our initial clinical experience with this system.After an evaluation in a canine model, 20 patients were enrolled in the study. During each procedure the transrectal ultrasound transducer was manually positioned using a brachytherapy stabilizer to provide good imaging of the prostate. Then the transrectal ultrasound was registered to the da Vinci robot by a previously validated procedure. Finally, automatic rotation of the transrectal ultrasound was enabled such that the transrectal ultrasound imaging plane safely tracked the tip of the da Vinci instrument controlled by the surgeon, while real-time transrectal ultrasound images were relayed to the surgeon at the da Vinci console. Tracking was activated during all critical stages of the surgery.The transrectal ultrasound robot was easy to set up and use, adding 7 minutes (range 5 to 14) to the procedure. It did not require an assistant or additional control devices. Qualitative feedback was acquired from the surgeons, who found transrectal ultrasound useful in identifying the urethra while passing the dorsal venous complex suture, defining the prostate-bladder interface during bladder neck dissection, identifying the seminal vesicles and their location with respect to the rectal wall, and identifying the distal prostate boundary at the apex.Real-time, registered robotic transrectal ultrasound guidance with automatic instrument tracking during robot-assisted laparoscopic radical prostatectomy is feasible and potentially useful. The results justify further studies to establish whether the approach can improve procedure outcomes.