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Lafond M, Payne A, Lafon C. Therapeutic ultrasound transducer technology and monitoring techniques: a review with clinical examples. Int J Hyperthermia 2024; 41:2389288. [PMID: 39134055 PMCID: PMC11375802 DOI: 10.1080/02656736.2024.2389288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 07/02/2024] [Accepted: 08/01/2024] [Indexed: 09/07/2024] Open
Abstract
The exponential growth of therapeutic ultrasound applications demonstrates the power of the technology to leverage the combinations of transducer technology and treatment monitoring techniques to effectively control the preferred bioeffect to elicit the desired clinical effect.Objective: This review provides an overview of the most commonly used bioeffects in therapeutic ultrasound and describes existing transducer technologies and monitoring techniques to ensure treatment safety and efficacy.Methods and materials: Literature reviews were conducted to identify key choices that essential in terms of transducer design, treatment parameters and procedure monitoring for therapeutic ultrasound applications. Effective combinations of these options are illustrated through descriptions of several clinical indications, including uterine fibroids, prostate disease, liver cancer, and brain cancer, that have been successful in leveraging therapeutic ultrasound to provide effective patient treatments.Results: Despite technological constraints, there are multiple ways to achieve a desired bioeffect with therapeutic ultrasound in a target tissue. Visualizations of the interplay of monitoring modality, bioeffect, and applied acoustic parameters are presented that demonstrate the interconnectedness of the field of therapeutic ultrasound. While the clinical indications explored in this review are at different points in the clinical evaluation path, based on the ever expanding research being conducted in preclinical realms, it is clear that additional clinical applications of therapeutic ultrasound that utilize a myriad of bioeffects will continue to grow and improve in the coming years.Conclusions: Therapeutic ultrasound will continue to improve in the next decades as the combination of transducer technology and treatment monitoring techniques will continue to evolve and be translated in clinical settings, leading to more personalized and efficient therapeutic ultrasound mediated therapies.
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Affiliation(s)
- Maxime Lafond
- LabTAU, INSERM, Centre Léon Bérard, Université, Lyon, France
| | - Allison Payne
- Department of Radiology and Imaging Sciences, University of UT, Salt Lake City, UT, USA
| | - Cyril Lafon
- LabTAU, INSERM, Centre Léon Bérard, Université, Lyon, France
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Filippou A, Georgiou A, Nikolaou A, Evripidou N, Damianou C. Advanced software for MRgFUS treatment planning. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 240:107726. [PMID: 37480647 DOI: 10.1016/j.cmpb.2023.107726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 07/18/2023] [Accepted: 07/18/2023] [Indexed: 07/24/2023]
Abstract
BACKGROUND AND OBJECTIVES Herein, a user-friendly software platform for 3-dimensional Focused Ultrasound treatment planning based on Magnetic Resonance Imaging (MRI) images is presented. METHODS The software directly retrieves and loads MRI images. Various design tools can be used on the MRI images to define the treatment area and the sonication parameters. Based on the treatment plan, the software controls the robotic motion and motion pattern of Magnetic Resonance guided Focused Ultrasound (MRgFUS) robotic systems to execute the treatment procedure. Real-time treatment monitoring is achieved through MRI images and thermometry. The software's functionality and performance were evaluated in both laboratory and MRI environments. Different treatment plans were designed on MRI images and sonications were executed on agar-based phantoms and polymer films. RESULTS Magnetic Resonance (MR) thermometry maps were acquired in the agar-based phantoms. An exceptional agreement was observed between the software-planned treatment area and the lesions produced on the polymer films. CONCLUSIONS The developed software was successfully integrated with the MRI and robotic system controls for performing accurate treatment planning and real-time monitoring during sonications. The software provides an extremely user-friendly interface, while in the future it could be enhanced by providing dynamic modulation of the ultrasonic parameters during the treatment process.
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Affiliation(s)
- Antria Filippou
- Cyprus University of Technology, Department of Electrical Engineering, Computer Engineering, and Informatics, 30 Archbishop Kyprianou Str., Limassol 3036, Cyprus.
| | - Andreas Georgiou
- Cyprus University of Technology, Department of Electrical Engineering, Computer Engineering, and Informatics, 30 Archbishop Kyprianou Str., Limassol 3036, Cyprus
| | - Anastasia Nikolaou
- Cyprus University of Technology, Department of Electrical Engineering, Computer Engineering, and Informatics, 30 Archbishop Kyprianou Str., Limassol 3036, Cyprus.
| | - Nikolas Evripidou
- Cyprus University of Technology, Department of Electrical Engineering, Computer Engineering, and Informatics, 30 Archbishop Kyprianou Str., Limassol 3036, Cyprus.
| | - Christakis Damianou
- Cyprus University of Technology, Department of Electrical Engineering, Computer Engineering, and Informatics, 30 Archbishop Kyprianou Str., Limassol 3036, Cyprus.
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Fernandes MC, Yildirim O, Woo S, Vargas HA, Hricak H. The role of MRI in prostate cancer: current and future directions. MAGMA (NEW YORK, N.Y.) 2022; 35:503-521. [PMID: 35294642 PMCID: PMC9378354 DOI: 10.1007/s10334-022-01006-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 01/16/2022] [Accepted: 03/03/2022] [Indexed: 06/14/2023]
Abstract
There has been an increasing role of magnetic resonance imaging (MRI) in the management of prostate cancer. MRI already plays an essential role in the detection and staging, with the introduction of functional MRI sequences. Recent advancements in radiomics and artificial intelligence are being tested to potentially improve detection, assessment of aggressiveness, and provide usefulness as a prognostic marker. MRI can improve pretreatment risk stratification and therefore selection of and follow-up of patients for active surveillance. MRI can also assist in guiding targeted biopsy, treatment planning and follow-up after treatment to assess local recurrence. MRI has gained importance in the evaluation of metastatic disease with emerging technology including whole-body MRI and integrated positron emission tomography/MRI, allowing for not only better detection but also quantification. The main goal of this article is to review the most recent advances on MRI in prostate cancer and provide insights into its potential clinical roles from the radiologist's perspective. In each of the sections, specific roles of MRI tailored to each clinical setting are discussed along with its strengths and weakness including already established material related to MRI and the introduction of recent advancements on MRI.
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Affiliation(s)
- Maria Clara Fernandes
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, NY, 10065, USA
| | - Onur Yildirim
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, NY, 10065, USA
| | - Sungmin Woo
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, NY, 10065, USA.
| | - Hebert Alberto Vargas
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, NY, 10065, USA
| | - Hedvig Hricak
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, NY, 10065, USA
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Clinical Performance and Future Potential of Magnetic Resonance Thermometry in Hyperthermia. Cancers (Basel) 2020; 13:cancers13010031. [PMID: 33374176 PMCID: PMC7794787 DOI: 10.3390/cancers13010031] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Hyperthermia is a treatment for cancer patients, which consists of heating the body to 43 °C. The temperature during treatment is usually measured by placing temperature probes intraluminal or invasively. The only clinically used option to measure temperature distributions non-invasively and in 3D is by MR thermometry (MRT). However, in order to be able to replace conventional temperature probes, MRT needs to become more reliable. In this review paper, we propose standardized performance thresholds for MRT, based on our experience of treating nearly 4000 patients. We then review the literature to assess to what extent these requirements are already being met in the clinic today and identify common problems. Lastly, using pre-clinical results in the literature, we assess where the biggest potential is to solve the problems identified. We hope that by standardizing MRT parameters as well as highlighting current and promising developments, progress in the field will be accelerated. Abstract Hyperthermia treatments in the clinic rely on accurate temperature measurements to guide treatments and evaluate clinical outcome. Currently, magnetic resonance thermometry (MRT) is the only clinical option to non-invasively measure 3D temperature distributions. In this review, we evaluate the status quo and emerging approaches in this evolving technology for replacing conventional dosimetry based on intraluminal or invasively placed probes. First, we define standardized MRT performance thresholds, aiming at facilitating transparency in this field when comparing MR temperature mapping performance for the various scenarios that hyperthermia is currently applied in the clinic. This is based upon our clinical experience of treating nearly 4000 patients with superficial and deep hyperthermia. Second, we perform a systematic literature review, assessing MRT performance in (I) clinical and (II) pre-clinical papers. From (I) we identify the current clinical status of MRT, including the problems faced and from (II) we extract promising new techniques with the potential to accelerate progress. From (I) we found that the basic requirements for MRT during hyperthermia in the clinic are largely met for regions without motion, for example extremities. In more challenging regions (abdomen and thorax), progress has been stagnating after the clinical introduction of MRT-guided hyperthermia over 20 years ago. One clear difficulty for advancement is that performance is not or not uniformly reported, but also that studies often omit important details regarding their approach. Motion was found to be the common main issue hindering accurate MRT. Based on (II), we reported and highlighted promising developments to tackle the issues resulting from motion (directly or indirectly), including new developments as well as optimization of already existing strategies. Combined, these may have the potential to facilitate improvement in MRT in the form of more stable and reliable measurements via better stability and accuracy.
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Dubinsky TJ, Khokhlova TD, Khokhlova V, Schade GR. Histotripsy: The Next Generation of High-Intensity Focused Ultrasound for Focal Prostate Cancer Therapy. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2020; 39:1057-1067. [PMID: 31830312 DOI: 10.1002/jum.15191] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 11/12/2019] [Accepted: 11/17/2019] [Indexed: 05/28/2023]
Abstract
This article reviews the most current methods and technological aspects of high-intensity focused ultrasound (HIFU), which is termed histotripsy. The rationale for focal therapy for prostate carcinoma rather than prostatectomy, which is being used extensively throughout Europe and Asia, is presented, and an argument for why HIFU is the modality of choice for primary therapy and recurrent disease is offered. The article presents a review of the technical advances including higher ultrasound beam energy than current thermal HIFU which allows for more accurate tissue targeting, less collateral tissue damage, and faster treatment times. Finally, the article presents a discussion about the advantage of ultrasound guidance for histotripsy in preference to magnetic resonance imaging guidance primarily based on cost, ease of application, and portability.
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Affiliation(s)
- Theodore J Dubinsky
- Department of Radiology, University of Washington, Seattle, Washington, USA
- Department of Obstetrics and Gynecology, University of Washington, Seattle, Washington, USA
| | - Tanya D Khokhlova
- Department of Medicine, University of Washington, Seattle, Washington, USA
- Department of Gastroenterology, University of Washington, Seattle, Washington, USA
| | - Vera Khokhlova
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA
- Department of Acoustics, Physics Faculty, M. V. Lomonosov Moscow State University, Moscow, Russia
| | - George R Schade
- Department of Urology, University of Washington, Seattle, Washington, USA
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Anttinen M, Yli-Pietilä E, Suomi V, Mäkelä P, Sainio T, Saunavaara J, Eklund L, Blanco Sequeiros R, Taimen P, Boström PJ. Histopathological evaluation of prostate specimens after thermal ablation may be confounded by the presence of thermally-fixed cells. Int J Hyperthermia 2020; 36:915-925. [PMID: 31466481 DOI: 10.1080/02656736.2019.1652773] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Purpose: Prostate cancer can be eradicated with heat exposure. However, high and rapid temperature elevations may cause thermofixation giving the appearance of viable tissue. The purpose was to characterize the immunoprofile and evaluate the viability of prostate regions with suspected thermofixation. Methods and materials: A prospective, ethics-approved and registered study (NCT03350529) enrolled six patients with MRI-visible, biopsy-concordant prostate cancer to undergo lesion-targeted MRI-guided transurethral ultrasound ablation (TULSA) followed by radical prostatectomy at 3 weeks, to evaluate the accuracy and efficacy of TULSA with whole-mount histology as a reference standard. If ambiguity about complete necrosis within the ablated region remained after hematoxylin-eosin staining, viability was assessed by immunohistochemistry. Treatment day MRI-thermometry and 3-week contrast-enhanced MRI post-TULSA were examined to assess ablation success and correlation with histopathology. Results: One patient presented with an apparently viable subregion inside the ablated area, surrounded by necrosis on H&E staining, located where temperature was highest on MRI-thermometry and tissues completely devascularized on MRI. Immunoprofile of the apparently viable tissue revealed changes in staining patterns suggesting thermofixation; the most significant evidence was the negative cytokeratin 8 staining detected with Cam5.2 antibody. A comprehensive literature review supports these observations of thermofixation with similar findings in prostate and other tissues. Conclusion: Thermally-fixed cells can sustain morphology on H&E staining. Misinterpretation of treatment failure may occur, if this phenomenon is not recognized and immunohistochemistry performed. Based on the previous literature and the current study, Cam5.2 staining for cytokeratin 8 appears to be a practical and reliable tool for distinguishing thermally-fixed from viable cells.
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Affiliation(s)
- Mikael Anttinen
- Department of Urology, Turku University Hospital , Turku , Finland
| | | | - Visa Suomi
- Department of Diagnostic Radiology, University of Turku , Turku , Finland.,Medical Imaging Centre of Southwest Finland, Turku University Hospital , Turku , Finland
| | - Pietari Mäkelä
- Department of Diagnostic Radiology, University of Turku , Turku , Finland
| | - Teija Sainio
- Department of Diagnostic Radiology, University of Turku , Turku , Finland
| | - Jani Saunavaara
- Department of Diagnostic Radiology, University of Turku , Turku , Finland
| | - Lauri Eklund
- Medical Imaging Centre of Southwest Finland, Turku University Hospital , Turku , Finland.,Institute of Biomedicine, University of Turku , Turku , Finland.,Department of Pathology, Turku University Hospital , Turku , Finland
| | | | - Pekka Taimen
- Institute of Biomedicine, University of Turku , Turku , Finland.,Department of Pathology, Turku University Hospital , Turku , Finland
| | - Peter J Boström
- Department of Urology, Turku University Hospital , Turku , Finland
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Odéen H, Parker DL. Magnetic resonance thermometry and its biological applications - Physical principles and practical considerations. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 110:34-61. [PMID: 30803693 PMCID: PMC6662927 DOI: 10.1016/j.pnmrs.2019.01.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 01/23/2019] [Indexed: 05/25/2023]
Abstract
Most parameters that influence the magnetic resonance imaging (MRI) signal experience a temperature dependence. The fact that MRI can be used for non-invasive measurements of temperature and temperature change deep inside the human body has been known for over 30 years. Today, MR temperature imaging is widely used to monitor and evaluate thermal therapies such as radio frequency, microwave, laser, and focused ultrasound therapy. In this paper we cover the physical principles underlying the biological applications of MR temperature imaging and discuss practical considerations and remaining challenges. For biological tissue, the MR signal of interest comes mostly from hydrogen protons of water molecules but also from protons in, e.g., adipose tissue and various metabolites. Most of the discussed methods, such as those using the proton resonance frequency (PRF) shift, T1, T2, and diffusion only measure temperature change, but measurements of absolute temperatures are also possible using spectroscopic imaging methods (taking advantage of various metabolite signals as internal references) or various types of contrast agents. Currently, the PRF method is the most used clinically due to good sensitivity, excellent linearity with temperature, and because it is largely independent of tissue type. Because the PRF method does not work in adipose tissues, T1- and T2-based methods have recently gained interest for monitoring temperature change in areas with high fat content such as the breast and abdomen. Absolute temperature measurement methods using spectroscopic imaging and contrast agents often offer too low spatial and temporal resolution for accurate monitoring of ablative thermal procedures, but have shown great promise in monitoring the slower and usually less spatially localized temperature change observed during hyperthermia procedures. Much of the current research effort for ablative procedures is aimed at providing faster measurements, larger field-of-view coverage, simultaneous monitoring in aqueous and adipose tissues, and more motion-insensitive acquisitions for better precision measurements in organs such as the heart, liver, and kidneys. For hyperthermia applications, larger coverage, motion insensitivity, and simultaneous aqueous and adipose monitoring are also important, but great effort is also aimed at solving the problem of long-term field drift which gets interpreted as temperature change when using the PRF method.
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Affiliation(s)
- Henrik Odéen
- University of Utah, Utah Center for Advanced Imaging Research, Department of Radiology and Imaging Sciences, 729 Arapeen Drive, Salt Lake City, UT 84108-1217, USA.
| | - Dennis L Parker
- University of Utah, Utah Center for Advanced Imaging Research, Department of Radiology and Imaging Sciences, 729 Arapeen Drive, Salt Lake City, UT 84108-1217, USA.
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Curto S, Faridi P, Shrestha TB, Pyle M, Maurmann L, Troyer D, Bossmann SH, Prakash P. An integrated platform for small-animal hyperthermia investigations under ultra-high-field MRI guidance. Int J Hyperthermia 2017; 34:341-351. [PMID: 28728442 DOI: 10.1080/02656736.2017.1339126] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
PURPOSE Integrating small-animal experimental hyperthermia instrumentation with magnetic resonance imaging (MRI) affords real-time monitoring of spatial temperature profiles. This study reports on the development and preliminary in vivo characterisation of a 2.45 GHz microwave hyperthermia system for pre-clinical small animal investigations, integrated within a 14 T ultra-high-field MRI scanner. MATERIALS AND METHODS The presented system incorporates a 3.5 mm (OD) directional microwave hyperthermia antenna, positioned adjacent to the small-animal target, radiating microwave energy for localised heating of subcutaneous tumours. The applicator is integrated within the 30 mm bore of the MRI system. 3D electromagnetic and biothermal simulations were implemented to characterise hyperthermia profiles from the directional microwave antenna. Experiments in tissue mimicking phantoms were performed to assess hyperthermia profiles and validate MR thermometry against fibre-optic temperature measurements. The feasibility of delivering in vivo hyperthermia exposures to subcutaneous 4T1 tumours in experimental mice under simultaneous MR thermometry guidance was assessed. RESULTS Simulations and experiments in tissue mimicking phantoms demonstrated the feasibility of heating 21-982 mm3 targets with 8-12 W input power. Minimal susceptibility and electrical artefacts introduced by the hyperthermia applicator were observed on MR imaging. MR thermometry was in excellent agreement with fibre-optic temperatures measurements (max. discrepancy ≤0.6 °C). Heating experiments with the reported system demonstrated the feasibility of heating subcutaneous tumours in vivo with simultaneous MR thermometry. CONCLUSIONS A platform for small-animal hyperthermia investigations under ultra-high-field MR thermometry was developed and applied to heating subcutaneous tumours in vivo.
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Affiliation(s)
- Sergio Curto
- a Department of Electrical and Computer Engineering , Kansas State University , Manhattan , KS , USA
| | - Pegah Faridi
- a Department of Electrical and Computer Engineering , Kansas State University , Manhattan , KS , USA
| | - Tej B Shrestha
- b Department of Anatomy and Physiology , Kansas State University , Manhattan , KS , USA
| | - Marla Pyle
- b Department of Anatomy and Physiology , Kansas State University , Manhattan , KS , USA
| | - Leila Maurmann
- c Department of Chemistry , Kansas State University , Manhattan , KS , USA
| | - Deryl Troyer
- b Department of Anatomy and Physiology , Kansas State University , Manhattan , KS , USA
| | - Stefan H Bossmann
- c Department of Chemistry , Kansas State University , Manhattan , KS , USA
| | - Punit Prakash
- a Department of Electrical and Computer Engineering , Kansas State University , Manhattan , KS , USA
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Toupin S, Bour P, Lepetit-Coiffé M, Ozenne V, Denis de Senneville B, Schneider R, Vaussy A, Chaumeil A, Cochet H, Sacher F, Jaïs P, Quesson B. Feasibility of real-time MR thermal dose mapping for predicting radiofrequency ablation outcome in the myocardium in vivo. J Cardiovasc Magn Reson 2017; 19:14. [PMID: 28143574 PMCID: PMC5286737 DOI: 10.1186/s12968-017-0323-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 01/10/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Clinical treatment of cardiac arrhythmia by radiofrequency ablation (RFA) currently lacks quantitative and precise visualization of lesion formation in the myocardium during the procedure. This study aims at evaluating thermal dose (TD) imaging obtained from real-time magnetic resonance (MR) thermometry on the heart as a relevant indicator of the thermal lesion extent. METHODS MR temperature mapping based on the Proton Resonance Frequency Shift (PRFS) method was performed at 1.5 T on the heart, with 4 to 5 slices acquired per heartbeat. Respiratory motion was compensated using navigator-based slice tracking. Residual in-plane motion and related magnetic susceptibility artifacts were corrected online. The standard deviation of temperature was measured on healthy volunteers (N = 5) in both ventricles. On animals, the MR-compatible catheter was positioned and visualized in the left ventricle (LV) using a bSSFP pulse sequence with active catheter tracking. Twelve MR-guided RFA were performed on three sheep in vivo at various locations in left ventricle (LV). The dimensions of the thermal lesions measured on thermal dose images, on 3D T1-weighted (T1-w) images acquired immediately after the ablation and at gross pathology were correlated. RESULTS MR thermometry uncertainty was 1.5 °C on average over more than 96% of the pixels covering the left and right ventricles, on each volunteer. On animals, catheter repositioning in the LV with active slice tracking was successfully performed and each ablation could be monitored in real-time by MR thermometry and thermal dosimetry. Thermal lesion dimensions on TD maps were found to be highly correlated with those observed on post-ablation T1-w images (R = 0.87) that also correlated (R = 0.89) with measurements at gross pathology. CONCLUSIONS Quantitative TD mapping from real-time rapid CMR thermometry during catheter-based RFA is feasible. It provides a direct assessment of the lesion extent in the myocardium with precision in the range of one millimeter. Real-time MR thermometry and thermal dosimetry may improve safety and efficacy of the RFA procedure by offering a reliable indicator of therapy outcome during the procedure.
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Affiliation(s)
- Solenn Toupin
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux University, F-33600 Pessac-Bordeaux, France
- Centre de recherche Cardio-Thoracique de Bordeaux, INSERM, U1045, F-33000 Bordeaux, France
- Siemens Healthineers France, F-93210 Saint-Denis, France
| | - Pierre Bour
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux University, F-33600 Pessac-Bordeaux, France
- Centre de recherche Cardio-Thoracique de Bordeaux, INSERM, U1045, F-33000 Bordeaux, France
- Image Guided Therapy, F-33600 Pessac, France
| | | | - Valéry Ozenne
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux University, F-33600 Pessac-Bordeaux, France
- Centre de recherche Cardio-Thoracique de Bordeaux, INSERM, U1045, F-33000 Bordeaux, France
| | | | | | - Alexis Vaussy
- Siemens Healthineers France, F-93210 Saint-Denis, France
| | - Arnaud Chaumeil
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux University, F-33600 Pessac-Bordeaux, France
- Centre de recherche Cardio-Thoracique de Bordeaux, INSERM, U1045, F-33000 Bordeaux, France
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), F-33600 Pessac, France
| | - Hubert Cochet
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux University, F-33600 Pessac-Bordeaux, France
- Centre de recherche Cardio-Thoracique de Bordeaux, INSERM, U1045, F-33000 Bordeaux, France
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), F-33600 Pessac, France
| | - Frédéric Sacher
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux University, F-33600 Pessac-Bordeaux, France
- Centre de recherche Cardio-Thoracique de Bordeaux, INSERM, U1045, F-33000 Bordeaux, France
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), F-33600 Pessac, France
| | - Pierre Jaïs
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux University, F-33600 Pessac-Bordeaux, France
- Centre de recherche Cardio-Thoracique de Bordeaux, INSERM, U1045, F-33000 Bordeaux, France
- Electrophysiology and Ablation Unit, Bordeaux University Hospital (CHU), F-33600 Pessac, France
| | - Bruno Quesson
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux University, F-33600 Pessac-Bordeaux, France
- Centre de recherche Cardio-Thoracique de Bordeaux, INSERM, U1045, F-33000 Bordeaux, France
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Toupin S, de Senneville BD, Ozenne V, Bour P, Lepetit-Coiffe M, Boissenin M, Jais P, Quesson B. Combination of principal component analysis and optical-flow motion compensation for improved cardiac MR thermometry. Phys Med Biol 2017; 62:1208-1224. [PMID: 28114116 DOI: 10.1088/1361-6560/aa51f9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The use of magnetic resonance (MR) thermometry for the monitoring of thermal ablation is rapidly expanding. However, this technique remains challenging for the monitoring of the treatment of cardiac arrhythmia by radiofrequency ablation due to the heart displacement with respiration and contraction. Recent studies have addressed this problem by compensating in-plane motion in real-time with optical-flow based tracking technique. However, these algorithms are sensitive to local variation of signal intensity on magnitude images associated with tissue heating. In this study, an optical-flow algorithm was combined with a principal component analysis method to reduce the impact of such effects. The proposed method was integrated to a fully automatic cardiac MR thermometry pipeline, compatible with a future clinical workflow. It was evaluated on nine healthy volunteers under free breathing conditions, on a phantom and in vivo on the left ventricle of a sheep. The results showed that local intensity changes in magnitude images had lower impact on motion estimation with the proposed method. Using this strategy, the temperature mapping accuracy was significantly improved.
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Affiliation(s)
- S Toupin
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Foundation Bordeaux University, F-33600 Pessac-Bordeaux, France. INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, U1045, F-33000 Bordeaux, France. Siemens Healthineers France, F-93210 Saint-Denis, France
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Ramsay E, Mougenot C, Staruch R, Boyes A, Kazem M, Bronskill M, Foster H, Sugar L, Haider M, Klotz L, Chopra R. Evaluation of Focal Ablation of Magnetic Resonance Imaging Defined Prostate Cancer Using Magnetic Resonance Imaging Controlled Transurethral Ultrasound Therapy with Prostatectomy as the Reference Standard. J Urol 2016; 197:255-261. [PMID: 27545572 DOI: 10.1016/j.juro.2016.06.100] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2016] [Indexed: 01/02/2023]
Abstract
PURPOSE We evaluated magnetic resonance imaging controlled transurethral ultrasound therapy as a treatment for magnetic resonance imaging defined focal prostate cancer using subsequent prostatectomy and histology as the reference standard. MATERIALS AND METHODS Five men completed this pilot study, which was approved by the institutional review board. Prior to radical prostatectomy focal tumors identified by magnetic resonance imaging were treated by coagulating targeted subtotal 3-dimensional volumes of prostate tissue using magnetic resonance imaging controlled transurethral focused ultrasound. Treatment was performed with a 3 Tesla clinical magnetic resonance imaging unit combined with modified clinical planning software for high intensity focused ultrasound therapy. After prostatectomy whole mount histological sections parallel to the magnetic resonance imaging treatment planes were used to compare magnetic resonance imaging measurements with thermal damage at the cellular level and, thus, evaluate treatment and target accuracy. RESULTS Three-dimensional target volumes of 4 to 20 cc and with radii up to 35 mm from the urethra were treated successfully. Mean ± SD temperature control accuracy at the target boundary was -1.6 ± 4.8C and the mean spatial targeting accuracy achieved was -1.5 ± 2.8 mm. Mean treatment accuracy with respect to histology was -0.4 ± 1.7 mm with all index tumors falling inside the histological outer limit of thermal injury. CONCLUSIONS Magnetic resonance imaging guided transurethral ultrasound therapy is capable of generating thermal coagulation and tumor destruction in targeted 3-dimensional angular sectors out to the prostate capsule for prostate glands up to 70 cc in volume. Ultrasound parameters needed to achieve ablation at the prostate capsule were determined, providing a foundation for future studies.
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Affiliation(s)
- Elizabeth Ramsay
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | | | - Robert Staruch
- Philips Research North America, Cambridge, Massachusetts
| | - Aaron Boyes
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Mohammad Kazem
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Michael Bronskill
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Harry Foster
- Department of Anaesthesiology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto
| | - Linda Sugar
- Department of Anatomic Pathology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Masoom Haider
- Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Laurence Klotz
- Department of Urology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Rajiv Chopra
- Department of Radiology and Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas.
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12
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Borman PTS, Bos C, de Boorder T, Raaymakers BW, Moonen CTW, Crijns SPM. Towards real-time thermometry using simultaneous multislice MRI. Phys Med Biol 2016; 61:N461-77. [DOI: 10.1088/0031-9155/61/17/n461] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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13
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Mougenot C, Pichardo S, Engler S, Waspe A, Colas EC, Drake JM. A rapid magnetic resonance acoustic radiation force imaging sequence for ultrasonic refocusing. Phys Med Biol 2016; 61:5724-40. [PMID: 27401452 DOI: 10.1088/0031-9155/61/15/5724] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Magnetic resonance guided acoustic radiation force imaging (MR-ARFI) is being used to correct for aberrations induced by tissue heterogeneities when using high intensity focusing ultrasound (HIFU). A compromise between published MR-ARFI adaptive solutions is proposed to achieve efficient refocusing of the ultrasound beam in under 10 min. In addition, an ARFI sequence based on an EPI gradient echo sequence was used to simultaneously monitor displacement and temperature with a large SNR and low distortion. This study was conducted inside an Achieva 3T clinical MRI using a Philips Sonalleve MR-HIFU system to emit a 1 ms pulsed sonication with duty cycle of 2.3% at 300 Wac inside a polymer phantom. Virtual elements defined by a Hadamard array with sonication patterns composed of 6 phase steps were used to characterize 64 groups of 4 elements to find the optimal phase of the 256 elements of the transducer. The 384 sonication patterns were acquired in 580 s to identify the set of phases that maximize the displacement at the focal point. Three aberrators (neonatal skull, 8 year old skull and a checkered pattern) were added to each sonication pattern to evaluate the performance of this refocusing algorithm (n = 4). These aberrators reduced the relative intensities to 95.3%, 69.6% and 25.5% for the neonatal skull, 8 year old skull, and checkered pattern virtual aberrators respectively. Using a 10 min refocusing algorithm, relative intensities of 101.6%, 91.3% and 93.3% were obtained. Better relative intensities of 103.9%, 94.3% and 101% were achieved using a 25 min refocusing algorithm. An average temperature increase of 4.2 °C per refocusing test was induced for the 10 min refocusing algorithm, resulting in a negligible thermal dose of 2 EM. A rapid refocusing of the beam can be achieved while keeping thermal effects to a minimum.
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Hartmann J, Gellermann J, Brandt T, Schmidt M, Pyatykh S, Hesser J, Ott O, Fietkau R, Bert C. Optimization of Single Voxel MR Spectroscopy Sequence Parameters and Data Analysis Methods for Thermometry in Deep Hyperthermia Treatments. Technol Cancer Res Treat 2016; 16:470-481. [PMID: 27422012 DOI: 10.1177/1533034616656310] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE The difference in the resonance frequency of water and methylene moieties of lipids quantifies in magnetic resonance spectroscopy the absolute temperature using a predefined calibration curve. The purpose of this study was the investigation of peak evaluation methods and the magnetic resonance spectroscopy sequence (point-resolved spectroscopy) parameter optimization that enables thermometry during deep hyperthermia treatments. MATERIALS AND METHODS Different Lorentz peak-fitting methods and a peak finding method using singular value decomposition of a Hankel matrix were compared. Phantom measurements on organic substances (mayonnaise and pork) were performed inside the hyperthermia 1.5-T magnetic resonance imaging system for the parameter optimization study. Parameter settings such as voxel size, echo time, and flip angle were varied and investigated. RESULTS Usually all peak analyzing methods were applicable. Lorentz peak-fitting method in MATLAB proved to be the most stable regardless of the number of fitted peaks, yet the slowest method. The examinations yielded an optimal parameter combination of 8 cm3 voxel volume, 55 millisecond echo time, and a 90° excitation pulse flip angle. CONCLUSION The Lorentz peak-fitting method in MATLAB was the most reliable peak analyzing method. Measurements in homogeneous and heterogeneous phantoms resulted in optimized parameters for the magnetic resonance spectroscopy sequence for thermometry.
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Affiliation(s)
- J Hartmann
- 1 Department of Radiation Oncology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - J Gellermann
- 2 Department of Radiation Oncology, University Hospital Tübingen, Tübingen, Germany.,3 Praxis/Zentrum für Strahlentherapie und Radioonkologie, Berlin, Germany
| | - T Brandt
- 1 Department of Radiation Oncology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - M Schmidt
- 1 Department of Radiation Oncology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - S Pyatykh
- 4 Medical Faculty Mannheim, Experimental Radiation Oncology, Heidelberg University, Mannheim, Germany
| | - J Hesser
- 4 Medical Faculty Mannheim, Experimental Radiation Oncology, Heidelberg University, Mannheim, Germany
| | - O Ott
- 1 Department of Radiation Oncology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - R Fietkau
- 1 Department of Radiation Oncology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - C Bert
- 1 Department of Radiation Oncology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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15
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Bing C, Staruch RM, Tillander M, Köhler MO, Mougenot C, Ylihautala M, Laetsch TW, Chopra R. Drift correction for accurate PRF-shift MR thermometry during mild hyperthermia treatments with MR-HIFU. Int J Hyperthermia 2016; 32:673-87. [PMID: 27210733 DOI: 10.1080/02656736.2016.1179799] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
UNLABELLED There is growing interest in performing hyperthermia treatments with clinical magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU) therapy systems designed for tissue ablation. During hyperthermia treatment, however, due to the narrow therapeutic window (41-45 °C), careful evaluation of the accuracy of proton resonant frequency (PRF) shift MR thermometry for these types of exposures is required. PURPOSE The purpose of this study was to evaluate the accuracy of MR thermometry using a clinical MR-HIFU system equipped with a hyperthermia treatment algorithm. METHODS Mild heating was performed in a tissue-mimicking phantom with implanted temperature sensors using the clinical MR-HIFU system. The influence of image-acquisition settings and post-acquisition correction algorithms on the accuracy of temperature measurements was investigated. The ability to achieve uniform heating for up to 40 min was evaluated in rabbit experiments. RESULTS Automatic centre-frequency adjustments prior to image-acquisition corrected the image-shifts in the order of 0.1 mm/min. Zero- and first-order phase variations were observed over time, supporting the use of a combined drift correction algorithm. The temperature accuracy achieved using both centre-frequency adjustment and the combined drift correction algorithm was 0.57° ± 0.58 °C in the heated region and 0.54° ± 0.42 °C in the unheated region. CONCLUSION Accurate temperature monitoring of hyperthermia exposures using PRF shift MR thermometry is possible through careful implementation of image-acquisition settings and drift correction algorithms. For the evaluated clinical MR-HIFU system, centre-frequency adjustment eliminated image shifts, and a combined drift correction algorithm achieved temperature measurements with an acceptable accuracy for monitoring and controlling hyperthermia exposures.
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Affiliation(s)
- Chenchen Bing
- a Department of Radiology , University of Texas Southwestern Medical Center , Dallas , Texas , USA
| | - Robert M Staruch
- a Department of Radiology , University of Texas Southwestern Medical Center , Dallas , Texas , USA ;,c Clinical Sites Research Program, Philips Research , Cambridge , Massachusetts , USA
| | | | | | | | | | - Theodore W Laetsch
- f Department of Pediatrics , University of Texas Southwestern Medical Center , Dallas , Texas , USA ;,g Pauline Allen Gill Center for Cancer and Blood Disorders, Children's Health System of Texas , Dallas , Texas , USA
| | - Rajiv Chopra
- a Department of Radiology , University of Texas Southwestern Medical Center , Dallas , Texas , USA ;,b Advanced Imaging Research Center, University of Texas Southwestern Medical Center , Dallas , Texas , USA
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Tatebe K, Ramsay E, Mougenot C, Kazem M, Peikari H, Bronskill M, Chopra R. Influence of geometric and material properties on artifacts generated by interventional MRI devices: Relevance to PRF-shift thermometry. Med Phys 2016; 43:241. [PMID: 26745917 DOI: 10.1118/1.4938099] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
PURPOSE Magnetic resonance imaging (MRI) is capable of providing valuable real-time feedback during medical procedures, partly due to the excellent soft-tissue contrast available. Several technical hurdles still exist to seamless integration of medical devices with MRI due to incompatibility of most conventional devices with this imaging modality. In this study, the effect of local perturbations in the magnetic field caused by the magnetization of medical devices was examined using finite element analysis modeling. As an example, the influence of the geometric and material characteristics of a transurethral high-intensity ultrasound applicator on temperature measurements using proton resonance frequency (PRF)-shift thermometry was investigated. METHODS The effect of local perturbations in the magnetic field, caused by the magnetization of medical device components, was examined using finite element analysis modeling. The thermometry artifact generated by a transurethral ultrasound applicator was simulated, and these results were validated against analytic models and scans of an applicator in a phantom. Several parameters were then varied to identify which most strongly impacted the level of simulated thermometry artifact, which varies as the applicator moves over the course of an ablative high-intensity ultrasound treatment. RESULTS Key design parameters identified as having a strong influence on the magnitude of thermometry artifact included the susceptibility of materials and their volume. The location of components was also important, particularly when positioned to maximize symmetry of the device. Finally, the location of component edges and the inclination of the device relative to the magnetic field were also found to be important factors. CONCLUSIONS Previous design strategies to minimize thermometry artifact were validated, and novel design strategies were identified that substantially reduce PRF-shift thermometry artifacts for a variety of device orientations. These new strategies are being incorporated into the next generation of applicators. The general strategy described in this study can be applied to the design of other interventional devices intended for use with MRI.
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Affiliation(s)
- Ken Tatebe
- Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390
| | - Elizabeth Ramsay
- Physical Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N3M5, Canada
| | - Charles Mougenot
- Philips Healthcare, 281 Hillmount Road, Markham, Ontario L6C 2S3, Canada
| | - Mohammad Kazem
- Physical Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N3M5, Canada
| | - Hamed Peikari
- Physical Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N3M5, Canada
| | - Michael Bronskill
- Physical Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N3M5, Canada and Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, Ontario M5G2M9, Canada
| | - Rajiv Chopra
- Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390; Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390; Physical Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N3M5, Canada; and Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, Ontario M5G2M9, Canada
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17
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Mougenot C, Waspe A, Looi T, Drake JM. Variable ultrasound trigger delay for improved magnetic resonance acoustic radiation force imaging. Phys Med Biol 2015; 61:712-27. [PMID: 26717008 DOI: 10.1088/0031-9155/61/2/712] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Magnetic resonance acoustic radiation force imaging (MR-ARFI) allows the quantification of microscopic displacements induced by ultrasound pulses, which are proportional to the local acoustic intensity. This study describes a new method to acquire MR-ARFI maps, which reduces the measurement noise in the quantification of displacement as well as improving its robustness in the presence of motion. Two MR-ARFI sequences were compared in this study. The first sequence 'variable MSG' involves switching the polarity of the motion sensitive gradient (MSG) between odd and even image frames. The second sequence named 'static MSG' involves a variable ultrasound trigger delay to sonicate during the first or second MSG for odd and even image frames, respectively. As previously published, the data acquired with a variable MSG required the use of reference data acquired prior to any sonication to process displacement maps. In contrary, data acquired with a static MSG were converted to displacement maps without using reference data acquired prior to the sonication. Displacement maps acquired with both sequences were compared by performing sonications for three different conditions: in a polyacrylamide phantom, in the leg muscle of a freely breathing pig and in the leg muscle of pig under apnea. The comparison of images acquired at even image frames and odd image frames indicates that the sequence with a static MSG provides a significantly better steady state (p < 0.001 based on a Student's t-test) than the images acquired with a variable MSG. In addition no reference data prior to sonication were required to process displacement maps for data acquired with a static MSG. The absence of reference data prior to sonication provided a 41% reduction of the spatial distribution of noise (p < 0.001 based on a Student's t-test) and reduced the sensitivity to motion for displacements acquired with a static MSG. No significant differences were expected and observed for thermal maps acquired with a variable MSG and a static MSG. The use of a static MSG with a variable ultrasound trigger delay improves the ARFI displacement map quality without additional acquisition time and remains compatible with the simultaneous acquisition of MR thermal maps.
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Affiliation(s)
- Charles Mougenot
- Philips Healthcare, 281 Hillmount Road, Markham, Ontario L6C 2S3, Canada
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18
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Schmitt A, Mougenot C, Chopra R. Spatiotemporal filtering of MR-temperature artifacts arising from bowel motion during transurethral MR-HIFU. Med Phys 2015; 41:113302. [PMID: 25370670 DOI: 10.1118/1.4897382] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE Transurethral MR-HIFU is a minimally invasive image-guided treatment for localized prostate cancer that enables precise targeting of tissue within the gland. The treatment is performed within a clinical MRI to obtain real-time MR thermometry used as an active feedback to control the spatial heating pattern in the prostate and to monitor for potential damage to surrounding tissues. This requires that the MR thermometry measurements are an accurate representation of the true tissue temperature. The proton resonance frequency shift thermometry method used is sensitive to tissue motion and changes in the local magnetic susceptibility that can be caused by the motion of air bubbles in the rectum, which can impact the performance of transurethral MR-HIFU in these regions of the gland. METHODS A method is proposed for filtering of temperature artifacts based on the temporal variance of the temperature, using empirical and dynamic positional knowledge of the ultrasonic heating beam, and an estimation of the measurement noise. A two-step correction strategy is introduced which eliminates artifact-detected temperature variations while keeping the noise level low through spatial averaging. RESULTS The filter has been evaluated by postprocessing data from five human transurethral ultrasound treatments. The two-step correction process led to reduced final temperature standard deviation in the prostate and rectum areas where the artifact was located, without negatively affecting areas distal to the artifact. The performance of the filter was also found to be consistent across all six of the data sets evaluated. The evaluation of the detection criterion parameter M determined that a value of M = 3 achieves a conservative filter with minimal loss of spatial resolution during the process. CONCLUSIONS The filter was able to remove most artifacts due to the presence of moving air bubbles in the rectum during transurethral MR-HIFU. A quantitative estimation of the filter capabilities shows a systematic improvement in the standard deviation of the corrected temperature maps in the rectum zone as well as in the entire acquired slice.
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Affiliation(s)
- Alain Schmitt
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada
| | - Charles Mougenot
- Philips Healthcare, 281 Hillmount Road, Markham, Ontario L6C 2S3, Canada
| | - Rajiv Chopra
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canadaand Department of Radiology, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9061
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Denis de Senneville B, El Hamidi A, Moonen C. A direct PCA-based approach for real-time description of physiological organ deformations. IEEE TRANSACTIONS ON MEDICAL IMAGING 2015; 34:974-982. [PMID: 25423649 DOI: 10.1109/tmi.2014.2371995] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Dynamic magnetic resonance (MR)-imaging can provide functional and positional information in real-time, which can be conveniently used online to control a cancer therapy, e.g., using high intensity focused ultrasound or radio therapy. However, a precise real-time correction for motion is fundamental in abdominal organs to ensure an optimal treatment dose associated with a limited toxicity in nearby organs at risk. This paper proposes a real-time direct principal component analysis (PCA)-based technique which offers a robust approach for motion estimation of abdominal organs and allows correcting motion related artifacts. The PCA was used to detect spatio-temporal coherences of the periodic organ motion in a learning step. During the interventional procedure, physiological contributions were characterized quantitatively using a small set of parameters. A coarse-to-fine resolution scheme is proposed to improve the stability of the algorithm and afford a predictable constant latency of 80 ms. The technique was evaluated on 12 free-breathing volunteers and provided an improved real-time description of motion related to both breathing and cardiac cycles. A reduced learning step of 10 s was sufficient without any need for patient-specific control parameters, rendering the method suitable for clinical use.
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Salgaonkar VA, Diederich CJ. Catheter-based ultrasound technology for image-guided thermal therapy: current technology and applications. Int J Hyperthermia 2015; 31:203-15. [PMID: 25799287 DOI: 10.3109/02656736.2015.1006269] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Catheter-based ultrasound (CBUS) is applied to deliver minimally invasive thermal therapy to solid cancer tumours, benign tissue growth, vascular disease, and tissue remodelling. Compared to other energy modalities used in catheter-based surgical interventions, unique features of ultrasound result in conformable and precise energy delivery with high selectivity, fast treatment times, and larger treatment volumes. We present a concise review of CBUS technology being currently utilized in animal and clinical studies or being developed for future applications. CBUS devices have been categorised into interstitial, endoluminal and endovascular/cardiac applications. Basic applicator designs, site-specific evaluations and possible treatment applications have been discussed in brief. Particular emphasis has been given to ablation studies that incorporate image guidance for applicator placement, therapy monitoring, feedback control, and post-procedure assessment. Examples of devices included here span the entire spectrum of the development cycle from preliminary simulation-based design studies to implementation in clinical investigations. The use of CBUS under image guidance has the potential for significantly improving precision and applicability of thermal therapy delivery.
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Affiliation(s)
- Vasant A Salgaonkar
- Department of Radiation Oncology, University of California , San Francisco, California , USA
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21
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Goharrizi AY, Kwong R, Chopra R. Development of robust/predictive control strategies for image-guided ablative treatments using a minimally invasive ultrasound applicator. Int J Hyperthermia 2014; 30:438-46. [PMID: 25314227 DOI: 10.3109/02656736.2014.963702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
PURPOSE One important challenge in image-guided ablative therapies is the effect of heat diffusion which can cause damage to surrounding organs and limit the ability to achieve a conformal pattern of thermal damage. Furthermore, tissue properties such as perfusion and energy absorption can be dynamic and difficult to measure. This paper attempts to address these problems by proposing new control methods. MATERIALS AND METHODS A novel predictive approach was developed to compensate for the effect of heat diffusion using a minimally invasive rotating ultrasound heating applicator for ablative therapy. This method can be merged into any closed-loop control strategy. A binary controller, a previously developed adaptive proportional-integral controller, and a model reference adaptive controller were employed and compared, all with the predictive element incorporated. The reason for choosing these controllers was that none of them needed a model of the tissue or exact values of their parameters. RESULTS The effectiveness of these controllers was demonstrated through both simulation and experimental studies. The results were consistent and demonstrated equivalent performance between controllers. CONCLUSIONS The dominant influence on radial targeting accuracy was the prediction element described in this paper. A binary controller with a predictive element may provide the best balance of performance and simplicity for this application.
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Ramsay E, Mougenot C, Kazem M, Laetsch TW, Chopra R. Temperature-dependent MR signals in cortical bone: potential for monitoring temperature changes during high-intensity focused ultrasound treatment in bone. Magn Reson Med 2014; 74:1095-102. [PMID: 25310966 DOI: 10.1002/mrm.25492] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 09/10/2014] [Accepted: 09/18/2014] [Indexed: 12/23/2022]
Abstract
PURPOSE Because existing magnetic resonance thermometry techniques do not provide temperature information within bone, high-intensity focused ultrasound (HIFU) exposures in bone are monitored using temperature changes in adjacent soft tissues. In this study, the potential to monitor temperature changes in cortical bone using a short TE gradient echo sequence is evaluated. METHODS The feasibility of this proposed method was initially evaluated by measuring the temperature dependence of the gradient echo signal during cooling of cortical bone samples implanted with fiber-optic temperature sensors. A subsequent experiment involved heating a cortical bone sample using a clinical MR-HIFU system. RESULTS A consistent relationship between temperature change and the change in magnitude signal was observed within and between cortical bone samples. For the two-dimensional gradient echo sequence implemented in this study, a least-squares linear fit determined the percentage change in signal to be (0.90 ± 0.01)%/°C. This relationship was used to estimate temperature changes observed in the HIFU experiment and these temperatures agreed well with those measured from an implanted fiber-optic sensor. CONCLUSION This method appears capable of displaying changes related to temperature in cortical bone and could improve the safety of MR-HIFU treatments. Further investigations into the sensitivity of the technique in vivo are warranted.
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Affiliation(s)
| | | | | | - Theodore W Laetsch
- Children's Medical Center, Dallas, Texas, USA
- University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Rajiv Chopra
- Sunnybrook Research Institute, Toronto, Canada
- University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
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Muller BG, van den Bos W, Brausi M, Cornud F, Gontero P, Kirkham A, Pinto PA, Polascik TJ, Rastinehad AR, de Reijke TM, de la Rosette JJ, Ukimura O, Villers A, Walz J, Wijkstra H, Marberger M. Role of multiparametric magnetic resonance imaging (MRI) in focal therapy for prostate cancer: a Delphi consensus project. BJU Int 2014; 114:698-707. [PMID: 24180365 DOI: 10.1111/bju.12548] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Berrend G. Muller
- Department of Urology; AMC University Hospital; Amsterdam The Netherlands
| | | | - Maurizio Brausi
- Department of Urology; EstenseS. Agostino Hospital; Modena Italy
| | | | - Paolo Gontero
- Department of Urology; Molinette University Hospital; Turin Italy
| | | | - Peter A. Pinto
- Department of Urology; National Cancer Institute; Bethesda MD
| | - Thomas J. Polascik
- Department of Surgery/Urology; Duke University Medical Center; Durham NC
| | | | - Theo M. de Reijke
- Department of Urology; AMC University Hospital; Amsterdam The Netherlands
| | | | - Osamu Ukimura
- Department of Urology; University of Southern California; Norris Cancer Center; Los Angeles CA USA
| | | | - Jochen Walz
- Department of Urology; Institut Paoli-Calmettes Cancer Center; Marseille France
| | - Hessel Wijkstra
- Department of Urology; AMC University Hospital; Amsterdam The Netherlands
- Department of Electrical Engineering; Eindhoven University of Technology; Eindhoven The Netherlands
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