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Hong L, Zhang W, Pan F, Xiaobo G, Huang H, You Y, Deng L, Wang Z, Zhang C. An in vitro and in vivo study on extracorporeal transducer optimization for high-intensity focused ultrasound to improve the safety and efficacy of breast tumor ablation. Int J Hyperthermia 2023; 40:2251734. [PMID: 37654021 DOI: 10.1080/02656736.2023.2251734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 07/24/2023] [Accepted: 08/19/2023] [Indexed: 09/02/2023] Open
Abstract
OBJECTIVE To observe the characteristics of a new extracorporeal high intensity focused ultrasound transducer, titled Haifu system JCQ-B, and to compare its safety and efficacy for breast ablation with the standard Haifu system JC transducer. MATERIALS AND METHODS Ox liver with pig skin and pork ribs were prepared in a semi-sphere shape, served as in vitro acoustic model. The udders of female goats were used as in vivo acoustic model. Both in vitro and in vivo models were ablated by either JCQ-B or JC transducer. The morphology of biological focal region (BFR), the coagulative necrosis volume, and the temperature increase were observed and compared. RESULTS The BFR morphology of JCQ-B transducer was circular both in vitro and in vivo, with a length-width ratio close to one. Under the same sonication parameters (sonication power, time and depth in tissue), coagulation necrosis volume caused by JCQ-B transducer was larger than that caused by JC transducer both in vitro and in vivo. The increase in temperature in the near and far acoustic pathways with JCQ-B transducer was significantly lower than that of JC transducer in vitro. After receiving high sonication energy during in vivo experimentation, there were no complications observed after the ablation of JCQ-B transducer, while small skin damage was observed after the ablation of JC transducer. CONCLUSIONS The JCQ-B transducer improved the safety and efficacy of treatment by optimizing BFR morphology and ablation efficiency, which could be applied in the treatment of breast tumor.
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Affiliation(s)
- Liu Hong
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
- Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
- National Engineering Research Center of Ultrasound Medicine, Chongqing, P.R. China
| | - Wendy Zhang
- Department of Radiology, Staten Island University Hospital, Staten Island, NY, USA
| | - Feibao Pan
- Department of Cerebrovascular Disease, Suining Central Hospital, Suining, P.R. China
| | - Gong Xiaobo
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
- Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
- National Engineering Research Center of Ultrasound Medicine, Chongqing, P.R. China
| | - Haoran Huang
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
- Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
- National Engineering Research Center of Ultrasound Medicine, Chongqing, P.R. China
- Chongqing Haifu Hospital, Chongqing, P.R. China
| | - Yaqing You
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
- Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
- National Engineering Research Center of Ultrasound Medicine, Chongqing, P.R. China
| | - Lulu Deng
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
- Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
- National Engineering Research Center of Ultrasound Medicine, Chongqing, P.R. China
| | - Zhibiao Wang
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
- Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
- Chongqing Haifu Hospital, Chongqing, P.R. China
| | - Cai Zhang
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
- Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing, P.R. China
- National Engineering Research Center of Ultrasound Medicine, Chongqing, P.R. China
- Chongqing Haifu Hospital, Chongqing, P.R. China
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Gonnah AR, Masoud O, AbdelWahab M, ElMosalamy A, Al-Naseem A. The Role of High Intensity Focused Ultrasound in the Treatment of Fibroadenomas: A Systematic Review. Breast Care (Basel) 2023; 18:279-288. [PMID: 37900548 PMCID: PMC10601662 DOI: 10.1159/000524738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 04/21/2022] [Indexed: 10/31/2023] Open
Abstract
Introduction Fibroadenomas are solid, mobile, and non-tender benign breast lumps, with highest prevalence amongst young women aged between 15 and 35. Symptoms can include discomfort, and they can become problematic, particularly when they enlarge, resulting in many referrals for biopsies, with fibroadenomas accounting for 30-75% of the cases. Diagnosis is based on triple assessment that involves a clinical examination, ultrasound imaging, and mammography, as well as core needle biopsies. Current management includes observation for 6-12 months, with the indication of definitive surgery, in cases that are older than 35 years or with fibroadenoma persistence. Serious adverse effects of surgery might include nipple areolar distortion, scarring, and damage to the breast tissue, as well as the risks associated with surgery and anesthesia, making it a non-feasible option. Methods A literature search was performed on the databases Embase, MEDLINE/PubMed, Google Scholar, and Ovid for English language papers published between January 1, 2000, and March 17, 2021. A structured protocol was employed to devise a comprehensive search strategy with keywords and Boolean operators defined by the research question. The keywords used for the search were "HIFU", "High Intensity Focused Ultrasound," "Fibroadenoma," "Breast," "Lesion." This review was carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results Recently, a thermal ablative technique, high intensity focused ultrasound (HIFU), was found to be a safe, noninvasive, and technically successful alternative, having displayed promising outcomes in reducing the volume of fibroadenomas, pain experienced by patients, and the length of hospitalization. Quality of life improvement was also evidenced, exhibited by the disappearance of symptoms, and enhanced physical activity post-intervention, in addition to patients' satisfaction with the cosmetic results and future recommendation of the procedure to other patients. Conclusion Overall, HIFU is a well-tolerated treatment associated, with low risk of complications, that can potentially include erythema, skin discoloration, and bruising with the majority of these self-resolving shortly after the procedure.
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Affiliation(s)
| | - Omar Masoud
- Faculty of Life Sciences and Medicine, King’s College London, London, UK
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Zimmerman BE, Johnson SL, Odéen HA, Shea JE, Factor RE, Joshi SC, Payne AH. Histology to 3D in vivo MR registration for volumetric evaluation of MRgFUS treatment assessment biomarkers. Sci Rep 2021; 11:18923. [PMID: 34556678 PMCID: PMC8460731 DOI: 10.1038/s41598-021-97309-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 08/24/2021] [Indexed: 11/09/2022] Open
Abstract
Advances in imaging and early cancer detection have increased interest in magnetic resonance (MR) guided focused ultrasound (MRgFUS) technologies for cancer treatment. MRgFUS ablation treatments could reduce surgical risks, preserve organ tissue and function, and improve patient quality of life. However, surgical resection and histological analysis remain the gold standard to assess cancer treatment response. For non-invasive ablation therapies such as MRgFUS, the treatment response must be determined through MR imaging biomarkers. However, current MR biomarkers are inconclusive and have not been rigorously evaluated against histology via accurate registration. Existing registration methods rely on anatomical features to directly register in vivo MR and histology. For MRgFUS applications in anatomies such as liver, kidney, or breast, anatomical features that are not caused by the treatment are often insufficient to drive direct registration. We present a novel MR to histology registration workflow that utilizes intermediate imaging and does not rely on anatomical MR features being visible in histology. The presented workflow yields an overall registration accuracy of 1.00 ± 0.13 mm. The developed registration pipeline is used to evaluate a common MRgFUS treatment assessment biomarker against histology. Evaluating MR biomarkers against histology using this registration pipeline will facilitate validating novel MRgFUS biomarkers to improve treatment assessment without surgical intervention. While the presented registration technique has been evaluated in a MRgFUS ablation treatment model, this technique could be potentially applied in any tissue to evaluate a variety of therapeutic options.
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Affiliation(s)
- Blake E Zimmerman
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA. .,Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, USA.
| | - Sara L Johnson
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA.,Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT, USA
| | - Henrik A Odéen
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT, USA
| | - Jill E Shea
- Department of Surgery, University of Utah, Salt Lake City, UT, USA
| | - Rachel E Factor
- Department of Pathology, University of Utah, Salt Lake City, UT, USA
| | - Sarang C Joshi
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA.,Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, USA
| | - Allison H Payne
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT, USA
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Sanchez M, Barrere V, Treilleux I, Chopin N, Melodelima D. Development of a noninvasive HIFU treatment for breast adenocarcinomas using a toroidal transducer based on preliminary attenuation measurements. ULTRASONICS 2021; 115:106459. [PMID: 33990009 DOI: 10.1016/j.ultras.2021.106459] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 01/21/2021] [Accepted: 05/04/2021] [Indexed: 06/12/2023]
Abstract
Breast cancer is the most commonly diagnosed type of cancer among women. For the last fifteen years, treatments that are less invasive than lumpectomy, such as high-intensity focused ultrasound (HIFU) therapy, have been developed, with encouraging results. In this study, a toroidal HIFU transducer was used to create lesions of at least 2 cm in diameter within less than one minute of treatment. The toroidal HIFU transducer created two focal zones that led to large, fast and homogeneous ablations (10.5 cc/min). The experiments were conducted in 30 human samples of normal breast tissues recovered from mastectomies to measure acoustic attenuation (N = 30), and then, HIFU lesions were created (N = 15). Eight HIFU ablations were performed to evaluate the reproducibility of the lesions. HIFU lesions were created in 45 s with a toroidal HIFU transducer working at 2.5 MHz. The longest and shortest axes of the HIFU lesions were 21.7 ± 3.1 mm and 23.5 ± 3.3 mm respectively, corresponding to an average volume of 7.3 ± 1.4 cm3. These HIFU lesions were performed at an average depth of 19.0 ± 1.5 mm, while the integrity of the skin was preserved. The HIFU-treated breast tissues had a higher level of attenuation (0.57 ± 0.11 Np.cm-1.MHz-1) when compared to the untreated tissues (0.21 ± 0.04 Np.cm-1.MHz-1). This study shows the feasibility of a fast and fully noninvasive treatment using a toroidal transducer for breast tumors measuring up to 15 mm in diameter.
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Affiliation(s)
- M Sanchez
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003 Lyon, France
| | - V Barrere
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003 Lyon, France
| | | | - N Chopin
- Centre Léon Bérard, F-69008 Lyon, France
| | - D Melodelima
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003 Lyon, France.
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McLean M, Parker DL, Odéen H, Payne A. A T1-based correction method for proton resonance frequency shift thermometry in breast tissue. Med Phys 2021; 48:4719-4729. [PMID: 34265109 DOI: 10.1002/mp.15085] [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] [Received: 10/28/2020] [Revised: 05/30/2021] [Accepted: 06/01/2021] [Indexed: 11/06/2022] Open
Abstract
PURPOSE Develop and evaluate the effectiveness of a T1-based correction method for errors in proton resonant frequency shift thermometry due to non-local field effects caused by heating in fatty breast tissues. METHODS Computational models of human breast tissue were created by segmenting MRI data from a healthy human volunteer. MR-guided focused ultrasound (MRgFUS) heating and MR thermometry measurements were simulated in several locations in the heterogeneous segmented breast models. A T1-based correction method for PRF thermometry errors was applied and the maximum positive and negative errors and the root mean squared error (RMSE) in a region around each heating location was evaluated with and without correction. The method uses T1 measurements to estimate the temperature change in fatty tissues and correct for their influence. Experimental data from a heating study in cadaver breast tissue were analyzed, and the expected PRFS error computed. RESULTS The simulated MR thermometry had maximum single voxel errors ranging between 10% and 18% when no correction was applied. Applying the correction led to a considerable improvement, lowering the maximum error range to 2%-5%. The 5th to 95th percentile interval of the temperature error distribution was also lowered with correction, from approximately 3.5 to 1°C. This correction worked even when T1 times were uniformly raised or lowered by 5%-10%. The experimental data showed predicted errors of 15%. CONCLUSIONS This simulation study demonstrates that the T1-based correction method reduces MR thermometry errors due to non-local effects from heating in fatty tissues, potentially improving the accuracy of thermometry measurements during MRgFUS treatments. The presented correction method is reliant on having a patient-specific 3D model of the breast, and may be limited by the accuracy of the fat temperatures which in turn may be limited by noise or bias present in the T1 measurements.
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Zimmerman BE, Johnson S, Odeen H, Shea J, Foote MD, Winkler N, Joshi SC, Payne A. Learning Multiparametric Biomarkers for Assessing MR-Guided Focused Ultrasound Treatment of Malignant Tumors. IEEE Trans Biomed Eng 2021; 68:1737-1747. [PMID: 32946378 PMCID: PMC7969473 DOI: 10.1109/tbme.2020.3024826] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Noninvasive MR-guided focused ultrasound (MRgFUS) treatments are promising alternatives to the surgical removal of malignant tumors. A significant challenge is assessing the viability of treated tissue during and immediately after MRgFUS procedures. Current clinical assessment uses the nonperfused volume (NPV) biomarker immediately after treatment from contrast-enhanced MRI. The NPV has variable accuracy, and the use of contrast agent prevents continuing MRgFUS treatment if tumor coverage is inadequate. This work presents a novel, noncontrast, learned multiparametric MR biomarker that can be used during treatment for intratreatment assessment, validated in a VX2 rabbit tumor model. A deep convolutional neural network was trained on noncontrast multiparametric MR images using the NPV biomarker from follow-up MR imaging (3-5 days after MRgFUS treatment) as the accurate label of nonviable tissue. A novel volume-conserving registration algorithm yielded a voxel-wise correlation between treatment and follow-up NPV, providing a rigorous validation of the biomarker. The learned noncontrast multiparametric MR biomarker predicted the follow-up NPV with an average DICE coefficient of 0.71, substantially outperforming the current clinical standard (DICE coefficient = 0.53). Noncontrast multiparametric MR imaging integrated with a deep convolutional neural network provides a more accurate prediction of MRgFUS treatment outcome than current contrast-based techniques.
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Payne A, Merrill R, Minalga E, Hadley JR, Odeen H, Hofstetter LW, Johnson S, Tunon de Lara C, Auriol S, Recco S, Dumont E, Parker DL, Palussiere J. A Breast-Specific MR Guided Focused Ultrasound Platform and Treatment Protocol: First-in-Human Technical Evaluation. IEEE Trans Biomed Eng 2021; 68:893-904. [PMID: 32784128 PMCID: PMC7878578 DOI: 10.1109/tbme.2020.3016206] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE This paper presents and evaluates a breast-specific magnetic resonance guided focused ultrasound (MRgFUS) system. A first-in-human evaluation demonstrates the novel hardware, a sophisticated tumor targeting algorithm and a volumetric magnetic resonance imaging (MRI) protocol. METHODS At the time of submission, N = 10 patients with non-palpable T0 stage breast cancer have been treated with the breast MRgFUS system. The described tumor targeting algorithm is evaluated both with a phantom test and in vivo during the breast MRgFUS treatments. Treatments were planned and monitored using volumetric MR-acoustic radiation force imaging (MR-ARFI) and temperature imaging (MRTI). RESULTS Successful technical treatments were achieved in 80 % of the patients. All patients underwent the treatment with no sedation and 60 % of participants had analgesic support. The total MR treatment time ranged from 73 to 114 minutes. Mean error between desired and achieved targeting in a phantom was 2.9 ±1.8 mm while 6.2 ±1.9 mm was achieved in patient studies, assessed either with MRTI or MR-ARFI measurements. MRTI and MR-ARFI were successful in 60 % and 70 % of patients, respectively. CONCLUSION The targeting accuracy allows the accurate placement of the focal spot using electronic steering capabilities of the transducer. The use of both volumetric MRTI and MR-ARFI provides complementary treatment planning and monitoring information during the treatment, allowing the treatment of all breast anatomies, including homogeneously fatty breasts.
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Kuo LW, Dong GC, Pan CC, Chen SF, Chen GS. An MRI-Guided Ring High-Intensity Focused Ultrasound System for Noninvasive Breast Ablation. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2020; 67:1839-1847. [PMID: 32386148 DOI: 10.1109/tuffc.2020.2992764] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
High-intensity focused ultrasound (HIFU) has been used for noninvasive treatment of breast tumors, but the present magnetic resonance imaging (MRI)-guided HIFU (MRI-HIFU) systems encounter skin burn. In this study, a novel MRI-HIFU breast ablation system was developed to improve the above problem. The system consisted of the ring HIFU phased-array transducer, a commercial power amplifier, the mechanical positioner, and the graphical user interface control software. MRI thermometry was also established to monitor the temperature in the HIFU-treated tissue. Ablation of pork and the in vivo rabbit leg were carried out to validate the developed system. Results of fat-surrounding pork ablation showed that the ring HIFU system reached a safe margin of 3 mm without fat burn. Moreover, precision of the positioner moving the HIFU focal zone was within 6% error under MRI circumstances. The representative MRI temperature images show that the peak temperatures among the five ablations ranged between 66 °C and 91 °C, and their thermal doses were over 10000. The system could also ablate the biceps femoris of a rabbit without skin burn to form a lesion of 2.5 mm beneath the skin. With the HIFU dose of 315 W/10 s, the MRI temperature map revealed that the maximum temperature and the thermal dose were 60 °C and 3380, respectively. The MRI-guided ring HIFU system can ablate the target tissue near subcutaneous fat without fat burn. The system prototype is a promising tool for clinical implementation.
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Wear KA, Howard SM. Correction for Spatial Averaging Artifacts in Hydrophone Measurements of High-Intensity Therapeutic Ultrasound: An Inverse Filter Approach. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2019; 66:1453-1464. [PMID: 31247548 PMCID: PMC6936621 DOI: 10.1109/tuffc.2019.2924351] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
High-intensity therapeutic ultrasound (HITU) pressure is often measured using a hydrophone. HITU pressure waves typically contain multiple harmonics due to nonlinear propagation. As harmonic frequency increases, harmonic beamwidth decreases. For sufficiently high harmonic frequency, beamwidth may become comparable to the hydrophone effective sensitive element diameter, resulting in signal reduction due to spatial averaging. An analytic formula for a hydrophone spatial averaging filter for beams with Gaussian harmonic radial profiles was tested on HITU pressure signals generated by three transducers (1.45 MHz, F/1; 1.53 MHz, F/1.5; 3.91 MHz, F/1) with focal pressures up to 48 MPa. The HITU signals were measured using fiber-optic and needle hydrophones (nominal geometrical sensitive element diameters: 100 and [Formula: see text]). Harmonic radial profiles were measured with transverse scans in the focal plane using the fiber-optic hydrophone. Harmonic radial profiles were accurately approximated by Gaussian functions with root-mean-square (rms) differences between transverse scans and Gaussian fits less than 9% for frequencies up to approximately 50 MHz. The Gaussian harmonic beamwidth parameter σn varied with harmonic number n according to a power law, σn = σ1/nq where . RMS differences between experimental and theoretical spatial averaging filters were 11% ± 1% (1.45 MHz), 8% ± 1% (1.53 MHz), and 4% ± 1% (3.91 MHz). For the two more highly focused (F/1) transducers, the effect of spatial averaging was to underestimate peak compressional pressure (pcp), peak rarefactional pressure (prp), and pulse intensity integral (pii) by (mean ± standard deviation) (pcp: 4.9% ± 0.5%, prp: 0.4% ± 0.2%, pii: 2.9% ± 1%) and (pcp: 28.3% ± 9.6%, prp: 6% ± 2.4%, pii: 24.3% ± 6.7%) for the 100- and 400- [Formula: see text]-diameter hydrophones, respectively. These errors can be suppressed by the application of the inverse spatial averaging filter.
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Svedin BT, Payne A, Parker DL. Simultaneous proton resonance frequency shift thermometry and T 1 measurements using a single reference variable flip angle T 1 method. Magn Reson Med 2019; 81:3138-3152. [PMID: 30652347 DOI: 10.1002/mrm.27643] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 11/20/2018] [Accepted: 11/29/2018] [Indexed: 12/31/2022]
Abstract
PURPOSE Implement simultaneous proton resonance frequency (PRF) shift and T1 measurements with equivalent temporal resolution using a single reference variable flip angle method. This novel method allows for simultaneous thermometry in both aqueous and fatty tissue. METHODS This method acquires a single reference image at the lower flip angle and all dynamic images at the higher angle. T1 is calculated using a single reference variable flip angle method, which accounts for the reference image temperature remaining constant. Monte Carlo simulations determined the optimal dynamic flip angle for combined PRF and T1 measurements. This method was evaluated in MR-guided focused ultrasound heating experiments using a gelatin phantom and human cadaver breasts. In vivo measurement precision was demonstrated in healthy female volunteers under nonheating conditions. RESULTS Temperature rise during MR-guided focused ultrasound heating was measured in aqueous tissue with both PRF and T1 . Both measures show good qualitative agreement in both space and time in aqueous tissue. The T1 change due to temperature increase was measured in fat, demonstrating the expected temporal response. The dynamic flip angle that produces optimal SNR for PRF measurements is lower than the optimal angle for T1 measurements, necessitating the selection of a compromise angle. CONCLUSION The single reference variable flip angle method provides a reliable way to simultaneously measure PRF temperature and T1 change and overcomes PRF's inability to simultaneously monitor temperature in aqueous and adipose tissues. Future work will calibrate T1 change to temperature, enabling real-time temperature in fat and increasing patient safety and treatment efficacy during thermal interventional treatments.
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Affiliation(s)
- Bryant T Svedin
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah
| | - Allison Payne
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah
| | - Dennis L Parker
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah
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11
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Svedin BT, Dillon CR, Parker DL. Effect of k-space-weighted image contrast and ultrasound focus size on the accuracy of proton resonance frequency thermometry. Magn Reson Med 2018; 81:247-257. [PMID: 30058224 DOI: 10.1002/mrm.27383] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 12/30/2022]
Abstract
PURPOSE To construct a predictive model that describes how the duration and symmetry of a k-space-weighted image contrast (KWIC) window affects the temporal resolution of differently sized ultrasound foci when using a pseudo-golden angle stack-of-stars acquisition. METHODS We performed a modulation analysis of proton resonance frequency temperature measurements to create the temporal modulation transfer function for KWIC windows of different symmetry and temporal duration. We reconstructed simulated ultrasound heating trajectories and stack-of-stars k-space data as well as experimental phantom data using the same trajectories. Images were reconstructed using symmetric and asymmetric KWIC windows of 3 different temporal durations. Simulated results were compared against temporal modulation transfer function predictions, experimental results, and the original simulated temperatures. RESULTS The temporal modulation transfer function shows that temporal resolution with KWIC reconstructions depend on the object size. The KWIC window duration affected SNR and severity of undersampling artifacts. Accuracy and response delay improved as the KWIC window duration decreased or the size of the heated region within the KWIC plane increased. Precision worsened as the window duration decreased. Using a symmetric window eliminated the response delay to heated region size but introduced a large reconstruction delay. CONCLUSION The accuracy and precision of proton resonance frequency temperature measurements from a stack-of-stars acquisition using a sliding KWIC window reconstruction are dependent on the size of the KWIC window and the size and shape of the heated region. The temporal modulation transfer function of KWIC reconstructions for any object size can predict the temporal response to changes in signal being acquired, such as temperature and contrast enhancement.
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Affiliation(s)
- Bryant T Svedin
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah
| | - Christopher R Dillon
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah
| | - Dennis L Parker
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah
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12
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Peek MCL, Ahmed M, Scudder J, Baker R, Charalampoudis P, Pinder SE, Douek M. High-intensity focused ultrasound in the treatment of breast fibroadenomata (HIFU-F trial). Int J Hyperthermia 2017; 34:1002-1009. [PMID: 28854826 DOI: 10.1080/02656736.2017.1373865] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
BACKGROUND High-intensity focussed ultrasound (HIFU) is a non-invasive ablative technique utilising the application of high frequency ultrasound (US) pressure waves to cause tissue necrosis. This emerging technology is currently limited by prolonged treatment times. The aim of the HIFU-F trial was to perform circumferential HIFU treatment as a means of shortening treatment times. METHODS A prospective trial was set up to treat 50 consecutive patients ≥18 years of age. Eligible patients possessed symptomatic fibroadenomata, visible on US. Patients ≥25 years of age required histological confirmation of the diagnosis. Primary outcome measures were reduction in treatment time, reduction in volume on US after 12 months and complication rates. RESULTS HIFU treatment was performed in 51 patients (53 treatments) with a mean age of 29.8 years (SD 7.2 years) and a diameter of 2.6 cm (SD 1.4 cm). Circumferential ablation reduced treatment times by an estimated 19.9 min (SD 25.1 min), which is a 29.4% (SD 15.2%) reduction compared with whole lesion ablation. Volume reduction of 43.2% (SD 35.4%; p < 0.005, paired t-test) was observed on US at 12 months post-treatment. Local complications completely resolved at 1 month apart from skin hyper-pigmentation, which persisted in nine cases at three months, six cases at 6 months and six at 12 months. CONCLUSION Circumferential HIFU treatment for breast fibroadenomata is feasible to reduce both lesion size and treatment time. HIFU is a non-invasive alternative technique for the treatment of breast fibroadenomata. ISRCTN registration: 76622747.
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Affiliation(s)
- M C L Peek
- a Division of Cancer Studies , King's College London, Guy's Hospital Campus , London , Great Britain.,b Guy's and St. Thomas' NHS Foundation Trust , London , Great Britain
| | - M Ahmed
- a Division of Cancer Studies , King's College London, Guy's Hospital Campus , London , Great Britain.,b Guy's and St. Thomas' NHS Foundation Trust , London , Great Britain
| | - J Scudder
- b Guy's and St. Thomas' NHS Foundation Trust , London , Great Britain
| | - R Baker
- c School of Business , University of Salford , Salford , Great Britain
| | - P Charalampoudis
- b Guy's and St. Thomas' NHS Foundation Trust , London , Great Britain
| | - S E Pinder
- a Division of Cancer Studies , King's College London, Guy's Hospital Campus , London , Great Britain.,b Guy's and St. Thomas' NHS Foundation Trust , London , Great Britain
| | - M Douek
- a Division of Cancer Studies , King's College London, Guy's Hospital Campus , London , Great Britain.,b Guy's and St. Thomas' NHS Foundation Trust , London , Great Britain
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Svedin BT, Payne A, Bolster BD, Parker DL. Multiecho pseudo-golden angle stack of stars thermometry with high spatial and temporal resolution using k-space weighted image contrast. Magn Reson Med 2017. [PMID: 28643383 DOI: 10.1002/mrm.26797] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE Implement and evaluate a 3D MRI method to measure temperature changes with high spatial and temporal resolution and large field of view. METHODS A multiecho pseudo-golden angle stack-of-stars (SOS) sequence with k-space weighted image contrast (KWIC) reconstruction was implemented to simultaneously measure multiple quantities, including temperature, initial signal magnitude M(0), transverse relaxation time ( T2*), and water/fat images. Respiration artifacts were corrected using self-navigation. KWIC artifacts were removed using a multi-baseline library. The phases of the multiple echo images were combined to improve proton resonance frequency precision. Temperature precision was tested through in vivo breast imaging (N = 5 healthy volunteers) using both coronal and sagittal orientations and with focused ultrasound (FUS) heating in a pork phantom using a breast specific MR-guided FUS system. RESULTS Temperature measurement precision was significantly improved after echo combination when compared with the no echo combination case (spatial average of the standard deviation through time of 0.3-1.0 and 0.7-1.9°C, respectively). Temperature measurement accuracy during heating was comparable to a 3D seg-EPI sequence. M(0) and T2* values showed temperature dependence during heating in pork adipose tissue. CONCLUSION A self-navigated 3D multiecho SOS sequence with dynamic KWIC reconstruction is a promising thermometry method that provides multiple temperature sensitive quantitative values. Magn Reson Med 79:1407-1419, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Bryant T Svedin
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | - Allison Payne
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | | | - Dennis L Parker
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
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Ellens NPK, Partanen A. Preclinical MRI-Guided Focused Ultrasound: A Review of Systems and Current Practices. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2017; 64:291-305. [PMID: 27662675 DOI: 10.1109/tuffc.2016.2609238] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Effective preclinical research is a vital component in the development of MRI-guided focused ultrasound (MRgFUS) and its translation to clinic. In this review, we seek to outline the challenges at hand for effective preclinical research, survey different solutions, and underline best practices. Furthermore, we summarize efforts to build and characterize dedicated preclinical MRgFUS equipment, including lab prototypes and available commercial products. Finally, we discuss constraints and considerations specific to using clinical MRgFUS equipment in preclinical research. Specifically, we examine additional hardware that has been used to adapt clinical MRgFUS equipment to better position, constrain, and image preclinical subjects, as well as software solutions that have been used to extend the potential and capabilities of clinical devices.
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Peek MCL, Ahmed M, Scudder J, Baker R, Pinder SE, Douek M. High intensity focused ultrasound in the treatment of breast fibroadenomata: results of the HIFU-F trial. Int J Hyperthermia 2016; 32:881-888. [DOI: 10.1080/02656736.2016.1212278] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- M. C. L. Peek
- Division of Cancer Studies, King’s College London, London, UK
- Guy’s and St Thomas’ NHS Foundation Trust, London, UK
| | - M. Ahmed
- Division of Cancer Studies, King’s College London, London, UK
| | - J. Scudder
- Guy’s and St Thomas’ NHS Foundation Trust, London, UK
| | - R. Baker
- School of Business, University of Salford, Salford, UK
| | - S. E. Pinder
- Division of Cancer Studies, King’s College London, London, UK
- Guy’s and St Thomas’ NHS Foundation Trust, London, UK
| | - M. Douek
- Division of Cancer Studies, King’s College London, London, UK
- Guy’s and St Thomas’ NHS Foundation Trust, London, UK
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16
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Svedin BT, Beck MJ, Hadley JR, Merrill R, de Bever JT, Bolster BD, Payne A, Parker DL. Focal point determination in magnetic resonance-guided focused ultrasound using tracking coils. Magn Reson Med 2016; 77:2424-2430. [PMID: 27418429 DOI: 10.1002/mrm.26294] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 05/07/2016] [Accepted: 05/11/2016] [Indexed: 11/08/2022]
Abstract
PURPOSE To develop a method for rapid prediction of the geometric focus location in MR coordinates of a focused ultrasound (US) transducer with arbitrary position and orientation without sonicating. METHODS Three small tracker coil circuits were designed, constructed, attached to the transducer housing of a breast-specific MR-guided focused US (MRgFUS) system with 5 degrees of freedom, and connected to receiver channel inputs of an MRI scanner. A one-dimensional sequence applied in three orthogonal directions determined the position of each tracker, which was then corrected for gradient nonlinearity. In a calibration step, low-level heating located the US focus in one transducer position orientation where the tracker positions were also known. Subsequent US focus locations were determined from the isometric transformation of the trackers. The accuracy of this method was verified by comparing the tracking coil predictions to thermal center of mass calculated using MR thermometry data acquired at 16 different transducer positions for MRgFUS sonications in a homogeneous gelatin phantom. RESULTS The tracker coil predicted focus was an average distance of 2.1 ± 1.1 mm from the thermal center of mass. The one-dimensional locator sequence and prediction calculations took less than 1 s to perform. CONCLUSION This technique accurately predicts the geometric focus for a transducer with arbitrary position and orientation without sonicating. Magn Reson Med 77:2424-2430, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Bryant T Svedin
- Radiology Department, Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | - Michael J Beck
- Radiology Department, Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | - J Rock Hadley
- Radiology Department, Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | - Robb Merrill
- Radiology Department, Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | - Joshua T de Bever
- Radiology Department, Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | - Bradley D Bolster
- Radiology Department, Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | - Allison Payne
- Radiology Department, Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | - Dennis L Parker
- Radiology Department, Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
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Farrer AI, Almquist S, Dillon CR, Neumayer LA, Parker DL, Christensen DA, Payne A. Phase aberration simulation study of MRgFUS breast treatments. Med Phys 2016; 43:1374-84. [PMID: 26936722 PMCID: PMC4769272 DOI: 10.1118/1.4941013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 01/11/2016] [Accepted: 01/18/2016] [Indexed: 01/24/2023] Open
Abstract
PURPOSE This simulation study evaluates the effects of phase aberration in breast MR-guided focused ultrasound (MRgFUS) ablation treatments performed with a phased-array transducer positioned laterally to the breast. A quantification of these effects in terms of thermal dose delivery and the potential benefits of phase correction is demonstrated in four heterogeneous breast numerical models. METHODS To evaluate the effects of varying breast tissue properties on the quality of the focus, four female volunteers with confirmed benign fibroadenomas were imaged using 3T MRI. These images were segmented into numerical models with six tissue types, with each tissue type assigned standard acoustic properties from the literature. Simulations for a single-plane 16-point raster-scan treatment trajectory centered in a fibroadenoma in each modeled breast were performed for a breast-specific MRgFUS system. At each of the 16 points, pressure patterns both with and without applying a phase correction technique were determined with the hybrid-angular spectrum method. Corrected phase patterns were obtained using a simulation-based phase aberration correction technique to adjust each element's transmit phase to obtain maximized constructive interference at the desired focus. Thermal simulations were performed for both the corrected and uncorrected pressure patterns using a finite-difference implementation of the Pennes bioheat equation. The effect of phase correction was evaluated through comparison of thermal dose accumulation both within and outside a defined treatment volume. Treatment results using corrected and uncorrected phase aberration simulations were compared by evaluating the power required to achieve a 20 °C temperature rise at the first treatment location. The extent of the volumes that received a minimum thermal dose of 240 CEM at 43 °C inside the intended treatment volume as well as the volume in the remaining breast tissues was also evaluated in the form of a dose volume ratio (DVR), a DVR percent change between corrected and uncorrected phases, and an additional metric that measured phase spread. RESULTS With phase aberration correction applied, there was an improvement in the focus for all breast anatomies as quantified by a reduction in power required (13%-102%) to reach 20 °C when compared to uncorrected simulations. Also, the DVR percent change increased by 5%-77% in seven out of eight cases, indicating an improvement to the treatment as measured by a reduction in thermal dose deposited to the nontreatment tissues. Breast compositions with a higher degree of heterogeneity along the ultrasound beam path showed greater reductions in thermal dose delivered outside of the treatment volume with correction applied than beam trajectories that propagated through more homogeneous breast compositions. An increasing linear trend was observed between the DVR percent change and the phase-spread metric (R(2) = 0.68). CONCLUSIONS These results indicate that performing phase aberration correction for breast MRgFUS treatments is beneficial for the small-aperture transducer (14.4 × 9.8 cm) evaluated in this work. While all breast anatomies could benefit from phase aberration correction, greater benefits are observed in more heterogeneous anatomies.
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Affiliation(s)
- Alexis I Farrer
- Department of Bioengineering, University of Utah, 36 South Wasatch Drive, Room 3100, Salt Lake City, Utah 84112
| | - Scott Almquist
- Department of Bioengineering, University of Utah, 36 South Wasatch Drive, Room 3100, Salt Lake City, Utah 84112
| | - Christopher R Dillon
- Department of Bioengineering, University of Utah, 36 South Wasatch Drive, Room 3100, Salt Lake City, Utah 84112
| | - Leigh A Neumayer
- Department of Bioengineering, University of Utah, 36 South Wasatch Drive, Room 3100, Salt Lake City, Utah 84112
| | - Dennis L Parker
- Department of Bioengineering, University of Utah, 36 South Wasatch Drive, Room 3100, Salt Lake City, Utah 84112
| | - Douglas A Christensen
- Department of Bioengineering, University of Utah, 36 South Wasatch Drive, Room 3100, Salt Lake City, Utah 84112
| | - Allison Payne
- Department of Bioengineering, University of Utah, 36 South Wasatch Drive, Room 3100, Salt Lake City, Utah 84112
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Knuttel FM, van den Bosch MAAJ. Magnetic Resonance-Guided High Intensity Focused Ultrasound Ablation of Breast Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 880:65-81. [PMID: 26486332 DOI: 10.1007/978-3-319-22536-4_4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This chapter describes several aspects of MR-HIFU treatment for breast cancer. The current and future applications, technical developments and clinical results are discussed. MR-HIFU ablation is under investigation for the treatment of breast cancer, but is not yet ready for clinical implementation. Firstly, the efficacy of MR-HIFU ablation should be investigated in large trials. The existing literature shows that results of initial, small studies are moderate, but opportunities for improvement are available. Careful patient selection, taking treatment margins into account and using a dedicated breast system might improve treatment outcomes. MRI-guidance has proven to be beneficial for the accuracy and safety of HIFU treatments because of its usefulness before, during and after treatments. In conclusion, MR-HIFU is promising for the treatment of breast cancer and might lead to a change in breast cancer care in the future.
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Affiliation(s)
- Floortje M Knuttel
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
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Peek MCL, Ahmed M, Napoli A, ten Haken B, McWilliams S, Usiskin SI, Pinder SE, van Hemelrijck M, Douek M. Systematic review of high-intensity focused ultrasound ablation in the treatment of breast cancer. Br J Surg 2015; 102:873-82; discussion 882. [PMID: 26095255 DOI: 10.1002/bjs.9793] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 10/14/2014] [Accepted: 01/27/2015] [Indexed: 01/14/2023]
Abstract
BACKGROUND A systematic review was undertaken to assess the clinical efficacy of non-invasive high-intensity focused ultrasound (HIFU) ablation in the treatment of breast cancer. METHODS MEDLINE/PubMed library databases were used to identify all studies published up to December 2013 that evaluated the role of HIFU ablation in the treatment of breast cancer. Studies were eligible if they were performed on patients with breast cancer and objectively recorded at least one clinical outcome measure of response (imaging, histopathological or cosmetic) to HIFU treatment. RESULTS Nine studies fulfilled the inclusion criteria. The absence of tumour or residual tumour after treatment was reported for 95·8 per cent of patients (160 of 167). No residual tumour was found in 46·2 per cent (55 of 119; range 17-100 per cent), less than 10 per cent residual tumour in 29·4 per cent (35 of 119; range 0-53 per cent), and between 10 and 90 per cent residual tumour in 22·7 per cent (27 of 119; range 0-60 per cent). The most common complication associated with HIFU ablation was pain (40·1 per cent) and less frequently oedema (16·8 per cent), skin burn (4·2 per cent) and pectoralis major injury (3·6 per cent). MRI showed an absence of contrast enhancement after treatment in 82 per cent of patients (31 of 38; range 50-100 per cent), indicative of coagulative necrosis. Correlation of contrast enhancement on pretreatment and post-treatment MRI successfully predicted the presence of residual disease. CONCLUSION HIFU treatment can induce coagulative necrosis in breast cancers. Complete ablation has not been reported consistently on histopathology and no imaging modality has been able confidently to predict the percentage of complete ablation. Consistent tumour and margin necrosis with reliable follow-up imaging are required before HIFU ablation can be evaluated within large, prospective clinical trials.
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Affiliation(s)
- M C L Peek
- Research Oncology, King's College London, London, UK.,Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - M Ahmed
- Research Oncology, King's College London, London, UK
| | - A Napoli
- Department of Radiological Sciences, Sapienza University of Rome, School of Medicine, Rome, Italy
| | - B ten Haken
- Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - S McWilliams
- Research Oncology, King's College London, London, UK
| | - S I Usiskin
- Department of Radiology, St Bartholomew's Hospital, London, UK
| | - S E Pinder
- Research Oncology, King's College London, London, UK
| | - M van Hemelrijck
- Cancer Epidemiology Group, Division of Cancer Studies, King's College London, London, UK
| | - M Douek
- Research Oncology, King's College London, London, UK
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Svedin BT, Payne A, Parker DL. Respiration artifact correction in three-dimensional proton resonance frequency MR thermometry using phase navigators. Magn Reson Med 2015; 76:206-13. [PMID: 26272108 DOI: 10.1002/mrm.25860] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 06/19/2015] [Accepted: 07/11/2015] [Indexed: 11/07/2022]
Abstract
PURPOSE To develop reliable three-dimensional (3D) segmented echo planar imaging (seg-EPI) proton resonance frequency (PRF) temperature monitoring in the presence of respiration-induced B0 variation. METHODS A free induction decay (FID) phase navigator was inserted into a 3D seg-EPI sequence before and after EPI readout to monitor B0 field variations. Using the field change estimates, the phase of each k-space line was adjusted to remove the additional phase from the respiratory induced off-resonance. This correction technique was evaluated while heating with MR-guided focused ultrasound (MRgFUS) in phantoms with simulated breathing and during nonheating conditions in healthy in vivo breasts. RESULTS With k-space phase correction, the standard deviation of magnitude images and PRF temperature measurements in breast from five volunteers improved by an average factor of 1.5 and 2.1, respectively. Improved accuracy of temperature estimates was observed after correction while heating with MRgFUS in phantoms. CONCLUSION Phase correction based on two FID navigators placed before and after the echo train provides promising results for implementing 3D monitoring of thermal therapy treatments in the presence of field variations due to respiration. Magn Reson Med 76:206-213, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Bryant T Svedin
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | - Allison Payne
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | - Dennis L Parker
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
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Deckers R, Merckel LG, Denis de Senneville B, Schubert G, Köhler M, Knuttel FM, Mali WPTM, Moonen CTW, van den Bosch MAAJ, Bartels LW. Performance analysis of a dedicated breast MR-HIFU system for tumor ablation in breast cancer patients. Phys Med Biol 2015; 60:5527-42. [DOI: 10.1088/0031-9155/60/14/5527] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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