1
|
Payne A, Minalga E, Merrill R, Parker DL, Hadley JR. Technical Note: Effect of transducer position and ground plane configuration on image quality in MR-guided focused ultrasound therapies. Med Phys 2020; 47:2350-2355. [PMID: 32170866 PMCID: PMC7802121 DOI: 10.1002/mp.14138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 12/21/2022] Open
Abstract
PURPOSE To evaluate the effect of a focused ultrasound transducer position and ground plane configuration on magnetic resonance image quality. METHODS The effect of transducer position with respect to the MRI B0 field and the radiofrequency receive coils was evaluated in a breast-specific MRgFUS system with an integrated RF phased-array coil. Image signal-to-noise ratio was evaluated at different transducer locations. The effect of ultrasound transducer ground plane configuration was evaluated using a replica transducer with 12 ground plane configurations. All evaluations were performed at 3 Tesla. RESULTS Both transducer position and ground plane configuration were found to have a considerable effect on overall image SNR. A 67% increase in SNR was achieved by positioning the transducer face perpendicular to the B0 field. A 25% increase in SNR was achieved by segmenting the replica transducer ground plane from one continuous plane to nine individual segments. CONCLUSIONS Advances in focused ultrasound hardware allow for integrated radiofrequency MRI coils as well as adjustable transducer positioning. The placement of the ultrasound transducer with respect to both the magnetic field and RF coils can have a considerable effect on image SNR and the resulting MR images that are used for MR-guided focused ultrasound treatment planning, monitoring and assessment.
Collapse
Affiliation(s)
- Allison Payne
- Utah Center for Advanced Imaging Research, Dept. of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA 84108
| | - Emilee Minalga
- Utah Center for Advanced Imaging Research, Dept. of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA 84108
| | - Robb Merrill
- Utah Center for Advanced Imaging Research, Dept. of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA 84108
| | - Dennis L. Parker
- Utah Center for Advanced Imaging Research, Dept. of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA 84108
| | - J. Rock Hadley
- Utah Center for Advanced Imaging Research, Dept. of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA 84108
| |
Collapse
|
2
|
Kardoulaki EM, Syms RRA, Young IR, Choonee K, Rea M, Gedroyc WMW. Optothermal profile of an ablation catheter with integrated microcoil for MR-thermometry during Nd:YAG laser interstitial thermal therapies of the liver—an in-vitro experimental and theoretical study. Med Phys 2016; 42:1389-97. [PMID: 25735293 DOI: 10.1118/1.4908225] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Flexible microcoils integrated with ablation catheters can improve the temperature accuracy during local MR-thermometry in Nd:YAG laser interstitial thermal therapies. Here, the authors are concerned with obtaining a preliminary confirmation of the clinical utility of the modified catheter. They investigate whether the thin-film substrate and copper tracks of the printed coil inductor affect the symmetry of the thermal profile, and hence of the lesion produced. METHODS Transmission spectroscopy in the near infrared was performed to test for the attenuation at 1064 nm through the 25 μm thick Kapton substrate of the microcoil. The radial transmission profile of an infrared high-power, light emitting diode with >80% normalized power at 1064 nm was measured through a cross section of the modified applicator to assess the impact of the copper inductor on the optical profile. The measurements were performed in air, as well as with the applicator surrounded by two types of scattering media; crystals of NaCl and a layer of liver-mimicking gel phantom. A numerical model based on Huygens-Fresnel principle and finite element simulations, using a commercially available package (COMSOL Multiphysics), were employed to compare with the optical measurements. The impact of the modified optical profile on the thermal symmetry was assessed by examining the high resolution microcoil derived thermal maps from a Nd:YAG laser ablation performed on a liver-mimicking gel phantom. RESULTS Less than 30% attenuation through the Kapton film was verified. Shadowing behind the copper tracks was observed in air and the measured radial irradiation correlated well with the diffraction pattern calculated numerically using the Huygens-Fresnel principle. Both optical experiments and simulations, demonstrate that shadowing is mitigated by the scattering properties of a turbid medium. The microcoil derived thermal maps at the end of a Nd:YAG laser ablation performed on a gel phantom in a 3 T scanner confirm that the modified irradiation pattern does not disrupt the thermal symmetry, even though, unlike tissue, the gel is minimally scattering. CONCLUSIONS The results from this initial assessment indicate that microcoils can be safely integrated with ablation catheters and ensure that the complete necrosis of the liver tumor can still be achieved.
Collapse
Affiliation(s)
- Evdokia M Kardoulaki
- Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Richard R A Syms
- Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Ian R Young
- Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Kaushal Choonee
- Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Marc Rea
- Department of Radiology, Imperial College Healthcare NHS Trust, Paddington, London W2 1NY, United Kingdom
| | - Wladyslaw M W Gedroyc
- Department of Radiology, Imperial College Healthcare NHS Trust, Paddington, London W2 1NY, United Kingdom
| |
Collapse
|
3
|
Abstract
High intensity focused ultrasound (HIFU) is rapidly gaining clinical acceptance as a technique capable of providing non-invasive heating and ablation for a wide range of applications. Usually requiring only a single session, treatments are often conducted as day case procedures, with the patient either fully conscious, lightly sedated or under light general anesthesia. HIFU scores over other thermal ablation techniques because of the lack of necessity for the transcutaneous insertion of probes into the target tissue. Sources placed either outside the body (for treatment of tumors or abnormalities of the liver, kidney, breast, uterus, pancreas brain and bone), or in the rectum (for treatment of the prostate), provide rapid heating of a target tissue volume, the highly focused nature of the field leaving tissue in the ultrasound propagation path relatively unaffected. Numerous extra-corporeal, transrectal and interstitial devices have been designed to optimize application-specific treatment delivery for the wide-ranging areas of application that are now being explored with HIFU. Their principle of operation is described here, and an overview of their design principles is given.
Collapse
Affiliation(s)
- Gail Ter Haar
- Joint Department of Physics, The Institute of Cancer Research, Sutton, London, UK.
| |
Collapse
|
4
|
Ebbini ES, ter Haar G. Ultrasound-guided therapeutic focused ultrasound: current status and future directions. Int J Hyperthermia 2015; 31:77-89. [PMID: 25614047 DOI: 10.3109/02656736.2014.995238] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
This paper reviews ultrasound imaging methods for the guidance of therapeutic focused ultrasound (USgFUS), with emphasis on real-time preclinical methods. Guidance is interpreted in the broadest sense to include pretreatment planning, siting of the FUS focus, real-time monitoring of FUS-tissue interactions, and real-time control of exposure and damage assessment. The paper begins with an overview and brief historical background of the early methods used for monitoring FUS-tissue interactions. Current imaging methods are described, and discussed in terms of sensitivity and specificity of the localisation of the FUS effects in both therapeutic and sub-therapeutic modes. Thermal and non-thermal effects are considered. These include cavitation-enhanced heating, tissue water boiling and cavitation. Where appropriate, USgFUS methods are compared with similar methods implemented using other guidance modalities, e.g. magnetic resonance imaging. Conclusions are drawn regarding the clinical potential of the various guidance methods, and the feasibility and current status of real-time implementation.
Collapse
Affiliation(s)
- Emad S Ebbini
- Electrical and Computer Engineering, University of Minnesota Twin Cities , Minneapolis, Minnesota , USA and
| | | |
Collapse
|
5
|
Zucconi F, Colombo PE, Pasetto S, Lascialfari A, Ticca C, Torresin A. Analysis and reduction of thermal dose errors in MRgFUS treatment. Phys Med 2014; 30:111-6. [DOI: 10.1016/j.ejmp.2013.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Revised: 02/27/2013] [Accepted: 04/25/2013] [Indexed: 11/27/2022] Open
|
6
|
Rata M, Birlea V, Murillo A, Paquet C, Cotton F, Salomir R. Endoluminal MR-guided ultrasonic applicator embedding cylindrical phased-array transducers and opposed-solenoid detection coil. Magn Reson Med 2014; 73:417-26. [PMID: 24478117 DOI: 10.1002/mrm.25099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 11/18/2013] [Accepted: 12/07/2013] [Indexed: 12/20/2022]
Abstract
PURPOSE MR-guided high-intensity contact ultrasound (HICU) was suggested as an alternative therapy for esophageal and rectal cancer. To offer high-quality MR guidance, two prototypes of receive-only opposed-solenoid coil were integrated with 64-element cylindrical phased-array ultrasound transducers (rectal/esophageal). METHODS The design of integrated coils took into account the transducer geometry (360° acoustic window within endoluminal space). The rectal coil was sealed on a plastic support and placed reversibly on the transducer head. The esophageal coil was fully embedded within the transducer head, resulting in one indivisible device. Comparison of integrated versus external coils was performed on a clinical 1.5T scanner. RESULTS The integrated coils showed higher sensitivity compared with the standard extracorporeal coil with factors of up to 7.5 (rectal applicator) and 3.3 (esophageal applicator). High-resolution MR images for both anatomy (voxel 0.4 × 0.4 × 5 mm(3)) and thermometry (voxel 0.75 × 0.75 × 8 mm(3), 2 s/image) were acquired in vivo with the rectal endoscopic device. The temperature feedback loop accurately controlled multiple control points over the region of interest. CONCLUSION This study showed significant improvement of MR data quality using endoluminal integrated coils versus standard external coil. Inframillimeter spatial resolution and accurate feedback control of MR-guided HICU thermotherapy were achieved.
Collapse
Affiliation(s)
- Mihaela Rata
- INSERM, Therapeutic Applications of Ultrasound, U556 (currently LabTAU - U1032), Université de Lyon, Lyon, F-69003, France.,Université de Lyon, Université Claude Bernard Lyon 1, Lyon, F-69003, France
| | - Vlad Birlea
- INSERM, Therapeutic Applications of Ultrasound, U556 (currently LabTAU - U1032), Université de Lyon, Lyon, F-69003, France.,Babes-Bolyai University, Faculty of Physics, Cluj-Napoca, Romania
| | - Adriana Murillo
- INSERM, Therapeutic Applications of Ultrasound, U556 (currently LabTAU - U1032), Université de Lyon, Lyon, F-69003, France
| | - Christian Paquet
- Université de Lyon, VetAgro Sup, EA 4174, Marcy l'Etoile, F-69280, France
| | - François Cotton
- Université de Lyon, Université Claude Bernard Lyon 1, Lyon, F-69003, France.,MR Unit, Radiology Department, Lyon Sud University Hospital, Hospices Civils de Lyon, Pierre-Bénite, F-69495, France
| | - Rares Salomir
- INSERM, Therapeutic Applications of Ultrasound, U556 (currently LabTAU - U1032), Université de Lyon, Lyon, F-69003, France.,Radiology Department, Faculty of Medicine, University of Geneva, Geneva, CH-1211, Switzerland
| |
Collapse
|
7
|
Couppis A, Damianou C, Kyriacou P, Lafon C, Chavrier F, Chapelon JY, Birer A. Heart ablation using a planar rectangular high intensity ultrasound transducer and MRI guidance. ULTRASONICS 2012; 52:821-829. [PMID: 22525419 DOI: 10.1016/j.ultras.2012.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 01/31/2012] [Accepted: 03/26/2012] [Indexed: 05/31/2023]
Abstract
The aim of this study was to evaluate a flat rectangular (3×10mm(2)) MRI compatible transducer operating at 5MHz. The main task was to explore the feasibility of creating deep lesions in heart at a depth of at least 15mm. The size of thermal necrosis in heart tissue was estimated as a function of power and time using a simulation model. The system was then tested in an excised lamb heart. In this study, we were able to create lesions of 15mm deep with acoustic power of 6W for an exposure of approximately 1min. The contrast to noise ratio (CNR) between lesion and heart tissue was evaluated using fast spin echo (FSE). The CNR value was approximately 22 using T1W FSE. Maximum CNR was achieved with repetition time (TR) between 300 and 800ms. Using T2W FSE, the corresponding CNR was approximately 13 for the 14 in vivo experiments. The average lesion depth was 11.93mm with a standard deviation of 0.62mm. In vivo irradiation conditions were 6W for 60s. The size of the lesion in the other two dimensions was close to 3×10mm(2) (size of the transducer element).
Collapse
|
8
|
Kotopoulis S, Wang H, Cochran S, Postema M. Lithium niobate transducers for MRI-guided ultrasonic microsurgery. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2011; 58:1570-1576. [PMID: 21859576 DOI: 10.1109/tuffc.2011.1984] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Focused ultrasound surgery (FUS) is usually based on frequencies below 5 MHz-typically around 1 MHz. Although this allows good penetration into tissue, it limits the minimum lesion dimensions that can be achieved. In this study, we investigate devices to allow FUS at much higher frequencies, in principle, reducing the minimum lesion dimensions. Furthermore, FUS can produce deep-sub-millimeter demarcation between viable and necrosed tissue; high-frequency devices may allow this to be exploited in superficial applications which may include dermatology, ophthalmology, treatment of the vascular system, and treatment of early dysplasia in epithelial tissue. In this paper, we explain the methodology we have used to build high-frequency high-intensity transducers using Y-36°-cut lithium niobate. This material was chosen because its low losses give it the potential to allow very-high-frequency operation at harmonics of the fundamental operating frequency. A range of single-element transducers with center frequencies between 6.6 and 20.0 MHz were built and the transducers' efficiency and acoustic power output were measured. A focused 6.6-MHz transducer was built with multiple elements operating together and tested using an ultrasound phantom and MRI scans. It was shown to increase phantom temperature by 32°C in a localized area of 2.5 x 3.4 mm in the plane of the MRI scan. Ex vivo tests on poultry tissue were also performed and shown to create lesions of similar dimensions. This study, therefore, demonstrates that it is feasible to produce high-frequency transducers capable of high-resolution FUS using lithium niobate.
Collapse
Affiliation(s)
- Spiros Kotopoulis
- Department of Engineering, The University of Hull, Kingston upon Hull, UK
| | | | | | | |
Collapse
|
9
|
Rata M, Salomir R, Umathum R, Jenne J, Lafon C, Cotton F, Bock M. Endoluminal ultrasound applicator with an integrated RF coil for high-resolution magnetic resonance imaging-guided high-intensity contact ultrasound thermotherapy. Phys Med Biol 2008; 53:6549-67. [DOI: 10.1088/0031-9155/53/22/017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
10
|
Jolesz FA, McDannold N. Current status and future potential of MRI-guided focused ultrasound surgery. J Magn Reson Imaging 2008; 27:391-9. [PMID: 18219674 DOI: 10.1002/jmri.21261] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The combination of the imaging abilities of magnetic resonance imaging (MRI) with the ability to delivery energy to targets deep in the body noninvasively with focused ultrasound presents a disruptive technology with the potential to significantly affect healthcare. MRI offers precise targeting, visualization, and quantification of temperature changes and the ability to immediately evaluate the treatment. By exploiting different mechanisms, focused ultrasound offers a range of therapies, ranging from thermal ablation to targeted drug delivery. This article reviews recent preclinical and tests clinical of this technology.
Collapse
Affiliation(s)
- Ferenc A Jolesz
- Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
| | | |
Collapse
|
11
|
Li YS, Reid CN, McHale AP. Enhancing ultrasound-mediated cell membrane permeabilisation (sonoporation) using a high frequency pulse regime and implications for ultrasound-aided cancer chemotherapy. Cancer Lett 2008; 266:156-62. [PMID: 18367324 DOI: 10.1016/j.canlet.2008.02.041] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Revised: 02/18/2008] [Accepted: 02/19/2008] [Indexed: 10/22/2022]
Abstract
Delivering ultrasound to HeLa cells at 1MHz using a high frequency pulse regime (40kHz) and at a maximum energy density of 270Jcm(-2) resulted in significant cell membrane permeabilisation. Using FITC-dextran as a fluorogenic marker, optimally up to 64% of treated populations were permeabilised with cell viability remaining above 80%. Although cell membrane permeabilisation was observed in the presence of the microbubble-based ultrasound contrast agent, SonoVue, cell viability was severely compromised. Using the high frequency pulse regime in the absence of microbubbles, the LD50 of the cancer chemotherapeutic agent, camptothecin, was reduced from 58 to 18nM.
Collapse
Affiliation(s)
- Ying Suet Li
- School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, Co. Derry BT52 1SA, Northern Ireland, United Kingdom
| | | | | |
Collapse
|