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https://www.readbyqxmd.com/read/28812002/image-guided-thermal-ablation-with-mr-based-thermometry
#1
REVIEW
Mingming Zhu, Ziqi Sun, Chin K Ng
Thermal ablation techniques such as radiofrequency, microwave, high intensity focused ultrasound (HIFU) and laser have been used as minimally invasive strategies for the treatment of variety of cancers. MR thermometry methods are readily available for monitoring thermal distribution and deposition in real time, leading to decrease of incidents of normal tissue damage around targeted lesion. HIFU and laser-induced thermal therapy (LITT) are the two widely accepted tumor ablation techniques because of their compatibility with MR systems...
June 2017: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28795419/simultaneous-mr-thermometry-and-acoustic-radiation-force-imaging-using-interleaved-acquisition
#2
Joshua T de Bever, Henrik Odéen, Lorne W Hofstetter, Dennis L Parker
PURPOSE: A novel and practical method for simultaneously performing MR acoustic radiation force imaging (ARFI) and proton resonance frequency (PRF)-shift thermometry has been developed and tested. This could be an important tool for evaluating the success of MR-guided focused ultrasound procedures for which MR-thermometry measures temperature and thermal dose and MR-ARFI detects changes in tissue mechanical properties. METHODS: MR imaging was performed using a gradient recalled echo segmented echo-planar imaging pulse sequence with bipolar motion encoding gradients (MEG)...
August 10, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28748092/a-focused-ultrasound-treatment-system-for-moving-targets-part-i-generic-system-design-and-in-silico-first-stage-evaluation
#3
Michael Schwenke, Jan Strehlow, Daniel Demedts, Sabrina Haase, Diego Barrios Romero, Sven Rothlübbers, Caroline von Dresky, Stephan Zidowitz, Joachim Georgii, Senay Mihcin, Mario Bezzi, Christine Tanner, Giora Sat, Yoav Levy, Jürgen Jenne, Matthias Günther, Andreas Melzer, Tobias Preusser
BACKGROUND: Focused ultrasound (FUS) is entering clinical routine as a treatment option. Currently, no clinically available FUS treatment system features automated respiratory motion compensation. The required quality standards make developing such a system challenging. METHODS: A novel FUS treatment system with motion compensation is described, developed with the goal of clinical use. The system comprises a clinically available MR device and FUS transducer system...
2017: Journal of Therapeutic Ultrasound
https://www.readbyqxmd.com/read/28728442/an-integrated-platform-for-small-animal-hyperthermia-investigations-under-ultra-high-field-mri-guidance
#4
Sergio Curto, Pegah Faridi, Tej B Shrestha, Marla Pyle, Leila Maurmann, Deryl Troyer, Stefan H Bossmann, Punit Prakash
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...
July 21, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28714565/mri-compatible-breast-rib-phantom-for-evaluating-ultrasonic-thermal-exposures
#5
Georgios Menikou, Marinos Yiannakou, Christos Yiallouras, Cleanthis Ioannides, Christakis Damianou
INTRODUCTION: The target of this study was the development of a magnetic resonance imaging (MRI) compatible breast phantom for focused ultrasound which includes plastic (ABS) ribs. The objective of the current study was the evaluation of a focused ultrasound procedure using the proposed phantom that eliminates rib heating. MATERIAL AND METHODS: The proposed phantom was evaluated using two different focused ultrasound exposures. The surrounding breast tissue was mimicked using an agar-silica-evaporation milk gel (2% w/v - 2% w/v - 40% v/v)...
July 17, 2017: International Journal of Medical Robotics + Computer Assisted Surgery: MRCAS
https://www.readbyqxmd.com/read/28656726/correlation-distance-dependence-of-the-resonance-frequency-of-intermolecular-zero-quantum-coherences-and-its-implication-for-mr-thermometry
#6
Le Zhang, Andrew McCallister, Karl M Koshlap, Rosa Tamara Branca
PURPOSE: Because the resonance frequency of water-fat intermolecular zero-quantum coherences (iZQCs) reflects the water-fat frequency separation at the microscopic scale, these frequencies have been proposed and used as a mean to obtain more accurate temperature information. The purpose of this work was to investigate the dependence of the water-fat iZQC resonance frequency on sample microstructure and on the specific choice of the correlation distance. METHODS: The effect of water-fat susceptibility gradients on the water-methylene iZQC resonance frequency was first computed and then measured for different water-fat emulsions and for a mixture of porcine muscle and fat...
June 27, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28654336/focal-therapy-for-prostate-cancer-with-in-bore-mr-guided-focused-ultrasound-two-year-follow-up-of-a-phase-i-trial-complications-and-functional-outcomes
#7
Kae Jack Tay, Christopher W S Cheng, Weber K O Lau, James Khoo, Choon Hua Thng, Jin Wei Kwek
Purpose To report the safety profile and 2-year functional outcomes of in-bore magnetic resonance (MR)-guided focused ultrasound on single cancer foci in men with prostate cancer. Materials and Methods Ethics approval was obtained from the centralized institutional review board for this prospective single-arm study, and patients provided informed consent. Patients with untreated low-volume low-grade prostate cancer (clinical stage T2a or lower; Gleason score, 3+3; index tumor ≤10 mm(3)) underwent MR-guided focused ultrasound between July 2011 and February 2013...
June 26, 2017: Radiology
https://www.readbyqxmd.com/read/28646608/fluid-filling-of-the-digestive-tract-for-improved-proton-resonance-frequency-shift-based-mr-thermometry-in-the-pancreas
#8
Cyril J Ferrer, Lambertus W Bartels, Marijn van Stralen, Baudouin Denis de Senneville, Chrit T W Moonen, Clemens Bos
PURPOSE: To demonstrate that fluid filling of the digestive tract improves the performance of respiratory motion-compensated proton resonance frequency shift (PRFS)-based magnetic resonance (MR) thermometry in the pancreas. MATERIALS AND METHODS: In seven volunteers (without heating), we evaluated PRFS thermometry in the pancreas with and without filling of the surrounding digestive tract. All data acquisition was performed at 1.5T, then all datasets were analyzed and compared with three different PRFS respiratory motion-compensated thermometry methods: gating, multibaseline, and referenceless...
June 24, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28643383/multiecho-pseudo-golden-angle-stack-of-stars-thermometry-with-high-spatial-and-temporal-resolution-using-k-space-weighted-image-contrast
#9
Bryant T Svedin, Allison Payne, Bradley D Bolster, Dennis L Parker
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...
June 22, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28643045/validation-of-a-mathematical-model-for-laser-induced-thermotherapy-in-liver-tissue
#10
F Hübner, C Leithäuser, B Bazrafshan, N Siedow, T J Vogl
The purpose of the study was to develop a simulation approach for laser-induced thermotherapy (LITT) that is based on mathematical models for radiation transport, heat transport, and tissue damage. The LITT ablation was applied to ex vivo pig liver tissue. Experiments were repeated with different laser powers, i.e., 22-34 W, and flow rates of the cooling water in the applicator system, i.e., 47-92 ml/min. During the procedure, the temperature was measured in the liver sample at different distances to the applicator as well as in the cooling circuit using a fiber optic thermometer...
August 2017: Lasers in Medical Science
https://www.readbyqxmd.com/read/28598900/interleaved-mapping-of-temperature-and-longitudinal-relaxation-rate-to-monitor-drug-delivery-during-magnetic-resonance-guided-high-intensity-focused-ultrasound-induced-hyperthermia
#11
Esther Kneepkens, Edwin Heijman, Jochen Keupp, Steffen Weiss, Klaas Nicolay, Holger Grüll
OBJECTIVES: Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a method to heat lesions noninvasively to a stable, elevated temperature and a well-suited method to induce local hyperthermia (41°C-43°C) in deep-seated tissues. Magnetic Resonance (MR) imaging provides therapy planning on anatomical images and offers temperature feedback based on near-real-time MR thermometry. Although constant acquisition of MR thermometry data is crucial to ensure prolonged hyperthermia, it limits the freedom to perform measurements of other MR parameters, which are of interest during hyperthermia treatments...
June 8, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28595499/thermal-diffusivity-and-perfusion-constants-from-in-vivo-mr-guided-focused-ultrasound-treatments-a-feasibility-study
#12
Christopher R Dillon, Viola Rieke, Pejman Ghanouni, Allison Payne
PURPOSE: This study investigates the feasibility of non-invasively determining thermal diffusivity (α) and the Pennes perfusion parameter (w) from preclinical and clinical magnetic resonance-guided focused ultrasound (MRgFUS) temperature data. MATERIALS AND METHODS: Pre-clinical MRgFUS experiments were performed in rabbit muscle (N = 3, 28 sonications) using three-dimensional MR thermometry. 8 sonications were made in a clinical QA phantom with two-dimensional thermometry...
June 8, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28590938/combined-passive-acoustic-mapping-and-magnetic-resonance-thermometry-for-monitoring-phase-shift-nanoemulsion-enhanced-focused-ultrasound-therapy
#13
Calum Crake, F Can Meral, Mark Burgess, Iason Papademetriou, Nathan McDannold, Tyrone Porter
Focused ultrasound (FUS) has the potential to enable precise, image-guided noninvasive surgery for the treatment of cancer in which tumors are identified and destroyed in a single integrated procedure. However, success of the method in highly vascular organs has been limited due to heat losses to perfusion, requiring development of techniques to locally enhance energy absorption and heating. In addition, FUS procedures are conventionally monitored using MRI, which provides excellent anatomical images and can map temperature, but is not capable of capturing the full gamut of available data such as the acoustic emissions generated during this inherently acoustically-driven procedure...
June 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28580706/mr-techniques-for-guiding-high-intensity-focused-ultrasound-hifu-treatments
#14
REVIEW
Kagayaki Kuroda
To make full use of the ability of magnetic resonance (MR) to guide high-intensity focused ultrasound (HIFU) treatment, effort has been made to improve techniques for thermometry, motion tracking, and sound beam visualization. For monitoring rapid temperature elevation with proton resonance frequency (PRF) shift, data acquisition and processing can be accelerated with parallel imaging and/or sparse sampling in conjunction with appropriate signal processing methods. Thermometry should be robust against tissue motion, motion-induced magnetic field variation, and susceptibility change...
June 5, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28572977/acoustic-and-thermal-characterization-of-agar-based-phantoms-used-for-evaluating-focused-ultrasound-exposures
#15
Georgios Menikou, Christakis Damianou
BACKGROUND: This study describes a series of experimental work completed towards characterizing candidate materials for fabricating brain and muscle tissue mimicking phantoms. METHODS: The acoustic speed, attenuation, impedance, thermal diffusivity, specific heat and thermal conductivity were measured. RESULTS: The resulting brain (2% w/v agar-1.2% w/v Silica Dioxide-25%v/v evaporated milk) and muscle tissue recipe (2% w/v agar-2% w/v Silica Dioxide-40%v/v evaporated milk) introduced a total attenuation coefficient of 0...
2017: Journal of Therapeutic Ultrasound
https://www.readbyqxmd.com/read/28560040/spatially-segmented-undersampled-mri-temperature-reconstruction-for-transcranial-mr-guided-focused-ultrasound
#16
Pooja Gaur, Beat Werner, Xue Feng, Samuel W Fielden, Craig H Meyer, William A Grissom
BACKGROUND: Volumetric thermometry with fine spatiotemporal resolution is desirable to monitor MR-guided focused ultrasound (MRgFUS) procedures in the brain, but requires some form of accelerated imaging. Accelerated MR temperature imaging methods have been developed that undersample k-space and leverage signal correlations over time to suppress the resulting undersampling artifacts. However, in transcranial MRgFUS treatments, the water bath surrounding the skull creates signal variations that do not follow those correlations, leading to temperature errors in the brain due to signal aliasing...
2017: Journal of Therapeutic Ultrasound
https://www.readbyqxmd.com/read/28557798/thermal-ablation-of-a-confluent-lesion-in-the-porcine-kidney-with-a-clinically-available-mr-hifu-system
#17
J M M van Breugel, M de Greef, J W Wijlemans, G Schubert, M A A J van den Bosch, C T W Moonen, M G Ries
The incidence of small renal masses (SRMs) sized  <4 cm has increased over the decades (as co-findings/or due to introduction of cross sectional imaging). Currently, partial nephrectomy (PN) or watchful waiting is advised in these patients. Ultimately, 80-90% of these SRMs require surgical treatment and PN is associated with a 15% complication rate. In this aging population, with possible comorbidities and poor health condition, both PN and watchful waiting are non-ideal treatment options. This resulted in an increased need for early, non-invasive treatment strategies such as MR-guided high intensity focused ultrasound (MR-HIFU)...
July 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28541897/capacitive-micromachined-ultrasound-transducers-for-interstitial-high-intensity-ultrasound-therapies
#18
W Apoutou N'Djin, Bjoern Gerold, Jeremy Vion-Bailly, Michael S Canney, An Nguyen-Dinh, Alexandre Carpentier, Jean-Yves Chapelon
Capacitive micromachined ultrasound transducers (CMUTs) exhibit several potential advantages over conventional piezo technologies for use in therapeutic ultrasound (US) devices, including ease of miniaturization and integration with electronics, broad bandwidth (>several megahertz), and compatibility with magnetic resonance imaging (MRI). In this paper, the electroacoustic performance of CMUTs designed for interstitial high-intensity contact US (HICU) applications was evaluated and the feasibility of generating US-induced heating and thermal destruction of biological tissues was studied...
August 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28540820/theoretical-model-for-laser-ablation-outcome-predictions-in-brain-calibration-and-validation-on-clinical-mr-thermometry-images
#19
Samuel John Fahrenholtz, Reza Madankan, Shabbar Danish, John D Hazle, R Jason Stafford, David Fuentes
PURPOSE: Neurosurgical laser ablation is experiencing a renaissance. Computational tools for ablation planning aim to further improve the intervention. Here, global optimisation and inverse problems are demonstrated to train a model that predicts maximum laser ablation extent. METHODS: A closed-form steady state model is trained on and then subsequently compared to N = 20 retrospective clinical MR thermometry datasets. Dice similarity coefficient (DSC) is calculated to provide a measure of region overlap between the 57 °C isotherms of the thermometry data and the model-predicted ablation regions; 57 °C is a tissue death surrogate at thermal steady state...
May 19, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28516051/evaluation-of-mr-thermometry-with-proton-resonance-frequency-method-at-7t
#20
Ping Wang
Quantitative and non-invasive temperature mapping using magnetic resonance imaging (MRI) provides a unique way to measure temperature evolution inside biological tissues. The method is widely used in thermal ablation procedures with magnetic fields at or below 3T. In this paper, the sensitivity of the MRI thermometry at 7T was studied using a proton resonance frequency (PRF)-based technique. We first used an agarose gel phantom with MR-compatible thermometry to calibrate the temperature coefficient, and then this temperature coefficient was employed to measure the internal temperature in both ex vivo (beef muscle) and in vivo (rat) experiments using focused ultrasound heating...
April 2017: Quantitative Imaging in Medicine and Surgery
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