Development of custom RF coils for use in a small animal platform for magnetic resonance-guided focused ultrasound hyperthermia compatible with a clinical MRI scanner

Abraham, Christopher Brian; Loree-Spacek, Jak; Drainville, Robert Andrew; Pichardo, Samuel; Curiel, Laura

doi:10.1080/02656736.2018.1503344

Cited by 4 publications

(1 citation statement)

References 40 publications

(61 reference statements)

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“…In addition, the relatively low signal-to-noise ratio (SNR) of the body coil and lack of acceleration capabilities are a large hindrance to a) the spatial resolution that can be achieved, b) the available sequences for imaging, and c) the temporal resolution of thermometry. Specialized imaging coils designed for MR guided focused ultrasound have been explored both in pre-clinical applications and in human applications outside of the head [11][12][13]. Although a split quadrature volume transmit/receive head coil and flexible printed receive coils have showed promising results in phantoms inside the hemisphere transducer array, no results in humans have been presented [14,15].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of an MRI receive head coil for use in transcranial MR guided focused ultrasound for functional neurosurgery

Bitton

Sheingaouz

Assif

et al. 2021

International Journal of Hyperthermia

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Background: Trans-cranial MR guided focused ultrasound (tcMRgFUS) ablation targets are <5mm from critical neurological structures, creating a need for improved MR imaging and thermometry. The purpose of this study was to evaluate the performance of a dual-channel radiofrequency receive-only head coil designed specifically for integrated use in tcMRgFUS. Methods: Imaging used a 3 T MRI and the ExAblate Neuro System (INSIGHTEC Inc., Israel). Sensitivity maps determined receive-only coil uniformity. The head coil was compared to the volume body coil at the level of the thalamus using 1) T2-weighted imaging and 2) multi-echo MR thermometry of volunteers in the transducer helmet. Thermal sonications (40 W, 24s) were acquired in a heating phantom. Thermal maps in were constructed to evaluate temperature uncertainty, focal heating, and temperature evolution. Results: The normalized signal intensity showed up to a 35% variation. On T2wFSE images the SNR with the head coil is improved by 4x in the axial plane, and 3x in sagittal and coronal planes. The head coil provided better visualization of the thalamus and globus pallidus (axial), and of the anterior/ posterior commissure, and brain stem/cerebellum (sagittal) compared to the body coil. MR thermometry showed a 4x gain in SNR in the thalamus. Thermometry showed a preserved focal spot with 20 C temperature rise. The average temperature uncertainty (mean ± std) was reduced from r T ¼ 0.96 C ± 0.55 C for the body coil to r T ¼ 0.41 C ± 0.24 C for the head coil. Conclusions: Greater SNR from the dual-channel head coil provides access to better treatment day visualization for treatment planning and higher precision intra-operative thermometry.

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Section: Introductionmentioning

confidence: 99%

Evaluation of an MRI receive head coil for use in transcranial MR guided focused ultrasound for functional neurosurgery

Bitton

Sheingaouz

Assif

et al. 2021

International Journal of Hyperthermia

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Technical Note: Effect of transducer position and ground plane configuration on image quality in MR‐guided focused ultrasound therapies

et al. 2020

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PurposeTo evaluate the effect of a focused ultrasound transducer position and ground plane configuration on magnetic resonance image quality.MethodsThe 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.ResultsBoth 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.ConclusionsAdvances 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.

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Contactless Thermometry by MRI and MRS: Advanced Methods for Thermotherapy and Biomaterials

Lutz¹,

Bernard²

2020

iScience

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Control of temperature variation is of primordial importance in particular areas of biomedicine. In this context, medical treatments such as hyperthermia and cryotherapy, but also the development and use of hydrogel-based biomaterials are of particular concern. To enable accurate temperature measurement without perturbing or even destroying the biological tissue or material to be monitored, contactless thermometry methods are preferred. Among these, the most suitable are based on magnetic resonance imaging and spectroscopy (MRI, MRS). Here, we address the latest developments in this field as well as their current and anticipated practical applications. We highlight recent progress aimed at rendering MR thermometry faster and more reproducible, versatile and sophisticated, and provide our perspective on how these new techniques broaden the range of applications in medical treatments and biomaterial development by enabling insight into finer details of thermal behavior. Thus, these methods facilitate optimization of clinical and industrial heating and cooling protocols.

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Development of custom RF coils for use in a small animal platform for magnetic resonance-guided focused ultrasound hyperthermia compatible with a clinical MRI scanner

Abstract: Curiel (2018) Development of custom RF coils for use in a small animal platform for magnetic resonance-guided focused ultrasound hyperthermia compatible with a clinical MRI scanner,

Cited by 4 publications

References 40 publications

Evaluation of an MRI receive head coil for use in transcranial MR guided focused ultrasound for functional neurosurgery

Evaluation of an MRI receive head coil for use in transcranial MR guided focused ultrasound for functional neurosurgery

Technical Note: Effect of transducer position and ground plane configuration on image quality in MR‐guided focused ultrasound therapies

Contactless Thermometry by MRI and MRS: Advanced Methods for Thermotherapy and Biomaterials

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