Characterization and evaluation of tissue-mimicking gelatin phantoms for use with MRgFUS

Farrer, Alexis; Odéen, Henrik; Bever, Joshua de; Coats, Brittany; Parker, Dennis L.; Payne, Allison; Christensen, Douglas A.

doi:10.1186/s40349-015-0030-y

Cited by 106 publications

(103 citation statements)

References 44 publications

(33 reference statements)

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“…The proposed MW-AM imaging method was tested using two tissue mimicking phantoms that were fabricated described previously [16]. Phantom 1 had a 7-mm-diameter wall-less flow cell that was approximately 5 cm deep and centered laterally.…”

Section: Methodsmentioning

confidence: 99%

Improved Contrast-Enhanced Ultrasound Imaging With Multiplane-Wave Imaging

Gong

Song

Chen

2018

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Contrast-enhanced ultrasound (CEUS) imaging has great potential for use in new ultrasound clinical applications such as myocardial perfusion imaging and abdominal lesion characterization. In CEUS imaging, contrast agents (i.e., microbubbles) are used to improve contrast between blood and tissue because of their high nonlinearity under low ultrasound pressure. However, the quality of CEUS imaging sometimes suffers from a low signal-to-noise ratio (SNR) in deeper imaging regions when a low mechanical index (MI) is used to avoid microbubble disruption, especially for imaging at off-resonance transmit frequencies. In this paper, we propose a new strategy of combining CEUS sequences with the recently proposed multiplane wave (MW) compounding method to improve the SNR of CEUS in deeper imaging regions without increasing MI or sacrificing frame rate. The MW-CEUS method emits multiple Hadamard-coded CEUS pulses in each transmission event (i.e., pulse-echo event). The received echo signals first undergo fundamental bandpass filtering (i.e., the filter is centered on the transmit frequency) to eliminate the microbubble’s second harmonic signals because they cannot be encoded by pulse inversion. The filtered signals are then Hadamard decoded and re-aligned in fast time to recover the signals as they would have been obtained using classic CEUS pulses, followed by designed recombination to cancel the linear tissue responses. The MW-CEUS method significantly improved contrast-to-tissue ratio (CTR) and signal-to-noise ratio (SNR) of CEUS imaging by transmitting longer coded pulses. The image resolution was also preserved. The microbubble disruption ratio and motion artifacts in MW-CEUS were similar to those of classic CEUS imaging. In addition, the MW-CEUS sequence can be adapted to other transmission coding formats. These properties of MW-CEUS can potentially facilitate CEUS imaging for many clinical applications, especially assessing deep abdominal organs or the heart.

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Section: Methodsmentioning

confidence: 99%

Improved Contrast-Enhanced Ultrasound Imaging With Multiplane-Wave Imaging

Gong

Song

Chen

2018

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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“…In this study, a homogenous medium (gelatin-based phantom (31)) is used to validate this estimation technique. The 3D segmented model therefore consists of water and phantom domains, and phantom acoustic absorption and speed of sound are simultaneously estimated within the optimization routine.…”

Section: Methodsmentioning

confidence: 99%

“…Four variations of a tissue-mimicking gelatin phantom were fabricated to model a range of acoustic properties observed in soft tissue by varying the concentration of evaporated milk (31). These phantoms (179 ml, 7-cm height, and 5.7-cm diameter) contained 11.1% porcine gelatin powder (250-bloom ballistics gelatin, Vyse Gelatin Co., Schiller Park, IL, USA), 0.44% powder preservative (Dowacil, Dow Chemical Co., Midland, MI, USA), and 10%, 30%, 50%, or 70% by volume evaporated milk (Nestlé Carnation Evaporated Milk: Vitamin D added, 6.3% fat), with the remaining volume consisting of deionized water.…”

Section: Methodsmentioning

confidence: 99%

“…The through-transmission set-up included a deionized water tank containing a 1-MHz fundamental frequency ultrasound transducer (Panametrics-NDT, V314, Watham, MA, USA) and a hydrophone (ONDA, HNR-0500, Sunnyvale, CA) to receive the transmission of ultrasound through the phantom sample. Speed of sound ( c ) and acoustic attenuation (∝) values were determined at four frequencies: 0.65, 1.05, 1.70, and 3.00 MHz according to calculations previously described in (31,34). The measurement was performed once on each phantom, for a total of three measurements per phantom type (n=3).…”

Section: Methodsmentioning

confidence: 99%

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Development and validation of a MRgHIFU non-invasive tissue acoustic property estimation technique

Johnson

Dillon

Odéen

et al. 2016

International Journal of Hyperthermia

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MR-guided high-intensity focused ultrasound (MRgHIFU) non-invasive ablative surgeries have advanced into clinical trials for treating many pathologies and cancers. A remaining challenge of these surgeries is accurately planning and monitoring tissue heating in the face of patient-specific and dynamic acoustic properties of tissues. Currently, non-invasive measurements of acoustic properties have not been implemented in MRgHIFU treatment planning and monitoring procedures. This methods-driven study presents a technique using MR temperature imaging (MRTI) during low-temperature HIFU sonications to non-invasively estimate sample-specific acoustic absorption and speed of sound values in tissue-mimicking phantoms. Using measured thermal properties, specific absorption rate (SAR) patterns are calculated from the MRTI data and compared to simulated SAR patterns iteratively generated via the Hybrid Angular Spectrum (HAS) method. Once the error between the simulated and measured patterns is minimized, the estimated acoustic property values are compared to the true phantom values obtained via an independent technique. The estimated values are then used to simulate temperature profiles in the phantoms, and compared to experimental temperature profiles. This study demonstrates that trends in acoustic absorption and speed of sound can be non-invasively estimated with average errors of 21% and 1%, respectively. Additionally, temperature predictions using the estimated properties on average match within 1.2 °C of the experimental peak temperature rises in the phantoms. The positive results achieved in tissue-mimicking phantoms presented in this study indicate that this technique may be extended to in vivo applications, improving HIFU sonication temperature rise predictions and treatment assessment.

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“…The gelatin phantoms had a concentration of 5% weight (wt) powder in water, corresponding to a stiffness of 4.6 kPa, which was measured using an universal testing machine (Zwick/Roell Z005, Germany). This value roughly corresponds to the stiffness of brain tissue (0.5-6.0 kPa) 29 . For all experimental trials, we selected a constant forward speed of 1 mm/s and a theoretical travel distance equal to 120 mm.…”

Section: Methodsmentioning

confidence: 99%

Design and evaluation of a wasp-inspired steerable needle

et al. 2017

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Flexible steerable needles can follow complex curved paths inside the human body. In a previous work, we developed a multiple-part steerable needle prototype with a diameter of 1.2 mm, inspired by the ovipositor of parasitoid wasps. The needle consisted of seven nickel-titanium longitudinally aligned wires held together at the tip by a cylindrical ring with seven holes. The steerability of the needle was evaluated in a gelatin phantom and was found to be lower than that of other steerable needles in the literature. One possible cause of this limited steerability is that during motion the wires tend to separate from each other (i.e., bifurcate). Our aim here was to reduce bifurcation in order to increase the steering curvature of the needle, while keeping the diameter around 1.5 mm, and thus compatible with needles used in medical practice. To achieve that, we changed the shape of the ring from cylindrical to conical. We evaluated the steering performance in gelatin, using the conical ring in two configurations: (1) with the apex of the cone towards the needle tip, so that the wires converge, thus expected to reduce bifurcation, (2) with the apex of the cone placed towards the needle base, so that the wires diverge, thus expected to magnify bifurcation. Results showed that the diverging ring generated larger steering curvatures. We can conclude that reducing the bifurcation of the wires is not enough for increasing the steering curvature and that inducing this same phenomenon instead could actually lead to higher curvatures.

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Characterization and evaluation of tissue-mimicking gelatin phantoms for use with MRgFUS

Cited by 106 publications

References 44 publications

Improved Contrast-Enhanced Ultrasound Imaging With Multiplane-Wave Imaging

Improved Contrast-Enhanced Ultrasound Imaging With Multiplane-Wave Imaging

Development and validation of a MRgHIFU non-invasive tissue acoustic property estimation technique

Design and evaluation of a wasp-inspired steerable needle

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