Ultrasound-driven cardiac MRI

Santini, Francesco; Gui, Laura; Lorton, Orane; P, Guillemin; Manasseh, Gibran; Roth, Myriam; Bieri, Oliver; Vallée, Jean‐Paul; Salomir, Rarès; Crowe, Lindsey A.

doi:10.1016/j.ejmp.2020.01.008

Cited by 5 publications

(4 citation statements)

References 24 publications

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“…To obtain the ultrasonography images, a specially designed 192-element MR-compatible abdominal ultrasound probe (IBMT, Fraunhofer, Sulzbach/Saar, Germany) was used with a clinical ultrasound scanner (Acuson Antares, Siemens Healthcare, Mountain View, CA; USA) to image cavitation effects during HIFU sonications. The transducer was designed to avoid interference from the MRI scanner during concurrent MRI and ultrasonography, with operating frequencies of 3-7.5 MHz and HIFU frequency at 1.031 MHz (37,62,63). The design reduced interference from the HIFU transducer and MRI system, allowing pulsed color Doppler and B-mode imaging of the perfused phantom.…”

Section: Ultrasonography and Perfusion Systemmentioning

confidence: 99%

Perfluorocarbon emulsion enhances MR-ARFI displacement and temperature in vitro: Evaluating the response with MRI, NMR, and hydrophone

Holman

Lorton

et al. 2023

Front. Oncol.

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Sonosensitive perfluorocarbon F8TAC18-PFOB emulsion is under development to enhance heating, increase thermal contrast, and reduce treatment times during focused ultrasound tumor ablation of highly perfused tissue. The emulsion previously showed enhanced heating during ex vivo and in vitro studies. Experiments were designed to observe the response in additional scenarios by varying focused ultrasound conditions, emulsion concentrations, and surfactants. Most notably, changes in acoustic absorption were assessed with MR-ARFI. Phantoms were developed to have thermal, elastic, and relaxometry properties similar to those of ex vivo pig tissue. The phantoms were embedded with varying amounts of F8TAC18-PFOB emulsion or lecithin-PFOB emulsion, between about 0.0-0.3% v:w, in 0.05% v:w increments. MR-ARFI measurements were performed using a FLASH-ARFI-MRT sequence to obtain simultaneous displacement and temperature measurements. A Fabry-Perot hydrophone was utilized to observe the acoustic emissions. Susceptibility-weighted imaging and relaxometry mapping were performed to observe concentration-dependent effects. 19F diffusion-ordered spectroscopy NMR was used to measure the diffusion coefficient of perfluorocarbon droplets in a water emulsion. Increased displacement and temperature were observed with higher emulsion concentration. In semi-rigid MR-ARFI phantoms, a linear response was observed with low-duty cycle MR-ARFI sonications and a mono-exponential saturating response was observed with sustained sonications. The emulsifiers did not have a significant effect on acoustic absorption in semi-rigid gels. Stable cavitation might also contribute to enhanced heating.

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Section: Ultrasonography and Perfusion Systemmentioning

confidence: 99%

Perfluorocarbon emulsion enhances MR-ARFI displacement and temperature in vitro: Evaluating the response with MRI, NMR, and hydrophone

Holman

Lorton

et al. 2023

Front. Oncol.

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“…Intercostal US imaging of the liver was performed with the US probe held in place by means of a strap and a custom made casting (Santini, Gui, Lorton, Guillemin, Manasseh, Roth, Bieri, Vallée, Salomir & Crowe 2020 1 and figure 3. Figure 1 shows the motion patterns of the clinical target volume (CTV) in superior-inferior (SI) direction for all data sets.…”

Section: Image Data Setsmentioning

confidence: 99%

“…Simultaneous abdominal US and 4DMRI of the lungs were acquired of five healthy volunteers under free respiration using two different 4DMRI sequences (Celicanin et al 2017. Intercostal US imaging of the liver was performed with the US probe held in place by means of a strap and a custom made casting (Santini et al 2020). B-mode US imaging was performed at 3.3 MHz and case-specific acoustic power.…”

Section: Image Data Setsmentioning

confidence: 99%

Liver-ultrasound-guided lung tumour tracking for scanned proton therapy: a feasibility study

et al. 2021

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Pencil beam scanned (PBS) proton therapy of lung tumours is hampered by respiratory motion and the motion-induced density changes along the beam path. In this simulation study, we aim to investigate the effectiveness of proton beam tracking for lung tumours both under ideal conditions and in conjunction with a respiratory motion model guided by real-time ultrasound imaging of the liver. Multiple-breathingcycle 4DMRIs of the thorax and abdominal 2D ultrasound images were acquired simultaneously for five volunteers. Deformation vector fields extracted from the 4DMRI, referred to as ground truth motion, were used to generate 4DCT(MRI) data sets of two lung cancer patients, resulting in 10 data sets with variable motion patterns. Given the 4DCT(MRI) and the corresponding ultrasound images as surrogate data, a patient-specific motion model was built. The model consists of an autoregressive model and Gaussian process regression for the temporal and spatial prediction, respectively. Two-field PBS plans were optimised on the reference CTs, and 4D dose calculations (4DDC) were used to simulate dose delivery for (a) unmitigated motion, (b) ideal 2D and 3D tracking (both beam adaption and 4DDC based on ground truth motion), and (c) realistic 2D and 3D tracking (beam adaption based on motion predictions, 4DDC on ground truth motion). Model-guided tracking retrieved clinically acceptable target dose homogeneity, as seen in a substantial reduction of the D5-D95 % compared to the non-mitigated simulation. Tracking in 2D and 3D resulted in a similar improvement of the dose homogeneity, as did ideal and realistic tracking simulations. In some

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“…The system was equipped with a specially designed MR-compatible US linear array transducer consisting of 192 elements (Fraunhofer IBMT, Sulzbach, Germany), equivalent to the Siemens' VF7-3 probe, with central frequency 5 MHz, and bandwidth 4 MHz. The US imaging probe was strapped to the subjects' abdomen and held in place using a home-built casting, as shown in the report of (Santini et al 2020). The probe was operated in B-mode at 3.3 MHz and covered a maximum field depth of 16 cm and an angular sector of up to 90 • .…”

Section: Data Acquisitionmentioning

confidence: 99%

Liver-ultrasound based motion modelling to estimate 4D dose distributions for lung tumours in scanned proton therapy

et al. 2020

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Motion mitigation strategies are crucial for scanned particle therapy of mobile tumours in order to prevent geometrical target miss and interplay effects. We developed a patient-specific respiratory motion model based on simultaneously acquired time-resolved volumetric MRI and 2D abdominal ultrasound images. We present its effects on 4D pencil beam scanned treatment planning and simulated dose distributions. Given an ultrasound image of the liver and the diaphragm, principal component analysis and Gaussian process regression were applied to infer dense motion information of the lungs. 4D dose calculations for scanned proton therapy were performed using the estimated and the corresponding ground truth respiratory motion; the differences were compared by dose difference volume metrics. We performed this simulation study on 10 combined CT and 4DMRI data sets where the motion characteristics were extracted from 5 healthy volunteers and fused with the anatomical CT data of two lung cancer patients. Median geometrical estimation errors below 2 mm for all data sets and maximum dose differences of V diff>5 % = 43.2 % and V diff>10 % = 16.3 % were found. Moreover, it was shown that abdominal ultrasound imaging allows to monitor organ drift. This study demonstrated the feasibility of the proposed ultrasound-based motion modelling approach for its application in scanned proton therapy of lung tumours.

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Ultrasound-driven cardiac MRI

Cited by 5 publications

References 24 publications

Perfluorocarbon emulsion enhances MR-ARFI displacement and temperature in vitro: Evaluating the response with MRI, NMR, and hydrophone

Perfluorocarbon emulsion enhances MR-ARFI displacement and temperature in vitro: Evaluating the response with MRI, NMR, and hydrophone

Liver-ultrasound-guided lung tumour tracking for scanned proton therapy: a feasibility study

Liver-ultrasound based motion modelling to estimate 4D dose distributions for lung tumours in scanned proton therapy

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