Safely assessing radiofrequency heating potential of conductive devices using image‐based current measurements

Griffin, Gregory H.; Anderson, K.M.; Çelik, Haydar; Wright, Graham A.

doi:10.1002/mrm.25103

Cited by 33 publications

(49 citation statements)

References 31 publications

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“…For each image that was acquired, a fit to the phase artifact in the region of the wire was performed to quantify the induced RF current at the location of the image. The details of the algorithm that was applied to produce a quantitative current value have been previously described . Before executing the fit to the phase artifact, the image was masked to exclude any regions of low signal.…”

Section: Methodsmentioning

confidence: 99%

“…For each iteration, a noiseless artifact was generated, and normally distributed, independent, pseudorandom values with mean zero and standard deviation

σ = \frac{| B_{1} |^{2}}{S N R}

were added to the real and imaginary components on a pixel‐by‐pixel basis . The phase of this noisy image was then used as the input to the method presented previously to find a discrete current value . This analysis was performed for current magnitudes ranging from 10 to 500 mA, with

| B_{1} | = 1 μ

T and SNR values ranging from 1 to 20.…”

Section: Methodsmentioning

confidence: 99%

“…A potentially more robust approach was previously demonstrated in vitro . The aforementioned technique involved acquiring phase images using a stock gradient echo sequence, at several points along a linear conductor in a phantom in the scanner.…”

Section: Introductionmentioning

confidence: 99%

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Toward in vivo quantification of induced RF currents on long thin conductors

Griffin

Ramanan

Barry

et al. 2018

Magnetic Resonance in Med

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Section: Methodsmentioning

confidence: 99%

“…For each iteration, a noiseless artifact was generated, and normally distributed, independent, pseudorandom values with mean zero and standard deviation

σ = \frac{| B_{1} |^{2}}{S N R}

| B_{1} | = 1 μ

T and SNR values ranging from 1 to 20.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Toward in vivo quantification of induced RF currents on long thin conductors

Griffin

Ramanan

Barry

et al. 2018

Magnetic Resonance in Med

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“…66 The benefit of this approach is that it permits labelling of the device based on induced RF current distributions which could permit many scans that may be otherwise forbidden with labelling that is based on global SAR levels. 67 Furthermore, such measurements could be used to guide adjustments in acquisitions such as the use of transmit arrays described above.…”

Section: Imaging Toolsmentioning

confidence: 99%

Real‐time MRI guidance of cardiac interventions

Campbell-Washburn

Tavallaei

Pop

et al. 2017

Magnetic Resonance Imaging

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Cardiac MR is appealing to guide complex cardiac procedures because it is ionizing radiation free and offers flexible soft tissue contrast. Interventional cardiac MR promises to improve existing procedures and enable new ones for complex arrhythmias, as well as congenital and structural heart disease. Guiding invasive procedures demands faster image acquisition, reconstruction and analysis, as well as intuitive intra-procedural display of imaging data. Standard cardiac MR techniques such as 3D anatomical imaging, cardiac function and flow, parameter mapping and late-gadolinium enhancement can be used to gather valuable clinical data at various procedural stages. Rapid intraprocedural image analysis can extract and highlight critical information about interventional targets and outcomes. In some cases, real-time interactive imaging is used to provide a continuous stream of images displayed to interventionalists for dynamic device navigation. Alternatively, devices are navigated relative to a roadmap of major cardiac structures generated through fast segmentation and registration. Interventional devices can be visualized and tracked throughout a procedure with specialized imaging methods. In a clinical setting, advanced imaging must be integrated with other clinical tools and patient data. In order to perform these complex procedures, interventional cardiac MR relies on customized equipment, such as interactive imaging environments, in-room image display, audio communication, hemodynamic monitoring and recording systems, and electroanatomical mapping and ablation systems. Operating in this sophisticated environment requires coordination and planning. This review will provide an overview of the imaging technology used in MRI-guided cardiac interventions. Specifically, this review will outline clinical targets, standard image acquisition and analysis tools, and the integration of these tools into clinical workflow.

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“…This reciprocal approach will be utilized alongside, with the possibility to image currents with MRI techniques to determine the TF of an implant in a single measurement. The current‐carrying implant, excited at the tip by a coax cable, is used as a transceive antenna during the MRI experiment.…”

Section: Theorymentioning

confidence: 99%