Seeking a Widely Adoptable Practical Standard to Estimate Signal‐to‐Noise Ratio in Magnetic Resonance Imaging for Multiple‐Coil Reconstructions

Montin, Eros; Lattanzi, Riccardo

doi:10.1002/jmri.27816

Cited by 8 publications

(4 citation statements)

References 30 publications

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“…In addition, in order to evaluate the performance of the MR system, the SNR was evaluated on the images acquired by using MR scanner and the obtained results were compared with those found during previous QCs measurements. It was possible to observe a slight decrease in the SNR, such as not to invalidate the diagnosis, and not attributable to a malfunction of the coil; in fact, it can suffer from systematic errors due to scanner instabilities [35].…”

Section: Discussionmentioning

confidence: 99%

Radio Frequency MRI coils and safety: how infrared thermography can support quality assurance

Testagrossa

Ruello

Gurgone

et al. 2021

Egypt J Radiol Nucl Med

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Background The safety controls in Resonance Magnetic Imaging (MRI) diagnostic site are numerous and complex. Some of these are contained in international directives and regularly conducted by medical physics expert after acceptance tests, consisting of a series of checks, measurements, evaluations called quality controls (QCs) and made to guarantee the image quality of the equipment. In this context, ensuring that the coils are in proper operating conditions is important to prevent and reduce errors in use and to preserve patient safety. Results A study by thermography was conducted to evaluate temperature changes of MRI coils during Quality Control (QC), in order to prevent any problems for the patient due to Radio Frequency waves. This experiment involves use of a thermal camera to detect temperature variations during MRI scans using head and body coils of two different tomography 1.5 T and 3.0 T static magnetic field. Thermal camera was positioned inside the MRI room to acquire images every 15 s for all the scansions duration. The observations have shown a temperature increase only for body coil of 1.5 MRI tomography, whereas no significative temperature variation has occurred for the other coils under observation. This temperature increase was later related to a fault of such coil. Conclusions The authors believe this simple method useful as first approach, during routinely QCs, to verify coils functioning and so to avoid patient hazards and are preparing a methodological study about functioning of the coils with respect to their temperature variation.

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Section: Discussionmentioning

confidence: 99%

Radio Frequency MRI coils and safety: how infrared thermography can support quality assurance

Testagrossa

Ruello

Gurgone

et al. 2021

Egypt J Radiol Nucl Med

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“…To investigate the BraCoil's parallel imaging performance, we additionally calculated 2D SNR and g -factor maps with simulated acceleration factors of R = 2, 4, 6, and 8 in left-right (LR) and head-foot (HF) direction using open source Matlab code 55 , 56 also based on the pseudo multiple replica method. Resulting g -factor maps were plotted in a coronal slice for 3 differently sized breasts.…”

Section: Methodsmentioning

confidence: 99%

Panoramic Magnetic Resonance Imaging of the Breast With a Wearable Coil Vest

Obermann,

Nohava,

Frass-Kriegl

et al. 2023

Invest Radiol

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Background: Breast cancer, the most common malignant cancer in women worldwide, is typically diagnosed by x-ray mammography, which is an unpleasant procedure, has low sensitivity in women with dense breasts, and involves ionizing radiation. Breast magnetic resonance imaging (MRI) is the most sensitive imaging modality and works without ionizing radiation, but is currently constrained to the prone imaging position due to suboptimal hardware, therefore hampering the clinical workflow. Objectives: The aim of this work is to improve image quality in breast MRI, to simplify the clinical workflow, shorten measurement time, and achieve consistency in breast shape with other procedures such as ultrasound, surgery, and radiation therapy. Materials and Methods: To this end, we propose "panoramic breast MRI"-an approach combining a wearable radiofrequency coil for 3 T breast MRI (the "BraCoil"), acquisition in the supine position, and a panoramic visualization of the images. We demonstrate the potential of panoramic breast MRI in a pilot study on 12 healthy volunteers and 1 patient, and compare it to the state of the art. Results: With the BraCoil, we demonstrate up to 3-fold signal-to-noise ratio compared with clinical standard coils and acceleration factors up to 6 Â 4. Panoramic visualization of supine breast images reduces the number of slices to be viewed by a factor of 2-4. Conclusions: Panoramic breast MRI allows for high-quality diagnostic imaging and facilitated correlation to other diagnostic and interventional procedures. The developed wearable radiofrequency coil in combination with dedicated image processing has the potential to improve patient comfort while enabling more time-efficient breast MRI compared with clinical coils.

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“…The imaging parameters for SNR measurements were: repetition time (TR) = 200 ms, echo time (TE) = 5.8 ms, flip angle = 20°, voxel size = 1.6 × 1.6 × 10 mm 3 , pixel bandwidth (BW) = 130 Hz/pixel, and acquisition time (TA) = 38 s. The phantom SNR maps were reconstructed with 2.3 × 2.3 × 10 mm 3 voxels. Geometry factor maps 18 were calculated from the same data using methods described by Montin and Lattanzi 57 .…”

Section: Methodsmentioning

confidence: 99%

A flexible MRI coil based on a cable conductor and applied to knee imaging

Wang

Siddiq

Walczyk

et al. 2022

Sci Rep

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Flexible radiofrequency coils for magnetic resonance imaging (MRI) have garnered attention in research and industrial communities because they provide improved accessibility and performance and can accommodate a range of anatomic postures. Most recent flexible coil developments involve customized conductors or substrate materials and/or target applications at 3 T or above. In contrast, we set out to design a flexible coil based on an off-the-shelf conductor that is suitable for operation at 0.55 T (23.55 MHz). Signal-to-noise ratio (SNR) degradation can occur in such an environment because the resistance of the coil conductor can be significant with respect to the sample. We found that resonating a commercially available RG-223 coaxial cable shield with a lumped capacitor while the inner conductor remained electrically floating gave rise to a highly effective “cable coil.” A 10-cm diameter cable coil was flexible enough to wrap around the knee, an application that can benefit from flexible coils, and had similar conductor loss and SNR as a standard-of-reference rigid copper coil. A two-channel cable coil array also provided good SNR robustness against geometric variability, outperforming a two-channel coaxial coil array by 26 and 16% when the elements were overlapped by 20–40% or gapped by 30–50%, respectively. A 6-channel cable coil array was constructed for 0.55 T knee imaging. Incidental cartilage and bone pathologies were clearly delineated in T1- and T2-weighted turbo spin echo images acquired in 3–4 min with the proposed coil, suggesting that clinical quality knee imaging is feasible in an acceptable examination timeframe. Correcting for T1, the SNR measured with the cable coil was approximately threefold lower than that measured with a 1.5 T state-of-the-art 18-channel coil, which is expected given the threefold difference in main magnetic field strength. This result suggests that the 0.55 T cable coil conductor loss does not deleteriously impact SNR, which might be anticipated at low field.

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Seeking a Widely Adoptable Practical Standard to Estimate Signal‐to‐Noise Ratio in Magnetic Resonance Imaging for Multiple‐Coil Reconstructions

Cited by 8 publications

References 30 publications

Radio Frequency MRI coils and safety: how infrared thermography can support quality assurance

Radio Frequency MRI coils and safety: how infrared thermography can support quality assurance

Panoramic Magnetic Resonance Imaging of the Breast With a Wearable Coil Vest

A flexible MRI coil based on a cable conductor and applied to knee imaging

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