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Review
. 2017 Jun;10(6):e005446.
doi: 10.1161/CIRCIMAGING.117.005446.

Low-Field Cardiac Magnetic Resonance Imaging: A Compelling Case for Cardiac Magnetic Resonance's Future

Orlando P Simonetti  1 , Rizwan Ahmad  2
Affiliations
Review

Low-Field Cardiac Magnetic Resonance Imaging: A Compelling Case for Cardiac Magnetic Resonance's Future

Orlando P Simonetti et al. Circ Cardiovasc Imaging. 2017 Jun.
No abstract available

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Figures

Figure 1
Figure 1
Impact of retrospectively lowering SNR on the image quality. A prospectively downsampled (R=3) segmented cine dataset was collected on a 1.5T scanner from a healthy volunteer. Acquisition parameters include: matrix size: 256×192; FOV: 380×285 mm2; TE/TR: 1.47/2.9 ms; slice thickness 8 mm; flip angle: 82°; bandwidth: 714 Hz/pixel; temporal resolution 47 ms; sampling pattern: VISTA; bSSFP-based prospectively triggered segmented sequence. Complex Gaussian noise was then added to simulate data at 1T, 0.5T and 0.35T field strengths. The image recovery was performed using SCoRe.
Figure 2
Figure 2
Cine images from the data collected on a 0.35T scanner. Three fully sampled segmented cine datasets (with three different imaging orientations: short-axis (SAX), 4-chamber (4CH), and 2-chamber (2CH)) were collected using the following parameters. Matrix size: 160×120 (SAX), 160×120 (4CH), 192×180 (2CH); FOV: 400×400 mm2 (SAX), 400×400 mm2 (4CH), 400×360 mm2 (2CH); TE/TR: 1.6/3.3 ms (SAX), TE/TR: 1.4/3.0 ms (4CH), TE/TR: 1.3/2.7 ms (SAX); slice thickness 8 mm; flip angle: 110°; bandwidth 558 Hz/pixel (SAX), bandwidth 789 Hz/pixel (4CH), bandwidth 1184 Hz/pixel (2CH), temporal resolution 40 ms (SAX), 45 ms (4CH), 40 ms (2CH); bSSFP-based prospectively triggered segmented sequence. For R=1, image recovery was based on the inverse Fourier transform of k-space data followed by sum-of-squares coil combine. For R=2, the data were retrospectively downsampled with VISTA, and the image recovery was based on SCoRe.
Figure 3
Figure 3
Phase-contrast MRI images from the data collected on a 0.35T scanner. A fully sampled dataset was acquired using the following parameters. Matrix size: 192×108; FOV: 350×262 mm2; TE/TR: 2.6/6.5 ms; slice thickness 8 mm; flip angle: 25°; bandwidth: 389 Hz/pixel; temporal resolution 52 ms; number of averages: 3; FLASH-based prospectively triggered segmented sequence. For R=1, image recovery was based on the inverse Fourier transform of k-space data followed by sum-of-squares coil combine. For R=2, the data were retrospectively downsampled with VISTA, and the image recovery was based on SCoRe. Note, for R=2, no averaging was employed.
Figure 4
Figure 4
Black blood images from the data collected on a 0.35T scanner. A fully sampled dataset was acquired using the following parameters. Matrix size: 192×114; FOV: 450×314 mm2; TE: 40 ms; TR: two RR intervals; echo-train length: 19; echo spacing 6 ms; slice thickness 6 mm; bandwidth: 389 Hz/pixel; turbo spin echo-based segmented sequence. For R=1, image recovery was based on the inverse Fourier transform of k-space data followed by sum-of-squares coil combine. For R=2, the data were retrospectively downsampled with VISTA, and the image recovery was based on SCoRe.
Figure 5
Figure 5
Impact of long TR on image quality. Two fully sampled datasets—one on a 1.5T scanner (top row) and one on 0.35T scanner (bottom row)—were collected. For the dataset collected on 1.5T, the following parameters were used. Matrix size: 192×132; FOV: 450×314 mm2; TE/TR: 4.6/9.2 ms; slice thickness 8 mm; flip angle: 110°; bandwidth: 134 Hz/pixel; temporal resolution 56 ms; bSSFP-based prospectively triggered segmented sequence. For the dataset collected on 0.35T, the following parameters were used. Matrix size: 192×126; FOV: 350×295 mm2; TE/TR: 4.6/9.3 ms; slice thickness 8 mm; flip angle: 110°; bandwidth: 130 Hz/pixel; temporal resolution 56 ms; bSSFP-based prospectively triggered segmented sequence. For R=1, image recovery was based on the inverse Fourier transform of k-space data followed by sum-of-squares coil combine. For R=2, the data were retrospectively downsampled with VISTA, and the image recovery was based on SCoRe.
See this image and copyright information in PMC

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