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Free-breathing 3D cardiac function with accelerated magnetization transfer prepared imaging

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3D cardiac MRI has long held promise for improved heart coverage, higher resolution, and reduced sensitivity to poor breath-hold reproducibility... However, its use has been limited by reduced blood pool to myocardium contrast for spoiled and balanced steady-state free precession (bSSFP) implementations... T2-preparation techniques are capable of increasing contrast but are unfortunately limited by lengthy preparation periods and resulting scan inefficiencies... An off-resonance RF pulse was interleaved with whole-heart, respiratory gated 3D radial SPGR sampling... Simulations and phantom scans were performed to optimize MT saturation (power, off-resonance, and frequency)... Phantom scans utilized 4% agar, fat, and doped water... After optimization, initial volunteer images were collected on a clinical 1.5T system (HDx, GE, Waukesha, WI) using: FOV = 64 × 32 × 32 cm3, 2.0 mm isotropic spatial resolution, TR/TE1/TE2 = 5.6/1.32/3.32 ms, α = 4°, free-breathing: scan time = 10 min, 50% acceptance window (bellows), number of projections = 39,000... Figure 1 shows images from phantom scans for a sweep of MT off-resonance frequencies and demonstrates the potential for simultaneous suppression of muscle (agar) and fat... In-vivo results are presented in Figure 2 for two reformats: vertical long axis in end-systole and end-diastole (left) and an end-systolic base to apex short axis stack (right)... The feasibility of a novel whole-heart functional cardiac acquisition using MT preparation with isotropic spatial resolution in a clinically reasonable scan time is presented... Further studies on optimization of acquisition parameters, including off-resonance frequency, number of projections, and acquired spatial resolution, will improve the applicability of the sequence for clinical situations.

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Left: Vertical long axis reformats in end-systole (top) and end-diastole (bottom) display excellent suppression of fat and muscle without off-resonance induced banding artifacts seen in bSSFP. Right: End-systolic short-axis stack from apex to base displays benefits of isotropic spatial resolution for retrospective reformatting of the entire heart in any orientation.
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Figure 2: Left: Vertical long axis reformats in end-systole (top) and end-diastole (bottom) display excellent suppression of fat and muscle without off-resonance induced banding artifacts seen in bSSFP. Right: End-systolic short-axis stack from apex to base displays benefits of isotropic spatial resolution for retrospective reformatting of the entire heart in any orientation.

Mentions: Figure 1 shows images from phantom scans for a sweep of MT off-resonance frequencies and demonstrates the potential for simultaneous suppression of muscle (agar) and fat. In-vivo results are presented in Figure 2 for two reformats: vertical long axis in end-systole and end-diastole (left) and an end-systolic base to apex short axis stack (right). Excellent blood pool to myocardium contrast and fat suppression are observed. Isotropic spatial resolution allows for retrospective whole-heart reformats in any orientation.


Free-breathing 3D cardiac function with accelerated magnetization transfer prepared imaging
Left: Vertical long axis reformats in end-systole (top) and end-diastole (bottom) display excellent suppression of fat and muscle without off-resonance induced banding artifacts seen in bSSFP. Right: End-systolic short-axis stack from apex to base displays benefits of isotropic spatial resolution for retrospective reformatting of the entire heart in any orientation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4044076&req=5

Figure 2: Left: Vertical long axis reformats in end-systole (top) and end-diastole (bottom) display excellent suppression of fat and muscle without off-resonance induced banding artifacts seen in bSSFP. Right: End-systolic short-axis stack from apex to base displays benefits of isotropic spatial resolution for retrospective reformatting of the entire heart in any orientation.
Mentions: Figure 1 shows images from phantom scans for a sweep of MT off-resonance frequencies and demonstrates the potential for simultaneous suppression of muscle (agar) and fat. In-vivo results are presented in Figure 2 for two reformats: vertical long axis in end-systole and end-diastole (left) and an end-systolic base to apex short axis stack (right). Excellent blood pool to myocardium contrast and fat suppression are observed. Isotropic spatial resolution allows for retrospective whole-heart reformats in any orientation.

View Article: PubMed Central - HTML

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

3D cardiac MRI has long held promise for improved heart coverage, higher resolution, and reduced sensitivity to poor breath-hold reproducibility... However, its use has been limited by reduced blood pool to myocardium contrast for spoiled and balanced steady-state free precession (bSSFP) implementations... T2-preparation techniques are capable of increasing contrast but are unfortunately limited by lengthy preparation periods and resulting scan inefficiencies... An off-resonance RF pulse was interleaved with whole-heart, respiratory gated 3D radial SPGR sampling... Simulations and phantom scans were performed to optimize MT saturation (power, off-resonance, and frequency)... Phantom scans utilized 4% agar, fat, and doped water... After optimization, initial volunteer images were collected on a clinical 1.5T system (HDx, GE, Waukesha, WI) using: FOV = 64 × 32 × 32 cm3, 2.0 mm isotropic spatial resolution, TR/TE1/TE2 = 5.6/1.32/3.32 ms, α = 4°, free-breathing: scan time = 10 min, 50% acceptance window (bellows), number of projections = 39,000... Figure 1 shows images from phantom scans for a sweep of MT off-resonance frequencies and demonstrates the potential for simultaneous suppression of muscle (agar) and fat... In-vivo results are presented in Figure 2 for two reformats: vertical long axis in end-systole and end-diastole (left) and an end-systolic base to apex short axis stack (right)... The feasibility of a novel whole-heart functional cardiac acquisition using MT preparation with isotropic spatial resolution in a clinically reasonable scan time is presented... Further studies on optimization of acquisition parameters, including off-resonance frequency, number of projections, and acquired spatial resolution, will improve the applicability of the sequence for clinical situations.

No MeSH data available.


Related in: MedlinePlus