Guideline for Cardiovascular Magnetic Resonance Imaging from the Korean Society of Cardiovascular Imaging—Part 1: Standardized Protocol

Jo, Yeseul; Kim, Jeong Jae; Park, Chul Hwan; Lee, Jae Woo; Hur, Jee Hye; Yang, Dong Hyun; Lee, Bae-Young; Im, Dong Jin; Hong, Su Jin; Kim, Eun Young; Park, Eun‐Ah; Kim, Pan Ki; Yong, Hwan Seok

doi:10.22468/cvia.2019.00108

Cited by 6 publications

(11 citation statements)

References 58 publications

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“…The phantom consisted of LV, myocardium, and the right ventricle lumen (RV) with circular or elliptical shapes implemented by corresponding Fourier transforms in k-space. Assuming conditions mimicking cardiac diastolic phase, the phantom had transmural myocardial thickness of 1 cm and spatial resolution of 2.8 mm 2 , which translates to a myocardial thickness of 3.6 pixels. Twenty dynamics were generated to simulate the first pass of a contrast agent from RV through LV and myocardium.…”

Section: Numerical Phantommentioning

confidence: 99%

“…where x is normalized image intensity ranging from 0 to 1, with 1 being the highest intensity measured across all time frames. Since the mapping from RGB signal levels to luminance outputs is nonlinear for computer monitors, Equations [1] and [2] often do not result in an iso-luminant chromatic scale. Nevertheless, the resulting color scales exhibit a significantly reduced variation in luminance.…”

Section: Numerical Phantommentioning

confidence: 99%

“…2D, E), due to smaller difference in intensity between the LV and myocardium. Figure 3 shows the k-space windowed phantom images at the same time frames, but displayed using the two color scales defined as Equations [1] and [2]. The illusory dark band perceived in Figure 2 is eliminated due to the reduced luminance variation in the color maps used.…”

Section: Numerical Phantommentioning

confidence: 99%

“…5A, B; 9th time frame) and Figure 4E (Fig. 5D, E; 14th time frame) using two nearisoluminant color maps written as Equations [1] and [2]. Also shown are corresponding intensity profiles along six transmural segments (Fig.…”

Section: Dependence On Wall Location and Contrast Uptakementioning

confidence: 99%

“…Magnetic resonance (MR) contrast-enhanced myocardial perfusion imaging (MPI) can assess the extent and distribution of ischemia (1)(2)(3). In comparison to singlephoton emission CT or positron emission tomography, the established methods for clinical evaluation of myocardial perfusion, MR MPI offers superior spatial resolution with https://doi.org/10.3348/kjr.2019.0449…”

Section: Introductionmentioning

confidence: 99%

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Perceived Dark Rim Artifact in First-Pass Myocardial Perfusion Magnetic Resonance Imaging Due to Visual Illusion

Shin

Nayak

2020

Korean J Radiol

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Objective: To demonstrate that human visual illusion can contribute to sub-endocardial dark rim artifact in contrast-enhanced myocardial perfusion magnetic resonance images. Materials and Methods: Numerical phantoms were generated to simulate the first-passage of contrast agent in the heart, and rendered in conventional gray scale as well as in color scale with reduced luminance variation. Cardiac perfusion images were acquired from two healthy volunteers, and were displayed by the same gray and color scales used in the numerical study. Before and after k-space windowing, the left ventricle (LV)-myocardium boarders were analyzed visually and quantitatively through intensity profiles perpendicular the boarders. Results: k-space windowing yielded monotonically decreasing signal intensity near the LV-myocardium boarder in the phantom images, as confirmed by negative finite difference values near the board ranging-1.07 to-0.14. However, the dark band still appears, which is perceived by visual illusion. Dark rim is perceived in the in-vivo images after k-space windowing that removed the quantitative signal dip, suggesting that the perceived dark rim is a visual illusion. The perceived dark rim is stronger at peak LV enhancement than the peak myocardial enhancement, due to the larger intensity difference between LV and myocardium. In both numerical phantom and in-vivo images, the illusory dark band is not visible in the color map due to reduced luminance variation. Conclusion: Visual illusion is another potential cause of dark rim artifact in contrast-enhanced myocardial perfusion MRI as demonstrated by illusory rim perceived in the absence of quantitative intensity undershoot.

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Section: Numerical Phantommentioning

confidence: 99%

Section: Numerical Phantommentioning

confidence: 99%

Section: Numerical Phantommentioning

confidence: 99%

Section: Dependence On Wall Location and Contrast Uptakementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Perceived Dark Rim Artifact in First-Pass Myocardial Perfusion Magnetic Resonance Imaging Due to Visual Illusion

Shin

Nayak

2020

Korean J Radiol

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Phantom-based correction for standardization of myocardial native T1 and extracellular volume fraction in healthy subjects at 3-Tesla cardiac magnetic resonance imaging

et al. 2022

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Objectives To investigate the effect of the phantom-based correction method for standardizing myocardial native T1 and extracellular volume fraction (ECV) in healthy subjects. Methods Seventy-one healthy asymptomatic adult (≥ 20 years) volunteers of five different age groups (34 men and 37 women, 45.5 ± 15.5 years) were prospectively enrolled in three academic hospitals. Cardiac MRI including Modified Look - Locker Inversion recovery T1 mapping sequence was performed using a 3-Tesla system with a different type of scanner for each hospital. Native T1 and ECV were measured in the short-axis T1 map and analyzed for mean values of the 16 entire segments. The myocardial T1 value of each subject was corrected based on the site-specific equation derived from the T1 Mapping and ECV Standardization phantom. The global native T1 and ECV were compared between institutions before and after phantom-based correction, and the variation in native T1 and ECV among institutions was assessed using a coefficient of variation (CoV). Results The global native T1 value significantly differed between the institutions (1198.7 ± 32.1 ms, institution A; 1217.7 ± 39.9 ms, institution B; 1232.7 ± 31.1 ms, institution C; p = 0.002), but the mean ECV did not (26.6–27.5%, p = 0.355). After phantom-based correction, the global native T1 and ECV were 1289.7 ± 32.4 ms and 25.0 ± 2.7%, respectively, and CoV for native T1 between the three institutions decreased from 3.0 to 2.5%. The corrected native T1 value did not significantly differ between institutions (1284.5 ± 31.5 ms, institution A; 1296.5 ± 39.1 ms, institution B; 1291.3 ± 29.3 ms, institution C; p = 0.440), and neither did the ECV (24.4–25.9%, p = 0.078). Conclusions The phantom-based correction method can provide standardized reference T1 values in healthy subjects. Key Points • After phantom-based correction, the global native T1 of 16 entire myocardial segments on 3-T cardiac MRI is 1289.4 ± 32.4 ms, and the extracellular volume fraction was 25.0 ± 2.7% for healthy subjects. • After phantom - based correction was applied, the differences in the global native T1 among institutions became insignificant, and the CoV also decreased from 3.0 to 2.5%.

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LA-Net: A Multi-Task Deep Network for the Segmentation of the Left Atrium

Uslu

Varela

Boniface

et al. 2022

IEEE Trans. Med. Imaging

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Although atrial fibrillation (AF) is the most common sustained atrial arrhythmia, treatment success for this condition remains suboptimal. Information from magnetic resonance imaging (MRI) has the potential to improve treatment efficacy, but there are currently few automatic tools for the segmentation of the atria in MR images. In the study, we propose a LA-Net, a multi-task network optimised to simultaneously generate left atrial segmentation and edge masks from MRI. LA-Net includes cross attention modules (CAMs) and enhanced decoder modules (EDMs) to purposefully select the most meaningful edge information for segmentation and smoothly incorporate it into segmentation masks at multiple-scales. We evaluate the performance of LA-Net on two MR sequences: late gadolinium enhanced (LGE) atrial MRI and atrial short axis balanced steady state free precession (bSSFP) MRI. LA-Net gives Hausdorff distances of 12.43 mm and Dice scores of 0.92 on the LGE (STACOM 2018) dataset and Hausdorff distances of 17.41 mm and Dice scores of 0.90 on the bSSFP (inhouse) dataset without any post-processing, surpassing previously proposed segmentation networks, including U-Net and SEGANet. Our method allows automatic extraction of information about the LA from MR images, which can

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Guideline for Cardiovascular Magnetic Resonance Imaging from the Korean Society of Cardiovascular Imaging—Part 1: Standardized Protocol

Cited by 6 publications

References 58 publications

Perceived Dark Rim Artifact in First-Pass Myocardial Perfusion Magnetic Resonance Imaging Due to Visual Illusion

Perceived Dark Rim Artifact in First-Pass Myocardial Perfusion Magnetic Resonance Imaging Due to Visual Illusion

Phantom-based correction for standardization of myocardial native T1 and extracellular volume fraction in healthy subjects at 3-Tesla cardiac magnetic resonance imaging

LA-Net: A Multi-Task Deep Network for the Segmentation of the Left Atrium

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