High spatial resolution free-breathing 3D late gadolinium enhancement cardiac magnetic resonance imaging in ischaemic and non-ischaemic cardiomyopathy: quantitative assessment of scar mass and image quality

Background Late gadolinium enhancement (LGE) imaging is well validated for the diagnosis and quantification of myocardial infarction (MI). 2D LGE imaging involves multiple breath‐holds for acquisition of short‐axis slices to cover the left ventricle (LV). 3D LGE methods cover the LV in a single breath‐hold; however, breath‐hold duration is typically long with images susceptible to motion artifacts. Purpose/Hypothesis To assess a single breath‐hold 3D mDIXON LGE pulse sequence for image quality and quantitation of MI. Study Type Prospective. Population Ninety‐ two patients with prior MI. Field Strength/Sequence 1.5T cardiac MRI protocol using both conventional 2D phase sensitive inversion recovery and 3D mDIXON LGE imaging 10 minutes following contrast administration in random order to avoid bias. Assessment Data were analyzed qualitatively for image quality (three observers). Quantitative assessment of myocardial scar mass (full‐width half‐maximum), scar transmurality, and contrast‐to‐noise ratio measurements were performed. Time for 2D and 3D LGE imaging was recorded. Statistical Tests Paired Student's t‐test, Wilcoxon rank test, Cohen κ statistic, Pearson correlation, linear regression, and Bland–Altman analysis. Results Image quality scores were comparable between 3D and 2D LGE (1.4 ± 0.6 vs. 1.3 ± 0.5; P = 0.162). 3D LGE was associated with greater scar tissue mass (3D: 18.9 ± 17.5 g vs. 2D: 17.8 ± 16.2 g P = 0.03), although this difference was less pronounced when scar tissue was expressed as %LV mass (3D: 13.4 ± 9.9% vs. 2D: 12.7 ± 9.5% P = 0.07). For 3D vs. 2D scar mass there was a strong and significant positive correlation; Bland–Altman analysis showed mean mass bias of 1.1 g (95% confidence interval [CI]: –5.7 to 7.9). Segmental level agreement of scar transmurality between 3D and 2D LGE at the clinical viability threshold of 50% transmurality was excellent (κ = 0.870). 3D image acquisition (15.6 ± 1.4 sec) was just 5% of time required for 2D images (311.6 ± 43.2 sec) P < 0.0001. Data Conclusion Single breath‐hold 3D mDIXON LGE imaging allows quantitative assessment of MI mass and transmurality, with comparable image quality, in vastly shorter overall acquisition time compared with standard 2D LGE imaging. Level of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:1437–1445.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Feasibility study of a single breath‐hold, 3D mDIXON pulse sequence for late gadolinium enhancement imaging of ischemic scar

Foley

Fent

Garg

et al. 2018

“…Previous work has also explored using multi- RR TI-scout with iterative algorithms to estimate myocardial T 1 . 21 Our experience is that the T 1 -mapping based TI selection is more convenient and objective than the empirical method used at our center and others, 19 which is based on a one R-R TI-scout. First, our method does not need to visually assess the myocardial signal with respect to the blood signal across multiple TIs, a demanding step used by the TIscout to find the optimal TI.…”

Section: Discussionmentioning

confidence: 99%

“…Proper myocardial nulling is vital for assessment of 3D LGE, in part because 3D LGE is a 5–10‐minute scan, and is not readily repeated if nulling is found to be suboptimal. Although phase‐sensitive inversion recovery (PSIR) for 3D LGE has been developed, it doubles the scan time, and has not been commonly used for atrial imaging. Thus, myocardial nulling in 3D atrial LGE is completely dependent on the accuracy of TI provided by the 1 R‐R “TI‐scout” sequence .…”

mentioning

confidence: 99%

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REPAIRit: Improving Myocardial Nulling and Ghosting Artifacts of 3D Navigator‐Gated Late Gadolinium Enhancement Imaging During Arrhythmia

Huber

Latif

et al. 2018

Background Cardiac 3D navigator‐gated late gadolinium enhancement (LGE) imaging is important for assessment of left atrial fibrosis, but the image quality is often degraded due to arrhythmia. Purpose To investigate a novel 3D LGE sequence with improved myocardial nulling and reduced ghosting artifacts during arrhythmia. Study Type Prospective. Population Arrhythmia patients (n = 14). Sequence The proposed technique, REPAIRit (Regrowth Equalization Pulse for Arrhythmias in Inversion Recovery with automatic inversion time calculation), inserts a saturation pulse with a dynamic flip angle into the 3D LGE sequence to minimize arrhythmia‐induced signal fluctuations. Using ShMOLLI (shortened modified Look–Locker imaging) to estimate myocardial T1, REPAIRit automatically calculates the optimal inversion time (TI) based on Bloch equations. Assessment REPAIRit LGE and the standard LGE were compared with simulations, phantom imaging, and patient studies. Patient images were assessed quantitatively, based on ghost‐to‐noise ratio (GNR), blood signal‐to‐noise ratio (SNRb), myocardial signal‐to‐noise ratio (SNRm), and blood‐to‐myocardium contrast‐to‐noise ratio (CNR), and qualitatively on a 4‐point scale. Patients were subgrouped based on the presence of arrhythmia to assess the image quality difference. Statistical Tests The two LGE sequences were compared by Student's t‐test and Wilcoxon signed‐rank test. The two patient‐subgroups were compared using Welch's t‐test and Wilcoxon rank‐sum test. Results In 14 analyzed patients, REPAIRit LGE significantly lowered GNR (1.25 ± 0.41 vs. 1.42 ± 0.42, P = 0.04), reduced SNRm (1.90 ± 0.60 vs. 3.16 ± 1.66, P = 0.01), improved ghosting artifact scores (2.5 ± 0.6 vs. 2.2 ± 0.9, P = 0.03), myocardial nulling scores (2.7 ± 0.5 vs. 2.3 ± 0.7, P = 0.02), and atrial quality scores (2.8 ± 0.3 vs. 2.4 ± 0.8, P = 0.03) compared with the standard LGE. Comparing patients with arrhythmia (n = 6) to those without (n = 8) during the scan, the former had lower left ventricular (LV) myocardial T1s (430 ± 26 msec vs. 469 ± 39 msec, P = 0.06) but similar blood T1s (318 ± 55 msec vs. 316 ± 27 msec, P = 0.96), and significantly lower blood SNR (5.2 ± 1.8 vs. 9.2 ± 3.0, P = 0.01) and significantly worse image quality (P = 0.01 for REPAIRit and P = 0.03 for standard). Data Conclusion REPAIRit improves myocardial nulling and reduces ghosting artifacts of 3D LGE under arrhythmia. Level of Evidence: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:688–699.

Whole‐Heart High‐Resolution Late Gadolinium Enhancement: Techniques and Clinical Applications

Toupin

Pezel

Bustin

et al. 2021

In cardiovascular magnetic resonance, late gadolinium enhancement (LGE) has become the cornerstone of myocardial tissue characterization. It is widely used in clinical routine to diagnose and characterize the myocardial tissue in a wide range of ischemic and nonischemic cardiomyopathies. The recent growing interest in imaging left atrial fibrosis has led to the development of novel whole‐heart high‐resolution late gadolinium enhancement (HR‐LGE) techniques. Indeed, conventional LGE is acquired in multiple breath‐holds with limited spatial resolution: ~1.4–1.8 mm in plane and 6–8 mm slice thickness, according to the Society for Cardiovascular Magnetic Resonance standardized guidelines. Such large voxel size prevents its use in thin structures such as the atrial or right ventricular walls. Whole‐heart 3D HR‐LGE images are acquired in free breathing to increase the spatial resolution (up to 1.3 × 1.3 × 1.3 mm 3 ) and offer a better detection and depiction of focal atrial fibrosis. The downside of this increased resolution is the extended scan time of around 10 min, which hampers the spread of HR‐LGE in clinical practice. Initially introduced for atrial fibrosis imaging, HR‐LGE interest has evolved to be a tool to detect small scars in the ventricles and guide ablation procedures. Indeed, the detection of scars, nonvisible with conventional LGE, can be crucial in the diagnosis of myocardial infarction with nonobstructed coronary arteries, in the detection of the arrhythmogenic substrate triggering ventricular arrhythmia, and improve the confidence of clinicians in the challenging diagnoses such as the arrhythmogenic right ventricular cardiomyopathy. HR‐LGE also offers a precise visualization of left ventricular scar morphology that is particularly useful in planning ablation procedures and guiding them through the fusion of HR‐LGE images with electroanatomical mapping systems. In this narrative review, we attempt to summarize the technical particularities of whole‐heart HR‐LGE acquisition and provide an overview of its clinical applications with a particular focus on the ventricles. Evidence Level 2 Technical Efficacy Stage 2