Wideband LGE MRI permits unobstructed viewing of myocardial scarring in a patient with an MR-conditional subcutaneous implantable cardioverter-defibrillator

SCMR expert consensus statement for cardiovascular magnetic resonance of patients with a cardiac implantable electronic device

Cardiovascular magnetic resonance (CMR) is a proven imaging modality for informing diagnosis and prognosis, guiding therapeutic decisions, and risk stratifying surgical intervention. Patients with a cardiac implantable electronic device (CIED) would be expected to derive particular benefit from CMR given high prevalence of cardiomyopathy and arrhythmia. While several guidelines have been published over the last 16 years, it is important to recognize that both the CIED and CMR technologies, as well as our knowledge in MR safety, have evolved rapidly during that period. Given increasing utilization of CIED over the past decades, there is an unmet need to establish a consensus statement that integrates latest evidence concerning MR safety and CIED and CMR technologies. While experienced centers currently perform CMR in CIED patients, broad availability of CMR in this population is lacking, partially due to limited availability of resources for programming devices and appropriate monitoring, but also related to knowledge gaps regarding the risk-benefit ratio of CMR in this growing population. To address the knowledge gaps, this SCMR Expert Consensus Statement integrates consensus guidelines, primary data, and opinions from experts across disparate fields towards the shared goal of informing evidenced-based decision-making regarding the risk-benefit ratio of CMR for patients with CIEDs.

Impact of Wideband Late Gadolinium Enhancement Cardiac Magnetic Resonance Imaging on Device-Related Artifacts in Different Implantable Cardioverter-Defibrillator Types

BACKGROUND

Late gadolinium enhancement (LGE) imaging in patients with implantable cardioverter-defibrillators (ICD) is limited by device-related artifacts (DRA). The use of wideband (WB) LGE protocols improves LGE images, but their efficacy with different ICD types is not well known.

PURPOSE

To assess the effects of WB LGE imaging on DRA in different non-MR conditional ICD subtypes.

STUDY TYPE

Retrospective.

POPULATION

A total of 113 patients undergoing cardiac magnetic resonance imaging with three ICD subtypes: transvenous (TV-ICD, N = 48), cardiac-resynchronization therapy device (CRT-D, N = 48), and subcutaneous (S-ICD, N = 17).

FIELD STRENGTH/SEQUENCE

5 T scanner, standard LGE, and WB LGE imaging with a phase-sensitive inversion recovery segmented gradient echo sequence.

ASSESSMENT

DRA burden was defined as the number of artifact-positive short-axis LGE slices as percentage of the total number of short-axis slices covering the left ventricle from based to apex, and was determined for WB and standard LGE studies for each patient. Additionally, artifact area on each slice was quantified.

STATISTICAL TESTS

Shapiro-Wilks, Kruskal-Wallis analysis of variance, Dunn tests with Bonferroni correction, and Mann-Whitney U-test.

RESULTS

In patients with TV-ICD, DRA burden was significantly reduced and nearly eliminated with WB LGE compared to standard LGE imaging (median [interquartile range]: 0 [0-7]% vs. 18 [0-50]%, P < 0.05), but WB imaging had less of an impact on DRA in the CRT-D (8 [0-23]% vs. 16 [0-45]%, p = 0.12) and S-ICD (60 [15-71]% vs. 67 [50-92]%, P = 0.09) patients. Residual DRA was significantly greater (P < 0.05) for S-ICD compared to other device types with WB LGE imaging, despite the generators of all three ICD types having similar proximity to the heart. The area of S-ICD associated DRA was smaller with WB LGE (P < 0.001) than with standard LGE imaging and the artifacts had different characteristics (dark signal void instead of a bright hyperenhancement artifact).

DATA CONCLUSION

Although WB LGE imaging reduced the burden of DRA caused by S-ICD, the residual artifact was greater than that observed with TV-ICD and CRT-D devices. Further developments are needed to better resolve S-ICD artifacts.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: STAGE: 5.

Evaluation of image quality of wideband single-shot late gadolinium-enhancement MRI in patients with a cardiac implantable electronic device

INTRODUCTION

While wideband segmented, breath-hold late gadolinium-enhancement (LGE) cardiovascular magnetic resonance (CMR) has been shown to suppress image artifacts associated with cardiac-implanted electronic devices (CIEDs), it may produce image artifacts in patients with arrhythmia and/or dyspnea. Single-shot LGE is capable of suppressing said artifacts. We sought to compare the performance of wideband single-shot free-breathing LGE against the standard and wideband-segmented LGEs in CIED patients.

METHODS AND RESULTS

We retrospectively identified all 54 consecutive patients (mean age: 61 ± 15 years; 31% females) with CIED who had undergone CMR with standard segmented, wideband segmented, and/or wideband single-shot LGE sequences as part of quality assurance for determining best clinical practice at 1.5 T. Two raters independently graded the conspicuity of myocardial scar or normal myocardium and the presence of device artifact level on a 5-point Likert scale (1: worst; 3: acceptable; 5: best). Summed visual score (SVS) was calculated as the sum of conspicuity and artifact scores (SVS ≥ 6 defined as diagnostically interpretable). Median conspicuity and artifact scores were significantly better for wideband single-shot LGE (F = 24.2, p < .001) and wideband-segmented LGE (F = 20.6, p < .001) compared to standard-segmented LGE. Among evaluated myocardial segments, 72% were deemed diagnostically interpretable-defined as SVS ≥ 6-for standard-segmented LGE, 89% were deemed diagnostically interpretable for wideband-segmented LGE, and 94% segments were deemed diagnostically interpretable for wideband single-shot LGE.

CONCLUSIONS

Wideband single-shot LGE and wideband-segmented LGE produced similarly improved image quality compared to standard LGE.

Clinical experience regarding safety and diagnostic value of cardiovascular magnetic resonance in patients with a subcutaneous implanted cardioverter/defibrillator (S-ICD) at 1.5 T

BACKGROUND

Cardiovascular magnetic resonance (CMR) studies in patients with implanted cardioverter/defibrillators (ICD) are increasingly required in daily clinical practice. However, the clinical experience regarding the feasibility as well as clinical value of CMR studies in patients with subcutaneous ICD (S-ICD) is still limited. Besides safety issues, image quality and analysis can be impaired primarily due the presence of image artefacts associated with the generator.

METHODS

Twenty-three patients with an implanted S-ICD (EMBLEM, Boston Scientific, Marlborough, Massachusetts, USA; MR-conditional) with suspected cardiomyopathy and/or myocarditis underwent multi-parametric CMR imaging. Studies were performed on a 1.5 T CMR scanner after device interrogation and comprised standard a) balanced steady state free precession cine, b) T2 weighted-edema, c) velocity-encoded cine flow, d) myocardial perfusion, e) late-gadolinium-enhancement (LGE)-imaging and f) 3D-CMR angiography of the aorta. In case of substantial artefacts, alternative CMR techniques such as spoiled gradient-echo cine-sequences and wide-band inversion-recovery LGE (wb-LGE) sequences were applied.

RESULTS

Successful CMR studies could be performed in all patients without any case of unexpected early termination or relevant technical complication other than permanent loss of the S-ICD system beeper volume in 52% of our patients. Assessment of cine-CMR images was predominantly impaired in the left ventricular (LV) anterior, lateral and inferior wall segments and a switch to spoiled gradient echo-based cine-CMR allowed an accurate assessment of cine-images in N = 17 (74%) patients with only limited artefacts. Hyperintensity artefacts in conventional LGE-images were predominantly observed in the LV anterior, lateral and inferior wall segments and image optimisation by use of the wb-LGE was helpful in 15 (65%) cases. Aortic flow measurements and 3D-CMR angiography were assessable in all patients Perfusion imaging artefacts precluded a meaningful assessment in at least one half of the patients. A benefit in clinical-decision making was documented in 17 (74%) patients in the present study.

CONCLUSION

Safe 1.5 T CMR imaging was possible in all patients with an S-ICD, though the majority had permanent loss of the S-ICD beeper volume. Achieving good image quality may be challenging in some patients - particularly for perfusion imaging. Using spoiled gradient echo-based cine-sequences and wb-LGE sequences may help to reduce the extent of artefacts, thereby allowing accurate cardiac assessment. Thus, 1.5 T CMR studies should not be withhold in patients with S-ICD for safety concerns and/or fear of extensive imaging artefacts precluding successful image analysis.