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

Abstract

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; MRconditional) 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.

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

“…This study expands upon what is known regarding MRI in S‐ICD patients by examining the artifact patterns associated with S‐ICD devices in LGE imaging compared to other ICD types. Previous work has outlined the feasibility of imaging patients with S‐ICDs in general MRI examinations, with a case report describing the application of a WB LGE protocol in a patient with S‐ICD, and a more recent study outlining the overall safety and clinical utility in this population 9, 22, 23 . In particular, a study by Holtstiege et al, evaluated the efficacy of multiple pulse sequences in S‐ICD subjects for comprehensive aortic and left ventricular perfusion, function, and LGE imaging and found WB LGE did reduce artifact in 65% of subjects 9 .…”

“…Compared to conventional TV‐ICD systems, in which the pulse generator pocket is placed in the upper chest, the S‐ICD pulse generator pocket is typically in the left mid‐axillary line, with a lead tunneled in along the left subcostal margin. These intrinsic differences may implications for the quality of diagnostic cardiac MRI 9 …”

“…At present, little is known regarding the typical patterns of DRA and image quality in patients with S‐ICD and CRT‐D, compared to conventional TV‐ICD systems when using a standard LGE and WB LGE pulse sequences, although a recent study has shown a high prevalence of artifact with S‐ICD patients, which was reduced by using a WB LGE approach 9 …”

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

“…Fourth, our study included only four patients with S‐ICDs. The degree of image quality improvement with wideband LGEs compared with standard LGE might be even greater for patients with S‐ICDs, which are approximately twice as large as TV‐ICDs and implanted closer to the heart 35,36 . Fifth, because wideband LGE sequences produce approximately 90% of diagnostically interpretable myocardial segments, they provide a means to evaluate scar distribution in homogenous cohorts of CIED patients.…”

2021 Update on Safety of Magnetic Resonance Imaging: Joint Statement From Canadian Cardiovascular Society/Canadian Society for Cardiovascular Magnetic Resonance/Canadian Heart Rhythm Society

“…S-ICDs showed no significant adverse outcomes to patient or device during various MRI scans at 1.5 T. 24,25 In one study of 23 patients undergoing cardiac MRI, a permanent loss of the S-ICD beeper volume was observed in 52% of subjects, however, this was not believed to represent a major safety issue with current follow-up protocols. 25 In a phantom study 26 and a small cohort study of 15 patients 27 with leadless pacemakers undergoing MRI at 1.5 T and 3 T were evaluated and no adverse patient outcomes or device malfunctions were reported. Currently, only Micra (Medtronic, Fridley, MN) is available, which is MRI-conditional up to 3.0 T. Nanostim (Abbott, Chicago, IL) was recalled but there are still patients with these devices implanted.…”