Wideband cardiac magnetic resonance for myocardial tissue characterization in patients with implantable cardioverter defibrillators (ICDs): comment on Patelet al.’s Impact of wideband cardiac magnetic resonance on diagnosis, decision-making, and outcomes in patients with ICD

This editorial refers to ‘Impact of wideband cardiac magnetic resonance on diagnosis, decision-making, and outcomes in patients with implantable cardioverter defibrillators’, by H.N. Patel et al., https://doi.org/10.1093/ehjci/jeac227. Late gadolinium-enhanced (LGE) cardiac magnetic resonance imaging (cMR) is a key technique for non-invasive myocardial tissue characterization and allows differential diagnosis1,2 and risk stratification3 of various ischaemic and non-ischaemic cardiomyopathies. It makes use of the unique fact that the gadolinium-based contrast agents have extracellular distribution volume and accumulate at equilibrium in higher concentrations in infarcted or fibrotic tissue than in normal myocardium. Gadolinium shortens the T1 time resulting in increased signal intensity of tissue with higher contrast concentration on T1-weighted imaging sequences. To maximize the contrast between normal and fibrotic tissue, the LGE approach nulls signal intensity in the normal myocardium using an inversion pulse. This makes abnormal fibrotic scar tissue stand out as bright hyperenhancement relative to normal tissue. However, the presence of metal from pacemakers and especially implantable cardioverter defibrillators (ICDs) induces an inhomogeneity of the magnetic field and a frequency shift of the inversion pulse, which will result in incorrect nulling of the normal myocardium.4 This can lead to artefacts that mimick the hyperenhancement of scar tissue. These artefacts occur most frequently in areas of the heart that are close to the device and may severely limit the quality of LGE images in patients with devices.5 Wideband LGE imaging4,6 uses an inversion pulse with increased bandwidth, which makes it less sensitive to such off-resonance artefacts. This ensures more accurate inversion of the signal and allows better quality LGE imaging with fewer artefacts than conventional LGE in patients with devices.7–10 However, it has not been shown whether the use of such wideband LGE-cMR would be important for clinical decision-making or prognosis in patients with ICDs.