Off-resonance insensitive LGE MRI for imaging ventricular scar without image artifacts induced by cardiac devices

Background Late gadolinium enhanced (LGE) MRI is the gold standard test for non-invasive detection of myocardial scar. Many VT ablation candidates who would derive benefit from LGE MRI do not undergo cardiac MRI largely due to image artifacts generated by cardiac devices. A recent study reported improved LGE MRI for patients with implantable cardiac devices using a custom-made wideband adiabatic inversion-recovery (IR) pulse [1]. The purpose of this study was to implement off-resonanceinsensitive LGE MRI based on commercially available IR pulse for imaging ventricular scar without image artifacts induced by cardiac devices. Methods We implemented cardiac-device-insensitive LGE MRI by modifying a commercially available adiabatic IR pulse (Siemens_external_RF_file:IR10240H180.IR180_36B1_2) with the following parameters:b = 750radians/s, μ =1 0 (dimensionless), pulse duration = 6.1 ms. We designed the IR pulse to achieve B1 +o f 1050 Hz and 779 Hz at 1.5T and 3T, respectively, in order to achieve adiabaticity within the RF amplifier and SAR limits. Standard and wideband LGE MRI pulse sequences were evaluated in phantoms and seven canines (with ICD placed 10 cm away from the heart) with myocardial lesions created by radio-frequency ablation at 3T, as well as in one patient with ICD at 1.5T. Both LGE MRI pulse sequences used the same standard imaging parameters, except for the IR pulse. Two readers independently evaluated the image quality(1-5;worst-best) and artifact level(1-5;least-most) using a 5-point Likert scale. After administration of TTC, animals were euthanized for heart removal and gross pathology.