Wideband myocardial perfusion pulse sequence for imaging patients with a cardiac implantable electronic device

Purpose: To develop a wideband cardiac perfusion pulse sequence and test whether it is capable of suppressing image artifacts in patients with a cardiac implantable electronic device (CIED), while not exceeding the specific absorption rate (SAR) limit (2.0 W/kg). Methods: A wideband perfusion pulse sequence was developed by incorporating a wideband saturation pulse to achieve a good balance between saturation of magnetization and SAR. Clinical standard and wideband perfusion MRI scans were performed back-to-back in a randomized order on 16 patients with a CIED undergoing clinical cardiac MRI. Two expert readers graded the artifact intensity and extent on a segmental basis using a 5-point Likert scale, where significant artifact was defined by a composite score. The variance in myocardial signal before tissue-enhancement was analyzed to quantify artifact-intensity. Whole-body SAR values computed by the MR scanner were read from the DICOM header. Either a paired t-test or Wilcoxon signed-rank test was performed to compare two groups. Results: While the mean whole-body SAR for a single-slice wideband perfusion scan (0.38 +/- 0.08 W/kg) was significantly (P < 0.05) higher than for a single-slice standard perfusion scan (0.11 +/- 0.03 W/kg), it was 81% below 2.0 W/kg. The mean variance in myocardial signal before tissue-enhancement was significantly (P < 0.001) higher for standard (422.6 +/- 306.6 au) than wideband (107.0 +/- 60.9 au). Among 105 myocardial segments, standard produced 19 segments (18%) that were deemed to have significant artifacts, whereas wideband produced only 3 segments (3%). Conclusion: A wideband perfusion pulse sequence is capable of suppressing image artifacts induced by a CIED while not exceeding SAR at 2.0 W/kg.