Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL.
Division of Cardiology, Internal Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL.
Magn Reson Med. 2019 Feb;81(2):1219-1228. doi: 10.1002/mrm.27458. Epub 2018 Sep 9.
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).
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 prior to 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.
While the mean whole-body SAR for a single-slice wideband perfusion scan (0.38 ± 0.08W/kg) was significantly (p < 0.05) higher than for a single-slice standard perfusion scan (0.11 ± 0.03W/kg), it was 81% below 2.0 W/kg. The mean variance in myocardial signal prior to tissue-enhancement was significantly (p < 0.001) higher for standard (422.6 ± 306.6 a.u.) than wideband (107.0 ± 60.9 a.u.). Among 105 myocardial segments, standard produced 19 segments (18%) that were deemed to have significant artifacts, whereas wideband produced only 3 segments (3%).
A wideband perfusion pulse sequence is capable of suppressing image artifacts induced by a CIED while not exceeding SAR at 2.0 W/kg.
开发一种宽带心脏灌注脉冲序列，并测试其是否能够抑制心脏植入式电子设备（CIED）患者的图像伪影，同时不超过特定吸收率（SAR）限制（2.0 W/kg）。
通过合并宽带饱和脉冲来开发宽带灌注脉冲序列，以在磁化饱和和 SAR 之间取得良好的平衡。16 名接受临床心脏 MRI 的 CIED 患者以随机顺序先后进行临床标准和宽带灌注 MRI 扫描。两名专家读者使用 5 分李克特量表对节段性的伪影强度和范围进行分级，其中显著伪影的定义为综合评分。在组织增强之前分析心肌信号的方差以量化伪影强度。通过从 DICOM 头读取磁共振扫描仪计算的全身 SAR 值。使用配对 t 检验或 Wilcoxon 符号秩检验比较两组。
虽然单次宽带灌注扫描的平均全身 SAR（0.38 ± 0.08W/kg）明显（p < 0.05）高于单次标准灌注扫描（0.11 ± 0.03W/kg），但仍低于 2.0 W/kg 的 81%。在组织增强之前，心肌信号的平均方差在标准（422.6 ± 306.6 a.u.）中明显（p < 0.001）高于宽带（107.0 ± 60.9 a.u.）。在 105 个心肌节段中，标准产生了 19 个（18%）被认为具有显著伪影的节段，而宽带仅产生了 3 个节段（3%）。
宽带灌注脉冲序列能够抑制 CIED 引起的图像伪影，同时不超过 2.0 W/kg 的 SAR。
