Department of Radiology, Research Institute of Radiological Science, Yonsei University Health System, Seodaemun-gu, Seoul, South Korea.
Clin Radiol. 2010 Nov;65(11):916-23. doi: 10.1016/j.crad.2010.07.003.
To assess the utility of a T2*-weighted, multi-echo data imaging combination sequenced on superparamagnetic iron oxide (SPIO)-enhanced liver magnetic resonance imaging (MRI) using a 3 T system.
Fifty patients underwent SPIO-enhanced MRI at 3 T using T2*-weighted, single-echo, gradient-recalled echo (GRE) sequences [fast imaging with steady precession; repetition time (TR)/echo time (TE), 126 ms/9 ms; flip angle, 30°] and multi-echo GRE (multi-echo data image combination) sequences (TR/TE, 186 ms/9 ms; flip angle, 30°). Three radiologists independently reviewed the images in a random order. The sensitivity and accuracy for the detection of focal hepatic lesions (a total of 76 lesions in 33 patients; 48 solid lesions, 28 non-solid lesions) were compared by analysing the area under the receiver operating characteristic curves. Image artefacts (flow artefacts, susceptibility artefacts, dielectric artefacts, and motion artefacts), lesion conspicuity, and overall image quality were evaluated according to a four-point scale: 1, poor; 2, fair; 3, good; 4, excellent. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the lesions were compared.
Image artefacts were more frequent with single-echo GRE (p<0.05). The mean scale of image quality assessment for flow, susceptibility, dielectric, and motion artefacts were 2.76, 3.13, 3.42, and 2.89 with single-echo, respectively, compared with 3.47, 3.43, 3.47, and 3.39, respectively, with multi-echo GRE. There was no significant difference in lesion conspicuity between single-echo (3.15) and multi-echo (3.30) GRE sequences. The overall image quality was significantly (p<0.05) better with multi-echo (3.37) than with single-echo GRE (2.89). The mean SNR and CNR of the lesions were significantly (p<0.05) higher on multi-echo (79±23 and 128±59, respectively) images than on single-echo (38±11 and 102±44, respectively) images. Lesion detection accuracy and sensitivity were not significantly different between the two sequences. Mean accuracies and sensitivities were 0.864 and 0.785 for single-echo and 0.847 and 0.785 for multi-echo GRE, respectively.
At 3 T, the T2*-weighted, multi-echo data image combination sequence performs comparably to the T2*-weighted, single-echo GRE sequence for SPIO-enhanced MRI with good overall image quality and a decrease in undesired artefacts.
评估在 3T 系统上使用超顺磁性氧化铁（SPIO）增强磁共振成像（MRI）的 T2*-加权多回波数据成像组合序列的效用。
50 例患者在 3T 下进行 SPIO 增强 MRI 检查，采用 T2*-加权单回波梯度回波（GRE）序列[快速稳定进动；重复时间（TR）/回波时间（TE），126ms/9ms；翻转角，30°]和多回波 GRE（多回波数据图像组合）序列（TR/TE，186ms/9ms；翻转角，30°）。三位放射科医生以随机顺序独立评估图像。通过分析受试者工作特征曲线下的面积，比较两种序列检测局灶性肝病变（33 例患者共 76 个病变；48 个实性病变，28 个非实性病变）的敏感性和准确性。根据四点量表评估图像伪影（流伪影、磁化率伪影、介电伪影和运动伪影）、病变显示程度和整体图像质量：1，差；2，一般；3，好；4，优。比较病变的信噪比（SNR）和对比噪声比（CNR）。
单回波 GRE 图像的图像伪影更频繁（p<0.05）。与单回波 GRE 相比，多回波 GRE 中血流、磁化率、介电和运动伪影的平均图像质量评分分别为 2.76、3.13、3.42 和 2.89，分别为 3.47、3.43、3.47 和 3.39。两种序列检测病变的显示程度无显著差异（单回波 GRE 3.15，多回波 GRE 3.30）。多回波 GRE 的整体图像质量明显优于单回波 GRE（p<0.05）（3.37 比 2.89）。病变的平均 SNR 和 CNR 在多回波 GRE（分别为 79±23 和 128±59）图像上明显高于单回波 GRE（分别为 38±11 和 102±44）图像（p<0.05）。两种序列的病变检测准确性和敏感性无显著差异。单回波 GRE 的平均准确性和敏感性分别为 0.864 和 0.785，多回波 GRE 分别为 0.847 和 0.785。
在 3T 下，T2*-加权多回波数据图像组合序列在 SPIO 增强 MRI 中与 T2*-加权单回波 GRE 序列性能相当，具有良好的整体图像质量和减少不良伪影。
