基于分段回波平面成像的多层面同时读取技术加速下颌神经弥散张量成像：一项可行性研究。
Simultaneous multislice readout-segmented echo planar imaging for accelerated diffusion tensor imaging of the mandibular nerve: A feasibility study.
机构信息
Institute for Diagnostic and Interventional Radiology, Department of Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
Psychiatric University Hospital, Department of Psychiatry, Psychotherapy and Psychosomatics, University of Zurich, Zurich, Switzerland.
出版信息
J Magn Reson Imaging. 2017 Sep;46(3):663-677. doi: 10.1002/jmri.25603. Epub 2017 Jan 9.
PURPOSE
To assess the feasibility of diffusion tensor imaging (DTI) using simultaneous multislice (SMS) acquisition with blipped controlled aliasing in parallel imaging (CAIPI) for accelerated readout-segmented echo planar imaging (rs-EPI) of the mandibular nerves. DTI of the mandibular nerves using EPI is challenging due to susceptibility artifacts. Rs-EPI is less prone to artifacts but associated with longer scan durations.
MATERIALS AND METHODS
Eight asymptomatic volunteers were imaged at 3T using a 64-channel head/neck coil. Conventional, 2-fold (2xSMS) and 3-fold (3xSMS) slice-accelerated rs-EPI sequences were acquired. Tractography of the mandibular nerves was performed. Signal-to-noise ratio (SNR), fractional anisotropy (FA), mean diffusivity (MD), and number of tracts were calculated. Artifacts were evaluated qualitatively on Likert scales. Parameters were compared statistically. Clinical feasibility of 2xSMS rs-EPI was tested in four patients.
RESULTS
SNR was similar for conventional (mean ± SD; 8.55 ± 3.90) and 2xSMS rs-EPI (7.83 ± 3.15) but lower for 3xSMS rs-EPI (5.42 ± 2.93; analysis of variance, P = 0.004). FA was similar for all sequences (rs-EPI, 0.42 ± 0.08; 2xSMS rs-EPI, 0.43 ± 0.08; 3xSMS rs-EPI, 0.44 ± 0.06), while 3xSMS rs-EPI showed lower MD (rs-EPI, 0.0015 ± 0.0003; 2xSMS rs-EPI, 0.0014 ± 0.0001; 3xSMS rs-EPI, 0.0013 ± 0.0003) and lower number of tracts (rs-EPI, 66.56 ± 51.31; 2xSMS rs-EPI, 65.75 ± 55.40; 3xSMS rs-EPI, 37.93 ± 52.42) compared to rs-EPI and 2xSMS rs-EPI. Additionally, 2xSMS rs-EPI was feasible in four clinical patients and provided robust imaging results.
CONCLUSION
2xSMS rs-EPI yielded similar SNR, FA, and MD values compared to conventional rs-EPI at reduced scan time and is feasible in clinical patients. These findings suggest the potential clinical applicability of rs-EPI for DTI of the mandibular nerve.
LEVEL OF EVIDENCE
2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:663-677.
目的
使用带闪烁控制反转的并行采集（CAIPI）的同时多层采集（SMS）评估扩散张量成像（DTI）在加速读取分段回波平面成像（rs-EPI）下颌神经中的可行性。由于磁化率伪影，使用 EPI 对下颌神经进行 DTI 具有挑战性。rs-EPI 不易产生伪影，但扫描时间较长。
材料和方法
在 3T 上使用 64 通道头/颈线圈对 8 名无症状志愿者进行成像。采集了常规、2 倍（2xSMS）和 3 倍（3xSMS）切片加速 rs-EPI 序列。对下颌神经进行了轨迹成像。计算了信噪比（SNR）、各向异性分数（FA）、平均扩散系数（MD）和轨迹数量。使用李克特量表对伪影进行定性评估。对参数进行统计学比较。在 4 名患者中测试了 2xSMS rs-EPI 的临床可行性。
结果
常规（平均值±标准差；8.55±3.90）和 2xSMS rs-EPI 的 SNR 相似（分析方差，P=0.004），但 3xSMS rs-EPI 的 SNR 较低（5.42±2.93）。所有序列的 FA 均相似（rs-EPI，0.42±0.08；2xSMS rs-EPI，0.43±0.08；3xSMS rs-EPI，0.44±0.06），而 3xSMS rs-EPI 的 MD 较低（rs-EPI，0.0015±0.0003；2xSMS rs-EPI，0.0014±0.0001；3xSMS rs-EPI，0.0013±0.0003）和轨迹数量较少（rs-EPI，66.56±51.31；2xSMS rs-EPI，65.75±55.40；3xSMS rs-EPI，37.93±52.42）。此外，与 rs-EPI 和 2xSMS rs-EPI 相比，2xSMS rs-EPI 在减少扫描时间的同时还提供了相似的 SNR、FA 和 MD 值，并且在临床患者中是可行的。
结论
2xSMS rs-EPI 与常规 rs-EPI 相比，在减少扫描时间的同时提供了相似的 SNR、FA 和 MD 值，并且在临床患者中是可行的。这些发现表明 rs-EPI 对下颌神经 DTI 的潜在临床适用性。
证据水平
2 技术功效：第 1 阶段 J. MAGN. RESON. IMAGING 2017;46:663-677.
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