无直肠内线圈的前列腺神经血管束磁共振弥散张量成像：一项可行性研究。
Zoomed echo-planar diffusion tensor imaging for MR tractography of the prostate gland neurovascular bundle without an endorectal coil: a feasibility study.
机构信息
Department of Radiology, New York University School of Medicine, NYU Langone Medical Center, 660 1st Avenue, New York, NY, 10016, USA.
Siemens Healthcare, New York, NY, USA.
出版信息
Abdom Radiol (NY). 2016 May;41(5):919-25. doi: 10.1007/s00261-015-0587-5.
PURPOSE
The purpose of this study was to assess the feasibility of zoomed echo-planar imaging (EPI) diffusion tensor imaging (DTI) with 2-channel parallel transmission (pTx) for MR tractography of the periprostatic neurovascular bundle (NVB) without an endorectal coil, and to compare its performance to that of conventionally acquired DTI.
METHODS
8 healthy males (28.9 ± 4.6 years) underwent pelvic phased-array coil prostate MRI on a 3T system using both zoomed-EPI DTI (z-DTI) with 2-channel pTx and conventional single-shot spin-echo EPI DTI (c-DTI) acquisitions with 6 encoding directions and b-values of 0 and 1000 s/mm(2). Fractional anisotropy (FA) maps and tractography analysis incorporating 3D visualization of the NVB were performed from each acquisition. Fiber tract counts, estimated signal-to-noise ratio (eSNR), and image quality measures of the FA maps and NVB tractography were compared. Quantitative and image quality measures were compared using Wilcoxon signed rank tests.
RESULTS
3 of 8 subjects had no tracts detected with c-DTI acquisition, while all 8 had tracts detected with z-DTI. z-DTI acquisition yielded significantly more fiber tracts (c-DTI: 77 ± 116 tracts; z-DTI: 430 ± 228 tracts; p = 0.019) and higher eSNR (c-DTI: 2.9 ± 1.2; z-DTI: 13.17 ± 9.9; p = 0.014). Relative to c-DTI acquisitions, z-DTI FA maps showed significantly reduced artifact (p = 0.008) and reduced anatomic distortion of the prostate (p = 0.010), while z-DTI tractography showed significantly better overall visual quality (p = 0.011), tract symmetry (p = 0.010), tract coherence (p = 0.011), and subjective similarity to the actual NVB (p = 0.011).
CONCLUSION
Zoomed-EPI DTI acquisition for tractography of the prostate gland NVB improves quantitative and qualitative measures of image and tract fiber quality, allowing tractography of the NVB at 3T without using an endorectal coil.
目的
本研究旨在评估无直肠内线圈情况下，采用 2 通道并行传输（pTx）的放大回波平面成像（EPI）弥散张量成像（DTI）进行前列腺周神经血管束（NVB）磁共振追踪的可行性，并比较其与常规采集 DTI 的性能。
方法
8 名健康男性（28.9±4.6 岁）在 3T 系统上使用放大 EPI DTI（z-DTI）和常规单次激发自旋回波 EPI DTI（c-DTI）采集进行盆腔相控阵线圈前列腺 MRI 检查，分别采集 6 个方向的弥散张量图像，b 值为 0 和 1000 s/mm2。对每个采集的各向异性分数（FA）图和纳入 3D 可视化的 NVB 追踪分析。比较纤维束计数、估计信噪比（eSNR）以及 FA 图和 NVB 追踪的图像质量指标。使用 Wilcoxon 符号秩检验比较定量和图像质量指标。
结果
3 名受试者在 c-DTI 采集时未检测到纤维束，而 8 名受试者在 z-DTI 采集时均检测到纤维束。z-DTI 采集获得的纤维束明显更多（c-DTI：77±116 束；z-DTI：430±228 束；p=0.019），eSNR 也明显更高（c-DTI：2.9±1.2；z-DTI：13.17±9.9；p=0.014）。与 c-DTI 采集相比，z-DTI 的 FA 图显示明显减少的伪影（p=0.008）和前列腺的解剖变形减少（p=0.010），而 z-DTI 追踪显示明显更好的整体视觉质量（p=0.011）、束对称性（p=0.010）、束连贯性（p=0.011）和与实际 NVB 的主观相似性（p=0.011）。
结论
用于前列腺 NVB 追踪的放大 EPI DTI 采集可改善图像和束纤维质量的定量和定性指标，允许在 3T 时不使用直肠内线圈进行 NVB 追踪。
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