Department of Radiology, Tohoku University Hospital, Sendai, Japan.
Canon Medical Systems Corporation, Tochigi, Japan.
J Magn Reson Imaging. 2021 Jun;53(6):1926-1937. doi: 10.1002/jmri.27481. Epub 2020 Dec 26.
Current contrast-enhanced magnetic resonance angiography (MRA) and non-contrast-enhanced balanced steady-state free precession (bSSFP) MRA cause susceptibility artifacts from metallic devices in assessing endovascular visceral-artery interventions. The aims of this study are to investigate and compare image quality (IQ) and susceptibility artifacts of three-dimensional (3D) ultrashort echo time (UTE) time-spatial labeling inversion pulse (Time-SLIP) with those of 3D bSSFP Time-SLIP and to assess denoising deep learning reconstruction (dDLR) for the improvement of the signal-to-noise ratio (SNR) in 3D UTE with sparse sampling in phantoms and human subjects. This is a prospective type of study. Pulsatile glycerin-water flow phantom with platinum-tungsten-alloy coil, stainless-steel, nitinol, and cobalt-alloy stents were used. Ten healthy volunteers (seven males) and three patients (two males) were included in this study. 3D UTE Time-SLIP and 3D bSSFP Time-SLIP at 3T were used. The phantom-based study compared the signal-intensity ratio of the device levels (SR ) and distal segments (SR ) to the proximal segments. The volunteer-based study measured SNR, contrast ratio (CR), and IQ. The patient study evaluated local artifacts from metallic devices. Statistical tests included paired t-tests, Wilcoxon-signed rank tests, and Kruskal-Wallis tests. In the phantom-based study, SR was small with UTE Time-SLIP, except the stainless-steel stent. SR was greater (49.1%-90.4%) on bSSFP images than UTE images (-11.1% to 9.6%). Among volunteers, dDLR in UTE images improved SNR (p < 0.05) and IQ (p < 0.05), but CR was unaffected. UTE Time-SLIP showed inferior SNR and IQ than bSSFP Time-SLIP in images with and without dDLR (p < 0.05 for each). However, among patients, UTE Time-SLIP showed reduced metal artifacts compared to bSSFP Time-SLIP. Irrespective of the lower SNR and IQ of 3D UTE Time-SLIP than those of 3D bSSFP Time-SLIP, the former appeared to better depict flow after stenting or coiling. This indicates the potential of 3D UTE Time-SLIP to provide suitable diagnostic images of target vessels. dDLR improved SNR with reducing artifacts related to radial sampling, while maintaining the contrast. LEVEL OF EVIDENCE: 2. TECHNICAL EFFICACY STAGE: 2.
当前，基于对比剂的磁共振血管造影（MRA）和非对比增强的平衡稳态自由进动（bSSFP）MRA 在评估内脏动脉血管内介入时，会因金属设备产生磁化率伪影。本研究旨在评估三维（3D）超短回波时间（UTE）时空标记反转脉冲（Time-SLIP）与 3D bSSFP Time-SLIP 的图像质量（IQ）和磁化率伪影，并评估稀疏采样的 3D UTE 中降噪深度学习重建（dDLR）对提高信噪比（SNR）的作用，在体模和人体受试者中进行研究。这是一项前瞻性研究。使用含有铂钨合金线圈、不锈钢、镍钛诺和钴合金支架的搏动甘油水流动体模。本研究纳入了 10 名健康志愿者（7 名男性）和 3 名患者（2 名男性）。在 3T 下使用 3D UTE Time-SLIP 和 3D bSSFP Time-SLIP。体模研究比较了设备水平（SR ）和远端节段（SR ）与近端节段的信号强度比。志愿者研究测量 SNR、对比比（CR）和 IQ。患者研究评估了金属设备的局部伪影。统计检验包括配对 t 检验、Wilcoxon 符号秩检验和 Kruskal-Wallis 检验。在体模研究中，除了不锈钢支架外，UTE Time-SLIP 的 SR 较小。bSSFP 图像上的 SR 大于 UTE 图像（49.1%-90.4%）（-11.1% 至 9.6%）。在志愿者中，UTE 图像的 dDLR 提高了 SNR（p<0.05）和 IQ（p<0.05），但 CR 不受影响。在有和没有 dDLR 的图像中，UTE Time-SLIP 的 SNR 和 IQ 均低于 bSSFP Time-SLIP（p<0.05）。然而，在患者中，与 bSSFP Time-SLIP 相比，UTE Time-SLIP 显示出减少的金属伪影。尽管 3D UTE Time-SLIP 的 SNR 和 IQ 低于 3D bSSFP Time-SLIP，但前者似乎更好地描绘了支架置入或线圈置入后的血流。这表明 3D UTE Time-SLIP 有可能提供目标血管的合适诊断图像。dDLR 通过减少与径向采样相关的伪影来提高 SNR，同时保持对比度。证据水平：2. 技术效果阶段：2.
