From the Department of Diagnostic, Interventional and Pediatric Radiology (F.S., T.D.L., M.I., J.L.C., B.J.) and Department of Orthopaedic Surgery (K.A.S., M.T.), Inselspital, University Hospital Bern, University of Bern, Freiburgstrasse, 3010 Bern, Switzerland; Departments of Orthopaedic Surgery (F.S., Y.J.K., E.N.N.) and Radiology (O.A., S.D.B.), Boston Children's Hospital, Harvard Medical School, Boston, Mass; Advanced Clinical Imaging Technology, Siemens Healthcare, Lausanne, Switzerland (T.K.); Department of Radiology, Lausanne University Hospital, University of Lausanne, Lausanne, Switzerland (T.K.); LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland (T.K.); Siemens Healthcare, Zürich, Switzerland (M.K.); and Department of Orthopaedic Surgery, Cantonal Hospital, University of Fribourg, Fribourg, Switzerland (M.T.).
Radiology. 2021 Apr;299(1):150-158. doi: 10.1148/radiol.2021200085. Epub 2021 Feb 23.
Background Often used for T1 mapping of hip cartilage, three-dimensional (3D) dual-flip-angle (DFA) techniques are highly sensitive to flip angle variations related to B inhomogeneities. The authors hypothesized that 3D magnetization-prepared 2 rapid gradient-echo (MP2RAGE) MRI would help provide more accurate T1 mapping of hip cartilage at 3.0 T than would 3D DFA techniques. Purpose To compare 3D MP2RAGE MRI with 3D DFA techniques using two-dimensional (2D) inversion recovery T1 mapping as a standard of reference for hip cartilage T1 mapping in phantoms, healthy volunteers, and participants with hip pain. Materials and Methods T1 mapping at 3.0 T was performed in phantoms and in healthy volunteers using 3D MP2RAGE MRI and 3D DFA techniques with B field mapping for flip angle correction. Participants with hip pain prospectively (July 2019-January 2020) underwent indirect MR arthrography (with intravenous administration of 0.2 mmol/kg of gadoterate meglumine), including 3D MP2RAGE MRI. A 2D inversion recovery-based sequence served as a T1 reference in phantoms and in participants with hip pain. In healthy volunteers, cartilage T1 was compared between 3D MP2RAGE MRI and 3D DFA techniques. Paired tests and Bland-Altman analysis were performed. Results Eleven phantoms, 10 healthy volunteers (median age, 27 years; range, 26-30 years; five men), and 20 participants with hip pain (mean age, 34 years ± 10 [standard deviation]; 17 women) were evaluated. In phantoms, T1 bias from 2D inversion recovery was lower for 3D MP2RAGE MRI than for 3D DFA techniques (mean, 3 msec ± 11 vs 253 msec ± 85; < .001), and, unlike 3D DFA techniques, the deviation found with MP2RAGE MRI did not correlate with increasing B deviation. In healthy volunteers, regional cartilage T1 difference (109 msec ± 163; = .008) was observed only for the 3D DFA technique. In participants with hip pain, the mean T1 bias of 3D MP2RAGE MRI from 2D inversion recovery was -23 msec ± 31 ( < .001). Conclusion Compared with three-dimensional (3D) dual-flip-angle techniques, 3D magnetization-prepared 2 rapid gradient-echo MRI enabled more accurate T1 mapping of hip cartilage, was less affected by B inhomogeneities, and showed high accuracy against a T1 reference in participants with hip pain. © RSNA, 2021.
背景 常用于髋关节软骨 T1 映射的三维（3D）双翻转角（DFA）技术对与 B 不均匀性相关的翻转角变化非常敏感。作者假设 3D 磁化准备 2 快速梯度回波（MP2RAGE）MRI 将有助于比 3D DFA 技术更准确地对髋关节软骨进行 T1 映射。目的 比较 3D MP2RAGE MRI 与 3D DFA 技术，二维（2D）反转恢复 T1 映射作为髋关节软骨 T1 映射的参考标准，用于在体模、健康志愿者和髋关节疼痛参与者中进行研究。材料与方法 在体模和健康志愿者中，使用 3D MP2RAGE MRI 和 3D DFA 技术，进行 B 场映射以校正翻转角，在 3.0 T 下进行 T1 映射。髋关节疼痛的参与者前瞻性地（2019 年 7 月-2020 年 1 月）接受间接磁共振关节造影术（静脉注射 0.2 mmol/kg 钆特酸葡甲胺），包括 3D MP2RAGE MRI。在体模和髋关节疼痛的参与者中，二维反转恢复序列作为 T1 参考。在健康志愿者中，比较了 3D MP2RAGE MRI 和 3D DFA 技术之间的软骨 T1。进行了配对 t 检验和 Bland-Altman 分析。结果 11 个体模、10 名健康志愿者（中位年龄 27 岁；范围 26-30 岁；5 名男性）和 20 名髋关节疼痛的参与者（平均年龄 34 岁±10[标准差]；17 名女性）进行了评估。在体模中，与 3D DFA 技术相比，3D MP2RAGE MRI 的 2D 反转恢复 T1 偏差较低（平均 3 毫秒±11 比 253 毫秒±85；<.001），并且与 3D DFA 技术不同，MP2RAGE MRI 发现的偏差与增加的 B 偏差无关。在健康志愿者中，仅观察到 3D DFA 技术的区域性软骨 T1 差异（109 毫秒±163；=.008）。在髋关节疼痛的参与者中，3D MP2RAGE MRI 与 2D 反转恢复的平均 T1 偏差为-23 毫秒±31（<.001）。结论 与三维（3D）双翻转角技术相比，3D 磁化准备 2 快速梯度回波 MRI 能够更准确地对髋关节软骨进行 T1 映射，受 B 不均匀性的影响较小，并且在髋关节疼痛的参与者中具有较高的准确性。
