The protons in collagen‐rich musculoskeletal (MSK) tissues such as the Achilles tendon are subject to strong dipolar interactions which are modulated by the term (3cos²θ‐1) where θ is the angle between the fiber orientation and the static magnetic field B₀. The purpose of this study was to investigate the magic angle effect in three‐dimensional ultrashort echo time Cones Adiabatic T_1ρ (3D UTE Cones‐AdiabT_1ρ) imaging of the Achilles tendon using a clinical 3 T scanner. The magic angle effect was investigated by Cones‐AdiabT_1ρ imaging of five cadaveric human Achilles tendon samples at five angular orientations ranging from 0° to 90° relative to the B₀ field. Conventional Cones continuous wave T_1ρ (Cones‐CW‐T_1ρ) and Cones T₂* (Cones‐T₂*) sequences were also applied for comparison. On average, Cones‐AdiabT_1ρ increased 3.6‐fold from 13.6 ± 1.5 ms at 0° to 48.4 ± 5.4 ms at 55°, Cones‐CW‐T_1ρ increased 6.1‐fold from 7.0 ± 1.1 ms at 0° to 42.6 ± 5.2 ms at 55°, and Cones‐T2* increased 12.3‐fold from 2.9 ± 0.5 ms at 0° to 35.8 ± 6.4 ms at 55°. Although Cones‐AdiabT_1ρ is still subject to significant angular dependence, it shows a much‐reduced magic angle effect compared to Cones‐CW‐T_1ρ and Cones‐T₂*, and may be used as a novel and potentially more effective approach for quantitative evaluation of the Achilles tendon and other MSK tissues.

中文翻译：

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魔角对使用 3D 超短回波时间锥体轨迹的跟腱绝热 T1ρ 成像的影响。

富含胶原蛋白的肌肉骨骼 (MSK) 组织（如跟腱）中的质子受到强偶极相互作用的影响，该相互作用由项 (3cos ² θ-1)调制，其中 θ 是纤维取向和静磁场 B 之间的角度₀ . 本研究的目的是使用临床 3 T 扫描仪研究跟腱三维超短回波时间锥体绝热 T _1ρ (3D UTE Con​​es-AdiabT _1ρ ) 成像中的魔角效应。通过 Cones-AdiabT _1ρ成像研究了五个尸体人类跟腱样本在相对于 B _{0 的}0° 到 90° 的五个角度方向上的魔角效应场地。还应用了传统的 Cones 连续波 T _1ρ (Cones-CW-T _1ρ ) 和 Cones T ₂ * (Cones-T ₂ *) 序列进行比较。平均而言，Cones-AdiabT _1ρ增加了 3.6 倍，从 0° 时的 13.6 ± 1.5 ms 增加到 55° 时的 48.4 ± 5.4 ms，Cones-CW-T _1ρ增加了 6.1 倍，从 0° 时的 7.0 ± 1.1 ms 增加到 42.6 ± 42.6 ± ms at 55°，Cones-T2* 从 0° 时的 2.9 ± 0.5 ms 增加到 55° 时的 35.8 ± 6.4 ms，增加了 12.3 倍。尽管 Cones-AdiabT _1ρ仍然受到显着的角度依赖性，但与 Cones-CW-T _1ρ和 Cones-T ₂相比，它显示出大大减少的魔角效应*，并可用作定量评估跟腱和其他 MSK 组织的一种新颖且可能更有效的方法。