Karantanas A H, Zibis A H, Papanikolaou N
CT-MRI Department, Larissa General Hospital, 1 Tsakalof Street, Larissa 412 21, Greece.
Skeletal Radiol. 2001 Feb;30(2):67-71. doi: 10.1007/s002560000307.
To assess the frequency of increased signal intensity in the patellar tendon using three-dimensional T1-weighted MRI pulse sequences.
Sixty patients were examined with a 1.0 T scanner (15 mT/m gradient strength) using a quadrature coil. Three pulse sequences were applied in the sagittal plane: PD turbo spin echo (PD-TSE), 3D T1-weighted gradient echo with fat suppression (3D-T1-FFE-FS) and 3D T1-weighted echo planar imaging with fat suppression (3D-T1-EPI-FS). The high signal intensity areas were measured in their maximum length. The angle of the patellar tendon relative to the main field position was measured in the same slice. In eight patients with anterior knee pain, and in 11 with no anterior knee pain, a fourth T2-weighted TSE pulse sequence (T2-TSE) was obtained to rule out patellar tendinitis.
The correlation of the high signal intensity areas with the relative position of the tendon was found to be significant with the 3D sequences (P = 0.03 for 3D-T1-FFE-FS and P = 0.003 for 3D-T1-EPI-FS). The length of the high signal intensity area in the tendon was 5.4 mm with 3D-T1-FFE-FS, 4.9 mm with 3D-T1-EPI-FS and 3.1 mm with PD-TSE images. No patellar tendinitis was demonstrated on the T2-TSE images.
The magic angle effect is commonly observed in the 3D based T1-weighted pulse sequences with fat suppression. The presence of the above sign must be recognized by radiologists, so that misdiagnosis of patellar tendinitis is avoided.
使用三维T1加权MRI脉冲序列评估髌腱信号强度增加的频率。
60例患者使用1.0T扫描仪（梯度强度15mT/m）及正交线圈进行检查。在矢状面应用三个脉冲序列：质子密度加权快速自旋回波（PD-TSE）、三维脂肪抑制T1加权梯度回波（3D-T1-FFE-FS）和三维脂肪抑制T1加权回波平面成像（3D-T1-EPI-FS）。测量高信号强度区域的最大长度。在同一层面测量髌腱相对于主磁场位置的角度。对8例有膝前疼痛的患者和11例无膝前疼痛的患者，获取第四个T2加权快速自旋回波脉冲序列（T2-TSE）以排除髌腱炎。
发现三维序列中高信号强度区域与肌腱相对位置的相关性具有统计学意义（3D-T1-FFE-FS的P = 0.03，3D-T1-EPI-FS的P = 0.003）。3D-T1-FFE-FS图像上肌腱高信号强度区域的长度为5.4mm，3D-T1-EPI-FS图像上为4.9mm，PD-TSE图像上为3.1mm。T2-TSE图像上未显示髌腱炎。
在基于三维脂肪抑制的T1加权脉冲序列中常见魔角效应。放射科医生必须认识到上述征象的存在，以避免髌腱炎的误诊。
