Shellock F G, Stone K R, Crues J V
Future Diagnostics, Inc., Los Angeles, CA, USA.
Med Sci Sports Exerc. 1999 Jun;31(6):788-91. doi: 10.1097/00005768-199906000-00005.
Kinematic magnetic resonance imaging (MRI) of the patellofemoral joint provides diagnostic information pertaining to patellar alignment and tracking during the earliest increments of joint flexion, when abnormalities that affect this joint are the most apparent. Recently, a low-field strength (0.2 Tesla) dedicated extremity MR system has been designed, such that only the body part that is being imaged is placed inside of the magnet bore. The purpose of this investigation was to develop a kinematic MRI technique for the patellofemoral joint using the extremity MR system and to apply this procedure in the clinical setting.
An incremental, passive positioning kinematic MRI technique was developed for the patellofemoral joint that involved obtaining three different axial section locations with the patellofemoral joint extended and then imaging these same section locations repeatedly as the patellofemoral joint was flexed in four increments up to 36 degrees of flexion. MR images were obtained using a T1-weighted spin echo sequence. Five (10 PFJ) asymptomatic volunteers and nine patients (9 PFJ) with patellofemoral joint symptoms were studied.
Volunteers had normal kinematic MRI examinations. Seven patients had lateral subluxation, and two patients had excessive lateral pressure syndrome. Two patients with lateral subluxation seen on their kinematic MRI studies had Merchant views (x-rays obtained at 45 degrees) that showed "normal" patellar alignment, illustrating the importance of imaging the patellofemoral joint at 30 degrees or less.
A kinematic MRI technique was successfully developed for the low-field extremity MR system and utilized for clinical applications. This procedure may be used to determine the presence and severity of patellar malalignment and abnormal tracking patterns.
髌股关节的运动磁共振成像（MRI）可提供有关髌股关节在关节屈曲最初阶段的髌骨对线和轨迹的诊断信息，此时影响该关节的异常最为明显。最近，设计了一种低场强（0.2特斯拉）专用四肢MR系统，使得只有正在成像的身体部位被放置在磁体孔内。本研究的目的是使用四肢MR系统开发一种用于髌股关节的运动MRI技术，并将该程序应用于临床环境。
为髌股关节开发了一种增量式、被动定位的运动MRI技术，该技术包括在髌股关节伸展时获取三个不同的轴向截面位置，然后在髌股关节以四个增量屈曲至36度屈曲时重复对这些相同的截面位置进行成像。使用T1加权自旋回波序列获得MR图像。对五名（10个髌股关节）无症状志愿者和九名有髌股关节症状的患者（9个髌股关节）进行了研究。
志愿者的运动MRI检查结果正常。七名患者出现外侧半脱位，两名患者出现外侧压力综合征。在其运动MRI研究中发现有外侧半脱位的两名患者的Merchant位片（45度时获得的X线片）显示髌骨对线“正常”，这说明了在30度或更小角度对髌股关节进行成像的重要性。
成功地为低场四肢MR系统开发了一种运动MRI技术并将其用于临床应用。该程序可用于确定髌骨排列不齐和异常轨迹模式的存在及严重程度。
