Kinematic MRI of knee in wide bore 3T MR system

초록

Target audience: Musculoskeletal radiologist Introduction Menisci were proved to be mobile, allowing movement in either an anterior–posterior direction or in a lateral–medial direction during flexion and extension (1). The protrusion of any part of the meniscus beyond the tibial plateau has been area of interest but kinematic MRI in different knee positions was only available in additional open MR system equipment which has low spatial resolution related to low magnetic field and much motion artifact. The recent development of wide bore 3T MRI raised the expectation of possibility of kinematic MRI with good spatial resolution and an isotropic high-spatial-resolution 3D data without additional MR equipment. The purpose of our study was to evaluate feasibility of kinematic MR imaging in wide bore 3T MRI and to assess position related changes of the meniscus, and medial/lateral tibiofemoral joint in flexion and extension position in asymptomatic volunteers. Methods Five knees from five asymptomatic volunteers with no history of knee injury were examined with a 3T wide bore MR system (Discovery 750 W, GE healthare). Sagittal 2D fast spin echo T2 weighted sequences (TR, 4000-5000 ms; TE,70-80 ms, ETL, 14, NEX, 2, slice thickness, 3 mm; field of view (FOV), 150 mm; acquisition matrix, 416 x 288; and bandwidth, 62.5 Hz.) and 3D-FSE-Cube (TR, 1200 ms; TE, 44.1-49.7 ms ETL, 60; slice thickness, 0.6 mm; field of view (FOV), 150 mm; acquisition matrix, 188 x188; and bandwidth, 62.5 Hz. scan time: 8 minutes) were obtained with extension of knee in supine position (extension), and with flexion of knee in lateral decubitus position (flexion) using medium sized phased array coil (Figure 1). The position of menisci regard to the vertical tibial reference lines, medial and lateral joint space, and meniscal flounce were evaluated in extension and flexion position. Statistical analysis was used Wilcoxon Signed Ranks Test. Results and Discussion All images