Magnetic resonance delineation of the anterior cruciate ligament of the knee: Flexed knee position within a surface coil

The purpose of this study was to evaluate the effect of the knee position at three different flexion angles in magnetic resonance (MR) delineation of the anterior cruciate ligament (ACL) in the knee and to determine the optimal knee position. Thirteen knees of normal volunteers were examined at 15°, 30°, and 45° of flexion with a surface coil, and three sets of obtained oblique sagittal MR images were evaluated by four observers. MR images at 30° of knee flexion most clearly delineate compared with those at 15° and 45° of knee flexion. We recommended examining the knee in 30° of flexion.