Custom bed designed for dual-modality preclinical imaging of the knee. Non-ferromagnetic plastic was used to position the rat with its knees extended. Upon completion of an MRI scan, the surface coil was retracted and a tissue calibration phantom (not shown) was placed along the joint line. The animal remained splinted to the bed for both MRI and micro-CT imaging sessions, which inhibited knee flexion and improved image registration. micro-CT, micro computed tomography; MRI, magnetic resonance imaging.