Radiology
MRI uses strong magnetic fields to align atomic nuclei (usually hydrogen protons) within body tissues, then uses a radio signal to disturb the axis of rotation of these nuclei and observes the radio frequency signal generated as the nuclei return to their baseline states. The radio signals are collected by small antennae, called coils, placed near the area of interest. An advantage of MRI is its ability to produce images in axial, coronal, sagittal and multiple oblique planes with equal ease. MRI scans give the best soft tissue contrast of all the imaging modalities. With advances in scanning speed and spatial resolution, and improvements in computer 3D algorithms and hardware, MRI has become an important tool in musculoskeletal radiology and neuroradiology.
Lameness (equine)
The bone scan offers several advantages over traditional radiographs. In some cases, it may be more sensitive due to the fact that some lesions are only apparent on radiographs after they have become chronic. The bone scan allows imaging of the pelvis, vertebral column, and upper limbs, which are areas that are usually poorly imaged by radiographs on the adult horse, due to their size. It also allows some evaluation of soft tissue, which is generally not imaged well by radiographs.