PITFALLS AND ARTIFACTS ENCOUNTERED IN CLINICAL MR-IMAGING OF THE SPINE

Magnetic resonance (MR) imaging of the spine has become widely accepte d as a valuable diagnostic tool. However, there are a number of artifa cts and pitfalls associated with spinal MR imaging. Chemical shift art ifacts may be induced by bone marrow, epidural fat, or intradural fat. Motion artifacts arise from several sources, which include respiratio n, flow Of fluids, and swallowing. Artifacts due to a nonuniform magne tic field,,, particularly noticeable within trabecular bone or at bone -soft tissue interfaces but may also be caused by incomplete fat satur ation or the presence of metal near the spine. Protocol errors may cau se artifacts such as saturation, phase wraparound, truncation, radio-f requency interference, shading, and partial volume averaging. Use of f at saturation, use of motion and flow compensation, and careful screen ing of patients for metal in clothing can help reduce the occurrence o f artifacts. In addition, use of an optimal imaging technique is essen tial and should include use of the proper surface coil, field of view, and pulse sequence.