To evaluate the typical appearance and the influence in the image interpretation of the metallic artifact which is known as one of the patient-related field artifacts, we analysed the magnetic resonance (MR) images of 40 patients (the total
number
of
metallic materials were 45) acquired at MR 1.5T unit. All patients were screened for the presence of metal. The metallic implants were surgical wires and clips, orthopedic devices, and the other miscellaneous materials. The artifacts produced by
metallic objects can be seen on MRI as the focal loss of signal and/or the local distortion of the image. Regardless of their ferromagnetic properties, metallic implants created regional artifacts in their images. Ferromagnetic materials, such as
a
lead
fragment, showed severe artifacts and nonferromagnetic metals showed mild to moderate artifacts. The conspicuity of artifact was related tot he composition, mass, shape, orientation, and the location of the metallic objects in the body. Under
high
magnetic field strength, there were no significant differences between the various pulse sequences. Artifacts are particularly prominent on gradient-echo images.
Our findings indicate that MR imaging of patients with standard nonferromagnetic metallic materials can be successfully performed and usefully interpretated.
|