[Artifacts in magnetic resonance imaging of the head]

The results of 505 magnetic resonance (MR) imaging examinations of the head disclosed several different types of artifact. Various artifacts observed with two-dimensional Fourier transformation are described and illustrated. All images were obtained with a 0.5 Tesla superconducting MR imager. About 70% of all images contained artifacts. Phase encoding artifacts due to motion or flow were most frequently observed. Center, "zipper," truncation, radiofrequency, and ferromagnetic artifacts and contrast error on inversion recovery (IR) images were noted less frequently. Phase encoding artifacts and contrast errors on IR images totally degraded the images, and "zipper" artifacts were regional. Center artifacts resembled small infarctions, and ferromagnetic artifacts sometimes mimicked hematomas. It is important to recognize these artifacts and to devise methods to avoid their influence on the region of interest.