Artifacts in magnetic resonance imaging caused by cast metal dental crowns

Abstract

We analyzed metallic artifacts in magnetic resonance imaging (MRI) caused by 14 dental crowns made of NiCr alloy. Three sequences of MRI (FSE-3 D, FSE-2 D and SE-2 D) were taken of anterior and posteriot cast crowns combined in various arrangements. We observed the shape and the volume of the resulting metallic artifacts using multi-planer and three-dimensional reconstructions from the slice data. The metallic artifacts were divided into three signal intensities, high, intermediate and low. The shape of the crown, which was in the center of the artifact, could be detected in the area of low signal intensity. An area of high signal intensity existed only in the frequency direction of the metallic crowns in the slice data. An area of intermediate signal intensity extended widely vertically and horizontally. The high signal intensity area increased in volume as the number of crowns increased.