Evaluation of MRI artifacts caused by metallic dental implants and classification of the dental materials in use

Evaluation of MRI artifacts caused by metallic dental implants and classification of the dental materials in use

Peer-reviewed article not indexed in WoS or Scopus

Metallic objects (dental fillings, crowns, fixed bridges etc.), now found in many patients, may become a reason for the patients ineligibility for MR examination because of safety or image artifact concerns. The severity of the MRI artifacts caused by these objects depends primarily on the material, shape, position and orientation of the object, MRI method applied, and the location of the tissues of interest. The purpose of this work is to demonstrate the artifacts and describe a method of measuring the relevant material properties and the results. A method for the measurement of magnetic susceptibility based on field distortion simulation and field mapping based on MRI is described. Objects made of several materials were tested experimentally and these results were checked against simulated results. It has been found that among the more than 100 dental materials currently in use there are highly paramagnetic materials (Ni-Cr or Co-Cr based alloys), in which B0 inhomogeneity effects dominate, as well as slightly diamagnetic materials (alloys of precious metals and amalgams), which may cause artifacts due to the RF field inhomogeneity arising from induced RF currents. Spatial mapping of these effects may give indication of potential hot spots in these objects.

Metallic objects (dental fillings, crowns, fixed bridges etc.), now found in many patients, may become a reason for the patients ineligibility for MR examination because of safety or image artifact concerns. The severity of the MRI artifacts caused by these objects depends primarily on the material, shape, position and orientation of the object, MRI method applied, and the location of the tissues of interest. The purpose of this work is to demonstrate the artifacts and describe a method of measuring the relevant material properties and the results. A method for the measurement of magnetic susceptibility based on field distortion simulation and field mapping based on MRI is described. Objects made of several materials were tested experimentally and these results were checked against simulated results. It has been found that among the more than 100 dental materials currently in use there are highly paramagnetic materials (Ni-Cr or Co-Cr based alloys), in which B0 inhomogeneity effects dominate, as well as slightly diamagnetic materials (alloys of precious metals and amalgams), which may cause artifacts due to the RF field inhomogeneity arising from induced RF currents. Spatial mapping of these effects may give indication of potential hot spots in these objects.

magnetic resonance imaging, artifacts, metallic implants, dental alloys, magnetic susceptibility

STARČUK, Z.; BARTUŠEK, K.; HUBÁLKOVÁ, H.; BACHOREC, T.; STARČUKOVÁ, J.; KRUPA, P.

16.02.2006

1335-8871

Measurement Science Review

6

2

Slovak Republic

24

4