MRI disturbances caused by dental materials

Area of Science:

• Radiology
• Biomaterials Science
• Medical Imaging

Background:

• Dental materials are frequent sources of artifacts in brain Magnetic Resonance Imaging (MRI) studies.
• Understanding the impact of these materials is crucial for accurate diagnostic imaging.

Purpose of the Study:

• To quantify image disturbances from dental materials during MRI.
• To assess the risk of ferromagnetic dental material dislocation in magnetic fields.
• To identify optimal MR sequences for minimizing artifacts caused by dental materials.

Main Methods:

• Examined 35 metal-containing dental material samples (restorations, root-canal instruments) using a 1.5 T MR system.
• Created alloy cubes and balls for artifact analysis.
• Evaluated artifact characteristics and severity, including signal void zones and hyperintensive rims.
• Assessed sample dislocation in a gelatin medium within the magnetic field.
• Compared artifact intensity across different MR sequences (e.g., Spin Echo, Fast Spin Echo T2, Proton Density).

Main Results:

• No dislocation of dental material samples was observed in the 1.5 T magnetic field.
• All tested materials produced artifacts, typically a signal void zone with a hyperintensive rim.
• Artifact size and extent, including distant effects, were influenced by material shape.
• Silver-palladium (Ag-Pd) alloys, dental gold, and amalgam exhibited the least image distortion.
• Fast Spin Echo T2 and Proton Density sequences generated the least pronounced artifacts compared to routine Spin Echo sequences.

Conclusions:

• Dental materials cause MRI artifacts but do not present a dislocation hazard at 1.5 T.
• The choice of dental alloy (Ag-Pd, gold, amalgam) and MR sequence (FSE T2, PD) can significantly reduce image artifacts.
• Awareness of these factors aids in improving MRI quality in patients with dental work.