Artifact reduction from metallic dental materials in T1-weighted spin-echo imaging at 3.0 tesla

Abstract

PURPOSE: To investigate and propose a method of artifact reduction arising from metallic dental materials by applying a slice-encoding for metal artifact correction (SEMAC) technique on T1-weighted spin-echo (SE) imaging at 3 Tesla. MATERIALS AND METHODS: The view angle tilting (VAT) technique was adapted to conventional T1-weighted spin-echo (SE) sequence to correct the in-plane distortion, and the SEMAC technique was used for correcting the remaining through-plane distortions. Fourier transform based B0 field simulations were performed to estimate the amount of field perturbation and a scout imaging method was developed which guide in selecting the number of slice-encodings needed in SEMAC sequences. Phantoms of six different dental materials with various shapes and sizes that are used in practice (amalgam; titanium implant; gold and Ni-Cr crowns; Ni-Ti and stainless steel orthodontic wires) were imaged. In vivo images of two subjects were also acquired. The amounts of artifact reduction were quantified in phantom studies. RESULTS: Compared with conventional SE imaging in phantom studies, in-plane artifacts were reduced by up to 43% in the VAT SE images and 80% in the SEMAC images. Through-plane artifacts were reduced by up to 65% in SEMAC images. In vivo SEMAC images also showed reduced artifacts. CONCLUSION: The SEMAC technique can mitigate artifact caused by metallic dental materials for T1w-SE imaging.