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

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.