关键词: 伪影, MRI序列, 快速自旋回波, 自旋回波

Abstract: Objective This study aimed to observe and evaluate six 3.0 T sequences of metallic artifacts produced by metal dental crowns. Methods Dental crowns fabricated with four different materials (Co-Gr, Ni-Gr, Ti alloy and pure Ti) were evaluated. A mature crossbreed dog was used as the experimental animal, and crowns were fabricated for its upper right second premolar. Each crown was examined through head MRI (3.0 T) with six sequences, namely, T₁weighted-imaging of spin echo (T₁W/SE), T₂ weighted-imaging of inversion recovery (T₂W/IR), T₂ star gradient echo (T₂*/GRE), T₂ weighted-imaging of fast spin echo (T₂W/FSE), T₁weighted-imaging of fluid attenuate inversion recovery (T₁W/FLAIR), and T₂weighted-imaging of propeller (T₂W/PROP). The largest area and layers of artifacts were assessed and compared. Results The artifact in the T₂*/GRE sequence was significantly wider than those in the other sequences (P<0.01), whose artifact extent was not significantly different (P>0.05). Conclusion T₂*/GRE exhibit the strongest influence on the artifact, whereas the five other sequences contribute equally to artifact generation.

Key words: artifacts, MRI sequences, fast spin echo, spin echo