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, T₁ weighted-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), T₁ weighted-imaging of fluid attenuate inversion recovery (T₂W/FLAIR), and T₂ weighted-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.
目的: 对比3.0 T磁共振检查常用的6种序列所产生金属伪影的程度。
方法: 制作4种实验铸造冠（钴铬合金、镍铬合金、低钛合金、纯钛），给实验犬依次佩戴4种实验铸造冠，进行3.0 T磁共振自旋回波T1加权像（T1W/SE）、反转恢复T2加权像（T2W/IR）、T2*梯度回波（T2*/GRE）、快速自旋回波T2加权像（T2W/FSE）、液体衰减反转恢复T1加权像（T1W/FLAIR）、螺旋桨技术T2加权像（T2W/PROP）6种序列的头部扫描，测量6种扫描序列扫描4种铸造冠时所产生的伪影最大面积和伪影涉及图像的层数，对测量结果进行对比。
结果: 从扫描所得的图像及测量数据来看，无论扫描哪种金属，T2*/GRE序列所产生的伪影最大面积和涉及的层数均明显大于其他序列（P<0.01），其他5种序列间差异均无统计学意义（P>0.05）。
结论: T2*/GRE序列产生金属伪影程度最大，其余5种序列所产生的金属伪影程度相当。