Hirano Masaki, Muto Yuki, Kuroda Masahiro, Fujiwara Yuta, Sasaki Tomoaki, Kuroda Kazuhiro, Kamizaki Ryo, Imajoh Satoshi, Tanabe Yoshinori, Al-Hammad Wlla E, Nakamitsu Yuki, Shimizu Yudai, Sugimoto Kohei, Oita Masataka, Sugianto Irfan, Bamgbose Babatunde O
Department of Radiological Technology, Graduate School of Health Sciences, Okayama University, Okayama 700-8558, Japan.
Department of Radiology, Osaka Red Cross Hospital, Osaka 543-8555, Japan.
Exp Ther Med. 2023 Jan 24;25(3):109. doi: 10.3892/etm.2023.11808. eCollection 2023 Mar.
Magnetic resonance imaging (MRI) is superior to computed tomography (CT) in determining changes in tissue structure, such as those observed following inflammation and infection. However, when metal implants or other metal objects are present, MRI exhibits more distortion and artifacts compared with CT, which hinders the accurate measurement of the implants. A limited number of reports have examined whether the novel MRI sequence, multiacquisition variable-resonance image combination selective (MAVRIC SL), can accurately measure metal implants without distortion. Therefore, the present study aimed to demonstrate whether MAVRIC SL could accurately measure metal implants without distortion and whether the area around the metal implants could be well delineated without artifacts. An agar phantom containing a titanium alloy lumbar implant was used for the present study and was imaged using a 3.0 T MRI machine. A total of three imaging sequences, namely MAVRIC SL, CUBE and magnetic image compilation (MAGiC), were applied and the results were compared. Distortion was evaluated by measuring the screw diameter and distance between the screws multiple times in the phase and frequency directions by two different investigators. The artifact region around the implant was examined using a quantitative method following standardization of the phantom signal values. It was revealed that MAVRIC SL was a superior sequence compared with CUBE and MAGiC, as there was significantly less distortion, a lack of bias between the two different investigators and significantly reduced artifact regions. These results suggested the possibility of utilizing MAVRIC SL for follow-up to observe metal implant insertions.
磁共振成像（MRI）在确定组织结构变化方面优于计算机断层扫描（CT），比如在炎症和感染后观察到的那些变化。然而，当存在金属植入物或其他金属物体时，与CT相比，MRI会出现更多的畸变和伪影，这会妨碍对植入物的准确测量。仅有少数报告研究了新型MRI序列——多采集可变共振图像组合选择性序列（MAVRIC SL）能否在无畸变的情况下准确测量金属植入物。因此，本研究旨在证明MAVRIC SL能否在无畸变的情况下准确测量金属植入物，以及金属植入物周围区域能否在无伪影的情况下被清晰勾勒出来。本研究使用了一个含有钛合金腰椎植入物的琼脂模型，并使用3.0 T MRI机器对其进行成像。总共应用了三种成像序列，即MAVRIC SL、容积内插三维扰相GRE序列（CUBE）和磁共振图像合成（MAGiC），并对结果进行了比较。由两名不同的研究人员在相位和频率方向上多次测量螺钉直径和螺钉之间的距离，以此评估畸变情况。在对模型信号值进行标准化之后，采用定量方法检查植入物周围的伪影区域。结果显示，与CUBE和MAGiC相比，MAVRIC SL是一种更优的序列，因为其畸变明显更少，两名不同研究人员之间不存在偏差，且伪影区域显著减小。这些结果表明利用MAVRIC SL进行随访观察金属植入物植入情况具有可能性。
