Department of Radiology, and Medical Imaging Research Center, Namazi Hospital, Namazi Square, Shiraz, Iran.
Eur J Radiol. 2012 Mar;81(3):584-90. doi: 10.1016/j.ejrad.2010.11.014. Epub 2010 Dec 13.
The aim of the present study was to evaluate the metallic artifacts in MRI of the orthopedic patients after removal of metallic implants.
From March to August 2009, 40 orthopedic patients operated for removal of orthopedic metallic implants were studied by post-operative MRI from the site of removal of implants. A grading scale of 0-3 was assigned for artifact in MR images whereby 0 was considered no artifact; and I-III were considered mild, moderate, and severe metallic artifacts, respectively. These grading records were correlated with other variables including the type, size, number, and composition of metallic devices; and the site and duration of orthopedic devices stay in the body.
Metallic susceptibly artifacts were detected in MRI of 18 of 40 cases (45%). Screws and pins in removed hardware were the most important factors for causing artifacts in MRI. The artifacts were found more frequently in the patients who had more screws and pins in the removed implants. Gender, age, site of implantation of the device, length of the hardware, composition of the metallic implants (stainless steel versus titanium), and duration of implantation of the hardware exerted no effect in producing metallic artifacts after removal of implants. Short TE sequences of MRI (such as T1 weighted) showed fewer artifacts.
Susceptibility of metallic artifacts is a frequent phenomenon in MRI of patients upon removal of metallic orthopedic implants.
本研究旨在评估骨科患者金属植入物去除后的 MRI 中的金属伪影。
2009 年 3 月至 8 月，对 40 名因去除骨科金属植入物而接受术后 MRI 检查的骨科患者进行了研究。对 MR 图像中的伪影进行了 0-3 级评分，其中 0 级为无伪影；1-3 级分别为轻度、中度和重度金属伪影。这些分级记录与其他变量相关，包括金属装置的类型、大小、数量和组成；以及骨科装置在体内的位置和停留时间。
在 40 例病例中的 18 例（45%）中检测到 MRI 中的金属敏感性伪影。去除的硬件中的螺钉和销钉是引起 MRI 伪影的最重要因素。在去除植入物中有更多螺钉和销钉的患者中，发现伪影的频率更高。性别、年龄、装置植入部位、硬件长度、金属植入物的组成（不锈钢与钛）以及硬件植入时间对去除植入物后产生金属伪影没有影响。MRI 的短 TE 序列（如 T1 加权）显示的伪影较少。
在去除金属骨科植入物后的 MRI 中，金属伪影的易感性是一种常见现象。
