Abstract：
OBJECTIVE: To evaluate the MRI artifact rendered by the typical injection of a ferromagnetic tracer now being intermittently used for intraoperative sentinel node (SN) identification at our institution, and to explore its impact on postoperative imaging and management.
METHODS: This study was Institutional Review Board-approved and granted a waiver of consent. A database search tool was used to identify MRI exams performed on patients who had previously undergone breast-conserving surgery with use of a superparamagnetic iron oxide (SPIO) SN tracer between January 1, 2015, and May 1, 2020. MRI reports, images, and relevant demographic, oncologic, and surgical history were collected. The presence or absence of SPIO residue on breast MRI, as well as its impact on image quality, were extracted from the prospective reports.
RESULTS: A total of 21 MRI exams were identified in 16 patients who had undergone breast-conservation therapy for cancer with use of SPIO SN tracer. Mean time from particle injection to baseline postoperative MRI exam was 10.8 months. All reports (21/21) noted evidence of SPIO residue. Of these, 5/21 were assessed as non-diagnostic; the remainder were assessed as limited.
CONCLUSIONS: Radiologists should be aware of the use of superparamagnetic tracers for SN identification and the impact on the quality of future MRI examinations. Alternative injection approaches are being developed and sequence parameters adjusted to minimize artifact.
METHODS: This study was Institutional Review Board-approved and granted a waiver of consent. A database search tool was used to identify MRI exams performed on patients who had previously undergone breast-conserving surgery with use of a superparamagnetic iron oxide (SPIO) SN tracer between January 1, 2015, and May 1, 2020. MRI reports, images, and relevant demographic, oncologic, and surgical history were collected. The presence or absence of SPIO residue on breast MRI, as well as its impact on image quality, were extracted from the prospective reports.
RESULTS: A total of 21 MRI exams were identified in 16 patients who had undergone breast-conservation therapy for cancer with use of SPIO SN tracer. Mean time from particle injection to baseline postoperative MRI exam was 10.8 months. All reports (21/21) noted evidence of SPIO residue. Of these, 5/21 were assessed as non-diagnostic; the remainder were assessed as limited.
CONCLUSIONS: Radiologists should be aware of the use of superparamagnetic tracers for SN identification and the impact on the quality of future MRI examinations. Alternative injection approaches are being developed and sequence parameters adjusted to minimize artifact.
摘要：
目的：为了评估由典型的铁磁示踪剂注射所产生的MRI伪影，目前在我们机构中间歇性地用于术中前哨淋巴结（SN）识别，并探讨其对术后影像学及管理的影响。
方法：本研究获得机构审查委员会批准，并同意放弃同意。数据库搜索工具用于识别在2015年1月1日至2020年5月1日之间使用超顺磁性氧化铁（SPIO）SN示踪剂进行过保乳手术的患者的MRI检查。MRI报告,images,和相关的人口统计，肿瘤学，收集手术史。乳腺MRI上是否存在SPIO残留物，以及它对图像质量的影响，是从前瞻性报告中提取的。
结果：在使用SPIOSN示踪剂进行乳腺癌保乳治疗的16例患者中，共进行了21次MRI检查。从粒子注射到基线术后MRI检查的平均时间为10.8个月。所有报告（21/21）都指出了SPIO残留的证据。其中,5/21被评估为非诊断性；其余被评估为有限。
结论：放射科医师应该意识到超顺磁示踪剂用于SN鉴定以及对未来MRI检查质量的影响。正在开发替代的注射方法，并调整序列参数以最大程度地减少伪影。
方法：本研究获得机构审查委员会批准，并同意放弃同意。数据库搜索工具用于识别在2015年1月1日至2020年5月1日之间使用超顺磁性氧化铁（SPIO）SN示踪剂进行过保乳手术的患者的MRI检查。MRI报告,images,和相关的人口统计，肿瘤学，收集手术史。乳腺MRI上是否存在SPIO残留物，以及它对图像质量的影响，是从前瞻性报告中提取的。
结果：在使用SPIOSN示踪剂进行乳腺癌保乳治疗的16例患者中，共进行了21次MRI检查。从粒子注射到基线术后MRI检查的平均时间为10.8个月。所有报告（21/21）都指出了SPIO残留的证据。其中,5/21被评估为非诊断性；其余被评估为有限。
结论：放射科医师应该意识到超顺磁示踪剂用于SN鉴定以及对未来MRI检查质量的影响。正在开发替代的注射方法，并调整序列参数以最大程度地减少伪影。
