MRI Unit, Royal Marsden NHS Foundation Trust, London, United Kingdom.
Division of Radiotherapy and Imaging, The Institute of Cancer Research, London, United Kingdom.
Phys Med Biol. 2024 Jun 17;69(12). doi: 10.1088/1361-6560/ad4195.
Image quality in whole-body MRI (WB-MRI) may be degraded by faulty radiofrequency (RF) coil elements or mispositioning of the coil arrays. Phantom-based quality control (QC) is used to identify broken RF coil elements but the frequency of these acquisitions is limited by scanner and staff availability. This work aimed to develop a scan-specific QC acquisition and processing pipeline to detect broken RF coil elements, which is sufficiently rapid to be added to the clinical WB-MRI protocol. The purpose of this is to improve the quality of WB-MRI by reducing the number of patient examinations conducted with suboptimal equipment.A rapid acquisition (14 s additional acquisition time per imaging station) was developed that identifies broken RF coil elements by acquiring images from each individual coil element and using the integral body coil. This acquisition was added to one centre's clinical WB-MRI protocol for one year (892 examinations) to evaluate the effect of this scan-specific QC. To demonstrate applicability in multi-centre imaging trials, the technique was also implemented on scanners from three manufacturers.. Over the course of the study RF coil elements were flagged as potentially broken on five occasions, with the faults confirmed in four of those cases. The method had a precision of 80% and a recall of 100% for detecting faulty RF coil elements. The coil array positioning measurements were consistent across scanners and have been used to define the expected variation in signal.. The technique demonstrated here can identify faulty RF coil elements and positioning errors and is a practical addition to the clinical WB-MRI protocol. This approach was fully implemented on systems from two manufacturers and partially implemented on a third. It has potential to reduce the number of clinical examinations conducted with suboptimal hardware and improve image quality across multi-centre studies.
全身磁共振成像(WB-MRI)的图像质量可能会因射频(RF)线圈元件故障或线圈阵列的错位而降低。基于体模的质量控制(QC)用于识别损坏的 RF 线圈元件,但这些采集的频率受到扫描仪和人员可用性的限制。这项工作旨在开发一种特定于扫描的 QC 采集和处理管道,以检测损坏的 RF 线圈元件,其速度足够快,可以添加到临床 WB-MRI 协议中。其目的是通过减少使用次优设备进行的患者检查次数来提高 WB-MRI 的质量。
开发了一种快速采集(每个成像站额外采集 14 秒)方法,该方法通过从每个单独的线圈元件获取图像并使用整体体线圈来识别损坏的 RF 线圈元件。该采集方法在一个中心的临床 WB-MRI 协议中添加了一年(892 次检查),以评估这种特定于扫描的 QC 的效果。为了证明在多中心成像试验中的适用性,该技术还在来自三个制造商的扫描仪上实施。
在研究过程中,有五次标记 RF 线圈元件可能出现故障,其中四次得到了确认。该方法检测有故障的 RF 线圈元件的精度为 80%,召回率为 100%。线圈阵列定位测量在扫描仪之间是一致的,并已用于定义信号的预期变化。
这里展示的技术可以识别有故障的 RF 线圈元件和定位错误,并且是临床 WB-MRI 协议的实用补充。该方法已在两个制造商的系统上全面实施,并在第三个制造商的系统上部分实施。它有可能减少使用次优硬件进行的临床检查次数,并提高多中心研究中的图像质量。