基于美国放射学院(ACR)标准的医用磁共振成像系统质量控制检测及处置界限建立

Quality Control Test of MRI System and Action Limits Setting Based on American College of Radiology(ACR) Standards

目的基于美国放射学院(American College of Radiology,ACR)标准对Siemens Trio 3.0 T磁共振成像系统的中心频率、空间分辨率、低对比度分辨率、信噪比、图像均匀性、几何精度和层厚进行质量控制检测,研究基于ACR标准的MRI系统质控检测的测算方法、检测结果,并建立处置界限。方法使用ACR磁共振性能检测专用模体,根据ACR标准要求采用自旋回波序列对模体进行扫描,在扫描得到的图像上进行质控检测参数测算,得出检测结果,建立起质控检测指标的处置界限。结果 Siemens Trio 3.0 T磁共振成像系统中心频率均值为(123216843.8±16.71)Hz,处置界限为周变化≤246 Hz;空间分辨率检测结果均为1.0 mm(左右),1.0 mm(顶底),处置界限应≤1.0 mm;低对比度分辨率可识别轮辐个数为40个,处置界限为40个;图像信噪比均值为(520.214±56.20),处置界限为周变化±56.20以内;图像均匀性处置界限≥82%;几何精度(X方向、Y方向、Z方向)处置界限为(D真±2)mm;层厚处置界限为(5.0±0.7)mm以内。结论根据ACR标准要求,本系统质量控制检测结果均在处置界限范围内,设备运行良好。

Objective To test the central frequency, spatial resolution, low contrast resolution, signal-to-noise ratio （SNR）, image uniformity, geometric accuracy and thickness of Siemens Trio 3.0 T MRI system based on ACR standards. Methods According to the ACR standard, the ACR MRI phantom was scanned using spin echo sequence. The quality control testing parameters were calculated in the scanned image, and then we got the test results and action limits setting. Results The mean central frequency was （123216843.8±16.71） Hz, and action limits was≤246 Hz. Spatial resolution of both left-right and top-bottom were 1.0 mm respectively, and action limits was ≤1.0 mm. Low contrast resolution total number of spokes on all slices was 40, while action limits was 40. The signal-to-noise ratio was （520.214±56.20）, and action limits was allowable within ±56.20. Image uniformity action limits was ≥82%. Geometric accuracy （X-direction, Y-direction and Z-direction） action limits was within ±2 mm of the true values, and the layer thickness should be within （5.0±0.7） mm. Conclusion The quality control testing parameters based on the ACR standard are all in action limits.