MAGiC序列应用于青年志愿者骶髂关节扫描的可行性研究

Feasibility study on application of MAGiC sequence in sacroiliac joint of young volunteers

目的探讨MR集合序列(magnetic resonance image compilation,MAGiC)用于青年志愿者骶髂关节扫描的可行性。材料与方法30名青年志愿者分别行骶髂关节MRI常规序列和MAGiC序列扫描。首先由2名研究者分别对常规序列(T1WI-FSE、T2WIFSE、STIR)和MAGiC序列(T1WI、T2WI、STIR)图像质量进行评分,采用Kappa检验评价一致性。然后测量信号噪声比(signal noise ratio,SNR)和对比噪声比(carrier to noise ratio,CNR);最后利用MAGiC T2-mapping序列测量骶髂关节面下骨髓T2值。结果60侧骶髂关节纳入本研究。常规序列和MAGiC序列图像质量评分有显著差异(P<0.05);观察者间一致性检验Kappa>0.60。MAGiC序列图像的SNR和CNR均优于常规序列(P<0.05)。MAGiC T2-mapping测得骶髂关节面下骨质的T2值(83±8)ms,且髂侧稍高于骶侧(P<0.05)。结论青年志愿者骶髂关节MAGiC序列的图像质量评分较常规序列稍低,但SNR和CNR较优且能获得多组定量参数,可用于骶髂关节MR扫描。

Objective:To explore the feasibility of applying magnetic resonance image compilation(MAGiC)sequence to MR examination of sacroiliac joint in young volunteers.Materials and Methods:All participants(14 male,16 female)underwent conventional sequences and MAGiC sequence scanning.Image quality,atifacts,the signal to noise ratio(SNR)and the carrier to noise ratio(CNR)were assessed independently by two observers(a radiologist and a radiologic technologist)on both conventional sequences(T1WI-FSE,T2WI-FSE,STIR)and MAGiC sequences(T1WI,T2WI,STIR).Kappa(K)statistic was used to evaluate the consistency of observers.T2 value of subchondral bone were measured on MAGiC T2-mapping images.Results:Thirty young volunteers were performed MR examination(60 sacroiliac joints included).The image quality scores of conventional sequences T1WI,T2WI and STIR were 5(0),5(0)and 5(0),which of MAGiC reconstruction sequences were 5(1),5(1)and 3(2),with statistically significant differences(P<0.05).The consistency check between observers showed K>0.61.The SNR of T1WI sequence and MAGiC T1WI sequence were 12.61±0.37,13.96±0.52(t=-2.63,P<0.05),the CNR of two sequences were 1.06±0.04,1.18±0.28(Z=-2.373,P<0.05).The SNR of T2WI sequence and MAGiC T2WI sequence were 12.84±0.48,112.63±0.45(t=0.447,P>0.05),the CNR of two sequences were 1.57±0.05,1.54(0.03)(Z=-1.486,P>0.05).The SNR of STIR sequence and MAGiC STIR sequence were 8.36(3.77),5.73±0.52(Z=-3.19,P<0.05),the CNR of two sequences were-1.9(10.29),0.95±0.08(Z=-1.46,P>0.05).There was no statistical difference of artifact score between conventional sequences and MAGiC sequences[conventional sequences:50 cases(83.3%,grade 1),8 cases(13.3%,grade 2),2 cases(3.3%,grade 3).MAGiC sequences:34 cases(56.6%,grade 1),18 cases(30%,grade 2),8 cases(13.3%,grade 3),Z=-4.443,P<0.001].The mean T2 value was(83±8)ms,and the iliac side was slightly higher than sacral side(P<0.05).Conclusions:Though the subjective image quality score of MAGiC sequence images are slightly lower than conventional sequences images,but with higher SNR and CNR,shorter scanning time,more quantitative parameters,MAGiC sequence can be used for MR examination of sacroiliac joint in young volunteers.