Intravoxel incoherent motion and dynamic contrast-enhanced MRI for assessing abnormalities of brucellosis spondylitis without conventional MRI changes

体素内不相干运动及动态对比增强MRI评估常规MRI无异常的布氏杆菌性脊柱炎病变

Objective To observe the value of intravoxel incoherent motion(IVIM)and dynamic contrast-enhanced MRI(DCE-MRI)for assessing abnormalities of brucellosis spondylitis(BS)without conventional MRI changes.Methods Data of 36 brucellosis patients with definite spinal lesions displayed on conventional MRI(BS 1 group),14 cases without brucellosis infection nor abnormal spinal signals on MRI(control group)and 36 brucellosis patients without definite spinal lesions on conventional MRI(BS 2 group)were retrospectively analyzed.The values of IVIM parameters,including perfusion fraction(f),pure water diffusion coefficient(D)and pseudo-diffusion coefficient(D*),also of DCE-MRI parameters,including time-intensity curve(TIC)type,volume transport constant(K trans),the rate constant(K ep)and volume fraction of extravascular extracellular space per unit tissue volume(V e)were compared among groups.Univariate and multivariate logistic regression were used to screen independent factors for discriminating BS 1 and BS 2.Receiver operating characteristic curves were drawn,and the areas under the curve(AUC)were calculated to evaluate the efficiency of the above parameters for discriminating BS 1 and BS 2.Results Among IVIM parameters,compared with control group,D*values decreased but D values increased in BS 1 group,while D*values increased in BS 2 group(all adjusted P<0.05).Compared with BS 2 group,BS 1 group had higher values of f and D and lower D*(all adjusted P<0.05).In BS 1 group,the TIC types were predominantly typeⅠ(23/36,63.89%),which were wholly or predominantly typeⅢin BS 2 group and control group,and of the former was significantly different with latter 2(both adjusted P<0.05).Compared with control group,K trans increased progressively in both BS 1 and BS 2 groups(both adjusted P<0.05).BS 1 group had lower K ep and higher V e than BS 2 and control groups(all adjusted P<0.05).Among univariate logistic regression models,the model including only f had lower capability for discriminating BS 1 and BS 2(AUC=0.759)than those including D,K trans and V e(AUC=0.951,0.833,0.894,all P<0.05).No significant different was found among multivariate logistic regression model including f and D,model including K trans and V e nor model including all above parameters(all P>0.05).Conclusion Both IVIM and DCE-MRI could be used to evaluate BS abnormality without conventional MRI changes.

目的观察体素内不相干运动(IVIM)与动态对比增强MRI(DCE-MRI)评估常规MRI无异常的布氏杆菌性脊柱炎(BS)病变的价值。方法回顾性分析常规MRI显示明确脊柱病灶的36例布鲁氏菌病患者(BS1组)、14例未见脊柱异常信号的非布鲁氏菌病患者(对照组)和36例未见明确脊柱病灶的布鲁氏菌病患者(BS2组)。比较各组灌注分数(f)、单纯水分子弥散系数(D)及灌注相关伪弥散系数(D*)等IVIM参数,以及时间-信号强度曲线(TIC)类型、容积转运常数(Ktrans)、速率常数(Kep)及单位组织体积内血管外细胞外间隙容积分数(Ve)等DCE-MRI参数;以单因素及多因素logistic回归分析筛选鉴别BS1与BS2的独立因素,绘制受试者工作特征曲线,计算曲线下面积(AUC),评估其鉴别BS1与BS2的效能。结果IVIM参数中,相比对照组,BS1组D*值降低、D值升高而BS2组D*值升高(校正P均<0.05)。相比BS2组,BS1组f及D值较高而D*值较低(校正P均<0.05)。BS1组TIC类型以Ⅰ型为主(23/36,63.89%),BS2组及对照组均为Ⅲ型或以Ⅲ型TIC为主,前者与后2组差异均有统计学意义(校正P均<0.05)。相比对照组,BS1组、BS2组Ktrans依次升高(校正P均<0.05);相比BS2组及对照组,BS1组Kep均较低而Ve均较高(校正P均<0.05)。单参数模型中,仅纳入参数f值的模型鉴别BS1与BS2的效能(AUC=0.759)低于D、Ktrans及Ve(AUC=0.951、0.833、0.894,P均<0.05);而纳入f和D值的联合参数模型、纳入Ktrans和Ve的联合参数模型及同时纳入IVIM及DCE-MRI的多参数模型的鉴别诊断效能差异均无统计学意义(P均>0.05)。结论IVIM及DCE-MRI均可用于评估常规MRI无法显示的BS病变。