B1场校正T1 mapping测量肺癌初始T1值的可重复性及其与表观弥散系数和Ki-67表达的相关性

B1-corrected T1 mapping for measuring lung cancer native T1 value and correlations with apparent diffusion coefficient and Ki-67 expression

目的 观察B1场校正MR纵向弛豫时间成像(T1 mapping)测量肺癌初始T1值的可重复性及其与弥散加权成像(DWI)定量参数表观弥散系数(ADC)及Ki-67表达的相关性。方法 收集36例经穿刺活检或手术病理确诊的肺癌患者,包括33例单发及3例多发共39个病灶;采集胸部B1场校正T1 mapping及DWI,以免疫组织化学检测方法评估病灶组织Ki-67表达水平。由2名影像科医师(观察者A、B)独立测量病灶初始T1值和ADC,评估观察者内及观察者间测量T1值的一致性及其差异,分析肺癌初始T1值、ADC及Ki-67表达的相关性。结果 观察者A所测肺癌初始T1值为(1 436.38±222.26)ms及(1 449.58±229.98)ms,差异无统计学意义(t=-0.960,P=0.343);观察者B所测肺癌初始T1值为(1 461.30±236.44)ms,与观察者A差异无统计学意义(t=-1.532,P=0.134);观察者内[组内相关系数(ICC)=0.963,95%CI(0.928,0.980)]与观察者间[ICC=0.948,95%CI(0.901,0.973)]测量肺癌初始T1值的一致性均较好。肺癌初始T1值与Ki-67表达呈中度正相关(r=0.448,P=0.004)、与ADC呈中度负相关(r=-0.558,P<0.001),ADC与Ki-67表达呈高度负相关(r=-0.605,P<0.001)。结论 B1场校正T1 mapping测量肺癌初始T1值可重复性好;肺癌初始T1值与ADC、Ki-67表达均呈中度相关。

Objective To explore the reproducibility of B1-corrected T1 mapping for measuring lung cancer native T1 value and the correlations with quantitative parameter of apparent diffusion coefficient(ADC) of diffusion weighted imaging(DWI) and Ki-67 expression. Methods Thirty-six patients with lung cancer confirmed by biopsy or surgical pathology were collected, including 33 cases with single and 3 cases with multiple lesions, totally with 39 lesions. Chest B1-corrected T1 mapping and DWI were acquired, while immunohistochemistry of lesions were performed for Ki-67 expression level. The native T1 value and ADC of lung cancer were measured independently by 2 radiologists(observer A and observer B), respectively, the measured values were compared, the inter-and intra-observer consistency of native T1 value were evaluated, and the correlations of lung cancer native T1 value, ADC and Ki-67 expression were analyzed. Results The native T1 values of lung cancer measured twice by observer A were(1 436.38±222.26) ms and(1 449.58±229.98) ms, respectively, no significantly difference was found(t=-0.960, P=0.343). The native T1 value of lung cancer measured by observer B was(1 461.30±236.44) ms, being not significantly different compared with that of observer A(t=-1.532, P=0.134). Good intra-and interobserver consistency was found, with intra-class correlation coefficient of 0.963(95%CI [0.928, 0.980]) and 0.948(95%CI[0.901, 0.973]), respectively. Lung cancer native T1 values and Ki-67 expression were positively(r=0.448, P=0.004) but negatively moderately correlated with ADC(r=-0.558, P<0.001), while ADC were highly negatively correlated with Ki-67 expression levels(r=-0.605, P<0.001). Conclusion The reproducibility of native T1 value of lung cancer measured with B1-corrected T1 mapping was good. The native T1 value of lung cancer was moderately correlated with ADC and Ki-67 expression.