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目的探讨在正常肝脏和结直肠癌肝转移瘤中,灌注分数f、准扩散系数D*和扩散系数D测量的可重复性。材料与方法 14例已诊断为结直肠癌肝转移的病人行两次平面回波呼吸门控DW-MRI检查,每次行8个b值的扫描(0~900s/mm2),两次检查间隔1h。在不同b值的影像上圈画转移瘤和正常肝组织作为感兴趣区。进行高ADC值(b值≥100s/mm2)和非相干性运动(IVIM)参数f、D*、D最小平方的数据拟合。中位ADC值、高ADC值、f、D*、D值短期测量的可重复性分析采用Bland-Altman分析法。结果结直肠癌肝转移的ADC、高ADC和D值测量的可重复性(-21%~+25%)比肝实质的测量(-6%~+8%)差。转移瘤的灌注敏感性参数f(-75%~+241%)与D*(-89%~+2120%)测量的可重复性较差。在正常肝脏f值(-24%~+25%)与D*(-31%~+59%)测量的可重复性稍差。结论对广泛来源于IVIM最小平方的f和D*测量的可重复性较差。对IVIM灌注敏感性参数测量的可重复性的提高有待于进一步研究。要点①扩散加权MR成像定量参数越来越多地应用于临床治疗决策中。②IVIM的灌注敏感性参数的测量可重复性较差。③对转移瘤的IVIM参数测量的可重复性与正常肝脏的测量比较更差。④对IVIM参数测量的可重复性的提高需要进一步研究。
Objective To investigate the repeatability of perfusion fraction f, quasi-diffusion coefficient D * and diffusion coefficient D in liver metastases of normal liver and colorectal cancer. Materials and Methods Fourteen patients who had been diagnosed with colorectal liver metastasis underwent 2D planar echo-respiration gated DW-MRI. Each scan was performed on 8 b-values (0-900s / mm2) 1h. Metastatic tumors and normal liver tissue were scored as regions of interest on images of different b values. Data fitting for the least squares of high ADC values (b values> 100 s / mm2) and non-coherent motion (IVIM) parameters f, D *, D was performed. Median ADC values, high ADC values, f, D *, and D values were measured using the Bland-Altman analysis for reproducibility of short-term measurements. Results The reproducibility of ADC (-21% ~ + 25%) in ADC of liver metastasis of colorectal cancer was higher than that of liver parenchyma (-6% ~ + 8%). Metastatic tumor perfusion sensitivity parameters f (-75% ~ + 241%) and D * (-89% ~ + 2120%) measurement repeatability is poor. The repeatability of the measured f-values (-24% to + 25%) and D * (-31% to + 59%) in normal liver is slightly worse. Conclusions The repeatability of the f and D * measurements widely derived from the IVIM least squares is poor. Increased reproducibility of IVIM perfusion sensitivity parameters remains to be seen. Points ① Quantitative parameters of diffusion-weighted MR imaging are increasingly used in clinical treatment decisions. ② The IVIM perfusion sensitivity parameter measurement repeatability is poor. The repeatability of IVIM parameters of metastatic tumors was worse than that of normal liver. ④ IVIM parameters to improve the repeatability of measurement needs further study.