健康实验兔肾血流灌注超声造影定量分析方法学研究

Quantitative evaluation of contrast-enhanced ultrasound in healthy rabbits

目的比较在选择不同感兴趣区域(ROI)的条件下,健康实验兔肾超声造影增强图像血流灌注参数定量分析结果有无差异。探讨超声造影定量分析技术在评价肾血流灌注中的影响因素。方法采用低机械指数下实时谐频超声造影观察28例健康实验兔肾,用QLAB定量分析软件(Philips),选择6种不同的ROI,分别进行肾血流灌注定量分析,测量肾皮质的超声造影灌注参数值,包括上升支斜率(A)、下降支斜率(α)、曲线下面积(AUC)、曲线达峰强度绝对值(DPI)、达峰时间(TTP),并比较同一定量参数在设置不同形状、位置的ROI分析结果中有无差异。结果对于不同形状的ROI而言,肾血流灌注曲线TTP的差异有统计学意义(P<0.05),而A、α、DPI及AUC的差异无统计学意义。同样形状、大小的ROI置于皮质内与髓质内,其各项定量参数都具有显著性差异(P<0.05),而不同部位、深度的肾皮质超声造影定量参数的差异主要体现在DPI及TTP(P<0.05)。结论超声造影定量分析技术操作简便,准确性高,适合临床运用。超声造影定量分析结果受ROI的形状、位置及大小的影响,在实际应用中需加以考虑。

Objective To evaluate the quantitative value of contrast-enhanced ultrasound in kidneys of healthy rabbits. To compare different quantitative results with different settings of region of interest （ROI）. Methods The contrast-enhanced ultrasound examinations were performed on both kidneys in 28 healthy rabbits. The slope rate of ascending curve （ A）, the slope rate of descending curve （ α）, area under curve （ AUC）, derived peak intensity （ DPI ）, and time to peak （TTP） were measured in kidneys of rabbits using QLAB software package （Philips） and were statistically analyzed. Quantitative results of different ROIs were compared. Results The changes in A,α, AUC, DPI were not statistically significant between different shapes of ROI, respectively （ P 〉 0.05 ）. The various changes of quantitative indexes were observed between ROIs in cortex and kidney medullar of rabbits. As to the different settings of ROIs in renal cortex, significant changes in DPI and TTP were found. Conclusion Contrast-enhanced ultrasound can provide accurate and convenient means of displaying the hemodynamic blood perfusion status of kidneys in rabbits. The shape, position and size of ROI would play an important role in the quantitative results.