最大斜率法和去卷积法对胰腺CT灌注参数影响的对比研究

Comparison of maximum slope and deconvolution algorithms on perfusion parameters in pancreatic CT perfusion

目的:探讨胰腺CT灌注成像中最大斜率法(MS)和去卷积算法(DC)对灌注参数的影响差异。方法 :回顾性分析因临床需要进行了胰腺CTP检查,且图像质量较好的57例患者资料,患者均行320排容积CT胰腺CTP检查,并分别采用MS法和DC法处理数据。由2名放射科医师采用双盲法对30例正常胰腺头体尾共90个ROI及27例急性间质水肿性胰腺炎共81个ROI进行分析,测得灌注参数值,包括血流量(BF),血容量(BV)。采用组内相关系数(ICC)比较不同医师测量结果间一致性,采用配对t检验比较两种算法间所得各项CTP参数值的差异;采用Pearson线性相关分析评价各项CTP参数值间的相关性;采用Bland-Altman分析评价两种算法所得各项CTP参数值间的一致性。结果:2名医师的测量结果一致性较好(ICC≥0.9)。正常及病变组胰腺的BF、BV值MS法均高DC法,差异有统计学意义(P均<0.05);同一算法正常及病变组胰腺头体尾不同区域的BF、BV无统计学差异(P>0.05)。两种算法测得的BF、BV结果间均具有良好的相关性(r值均>0.9,P<0.01),但不一致。结论 :MS和DC两种算法所测得正常及病变组胰腺的BF、BV具有较好的相关性,但一致性不佳,故数据不可交互使用。

Objective： To investigate the effects of maximum slope （MS） and deconvolution （DC） approach on perfusion pa- rameters in pancreatic CT perfusion. Methods： The data of 57 patients who underwent pancreatic CT perfusion examination by 320-slice CT with good image quality were retrospectively analyzed using MS and DC algorithms respectively. Images were il- lustrated by two certified radiologists using double blind method and perfusion parameters including blood flow （BF）, blood vol- ume（BV） were obtained in 30 cases of normal pancreatic heads, bodies and tails （including 90 ROIs） and 27 cases of acute pancreatitis with interstitial edema（including 81 ROIs）. The intraclass correlation coefficient（ICC） was used to assess the repro- ducibility between two radiologists and paired t test was used to evaluate the differences of CT perfusion parameters between the two algorithms. Pearson linear correlation analysis and Bland-Ahman analysis were used to estimate the correlation and consistency of the CT perfusion parameters between the two algorithms. Results： There was good agreement（ICC≥0.9） between the two radiologists. There were no significant differences in BF or BV in different regions of the pancreas in either normal pancreas or acute pancreatitis through the same algorithm （P〉0.05）. In comparison with corresponding values obtained from DC algorithm, the values of pancreatic BV and BF obtained from MS algorithm were higher （P〈0.05） in both normal pancreatic body and acute pancreatitis. In addition, there was a significant positive but inconsistent correlation between BF and BV val- ues of different pancreatic regions in both normal pancreas and acute pancreatitis with interstitial edema through the same al- gorithm （r〉0.9, P〈0.01）. Conclusions： Perfusion parameters obtained from MS and DC algorithms show good, but inconsistent correlation. Thus, the data cannot be used interchangeably between algorithms.