心电门控模式下能谱扫描和传统扫描CT值与碘对比剂浓度相关性的比较

Comparison of the correlation between CT attenuation value and iodine concentration of contrast medium using spectral CT under ECG-gated mode and traditional CT

目的:评价在心电门控模式下能谱扫描和传统扫描CT值与碘对比剂浓度的关系。方法:使用能谱CT对不同浓度的碘对比剂(0~40mg/mL)分别在心脏能谱模式、心脏非能谱模式、胸部能谱模式、胸部非能谱模式进行扫描,对各模式下各能级图像(40~140KeV,间隔10KeV)及传统非能谱扫描图像(80、100、120、140kV)CT值进行测量,分析CT值与碘对比剂浓度的关系。结果:四种扫描模式下,CT值和碘对比剂浓度均呈线性关系。对能谱模式、非能谱模式的R^2值进行配对秩和检验(P=0.112>0.05),二者之间没有明显的统计学差异。四种不同扫描模式的R^2值进行非参数秩和检验(χ2=3.6,P=0.308>0.05),说明四种不同扫描模式的R^2值没有明显的统计学差异。但能谱模式的R^2均值(R^2=0.99953)高于非能谱模式(R^2=0.99940),心脏能谱模式(R^2=0.99972)略高于胸部能谱模式(R^2=0.99934)。结论:能谱扫描模式下心脏模式和非心脏模式的CT值和碘对比剂浓度均呈高度线性相关,可以用于CT值的定量测量。

Objective：To evaluate the relationship between the CT value and iodine concentration of contrast medium using spectral CT under ECG-gated mode and traditional CT. Methods：Contrast medium with different Iodine concentration （0-40mg/mL） were scanned using spectral CT under the following 4 modes： ECG-gated mode, non-ECG-gated mode, Spectral energy mode of chest and non-Spectral energy mode of chest. 40- 140keV,interval 10keV were used in spectral CT and 80,100,120 and 140kV was used in traditional CT separately. The CT values were measured, the relationship of the CT values and the Iodine concentration of the contrast medium were analyzed. Results： Linear correlation were found between CT value and iodine concentration for all four modes. No significant statistic difference of R2 was found between spectral and non-spectral modes （P= 0. 112-0.05）. For the four different scanning modes, there were no significant statistic differences （x2 = 3.6, P= 0. 308- 0.05）. Yet, for the average value of R2 of spectral mode （R2= 0. 99953）, which was higher than that of non-spectral mode （R2=0. 99940）, and spectral mode with ECG-gating mode （R2= 0. 99972） was slightly higher than that of traditional with ECG-gating mode （R2= 0. 99934）. Conclusion： The CT values of spectral mode no matter under ECG-gating or non ECG-gating were all showed high linear correlation with the Iodine concentration in contrast medium, which could be used in the quantitative measurement of CT attenuation value.