能谱CT单能量成像评价冠状动脉非钙化性斑块的临床应用

Clinical application of spectral CT single spectral imaging in the coronary artery of non calcified plaque

目的：评价宝石能谱CT单能量成像在冠状动脉管腔非钙化性狭窄的临床应用价值。方法对15例18段非钙化斑块所致的有意义狭窄（狭窄度≥50％）进行从40 keV到90 keV单光子成象，间隔5 keV，获取18段病变血管11组单能量图像，测量每个病变区并比较每例被检者每组单能量图像的噪声值（以SD值表示）、信噪比（SNR）及对比噪声比（CNR）并选取最佳信噪比及最佳对比噪声比的图像与常规140 kVp混合能量图像进行比较，采用配对分析法比较组间数据差异。结果18例11组单能量成像中，随着keV降低，噪声值逐步增高，75 keV单能量图像平均噪声最低，70 keV以下单能量图像噪声差异有统计学意义，70 keV以上单能量图像噪声差异无统计学意义，75 keV噪声最低，病变区域最高信噪比及对比噪声比集中在（65～75） keV，其中以70 keV组最高，分别为29＆#177;7及30＆#177;8，在信噪比中3组之间差异无统计学意义（P＞0.05），在对比噪声比中70 keV与75 keV组间差异无统计学意义（P＞0.05），而与邻组信噪比及对比噪声比差异有统计学意义（P＜0.05），与混合能量图像信噪比及对比噪声比差异有统计学意义（t值分别为5.37及7.07，P＜0.01）。结论能谱（65～75） keV，单能量图像对冠状动脉非钙化性斑块信噪比及对比噪声比相对较高，65 keV对类脂性斑块敏感性较高，在低剂量低幅射量检查中具有较高的临床价值。

Objective To evaluate the clinical application value of single energy stones energy spectrum CT imaging in coronary artery lumen narrow of non calcified. Methods Fifteen cases of 18 period of non calcified plaque which the stenosis was significant （≥50%） were to be for single photon imaged from 40 keV to 90 keV, by interval 5 keV, and getting 18 paragraph lesion blood vessel 11 groups of single energy of image. By measurement of each lesion area and comparing with each case of single image values （expressed in SD value）, the signal to noise ratio （SNR） and contrast to noise ratio（CNR） and selecting the best signal-to-noise ratio and the best contrast to noise ratio compared with conventional 140 kVp hybrid energy image of data differences between paired comparison group. Results In 11 single energy imaging group of 18 cases, the noise value increased with keV decreasing, the average noise value was lowest for 75 keV single energy image, There were significant differences in the single energy noise below 70 keV, more than 70 keV single noise energy difference had not significant differences, 75 keV noise was lowest, highest signal-to-noise ratio and lesion contrast SNR was concentrated in the （65-75） keV, of which 70 keV group is highest, （29 ±7 and 30±8） respectively, in the signal to noise ratio, There was no obvious difference between the three groups （P〉0.05）;There was no difference in contrast SNR 70 keV and 75 keV groups （P〉0.05）, and compared with adjacent group signal-to-noise ratio SNR has difference（P〈0.05）, compared with hybrid energy image signal-to-noise ratio signal-to-noise ratio difference is significant （t=5.37 and 7.07, P〈0.01）. Conclusion Spectrum （65-75） keV, single energy image of non calcified coronary artery plaque signal-to-noise ratio and comparative signal-to-noise ratio is relatively high, 65 keV of lipid plaque sensitivity is higher, in low doses low-rising radiometric check has higher clinical value.