| Part I The Effect of Different Contrast Media concentration on Spectral CT Coronary ImagingPurpose: To study the effect of different concentration of contrast agent on the CT values in coronary lumen and the image quality and local image quality of plaques in spectral CT coronary angiography(CTCA).Methods: Fiftyone patients diagnosed or suspected with coronary heart diseases(CAD) were divided into three groups with seventeen patients in each group. All of them were undergone spectral CTCA. The contrast agent concentration was 320 mg I/100 ml for group A, 350 mg I/100 ml for group B and 370 mg I/100 ml for group C. ROIs were respectively set at three different levels of aortic root, left main(LM) coronary artery and proximal right coronary artery(RCA) and plaques. The optimal contrast-noise-ratio(CNR) analysis software was used in spectral CT workstation to select the optimal energy for displaying the coronary artery. CT value and noise(SD) and signal to noise(SNR) of each ROI and SNR and CNR of every plaque was measured under the optimal energy. The scores of image quality of main coronary segments were recorded.Results: Fifty-one patients were successfully completed inspection. In 663 coronary segments, there were 658 segments meet the diagnostic requirements(99.2%). There were 41 different compositions of plaques(20 in group A, 14 in group B, 17 in group C), among which there were 22 calcified components(7 in group A,6 in group B,9 in group C) and 19 non-calcified components(8 in group A, 6 in group B, 5 in group C). There was 9% and 14% contrast media dosage reduction between group A and group B, and between group A and group C, respectively. There was no significant difference of optimal Kev, CNR, luminal CT value, SD, SNR and the scores and the image quality of every plaque among there groups(P>0.05).Conclusion: It might not affect the enhancement in vessels and image quality with the reduced contrast concentration(320mg I/ml) in spectral CT coronary angiography(CTCA) under the optimal ke V. Part II Spectral Computer Tomography and Combined with Serum Biomarkers in Coronary Atherosclerotic Plaque Characteristics Analysis: A Preliminary StudyPurpose: To study the value of spectral CT in analyzing different coronary plaque components and their correlation with different serum levels of biomarker, and to provide a basis for the diagnosis value and differential diagnosis value of spectral CT.Materials and Methods: 107 consecutive patients diagnosed with coronary artery disease(CAD) or acute chest pain and discomfort in the anterior region of the heart(65 males and 42 females; mean age, 60±7 age) underwent coronary artery gemstone spectral imaging. Plaques were divided into 5 groups according to Multi-slice computed tomography(MSCT) criteria and the size of calcification in mixed plaques. Spectral attenuation curve(SAC), effective atomic number(EAN) and basic material decomposition: FAT and HAP technique were used to analyze the plaques. The vulnerability of plaques was evaluated by serum biomarkers including soluble OX40 ligand(s OX40L), matrix metalloproteinases(MMP-9) and lipoprotein associated phospholipase A2(Lp-PLA2). The concentrations of the serum biomarkers were detected by ELISA.Results: 159 coronary artery plaques were counted in total. 90 cases of blood samples(42 cases without coronary plaque, 48 cases with coronary plaque) were obtained. By measuring CT density, the plaques were classified as fibrosis group(group 1), soft plaque group(group 2) and pure calcification group(group 3). In addition, mixed plaques with non-spotty calcification group(group 4) and spotty calcification group(group 5) were also analyzed. There were statistically significant differences of CT density, SAC, EAN, HAP and FAT among the five groups(p<0.05), except the FAT value between group1 and group5 as well as between group 2 and group5. The concentrations of serum biomarkers were significantly higher in subjects with coronary atherosclerotic plaques than those in subjects without coronary plaques(p<0.05). There were significant differences of the MMP-9 concentrations between group2 and group3 as well as between group3 and group5(p<0.05). Negative correlations were found as follow: MMP-9 concentration vs. CT density(r=-0.501, p<0.05), MMP-9 concentration vs. EAN(r=-0.372, p<0.05), MMP-9 concentration vs. SAC(r=-0.378, p<0.05) and MMP-9 concentration vs. HAP material density(r=-0.411, p < 0.05). Positive correlation was found between serum MMP-9 concentration and FAT material density(r=0.34, p<0.05). ROC curves showed cutoff value and area under the curve(AUC) of SAC and EAN and HAP material was 3.41(AUC=0.633) and 8.91(AUC=0.652) and 96.07(AUC=0.648) between group 2 and group 5.Conclusion: The results indicate that spectral CT might be promising in differentiating different kinds of atherosclerotic plaques. These four kinds of spectral CT parameters are associated with serum MMP-9 level. |
PDF Full Text Request