Objective To evaluate the feasibility of dual energy spectral CT with 270 mg/ml iodixanol in coronary CT angiography (CCTA).Methods A total of 60 patients with suspected coronary heart disease underwent CCTA.They were randomly divided into 3 groups.Prospectively ECG gated CCTA with 120 kVp were performed on the controlgroup (Group A,n=20).In group B (n=20) and group C (n=20),gemstone spectral imaging(GSI) technique were used and monochromatic images from 60 to 80 keV with increment of 5 keV were obtained to divide into 5 subgroups(B1-B5,C1-C5).Group A and group B used the same contrast medium (iodixanol 350 mg/ml) while Group C used low concentration contrast medium (iodixanol 270 mg/ml).One-way ANOVA analysis was used to compare objective evaluation indices (CT values,image noise,signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the left main coronary artery,proximal segment of left anterior descending branch,proximal segment of left circumflex branch and proximal segment of right coronary artery) of group A and B1-B5.Statistical t-test was performed between group A and C2(with optimal keV).Results CNR of the group B1-B5[(21.2± 3.4),(21.5 ±4.0),(21.5 ±4.0),(21.8 ±4.2),(20.7 ± 3.5)]were increased significantly than group A(16.6± 3.8).No significant differences were found among groups B 1-B4 (P＞0.05).Compared withgroup A,group B2 showed higher CT values of the vessels [(481.4±43.2),(466.7±69.3),(434.1±48.8),(436.3±42.5),(427.4±48.6)HU] and decreased image noise[(28.2±7.3)HU versus (31.1±9.9) HU,P＜0.01].The optimal keV was 65 keV.Compared with group A,group C2 showed no significant differences in CT values[(396.3± 76.3),(390.4 ± 74.4),(359.5±83.1),(358.3±67.7),(365.4±68.2)HU)],image noise[(29.1±5.6)HU],SNR(14.6±4.2) and CNR [(18.4±4.8),t=-1.29-1.40,P＞ 0.05].Conclusion Dual-energy spectral CT with monochromatic reconstruction at 65 keV can provide same good image quality as the routine method while reduce iodine concentration to 270 mg/ml.

Objective To evaluate beam-hardening (BH) artifact reduction of myocardium in coronary computed tomography angiography(CCTA)with single-source dual-energy CT. Methods Thirty patients received CCTA on single-source dual-energy CT with findings of coronary artery stenosis<50%were enrolled in this study prospectively. Scanning mode was gemstone spectral imaging (GSI), single-source instantaneous(0.5 ms)kVp(140 kVp and 80 kVp)switch. The original images acquired by scanning were
reconstructed into monochromatic energy (60,70,80,90,100,110,120,130,140 keV) left vertical short-axis images via 40% ASIR and the polychromatic left vertical short-axis images were conventionally reconstructed. CT values were measured across multiple segments (basal anterior, basal lateral, basal inferior , basal septal, mid anterior, mid lateral, mid inferior , mid septal, apical anterior, apical lateral, apical inferior , apical septal and apex)of left ventricle wall at varying monochromatic energy levels and polychromatic images, and then the left ventricular myocardial average CT value and BH objective value were calculated retrospectively:BH1=CT value of mid inferior wall-CT value of basal inferior wall ,BH2=CT value of mid septal wall-CT value of mid inferior wall. BH subjective rating were evaluated by two radiologists independently. Single sample t test was used to compare the difference of myocardial CT values among 13 segments with the left ventricular myocardial average CT value on polychromatic images ;Kruskal-Wallis test was used to compare the difference of CT values among thirteen different segments of myocardium on fixed monochromatic energy images; Wilcoxon rank test was used to compare the difference of BH objective value and subjective rating between monochromatic images with polychromatic images. Results On polychromatic images, the mean myocardial CT value was(73 ± 25)HU, the CT value of basic inferior[(58±23)HU], basic septal[(85±21)HU], mid septal[(89±24)HU], apical anterior[(64±23)HU]and apex [(61 ± 24)HU ] were different from the mean myocardial CT value(t value were -3.76,2.89,3.50,-2.30, -2.86,P all<0.05),the differences of CT value between other myocardial segments and the mean myocardial CT value had no statistical significance(P all>0.05). The differences of CT value of different myocardial segments had statistical significance at 60 to 80 keV images(P all<0.05), the differences of CT value of different myocardial segments had no statistical significance at 90 to 140 keV images(P all>0.05), suggesting that the non-uniformity of CT value among different segments was improved. On polychromatic images,BH1 M(P25,P75)was 11(6,28),BH2 M(P25,P75)was 19(1,29) HU. BH1 was improved on 90 to 140 keV images while BH2 was improved on 70 to 140 keV images, the difference had statistical significance compared with the polychromatic images(P all<0.05). BH1,BH2 decreased with the increasing of monochromatic energy level on 60 to 100 keV images, then increased a little on 110,120 keV images, and hit bottom on 130 keV images with the value of 5.20,0.34 HU ,finally exist a slight increase on 140 keV images again. On polychromatic images,BH1,BH2 subjective rating M(P25,P75)both were 1(1,2), BH1 subjective rating was improved on 70 to 140 keV images while BH2 subjective rating was improved on 90 to 140 keV , the difference had statistical significance compared with the polychromatic images(P all<0.05). Conclusion Compared with the polychromatic images,monochromatic energy images of CCTA with dual-energy CT resulted in significant BH artifact reduction and improvements in the uniformity in the myocardium, and 130 keV is the optimal Monochromatic energy.

Objective To analyze the imaging findings of coronary angiography using 64-slice row CT and investigate the difference of coronary artery's morphological characteristics between Uygur and Han populations.Methods A retrospective study was made to coronary CT angiographic images of 88 Uygur cases matched with 88 Han cases.The data were analyzed with X~2 test and paired Wilcoxon test.Results The coronary CT angiographic findings were different between Uygur population and Han population in the following aspects: there were 62, 18, and 8 cases with the left coronary artery originating from intra-sinus, para-sinus and extra-sinus location respectively in Uygur population, while there were 73, 14, and 8 cases in Han population respectively (t=8319, P<0.05).And there were 78,7, and 3 cases with the right coronary artery originating from intra-sinus, para-sinus and extra-sinus location respectively in Uygur population, while there were 82, 1 and 1 case respectively in Han population (t=6936, P<0.05).The incidence of the sharp marginal branch were 52 (52.09%) and 67 (76.13%) in the two populations respectively (X~2=5.8381, P<0.05).The cases with various malformations of coronary arteries were 16 and 6 cases in the two populations respectively(X~2 =5.1948,P<0.05).The cases with LCA variations were 28 and 49 cases in the two populations respectively(t =2692,P<0.05) and the number with RCA variations were 33 and 27 cases in the two populations respectively(2 =968,P<0.05).Conclusions There are lots of differences of the coronary artery morphology between the Uygur and Han populations.Firstly, these differences may be related to different patterns in coronary angiography.Secondly, these differences may be related to differences between Uygur and Han populations in the incidence and severity of coronary heart disease.

Objective To study the feasibility of dual-source CT with dual-energy imaging based on single contrast enhancement. Methods The clinical data of 60 cases of patients who underwent dual-energy CT (DECT)examination of the heart in our hospital were analyzed.statistically.Results The success rate of 60 cases were 100% for displaying all 600 coronary artery segments at all stages.The total mean score of image quality was 4.68 ±0.57,and the good image rate reached 95%.6 cases of patients who ac-cepted DSA examination were unanimous with DECT findings;In 6 cases of patients who accepted SPECT examination,60 segments were no perfusion abnormalities,but DECT iodine figures of 54 segments were normal,and 6 segments showed perfusion defect. Conclusion DECT with dual-energy imaging based on single contrast enhancement can get excellent coronary and myocardial perfu-sion imaging in the circumstance of appropriate heart rate,which has some potentials for clinical application.

Objective To analyze the incidence of coronary myocardial bridge (MB) of the Uyghur and Han peoples with 64-slice CT. Methods A total of 1350 patients with suspected of coronary disease or other diseases underwent coronary angiography with 64-slice CT, among them 341 patients were diagnosed as MB, including 260 Han people, 70 Uyghur people, 7 Muslim people and 4 people of Kazak ethnic minority group. The incidence of MB of the Uyghur and Han people was calculated respectively; incidence of MB in proximal, middle and distal segment of left anterior descending (LAD), the first diagonal branch (D1), the second diagonal branch (D2), obtuse marginal (OM), left circumflex (LCX) and right coronary artery (RCA) between two races were compared with Chi-Square test. Results Totally 341 patients had 439 MB, 332 in Han people, 92 in Uyghur people, 9 in Muslim people and 6 in Kazak ethnic minority group with 64-slice CT. There was no statistical significance of MB incidence between the Uyghur and Han people in coronary artery (P＞0.05), including the proximal, middle and distal segment of LAD. Conclusion The 64-slice CT can effectively detect MB with a high special resolution. There is no statistical significance of MB incidence between the Uyghur and the Han people in each coronary artery.

BACKGROUNDThe incidence of congenital coronary artery anomalies (CCAAs) is different between ethnic groups, but there is no report about Uyghur CCAAs because of the limitation of inspection methods. This study determined the prevalence of Uyghur CCAAs and analysis the difference of CCAAs between Uyghur and Han ethnic groups by the method of multi-slice computed tomography coronary angiography (MSCTCA).

METHODSSeven thousand four hundred and sixty-nine MSCTCA were analyzed for the CCAAs retroactively, 1934 were Uyghur patients while 4746 were Han patients. All the coronary artery images dates obtained by MSCTCA were evaluated for the CCAAs by two doctors.

RESULTSNineteen kinds of CCAAs were found: (1) The overall incidence of CCAAs was 2.72% (203/7469) among all patients, 2.34% (111/4746) among Han patients whereas a significant higher 3.93% (76/1934) among Uyghur patients (χ2 = 12.780,P < 0.05); (2) the incidence of CCAAs among male patients was 2.48% (76/3069) in Han while 4.33% (56/1293) in Uyghur (χ2 = 10.663, P < 0.05); (3) the incidence of CCAAs on the left side was 1.07% (51/4746) among Han patients while 2.17% (42/934) among Uyghur patients (χ2 = 12.047, P < 0.05); (4) among these 19 kinds of CCAAs, there were significant differences of the incidence of the following kinds of CCAAs between Uyghur and Han: Left coronary artery (LCA) high location (χ2 = 8.320, P = 0.004), right coronary artery (RCA) originate from left coronary sinus (χ2 = 5.450, P = 0.020), and RCA originate from left Coronary sinus + LCA high location (P = 0.024).

CONCLUSIONSThere exists some difference in CCAAs between Uyghur and Han ethnic groups. The CCAAs incidence of Uyghur is higher than that of Han, especially in male patients and on the left side; among all kinds of CCAAs, the incidence of LCA high location, RCA originate from left coronary sinus, RCA originate from left coronary sinus + LCA high locations of Uyghur is higher than Han.

Aged ; China ; Coronary Artery Disease ; diagnosis ; diagnostic imaging ; ethnology ; Coronary Vessel Anomalies ; diagnosis ; diagnostic imaging ; ethnology ; Ethnic Groups ; statistics & numerical data ; Female ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Tomography, X-Ray Computed

Objective To define the optimal enhancement scanning triggering threshold(ESTT)for both coronary and myocardial imaging of dual energy coronary computed tomography angiography (DE-CCTA).Methods One hundred of 135 patients who were going to receive DE-CCTA were enrolled in this study prospectively and equally assigned to five groups randomly of different ESTT as 100, 110, 120, 130 and 140 HU. Noise, signal-to-noise ratios (SNR), contrast-to-noise ratios (CNR), enhancement extent (EE) of coronary artery and myocardium, iodine concentration, beam hardening (BH) objective value and subjective rating of myocardium and EE of left ventricle (LV) were measured and compared between different group;and noise,SNR,CNR,EE of coronary artery and myocardium,iodine concentration and BH objective value of myocardium obey normal distribution and equal variance,so they were expressed as mean± standard deviation and compared with variance analysis of multiple independent samples, and pairwise comparison were done with SNK test.Myocardial BH subjective rating was ranked data,and was expressed as [median (P25, P75)], and compared with Kruskal-Wallis test, and pairwise comparison were done with Nemenyi test.Results Post contrast CT value of LAD,post contrast CT value and EE of LV chamber were different with different ESTT (F=3.471, 3.795, 3.132,and all P<0.05)Post contrast CT value of LAD was lower with 130 HU[(355.16±59.11)HU than ESTT of 100 HU[(404.9±49.0)HU].Myocardial BH value and subjective score were different with different ESTT(F=6.118,H=13.702,P all<0.05).Myocardial BH value was lower with ESTT of 130,140 HU[(8.8±12.4),(5.4±17.1)HU]than 100,110 HU[(24.2±17.7),(22.1± 11.6)HU].Myocardial BH subjective score was lower with ESTT of 130 HU[1.5(1.0,2.0)]than 110 HU[3.0 (2.0, 3.0)]. Post contrast CT value and EE of LV myocardium, noise, SNR and CNR of LAD and LV myocardium, EE of LAD were not different between group of different ESTT (P all>0.05). Conclusions ESTT could influence image quality of myocardium and coronary artery.One hundred and thirty HU is optimal ESTT of DE-CCTA for showing myocardium and coronary artery simultaneously during DE-CCTA on second generation dual-source CT with retrospective electrocardiogating technic and as monitoring position at aortic root.

Objective To investigate the effects of low contrast agent concentration and optimal monoenergetic image on myocardial image quality in dual source, dual energy coronary CT angiography (CCTA).Methods Sixty patients,who were clinically suspected of coronary heart disease and referred to perform dual energy CCTA examination,were prospectively collected between January and June 2016 in the first affiliated hospital of Xinjiang Medical University and then randomly divided into two groups with thirty cases in each group.Dual-energy CCTA was performed in both groups with the same parameters expect the iodine contrast agent concentration.The iopamidol concentrations were 370 and 320 mg/ml for groups A and B, respectively. The raw images of the two groups were reconstructed to get conventional mixed energy images and 60,65,70,75,80,85,90 keV single energy images,respectively labeled as group A1 to A8 and group B1 to B8.The CT attenuation,noise,signal-to-noise ratio(SNR)and contrast to noise ratio(CNR)were measured in images from groups A1 to A8 and B1 to B8. And the optimal monoenergetic image set was selected.Rank sum test was used to compare the CT value,noise,SNR and CNR between groups A1 to A8 and B1 to B8.The differences of above-mentioned parameters between A1 and B5 group,A5 group and B5 group were compared by independent sample t test.Results The differences of CT value,noise,SNR and CNR between groups A1 and A8, B1 and B8 were statistically significant (P<0.05). The CNR and SNR of group A5 were significantly higher than that of group A1,and the image noise of group A5 was lower than that of group A1(all P<0.05),and the images of A5 group(75 keV)were the optimal monoenergetic image. The SNR and CNR of the left ventricular lateral wall in group B5 were significantly higher than those in group B1,and the noise was lower than that in group B1(all P<0.05),and the image of B5 group(75 keV) was the optimal monoenergetic image. The difference of image noise between groups A1 and B5 was statistically significant(P<0.05),while the differences of SNR and CNR between these two groups were not significant(all P>0.05).The differences of image noise,SNR and CNR between groups A5 and B5 were not significant(all P>0.05).Conclusions The myocardial CCTA image quality by using iodine contrast agent (320 mg/ml) and optimal monoenergetic imaging (75 keV) is equivalent to that of conventional iodine contrast agent(370 mg/ml)mixed energy image.The strategy can effectively reduce the amount of contrast agent when meeting the needs of the clinical diagnosis.