Feasibility of low radiation dose and low contrast dose for coronary CT angiography in obese patients / 中华放射医学与防护杂志

Objective:To evaluate the feasibility of low radiation dose and low contrast dosage in coronary CT angiography (CCTA) of class I obese patients.Methods:This prospective study enrolled 57 patients (male/female, 50/7, age, 25-77 years) with body mass index (BMI) of 30-38 kg/m 2 and body weight of 85-119 kg scheduled for CCTA from August 2022 to March 2023 in our hospital. The patients were divided into two groups: control group (group A, n = 20) and low-dose group (group B, n = 37). Group A employed a standard-dose protocol: tube voltage 120 kVp and IDR 2.2 g I/s, while group B were scanned using the low-dose protocol: tube voltage 100 kVp and IDR 1.5 g I/s. Images in Group A and Group B were reconstructed with hybrid iterative reconstruction (HIR) at strength 4 and 8, respectively. Other scanning and reconstruction parameters were the same in two groups. Methods:The image quality was assessed by measuring the CT values and noise in the aortic root, left anterior descending artery and right coronary artery, and the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Subjective image quality was evaluated for vessels according to the 18-segment classification system using a 4-point scale (1. poor, 4. excellent). The effective dose E and contrast dosage were compared. Statistical analysis was performed using independent samples t-test, Mann-Whitney U test or χ 2 test. Results:The BMI of groups A and B were 31.89 (30.77, 33.81) and 31.22 (30.46, 32.83) kg/m 2, respectively ( P>0.05). No statistically significant differences in CT values, noise, SNR, CNR were noticed between the two groups (all P>0.05). The mean subjective score of all coronary artery segments in the two groups were not less than 3, meeting the requirement of clinical diagnosis. There was no statistically significant difference in the overall subjective image quality between the two groups ( P>0.05). The radiation dose E in groups A and B were 7.58 and 4.49 mSv, respectively ( Z=-5.46, P<0.05). The contrast dosage in groups A and B were 66 and 45 ml, respectively. The radiation dose E and contrast dosage in group B were 41% and 32% lower than that in group A, respectively. Conclusions:For class I obese patients, it was feasible to use a low tube voltage (100 kVp) and low IDR (1.5 gI/s) protocol in CCTA. Radiation dose and contrast dosage can be reduced reasonably without compromising the CCTA image quality.

Impact of calcification on the diagnostic accuracy of quantitative flow fraction based on coronary CT angiography / 中华放射学杂志

Objective:To investigate the effect of calcification on the diagnostic accuracy of the quantitative flow fraction (CT-QFR) derived from coronary CT angiography (CCTA).Methods:A total of 244 patients (471 coronary arteries) who underwent both CCTA and invasive coronary angiography (ICA) for suspected coronary artery disease between 2019 and 2021 were included in the study. All analyses were conducted at the vessel level using CCTA and ICA images, and the morphological and hemodynamic parameters of all enrolled vessels were assessed. The group was divided into severe calcification (206 cases) and non-severe calcification (265 cases) based on whether the arc of lesion calcification was greater than 180°. Subsequently, the two groups were evaluated to the degree of coronary stenosis, the length of the target lesion, the length of calcification, the ratio of the length of calcification, the remodeling index of calcification, the quantitative flow fraction (QFR), the CT-QFR, and the distribution of the involved vessels. Pearson correlation analysis and the Bland-Altman scatterplot were used to analyze the correlation and consistency between CT-QFR and QFR values from different subgroups. The benchmark for coronary ischemia was QFR≤0.80, and the criteria for diagnosing coronary ischemia were CT-QFR≤0.80 and luminal stenosis≥50%, respectively, and the effectiveness of CT-QFR for coronary ischemia was evaluated by plotting the ROC curves in various calcification subgroups.Results:The degree of luminal stenosis, lesion length, calcification length ratio, and calcification remodeling index were substantially higher in the severely calcified group than in the non-severely calcified group (all P<0.05). The results of the Pearson correlation analysis demonstrated a significant association between CT-QFR and QFR in both the severe and non-severe calcification groups ( r=0.85, 95%CI 0.81-0.88, P<0.001; r=0.91, 95%CI 0.89-0.93, P<0.001); in contrast, the Bland-Altman analysis indicated that the CT-QFR and QFR measurements in the severely calcified group exhibited a high level of agreement, with a mean difference of -0.01 (95% limits of agreement -0.22 to 0.20) for measurements in the severely calcified group and 0 (95% limits of agreement -0.15 to 0.16). The specificity, positive predictive value, negative predictive value, and area under the curve (AUC) for the diagnosis of ischaemic lesions by CT-QFR and CCTA alone were lower in the severely calcified group than in the non-severely calcified group, but the difference in AUC between the two groups for CT-QFR was not statistically significant ( P>0.05), and the difference in AUC for the morphological assessment of CCTA was statistically significant. The diagnostic effectiveness of CCTA alone was considerably worse than the specificity and AUC of CT-QFR for the various calcified subgroups for the diagnosis of ischemic lesions (all P<0.001). Conclusions:Severe calcification somewhat affected the diagnosis of ischaemic lesions by CT-QFR, but there was still a high correlation and concordance between CT-QFR and QFR within the severely calcified group, and the diagnostic efficacy was significantly better than that assessed by CCTA morphology alone.

Application of one-beat acquisition with wide detector CT in coronary artery CT angiography of patients with atrial fibrillation / 西安交通大学学报(医学版)

【Objective】 To evaluate the effect of one-beat acquisition with wide detector CT on the image quality and diagnostic efficiency of coronary CT angiography (CCTA) in patients with atrial fibrillation. 【Methods】 A total of 52 consecutive patients with atrial fibrillation, including 31 males, (67.32±11.45) years old, who underwent CCTA from July 2022 to February 2023, were analyzed retrospectively. All patients underwent one-beat acquisition CCTA. The subjective and objective image quality of the coronary arteries was evaluated, and using invasive coronary catheter angiography as the gold standard, the diagnostic efficacy of stenosis degrees above moderate and severe degrees was calculated, respectively. 【Results】 Subjective evaluation results: 92.31% (384/416) of the vascular segments were rated as excellent or good, and the diagnosable rate reached 98.08% (408/416, subjective score ≥3 points). Objective evaluation results: The CT value of the right coronary artery, anterior descending branch, and circumflex branch was (433.41±95.17)HU, (422.69±92.81)HU and (420.27±95.43)HU, respectively; the contrast-to-noise ratio was 38.46±7.54, 32.46±13.78 and 37.74±8.89, respectively. The total diagnostic accuracy, sensitivity, and specificity was 94.71%, 87.9% and 96.62%, respectively, for moderate stenosis and 96.15%, 83.64% and 98.06% for severe stenosis. 【Conclusion】 One-beat acquisition with wide detector CT can obtain high-quality coronary artery images and high diagnostic accuracy for patients with atrial fibrillation without radiation dose increase to patients. It has good clinical application value for patients with atrial fibrillation.

Cardiac allograft vasculopathy after heart transplantation: summary of a single-center long-term follow-up experience in Fuwai Hospital / 器官移植

Objective To summarize the incidence of cardiac allograft vasculopathy (CAV) after heart transplantation and the effect on the long-term survival of recipients. Methods Clinical data of 1 006 heart transplant recipients were retrospectively analyzed. Of 48 CAV patients, 4 cases were not included in this analysis due to lack of imaging evidence. A total of 1 002 recipients were divided into the CAV group (n=44) and non-CAV group (n=958) according to the incidence of CAV. The incidence of CAV was summarized. Clinical data of all patients were statistically compared between two groups. Imaging diagnosis, coronary artery disease, drug treatment and complications, postoperative survival and causes of death of CAV patients were analyzed. Results Among 1 006 heart transplant recipients, 48 cases (4.77%) developed CAV. Compared with the non-CAV group, the proportion of preoperative smoking history, preoperative hypertension history, coronary artery disease and perioperative infection was significantly higher in the CAV group (all P < 0.05). Among 44 patients diagnosed with CAV by imaging examination, 24 cases were diagnosed with CAV by coronary CT angiography (CTA), 4 cases by coronary angiography (CAG), and 16 cases by coronary CTA combined with CAG. Among 44 patients, the proportion of grade Ⅰ CAV was 45% (20/44), 30% (13/44) for grade Ⅱ CAV and 25% (11/44) for grade Ⅲ CAV, respectively. All patients received long-term use of statins after operation, and 20 patients were given with antiplatelet drugs. Among 44 CAV patients, 11 patients underwent percutaneous coronary intervention, 6 cases received repeated heart transplantation, and 8 patients died. Kaplan-Meier survival analysis demonstrated that there was no significant difference in the long-term survival rate between the CAV and non-CAV groups (P > 0.05), whereas the survival rate of patients tended to decline after the diagnosis of CAV (at postoperative 6-7 years). The long-term survival rates of patients with grade Ⅰ, grade Ⅱ and grade Ⅲ CAV showed no significant difference (P > 0.05). Even for patients with grade Ⅰ CAV, the long-term survival rate tended to decline. Conclusions CAV is a common and intractable complication following heart transplantation, and the long-term survival rate of patients after the diagnosis of CAV tended to decline. Deepening understanding of CAV, prompt prevention, diagnosis and treatment should be delivered to improve the long-term survival rate of patients after heart transplantation.

Preliminary study on motion artifacts removal of coronary CT angiography using generative adversarial network / 上海交通大学学报（医学版）

Objective: To investigate the ability of generative adversarial network (GAN) to remove motion artifacts in coronary CT angiography (CTA) images. Methods: Subjects who underwent single-cardiac-cycle multi-phase CTA were included and divided into training and test group. The middle segment of the right coronary artery (RCA) was investigated because its motion artifact is the most prominent among all coronary branches. The patch image of the vessel with motion artifacts was extracted, and paired images without artifacts were considered as reference. The GAN model was established according to the training group. In the test group, vessel images were segmented out of the surrounding tissues by using ITK-SNAP software, including the vessel with artifacts, GAN-generated images and reference images. The Dice coefficients of the vessel with artifacts vs reference image (dice1) and GAN-generated images vs reference image (dice2) were cal-culated. By comparing the difference between dice1 and dice2, GAN's ability in removing motion artifacts was evaluated. Results: Ninety subjects were included. Seventy-one (11 000 images) were randomly selected as the training group, and the other 19 (3 006 images) were as the test group. Based on subjects, dice1 and dice2 of the middle segment of RCA were 0.38±0.19 and 0.50±0.23, re-spectively (P=0.006). Based on images, the values of the middle segment of RCA were 0.38±0.20 and 0.51±0.26, respectively (P=0.000). Conclusion: GAN can significantly reduce the motion artifacts of CTA in the middle segment of RCA and has the potential to act as a new method to remove motion artifacts of coronary CTA images.

Correlation of Transluminal Attenuation Gradientdistal with Corrected Contrast Opacification with Anterior Coronary Atherosclerosis / 中国医学科学院学报

To explore the correlation between the transluminal attenuation gradient with corrected contrast opacification(TAG-CCO)and the severity of atherosclerotic stenosis in the anterior segment of myocrardial bridge(MB). The imaging data of 200 patients diagnosed with left anterior descending branch(LAD)single MB and coronary atherosclerosis in the anterior segment of MB were retrospectively analyzed.According to MB types,the patients were divided into two groups:incomplete and complete.There were some significant differences in TAG-CCO between patients with the same degree of coronary atherosclerosis(mild,moderate,and severe stenosis)in two groups.The relationships among groups with different degrees(mild,moderate,and severe stenosis)of the same type of MB were further compared. Among 84 patients with complete MB,36,30,and 18 patients had mild,moderate,or severe coronary atherosclerosis in the anterior segment of MB;among 116 patients with incomplete MB,45,42,and 29 patients had mild,moderate,or severe coronary atherosclerosis in the anterior segment of MB.In the complete MB group,the TAG-CCO in the anterior segment of MB subgroups were(-0.0086±0.0014)/10 mm,(-0.0170±0.0180)/10 mm,and(-0.0230±0.0026)/10 mm,respectively,in mild,moderate,and severe subgroups( = 404.728, <0.001).In the incomplete MB group,the TAG-CCO of patients with mild,moderate and severe coronary stenosis in the anterior segment of MB were(-0.0039±0.0011)/10 mm,(-0.0100±0.0140)/10 mm,and(-0.0160±0.0020)/10 mm,respectively,and the difference among the different stenosis groups was statistically significant( = 17.756, < 0.001);the TAG-CCO of patients with mild( = 16.519, < 0.001),moderate( = 2.570, = 0.012)and severe anterior segment coronary stenosis( = 10.714, < 0.001)were significantly lower in the complete MB group than in the incomplete MB group. TAG-CCO is correlated with the MB type and the degree of anterior coronary artery stenosis.Thus,TAG-CCO can be used as a predictive indicator for the degree of atheroscleratic stenosis in the anterior segment of MB.

In Vivo Detection of Lipid-Core Plaques by Coronary CT Angiography: A Head-to-Head Comparison with Histologic Findings

200 µm, a circumference > 60 degrees, and a cap thickness < 450 µm. The percentage distributions of CT pixel attenuation ≤ 20, 30, 40, and 50 HU were calculated using quantitative histogram analysis.RESULTS: A total of 271 transverse sections were co-registered between CCTA and pathological analysis. Overall, 26 lipid cores and 16 fibrous plaques were identified by pathological analysis. There was no significant difference in median CT attenuation between the lipid and fibrous plaques (51 HU [interquartile range, 46–63] vs. 57 HU [interquartile range, 50–64], p = 0.659). The median percentage of CT pixel attenuation ≤ 30 HU accounted for 11% (5–17) of lipid-core plaques and 0% (0–2) of fibrous plaques (p < 0.001). The sensitivity and specificity of the method for diagnosing lipid plaques by the average CT pixel attenuation ≤ 30 HU were 80.8% and 87.5%, respectively. The area under the receiver operator characteristics curve was 0.898 (95% confidence interval: 0.765–0.970; 3.0% was the best cut-off value). The diagnostic performance was significantly higher than those of the average pixel CT attenuation percentages ≤ 20, 40, and 50 HU and the mean CT attenuation (p < 0.05).CONCLUSION: In in vivo conditions, with the pathological lipid core as the gold standard, quantification of the percentage of average CT pixel attenuation ≤ 30 HU in the histogram can be useful for accurate identification of lipid plaques.

Comparative study of using individualized contrast-medium injection protocol to improve contrast uniformity in coronary CT angiography / 西安交通大学学报(医学版)

Objective: To investigate the effect of individualized contrast administration in improving the enhancement homogeneity in vessels and image quality in coronary CT angiography (CCTA). Methods: Sixty CCTA patients were randomly divided into two groups with different contrast injection protocols: treatment group (n=30) was treated with weight-dependent injection protocol at 22 mg/(g•s) of idion, injection velocity=body mass×22/contrast agent concentration. Control group (n=30) was treated with a different injection protocol. The iodine flow rate in this group was determined by patient body mass index (BMI), iodine flow rate=1.2 g/s, 1.4 g/s and 1.6 g/s. Injection flow rate= iodine flow rate/contrast agent concentration. Theiohexol (350 mg/mL) was used in both groups, and the injection time was fixed at 10 s and contrast agent dose=injection velocity×injection time. The other scanning parameters were the same. The enhancement change rate in AS and the three major arteries was calculated for the patient population. The subjective image quality scores were also compared. Results: The change rates of vascular enhancement at interested blood vessels in treatment group (12.9%, 11.8%, 11.0% and 11.1%, respectively) were significantly lower than those in in control group (23.3%, 18.7%, 16.7% and 20.5%, respectively) (P=0.001). There was no significant difference between the two groups in subjective image quality score (P=0.095). Conclusion: Individualized contrast injection protocol in CCTA can provide us with a more uniform enhancement in coronary arteries, and improve the overall image quality.

Subclinical Coronary Atherosclerosis: Implication of Coronary Computed Tomography Angiography Findings among Statin Candidates according to the 2013 ACC/AHA Cholesterol Management Guidelines

OBJECTIVE: To analyze the cardiovascular outcome of statin medication in individuals retrospectively categorized on the basis of the 2013 American College of Cardiology and American Heart Association (ACC/AHA) guidelines risk assessment and to determine the additional prognostic value of coronary computed tomography angiography (CCTA) in assessing cardiovascular disease (CVD) risk in this group. MATERIALS AND METHODS: This retrospective study reviewed 4255 asymptomatic individuals who had undergone self-referred CCTA with a median follow-up period of 87 months. The primary endpoint was major adverse cardiac events (MACEs); these included cardiac death, nonfatal myocardial infarction, and unstable angina. Individuals recommended for statins according to the ACC/AHA guidelines were analyzed by their assessed risk. RESULTS: MACE occurrence was significantly higher in the statin-recommended (SR) group with significant coronary artery disease (CAD) than in those with insignificant CAD (p < 0.001). In individuals with a normal coronary artery on CCTA, MACEs did not occur regardless of statin medication. In the SR group with significant CAD, there was no significant difference between statin users and non-users (p = 0.810). However, in cases with insignificant CAD, the event-free survival was significantly lower among statin users (p = 0.034). In patients recommended for moderate-intensity statins, the segment involvement score on CCTA was significantly associated with a higher risk of MACEs (hazard ratio 2.558; p = 0.001). CONCLUSION: CCTA might have a potential role in CVD risk stratification among asymptomatic statin candidates.

Modified Subtraction Coronary CT Angiography with a Two-Breathhold Technique: Image Quality and Diagnostic Accuracy in Patients with Coronary Calcifications

OBJECTIVE: To evaluate a modified subtraction coronary computed tomography angiography (CCTA) technique with a two-breathhold approach in terms of image quality and stenosis grading of calcified coronary segments and in the detection of significant coronary stenosis in segments with severe calcification. MATERIALS AND METHODS: The institutional board approved this study, and all subjects provided written consent. A total of 128 patients were recruited into this trial, of which 32 underwent subtraction CCTA scans and invasive coronary angiography (ICA). The average Agatston score was 356 ± 145. In severely calcified coronary segments, the presence of significant (> 50%) stenosis was assessed on both conventional CCTA and subtraction CCTA images, and the results were finally compared with ICA findings as the gold standard. RESULTS: For severely calcified segments, the image quality in conventional CCTA significantly improved from 2.51 ± 0.98 to 3.12 ± 0.94 in subtraction CCTA (p < 0.001). In target segments, specificity (70% vs. 87%; p = 0.005) and positive predictive value (61% vs. 79%, p < 0.01) were improved using subtraction CCTA in comparison with conventional CCTA, with no loss in the negative predictive value. The segment-based diagnostic accuracy for detecting significant stenosis was significantly better in subtraction CCTA than in conventional CCTA (area under the receiver operating characteristic curve, 0.94 vs. 0.85; p = 0.03). CONCLUSION: This modified subtraction CCTA method showed lower misregistration and better image quality in patients with limited breathhold capability. In comparison with conventional CCTA, modified subtraction CCTA would allow stenosis regrading and improve the diagnostic accuracy in coronary segments with severe calcification.

The value of individualized contrast agent injection regimen in coronary CTA imaging based on body surface area and body weight / 解放军医学杂志

Objective To explore the effect of individualized contrast agent injection regimen on coronary artery enhancement based on body surface area (BSA) and body weight (BW).Methods Totally 300 patients with suspected coronary heart disease from January to December 2016 in our hospital were randomly divided into three groups:control group (the injection volume and flow rate were fixed),BSA adjustment group and BW adjustment group.The patients were detected by CTA,and the degree and quality of coronary artery enhancement,the amount and flow rate of contrast agent,and the safety were analyzed in the three groups.Results The coronary artery enhancement value of the BSA adjustment group and the BW adjustment group was significantly higher than that of the control group (P＜0.05).The coronary enhancement in the BSA adjustment group was significantly higher than that of the BW adjustment group.Moreover,the standard deviation of the BSA adjustment group was significantly lower than that of the BW adjustment group (P＜0.05).The CTA score of the BSA adjustment group was significantly higher than that of the control group (P＜0.05).However,there was no significant difference between the BW adjustment group and BSA adjustment group or the control group (P＞0.05).The contrast agent dosage and flow rate was significantly higher in the control group than in the BSA adjustment group and BW adjustment group (P＜0.05).However,there was no significant difference between the BW adjustment group and BSA adjustment group (P＞0.05).Also,there was no significant difference in safety index between the three groups (P＞0.05).Conclusion The individualized contrast agent injection program based on BSA adjustment could not only reduce the amount of coronary imaging contrast agent and flow rate,but also improve the degree and effect of coronary artery enhancement.It could be expected to become a technical means for screening,early diagnosis,and even early intervention in early coronary heart disease.

Relationship between coronary atherosclerosis in coronary computed tomography angiography and serum vitamin D level

OBJECTIVES: Vitamin D deficiency has been shown to influence the development of some cardiovascular disease. In this study, the association between the existence of coronary artery plaque and vitamin D was examined among participants who were not previously diagnosed with coronary artery disease. METHODS: A total of 339 participants (246 men and 93 women) who visited a health examination center for check-up including blood test for serum vitamin D level and coronary computed tomography angiography (CCTA) were selected for this study. RESULTS: Among the total 339 participants, 106 displayed coronary artery plaques. The serum 25-hydroxy vitamin D (25(OH)D) level of the group with plaque was lower than that of the group without (17.7 ± 7.72 ng/mL vs. 19.6 ± 7.12 ng/mL, P = 0.0316). The group with plaque had higher incidence rates of diabetes mellitus, hypertension, and dyslipidemia than that without (P = 0.0078, P = 0.0065, and P = 0.0174, respectively). The former displayed higher serum glucose and glycated hemoglobin levels than the latter (P = 0.0055 and P = 0.0137, respectively). The group with plaque showed higher systolic and diastolic blood pressure than that without (P < 0.0001 and P = 0.0012, respectively). Stepwise multivariate logistic regression analysis revealed that 25(OH)D (coefficient, −0.06; odd ratio, 0.9433; 95% confidence interval, 0.8967–0.9924), age, and sex were independently related with presence of coronary artery plaque. CONCLUSIONS: Relatively low vitamin D level was observed among participants with plaque, which was determined through CCTA during a health examination. Plaque formation and serum 25(OH)D level showed inverse relationship.

High-Pitch Coronary CT Angiography at 70 kVp Adopting a Protocol of Low Injection Speed and Low Volume of Contrast Medium

OBJECTIVE: To evaluate the feasibility and image quality (IQ) of prospectively high-pitch coronary CT angiography (CCTA) with low contrast medium injection rate at 70 kVp. MATERIALS AND METHODS: One hundred and four patients with suspected coronary artery disease (body mass index < 26 kg/m², sinus rhythm and heart rate < 70 beats/min) were prospectively enrolled and randomly divided into two groups. In group A and group B, 28 mL and 40 mL of 370 mgI/mL iodinated contrast media was administrated at a flow rate of 3.5 and 5 mL/s, respectively. CT values, noise, signal-to-noise ratio, contrast-to-noise ratio (CNR) of the proximal segments of coronary arteries and subjective IQ were evaluated. RESULTS: The CT values and noise in group A were significantly lower than those in group B (434–485 Hounsfield units [HU] vs. 772–851 HU, all p < 0.001; 17.8–22.3 vs. 23.3–26.4, all p < 0.005). The CNRs of the right coronary artery and left main artery showed no statistical difference between the two groups (42.1 ± 13.8 vs. 36.8 ± 16.0, p = 0.074; 38.7 ± 10.6 vs. 38.1 ± 17.0, p = 0.819). No statistical difference was observed between the two groups in IQ scores (3.04 ± 0.75 vs. 3.0 ± 0.79, p = 0.526) and diagnostic ratio (96.1% [50/52] vs. 94.2% [49/52], p = 0.647). CONCLUSION: Prospective high-pitch CCTA at 70 kVp with 28 mL of contrast media and injection rate of 3.5 mL/s could provide diagnostic IQ for normal-weight patients with heart rate of < 70 beats/min.

High-Pitch Coronary CT Angiography at 70 kVp Adopting a Protocol of Low Injection Speed and Low Volume of Contrast Medium

OBJECTIVE: To evaluate the feasibility and image quality (IQ) of prospectively high-pitch coronary CT angiography (CCTA) with low contrast medium injection rate at 70 kVp. MATERIALS AND METHODS: One hundred and four patients with suspected coronary artery disease (body mass index < 26 kg/m², sinus rhythm and heart rate < 70 beats/min) were prospectively enrolled and randomly divided into two groups. In group A and group B, 28 mL and 40 mL of 370 mgI/mL iodinated contrast media was administrated at a flow rate of 3.5 and 5 mL/s, respectively. CT values, noise, signal-to-noise ratio, contrast-to-noise ratio (CNR) of the proximal segments of coronary arteries and subjective IQ were evaluated. RESULTS: The CT values and noise in group A were significantly lower than those in group B (434–485 Hounsfield units [HU] vs. 772–851 HU, all p < 0.001; 17.8–22.3 vs. 23.3–26.4, all p < 0.005). The CNRs of the right coronary artery and left main artery showed no statistical difference between the two groups (42.1 ± 13.8 vs. 36.8 ± 16.0, p = 0.074; 38.7 ± 10.6 vs. 38.1 ± 17.0, p = 0.819). No statistical difference was observed between the two groups in IQ scores (3.04 ± 0.75 vs. 3.0 ± 0.79, p = 0.526) and diagnostic ratio (96.1% [50/52] vs. 94.2% [49/52], p = 0.647). CONCLUSION: Prospective high-pitch CCTA at 70 kVp with 28 mL of contrast media and injection rate of 3.5 mL/s could provide diagnostic IQ for normal-weight patients with heart rate of < 70 beats/min.

On study of CCTA detection for epicardial adipose tissue and pericardial adipose tissue in the diagnosis of coronary stent restenosis / 中国医学装备

Objective:To research the application value of coronary CT angiography(CTA) detection for epicardial adipose tissue(EAT) and pericardial adipose tissue(PAT) in the diagnosis of coronary stent restenosis.Method:Selected 68 cases coronary atherosclerotic stenosis patients who were treated by coronary stent from June 2012 to June 2013 in hospital. All patients were detected after the operation of CTA within 3 years and they were divided into two groups (coronary stent restenosis positive group included 29 cases, negative group included 39 cases). To analyze the relationship between EAT and PAT through the statistical method and analyze the application value of EAT and PAT in the diagnosis of coronary stent restenosis based on calcification score image measurement of EAT and PAT volume.Results: Correlation analysis results showed there was correlation between EAT volume and PAT volume (r=0.859,P<0.05); through compared CAG and the diagnostic results of coronary artery stent restenosis by EAT and PAT, the sensitivity was 82.87%, specificity was 84.62%, CCTA positive predictive value was 80.00%, negative predictive value was 86.84% and diagnostic accuracy was 83.82% of the stent patency which was evaluated by CAG. The consistency evaluation marker Kappa was 0.554. The analysis of patients with coronary stent restenosis showed that there was significant correlation between Gensini score of coronary stent restenosis and EAT and PAT(P<0.05).Conclusion:There was significant correlation between EAT volume and PAT volume, and they can be used to evaluate the sensitivity and specificity of coronary stent operation restenosis and the results were higher. Besides, its clinical diagnostic value was similar with CAG.

Comparison of values of iDose4 iterative reconstruction and filtered back projection reconstruction for coronary CT angiography / 医疗卫生装备

Objective To explore the value of iDose4 iterative reconstruction for coronary CT angiography (CCTA).Methods Totally 124 coronary heart disease patients underwent iDose4 iterative reconstruction and filtered back projection (FBP) reconstruction,of whom,56 ones with BMI not less than 20 kg/m2 were put into No.1 iteration group using 135 kV tube voltage and 68 ones with BMI less than 20 kg/m2 were into No.2 iteration group using 110 kV tube voltage.FBP reconstruction was executed with 110 kV tube voltage.Comparison analyses were carried out on signal noise ratio (SNR),contrast to noise ratio (CNR) and image quality.Results There were significant differences between the values of SNR,radiation dose and image quality in No.1 iteration group and FBP group (P＜0.05).Statistical differences were also found between the values of CNR and radiation dose in No.2 iteration group and FBP group,while there were no obvious differences between the values of SNR and image quality in the above two groups (P＜0.05).Conclusion Low-voltage iDose reconstruction gains advantages in radiation dose and image quality during 64-slice CCTA,and thus is worthy promoting clinically.

Clinical & radiological evaluation of atherosclerotic changes in carotid & coronary arteries in asymptomatic & clinically symptomatic individuals as a tool for pre-symptomatic diagnosis of cardiovascular disease.

Background & objectives: An increase in prevalence of atherosclerosis has been noted worldwide with reports of higher incidence of atherosclerotic vascular changes in Asian Indians. There is a need to measure vascular atherosclerotic changes and provide objective parameter to predict cardiac and cerebrovascular adverse events. Atherosclerotic changes in carotids and coronaries are generally accepted as an association. We attempted in this study to relate intimal-luminal changes in carotid arteries to luminal changes in coronary arteries. Our study presents results of high resolution ultra sonographic (HRUS) evaluation of intimal-medial-thickness (IMT) in carotid with luminal changes in coronaries on multidetector-CT (MDCT) in clinically asymptomatic and symptomatic individuals. Methods: In this prospective study, HRUS examination of the carotid bifurcation was performed in 151 individuals to measure IMT in asymptomatic and symptomatic groups. Assessments of coronary arteries of the same group of patients were evaluated by MDCT within a week interval. IMT changes were associated with age, sex, predisposing factors, calcium burden of coronaries and structural atherosclerotic changes in coronary arteries. Results: A linear association of IMT was observed with increasing age. IMT of 0.5-0.69 mm was noted in 50 per cent of patients between 51-56 yr with higher number of symptomatic patients in this group. Linear increases in coronary vascular changes were noted with increasing IMT thickness. Changes were more prevalent in diabetic, hypertensive, treadmill test (TMT) positive and clinically symptomatic patients. Interpretation & conclusions: Age-related progression of atherosclerosis was evident in internal carotid arteries. Significant association was observed in the IMT thickness of right common carotid (RCC) and coronary disease in symptomatic group; whereas IMT of left common carotid and internal carotid arteries did not show any association. RCC IMT between 0.5-0.7mm showed maximal association with significant symptomatic narrowing of coronary arteries. Patients with IMT beyond 0.7mm had no association with symptoms.

Association of Homocysteine Levels with Subclinical Coronary Atherosclerosis in Asymptomatic Subjects

BACKGROUND: Progression of atherosclerotic plaques is known to be correlated with elevated circulating homocysteine (Hcy). However, whether the level of Hcy is related with coronary atherosclerosis in the subclinical state is unclear. Therefore, we performed this study to investigate the relationship between blood Hcy levels and subclinical atherosclerosis in asymptomatic self-referred subjects. METHODS: We retrospectively enrolled 2,968 self-referred asymptomatic subjects (1,374 men, 1,594 women) who had undergone both coronary CT angiography (CCTA) and coronary artery calcium scoring. The relationships between atherosclerosis, Hcy, and other clinical factors were assessed. RESULTS: Higher levels of Hcy were related with age, male gender, body mass index (BMI), waist circumference, blood pressure, high density lipoprotein (HDL), triglyceride, blood glucose, HbA1c, hsCRP, and coronary artery calcium score (CACS). Coronary plaque was more frequently found in higher Hcy quartile groups (21.3%, 28.8%, 34.4%, and 34.3%, P50%) was also more frequent in higher Hcy quartile groups (1.8%, 5.4%, 5.0%, and 6.6%, P400) than the first quartile group. CONCLUSIONS: Blood Hcy levels were associated with an increased risk of the presence and extent of subclinical atherosclerosis in asymptomatic subjects.

Cardiac Computed Tomographic Angiography: Clinical Applications.

Cardiovascular disease is the leading cause of morbidity and mortality worldwide. Cardiac imaging plays an important role in diagnosis and risk stratification of various cardiac diseases. Cardiac computed tomography added a major diagnostic value and led to reducing the need for invasive cardiac measures in many cardiac conditions. Cardiac computed tomography has emerged as an accurate anatomic method for detection of coronary artery disease. The negative predictive value to exclude significant coronary artery stenosis approaches 100%. Advances in multidetector computed tomography technology improved coronary arteries imaging during a single breath hold in a wide range of coronary pathologies. Appropriate patient preparation, image acquisition, and post processing techniques to detect coronary artery stenosis and plaque are prerequisites to achieving diagnostic image quality. Cardiac computed tomography applications also include assessment of cardiac structure and function, post myocardial infarction complications, electro anatomical mapping, and delineation of the pericardium.

How to Utilize Coronary Computed Tomography Angiography in the Treatment of Coronary Artery Disease

Coronary computed tomography angiography (CCTA) has high negative predictive power for detecting coronary artery disease. However CCTA is limited by moderate positive predictive power in the detection of myocardial ischemia. This is not unexpected because the diameter of a stenosis is a poor indicator of myocardial ischemia and discrepancy between the severity of stenosis and noninvasive tests is not uncommon. The value of stenosis for predicting future development of acute coronary syndrome represented by plaque rupture has been questioned. CCTA identifies the characteristics of high-risk plaque including positive remodeling, low density plaque and spotty or micro-calcification. Also, additional evaluation of myocardial ischemia using computational flow dynamics, and luminal attenuation gradient are expected to increase both diagnostic performance for hemodynamically significant stenosis and the predictive power for future cardiovascular risk. Technical advances in CCTA would enable evaluation of both coronary artery stenosis and myocardial ischemia simultaneously with high predictive performance, and would improve vastly the clinical value of CCTA.