Radiation dose analysis of computed tomography coronary angiography in Children with Kawasaki disease

BACKGROUND There is evolving role of computed tomography coronary angiography(CTCA)in non-invasive evaluation of coronary artery abnormalities in children with Kawasaki disease(KD).Despite this,there is lack of data on radiation dose in this group of children undergoing CTCA.AIM To audit the radiation dose of CTCA in children with KD.METHODS Study(December 2013-February 2018)was performed on dual source CT scanner using adaptive prospective electrocardiography-triggering.The dose length product(DLP in milligray-centimeters-mGy.cm)was recorded.Effective radiation dose(millisieverts-mSv)was calculated by applying appropriate age adjusted conversion factors as per recommendations of International Commission on Radiological Protection.Radiation dose was compared across the groups(0-1,1-5,5-10,and>10 years).RESULTS Eighty-five children(71 boys,14 girls)with KD underwent CTCA.The median age was 5 years(range,2 mo-11 years).Median DLP and effective dose was 21 mGy.cm,interquartile ranges(IQR)=15(13,28)and 0.83 mSv,IQR=0.33(0.68,1.01)respectively.Mean DLP increased significantly across the age groups.Mean effective dose in infants(0.63 mSv)was significantly lower than the other age groups(1-5 years 0.85 mSv,5-10 years 1.04 mSv,and>10 years 1.38 mSv)(P<0.05).There was no significant difference in the effective dose between the other groups of children.All the CTCA studies were of diagnostic quality.No child required a repeat examination.CONCLUSION CTCA is feasible with submillisievert radiation dose in most children with KD.Thus,CTCA has the potential to be an important adjunctive imaging modality in children with KD.

Emerging role of computed tomography coronary angiography in evaluation of children with Kawasaki disease

Coronary artery abnormalities are the most important complications in children with Kawasaki disease(KD).Two-dimensional transthoracic echocardiography currently is the standard of care for initial evaluation and follow-up of children with KD.However,it has inherent limitations with regard to evaluation of mid and distal coronary arteries and,left circumflex artery and the poor acoustic window in older children often makes evaluation difficult in this age group.Catheter angiography(CA)is invasive,has high radiation exposure and fails to demonstrate abnormalities beyond lumen.The limitations of echocardiography and CA necessitate the use of an imaging modality that overcomes these problems.In recent years advances in computed tomography technology have enabled explicit evaluation of coronary arteries along their entire course including major branches with optimal and acceptable radiation exposure in children.Computed tomography coronary angiography(CTCA)can be performed during acute as well as convalescent phases of KD.It is likely that CTCA may soon be considered the reference standard imaging modality for evaluation of coronary arteries in children with KD.

Clinical characteristics of different computed tomography coronary angiography plaque properties in patients with coronary artery disease

Objective: To study the clinical characteristics of different computed tomography coronary angiography (CTCA) plaque properties in patients with coronary artery disease. Methods:Patients who were diagnosed with coronary artery disease in Ankang Central Hospital between February 2015 and March 2017 were selected and divided into soft plaque group, mixed plaque group and calcified plaque group according to the plaque properties judged by CTCA examination, and healthy volunteers who received physical examination in Ankang Central Hospital during the same period were selected as control group. The serum levels of material metabolism indexes, cytokines as well as collagen synthesis and degradation indexes of the four groups were measured. Results: Serum UA, Hcy, PCSK9, LDL-C, GDF-15, CXCL5, hs-CRP, RANTES, IL-6, MMP1, ST2, CysC and I-CTP levels of soft plaque group, mixed plaque group and calcified plaque group were significantly higher than those of control group, serum UA, Hcy, PCSK9, LDL-C, GDF-15, CXCL5, hs-CRP, RANTES, IL-6, MMP1, ST2, CysC and I-CTP levels of soft plaque group and mixed plaque group were significantly higher than those of calcified plaque group, and serum UA, Hcy, PCSK9, LDL-C, GDF-15, CXCL5, hs-CRP, RANTES, IL-6, MMP1, ST2, CysC and I-CTP levels of soft plaque group were significantly higher than those of mixed plaque group. Conclusion: CTCA can accurately determine the plaque properties and evaluate the disorder of material metabolism, cytokine secretion as well as collagen synthesis and degradation during the change of plaque properties in patients with coronary artery disease.

Feasibility and accuracy of coronary imaging in elderly patients using the 64-row multi-detector computed tomography: a correlation study with conventional coronary angiography

Background Elderly patients generally have higher occurrence of coronary calcification, increased heart rate and difficulty with prolonged breath-holding. The aim of our study was to investigate the feasibility and accuracy of using 64-row multi-detector computed tomography (MDCT) in the assessment of coronary artery stenoses in elderly patients. Methods One hundred and fifty two patients with suspected or known coronary artery disease were divided into 4 groups according to their age (Group A: 40-49 years,n=34; Group B: 50-59 years, n=57; Group C: 60-69 years, n=48; Group D: 70 years and above; n=13). Coronary CT angiography (CTA) using a 64-row MDCT was performed and the findings were compared with that of conventional coronary angiography (CCA).Using axial images, multi-planar reconstructions (MPR) and maximum intensity projections (MIP), coronary segments of lumen diameter = 1.5mm were analyzed for the presence of significant stenosis (= 50% ). Results Percentages of poor image quality from coronary CTA preventing reliable correlations with CCA were 21%, 14%, 19% and 62% in Groups A to D respectively. Patients in Group D had significantly higher calcium scores compared with the other groups (P＜0.001). In patients where CTA images were of acceptable quality, percentages of accurate correlations with CCA were 89.8%, 93.4%, 86.6% and 78.0% for Groups A to D respectively.There were no significant difference in serum creatinine, heart rate and contrast volume between the 4 groups. Conclusions The 64-row MDCT coronary angiography was less accurate and feasible for patients aged 70 years or above due to heavy coronary calcification and inability to perform a satisfactory breath-hold. However, a high diagnostic accuracy with the MDCT is possible in patients aged less than 70 years.

Effects of combining multiple dose reduction techniques on coronary computed tomography angiography

BACKGROUND Coronary computed tomography angiography(CCTA)is the preferred noninvasive examination method for coronary heart disease.However,the radiation from computed tomography has become a concern since public awareness of radiation hazards continue to increase.AIM To explore the value of multiple dose reduction techniques for CCTA.METHODS Consecutive normal and overweight patients were prospectively divided into two groups:Group A1,patients who received multiple dose reduction scans(n=82);and group A2,patients who received conventional scans(n=39).The scan parameters for group A1 were as follows:Isocentric scan,tube voltage=80 kV,and tube current control using 80%smart milliampere.The scan parameters for group A2 were as follows:Normal position,tube voltage=100 kV,and smart milliampere.RESULTS The average effective doses(EDs)for groups A1 and A2 were 1.13±0.35 and 3.36±1.30 mSv,respectively.There was a statistically significant difference in ED between the two groups(P<0.01).Furthermore,noise was significantly lower,and both signal-to-noise ratio and contrast signal-to-noise ratio were higher in group A2 when compared to group A1(P<0.01).Moreover,the subjective image quality(IQ)scores were excellent in both groups,in which there was no significant difference in subjective IQ score between the two groups(P=0.12).CONCLUSION Multiple dose reduction scan techniques can significantly decrease the ED of patients receiving CCTA examinations for clinical diagnosis.

Machine learning for diagnosis of coronary artery disease in computed tomography angiography:A survey

Coronary artery disease(CAD)has become a major illness endangering human health.It mainly manifests as atherosclerotic plaques,especially vulnerable plaques without obvious symptoms in the early stage.Once a rupture occurs,it will lead to severe coronary stenosis,which in turn may trigger a major adverse cardiovascular event.Computed tomography angiography(CTA)has become a standard diagnostic tool for early screening of coronary plaque and stenosis due to its advantages in high resolution,noninvasiveness,and three-dimensional imaging.However,manual examination of CTA images by radiologists has been proven to be tedious and time-consuming,which might also lead to intra-and interobserver errors.Nowadays,many machine learning algorithms have enabled the(semi-)automatic diagnosis of CAD by extracting quantitative features from CTA images.This paper provides a survey of these machine learning algorithms for the diagnosis of CAD in CTA images,including coronary artery extraction,coronary plaque detection,vulnerable plaque identification,and coronary stenosis assessment.Most included articles were published within this decade and are found in the Web of Science.We wish to give readers a glimpse of the current status,challenges,and perspectives of these machine learning-based analysis methods for automatic CAD diagnosis.

Multislice computed tomography angiography in the diagnosis of coronary artery disease

Multislice CT angiography 表示在心脏的成像和它的最令人激动的工艺的革命之一逐渐地在冠的动脉疾病的诊断被使用了。在在最后十年的 multislice CT 扫描仪的快速的改进允许这种技术与怀疑的冠的动脉疾病在病人成为一种潜在地有效的选择到侵略冠的 angiography。高诊断的价值与 64- 和更多的片 CT 扫描仪的使用与 multislice CT angiography 被完成了。另外， multislice CT angiography 显示出冠的钙，冠的匾的描述，以及疾病前进和主要心脏的事件的预言的精确察觉和分析。因此，当避免不必要的侵略冠的 angiography 过程时，病人们能得益于提供快速、精确的诊断的 multislice CT angiography。这篇文章的目的是在场的在有冠的动脉疾病的诊断精确性的一个焦点的冠的动脉疾病的 multislice CT angiography 的临床的应用的概述；关于主要心脏的事件的预言的冠的动脉疾病的预示的价值；冠的匾的冠的钙和描述的察觉和 quantification。在冠的动脉疾病的 multislice CT angiography 的限制简短也被讨论，并且未来方向被加亮。

Relation between Epicardial Adipose Tissue Thickness Assessed by Multidetector Computed Tomography and Significance of Coronary Artery Disease

Objective: To evaluate the relation between epicardial adipose tissue (EAT) thickness and also pericoronary fat assessed by Multidetector Computed Tomography (MDCT) with both calcium score and significance of coronary artery disease. Background: Epicardial adipose tissue (the visceral fat of the heart present under the visceral layer of the pericardium) has the same origin of abdominal visceral fat, which is known to be strongly related to the development of coronary artery atherosclerosis. Multidetector CT (MDCT) provides an accurate and reproducible quantification of EAT due to its high spatial and temporal resolution. Patients and Methods: The current study included 70 patients with low-intermediate probability of coronary artery disease. All patients were subjected to 256 Multidetectors CT to assess EAT thickness, the mean thickness of the pericoronary fat surrounding the three coronary arteries and coronary calcium score. Also coronary CT angiography was done and patients were then divided into 3 groups according to significance of coronary atherosclerosis: Group 1: No atherosclerosis (20 patients), Group 2: Non obstructive atherosclerosis (luminal narrowing less than 50% in diameter) (25 patients), Group3: Obstructive atherosclerosis (luminal narrowing ≥ 50%) (25 patients). Results: The mean EAT thickness and the mean pericoronary fat thickness were significantly higher in patients with obstructive coronary artery disease (CAD) with stenosis > 50% (group 3) compared to other groups with normal coronaries or non obstructive (CAD). ROC curve was used to define the best cut off value of the thickness of both EAT and pericoronary fat in predicting the obstructive CAD group which was ≥7.2 and 12.6 mm for epicardial and pericoronary fat respectively. Also there is a positive correlation between both epicardial adipose tissue and pericoronary fat thickness and the coronary calcium score. Conclusion: EAT thickness and pericoronary fat thickness can be used in predicting the significance of coronary artery disease.

Artificial intelligence in coronary computed tomography angiography

Coronary computed tomography angiography(CCTA)is recommended as a frontline diagnostic tool in the non-invasive assessment of patients with suspected coronary artery disease(CAD)and cardiovascular risk stratification.To date,artificial intelligence(AI)techniques have brought major changes in the way that we make individualized decisions for patients with CAD.Applications of AI in CCTA have produced improvements in many aspects,including assessment of stenosis degree,determination of plaque type,identification of high-risk plaque,quantification of coronary artery calcium score,diagnosis of myocardial infarction,estimation of computed tomography-derived fractional flow reserve,left ventricular myocardium analysis,perivascular adipose tissue analysis,prognosis of CAD,and so on.The purpose of this review is to provide a comprehensive overview of current status of AI in CCTA.

Comparison of 16 slice multi-detector computed tomography and breath hold 3D magnetic resonance angiography in the detection of coronary stenosis

Objective To compare 16-slice multi-detector spiral computed tomography (MDCT) and breathhold 3D magnetic resonance (MR) coronary angiography in the visualization of coronary arteries and the accuracy of detecting significant (＞ 50%) coronary stenoses in patients with suspected coronary artery disease. Methods Forty patients were examined by 16-slice CT (GE, Lightspeedl6)and MR (GE,Twinspeed) within 3 days; 31 of them underwent conventional coronary angiography (CAG) within 2 weeks after CT and MR scan. CT was performed with 16× 1.25 mm detector collimation, 0.5 s rotation time and images were reconstructed at 60%-75% of the cardiac cycle. MR was performed with breath hold 3D FIESTA (TR4.0 ms, TE1.7 ms, flip angle 65, slice thickness 3 mm, FOV 280 mm, matrix 256× 192). Mean heart rate was 63 ± 5.8 bpm and β-blocker was used in 24 patients. MR and CT image quality was evaluated in 9 coronary segments (RCA1, RCA2, RCA3, LM, LAD1, LAD2, LAD3, LCX1, LCX2) using a four-point grading scale.Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were calculated for detection of significant stenosis using CAG as the gold standard. Results 16-slice CT showed higher image quality in most coronary segments except RCA2.Forty-three segments were diagnosed as significant stenosis by CAG, 36 and 27 of these were correctly detected by CT and MR respectively. Sensitivity, specificity, positive predictive value, and negative predictive value of 16-slice CT and MR for detecting significant stenosis were 83 %, 84 %, 49 %, 97 % and 63 %, 90 %, 55 %, 93 %, respectively. Conclusion Sixteen-slice CT showed higher image quality in most coronary segments excepted for middle RCA. 16-slice CT had higher sensitivity than MR for detection of coronary significant stenosis, whereas MR had higher specificity than CT. Both CT and MR showed high negative predictive value,which is useful for excluding coronary stenosis in symptomatic patients.

CORONARY ANGIOGRAPHY WITH DUAL SOURCE COMPUTED TOMOGRAPHY:INITIAL EXPERIENCE

Objective To explore the scan technique and image quality of coronary angiography with dual source computed tomography(CT) without oral metoprolol preparation.Methods Plain and enhanced dual source CT coronary angiography without oral metoprolol preparation was prospectively performed in 600 patients.Calcium scoring with plain scan images as well as multi-planar reconstruction(MPR),maximum intensity projection(MIP),and volume rendering technique(VRT) reconstruction with enhanced scan images were performed in all cases.The scan technique and post-reconstruction experience was summarized.The image quality was classified as 1 to 4 points,and coronary segments classified according to the American Heart Association standards were evaluated.Results The average calcium score of the 600 cases was 213.6±298.7(0-3 216.5).The average heart rate of the enhanced scan was 82.1±16.2(47-139) bpm.The post-reconstruction methods with which coronary segments could be shown as best as possible consisted of single phase reconstruction method,two or more phases supplemented method,and electrocardiogram editing method.Altogether 8 457 coronary segments were evaluated,among which 97.2% were evaluated as point 1,1.7% point 2,0.5% point 3,and 0.6% point 4.The coronary segments in 261 cases were completely normal,while 360 segments were diagnosed with <50% stenosis and 625 segments with ≥50% stenosis.Conclusions Excellent coronary artery image can be obtained with dual source CT in patients with any heart rate without oral metoprolol preparation.Heart rate is not a major source of the artifact,coronary segments can be well shown with single or multiple-phase reconstruction method.

Novel Approaches for the Use of Cardiac/Coronary Computed Tomography Angiography

Recent developments in the novel imaging technology of cardiac computed tomography(CT)not only permit detailed assessment of cardiac anatomy but also provide insight into cardiovascular physiology.Foremost,coronary CT angiography(CCTA)enables direct noninvasive examination of both coronary artery stenoses and atherosclerotic plaque characteristics.Calculation of computational fl uid dynamics by cardiac CT allows the noninvasive estimation of fractional fl ow reserve,which increases the diagnostic accuracy for detection of hemodynamically signifi cant coronary artery disease.In addition,a combination of myocardial CT perfusion and CCTA can provide simultaneous anatomical and functional assessment of coronary artery disease.Finally,detailed anatomical evaluation of atrial,ventricular,and valvular anatomy provides diagnostic information and guidance for procedural planning,such as for transcatheter aortic valve replacement.The clinical applications of cardiac CT will be extended with the development of these novel modalities.

Myocardial bridge-related coronary heart disease:Independent influencing factors and their predicting value

BACKGROUND Myocardial bridge(MB)will compress the mural coronary artery(MCA)during the systole and cause myocardial ischemia.In the diagnosis of coronary heart disease(CHD),because the structure of MB is difficult to be observed by coronary angiography(CAG),the clinical study of the influence of MB on CHD is lacking.With the advancement of computed tomography coronary angiography technology,detailed observations of the MB anatomy have realized.AIM To explore the main influencing factors of MB-related CHD and to find potential indicators for predicting MB-related CHD.METHODS A total of 1718 patients with suspected CHD due to the symptoms of myocardial ischemia were enrolled as subjects.Patients diagnosed with CHD were included in a CHD group,and patients with no significant abnormalities were included in a control group.In the CHD group,patients were divided into an MB-CHD subgroup if MB-related CHD was found.In the control group,patients were divided into a simple MB subgroup if MB was found.The patient's clinical data and MB-related indicators,including the branch of MB,MB type(superficial/deep type),MB length,MB thickness,systolic and diastolic compression of the MCA,and MCA systolic stenosis rate were recorded and compared.Logistic regression analysis was used to explore the independent influencing factors of MD-related CHD.ROC curve was used to analyze the diagnostic efficacy of potential indicators for MB-related CHD.RESULTS There were 1060 cases in the CHD group and 658 cases in the control group,and there were 236 cases in the MB-CHD subgroup and 52 cases in the simple MB subgroup.Multivariate logistic regression analysis showed that the combined MB had a significant effect on the occurrence of CHD(P<0.05).MB thickness,systolic compression,diastolic compression,and MCA systolic stenosis rate had significant effects on the occurrence of MB-related CHD(P<0.05).The area under the curve(AUC)of the combination of these influencing factors for the diagnosis of MB-related CHD was 0.959,which was significantly higher than the AUCs of the four indicators separately(P<0.05).The sensitivity was 97.06%and the specificity was 87.63%.CONCLUSION MB thickness,systolic compression,diastolic compression,and MCA systolic stenosis are independent influencing factors for MB-related CHD.The combination of these factors has potential diagnostic value for MB-related CHD.

64-row multi-dector computed tomography coronary image from a center with early experience: first illustration of learning curve

Background and objectives The recent joint ACCF/AHA clinical competence statement on cardiac imaging with multi-detector computed tomography recommended a minimum of 6 months training and 300 contrast examinations, of which the candidate must be directly involved in at least 100 studies. Whether this is adequate to become proficient in interpretation of coronary computed tomogsignificant coronary stenosis in a center with 1 year's experience using a 64-row scanner. Methods A total of 778 patients underwent contrast-enhanced CTA between January and December 2005. Out of these patients, 301 patients also underwent contrast-enhanced conventional coronary angiography (CCA). These patients were divided into 4 groups according to the time the examination was underwent. Group Q1: first quarter of the year (n=20), Group Q2: second quarter (n=128), Group Q3: third quarter (n=134), and Group Results The sensitivity, specificity, positive, and negative predictive values were Q1 - 64%, 89%, 49% and 94%, respectively; Q2 -79%, 96%, 74% and 97%, respectively; Q3 - 78%, 96%, 74%, 97%, respectively, and Q4 - 100% for all. Conclusions In a center with formal training and high caseload, our accuracy in CTA analysis reached a plateau after 6 months experience. Test-bolus protocols produce better image quality and can improve accuracy. New centers embarking on CTA will need to overcome an initial 6-month learning curve depending upon the caseload during which time they should consider correlation with CCA.

Noninvasive Detection of Coronary Artery Stenosis Using 16-slice Spiral CT: a Comparison with Selective X-ray Coronary Angiography

The role of 16-slice spiral CT was selective X-ray coronary angiography （SCA） who were suspected of having coronary heart evaluated in the diagnosis of coronary stenosis, with serving as the reference standard. Sixty-five patients disease, without percutaneous transluminal coronary angioplasty or coronary bypass-grafting, were investigated using 16-slice CT. Eight patients with pre-scan heart rate of more than 80 beats/min were given β-blockers. After the retrospectively ECG-gated axial imaging reconstruction, volume redering （VR）, multi-planar reconstruction （MPR）, curved MPR and maximum intensity projection （MIP） were used to reconstruct. Every segment of coronary artery with a diameter ≥1.5 mm was assessed, and the presence on CT with a stenosis exceeding 50 % diameter reduction was compared with that on SCA. The reasons which lead to some segments unevaluable were analysed. Compared with SCA, 93 % coronary segments and 94 % main branches were evaluable. Residual cardiac motion artifacts, severe calcification and poor opacification made 58 %, 28 % and 14 % of the remaining 60 segments unevaluable respectively. Without routine administration of β-blockers, good coronary imaging quality can be acquired using 16-slice spiral CT. It is a reliable noninvasive method for detection of obstructive coronary artery disease.

Triple rule-out computed tomography angiography:Evaluation of acute chest pain in COVID-19 patients in the emergency department

BACKGROUND The aim of this study was to define clinical evidence supporting that triple ruleout computed tomography angiography(TRO CTA)is a comprehensive and feasible diagnostic tool in patients with novel coronavirus disease 2019(COVID-19)who were admitted to the emergency department(ED)for acute chest pain.Optimizing diagnostic imaging strategies in COVID-19 related thromboembolic events,will help for rapid and noninvasive diagnoses and results will be effective for patients and healthcare systems in all aspects.AIM To define clinical evidence supporting that TRO CTA is a comprehensive and feasible diagnostic tool in COVID-19 patients who were admitted to the ED for acute chest pain,and to assess outcomes of optimizing diagnostic imaging strategies,particularly TRO CTA use,in COVID-19 related thromboembolic events.METHODS TRO CTA images were evaluated for the presence of coronary artery disease,pulmonary thromboembolism(PTE),or acute aortic syndromes.Statistical analyses were used for evaluation of significant association between the variables.A two tailed P-value<0.05 was considered statistically significant.RESULTS Fifty-three patients were included into the study.In 31 patients(65.9%),there was not any pathology,while PTE was diagnosed in 11 patients.There was no significant relationship between the rates of pathology on CTA and history of hypertension.On the other hand,the diabetes mellitus rate was much higher in the acute coronary syndrome group,particularly in the PTE group(8/31=25.8%vs 6/16=37.5%,P=0.001).The rate of dyslipidemia was significantly higher in the group with pathology on CTA while compared to those without pathology apart from imaging findings of the pneumonia group(62.5%vs 38.7%,P<0.001).Smoking history rates were similar in the groups.Platelets,D-dimer,fibrinogen,C-reactive protein,and erythrocyte sedimentation rate values were higher in COVID-19 cases with additional pathologies.CONCLUSION TRO CTA is an effective imaging method in evaluation of all thoracic vascular systems at once and gives accurate results in COVID-19 patients.

Feasibility and Diagnostic Accuracy for Assessment of Coronary Artery Stenosis of Prospectively Electrocardiogram-gated High-pitch Spiral Acquisition Mode Dual-source CT Coronary Angiography in Patients with Relatively Higher Heart Rates: in Comparison wit

Objective To prospectively investigate the diagnostic accuracy for coronary artery stenosis of prospectively electrocardiogram-triggered spiral acquisition mode (high pitch mode) dual-source computed tomography coronary angiography (CTCA) in patients with relatively higher heart rates (HR) compared with catheter coronary angiography (CCA). Methods Forty-seven consecutive patients with relatively higher HR (>65 and <100 bpm) (20 male, 27 female; age 55±10 years) who both underwent dual-source CTCA and CCA were prospectively included in this study. All patients were performed CTCA using high pitch mode setting at 20%-30% of the R-R interval for the image acquisition. All coronary segments were evaluated by two blinded and independent observers with regard to image quality on a three-point scale (1: excellent to 3: non-diagnostic) and for the presence of significant coronary stenoses (defined as diameter narrowing exceeding 50%). Considered CCA as the standard of reference, the sensitivity, specificity, positive predictive value and negative predictive value were calculated. Radiation dose values were calculated using the dose-length product. Results Image quality was rated as being score 1 in 92.4% of segments, score 2 in 6.1% of segmentsand score 3 in 1.5% of segments. The average image quality score per segment was 1.064±0.306. The HR variability of patients with image score 1, 2 and 3 were 2.29±1.06 bpm, 5.17±1.37 bpm, 8.88±1.53 bpm, respectively. The average HR variability of patients with different image scores were significantly different (F=170.402, P=0.001). The sensitivity, specificity, positive and negative predictive values were 92.6%, 97.0%, 87.6%, 98.3%, respectively, per segment and 90.0%, 95.2%, 85.3%, 96.9%, respectively, per vessel and 100%, 63.6%, 90.0%, 100%, respectively, per patient. The effective radiation dose was on average 0.86±0.16 mSv. Conclusion In patients with HR more than 65 bpm and below 100 bpm without cardiac arrhythmia, the prospectively electrocardiogram-gated high-pitch spiral acquisition mode with image acquired timing set at 20%-30% of the R-R interval provides a high diagnostic accuracy for the assessment of coronary stenoses combined with a 1.5% of non-diagnostic coronary segments and a radiation dose below 1 mSv.

Comparative Study on 16-slice CT Coronary Angiography vs Con-ventional Coronary Angiography―A Report of 38 Cases

The clinical application of 16-slice CT coronary angiography （CTCA） and the impact of plaques differently characterized on assessing coronary artery stenosis were evaluated. Thirty-eight patients with coronary artery disease diagnosed by conventional coronary angiography （CAG） underwent 16-slice CTCA （collimation： 16×0.75 mm; rotation time： 420 msec; kernel： 35f; effective current： 500 mAs; tube voltage： 120 kV）. The interval between CTCA and CAG was within one month. CTCA was evaluated by consensus of two independent experienced radiologists unknowing CAG findings. Original images, maximum intensity projections and multiplanar reconstructions were used to assess coronary artery stenosis. For a determined plaque an attenuation value ≥ 130 HU was considered as calcified, and 〈130 HU noncalcified. The plaques were then classified into significant calcification （extensive calcification）, medium calcification （small isolated calcification） and noncalcification. The diagnostic accuracy of 16-slice CTCA findings as well as to detect ≥50% stenoses caused by plaques was evaluated respectively regarding CAG as the standard of reference. In comparison with CAG findings, the sensitivity, specificity, positive and negative predictive value derived from CTCA for mild stenosis （〈50%） were 72.7%, 38.5%, 50%, 62.5%, respectively; for moderate stenosis （50%-75%） 82.4%, 72.7%, 70%, 84.2%, resepctively; and for severe coronary stenosis （〉75%） 85%, 90.5%, 81%, 92.7% respectively. With the increase of stenoses degree, the value of CTCA was greater. For the classification of the plaque calcification with ≥50% stenosis CTCA attained the sensitivity, specificity, positive and negative predictive value for severe calcificatoin 73.3% 22.2%, 61.1% and 33.3%, respectively; for moderate calcification 70%, 55.6%, 63.6% and 62,5%, respectively; for noncalcification 93.8%, 85.7%, 93.8% and 85.7% respectively. CTCA was restricted in assessing coronary artery stenosis in the presence of calcification, but CTCA value was much improved in assessing non-calcified stenosis. It was concluded that 16-slice CTCA could provide useful information about coronary artery stenosis, especially for severe stenosis （≥ 50%） and non-calcified plaque. Since CTCA is a noninvasive technique, it may be useful in screening coronary artery disease.

Myocardial perfusion imaging and infarct characterization using multidetector cardiac computed tomography

Until recently, computed tomography coronary angiography was restricted to the anatomical assessment of coronary stenosis, whereas the functional significance of coronary lesions remained outside of its scope. Nevertheless, the kinetics of iodinated contrast is similar to gadolinium-diethylenetriamine pentaacetic acid used in contrast-enhanced magnetic resonance imaging, allowing assessment of myocardial perfusion and viability by cardiac computed tomography.

Different therapeutic proportion of patients undergone coronary angiography in the era of development in MSCT

Objective To study the different therapeutic proportion of the patient populations undergone coronary angiography (CAG) in the era of development in multislice spiral computed tomography(MSCT). Methods Two hundred and fifty four consecutive patients(mean age 59.24±10.65) , who underwent CAG at Daxing Hospital from February 2007 through October 2007, were enrolled, 160 patients were male and 94 were female. By evaluating from the coronary angiogram, the patients were not diagnosed to have coronary heart disease(CHD) with less than 50% diameter stenosis of coronary artery; the patients to have CHD with more than or equal to 50% stenosis of coronary artery; the patients were performed the procedure of percutaneous coronary intervention(PCI) with more than or equal to 70% stenosis; the patients were proposed to have coronary aortic bypass graft(CABG) surgery with left main coronary artery lesions or diffuse triple coronary artery lesions. Results In the 254 consecutive patients, 59 patients(23.2%) had not been diagnosed to have CHD; 195(76.8%)to have CHD, of these patients with CHD, 49 patients(19.3%)were not indicated for PCI (including the patients receiving follow-up coronary angiography after stenting), 81(31.9%)had been performed the procedure of stent implantation, 57(22.4%)proposed to have CABG, 8(3.1%)the procedure of PCI had not been successful, or had not been performed because of patients opposing to this therapy. Conclusion Multislice spiral computed tomography can be applied as a non-invasive screening tool to exclude the presence of CHD, to increase the positive proportion of the populations with CHD in all patients receiving coronary angiograhpy, to avoid the use of CAG in a subset of