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.

Perivascular Fat Attenuation Index on Non-Contrast-Enhanced Cardiac Computed Tomography: Comparison with Coronary Computed Tomography Angiography

Objective: Perivascular fat attenuation index (FAI) measurement on non-contrast-enhanced cardiac computed tomography (NCCT) has not been rigorously validated in previous studies. Herein, we compared perivascular FAI values between NCCT and coronary computed tomography angiography (CCTA). We also investigated the variability and reproducibility of perivascular FAI measurement. Methods: A total of 44 patients who underwent NCCT and CCTA were included in this study. For NCCT, perivascular FAI was measured using three threshold settings: from −30 to −190 Hounsfield Units (HU), −20 to −180 HU, and −10 to −170 HU. For CCTA, perivascular FAI was measured using one threshold setting: from −30 to −190 HU. Perivascular FAI measurements by NCCT were compared with those by CCTA using the paired t-test, and correlations were assessed using Pearson’s correlation coefficient. The intra- and inter-observer variabilities for the measurements with NCCT and CCTA were evaluated with the intraclass correlation coefficient. Results: Perivascular FAI measurements with the threshold setting of −30 to −190 HU were significantly lower on NCCT than on CCTA. There were no significant differences between the perivascular FAI measurements at the remaining thresholds on NCCT and those on CCTA. The perivascular FAI at all thresholds on NCCT correlated significantly with those on CCTA. The intra- and inter-observer agreements were excellent for the measurements on NCCT and CCTA. Conclusion: There were significant differences between the perivascular FAI measurements on NCCT and CCTA. However, the differences could be modified by threshold adjustment.

The coronary computed tomography angiogram: from the basics to advanced interpretation

Introduction According to the WHO's World Health Report 2003, 1cardiovascular disease was responsible for 16.7 million deaths annually. As a result, it is now the leading cause of death in developed countries and in many developing countries. Detecting and preventing the progression of coronary artery disease is the target of many pharmaceutical, technological and other scientific programs today. Presently, the main diagnostic tool for evaluating coronary arteries is thc conventional coronary angiogram (CCA).……

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.

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.

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.

Four-year clinical outcome in asymptomatic patients undergoing coronary computed tomography angiography

Background Percutaneous coronary intervention （PCI） is indicated for angina with coronary stenosis. However, PCI for asymptomatic coronary stenosis remains controversial. We prospectively followed a group of patients for four years who underwent coronary computed tomography angiography （CCTA） for major adverse cardiac events （MACE）. We hypothesized that the results of this trial would reliably reflect the natural outcome of the coronary disease. Methods Consecutive patients who underwent CCTA from June 2008 to May 2009 were selected. Those who could not be reached by telephone, had significant angina, had CT images that were not interpretable, or poor kidney and left ventricular （LV） function were excluded. The patients were divided into five groups： group A normal CCTA without stenosis, group B mild stenosis （1%-49%）, group C moderate stenosis （50%-74%）, group D severe stenosis （≥75%） and they were treated with optimal medical therapy （OMT） or PCI. The group E had PCI before the CCTA examination. The patients were then followed for MACE after different treatments. MACE included acute myocardial infarction （MI）, heart failure （HF） and death. Results The patient population consisted of 419 patients. The follow-up time was （51±5） months. The age was （60±31） years. Male made up 67.78% of the population （n=284）. A total of 51 cases of MACE occurred including 25 MI, eight HF and 18 all-cause deaths. There was no MACE in group A. Although MACE occurred in two patients in group B, they were not attributed to cardiac death. We further compared the MACE in groups C-E and no significant difference was found （P 〉0.05）. However, a difference was detected among patients with unstable angina pectods （UAP）, stable angina pectoris （SAP）, re-hospitalization, and cerebrovascular events from groups A-E （P 〈0.05）. The plaque scores were used to predict MACE. The scores progressively increased significantly with lesion severity （P 〈0.05）. Receiver operating curve （ROC） was performed to determine the sensitivity and specificity in predicting MACE. Our scores predicted MI with area of 0.76, predicted HF with area of 0.77, and predicted death with area of 0.70. Conclusions Normal and mild lesions had very few events. With increased stenosis the MACE rate increased progressively. PCI did not significantly reduce the MACE in comparison with OMT in asymptomatic patients. Furthermore, UAP, re-hospitalization, and re-PCI were sianificantlv increased in patients who were treated with PCI.

Calcified plaque: the Achilles' Heel of present computed tomography coronary angiography for the elderly?

Nine percent to 27% of cardiac catheterizations today showed either angiographic normal coronary arteries or minimal atherosclerosis. 1,2 Given the expense of cardiac catheterization and the desire to use this valuable resource for therapeutic rather than diagnostic purpose, there is a strong impetus to develop non-invasive means of accurately detecting significant coronary artery stenosis.……

Coronary arterial bypass graft patency evaluated by multi-detector computed tomography and magnetic resonance imaging

The progression of atherosclerosis of the coronary artery does not stop after coronary arterial bypass grafting (CABG) surgery.……

The Different Patterns of Coronary Artery Calcification in Acute and Chronic Coronary Syndromes Determined by Electron Beam Computed Tomography

Objectives To compare the different patterns of coronary artery calcification (CAC) in acute and chronic coronary syndromes utilizing electron beam computed tomography. Background Pathologic, angiographic, and intracoronary ultrasound studies revealed sharp differences in the plaque morphology between patients with acute versus chronic coronary syndromes. Whether there are different patterns of coronary artery calcification in patients with stable angina pectoris (SAP) and in those with unstable angina pectoris (UAP) or acute myocardial infarction (AMI), however, remains unclear. Methods Two hundred and sixty - four patients, including 67 with SAP, 94 with UAP and 103 with AMI were studied with electron beam computed tomography for analysis of coronary artery calcification and with selective coronary angiography for determination of atherosclerotic lesions. CAC prevalence and calcium score were compared among three groups, and relation of CAC to the severity of atherosclerotic disease in the SAP and UAP patients was separately analyzed. Results Prevalence of CAC was 100 % in the SAP patients, significantly higher than the 87. 23 % in UAP patients and 86. 41 % among the patients with AMI ( P < 0. 05) . More patients and arteries in the SAP group had severe forms of calcium than those in the UAP and AMI group ( P < 0. 01), and the mean LN [CS + 1] (natural logarithm transformation of calcium score) of the SAP patients was much greater than that of the UAP and AMI patients (P < 0.001). The distribution of vessels with various CAC by luminal stenosis was different between SAP and UAP patients. The average CAC extent of the infarct - related arteries was less severe than that of the noninfarct - related arteries. Conclusions U-tilizing electron beam computed tomography, we demonstrated that there exist different patterns of coronary artery calcification in patients with acute versus chronic coronary syndromes, which may provide insight into the differences observed in the clinical and pathologic development between these two types of coronary artery disease.

Double-chambered left ventricle with a thrombus in an asymptomatic patient:A case report

BACKGROUND Double-chambered left ventricle(DCLV)is an extremely rare congenital disease in which the left ventricle(LV)is divided by abnormal muscle tissue.Due to its rarity,there is a lack of data on the disease,including its diagnosis,treatment,and prognosis.Accordingly,we report a case in which DCLV was diagnosed and followed up.CASE SUMMARY A 45-year-old man presented to our hospital due to abnormal findings on an electrocardiogram recorded during a health check.He had no specific cardiac symptoms,comorbidities or relevant past medical history.Echocardiography revealed that the LV was divided into two by muscle fibers.There were no findings of ischemia on coronary angiography and coronary computed tomography angiography performed to exclude differential diagnoses.After comprehensive analysis of the images,DCLV was diagnosed.As it seemed to be asymptomatic DCLV,we decided the patient was to be observed without administering any medication.However,follow-up echocardiography revealed a thrombus in the accessory chamber(AC).Anticoagulant medication was initiated,the thrombus resolved,and the patient is currently undergoing follow-up without any specific symptoms.CONCLUSION Asymptomatic,uncomplicated DCLV was diagnosed through multimodal imaging;however,a thrombus in the AC occurred during the follow-up.The findings highlight that multimodal imaging is essential in diagnosing DCLV,and that anticoagulation is important in its management.

Use of coronary CT angiography in the diagnosis of patients with suspected coronary artery disease： findings and clinical indications

Objective To investigate the clinical applications of coronary CT angiography in patients with suspected coronary artery disease and identify factors that affect CT findings. Methods Medical records of patients suspected of coronary artery disease over a period of 12 months from a tertiary teaching hospital were retrospectively reviewed. Patient age, sex （male/female）, duration of symptoms and abnormal rates of coronary CT angiography scans were analysed to investigate the relationship among these parameters. The patients by age were characterized into five groups： under 36 years, 36-45 years, 46-55 years, 56455 years and more than 66 years, respectively; while the duration of symptoms was also classified into five groups： less than one week, one week to one month, one to three months, three to six months and more than six months. Results Of the 880 patient records reviewed, 800 met the above study criteria. Five hundred and forty nine patients demonstrated abnormal CT findings （68.6%）. There was no significant difference in the percentage of abnormal CT findings based on patient sex and the duration of symptoms （P = 0.14）. The abnormal rates of coronary CT angiography, however, increased significantly with increasing age （P 〈 0.001）; with patients over 65 years of age 2.5 times more likely to have an abnormal CT scan relative to a patient under 45 years. A significant difference was found between abnormal coronary CT angiography and the duration of symptoms （P = 0.012）. Conclusions Our results indicate coronary CT angiography findings are significantly related to the patient age group and duration of symptoms. Clinical referral for coronary CT angiography of patients with suspected coronary artery disease needs to be justified with regard to the judicious use of this imaging modality.

Radiation dose measurements in coronary CT angiography

Coronary computed tomography(CT)angiography has been recognized as the most rapidly developed imaging technique in the diagnosis of coronary artery disease due to the emergence and technological advances in multislice CT scanners.Coronary CT angiography has been confirmed to demonstrate high diagnostic and predictive value in coronary artery disease when compared to invasive coronary angiography.However,it suffers from high radiation dose which raises concerns in the medical field.Various dose-reduction strategies have been proposed with effective outcomes having been achieved to reduce radiation exposure to patients.This article provides an introduction and overview of the series of articles that will focus on each particular topic related to coronary CT angiography.

Stent visualization methods to guide percutaneous coronary interventions and assess long-term patency

Evaluation of acute percutaneous coronary intervention(PCI)results and longterm follow-up remains challenging with ongoing stent designs.Several imaging tools have been developed to assess native vessel atherosclerosis and stent expansion,improving overall PCI results and reducing adverse cardiac events.Quantitative coronary analysis has played a crucial role in quantifying the extent of coronary artery disease and stent results.Digital stent enhancement methods have been well validated and improved stent strut visualization.Intravascular imaging remains the gold standard in PCI guidance but adds costs and time to the procedure.With a recent shift towards non-invasive imaging assessment and coronary computed tomography angiography imaging have shown promising results.We hereby review novel stent visualization techniques used to guide PCI and assess stent patency in the modern PCI era.

Highly sensitive troponin I assay in the diagnosis of coronary artery disease in patients with suspected stable angina

BACKGROUND Evaluation of suspected stable angina patients with probable coronary artery disease(CAD)in the community is challenging.In the United Kingdom,patients with suspected stable angina are referred by community physicians to be assessed by specialists within the hospital system in rapid access chest pain clinics(RACPC).The role of a highly sensitive troponin I(uscTnI)assay in the diagnosis of suspected CAD in a RACPC in a“real-life”setting in a non-academic hospital has not been explored.AIM To examine the diagnostic value of uscTnI(detection limit 0.12 ng/L,upper reference range 8.15 ng/L,and detected uscTnI in 96.8%of the reference population),in the evaluation of stable CAD in a non-selected patient group,with several co-morbidities,who presented to the RACPC.METHODS One hundred and seventy two RACPC patients were assigned to either functional or anatomical testing according to the hospital protocol.RESULTS The investigations offered to patients were exercise tolerance test 7.6%,24 h ECG 1.2%,Echocardiogram 14.5%,stress echocardiogram 8.1%,coronary computed tomography angiography(CCTA)12.8%,coronary angiogram 13.4%,17.4%were diagnosed with non-cardiac chest pain,3.5%treated as stable angina,8.2%reviewed by cardiologists,electronic medical records were not available in 10.4%.Receiver operating characteristic curves for CAD used uscTnI values measured in patients who underwent functional testing,angiogram or CCTA.Values>0.52 ng/L showed 100%sensitivity and at>11.6 ng/L showed 100%specificity.In the range>0.52-11.6 ng/L,uscTnI may not have the same diagnostic potential.In patients assigned to coronary angiogram higher concentrations of uscTnI was associated with severe CAD.Low levels of uscTnI and low pre-test probability of CAD(QRISK3)may decrease patient numbers assigned to CCTA.CONCLUSION The uscTnI diagnostic cut-off values in a RACPC will depend on patient population and their presenting co-morbidity.In the presence of clinical comorbidities and previous CAD the uscTnI needs to be used in conjunction with clinical assessment.

Diagnostic Yield of Non-Invasive Testing in Patients with Anomalous Aortic Origin of Coronary Arteries:A Multicentric Experience

Background:Anomalous aortic origin of a coronary artery(AAOCA)is a congenital heart disease with a 0.3%−0.5%prevalence.Diagnosis is challenging due to nonspecific clinical presentation.Risk stratification and treatment are currently based on expert consensus and single-center case series.Methods:Demographical and clinical data of AAOCA patients from 17 tertiary-care centers were analyzed.Diagnostic imaging studies(Bidimensional echocardiography,coronary computed tomography angiography[CCTA]were collected.Clinical correlations with anomalous coronary course and origin were evaluated.Results:Data from 239 patients(42%males,mean age 15 y)affected by AAOCA were collected;154 had AAOCA involving the right coronary artery(AAORCA),62 the left(AAOLCA),23 other anomalies.211(88%)presented with an inter-arterial course.Basal electrocardiogram(ECG)was abnormal in 37(16%).AAOCA was detected by transthoracic echocardiography and CCTA in 53%and 92%of patients,respectively.Half of the patients reported cardiac symptoms(119/239;50%),mostly during exercise in 121/178(68%).An ischemic response was demonstrated in 37/106(35%)and 16/31(52%)of patients undergoing ECG stress test and stress-rest single positron emission cardiac tomography.Compared with AAORCA,patients with AAOLCA presented more frequently with syncope(18%vs.5%,P=0.002),in particular when associated with inter-arterial course(22%vs.5%,P<0.001).Conclusion:Diagnosis of AAOCA is a clinical challenge due to nonspecific clinical presentations and low sensitivity of first-line cardiac screening exams.Syncope seems to be strictly correlated to AAOLCA with inter-arterial course.

Plaque imaging with CT coronary angiography:Effect of intra-vascular attenuation on plaque type classification

AIM: To assess the attenuation of non-calcified atherosclerotic coronary artery plaques with computed tomography coronary angiography (CTCA). METHODS: Four hundred consecutive patients underwent CTCA (Group 1: 200 patients, Sensation 64 Cardiac, Siemens; Group 2: 200 patients, VCT GE Healthcare, with either Iomeprol 400 or Iodixanol 320, respectively) for suspected coronary artery disease (CAD). CTCA was performed using standard protocols. Image quality (score 0-3), plaque (within the accessible non-calcified component of each non-calcified/mixed plaque) and coronary lumen attenuation were measured. Data were compared on a per-segment/per-plaque basis. Plaques were classified as fibrous vs lipid rich based on different attenuation thresholds. A P < 0.05 was considered significant. RESULTS: In 468 atherosclerotic plaques in Group 1 and 644 in Group 2, average image quality was 2.96 ± 0.19 in Group 1 and 2.93 ± 0.25 in Group 2 (P ≥ 0.05). Coronary lumen attenuation was 367 ± 85 Hounsfield units (HU) in Group 1 and 327 ± 73 HU in Group 2 (P < 0.05); non-calcified plaque attenuation was 48 ± 23 HU in Group 1 and 39 ± 21 HU in Group 2 (P < 0.05). Overall signal to noise ratio was 15.6 ± 4.7 in Group 1 and 21.2 ± 7.7 in Group 2 (P < 0.01). CONCLUSION: Higher intra-vascular attenuation modifies significantly the attenuation of non-calcified coronary plaques. This results in a more difficult characterization between lipid rich vs fibrous type.

Effects of different statins application methods on plaques in patients with coronary atherosclerosis

BACKGROUND Discontinued application of statins may be related to adverse cardiovascular events.However,it is unclear whether different statins administration methods have effects on coronary artery plaques.AIM To evaluate the effects of different statins application methods on plaques in patients with coronary atherosclerosis.METHODS A total of 100 patients diagnosed with atherosclerotic plaque by coronary artery computed tomography were continuously selected and divided into three groups according to different statins administration methods(discontinued application group,n=32;intermittent application group,n=39;sustained application group,n=29).The effects of the different statins application methods on coronary atherosclerotic plaque were assessed.RESULTS The volume change and rate of change of the most severe plaques were significantly reduced in the sustained application group(P≤0.001).The volume change of the most severe plaques correlated positively with low-density lipoprotein(LDL-C)levels only in the sustained application group(R=0.362,P=0.013).There were no changes in plaques or LDL-C levels in the intermittent and discontinued application groups.CONCLUSION Continuous application of statins is effective for controlling plaque progression,whereas discontinued or intermittent administration of statins is not conducive to controlling plaques.Only with continuous statins administration can a reduction in LDL-C levels result in plaque volume shrinkage.

Diagnostic value of18F-FDG PET in the assessment of myocardial viability in coronary artery disease：A comparative study with99mTc SPECT and echocar-diography

ObjectiveTo investigate the diagnostic value of 18F-fluorodeoxyglucose positron emission tomography （18F-FDG PET） in the as-sessment of myocardial viability in patients with known coronary artery disease （CAD） when compared to99mTc single photon emission computed tomography （SPECT） and echocardiography, with invasive coronary angiography as the gold standard.MethodsThirty patients with diagnosed CAD met the selection criteria, with 10 of them （9 men, mean age 59.5 ± 10.5 years） undergoing all of these imaging proce-dures consisting of SPECT and PET, echocardiography and invasive angiography. Diagnostic sensitivity of these less invasive modalities for detection of myocardial viability was compared to invasive coronary angiography. Inter- and intra-observer agreement was assessed for di-agnostic performance of SPECT and PET.ResultsOf all patients with proven CAD, 50% had triple vessel disease. Diagnostic sensitivity of SPECT, PET and echocardiography was 90%, 100% and 80% at patient-based assessment, respectively. Excellent agreement was achieved between inter-observer and intra-observer agreement of the diagnostic value of SPECT and PET in myocardial viability （k= 0.9）. Conclusion18F-FDG PET has high diagnostic value in the assessment of myocardial viability in patients with known CAD when com-pared to SPECT and echocardiography. Further studies based on a large cohort with incorporation of18F-FDG PET into patient management are warranted.

Molecular imaging of plaques in coronary arteries with PET and SPECT

Coronary artery disease remains a major cause of mortality. Presence of atherosclerotic plaques in the coronary artery is responsible for lu-men stenosis which is often used as an indicator for determining the severity of coronary artery disease. However, the degree of coronary lumen stenosis is not often related to compromising myocardial blood flow, as most of the cardiac events that are caused by atherosclerotic plaques are the result of vulnerable plaques which are prone to rupture. Thus, identification of vulnerable plaques in coronary arteries has become increas-ingly important to assist identify patients with high cardiovascular risks. Molecular imaging with use of positron emission tomography （PET） and single photon emission computed tomography （SPECT） has fulfilled this goal by providing functional information about plaque activity which enables accurate assessment of plaque stability. This review article provides an overview of diagnostic applications of molecular imaging tech-niques in the detection of plaques in coronary arteries with PET and SPECT. New radiopharmaceuticals used in the molecular imaging of coro-nary plaques and diagnostic applications of integrated PET/CT and PET/MRI in coronary plaques are also discussed.