Michael Poon

Assessment of isotropic calcium using 0.5-mm reconstructions from 320-row CT data sets identifies more patients with non-zero Agatston score and more subclinical atherosclerosis than standard 3.0-mm coronary artery calcium scan and CT angiography

BACKGROUND The presence of calcified plaque in coronary arteries can be quantified by using 0.5-mm isotropic reconstructions from 320-row CT without increased radiation dose. Little is known about reclassification of patients with non-zero Agatston scores and quantitative measures of calcified plaque using 0.5-mm reconstructions. OBJECTIVE The aim was to compare proportions of zero vs. non-zero Agatston scores (subclinical atherosclerosis) in 0.5-mm isotropic reconstructions vs. standard 3.0-mm and CT angiography (CTA) scans on 320-row CT. METHODS Prospectively, we quantified calcified plaque in coronary arteries in 104 patients by using non-contrast-enhanced scans with 0.5 and 3.0 mm. Coronary calcium assessment was determined by 2 observers. Clinically indicated CTA was also performed; coronary calcium assessment findings were compared with CTA. Ranked Wilcoxon test and χ2 test were performed for comparison. Reproducibility for proportion of zero vs non-zero was assessed by κ statistics. RESULTS Median Agatston score (41.9 [interquartile range (IQR), 3.7-213.6] vs. 5.2 [IQR, 0.0-128.5]), calcium volume (53.6 mm3 [IQR, 8.1-202.3] vs. 5.1 mm(3) [IQR, 0.0-96.8],), and lesion number (10.0 [IQR, 3.5-18.5] vs. 1.0 [IQR, 0.0-6.0]) were significantly higher on 0.5-mm reconstruction (P < .0001) than on 3.0-mm reconstruction. More patients with subclinical atherosclerosis were detected on 0.5 mm than on 3.0 mm and CTA scans (76.9% vs. 53.8% vs. 54.8%; P < .0001). The κ values for inter-rater agreement were 0.94 and 0.52 on 3.0- and 0.5-mm data sets, respectively. However, when Agatston scores < 10 were excluded from analysis, the κ value rose to 0.83. CONCLUSION Isotropic 0.5-mm reconstruction detected 23.1% and 22.1% more patients with subclinical atherosclerosis than standard 3.0-mm scans and CTA, which may be more sensitive for the detection of subclinical atherosclerosis; its potential clinical utility needs to be validated in large, prospective studies.

Utilization of coronary computed tomography angiography for exclusion of coronary artery disease in ED patients with low- to intermediate-risk chest pain: a 1-year experience ☆

OBJECTIVE We describe our preliminary experience with coronary computed tomography angiography (CCTA) in emergency department (ED) patients with low- to intermediate-risk chest pain. METHODS A convenience cohort of patients with low- to intermediate-risk acute chest pain presenting to a suburban ED in 2009 were prospectively enrolled if the attending physician ordered a CCTA for possible coronary artery disease. Demographic and clinician data were entered into structured data collection sheets required before any imaging. The results of CCTA were classified as normal, nonobstructive (1%-50% stenosis), and obstructive (>50% stenosis). Outcomes included hospital admission and death within a 6-month follow-up period. RESULTS In 2009, 507 patients with ED chest pain had a CCTA while in the ED. The median (interquartile range) age was 54 (47-62) years; 51.5% were female. Thrombolysis in myocardial infarction risk scores were 0 (42.6%), 1 (42.2%), 2 (11.8%), 3 (2.4%), and 4 (1.0%). The results of CCTA were normal (n = 363), nonobstructive (n = 123), and obstructive (n = 21). Admission rates by CCTA results were obstructive (90.5%), nonobstructive (4.9%), and normal (3.0%). None of the patients with normal or nonobstructive CCTA died within the 6-month follow-up period (0%; 95% confidence interval, 0-0.9%). CONCLUSIONS Many ED patients with low- to intermediate-risk chest pain have a normal or nonobstructive CCTA and may be safely discharged from the ED without any associated mortality within the following 6 months.

Computer-aided analysis of 64-slice coronary computed tomography angiography: a comparison with manual interpretation.

Coronary computed tomography angiography (CCTA) is increasingly used for the assessment of coronary heart disease (CHD) in symptomatic patients. Software applications have recently been developed to facilitate efficient and accurate analysis of CCTA. This study aims to evaluate the clinical application of computer-aided diagnosis (CAD) software for the detection of significant coronary stenosis on CCTA in populations with low (8%), moderate (13%), and high (27%) CHD prevalence. A total of 341 consecutive patients underwent 64-slice CCTA at 3 clinical sites in the United States. CAD software performed automatic detection of significant coronary lesions (>50% stenosis). CAD results were then compared to the consensus manual interpretation of 2 imaging experts. Data analysis was conducted for each patient and segment. The CAD had 100% sensitivity per patient across all 3 clinical sites. Specificity in the low, moderate, and high CHD prevalence populations was 64%, 41%, and 38%, respectively. The negative predictive value at the 3 clinical sites was 100%. The positive predictive value was 22%, 21%, and 38% for the low, moderate, and high CHD prevalence populations, respectively. This study demonstrates the utility of CAD software in 3 distinct clinical settings. In a low-prevalence population, such as seen in the emergency department, CAD can be used as a Computer-Aided Simple Triage tool to assist in diagnostic delineation of acute chest pain. In a higher prevalence population, CAD software is useful as an adjunct for both the experienced and inexperienced reader.

Azygous Continuation of Inferior Vena Cava

![Figure][1] A 70-year-old man presented for typical atrial flutter ablation. Right femoral venous access was obtained but there was difficulty in catheter advancement into the right atrium and the procedure was abandoned. The patient was sent for a cardiac computed tomographic angiography.

Real-world clinical utility and impact on clinical decision-making of coronary computed tomography angiography-derived fractional flow reserve: lessons from the ADVANCE Registry

Abstract Aims Non-invasive assessment of stable chest pain patients is a critical determinant of resource utilization and clinical outcomes. Increasingly coronary computed tomography angiography (CCTA) with selective CCTA-derived fractional flow reserve (FFRCT) is being used. The ADVANCE Registry, is a large prospective examination of using a CCTA and FFRCT diagnostic pathway in real-world settings, with the aim of determining the impact of this pathway on decision-making, downstream invasive coronary angiography (ICA), revascularization, and major adverse cardiovascular events (MACE). Methods and results A total of 5083 patients with symptoms concerning for coronary artery disease (CAD) and atherosclerosis on CCTA were enrolled at 38 international sites from 15 July 2015 to 20 October 2017. Demographics, symptom status, CCTA and FFRCT findings, treatment plans, and 90 days outcomes were recorded. The primary endpoint of reclassification between core lab CCTA alone and CCTA plus FFRCT-based management plans occurred in 66.9% [confidence interval (CI): 64.8–67.6] of patients. Non-obstructive coronary disease was significantly lower in ICA patients with FFRCT ≤0.80 (14.4%) compared to patients with FFRCT >0.80 (43.8%, odds ratio 0.19, CI: 0.15–0.25, P < 0.001). In total, 72.3% of subjects undergoing ICA with FFRCT ≤0.80 were revascularized. No death/myocardial infarction (MI) occurred within 90 days in patients with FFRCT >0.80 (n = 1529), whereas 19 (0.6%) MACE [hazard ratio (HR) 19.75, CI: 1.19–326, P = 0.0008] and 14 (0.3%) death/MI (HR 14.68, CI 0.88–246, P = 0.039) occurred in subjects with an FFRCT ≤0.80. Conclusions In a large international multicentre population, FFRCT modified treatment recommendation in two-thirds of subjects as compared to CCTA alone, was associated with less negative ICA, predicted revascularization, and identified subjects at low risk of adverse events through 90 days.

Coronary CT angiography reduces unnecessary admissions and allows safe discharge of emergency department patients with low-to-intermediate risk chest pain

Commentary on: Litt HI, Gatsonis C, Snyder B, et al. CT angiography for safe discharge of patients with possible acute coronary syndromes. N Engl J Med 2012;366:1393–403.[OpenUrl][1][CrossRef][2][PubMed][3][Web of Science][4] Chest pain is the second-most common reason for visiting the emergency department (ED). Due to diagnostic uncertainty and medicolegal concerns, many such patients are admitted to undergo diagnostic evaluation to exclude acute coronary syndromes (ACS). The availability of a safe, rapid, non-invasive and highly accurate diagnostic test to exclude ACS has remained a holy grail in the ED. A total of 1370 low-to-intermediate risk adult patients presenting to one of five EDs in the USA with chest pain and suspected ACS were randomised to coronary CT angiography (CCTA) or to standard care. Patients with … [1]: {openurl}?query=rft.jtitle%253DNew%2BEngland%2BJournal%2Bof%2BMedicine%26rft.stitle%253DNEJM%26rft.issn%253D0028-4793%26rft.aulast%253DLitt%26rft.auinit1%253DH.%2BI.%26rft.volume%253D366%26rft.issue%253D15%26rft.spage%253D1393%26rft.epage%253D1403%26rft.atitle%253DCT%2Bangiography%2Bfor%2Bsafe%2Bdischarge%2Bof%2Bpatients%2Bwith%2Bpossible%2Bacute%2Bcoronary%2Bsyndromes.%26rft_id%253Dinfo%253Adoi%252F10.1056%252FNEJMoa1201163%26rft_id%253Dinfo%253Apmid%252F22449295%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [2]: /lookup/external-ref?access_num=10.1056/NEJMoa1201163&link_type=DOI [3]: /lookup/external-ref?access_num=22449295&link_type=MED&atom=%2Febmed%2F18%2F2%2F64.atom [4]: /lookup/external-ref?access_num=000302608600003&link_type=ISI

Validity of Coronary Artery Disease Consortium Models for Predicting Obstructive Coronary Artery Disease & Cardiovascular Events in Patients with Acute Chest Pain Considered for Coronary Computed Tomographic Angiography

Although the majority of acute chest pain patients are diagnosed with noncardiac chest pain after noninvasive testing, identifying these low-risk patients before testing is challenging. The objective of this study was to validate the coronary artery disease (CAD) consortium models for predicting obstructive CAD and 30-day major adverse cardiovascular events (MACE) in acute chest pain patients considered for coronary computed tomography angiogram, as well as to determine the pretest probability threshold that identifies low-risk patients with <1% MACE. We studied 1,981 patients with no known CAD and negative initial troponin and electrocardiogram. We evaluated CAD consortium models (basic: age, sex, and chest pain type; clinical: basic + diabetes, hypertension, dyslipidemia, and smoking; and clinical + coronary calcium score [CAC] models) for prediction of obstructive CAD (≥50% stenosis on coronary CT angiogram) and 30-day MACE (Acute Myocardial Infarction, revascularization, and mortality). The C-statistic for predicting obstructive CAD was 0.77 (95% confidence interval [CI] 0.73 to 0.77) for the basic, 0.80 (95% CI 0.77 to 0.80) for the clinical, and 0.88 (95% CI 0.85 to 0.88) for the clinical + CAC models. The C-statistic for predicting 30-day MACE was 0.82 (95% CI 0.77 to 0.87) for the basic, 0.84 (95% CI 0.79 to 0.88) for the clinical, and 0.87 (95% CI 0.83 to 0.91) for the clinical + CAC models. In 47.3% of patients for whom the clinical model predicted ≤5% probability for obstructive CAD, the observed 30-day MACE was 0.53% (95% CI 0.07% to 0.999%); in the 66.9% of patients for whom the clinical + CAC model predicted ≤5% probability, the 30-day MACE was 0.75% (95% CI 0.29% to 1.22%). We propose a chest pain evaluation algorithm based on these models that classify 63.3% of patients as low risk with 0.56% (95% CI 0.15% to 0.97%) 30-day MACE. In conclusion, CAD consortium models have excellent diagnostic and prognostic value for acute chest pain patients and can safely identify a significant proportion of low-risk patients by achieving <1% missed 30-day MACE.

Coronary Artery Disease Evaluation Using Cardiac CTA

The application of cardiovascular CT imaging toward the detection, characterization, and prognostication of coronary artery disease (CAD) is one of the most rapidly evolving and exciting aspects of cardiovascular medicine. Coronary computed tomographic angiography (CCTA) has revolutionized the diagnosis and management of coronary artery disease by providing new methods for noninvasive imaging of coronary arteries. Coronary arterial calcification of plaques, plaque progression, stenosis characterization, plaque analysis, and appropriate use criteria will be presented below.

The Role of Cardiac Magnetic Resonance Imaging in Cardiology Consultation

Cardiovascular magnetic resonance imaging (CMR) has emerged as a powerful, multipurpose, noninvasive imaging modality of great value to cardiac consultants who are asked increasingly to evaluate increasingly complex cases of cardiac anatomy and pathophysiology. CMR, unlike other imaging modalities that require ionizing radiation, is extremely safe and suited for the evaluation of both congenital and acquired cardiac diseases. CMR is the gold standard for the evaluation of global systolic function, abnormal tissue characteristics, and myocardial viability. This chapter will review key fundamental principles in MR physics that form the basis of MR imaging followed by a brief discussion of image acquisition and signal processing that are unique for CMR. Basic CMR pulse sequences and common clinical applications of these sequences will be discussed including the use of flow/velocity encoding sequences in the quantitative analysis of flow and myocardial stress imaging. The chapter will also touch on the common roles of CMR in the assessment of restrictive, dilated, and hypertrophic cardiomyopathies, valvular heart disease, congestive heart failure, myocarditis, cardiac neoplasms, pericardial disease, and congenital heart disease. Technical and patient safety issues will also be reviewed. To date, CMR remains a relatively time-consuming and technically difficult imaging modality and is not commonly available. Future improvement in hardware and software as well as simplifying image post-processing will improve the availability of CMR and allow it to be performed on even more challenging patients.

The Role of Coronary Computed Tomography Angiography in Cardiology Consultation

Cardiac computed tomography (CCT) has rapidly become an integral part of noninvasive diagnostic cardiovascular imaging. Coronary artery calcium scoring using either electronic beam computed tomography (CT) or multidetector row CT is useful in the reclassification of coronary artery disease (CAD) risk when combined with the clinical CAD risk scoring in asymptomatic individuals. Coronary computed tomography angiography (CCTA) has a very high negative predictive value for ruling out the presence of significant obstructive CAD in symptomatic patients with either chronic or acute chest pain. Newer generation of scanners and software algorithms allows CCT studies to be performed easily in more patients with much lower effective radiation exposure. CCTA allows infinite viewing angle of the heart and its associated vascular structure retrospectively and is thus an invaluable and unique diagnostic tool for the assessment of cardiac structure and morphology prior to invasive procedures. Moreover, CCT aids in the diagnosis and management of patients with complex congenital heart disease and suspected coronary anomalies. It often obviates the need for invasive coronary angiography prior to noncoronary cardiac surgery and early post-coronary artery bypass grafting or coronary stenting for evaluation of the patency of native, grafted, or stented coronary vessels. Novel research applications of CCTA in the assessment of stress and rest myocardial perfusion, cardiac viability, and atherosclerotic plaque imaging may further open the window of opportunity for CCT to be the ultimate multipurpose diagnostic imaging modality of the future.