In coronary computed tomographic angiography (CTA), low attenuation of coronary atherosclerotic plaque is associated with lipid-rich plaques. However, an overlap in Hounsfield units (HU) between ...fibrous and lipid-rich plaque as well as an influence of luminal enhancement on plaque attenuation was observed and may limit accurate detection of lipid-rich plaques by CTA. We sought to determine whether the quantitative histogram analysis improves accuracy of the detection of lipid-core plaque (LCP) in ex vivo hearts by validation against histological analysis.
Human donor hearts were imaged with a 64-slice computed tomographic scanner using a standard coronary CTA protocol, optical coherence tomography (OCT), a histological analysis. Lipid-core plaque was defined in the histological analysis as any fibroatheroma with a lipid/necrotic core diameter of greater than 200 μm and a circumference greater than 60 degrees as well as a cap thickness of less than 450 μm. In OCT, lipid-rich plaque was determined as a signal-poor region with diffuse borders in 2 quadrants or more. In CTA, the boundaries of the noncalcified plaque were manually traced. The absolute and relative areas of low attenuation plaque based on pixels with less than 30, less than 60, and less than 90 HU were calculated using quantitative histogram analysis.
From 5 hearts, a total of 446 cross sections were coregistered between CTA and the histological analysis. Overall, 55 LCPs (12%) were identified by the histological analysis. In CTA, the absolute and relative areas of low attenuation plaque less than 30, less than 60, and less than 90 HU were 0.14 (0.31) mm2 (4.22% 9.02%), 0.69 (0.95) mm2 (18.28% 21.22%), and 1.35 (1.54) mm2 (35.65% 32.07%), respectively. The low attenuation plaque area correlated significantly with histological lipid content (lipid/necrotic core size in square millimeter and a portion of lipid/necrotic core on the entire plaque) at all thresholds but was the strongest at less than 60 HU (r = 0.53 and r = 0.48 for the absolute and relative areas, respectively). Using a threshold of 1.0 mm2 or greater, the absolute plaque area of less than 60 HU in CTA yielded 69% sensitivity and 80% specificity to detect LCP, whereas sensitivity and specificity were 73% and 71% for using 25.0% or higher relative area less than 60 HU. The discriminatory ability of CTA for LCP was similar between the absolute and relative areas (the area under the curve, 0.744 versus 0.722; P = 0.37). Notably, the association of the low attenuation plaque area in CTA with LCP was not altered by the luminal enhancement for the relative (P = 0.48) but for the absolute measurement (P = 0.03). Similar results were achieved when validated against lipid-rich plaque by OCT in a subset of 285 cross sections.
In ex vivo conditions, the relative area of coronary atherosclerotic plaque less than 60 HU in CTA as derived from quantitative histogram analysis has good accuracy to detect LCP as compared with a histological analysis independent of differences in luminal contrast enhancement.
Background
Obesity is associated with altered atrial electrophysiology and a prominent risk factor for atrial fibrillation. Body mass index, the most widely used adiposity measure, has been related ...to atrial electrical remodeling. We tested the hypothesis that pericardial fat is independently associated with electrocardiographic measures of atrial conduction.
Methods and Results
We performed a cross‐sectional analysis of 1946 Framingham Heart Study participants (45% women) to determine the relation between pericardial fat and atrial conduction as measured by P wave indices (PWI): PR interval, P wave duration (P‐duration), P wave amplitude (P‐amplitude), P wave area (P‐area), and P wave terminal force (P‐terminal). We performed sex‐stratified linear regression analyses adjusted for relevant clinical variables and ectopic fat depots. Each 1‐SD increase in pericardial fat was significantly associated with PR interval (β=1.7 ms, P=0.049), P‐duration (β=2.3 ms, P<0.001), and P‐terminal (β=297 μV·ms, P<0.001) among women; and P‐duration (β=1.2 ms, P=0.002), P‐amplitude (β=−2.5 μV, P<0. 001), and P‐terminal (β=160 μV·ms, P=0.002) among men. Among both sexes, pericardial fat was significantly associated with P‐duration in analyses additionally adjusting for visceral fat or intrathoracic fat; a similar but non‐significant trend existed with P‐terminal. Among women, pericardial fat was significantly associated with P wave area after adjustment for visceral and intrathoracic fat.
Conclusions
Pericardial fat is associated with atrial conduction as quantified by PWI, even with adjustment for extracardiac fat depots. Further studies are warranted to identify the mechanisms through which pericardial fat may modify atrial electrophysiology and promote subsequent risk for arrhythmogenesis.
Objectives
The size of the heart may predict major cardiovascular events (MACE) in patients with stable chest pain. We aimed to evaluate the prognostic value of 3D whole heart volume (WHV) derived ...from non-contrast cardiac computed tomography (CT).
Methods
Among participants randomized to the CT arm of the Prospective Multicenter Imaging Study for Evaluation of Chest Pain (PROMISE), we used deep learning to extract WHV, defined as the volume of the pericardial sac. We compared the WHV across categories of cardiovascular risk factors and coronary artery disease (CAD) characteristics and determined the association of WHV with MACE (all-cause death, myocardial infarction, unstable angina; median follow-up: 26 months).
Results
In the 3798 included patients (60.5 ± 8.2 years; 51.5% women), the WHV was 351.9 ± 57.6 cm
3
/m
2
. We found smaller WHV in no- or non-obstructive CAD, women, people with diabetes, sedentary lifestyle, and metabolic syndrome. Larger WHV was found in obstructive CAD, men, and increased atherosclerosis cardiovascular disease (ASCVD) risk score (
p
< 0.05). In a time-to-event analysis, small WHV was associated with over 4.4-fold risk of MACE (HR (per one standard deviation) = 0.221; 95% CI: 0.068–0.721;
p
= 0.012) independent of ASCVD risk score and CT-derived CAD characteristics. In patients with non-obstructive CAD, but not in those with no- or obstructive CAD, WHV increased the discriminatory capacity of ASCVD and CT-derived CAD characteristics significantly.
Conclusions
Small WHV may represent a novel imaging marker of MACE in stable chest pain. In particular, WHV may improve risk stratification in patients with non-obstructive CAD, a cohort with an unmet need for better risk stratification.
Key Points
• Heart volume is easily assessable from non-contrast cardiac computed tomography.
• Small heart volume may be an imaging marker of major adverse cardiac events independent and incremental to traditional cardiovascular risk factors and established CT measures of CAD.
• Heart volume may improve cardiovascular risk stratification in patients with non-obstructive CAD.
Long-term exposure to traffic and particulate matter air pollution is associated with a higher risk of cardiovascular disease, potentially via atherosclerosis promotion. Prior research on ...associations of traffic and particulate matter with coronary artery calcium Agatston score (CAC), an atherosclerosis correlate, has yielded inconsistent findings. Given this background, we assessed whether residential proximity to major roadway or fine particulate matter were associated with CAC in a Northeastern US study.
We measured CAC ≤2 times from 2002 to 2005 and 2008 to 2011 among Framingham Offspring or Third-Generation Cohort participants. We assessed associations of residential distance to major roadway and residential fine particulate matter (2003 average; spatiotemporal model) with detectable CAC, using generalized estimating equation regression. We used linear mixed effects models to assess associations with loge(CAC). We also assessed associations with CAC progression. Models were adjusted for demographic variables, socioeconomic position markers, and time. Among 3399 participants, 51% had CAC measured twice. CAC was detectable in 47% of observations. At first scan, mean age was 52.2 years (standard deviation 11.7); 51% male. There were no consistent associations with detectable CAC, continuous CAC, or CAC progression. We observed heterogeneous associations of distance to major roadway with odds of detectable CAC by hypertensive status; interpretation of these findings is questionable.
Our findings add to prior work and support evidence against strong associations of traffic or fine particulate matter with the presence, extent, or progression of CAC in a region with relatively low levels of and little variation in fine particulate matter.
Context:
The relationship between sex steroids and atherosclerosis is poorly understood.
Objective:
To describe the association of serum total T (TT), calculated free T (cFT), estrone (E1), estradiol ...(E2), and SHBG to vascular calcification in adult men.
Design:
Observational study (Framingham Heart Study). Analyses are cross-sectional. TT, E1, and E2 were measured by liquid chromatography-tandem mass spectrometry, and SHBG by immunofluorometric assay. Estimates of association were obtained by Tobit regression, which acknowledges the influence of floor effects on outcomes.
Setting:
General community.
Participants:
A total of 1654 community-dwelling men from the Offspring and Third Generation cohorts of the Framingham Heart Study.
Main Outcome Measures:
Coronary artery calcification (CAC), abdominal aortic calcification, and thoracic aortic calcification were measured by computed tomography.
Results:
Mean (standard deviation SD) age was 49 (10) years. Mean (SD) TT, cFT, and SHBG were: 616 (224) ng/dL, 111 (45) pg/mL, and 46 (23) nmol/L, respectively. Mean (SD) E2 and E1 were 28 (10) and 39 (14) pg/mL. Vascular calcification at all sites was negatively associated with TT and cFT and positively associated with E2 and E1. A 100-ng/dL between-subjects increase in TT was associated with a mean (95% confidence interval) age-adjusted difference in CAC of −23% (−41%, −4%) (P = .02). After model adjustment for other cardiovascular risk factors, the estimated associations between T and vascular calcification scores were statistically nonsignificant.
Conclusions:
Decreased circulating T and E2 levels are associated with an age-adjusted increase in CAC, but these associations appear to express relationships either attributable to or mediated by established cardiovascular risk factors.
Framingham Heart Study data suggest inverse associations between T, E2 levels and coronary artery calcification in aging men. Models suggest that established risk pathways underlie these associations.
Improvements in spatial and temporal resolution now permit robust high quality characterization of presence, morphology and composition of coronary atherosclerosis in computed tomography (CT). These ...characteristics include high risk features such as large plaque volume, low CT attenuation, napkin-ring sign, spotty calcification and positive remodeling. Because of the high image quality, principles of patient-specific computational fluid dynamics modeling of blood flow through the coronary arteries can now be applied to CT and allow the calculation of local lesion-specific hemodynamics such as endothelial shear stress, fractional flow reserve and axial plaque stress. This review examines recent advances in coronary CT image-based computational modeling and discusses the opportunity to identify lesions at risk for rupture much earlier than today through the combination of anatomic and hemodynamic information.
Copeptin, a stable peptide derived from the AVP precursor, has been linked to presence and severity of myocardial ischemia. We sought to evaluate the predictive value of copeptin and its incremental ...value beyond that of high-sensitivity cardiac troponin T (hs-cTnT) in patients with acute chest pain and low to intermediate risk for acute coronary syndrome (ACS).
We recruited patients who presented with acute chest pain to the emergency department and had a negative initial conventional troponin T test (<0.03 μg/L). In all patients, hs-cTnT and copeptin measurements were taken. Each patient also underwent cardiac computed tomography (CT) and coronary angiography.
Baseline copeptin concentrations, in contrast to hs-cTnT, were not significantly higher in patients with ACS than in those without (P = 0.24). hs-cTnT showed an earlier rise in patients with ACS than copeptin, when analyses were stratified by time. A copeptin concentration ≥7.38 pmol/L had a negative predictive value (NPV) of 94% and a sensitivity of 51%, whereas hs-cTnT (≥13.0 pg/mL) had a NPV of 96% and a sensitivity of 63%. The combination of copeptin and hs-cTnT resulted in a lower diagnostic accuracy than hs-cTnT alone. Finally, on cardiac CT, copeptin concentrations were not associated with coronary artery morphology, although they were related to the presence of left ventricular dysfunction (P = 0.02).
Among patients with acute chest pain and low to intermediate risk for ACS, copeptin concentrations are not independently predictive of ACS and do not add diagnostic value beyond that of hs-cTnT measurements.
Objectives
To evaluate whether iterative reconstruction algorithms improve the diagnostic accuracy of coronary CT angiography (CCTA) for detection of lipid-core plaque (LCP) compared to histology.
...Methods and materials
CCTA and histological data were acquired from three ex vivo hearts. CCTA images were reconstructed using filtered back projection (FBP), adaptive-statistical (ASIR) and model-based (MBIR) iterative algorithms. Vessel cross-sections were co-registered between FBP/ASIR/MBIR and histology. Plaque area <60 HU was semiautomatically quantified in CCTA. LCP was defined by histology as fibroatheroma with a large lipid/necrotic core. Area under the curve (AUC) was derived from logistic regression analysis as a measure of diagnostic accuracy.
Results
Overall, 173 CCTA triplets (FBP/ASIR/MBIR) were co-registered with histology. LCP was present in 26 cross-sections. Average measured plaque area <60 HU was significantly larger in LCP compared to non-LCP cross-sections (mm
2
: 5.78 ± 2.29 vs. 3.39 ± 1.68 FBP; 5.92 ± 1.87 vs. 3.43 ± 1.62 ASIR; 6.40 ± 1.55 vs. 3.49 ± 1.50 MBIR; all
p
< 0.0001). AUC for detecting LCP was 0.803/0.850/0.903 for FBP/ASIR/MBIR and was significantly higher for MBIR compared to FBP (
p
= 0.01). MBIR increased sensitivity for detection of LCP by CCTA.
Conclusion
Plaque area <60 HU in CCTA was associated with LCP in histology regardless of the reconstruction algorithm. However, MBIR demonstrated higher accuracy for detecting LCP, which may improve vulnerable plaque detection by CCTA.
Key Points
•
A low attenuation plaque area is associated with the presence of lipid
-
core plaque
•
MBIR leads to higher diagnostic accuracy for detecting lipid
-
core plaque
•
The benefit of MBIR is mainly due to increased sensitivity at high specificities
•
Semiautomated CCTA assessment can detect vulnerable plaques non
-
invasively
Objective
Prior studies on the association of physical activity (PA) and nonalcoholic fatty liver disease are limited by reliance on subjective measures of PA. We examined the association between ...objectively measured PA and hepatic steatosis defined by computed tomography (CT).
Methods
We conducted a cross‐sectional study of 1,060 Framingham Heart Study participants who participated in the Multidetector CT 2 substudy and who underwent assessment of PA via accelerometry. Hepatic steatosis was estimated by liver attenuation, as measured by CT. We explored the relationship between liver attenuation and PA using multivariable regression models.
Results
In multivariable‐adjusted models, we observed an inverse association between PA and liver attenuation. Each 30 minutes/day increase in moderate to vigorous PA (MVPA) was associated with a reduced odds of hepatic steatosis (OR = 0.62, P < 0.001). This association was attenuated and no longer statistically significant after adjustment for body mass index (BMI) (OR = 0.77, P = 0.05) or visceral adipose tissue (VAT) (OR = 0.83, P = 0.18). Participants who met the national PA recommendations of engaging in ≥150 minutes/week of MVPA had the lowest odds of hepatic steatosis, even after adjusting for BMI (OR = 0.63, P = 0.007) or VAT (OR = 0.67, P = 0.03).
Conclusions
There is an inverse association between PA and hepatic steatosis. Participants who met the national PA guidelines had the lowest prevalence of hepatic steatosis.
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