Ultrafast computed tomography as a diagnostic modality in the detection of coronary artery disease: a multicenter study

Assessing mortality risk in Type 2 Diabetes patients with prolonged ASCVD risk factors: the inclusive Poh-Ai predictive scoring system with CAC Score integration

PURPOSE

To enhance the predictive risk model for all-cause mortality in individuals with Type 2 Diabetes (T2DM) and prolonged Atherosclerotic Cardiovascular Disease (ASCVD) risk factors. Despite the utility of the Coronary Artery Calcium (CAC) score in assessing cardiovascular risk, its capacity to predict all-cause mortality remains limited.

METHODS

A retrospective cohort study included 1929 asymptomatic T2DM patients with ASCVD risk factors, aged 40-80. Variables encompassed demographic attributes, clinical parameters, CAC scores, comorbidities, and medication usage. Factors predicting all-cause mortality were selected to create a predictive scoring system. By using stepwise selection in a multivariate Cox proportional hazards model, we divided the patients into three risk groups.

RESULTS

In our analysis of all-cause mortality in T2DM patients with extended ASCVD risk factors over 5 years, we identified significant risk factors, their adjusted hazard ratios (aHR), and scores: e.g., CAC score > 1000 (aHR: 1.57, score: 2), CAC score 401-1000 (aHR: 2.05, score: 2), and more. These factors strongly predict all-cause mortality, with varying risk groups (e.g., very low-risk: 2.0%, very high-risk: 24.0%). Significant differences in 5-year overall survival rates were observed among these groups (log-rank test < 0.001).

CONCLUSION

The Poh-Ai Predictive Scoring System excels in forecasting mortality and cardiovascular events in individuals with Type 2 Diabetes Mellitus and extended ASCVD risk factors.

DiFiR-CT: Distance field representation to resolve motion artifacts in computed tomography

BACKGROUND

Motion during data acquisition leads to artifacts in computed tomography (CT) reconstructions. In cases such as cardiac imaging, not only is motion unavoidable, but evaluating the motion of the object is of clinical interest. Reducing motion artifacts has typically been achieved by developing systems with faster gantry rotation or via algorithms which measure and/or estimate the displacement. However, these approaches have had limited success due to both physical constraints as well as the challenge of estimating non-rigid, temporally varying, and patient-specific motion fields.

PURPOSE

To develop a novel reconstruction method which generates time-resolved, artifact-free images without estimation or explicit modeling of the motion.

METHODS

We describe an analysis-by-synthesis approach which progressively regresses a solution consistent with the acquired sinogram. In our method, we focus on the movement of object boundaries. Not only are the boundaries the source of image artifacts, but object boundaries can simultaneously be used to represent both the object as well as its motion over time without the need for an explicit motion model. We represent the object boundaries via a signed distance function (SDF) which can be efficiently modeled using neural networks. As a result, optimization can be performed under spatial and temporal smoothness constraints without the need for explicit motion estimation.

RESULTS

We illustrate the utility of DiFiR-CT in three imaging scenarios with increasing motion complexity: translation of a small circle, heart-like change in an ellipse's diameter, and a complex topological deformation. Compared to filtered backprojection, DiFiR-CT provides high quality image reconstruction for all three motions without hyperparameter tuning or change to the architecture. We also evaluate DiFiR-CT's robustness to noise in the acquired sinogram and found its reconstruction to be accurate across a wide range of noise levels. Lastly, we demonstrate how the approach could be used for multi-intensity scenes and illustrate the importance of the initial segmentation providing a realistic initialization. Code and supplemental movies are available at https://kunalmgupta.github.io/projects/DiFiR-CT.html.

CONCLUSIONS

Projection data can be used to accurately estimate a temporally-evolving scene without the need for explicit motion estimation using a neural implicit representation and analysis-by-synthesis approach.

Estimating the accuracy of dual energy chest radiography for coronary calcium detection with lateral or anteroposterior orientations

PURPOSE

Coronary artery calcium (CAC) scoring with CT has been studied as a risk stratification tool for cardiovascular disease. However, concerns remain from the radiation dose, economic expense, and incidental findings associated with this exam. Dual energy chest X-ray (DE CXR) has been proposed as an alternative, but validation of this technique remains limited. The purpose of this work was twofold: first, to estimate the sensitivity and specificity of DE CXR using simulation of patient datasets in a CAC screening cohort; second, to assess if sensitivity and specificity could be improved using a lateral instead of an anteroposterior (AP) orientation.

METHODS

We started from a cohort of 73 CAC scoring CT exams after exclusions for metal wires, data truncation, or with age outside 40-75 years. The fraction of CT CAC scores in the validation set of 0, 1-99, 100-299, and 300+ were 36, 25, 14, and 26%, respectively. CT datasets were decomposed on a voxel-by-voxel basis into mixtures of water and calcium according to CT number. DE CXR images were simulated using polyenergetic forward projection with scatter estimated from Monte Carlo. We assumed a technique of 60 and 120 kVp for the dual energy acquisition. The tube current was scaled such that the estimated radiation dose from DE CXR was 10 times less than CAC scoring CT. Patient motion was not simulated. Two readers read the validation set in a blinded, randomized fashion, and estimated the amount of CAC in each DE CXR image using a semiquantitative 4-point scale. Although patients present on a spectrum of CAC severity, in the primary analysis, sensitivity and specificity were calculated by dichotomizing patients into two categories of CT CAC (Agatston) scores of either 0-99 or 100+.

RESULTS

From the lateral orientation, average sensitivity between two readers was 69% (range, 69-69%), specificity was 85% (range, 84-86%), and area under the curve (AUC) was 0.81 (range, 0.80-0.81). From the AP orientation, average sensitivity was 35% (range, 31-38%), average specificity was 70% (range, 66-73%), and AUC was 0.54 (range, 0.53-0.55). Reader DE CXR scores agreed within 1 point of the 4-point scale on 97% of ratings from the lateral orientation and 80% from the AP orientation. From the lateral orientation, AUC increased when considering higher CT CAC score thresholds as disease positive; for thresholds of 1+, 300+, and 1000+, average AUC was 0.72, 0.81, and 0.92, respectively. From the AP orientation, AUC was 0.57, 0.55, and 0.61, respectively.

CONCLUSIONS

DE CXR for CAC scoring may have higher diagnostic accuracy when acquired from the lateral orientation. The sensitivity and specificity of lateral DE CXR, when combined with its modest cost and radiation dose, suggest a possible role for this technique in screening coronary calcium in lower risk individuals. These estimates of diagnostic accuracy are derived from simulation of patient datasets and have not been corroborated with experimental or clinical images.

Coronary computed tomography angiography as a screening tool for moderate-high risk asymptomatic type 2 diabetes mellitus patients

Background

There are few data on the clinical significance of coronary computed tomography angiography (CCTA) in asymptomatic type 2 diabetes mellitus (T2DM) patients. We performed a retrospective study to evaluate coronary heart disease (CHD) screening in asymptomatic patients with T2DM using CCTA and CHD risk stratification prediction.

Materials and methods

Data from 141 T2DM patients (58 ± 8 years, 57% males) without known symptoms suggestive of CHD who underwent CCTA were retrospectively analyzed. The patients were classified into three subgroups based on United Kingdom prospective diabetes study (UKPDS) CHD risk stratification prediction. Seventy-four patients without diabetes mellitus and CHD who underwent CCTA successively were chosen as the control group. The segment involvement score (SIS), segment stenosis score (SSS), stenosis coefficient (SC), severe proximal plaque (SPP) positive ratio and CCTA-adapted Leaman score (CT-LeSc) based on CCTA data were evaluated and compared among the groups.

Results

Compared with the patients in the control group, patients in the moderate-high risk DM groups had higher scores on the SIS, SSS, SC, CT-LeSc, and a higher SPP positive ratio (all p-values < 0.001), and no difference was observed between the low-risk group and the control group (p = 0.136, p = 0.088, p = 0.0.067, p = 0.225, p = 1.000, respectively). Compared with patients in the control group, the patients in the moderate-high risk DM groups had increased odds of SIS > 3 [odds ratio (OR) = 6.557, p < 0.001; OR = 4.455, p < 0.001, respectively], SSS > 5 (OR = 5.727, p < 0.001; OR = 5.144, p < 0.001, respectively), CT-LeSc > 8.7 (OR = 3.780, p = 0.001; OR = 2.804, p = 0.007, respectively), and obstructive stenosis (OR = 7.233, p < 0.001; OR = 5.787, p < 0.001, respectively).

Conclusion

The moderate-high CHD risk patients had increased odds of obstructive coronary artery stenosis, and the distribution of coronary artery stenosis was more extensive and more severe in that group compared to the patients without diabetes mellitus and CHD. CHD can be effectively screened in moderate-high risk asymptomatic T2DM patients using CCTA.

The relationship between serum vitamin K concentration and coronary artery calcification in middle-aged and elderly people

BACKGROUND

Vitamin K is involved in the formation of coronary artery calcification which is an independent predictor of coronary heart disease. This study aims to explore the association between coronary artery calcification score and serum concentrations of vitamin K1, menaquinone-4 (MK-4) and menaquinone-7 (MK-7) in middle-aged and elderly Chinese population.

METHODS

A total of 116 patients who underwent CT coronary angiography were consecutively enrolled. Serum concentrations of vitamin K1, MK-4 and MK-7 were determined by high performance liquid chromatography tandem mass spectrometry. The relationships between coronary artery calcification score and serum vitamin K concentrations were analyzed.

RESULTS

Significantly lower serum vitamin K1 concentration was found in the patients with CACS > 400, comparing with the other CACS categories, respectively. Log (CACS + 1) was significantly higher in MK-4 < 0.05 ng/ml group compared with MK-4 ≥ 0.05 ng/ml group [2.03(0.21, 2.58) vs 1.31(0.00, 2.19), P < 0.05]. In subjects with established coronary calcification (defined as CACS > 10), vitamin K1 was found to be an independent factor contributing to higher CACS (r = -0.288, P = 0.013).

CONCLUSIONS

In this retrospective analysis, serum vitamin K1 and MK-4 concentrations were significantly lower in middle-aged and elderly cohorts with increasing calcification scores. The significant effect of vitamin K1 on CACS was only found in individuals who already had calcification. Whether the detection of circulating vitamin K in patients with preexisting coronary calcification could guide vitamin K supplementation needs further exploration.

Assessment of Non-contrast-enhanced Dixon Water-fat Separation Compressed Sensing Whole-heart Coronary MR Angiography at 3.0 T: A Single-center Experience

RATIONALE AND OBJECTIVES

The clinical utility of Dixon water-fat separation coronary MR angiography (CMRA) with compressed sensing (CS) reconstruction has not been determined in a patient population. This study was designed to evaluate the performance of 3.0 T non-contrast-enhanced Dixon water-fat separation CS whole-heart CMRA sequence in vitro and in vivo.

MATERIALS AND METHODS

In vitro phantom MRI, we compared key parameters of the SENSE and CS images. And in this prospective in vivo study, from November 2019 to October 2020, 94 participants were recruited for 3.0 T non-contrast-enhanced Dixon water-fat separation CS whole-heart CMRA. The accuracy of CMRA for detecting a ≥ 50% reduction in diameter was determined using X-ray coronary angiography (CA) as the reference method.

RESULTS

Compared with SENSE, CS with an appropriate acceleration factor offers both higher SNR/CNR (p < 0.05) and a shortened acquisition. Fifty-eight patients successfully completed the CMRA and CA. The sensitivity, specificity, positive predictive values, negative predictive values, and accuracy of 3.0 T non-contrast-enhanced Dixon water-fat separation CS whole-heart CMRA according to a patient-based analysis were 96.4%, 66.7%, 73.0%, 95.2% and 81.0%, respectively. The area under the receiver-operator characteristic (ROC) curve (AUC) of 3.0 T non-contrast-enhanced Dixon water-fat separation CS whole-heart CMRA for detecting significant coronary artery stenosis is 0.908, 0.895, and 0.904 in patient-, vessel-, and segment-based analyses respectively.

CONCLUSION

3.0 T non-contrast-enhanced Dixon water-fat separation whole-heart CMRA using appropriate CS is a promising noninvasive and radiation-free technique to detect clinically significant coronary stenosis on patients with suspected CAD.

The Role of Cardiac Imaging in the Evaluation of Cardiac Involvement in Systemic Diseases

For systemic diseases like rheumatoid arthritis, systemic lupus erythematosus (SLE), systemic sclerosis, systemic vasculitis, myopathies, and mixed connective tissue diseases, cardiac disease is a major contributing factor for morbidity and mortality. The cardiovascular manifestations are the result of various pathophysiological components, which complicate management. Furthermore, the signs and symptoms can be subtle and missed due to the complex nature of the underlying condition. As a result, various imaging approaches play an imperative role in diagnosis and prognosis. The evolving role of these modalities could lead to risk stratification and improved therapies in the future. In conclusion, our review article will highlight the role of cardiac imaging in the evaluation of cardiac involvement for systemic diseases.

De-risking primary prevention: role of imaging

Atherosclerotic cardiovascular disease (ASCVD) is a common disease among the general population, and includes four major areas: (1) coronary heart disease (CHD), manifested by stable angina, unstable angina, myocardial infarction (MI), heart failure, and coronary death; (2) cerebrovascular disease, manifested by transient ischemia attack and stroke; (3) peripheral vascular disease, manifested by claudication and critical limb ischemia; and (4) aortic atherosclerosis and aortic aneurysm (thoracic and abdominal). CHD remains the leading cause of death for both men and women in the United States. So, it is imperative to identify people at risk of CHD and provide appropriate medical treatment or intervention to prevent serious complications and outcomes including sudden cardiac death. Coronary artery calcification (CAC) is a marker of subclinical coronary artery disease. Therefore, coronary artery calcium score is an important screening method for Coronary artery disease (CAD). In this article, we performed a comprehensive review of current literatures and studies assessing the prognostic value of CAC for future cardiovascular disease (CVD) events. We searched PubMed, MEDLINE, Google Scholar, and Cochrane library. We also reviewed the 2018 American College of Cardiology (ACC)/American Heart Association (AHA) guideline on the assessment of CVD risk. A CAC score of zero corresponds to very low CVD event rates (∼1% per year) and hence a potent negative risk marker. This has been referred to as the ‘power of zero’ and affords the lowest risk of any method of risk calculation. It is now indicated in the 2018 ACC/AHA Cholesterol guidelines to be used to avoid statins for 5–10 years after a score of zero, and then re-assess the patient.

Cytomegalovirus Donor Seropositivity Negatively Affects Survival After Heart Transplantation

OBJECTIVES

Prior studies have shown that cytomegalovirus(CMV) infection is a risk factor for the development of cardiac allograft vasculopathy(CAV) and is associated with reduced long-term survival after heart transplantation. The aim of this ISHLT Transplant Registry study was to compare post-transplant survival in different CMV donor:recipient serologic combinations.

METHODS

We performed a retrospective cohort study, using the ISHLT Thoracic Transplant Registry, on 15,885 adult primary heart transplant recipients with known CMV serologic status between 7/2004 and 6/2014. Post-transplant survival and risk of developing CAV were compared across 4 groups: CMV-seronegative recipients(R-) receiving CMV-positive grafts(D+), intermediate-risk patients(D+R+ and D-R+), and low-risk patients(D-R-).

RESULTS

Baseline characteristics (donor/recipient age, BMI, recipient serum creatinine, blood group, donor cause of death, recipient diagnosis and ischemic time) were mostly balanced between the groups. Kaplan Meier survival analyses over a follow up of 10 years revealed significantly worse survival for both D+ groups as compared to the CMV low risk group (D+R+:56.61% (95%CI 53.94,59.41) vs. D-R-:63.09% (59.74,66.64) p<.01 and D+R-:57.69% (56.03,59.39) vs. D-R-; p<.001), whereas recipient seropositivity alone was not associated with reduced survival (D-R+ vs. D-R- p=.178). The risk of developing CAV after HTx was not significantly increased in D+ as compared to D- groups.

CONCLUSION

In a large contemporary cohort, CMV status at the time of heart transplantation was not associated with CAV development. However, there was a significant association between donor CMV seropositivity and reduced short- and long-term survival after heart transplantation. Approaches to mitigate the impact of CMV on post-transplant survival are needed.Supplemental Visual Abstract; http://links.lww.com/TP/C292.

Simplifying the ISCHEMIA trial algorithm for clinical practice: Identifying left main coronary artery disease using coronary artery calcium scans

BACKGROUND

Several recent trials have evaluated invasive versus medical therapy for stable ischemic heart disease. Importantly, patients with significant left main coronary stenosis (LMCS) were excluded from these trials. In the ISCHEMIA trial, these patients were identified by a coronary CT angiogram (CCTA), which adds time, expense, and contrast exposure. We tested whether a coronary artery calcium scan (CACS), a simpler, less expensive test, could replace CCTA to exclude significant LMCS.

METHODS

We hypothesized that patients with ≥50% LMCS would have a LM CACS score > 0. As a corollary, we postulated that a LM CACS = 0 would exclude patients with LMCS. To test this, we searched Intermountain Healthcare's electronic medical records database for all adult patients who had undergone non-contrast cardiac CT for quantitative CACS scoring prior to invasive coronary angiography (ICA). Patients aged <50 and those with a heart transplant were excluded. Cases with incomplete (qualitative) angiographic reports for LMCS and those with incomplete or discrepant LM CACS results were reviewed and reassessed blinded to CACS or ICA findings, respectively.

RESULTS

Among 669 candidate patients with CACS followed by ICA, 36 qualifying patients were identified who had a quantitative CACS score and LMCS ≥ 50%. Their age averaged 71.8 years, and 81% were men. Angiographic LMCS averaged 72% (range 50%-99%). Median time between CACS and ICA was 6 days. Total CACS score averaged 2,383 Agatston Units (AU), range 571-6,636. LM CACS score averaged 197 AU, range 31-610. Importantly, no LMCS patient had a LM CACS score of 0 vs 57% (362/633) of non-LMCS controls (P < .00001).

CONCLUSIONS

Our results support the hypothesis that an easily administered, inexpensive, low radiation CACS can identify a large subset of patients with a very low risk of LMCS who would not have the need for routine CCTA. Using CACS to exclude LMCS may efficiently allow for safe implementation of an initial medical therapy strategy of patients with stable ischemic heart disease in clinical practice. These promising results deserve validation in larger data sets.

Coronary Artery Calcium: Where Do We Stand After Over 3 Decades?

In 2018, cardiovascular society cholesterol guidelines recommended the use of coronary artery calcium to guide statin therapy in patients 40-79 years of age who are at intermediate risk by multiple risk factor equations (ie, estimated 10-year risk for atherosclerotic disease of 7.5%-19.9% but in whom statin benefit is uncertain). Many such patients have no coronary calcium and remain at <5% risk over the next decade; hence, statin therapy can be delayed until a repeat calcium scan is conducted. Exceptions include patients with severe hypercholesterolemia, diabetes, and a strong family history of atherosclerotic disease. If coronary calcium equals 1-99 Agatston units, the 10-year risk is borderline (5% to <7.5%) and statin therapy is optional pending a repeat scan. If coronary calcium equals 100-299 Agatston units, the patient is clearly statin eligible (7.5% to <20% 10-year risk). And finally, if coronary calcium is ≥300 Agatston units, a patient is at high risk and is a candidate for high-intensity statins. Risk factor analysis combined judiciously with coronary calcium scanning offers the strongest evidence-based approach to use of statins in primary prevention.

Low-density lipoprotein cholesterol/apolipoprotein B ratio is superior to apolipoprotein B alone in the diagnosis of coronary artery calcification

OBJECTIVE

Coronary artery calcification (CAC) is closely associated with adverse coronary artery events and mortality. Measuring the extent of CAC can lead to the early diagnosis of coronary artery atherosclerosis. In this study, we determined the association between the low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (ApoB) ratio, ApoB, and CAC and compared the usefulness of the LDL-C/ApoB ratio and ApoB for diagnosing CAC.

METHODS

A total of 10 357 subjects who underwent self-paid health checkups from July 2006 to May 2016 were enrolled in this cross-sectional study. The extension of CAC was assessed using a coronary artery calcium score with electron-beam computed tomography. Subjects who had an Agatston calcium score >0 were defined as having CAC, whereas those with a score ≥400 were defined as having severe CAC. Low LDL-C/ApoB ratios were used to represent the predominance of small, dense LDL-C.

RESULTS

The prevalence of subjects with coronary calcification increased with the quartile values of ApoB levels and low quartile values of LDL-C/ApoB ratios. The odds ratios for CAC and severe CAC were 2.9 [95% confidence interval (CI), 2.2-3.9] and 4.4 (95% CI, 3.3-5.9) among the highest quartile of ApoB compared with the lowest quartile, and 9.5 (95% CI, 8.3-10.9) and 103.0 (95% CI, 56.9-187.8) among the lowest quartile of LDL-C/ApoB ratios compared with the highest quartile. The areas under the curve of ApoB and LDL-C/ApoB ratio for the diagnosis of CAC and severe CAC were 0.591 versus 0.679 and 0.618 versus 0.787, respectively. The LCL-C/ApoB ratio was superior to ApoB in terms of diagnosing subjects with CAC and severe CAC.

CONCLUSION

The LDL-C/ApoB ratio is a superior indicator to ApoB in the diagnosis of subjects with CAC, it can be conveniently used to improve the diagnostic ability of ApoB for CAC.

Histogram-derived modified thresholds for coronary artery calcium scoring with lower tube voltage

We aimed to determine the proper modified thresholds for detecting and weighting CAC scores at 100 kV through histogram matching in comparison with 120 kV as a standard reference. From the training set (680 participants), modified thresholds at 100 kV were obtained through histogram matching of calcium pixels to 120 kV. From the validation set (213 participants), a standard CAC score at 120 kV, and modified CAC score at 100 kV using modified thresholds were compare through the paired t test and the Bland–Altman plot. Agreement for risk categories (no, minimal, mild, moderate, and severe) was evaluated using kappa statistics. Radiation doses were also compared. For the validation set, there was no significant difference between standard (median, 18.7; IQR, 0.0–207.0) and modified (median, 17.3; IQR, 0.0–220.9) CAC scores (P = 0.689). A small bias was achieved (0.74) with 95% limits of agreement from − 52.35 to 53.83. Agreements for risk categories were excellent (κ = 0.994). The mean dose-length-product of 100-kV scanning (30.1 ± 0.8 mGy * cm) was significantly decreased compared to 120-kV scanning (42.9 ± 0.6 mGy * cm) (P < 0.001). Histogram-derived modified thresholds at 100 kV can enable accurate CAC scoring while reducing radiation exposure.

Sleep apnea, coronary artery calcium density and cardiovascular events: results from the Multi-Ethnic Study of Atherosclerosis (MESA)

STUDY OBJECTIVES

Evaluate the association between obstructive sleep apnea (OSA), coronary artery calcium (CAC) density, and cardiovascular events in the Multi-Ethnic Study of Atherosclerosis (MESA).

METHODS

We analyzed 1041 participants with non-zero CAC scores who had polysomnography and CAC density data from the fifth examination of MESA. OSA was defined as apnea-hypopnea index [AHI] ≥ 15 events/hour. Multivariable linear regression models were used to evaluate the independent association between OSA and CAC density. Additionally, we evaluated the impact of OSA on associations of CAC measures with incident CVD events by testing for interaction in Cox proportional hazard regression models.

RESULTS

Our analytical sample was 45% female with a mean age of 70.6 +/- 9 years. Of this sample, 36.7% (n=383/1041) had OSA (AHI≥15). OSA was inversely and weakly associated with CAC density (β= -0.09, 95% CI -0.17 to -0.02, p=0.014) and remained significantly associated after controlling for traditional cardiovascular risk factors (β= -0.08, 95% CI -0.16 to 0, p=0.043). However, this inverse association was attenuated after controlling for BMI (β=-0.05, 95% CI -0.13 to 0.02, p=0.174). The mean follow-up period for CVD events was 13.3 +/- 2.8 years. Additionally, exploratory analysis demonstrated that CAC density was independently and inversely associated with CVD events only in the non-OSA subgroup (AHI≤15) (HR 0.509 [CI 0.323 - 0.801], p=0.0035).

CONCLUSIONS

OSA was associated with lower CAC density, but this association was attenuated by BMI. Further, increased CAC density was associated with a reduced risk of CVD events only in individuals within the non-OSA group in exploratory analysis.

Association between waist-hip ratio and coronary artery calcification in postmenopausal women

Objective:

Many studies have reported that body composition might be associated with cardiovascular disease, but the issue has not been fully investigated in postmenopausal women.

Methods:

This retrospective study comprised 582 postmenopausal women without a history of cardiovascular disease who visited the Health Promotion Center between May 2008 and February 2018. All women were screened for body fat composition by bioelectrical impedance analysis and for degree of coronary artery calcification (CAC) by multidetector computed tomography. In addition, multivariate analysis, integrated discrimination improvement, and category-free net reclassification improvement were performed.

Results:

The level of triglycerides, and the waist-hip ratio (WHR) in participants with CAC (coronary artery calcium score [CACS] > 0) were higher than in participants with a CACS of zero points. When the participants were stratified into four groups according to WHR, participants with CAC (CACS > 0) increased significantly as WHR quartile increased. A multivariate analysis showed that older age (odds ratio [OR]: 2.539; 95% confidence interval [CI]: 1.524-4.230; P < 0.001), triglyceride level (OR: 1.005; 95% CI: 1.002-1.008; P = 0.003), WHR (OR: 1.103; 95% CI: 1.018-1.195; P = 0.017), and history of hypertension (OR: 2.701; 95% CI: 1.715-4.253; P < 0.001) were significantly associated with CAC. The Brier score upon adding WHR to a clinical model was lower than that of the clinical model without WHR. Adding WHR to a clinical model better predicted CAC than a clinical model without WHR (C index: 0.761, 95% CI: 0.724-0.795, P < 0.001; net reclassification improvement: 0.195, P = 0.037; integrated discrimination improvement: 1.02%, P = 0.043).

Conclusions:

In asymptomatic postmenopausal women, WHR as measured by bioelectrical impedance analysis was significantly associated with coronary atherosclerosis, supplementing information of usual clinical markers. Hence, WHR might be appropriate as a marker for early atherosclerosis.

Association between coronary artery calcium score and stent expansion in percutaneous coronary intervention

BACKGROUND

Measurement of the coronary artery calcification score using multidetector computed tomography (MDCT) is a useful noninvasive test for the diagnosis of coronary artery disease. However, whether pre-intervention assessment of the target vessel coronary artery calcification (TV-CAC) score is associated with stent expansion failure and future target lesion revascularization (TLR), remains unknown. This study aimed to determine the association between the TV-CAC score measured by MDCT and stent expansion rate in patients who underwent IVUS-guided PCI for stable angina.

METHODS

We conducted a retrospective observational study including 135 consecutive patients (186 target lesions) who underwent MDCT and were scheduled for the first PCI. The patients were divided into 2 groups based on the median value of the TV-CAC score. The primary outcome was the stent expansion rate measured by IVUS after stent implantation. The secondary outcome was TLR within 1 year.

RESULTS

Stent expansion rate was associated with the TV-CAC score (p < 0.001). According to the ROC curve analysis, the TV-CAC score had the largest area under the curve (AUC) for the stent expansion area of 0.90 (AUC = 0.893, p < 0.001). The TV-CAC score was a positive predictor for stent expansion rate of <90% (odds ratio: 7.54, p < 0.001). Mediation analysis showed that stent under-expansion was a mediator of the association between high TV-CAC and TLR.

CONCLUSIONS

Our study demonstrates that pre-intervention assessment of TV-CAC using MDCT is a predictor of stent expansion. The TV-CAC score might predict the complexity and help in the PCI operative strategy.

Coronary artery calcium scoring at lower tube voltages - Dose determination and scoring mechanism

PURPOSE

Population dose has been a concern with coronary artery calcium scoring CT since it is performed in adults with borderline risk. Lower tube voltage acquisitions are appealing but there are no agreed schemes for reduced dose determination. Moreover, conventional scoring cannot be used without changing the multiple Agatston thresholds.

METHODS

By applying consistent calcium contrast-to-noise ratio to two anthropomorphic heart phantoms (medium and large) with 3-cm hydroxyapatite (HA) inserts, scanned using a dual-source CT, the relationship was derived between the volume CT dose index (CTDI_vol) at lower tube voltages and the baseline CTDI_vol at 120 kVp. The baseline CTDI_vol was obtained using the noise thresholds from the images acquired at 120 kVp. To preserve the conventional Agatston thresholds, down-scaling with the found factors was applied to images acquired at lower voltages with a dynamic heart module and 1.2-5 mm inserts (50-400 mg/cc) on the coronary tracks. Scores were evaluated on the scaled images by six readers.

RESULTS

The CTDI_vol at lower voltages was related to the baseline CTDI_vol following a power form of the voltage (index 1.246), regardless of the phantom size. The baseline CTDI_vol was 1.5 and 4.5 mGy, for the medium and large phantoms, respectively. Correspondingly, the reduced CTDI_vol at 100-70 kVp were 1.28-0.76 mGy, and 3.57-2.32 mGy. The downscaling factors were 0.88-0.63. The calcium scores at lower voltages were found within 12 % of the ground-truths.

CONCLUSION

A vendor-independent approach was established to obtain the reduced dose and correct coronary calcium scores at lower tube voltages.

Role of Coronary Calcium Score to Identify Candidates for ASCVD Prevention

PURPOSE OF REVIEW

In this review, we describe the mechanism behind coronary artery calcification formation and detection, as well as its implication in cardiovascular disease (CVD) risk stratification, intervention, and prognosis in asymptomatic individuals.

RECENT FINDINGS

Multiple cohort and population studies have shown that coronary artery calcium scoring is effective and reproducible in predicting the risk for cardiovascular disease. The updated 2018 ACC/AHA guideline has incorporated consideration of coronary artery calcification testing into cardiovascular disease risk stratification and therapy guidance. Coronary artery calcification's evidence-based role in detection, risk stratification, and ultimately its unique influence on therapeutic intervention and prognosis of cardiovascular disease in asymptomatic population is increasingly being recognized..

Postsystolic shortening on echocardiography as a gateway to cardiac computed tomography in patients with suspected stable angina pectoris

Postsystolic shortening (PSS) by speckle-tracking echocardiography (STE) is a marker of myocardial ischemia and may improve diagnostic strategy. We sought to evaluate if PSS is associated with the coronary artery calcium score (CACS) and stenosis by computed tomography angiography (CTA) in patients with suspected stable angina pectoris (SAP). We retrospectively studied 437 SAP patients (age 58 ± 11 years, 41% male) who underwent STE, evaluation of CACS and assessment of significant stenosis (≥ 50%) by CTA. The postsystolic index (PSI) was defined as follows: 100x([peak negative strain cardiac cycle - peak negative strain systole])/peak negative strain cardiac cycle. A wall had PSS if any segment within the wall had a PSI ≥ 20%. We defined categories for walls with PSS: 0, 1, 2 and ≥ 3, and CACS: 0, 1-100, 101-400 and > 400. Each additional wall with PSS was associated with a 43% relative increase in CACS (95%CI +9% to +87%, P = 0.010), while each 1% absolute increase in the PSI was associated with a 9% relative increase in CACS (95%CI +1% to +18%, P = 0.031). Walls with PSS (OR 1.81 per 1 wall increase, 95%CI 1.27-2.59, P = 0.001) and the PSI (OR 1.12 per 1% increase, 95%CI 1.04-1.21, P = 0.004) were associated with the occurrence of CACS > 400. Additionally, walls with PSS (OR 1.53 per 1 wall increase, 95%CI 1.21-1.93, P < 0.001) was a predictor of significant stenosis by CTA. PSS is associated with CACS and significant stenosis by CTA in patients with SAP and may aid in the selection of patients referred for cardiac computed tomography.

Prevalence of and Risk Factors for Diseases in Korean Americans and Native Koreans Undergoing Health Checkup

BACKGROUND

Korean Americans constitute the fifth largest subgroup in the Asian American population. Despite their increasing population, research and guidelines regarding their health status assessment and disease screening are lacking. This study aimed to compare the prevalence of diseases in Korean Americans and native Koreans to determine the risk factors and guidelines for disease screening.

METHODS

Patients who visited the Gangnam Severance Hospital from February 2010 to May 2015 for a health checkup were enrolled in this study. Baseline characteristics, laboratory data, and the organs (stomach, colon, thyroid, brain, prostate, lung, liver, kidney, pancreas, adrenal gland, and heart) of patients were examined. Data regarding patients' dietary patterns were also obtained. Overall, 1,514 Korean Americans (group 1) and 1,514 native Koreans (group 2) were enrolled.

RESULTS

The following diseases were more prevalent in group 1 than in group 2: reflux esophagitis (12.9% vs. 10%), gastric ulcer (3.0% vs. 5.5%), colorectal polyp (37.7% vs. 28.7%), hemorrhoids (32.2% vs. 29.9%), and benign prostatic hyperplasia (30.2% vs. 14.3%). Although not statistically significant, coronary artery disease has a high prevalence rate of >20% in both groups. Dietary patterns were not significant between the two groups.

CONCLUSION

This study showed that the prevalence of several diseases in Korean Americans differed from that observed in native Koreans. Therefore, a foundation for setting up new guidelines for disease screening among Korean Americans is established.

Cardiorespiratory Fitness and Coronary Artery Calcification in a Primary Prevention Population

Objective

To elucidate whether cardiorespiratory fitness (CRF) is protective or contributory to coronary artery disease plaque burden.

Patients and Methods

Study participants were working middle-aged men from the Mayo Clinic Executive Health Program who underwent coronary artery calcium (CAC) assessment and exercise treadmill testing for risk stratification. Data from January 1, 1995, through December 31, 2008, were considered. The CAC assessment score was used for lifelong plaque burden analysis; functional aerobic capacity (FAC) from treadmill testing was analyzed as 4 ranked categories of CRF. Known risk factors for cardiovascular disease, including family history, were also considered.

Results

In 2946 male patients in this retrospective, cross-sectional, observational study, known cardiovascular risk factor profiles and risk calculations tended to uniformly improve with increasing CRF, defined by the FAC level. Only the above-average group, or the third of 4 levels, was found consistently lower than other levels of FAC for CAC scores. The above-average group also had statistical significance after controlling for age, body mass index, and family history of coronary artery disease in a U-shaped distribution rather than the expected linear dose-response relationship. Plaque burden was significantly increased in patients with the highest FAC level (P=.005) compared with the above-average group despite the observed maximal risk factor optimization in all known conventional cardiovascular risk factors.

Conclusion

For men, maximal CRF is associated with increased atherosclerosis, established with CAC scores. By comparison, average-to-moderate CRF appears to be cardioprotective regardless of either age or the influence of other contributing, recognized cardiac risk factors.

On the data acquisition, image reconstruction, cone beam artifacts, and their suppression in axial MDCT and CBCT - A review

PURPOSE

In the clinic, computed tomography (CT) has evolved into an essential modality for diagnostic imaging by multidetector row CT (MDCT) and image guided intervention by cone beam CT (CBCT). Recognizing the increasing importance of axial MDCT/CBCT in clinical and preclinical applications, and the existence of CB artifacts in MDCT/CBCT images, we provide a review of CB artifacts' root causes, rendering mechanisms and morphology, and possible solutions for elimination and/or reduction of the artifacts.

METHODS

By examining the null space in Radon and Fourier domain, the root cause of CB artifacts (i.e., data insufficiency) in axial MDCT/CBCT is analytically investigated, followed by a review of the data sufficiency conditions and the "circle +" source trajectories. The rendering mechanisms and morphology of CB artifacts in axial MDCT/CBCT and their special cases (e.g., half/short scan and full scan with latitudinally displaced detector) are then analyzed, followed by a survey of the potential solutions to suppress the artifacts. The phenomenon of imaged zone indention and its variation over FBP, BPF/DBPF, two-pass and iterative CB reconstruction algorithms and/or schemes are discussed in detail.

RESULTS

An interdomain examination of the null space provides an insightful understanding of the root cause of CB artifacts in axial MDCT/CBCT. The decomposition of CB artifacts rendering mechanisms facilitates understanding of the artifacts' behavior under different conditions and the potential solutions to suppress them. An inspection of the imaged zone intention phenomenon provides guidance on the design and implementation of CB image reconstruction algorithms and schemes for CB artifacts suppression in axial MDCT/CBCT.

CONCLUSIONS

With increasing importance of axial MDCT/CBCT in clinical and preclinical applications, this review article can update the community with in-depth information and clarification on the latest progress in dealing with CB artifacts and thus increase clinical/preclinical confidence.

Coronary Artery Calcium Scoring: Is It Time for a Change in Methodology?

Quantification of coronary artery calcium (CAC) has been shown to be reliable, reproducible, and predictive of cardiovascular risk. Formal CAC scoring was introduced in 1990, with early scoring algorithms notable for their simplicity and elegance. Yet, with little evidence available on how to best build a score, and without a conceptual model guiding score development, these scores were, to a large degree, arbitrary. In this review, we describe the traditional approaches for clinical CAC scoring, noting their strengths, weaknesses, and limitations. We then discuss a conceptual model for developing an improved CAC score, reviewing the evidence supporting approaches most likely to lead to meaningful score improvement (for example, accounting for CAC density and regional distribution). After discussing the potential implementation of an improved score in clinical practice, we follow with a discussion of the future of CAC scoring, asking the central question: do we really need a new CAC score?

The Correlation of Dyslipidemia with the Extent of Coronary Artery Disease in the Multiethnic Study of Atherosclerosis

Background

The extent of coronary artery calcium (CAC) improves cardiovascular disease (CVD) risk prediction. The association between common dyslipidemias (combined hyperlipidemia, simple hypercholesterolemia, metabolic Syndrome (MetS), isolated low high-density lipoprotein cholesterol, and isolated hypertriglyceridemia) compared with normolipidemia and the risk of multivessel CAC is underinvestigated.

Objectives

To determine whether there is an association between common dyslipidemias compared with normolipidemia, and the extent of coronary artery involvement among MESA participants who were free of clinical cardiovascular disease at baseline.

Methods

In a cross-sectional analysis, 4,917 MESA participants were classified into six groups defined by specific LDL-c, HDL-c, or triglyceride cutoff points. Multivessel CAC was defined as involvement of at least 2 coronary arteries. Multivariate Poisson regression analysis evaluated the association of each group with multivessel CAC after adjusting for CVD risk factors.

Results

Unadjusted analysis showed that all groups except hypertriglyceridemia had statistically significant prevalence ratios of having multivessel CAC as compared to the normolipidemia group. The same groups maintained statistical significance prevalence ratios with multivariate analysis adjusting for other risk factors including Agatston CAC score [combined hyperlipidemia 1.41 (1.06-1.87), hypercholesterolemia 1.55 (1.26-1.92), MetS 1.28 (1.09-1.51), and low HDL-c 1.20 (1.02-1.40)].

Conclusion

Combined hyperlipidemia, simple hypercholesterolemia, MetS, and low HDL-c were associated with multivessel coronary artery disease independent of CVD risk factors and CAC score. These findings may lay the groundwork for further analysis of the underlying mechanisms in the observed relationship, as well as for the development of clinical strategies for primary prevention.

Current Helicobacter pylori infection is significantly associated with subclinical coronary atherosclerosis in healthy subjects: A cross-sectional study

Helicobacter pylori is a gastrointestinal pathogen known to be associated with cardiovascular disease (CVD). However, most analyses about the effect of H. pylori infection have been done in patients with a history of CVD but not in healthy subjects. We evaluated the association between H. pylori infection and subclinical atherosclerosis by using cardiac multidetector computed tomography (MDCT) in healthy subjects without previous CVD. From December 2007 to February 2014, 463 subjects who underwent the rapid urease test (CLO test), pulse-wave velocity (PWV) measurement, and MDCT for a self-referred health check-up were enrolled to this study. Helicobacter pylori infection was defined on the basis of CLO test positivity on endoscopic gastric biopsy. Significant coronary artery stenosis was defined as ≥50% stenosis in any of the major epicardial coronary vessel on MDCT. The CLO-positive subjects had a lower high-density lipoprotein-cholesterol (HDL-cholesterol) level compared to the CLO-negative subjects. The incidence of significant coronary stenosis was higher in the CLO-positive group (7.6% vs. 2.9%, P = 0.01). Furthermore, the number of subjects with coronary artery calcium score >0 and log{(number of segments with plaque)+1} were also significantly higher in the CLO-positive group. However, there was no statistical difference in the number of subjects with coronary artery calcium score >100, the prevalence of any plaque nor the plaque characteristics (calcified, mixed, or soft). Pulse-wave velocity (PWV) was neither associated with CLO test positivity. The CLO-positive group was 3-fold more likely to have significant coronary artery stenosis even after adjusting for confounding factors (adjusted odds ratio 2.813, 95% confidence interval 1.051–7.528, P = 0.04). In a healthy population, current H. pylori infection was associated with subclinical but significant coronary artery stenosis. The causal relationship between H. pylori infection and subclinical atherosclerosis in a “healthy” population remains to be investigated in the future.

Elevated serum uric acid predicts the development of moderate coronary artery calcification independent of conventional cardiovascular risk factors

BACKGROUND AND AIMS

Hyperuricemia was frequently noted in subjects with a high risk of cardiovascular disease (CVD). This study aimed to elucidate whether serum uric acid (SUA) is associated with development of moderate coronary artery calcification in generally healthy adults.

METHODS

A total of 9297 subjects underwent multidetector CT for the evaluation of CAC at least two times during their annual health examinations. Among them, 4461 participants without CVD history and who had no (scores 0) or minimal CAC (scores 1-10) in their first examination were enrolled. The association between SUA as a continuous and categorical variable and development of moderate coronary artery calcification (CAC score > 100) was assessed by Cox regression analysis. Receiver-operating characteristic (ROC) curves were constructed to investigate the diagnostic efficacy of SUA.

RESULTS

During a median follow-up of 4.1 years, 131 incident cases of moderate calcification developed. Baseline SUA concentration was significantly higher in subjects with progression to moderate coronary artery calcification (6.6 ± 1.3 vs. 5.8 ± 1.3 mg/dL, p < 0.001). SUA as a continuous variable (per 1 mg/dL) and divided into quartiles was positively associated with a higher risk of development of moderate calcification after adjustment for conventional CVD risk factors. The addition of SUA to the conventional CVD risk factors improved the predictive power for development of moderate coronary artery calcification.

CONCLUSIONS

SUA was an independent predictor for development of moderate coronary artery calcification in subjects with no or minimal calcification.

Evaluation of Atherosclerotic Plaque in Non-invasive Coronary Imaging

Coronary artery disease (CAD) is the leading cause of morbidity and mortality worldwide. Over the last decade coronary computed tomography angiography (CCTA) has gained wide acceptance as a reliable, cost-effective and non-invasive modality for diagnosis and prognostication of CAD. Use of CCTA is now expanding to characterization of plaque morphology and identification of vulnerable plaque. Additionally, CCTA is developing as a non-invasive modality to monitor plaque progression, which holds future potential in individualizing treatment. In this review, we discuss the role of CCTA in diagnosis and management of CAD. Additionally, we discuss the recent advancements and the potential clinical applications of CCTA in management of CAD.

Coronary Artery Calcium Distribution Is an Independent Predictor of Incident Major Coronary Heart Disease Events: Results From the Framingham Heart Study

BACKGROUND

The presence and extent of coronary artery calcium (CAC) are associated with increased risk for cardiovascular events. We determined whether information on the distribution of CAC and coronary dominance as detected by cardiac computed tomography were incremental to traditional Agatston score (AS) in predicting incident major coronary heart disease (CHD).

METHODS AND RESULTS

We assessed total AS and the presence of CAC per coronary artery, per segment, and coronary dominance by computed tomography in participants from the offspring and third-generation cohorts of the Framingham Heart Study. The primary outcome was major CHD (myocardial infarction or CHD death). We performed multivariable Cox proportional hazards analysis and calculated relative integrated discrimination improvement. In 1268 subjects (mean age, 56.2±10.3 years, 63.2% men) with AS >0 and no history of major CHD, a total of 42 major CHD events occurred during median follow-up of 7.4 years. The number of coronary arteries with CAC (hazard ratio, 1.68 per artery; 95% confidence interval, 1.10-2.57; P=0.02) and the presence of CAC in the proximal dominant coronary artery (hazard ratio, 2.59; 95% confidence interval, 1.15-5.83; P=0.02) were associated with major CHD events after multivariable adjustment for Framingham risk score and categories of AS. In addition, measures of CAC distribution improved discriminatory capacity for major CHD events (relative integrated discrimination improvement, 0.14).

CONCLUSIONS

Distribution of coronary atherosclerosis, especially CAC in the proximal dominant coronary artery and an increased number of coronary arteries with CAC, predict major CHD events independently of the traditional AS in community-dwelling men and women.

Variable temporal sampling and tube current modulation for myocardial blood flow estimation from dose-reduced dynamic computed tomography

Quantification of myocardial blood flow (MBF) can aid in the diagnosis and treatment of coronary artery disease. However, there are no widely accepted clinical methods for estimating MBF. Dynamic cardiac perfusion computed tomography (CT) holds the promise of providing a quick and easy method to measure MBF quantitatively. However, the need for repeated scans can potentially result in a high patient radiation dose, limiting the clinical acceptance of this approach. In our previous work, we explored techniques to reduce the patient dose by either uniformly reducing the tube current or by uniformly reducing the number of temporal frames in the dynamic CT sequence. These dose reduction techniques result in noisy time-attenuation curves (TACs), which can give rise to significant errors in MBF estimation. We seek to investigate whether nonuniformly varying the tube current and/or sampling intervals can yield more accurate MBF estimates for a given dose. Specifically, we try to minimize the dose and obtain the most accurate MBF estimate by addressing the following questions: when in the TAC should the CT data be collected and at what tube current(s)? We hypothesize that increasing the sampling rate and/or tube current during the time frames when the myocardial CT number is most sensitive to the flow rate, while reducing them elsewhere, can achieve better estimation accuracy for the same dose. We perform simulations of contrast agent kinetics and CT acquisitions to evaluate the relative MBF estimation performance of several clinically viable variable acquisition methods. We find that variable temporal and tube current sequences can be performed that impart an effective dose of 5.5 mSv and allow for reductions in MBF estimation root-mean-square error on the order of 20% compared to uniform acquisition sequences with comparable or higher radiation doses.

Diagnosis of fatty liver by computed tomography coronary artery calcium score

Nonalcoholic fatty liver disease may range from simple steatosis to fibrosis and cirrhosis. It is associated with the development of coronary artery calcification and appears to be an independent predictor of future adverse cardiovascular events. As the presence of a fatty liver appears to portray an independent increased risk, it may be beneficial to note this on coronary artery calcium scoring reports. Determination of fatty liver is relatively easy to perform. We discuss the method used by the Multi-Ethnic Study of Atherosclerosis (MESA) study for determination of fatty liver from CT coronary artery calcium scoring acquisitions, which may be implemented in clinical analysis.

Assessment of coronary artery calcium by chest CT compared with EKG-gated cardiac CT in the multicenter AIDS cohort study

Rationale

Individuals with HIV are at increased risk for coronary artery disease (CAD). Early detection of subclinical CAD by assessment of coronary artery calcium (CAC) may help risk stratify and prevent CAD events in these individuals. However, the current standard to quantify CAC i.e. Agatston scoring requires EKG-gated cardiac CT imaging.

Objective

To determine if the assessment of CAC using non-EKG-gated chest CT and the Weston scoring system is a useful surrogate for Agatston scores in HIV-infected and HIV-uninfected individuals.

Methods and measurements

CAC was assessed by both the Weston and Agatston score in 108 men enrolled in the Multicenter AIDS Cohort Study.

Results

Participants were 55.2 (IQR 50.4; 59.9) years old and 62 (57.4%) were seropositive for HIV. Inter-observer agreement (r_s = 0.94, κ = 90.0%, p<0.001, n = 21) and intra-observer agreement (r_s = 0.95, κ = 95.2%, p<0.001, n = 97) for category of Weston score were excellent. Weston scores were associated with similar CAD risk factors as Agatston scores (age, race, HDL cholesterol level, all p<0.05) in our cohort. There was excellent correlation (r_s = 0.92, p<0.001) and agreement (κ_w = 0.77, p<0.001) between Weston and Agatston scores.

Conclusions

This study is the first to examine calcium scoring using chest CT in HIV-infected individuals and to independently validate the Weston score as a surrogate for the Agatston score. In clinical or research settings where EKG-gated cardiac CT is not feasible for the assessment of coronary calcium, Weston scoring by using chest CT should be considered.

Renal function had an independent relationship with coronary artery calcification in Chinese elderly men

BACKGROUND

Although previous studies have analyzed the relationship between renal function and coronary artery calcification (CAC) in pre-dialysis and dialysis patients, limited studies have discussed the relationship between renal function and CAC in Chinese elderly men without obvious damage of renal function. The present study was designed to explore the relationship between renal function and CAC in Chinese elderly men without obvious damage of renal function.

METHODS

This cross-sectional study was carried out in 105 male participants older than 60 years with glomerular filtration rate (GFR) ≥ 45 ml/min/1.73 m². CAC was detected by high-definition computerized tomography (HDCT), which is a highly sensitive technique for detecting the CAC and provides the most accurate CAC scores up to date.

RESULTS

Age was 72 ± 8.4 years on average and ranged from 60 to 89 years. Simple correlation analysis indicated that all kinds of CAC scores including the Agatston, volume and mass scores inversely correlated with GFR values (p < 0.05 for all). In multivariate linear regression analysis, GFR values were independently associated with all these CAC scores (p < 0.05 for all).

CONCLUSION

Renal function had an independent relationship with CAC detected by HDCT in Chinese elderly men, demonstrating that the relationship between renal function and CAC started at the early stage of renal function decline.

Prognostic Value of Combined CT Angiography and Myocardial Perfusion Imaging versus Invasive Coronary Angiography and Nuclear Stress Perfusion Imaging in the Prediction of Major Adverse Cardiovascular Events: The CORE320 Multicenter Study

Purpose To compare the prognostic importance (time to major adverse cardiovascular event [MACE]) of combined computed tomography (CT) angiography and CT myocardial stress perfusion imaging with that of combined invasive coronary angiography (ICA) and stress single photon emission CT myocardial perfusion imaging. Materials and Methods This study was approved by all institutional review boards, and written informed consent was obtained. Between November 2009 and July 2011, 381 participants clinically referred for ICA and aged 45-85 years were enrolled in the Combined Noninvasive Coronary Angiography and Myocardial Perfusion Imaging Using 320-Detector Row Computed Tomography (CORE320) prospective multicenter diagnostic study. All images were analyzed in blinded independent core laboratories, and a panel of physicians adjudicated all adverse events. MACE was defined as revascularization (>30 days after index ICA), myocardial infarction, or cardiac death; hospitalization for chest pain or congestive heart failure; or arrhythmia. Late MACE was defined similarly, except for patients who underwent revascularization within the first 182 days after ICA, who were excluded. Comparisons of 2-year survival (time to MACE) used standard Kaplan-Meier curves and restricted mean survival times bootstrapped with 2000 replicates. Results An MACE (49 revascularizations, five myocardial infarctions, one cardiac death, nine hospitalizations for chest pain or congestive heart failure, and one arrhythmia) occurred in 51 of 379 patients (13.5%). The 2-year MACE-free rates for combined CT angiography and CT perfusion findings were 94% negative for coronary artery disease (CAD) versus 82% positive for CAD and were similar to combined ICA and single photon emission CT findings (93% negative for CAD vs 77% positive for CAD, P < .001 for both). Event-free rates for CT angiography and CT perfusion versus ICA and single photon emission CT for either positive or negative results were not significantly different for MACE or late MACE (P > .05 for all). The area under the receiver operating characteristic curve (AUC) for combined CT angiography and CT perfusion (AUC = 68; 95% confidence interval [CI]: 62, 75) was similar (P = .36) to that for combined ICA and single photon emission CT (AUC = 71; 95% CI: 65, 79) in the identification of MACE at 2-year follow-up. Conclusion Combined CT angiography and CT perfusion enables similar prediction of 2-year MACE, late MACE, and event-free survival similar to that enabled by ICA and single photon emission CT. ^© RSNA, 2017 Online supplemental material is available for this article.

Serum osteoprotegrin (OPG) in subclinical atherosclerosis in systemic lupus erythematosus

Introduction Osteoprotegerin (OPG) is a member of the tumor necrosis factor (TNF) receptor family. It has recently been demonstrated that OPG is produced by a variety of tissues, including the cardiovascular system (heart, arteries, veins), lung, kidney, immune tissues, and bone. The OPG-RANKL signaling pathway is strongly related to vascular calcification. We determined the association of this biomarker with subclinical atherosclerosis in systemic lupus erythematous (SLE). Methods We measured OPG and markers of subclinical atherosclerosis (coronary artery calcium (CAC), carotid intima-media thickness (cIMT) carotid plaque) in 166 SLE patients (91% female, 64% Caucasian, 31% African American, 5% others, mean age 45 years). Subgroups of patients with different levels of OPG level were compared with respect to average levels of CAC, cIMT, and with respect to presence of carotid plaque. Age was adjusted for using multiple regression. Results OPG was highly correlated with age ( p < 0.0001). Individuals with higher levels of OPG tended to have higher measures of CAC, cIMT, and more carotid plaque. However, after adjustment for age, these associations, while still positive, were no longer statistically significant. Conclusion In our study much of the association observed was due to confounding by age, and after adjusting for age, our findings do not rule out the possibility of a null association.

Identifying Small Coronary Calcification in Non-Contrast 0.5-mm Slice Reconstruction to Diagnose Coronary Artery Disease in Patients with a Conventional Zero Coronary Artery Calcium Score

Aims: In a new-generation computed tomography (CT) scanner, coronary artery calcium (CAC) scores were measured using 3.0-mm slice reconstruction images originally acquired with 0.5 mm thickness scans in a single beat. This study investigated the usefulness of thin-slice (0.5 mm) reconstruction for identifying small calcifications in coronary arteries and evaluated the association with coronary plaques and stenosis compared to conventional 3.0-mm reconstruction images.

Methods: We evaluated 132 patients with zero CAC scores in conventional 3.0-mm Agatston method using a 320-slice CT. Then, 0.5-mm slice reconstruction was performed to identify small calcifications. The presence of stenosis and coronary plaques was assessed using coronary CT angiography.

Results: In total, 22 small calcifications were identified in 18 patients. There were 28 (21%) patients with any (≥ 25%) stenosis (34 lesions). Forty-seven coronary plaques were found in 33 patients (25%), including 7 calcified plaques in 7 patients (5%), 34 noncalcified plaques in 27 patients (20%), and 6 partially calcified plaques in 5 patients (4%). Patients with small calcifications had a significantly higher prevalence of noncalcified or partially calcified plaques (83% vs 14%; p < 0.001) and obstructive stenosis (33% vs 5.2%; p < 0.001) compared to those without small calcifications. The addition of small calcifications to the coronary risk factors when diagnosing stenosis significantly improved the diagnostic value.

Conclusion: Small calcifications detected by thin-slice 0.5-mm reconstruction are useful for distinguishing coronary atherosclerotic lesions in patients with zero CAC scores from conventional CT reconstruction.

Aortic valve calcification in systemic lupus erythematosus

Aortic valve calcification is associated with atherosclerosis in the general population. We investigated the prevalence of and associates of aortic valve calcification in systemic lupus erythematosus (SLE). One-hundred and ninety-nine SLE patients enrolled in a clinical trial had aortic valve calcification assessed by helical CT. The patients had a mean age of 44.3 = 11.4 years and were 92% female, 61% Caucasian, 34% African-American, 2% Asian and 2% Hispanic. Aortic valve calcification was present in 1.5%, whereas coronary calcium was found in 43% and carotid plaque in 17%. Among cardiovascular risk factors, hs-CRP ( P = 0.0592), fibrinogen ( P = 0.0507), and lipoprotein(a) ( P = 0.0250), were associated with aortic valve calcification. Prednisone use ( P = 0.049) and use of methotrexate ( P = 0.0174) were also associated with aortic valve calcification. Aortic valve calcification was associated with antiphospholipid antibody positivity (0.0287) (lupus anticoagulant, by dilute Russell viper venom time). It was not associated with coronary calcium or carotid plaque. Aortic valve calcification, although rare in SLE, was associated with some novel cardiovascular risk factors and with a marker of hypercoagulability (lupus anticoagulant). In contrast to the general population, aortic valve calcification in SLE is not associated with subclinical measures of atherosclerosis, such as coronary calcium or carotid plaque.

Tracking Progression of Heart Disease with Cardiac Computed Tomography

The ability to follow changes in atherosclerotic plaque burden over time should provide an accurate measure of efficacy for different cardiovascular therapies. Coronary calcifications are associated with atherosclerotic coronary artery plaque, and the amount of coronary calcifications has been shown to correlate with the overall coronary plaque burden. The presence and extent of coronary calcifications can be assessed noninvasively by monitoring the progression of coronary calcification with electron beam tomography. With annual progression rates of 22% to 52% and a median interscan variability of only 5% to 8%, this technology provides an opportunity to monitor patients to assess the clinical efficacy of medical therapies in studies as short as 1 year. Several studies have demonstrated that the successful pharmacologic reduction of low-density lipoprotein cholesterol significantly mitigated the progression of the calcium score. Studies using serial computed tomographic scans indicate that the annual progression of coronary calcium varies between 30% and 50% in symptomatic or high-risk individuals and from 0% to 20% in patients treated effectively with lipid-lowering medication. An increased rate of progression of coronary calcium seems to indicate a substantially increased risk for adverse cardiac events, suggesting that this modality can be used to monitor the efficacy of therapy.

Improving the CAC Score by Addition of Regional Measures of Calcium Distribution: Multi-Ethnic Study of Atherosclerosis

OBJECTIVES

The aim of this study was to investigate whether inclusion of simple measures of calcified plaque distribution might improve the ability of the traditional Agatston coronary artery calcium (CAC) score to predict cardiovascular events.

BACKGROUND

Agatston CAC scoring does not include information on the location and distributional pattern of detectable calcified plaque.

METHODS

We studied 3,262 (50%) individuals with baseline CAC >0 from MESA (Multi-Ethnic Study of Atherosclerosis). Multivessel CAC was defined by the number of coronary vessels with CAC (scored 1 to 4, including the left main). The "diffusivity index" was calculated as: 1 - (CAC in most affected vessel/total CAC), and was used to group participants into concentrated and diffuse CAC patterns. Multivariable Cox proportional hazards regression, area under the curve, and net reclassification improvement analyses were performed for both coronary heart disease (CHD) and cardiovascular disease (CVD) events to assess whether measures of regional CAC distribution add to the traditional Agatston CAC score.

RESULTS

Mean age of the population was 66 ± 10 years, with 42% women. Median follow-up was 10.0 (9.5 to 10.7) years and there were 368 CHD and 493 CVD events during follow-up. Considerable heterogeneity existed between CAC score group and number of vessels with CAC (p < 0.01). Addition of number of vessels with CAC significantly improved capacity to predict CHD and CVD events in survival analysis (hazard ratio: 1.9 to 3.5 for 4-vessel vs. 1-vessel CAC), area under the curve analysis (C-statistic improvement of 0.01 to 0.033), and net reclassification improvement analysis (category-less net reclassification improvement 0.10 to 0.45). Although a diffuse CAC pattern was associated with worse outcomes in participants with ≥2 vessels with CAC (hazard ratio: 1.33 to 1.41; p < 0.05), adding this variable to the Agatston CAC score and number of vessels with CAC did not further improve global risk prediction.

CONCLUSIONS

The number of coronary arteries with calcified plaque, indicating increasingly "diffuse" multivessel subclinical atherosclerosis, adds significantly to the traditional Agatston CAC score for the prediction of CHD and CVD events.

Coronary Atherosclerotic Plaque Detected by Computed Tomographic Angiography in Subjects with Diabetes Compared to Those without Diabetes

OBJECTIVES

Little data are available regarding coronary plaque composition and semi-quantitative scores in individuals with diabetes; the extent to which diabetes may affect the presence and extent of Coronary Artery Calcium (CAC) needs more evaluation. Considering that this information may be of great value in formulating preventive interventions in this population, we compared these findings in individuals with diabetes to those without.

METHODS

Multi-Detector Computed Tomographic (MDCT) images of 861 consecutive patients with diabetes who were referred to Los Angeles Biomedical Research Institute from January 2000 to September 2012, were evaluated using a 15-coronary segment model. All 861 patients underwent calcium scoring and from these; 389 had coronary CT angiography (CTA). CAC score was compared to 861 age, sex and ethnicity matched controls without diabetes after adjustment for Body Mass Index (BMI), family history of coronary artery disease, hyperlipidemia, hypertension and smoking. Segment Involvement Score (SIS; the total number of segments with any plaque), Segment Stenosis Score (SSS; the sum of maximal stenosis score per segment), Total Plaque Score (TPS; the sum of the plaque amount per segment) and plaque compositionwere compared to 389 age, sex and ethnicity matched controls without diabetes after adjustment for BMI, family history of coronary artery disease, hyperlipidemia, hypertension and smoking.

RESULTS

Diabetes was positively correlated to the presence and extent of CAC (P<0.0001 for both). SIS, SSS and TPS were significantly higher in those with diabetes (P<0.0001). Number of mixed and calcified plaques were significantly higher in those with diabetes (P = 0.018 and P<0.001 respectively) but there was no significant difference in the number of non-calcified plaques between the two groups (P = 0.398).

CONCLUSIONS

Patients with diabetes have higher CAC and semi-quantitative coronary plaque scores compared to the age, gender and ethnicity matched controls without diabetes after adjustment for cardiovascular risk factors. Since mixed plaque is associated with worse long-term clinical outcomes, these findings support more aggressive preventive measures in this population.

Coronary artery calcium: 0.5 mm slice-thickness reconstruction with adjusted attenuation threshold outperforms 3.0 mm by validating against spatially registered intravascular ultrasound with radiofrequency backscatter

RATIONALE AND OBJECTIVES

Coronary artery calcium (CAC) images can be reconstructed with thinner slice thickness on some modern multidetector-row computed tomography scanners without additional radiation. We hypothesized that the isotropic 0.5-mm CAC reconstruction outperforms the conventional 3.0-mm reconstruction in detecting and quantifying coronary calcium, and we proposed to compare them by validating against spatially registered intravascular ultrasound with radiofrequency backscatter-virtual histology (IVUS-VH).

MATERIALS AND METHODS

Twenty-seven patients were enrolled, and 5976 mm of coronary arteries were analyzed. A semiautomatic software was developed to coregister CAC and IVUS-VH on a detailed slice-by-slice basis. Calcium detection and calcium volume quantification were evaluated and compared using varying calcium attenuation thresholds. Algorithms for deriving individualized optimal threshold and comparable Agatston score on the 0.5-mm reconstruction were developed.

RESULTS

The isotropic 0.5-mm reconstruction achieved significantly higher area under receiver-operating curve than the conventional 3.0-mm reconstruction (0.9 vs. 0.74, P < .001). Using the optimal threshold, the 0.5-mm reconstruction had higher sensitivity (0.79 vs. 0.65), specificity (0.85 vs. 0.77), positive predictive value (0.42 vs. 0.29), and negative predictive value (0.97 vs. 0.94) than the 3.0 mm. Individualized optimal threshold was significantly correlated with the image noise (r = 0.66, P < .001) in the 0.5-mm reconstruction.

CONCLUSIONS

By optimizing the calcium threshold, the 0.5-mm reconstruction is superior to the conventional 3.0-mm in detecting and quantifying calcium, which may improve the clinical value of CAC without additional radiation.

Role of computed tomography screening for detection of coronary artery disease

Coronary artery disease (CAD) is a leading cause of morbidity and mortality in Western populations, and the prediction and prevention of CAD is an inherent challenge facing current health care societies. Computed tomography (CT) has emerged as a noninvasive imaging tool in the field of cardiovascular disease. Notably, CT scanning for detection of coronary artery calcium (CAC) has proven useful in predicting adverse cardiovascular outcomes as well as early identification of CAD. In asymptomatic persons undergoing screening for CAD, CAC is well established as a surrogate of CAD risk and has demonstrated incremental benefit over and above traditional risk prediction tools. In addition, a zero CAC score has shown to reflect a substantially lower risk of CAD and may therefore be considered an important marker of CAD protection. Irrespective of screening in the asymptomatic population, CAC scanning has also displayed a beneficial role in the symptomatic population, specifically as gatekeeper in guiding further treatment decision making. Further still, the combination of alternative CT screening strategies such as CT screening for lung cancer with CAC scanning may hold particular promise as an effective screening approach by lowering overall health costs as well as limiting radiation exposure.

Coronary calcification in SLE: comparison with the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

Accelerated atherosclerosis is a major cause of morbidity and death in SLE. The purpose of this study was to determine whether the prevalence and extent of coronary artery calcium (CAC) is higher in female SLE patients compared with a non-SLE sample from the Multi-Ethnic Study of Atherosclerosis (MESA).

METHODS

CAC was measured in 80 female SLE patients and 241 female MESA controls from the Baltimore Field Centre, ages 45-64 years, without evidence of clinical cardiovascular disease. Binary regression was used to estimate the ratio of CAC prevalence in SLE vs MESA controls, controlling for demographic and cardiovascular risk factors. To compare the groups with respect to the quantity of CAC among those with non-zero Agatston scores, we used linear models in which the outcome was a log-transformed Agatston score.

RESULTS

The prevalence of CAC was substantially higher in SLE. The differences were most pronounced and statistically significant in those aged 45-54 years (58% vs 20%, P < 0.0001), but were still observed among those aged 55-65 years (57% vs 36%, P = 0.069). After controlling for age, ethnicity, education, income, diabetes mellitus, hypertension, hyperlipidaemia, high-density lipoprotein levels, smoking, education and BMI, SLE patients still had a significantly higher prevalence of CAC than controls. Among those with CAC, the mean log Agatston score did not differ significantly between SLE and MESA participants.

CONCLUSION

Women with SLE have a higher prevalence of CAC than comparable women without SLE, even after adjusting for traditional cardiovascular risk factors, especially among those aged 45-54 years.