Detection of Cardioembolic Sources With Nongated Cardiac Computed Tomography Angiography in Acute Stroke: Results From the ENCLOSE Study.

BACKGROUND: Identifying cardioembolic sources in patients with acute ischemic stroke is important for the choice of secondary prevention strategies. We prospectively investigated the yield of admission (spectral) nongated cardiac computed tomography angiography (CTA) to detect cardioembolic sources in stroke. METHODS: Participants of the ENCLOSE study (Improved Prediction of Recurrent Stroke and Detection of Small Volume Stroke) with transient ischemic attack or acute ischemic stroke with assessable nongated head-to-heart CTA at the University Medical Center Utrecht were included between June 2017 and March 2022. The presence of cardiac thrombus on cardiac CTA was based on a Likert scale and dichotomized into certainly or probably absent versus possibly, probably, or certainly present. The diagnostic certainty of cardiac thrombus was evaluated again on spectral computed tomography reconstructions. The likelihood of a cardioembolic source was determined post hoc by an expert panel in patients with cardiac thrombus on CTA. Parametric and nonparametric tests were used to compare the outcome groups. RESULTS: Forty four (12%) of 370 included patients had a cardiac thrombus on admission CTA: 35 (9%) in the left atrial appendage and 14 (4%) in the left ventricle. Patients with cardiac thrombus had more severe strokes (median National Institutes of Health Stroke Scale score, 10 versus 4; P=0.006), had higher clot burden (median clot burden score, 9 versus 10; P=0.004), and underwent endovascular treatment more often (43% versus 20%; P<0.001) than patients without cardiac thrombus. Left atrial appendage thrombus was present in 28% and 6% of the patients with and without atrial fibrillation, respectively (P<0.001). The diagnostic certainty for left atrial appendage thrombus was higher for spectral iodine maps compared with the conventional CTA (P<0.001). The presence of cardiac thrombus on CTA increased the likelihood of a cardioembolic source according to the expert panel (P<0.001). CONCLUSIONS: Extending the stroke CTA to cover the heart increases the chance of detecting cardiac thrombi and helps to identify cardioembolic sources in the acute stage of ischemic stroke with more certainty. Spectral iodine maps provide additional value for detecting left atrial appendage thrombus. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT04019483.

Determinants of 18F-NaF uptake in femoral arteries in patients with type 2 diabetes mellitus.

BACKGROUND: The goal of this study was to investigate the potential determinants of 18F-NaF uptake in femoral arteries as a marker of arterial calcification in patients with type 2 diabetes and a history of arterial disease. METHODS AND RESULTS: The study consisted of participants of a randomized controlled trial to investigate the effect of vitamin K2 (NCT02839044). In this prespecified analysis, subjects with type 2 diabetes and known arterial disease underwent full body 18F-NaF PET/CT. Target-to-background ratio (TBR) was calculated by dividing the mean SUVmax from both superficial femoral arteries by the SUVmean in the superior vena cava (SVC) and calcium mass was measured on CT. The association between 18F-NaF TBR and cardiovascular risk factors was investigated using uni- and multivariate linear regression corrected for age and sex. In total, 68 patients (mean age: 69 ± 8 years; male: 52) underwent 18F-NaF PET/CT. Higher CT calcium mass, total cholesterol, and HbA1c were associated with higher 18F-NaF TBR after adjusting. CONCLUSION: This study shows that several modifiable cardiovascular risk factors (total cholesterol, triglycerides, HbA1c) are associated with femoral 18F-NaF tracer uptake in patients with type 2 diabetes.

Prediction of long-term recurrent ischemic stroke: the added value of non-contrast CT, CT perfusion, and CT angiography.

PURPOSE: The aim of this study was to evaluate whether the addition of brain CT imaging data to a model incorporating clinical risk factors improves prediction of ischemic stroke recurrence over 5 years of follow-up. METHODS: A total of 638 patients with ischemic stroke from three centers were selected from the Dutch acute stroke study (DUST). CT-derived candidate predictors included findings on non-contrast CT, CT perfusion, and CT angiography. Five-year follow-up data were extracted from medical records. We developed a multivariable Cox regression model containing clinical predictors and an extended model including CT-derived predictors by applying backward elimination. We calculated net reclassification improvement and integrated discrimination improvement indices. Discrimination was evaluated with the optimism-corrected c-statistic and calibration with a calibration plot. RESULTS: During 5 years of follow-up, 56 patients (9%) had a recurrence. The c-statistic of the clinical model, which contained male sex, history of hyperlipidemia, and history of stroke or transient ischemic attack, was 0.61. Compared with the clinical model, the extended model, which contained previous cerebral infarcts on non-contrast CT and Alberta Stroke Program Early CT score greater than 7 on mean transit time maps derived from CT perfusion, had higher discriminative performance (c-statistic 0.65, P = 0.01). Inclusion of these CT variables led to a significant improvement in reclassification measures, by using the net reclassification improvement and integrated discrimination improvement indices. CONCLUSION: Data from CT imaging significantly improved the discriminatory performance and reclassification in predicting ischemic stroke recurrence beyond a model incorporating clinical risk factors only.

Signs of Pulmonary Infection on Admission Chest Computed Tomography Are Associated With Pneumonia or Death in Patients With Acute Stroke.

Background and Purpose- In patients with acute stroke, the occurrence of pneumonia has been associated with poor functional outcomes and an increased risk of death. We assessed the presence and consequences of signs of pulmonary infection on chest computed tomography (CT) before the development of clinically overt pneumonia. Methods- In 200 consecutive patients with acute ischemic stroke who had CT angiography from skull to diaphragm (including CT of the chest) within 24 hours of symptom onset, we assessed the presence of consolidation, ground-glass-opacity and the tree-in-bud sign as CT signs of pulmonary infection and assessed the association with the development of clinically overt pneumonia and death in the first 7 days and functional outcome after 90 days with logistic regression. Results- The median time from stroke onset to CT was 151 minutes (interquartile range, 84-372). Thirty patients (15%) had radiological signs of infection on admission, and 22 (11.0%) had a clinical diagnosis of pneumonia in the first 7 days. Patients with radiological signs of infection had a higher risk of developing clinically overt pneumonia (30% versus 7.6%; adjusted odds ratios, 4.2 [95% CI, 1.5-11.7]; P=0.006) and had a higher risk of death at 7 days (adjusted odds ratios, 3.7 [95% CI, 1.2-11.6]; P=0.02), but not at 90 days. Conclusions- About 1 in 7 patients with acute ischemic stroke had radiological signs of pulmonary infection within hours of stroke onset. These patients had a higher risk of clinically overt pneumonia or death. Early administration of antibiotics in these patients may lead to better outcomes.

Perivascular Epicardial Fat Stranding at Coronary CT Angiography: A Marker of Acute Plaque Rupture and Spontaneous Coronary Artery Dissection.

Purpose To evaluate the frequency and implications of perivascular fat stranding on coronary computed tomography (CT) angiograms obtained for suspected acute coronary syndrome (ACS). Materials and Methods This retrospective registry study was approved by the institutional review board. The authors reviewed the medical records and images of 1403 consecutive patients (796 men, 607 women; mean age, 52.8 years) who underwent coronary CT angiography at the emergency department from February 2012 to March 2016. Fat attenuation, length and number of circumferential quadrants of the affected segment, and attenuation values in the unaffected epicardial and subcutaneous fat were measured. "Cases" were defined as patients with perivascular fat stranding. Patients with significant stenosis but without fat stranding were considered control subjects. Baseline imaging characteristics, ACS frequency, and results of subsequent downstream testing were compared between cases and control subjects by using two-sample t, Mann-Whitney U, and Fisher tests. Results Perivascular fat stranding was seen in 11 subjects, nine with atherosclerotic lesions and two with spontaneous coronary artery dissections, with a mean fat stranding length of 19.2 mm and circumferential extent averaging 2.9 quadrants. The mean attenuation of perivascular fat stranding, normal epicardial fat, and normal subcutaneous fat was 17, -93.2, and -109.3 HU, respectively (P < .001). Significant differences (P < .05) between cases and control subjects included lower Agatston score, presence of wall motion abnormality, and initial elevation of serum troponin level. ACS frequency was 45.4% in cases and 3.8% in control subjects (P = .001). Conclusion Recognition of perivascular fat stranding may be a helpful additional predictor of culprit lesion and marker of risk for ACS in patients with significant stenosis or spontaneous coronary artery dissection. © RSNA, 2018 Online supplemental material is available for this article.

Imaging Atherosclerosis.

Advances in atherosclerosis imaging technology and research have provided a range of diagnostic tools to characterize high-risk plaque in vivo; however, these important vascular imaging methods additionally promise great scientific and translational applications beyond this quest. When combined with conventional anatomic- and hemodynamic-based assessments of disease severity, cross-sectional multimodal imaging incorporating molecular probes and other novel noninvasive techniques can add detailed interrogation of plaque composition, activity, and overall disease burden. In the catheterization laboratory, intravascular imaging provides unparalleled access to the world beneath the plaque surface, allowing tissue characterization and measurement of cap thickness with micrometer spatial resolution. Atherosclerosis imaging captures key data that reveal snapshots into underlying biology, which can test our understanding of fundamental research questions and shape our approach toward patient management. Imaging can also be used to quantify response to therapeutic interventions and ultimately help predict cardiovascular risk. Although there are undeniable barriers to clinical translation, many of these hold-ups might soon be surpassed by rapidly evolving innovations to improve image acquisition, coregistration, motion correction, and reduce radiation exposure. This article provides a comprehensive review of current and experimental atherosclerosis imaging methods and their uses in research and potential for translation to the clinic.

CT myocardial perfusion imaging: ready for prime time?

The detection of functional coronary artery stenosis with coronary CT angiography (CCTA) is suboptimal. Additional CT myocardial perfusion imaging (CT-MPI) may be helpful to identify patients with myocardial ischaemia in whom coronary revascularization therapy would be beneficial. CT-MPI adds incremental diagnostic and prognostic value over obstructive disease on CCTA. It allows for the quantitation of myocardial blood flow and calculation of coronary flow reserve and shows good correlation with 15O-H2O positron emission tomography and invasive fractional flow reserve. In addition, patients prefer CCTA/CT-MPI over SPECT, MRI and invasive coronary angiography. CT-MPI is ready for clinical use for detecting myocardial ischaemia caused by obstructive disease. Nevertheless, the clinical utility of CT-MPI to identify ischaemia in patients with non-obstructive/microvascular disease still has to be established. KEY POINTS: • CT-MPI can improve the positive predictive value of CCTA for lesion-specific ischaemia. • CT-MPI adds incremental prognostic value over CCTA for major adverse cardiac events. • CT-MPI correlates with 15 O-H 2 O PET. • CT-MPI/CCTA shows high overall patient satisfaction.

Clinical and Imaging Predictors of Recurrent Ischemic Stroke: A Systematic Review and Meta-Analysis.

BACKGROUND: Predictors of recurrent ischemic stroke are less well known in patients with a recent ischemic stroke than in patients with transient ischemic attack (TIA). We identified clinical and radiological factors for predicting recurrent ischemic stroke in patients with recent ischemic stroke. METHODS: A systematic search in PubMed, Embase, Cochrane Library, and CINAHL was performed with the terms "ischemic stroke," "predictors/determinants," and "recurrence." Quality assessment of the articles was performed and the level of evidence was graded for the articles included for the meta-analysis. Pooled risk ratios (RR) and heterogeneity (I2) were calculated using inverse variance random effects models. RESULTS: Ten articles with high-quality results were identified for meta-analysis. Past medical history of stroke or TIA was a predictor of recurrent ischemic stroke (pooled RR 2.5, 95% CI 2.1-3.1). Small vessel strokes were associated with a lower risk of recurrence than large vessel strokes (pooled RR 0.3, 95% CI 0.1-0.7). Patients with stroke of an undetermined cause had a lower risk of recurrence than patients with large artery atherosclerosis (pooled RR 0.5, 95% CI 0.2-1.1). We found no studies using CT or ultrasound for the prediction of recurrent ischemic stroke. The following MRI findings were predictors of recurrent ischemic stroke: multiple lesions (pooled RR 1.7, 95% CI 1.5-2.0), multiple stage lesions (pooled RR 4.1, 95% CI 3.1-5.5), multiple territory lesions (pooled RR 2.9, 95% CI 2.0-4.2), chronic infarcts (pooled RR 1.5, 95% CI 1.2-1.9), and isolated cortical lesions (pooled RR 2.2, 95% CI 1.5-3.2). CONCLUSIONS: In patients with a recent ischemic stroke, a history of stroke or TIA and the subtype large artery atherosclerosis are associated with an increased risk of recurrent ischemic stroke. Predictors evaluated with MRI include multiple ischemic changes and isolated cortical lesions. Predictors of recurrent ischemic stroke concerning CT or ultrasound have not been published.

PET Molecular Targets and Near-Infrared Fluorescence Imaging of Atherosclerosis.

PURPOSE OF REVIEW: With this review, we aim to summarize the role of positron emission tomography (PET) and near-infrared fluorescence imaging (NIRF) in the detection of atherosclerosis. RECENT FINDINGS: 18F-FDG is an established measure of increased macrophage activity. However, due to its low specificity, new radiotracers have emerged for more specific detection of vascular inflammation and other high-risk plaque features such as microcalcification and neovascularization. Novel NIRF probes are engineered to sense endothelial damage as an early sign of plaque erosion as well as oxidized low-density lipoprotein (oxLDL) as a prime target for atherosclerosis. Integrated NIRF/OCT (optical coherence tomography) catheters enable to detect stent-associated microthrombi. Novel radiotracers can improve specificity of PET for imaging atherosclerosis. Advanced NIRF probes show promise for future application in human. Intravascular NIRF might play a prominent role in the detection of stent-induced vascular injury.

Real-time fusion of coronary CT angiography with x-ray fluoroscopy during chronic total occlusion PCI.

OBJECTIVES: The purpose of this study was to demonstrate the feasibility of real-time fusion of coronary computed tomography angiography (CTA) centreline and arterial wall calcification with x-ray fluoroscopy during chronic total occlusion (CTO) percutaneous coronary intervention (PCI). METHODS: Patients undergoing CTO PCI were prospectively enrolled. Pre-procedural CT scans were integrated with conventional coronary fluoroscopy using prototype software. We enrolled 24 patients who underwent CTO PCI using the prototype CT fusion software, and 24 consecutive CTO PCI patients without CT guidance served as a control group. RESULTS: Mean age was 66 ± 11 years, and 43/48 patients were men. Real-time CTA fusion during CTO PCI provided additional information regarding coronary arterial calcification and tortuosity that generated new insights into antegrade wiring, antegrade dissection/reentry, and retrograde wiring during CTO PCI. Overall CTO success rates and procedural outcomes remained similar between the two groups, despite a trend toward higher complexity in the fusion CTA group. CONCLUSIONS: This study demonstrates that real-time automated co-registration of coronary CTA centreline and calcification onto live fluoroscopic images is feasible and provides new insights into CTO PCI, and in particular, antegrade dissection reentry-based CTO PCI. KEY POINTS: • Real-time semi-automated fusion of CTA/fluoroscopy is feasible during CTO PCI. • CTA fusion data can be toggled on/off as desired during CTO PCI • Real-time CT calcium and centreline overlay could benefit antegrade dissection/reentry-based CTO PCI.

Low-tube-voltage selection for triple-rule-out CTA: relation to patient size.

OBJECTIVES: To investigate the relationship between image quality and patient size at 100 kilovoltage (kV) compared to 120 kV ECG-gated Triple-Rule-Out CT angiography (TRO-CTA). METHODS: We retrospectively included 73 patients (age 64 ± 14 years) who underwent retrospective ECG-gated chest CTA. 40 patients were scanned with 100 kV while 33 patients with 120 kV. Body mass index (BMI), patients' chest circumference (PC) and thoracic surface area (TSA) were recorded. Quantitative image quality was assessed as vascular attenuation in the ascending aorta (AA), pulmonary trunk (PA) and left coronary artery (LCA) and the signal-to-noise ratio (SNR) in the AA. RESULTS: There was no significant difference in BMI (26.0 ± 4.6 vs. 28.0 ± 6.7 kg/m2), PC (103 ± 7 vs. 104 ± 10 cm2) and TSA (92 ± 15 vs. 91 ± 19 cm2) between 100 kV and 120 kV group. Mean vascular attenuation was significantly higher in the 100 kV compared to the 120 kV group (AA 438 vs. 354 HU, PA 460 vs. 349 HU, LCA 370 vs. 299 HU all p < 0.001). SNR was not significantly different, even after adjusting for patient size. Radiation dose was significantly lower in the 100 kV group (10.7 ± 4.1 vs. 20.7 ± 10.7 mSv; p < 0.001). CONCLUSIONS: 100 kV TRO-CTA is feasible in normal-to-overweight patients while maintaining image quality and achieving substantial dose reduction. KEY POINTS: • 100 kV protocols result in a significantly lower radiation dose. • Mean vascular attenuation is significantly higher using 100 kV. • SNR and CNR are not significantly different between 100 kV and 120 kV. • 100 kV CTA is feasible regardless of patient size while maintaining image quality.

Clinical implementation of an emergency department coronary computed tomographic angiography protocol for triage of patients with suspected acute coronary syndrome.

OBJECTIVES: To evaluate the efficiency and safety of emergency department (ED) coronary computed tomography angiography (CTA) during a 3-year clinical experience. METHODS: Single-center registry of coronary CTA in consecutive ED patients with suspicion of acute coronary syndrome (ACS). The primary outcome was efficiency of coronary CTA defined as the length of hospitalization. Secondary endpoints of safety were defined as the rate of downstream testing, normalcy rates of invasive coronary angiography (ICA), absence of missed ACS, and major adverse cardiac events (MACE) during follow-up, and index radiation exposure. RESULTS: One thousand twenty two consecutive patients were referred for clinical coronary CTA with suspicion of ACS. Overall, median time to discharge home was 10.5 (5.7-24.1) hours. Patient disposition was 42.7 % direct discharge from the ED, 43.2 % discharge from emergency unit, and 14.1 % hospital admission. ACS rate during index hospitalization was 9.1 %. One hundred ninety two patients underwent additional diagnostic imaging and 77 underwent ICA. The positive predictive value of CTA compared to ICA was 78.9 % (95 %-CI 68.1-87.5 %). Median CT radiation exposure was 4.0 (2.5-5.8) mSv. No ACS was missed; MACE at follow-up after negative CTA was 0.2 %. CONCLUSIONS: Coronary CTA in an experienced tertiary care setting allows for efficient and safe management of patients with suspicion for ACS. KEY POINTS: • ED Coronary CTA using advanced systems is associated with low radiation exposure. • Negative coronary CTA is associated with low rates of MACE. • CTA in ED patients enables short median time to discharge home. • CTA strategy is characterized by few downstream tests including unnecessary ICA.

Increased arterial inflammation in individuals with stage 3 chronic kidney disease.

PURPOSE: While it is well known that patients with chronic kidney disease (CKD) are at increased risk for the development and progression of atherosclerosis, it is not known whether arterial inflammation is increased in mild CKD. The aim of this study was to compare arterial inflammation using 18F-FDG PET/CT in patients with CKD and in matched controls. METHODS: This restrospective study included 128 patients undergoing FDG PET/CT imaging for clinical indications, comprising 64 patients with stage 3 CKD and 64 control patients matched by age, gender, and cancer history. CKD was defined according to guidelines using a calculated glomerular filtration rate (eGFR). Arterial inflammation was measured in the ascending aorta as FDG uptake on PET. Background FDG uptake (venous, subcutaneous fat and muscle) were recorded. Coronary artery calcification (CAC) was assessed using the CT images. The impact of CKD on arterial inflammation and CAC was then assessed. RESULTS: Arterial inflammation was higher in patients with CKD than in matched controls (standardized uptake value, SUV: 2.41 ± 0.49 vs. 2.16 ± 0.43; p = 0.002). Arterial SUV correlated inversely with eGFR (r = -0.299, p = 0.001). Venous SUV was also significantly elevated in patients with CKD, while subcutaneous fat and muscle tissue SUVs did not differ between groups. Moreover, arterial SUV remained significantly elevated in patients with CKD compared to controls after correcting for muscle and fat background, and also remained significant after adjusting for clinical risk factors. Further, CKD was associated with arterial inflammation (SUV) independent of the presence of subclinical atherosclerosis (CAC). CONCLUSION: Moderate CKD is associated with increased arterial inflammation beyond that of controls. Further, the increased arterial inflammation is independent of presence of subclinical atherosclerosis. Current risk stratification tools may underestimate the presence of atherosclerosis in patients with CKD and thereby the risk of cardiovascular events.

Inter-observer and inter-examination variability of manual vertebral bone attenuation measurements on computed tomography.

OBJECTIVE: To determine inter-observer and inter-examination variability of manual attenuation measurements of the vertebrae in low-dose unenhanced chest computed tomography (CT). METHODS: Three hundred and sixty-seven lung cancer screening trial participants who underwent baseline and repeat unenhanced low-dose CT after 3 months because of an indeterminate lung nodule were included. The CT attenuation value of the first lumbar vertebrae (L1) was measured in all CTs by one observer to obtain inter-examination reliability. Six observers performed measurements in 100 randomly selected CTs to determine agreement with limits of agreement and Bland-Altman plots and reliability with intraclass correlation coefficients (ICCs). Reclassification analyses were performed using a threshold of 110 HU to define osteoporosis. RESULTS: Inter-examination reliability was excellent with an ICC of 0.92 (p < 0.001). Inter-examination limits of agreement ranged from -26 to 28 HU with a mean difference of 1 ± 14 HU. Inter-observer reliability ICCs ranged from 0.70 to 0.91. Inter-examination variability led to 11.2 % reclassification of participants and inter-observer variability led to 22.1 % reclassification. CONCLUSIONS: Vertebral attenuation values can be manually quantified with good to excellent inter-examination and inter-observer reliability on unenhanced low-dose chest CT. This information is valuable for early detection of osteoporosis on low-dose chest CT. KEY POINTS: • Vertebral attenuation values can be manually quantified on low-dose unenhanced CT reliably. • Vertebral attenuation measurements may be helpful in detecting subclinical low bone density. • This could become of importance in the detection of osteoporosis.

Sublingual Nitroglycerin Administration in Coronary Computed Tomography Angiography: a Systematic Review.

OBJECTIVE: To systematically investigate the literature for the influence of sublingual nitroglycerin administration on coronary diameter, the number of evaluable segments, image quality, heart rate and blood pressure, and diagnostic accuracy of coronary computed tomography (CT) angiography. METHODS: A systematic search was performed in PubMed, EMBASE and Web of Science. The studies were evaluated for the effect of sublingual nitroglycerin on coronary artery diameter, evaluable segments, objective and subjective image quality, systemic physiological effects and diagnostic accuracy. Due to the heterogeneous reporting of outcome measures, a narrative synthesis was applied. RESULTS: Of the 217 studies identified, nine met the inclusion criteria: seven reported on the effect of nitroglycerin on coronary artery diameter, six on evaluable segments, four on image quality, five on systemic physiological effects and two on diagnostic accuracy. Sublingual nitroglycerin administration resulted in an improved evaluation of more coronary segments, in particular, in smaller coronary branches, better image quality and improved diagnostic accuracy. Side effects were mild and were alleviated without medical intervention. CONCLUSION: Sublingual nitroglycerin improves the coronary diameter, the number of assessable segments, image quality and diagnostic accuracy of coronary CT angiography without major side effects or systemic physiological changes. KEY POINTS: • Sublingual nitroglycerin administration results in significant coronary artery dilatation. • Nitroglycerin increases the number of evaluable coronary branches. • Image quality is improved the most in smaller coronary branches. • Nitroglycerin increases the diagnostic accuracy of coronary CT angiography. • Most side effects are mild and do not require medical intervention.

Pulmonary function and CT biomarkers as risk factors for cardiovascular events in male lung cancer screening participants: the NELSON study.

OBJECTIVE: The objective of this study was to investigate the association of spirometry and pulmonary CT biomarkers with cardiovascular events. METHODS: In this lung cancer screening trial 3,080 male participants without a prior cardiovascular event were analysed. Fatal and non-fatal cardiovascular events were included. Spirometry included forced expiratory volume measured in units of one-second percent predicted (FEV1%predicted) and FEV1 divided by forced vital capacity (FVC; FEV1/FVC). CT examinations were quantified for coronary artery calcium volume, pulmonary emphysema (perc15) and bronchial wall thickness (pi10). Data were analysed via a Cox proportional hazard analysis, net reclassification improvement (NRI) and C-indices. RESULTS: 184 participants experienced a cardiovascular event during a median follow-up of 2.9 years. Age, pack-years and smoking status adjusted hazard ratios were 0.992 (95% confidence interval (CI) 0.985-0.999) for FEV1%predicted, 1.000 (95%CI 0.986-1.015) for FEV1/FVC, 1.014 (95%CI 1.005-1.023) for perc15 per 10 HU, and 1.269 (95%CI 1.024-1.573) for pi10 per 1 mm. The incremental C-index (<0.015) and NRI (<2.8%) were minimal. Coronary artery calcium volume had a hazard ratio of 1.046 (95%CI 1.034-1.058) per 100 mm(3), an increase in C-index of 0.076 and an NRI of 16.9% (P < 0.0001). CONCLUSIONS: Pulmonary CT biomarkers and spirometry measurements were significantly associated with cardiovascular events, but did not contain clinically relevant independent prognostic information for cardiovascular events. KEY POINTS: • Pulmonary CT biomarkers and spirometry are associated with cardiovascular events • These pulmonary measurements do not contain clinically relevant independent prognostic information • Only coronary calcium score improved cardiovascular risk prediction above age and smoking.

Coronary artery calcification scoring with state-of-the-art CT scanners from different vendors has substantial effect on risk classification.

PURPOSE: To determine the intervendor variability of Agatston scoring determined with state-of-the-art computed tomographic (CT) systems from the four major vendors in an ex vivo setup and to simulate the subsequent effects on cardiovascular risk reclassification in a large population-based cohort. MATERIALS AND METHODS: Research ethics board approval was not necessary because cadaveric hearts from individuals who donated their bodies to science were used. Agatston scores obtained with CT scanners from four different vendors were compared. Fifteen ex vivo human hearts were placed in a phantom resembling an average human adult. Hearts were scanned at equal radiation dose settings for the systems of all four vendors. Agatston scores were quantified semiautomatically with software used clinically. The ex vivo Agatston scores were used to simulate the effects of different CT scanners on reclassification of 432 individuals aged 55 years or older from a population-based study who were at intermediate cardiovascular risk based on Framingham risk scores. The Friedman test was used to evaluate overall differences, and post hoc analyses were performed by using the Wilcoxon signed-rank test with Bonferroni correction. RESULTS: Agatston scores differed substantially when CT scanners from different vendors were used, with median Agatston scores ranging from 332 (interquartile range, 114-1135) to 469 (interquartile range, 183-1381; P < .05). Simulation showed that these differences resulted in a change in cardiovascular risk classification in 0.5%-6.5% of individuals at intermediate risk when a CT scanner from a different vendor was used. CONCLUSION: Among individuals at intermediate cardiovascular risk, state-of the-art CT scanners made by different vendors produced substantially different Agatston scores, which can result in reclassification of patients to the high- or low-risk categories in up to 6.5% of cases.

The impact of CT radiation dose reduction and iterative reconstruction algorithms from four different vendors on coronary calcium scoring.

OBJECTIVES: To analyse the effects of radiation dose reduction and iterative reconstruction (IR) algorithms on coronary calcium scoring (CCS). METHODS: Fifteen ex vivo human hearts were examined in an anthropomorphic chest phantom using computed tomography (CT) systems from four vendors and examined at four dose levels using unenhanced prospectively ECG-triggered protocols. Tube voltage was 120 kV and tube current differed between protocols. CT data were reconstructed with filtered back projection (FBP) and reduced dose CT data with IR. CCS was quantified with Agatston scores, calcification mass and calcification volume. Differences were analysed with the Friedman test. RESULTS: Fourteen hearts showed coronary calcifications. Dose reduction with FBP did not significantly change Agatston scores, calcification volumes and calcification masses (P > 0.05). Maximum differences in Agatston scores were 76, 26, 51 and 161 units, in calcification volume 97, 27, 42 and 162 mm(3), and in calcification mass 23, 23, 20 and 48 mg, respectively. IR resulted in a trend towards lower Agatston scores and calcification volumes with significant differences for one vendor (P < 0.05). Median relative differences between reference FBP and reduced dose IR for Agatston scores remained within 2.0-4.6%, 1.0-5.3%, 1.2-7.7% and 2.6-4.5%, for calcification volumes within 2.4-3.9%, 1.0-5.6%, 1.1-6.4% and 3.7-4.7%, for calcification masses within 1.9-4.1%, 0.9-7.8%, 2.9-4.7% and 2.5-3.9%, respectively. IR resulted in increased, decreased or similar calcification masses. CONCLUSIONS: CCS derived from standard FBP acquisitions was not affected by radiation dose reductions up to 80%. IR resulted in a trend towards lower Agatston scores and calcification volumes. KEY POINTS: In this ex vivo study, radiation dose could be reduced by 80% for coronary calcium scoring. Iterative reconstruction resulted in a trend towards lower Agatston scores and calcification volumes. Caution should be taken for coronary calcium scoring with iterative reconstruction.

Cardiac valve calcifications on low-dose unenhanced ungated chest computed tomography: inter-observer and inter-examination reliability, agreement and variability.

OBJECTIVES: To determine inter-observer and inter-examination variability for aortic valve calcification (AVC) and mitral valve and annulus calcification (MC) in low-dose unenhanced ungated lung cancer screening chest computed tomography (CT). METHODS: We included 578 lung cancer screening trial participants who were examined by CT twice within 3 months to follow indeterminate pulmonary nodules. On these CTs, AVC and MC were measured in cubic millimetres. One hundred CTs were examined by five observers to determine the inter-observer variability. Reliability was assessed by kappa statistics (κ) and intra-class correlation coefficients (ICCs). Variability was expressed as the mean difference ± standard deviation (SD). RESULTS: Inter-examination reliability was excellent for AVC (κ = 0.94, ICC = 0.96) and MC (κ = 0.95, ICC = 0.90). Inter-examination variability was 12.7 ± 118.2 mm(3) for AVC and 31.5 ± 219.2 mm(3) for MC. Inter-observer reliability ranged from κ = 0.68 to κ = 0.92 for AVC and from κ = 0.20 to κ = 0.66 for MC. Inter-observer ICC was 0.94 for AVC and ranged from 0.56 to 0.97 for MC. Inter-observer variability ranged from -30.5 ± 252.0 mm(3) to 84.0 ± 240.5 mm(3) for AVC and from -95.2 ± 210.0 mm(3) to 303.7 ± 501.6 mm(3) for MC. CONCLUSIONS: AVC can be quantified with excellent reliability on ungated unenhanced low-dose chest CT, but manual detection of MC can be subject to substantial inter-observer variability. Lung cancer screening CT may be used for detection and quantification of cardiac valve calcifications. KEY POINTS: • Low-dose unenhanced ungated chest computed tomography can detect cardiac valve calcifications. • However, calcified cardiac valves are not reported by most radiologists. • Inter-observer and inter-examination variability of aortic valve calcifications is sufficient for longitudinal studies. • Volumetric measurement variability of mitral valve and annulus calcifications is substantial.