Modified Agatston Score Research Articles

Intracranial arterial calcification in patients with unruptured and ruptured intracranial aneurysms.

Arterial calcification is thought to protect against rupture of intracranial aneurysms, but studies in a representative population of intracranial aneurysm patients have not yet been performed. The aim was to compare the prevalence of aneurysm wall calcification and intracranial carotid artery calcification (ICAC) between patients with an unruptured intracranial aneurysm (UIA) and a ruptured intracranial aneurysm (RIA). We matched 150 consecutive UIA patients to 150 RIA patients on age and sex. Aneurysm wall calcification and ICAC were quantified on non-contrast enhanced computed tomography images with the modified Agatston score. We compared the prevalence of aneurysm wall calcification, ICAC, and severe ICAC (defined as a modified Agatston score in the fourth quartile) between UIA and RIA patients using univariate and multivariate conditional logistic regression models adjusted for aneurysm characteristics and cardiovascular risk factors. Aneurysm wall calcification was more prevalent in UIA compared to RIA patients (OR 5.2, 95% CI: 2.0-13.8), which persisted after adjustment (OR 5.9, 95% CI: 1.7-20.2). ICAC prevalence did not differ between the two groups (crude OR 0.9, 95% CI: 0.5-1.8). Severe ICAC was more prevalent in UIA patients (OR 2.0, 95% CI: 1.1-3.6), but not after adjustment (OR 1.0, 95% CI: 0.5-2.3). Aneurysm wall calcification but not ICAC was more prevalent in UIAs than in RIAs, which corresponds to the hypothesis that calcification may protect against aneurysmal rupture. Aneurysm wall calcification should be further assessed as a predictor of aneurysm stability in prospective cohort studies. Calcification of the intracranial aneurysm wall was more prevalent in unruptured than ruptured intracranial aneurysms after adjustment for cardiovascular risk factors. Calcification may therefore protect the aneurysm against rupture, and aneurysm wall calcification is a candidate predictor of aneurysm stability. Aneurysm wall calcification was more prevalent in patients with unruptured than ruptured aneurysms, while internal carotid artery calcification was similar. Aneurysm wall calcification but not internal carotid artery calcification is a candidate predictor of aneurysm stability. Cohort studies are needed to assess the predictive value of aneurysm wall calcification for aneurysm stability.

Ipsilateral Aorto-Iliac Calcification is Not Directly Associated With eGFR After Kidney Transplantation: A Prospective Cohort Study Analyzed Using a Linear Mixed Model.

Aorto-iliac calcification (AIC) is a well-studied risk factor for post-transplant cardiovascular events and mortality. Its effect on graft function remains unknown. The primary aim of this prospective cohort study was to assess the association between AIC and estimated glomerular filtration rate (eGFR) in the first year post-transplant. Eligibility criteria were: ≥50years of age or ≥30years with at least one risk factor for vascular disease. A non-contrast-enhanced CT-scan was performed with quantification of AIC using the modified Agatston score. The association between AIC and eGFR was investigated with a linear mixed model adjusted for predefined variables. One-hundred-and-forty patients were included with a median of 31 (interquartile range 26-39) eGFR measurements per patient. No direct association between AIC and eGFR was found. We observed a significant interaction between follow-up time and ipsilateral AIC, indicating that patients with higher AIC scores had lower eGFR trajectory over time starting 100days after transplant (p = 0.014). To conclude, severe AIC is not directly associated with lower post-transplant eGFR. The significant interaction indicates that patients with more severe AIC have a lower eGFR trajectory after 100days in the first year post-transplant.

Intraplaque calcium and its relation with the progression of carotid atheromatous disease.

Calcification and progression of atheromatous disease (AD) both have been independently related with the risk of stroke. However, the link between the two phenomena is still unclear. The main objective of this study was to analyze the temporal evolution of Ca content of carotid atheromatous plaques and its relation with the progression of carotid AD using quantitative CT Angiography (CTA). Forty-three asymptomatic patients with stenosis of the internal carotid artery (ICA)>50% completed the study. Contrast mold volume and calcium (Ca) content by quantitative CTA and Modified Agatston Score (Ca volume × radiological density) were assessed at baseline and after 12±2 months. Biochemical parameters, including main markers of Ca/Phosphorus (P) metabolism, were determined. CTA measurement showed an increase of volumetric stenosis (volume decrease of the contrast mold), compared to baseline (475.45 [155.6] mm3 × U.H vs. 501.3 [171.9] mm3 × U.H; P=0.04) as well as an increase of intraplaque Ca (64.58 [57.8] mm3 × U.H. vs. 56.8 [52.3] P=0.002). An inverse correlation between baseline Ca content and volumetric stenosis progression (r=-0.481; P<0.001), as well as between the increase of carotid Ca and plasma levels of vitamin D (r=0.4; P=0.025) were also found. Multiple regression analysis found a model with baseline intraplaque Ca, adjusted by Body Mass Index (BMI) as most predictive of carotid AD progression. These results suggest that a higher content of Ca confers greater stability against the progression of carotid AD and, eventually, its ability to generate symptomatology.

ABDOMINAL AORTA CALCIFICATION PRIOR TO KIDNEY TRANSPLANTATION: THE ASSOCIATION WITH PATIENT AND GRAFT SURVIVAL

Dutch Kidney Transplant Study Group. Introduction: A high degree of vascular calcification is commonly encountered in patients undergoing kidney transplantation, especially in those who were on long-term hemodialysis. The prognostic value of pre-transplant vascular calcification for patient and graft survival is unclear. Therefore, this study focused on the association of abdominal aortic calcification (AAC) prior to kidney transplantation and both all-cause mortality and graft failure. Materials and Methods: From 2005 to 2018, renal transplant recipients referred for a nonenhanced CT procedure within 3 years prior to kidney transplantation, were included in a dual-centre study. Primary endpoints were all-cause mortality and graft failure after kidney transplantation. AAC was retrospectively quantified using a semiautomated tool, as a modified Agatston score. Patients were stratified into three groups based on the AAC quantification results. A Kaplan-Meier curve, with Log Rank analysis, and a Cox proportional hazards model were used for time-to-event analysis. Multivariate analysis included the AAC score in quartiles, recipient age, sex and Body Mass Index (BMI) at moment of transplantation, duration of dialysis prior to transplantation and history of smoking. Results: We evaluated 547 patients, 461 (84.3%) had detectable calcifications and the median time between CT and transplantation was 1.0 (IQR 0.5 – 1.4) years. Sixty-nine (12.6%) patients died and 84 (15.4%) had graft failure during a median follow-up of 2.5 (IQR 1.0 – 4.3) years. Kaplan-Meier curves indicate that a higher AAC score was associated with a higher all-cause mortality (p < 0.001) (Figure 1.) and higher rate of graft failure (p = 0.009) (Figure 2.). Similarly, in univariate Cox proportional hazard analysis a high AAC score was associated with a higher all-cause mortality (HR 4.3 (95% CI 2.2 – 8.4, p < 0.001) and a higher rate of graft failure (HR 2.1 (95% CI 1.3 – 3.6, p < 0.004). These associations remained significant upon multivariate analysis, with HR 3.1 (95% CI 1.3 – 7.0), p = 0.008) and (HR 2.0 (95% CI 1.2 – 3.5, p < 0.00) for mortality and graft failure, respectively. Fig. 1.Fig. 2.Conclusion: A significant association between the degree of AAC, assessed by nonenhanced CT-based quantification, and both all-cause mortality and graft failure was identified. A validated scoring system for AAC could guide clinicians in decision-making with regard to risk stratification and expected patient-related outcomes after kidney transplantation.

P3382Vascular calcium Index: an imaging tool to predict vascular complications and major bleeding in TF-TAVI

Abstract Introduction Vascular calcification has been associated with worse outcomes in transfemoral TAVI (TF-TAVI). However, there is currently no simple method to assess it and identify different patterns of calcification in an objective and quantitative manner. The purpose of this study was to develop a quantitative score of aortic (Ao) and ileofemural (IF) calcification and to assess its ability to predict life-threatening bleeding (LTB) and major vascular complications during TF-TAVI. Methods Case-control single center retrospective study of patients undergoing TF-TAVI between Nov2015 and Aug2018 including 183 consecutive patients (99 women, mean age 83±3 years, mean Euroscore II - ESII - 6.0±4.1). The Vascular Calcium Score was calculated for the entire Ao and IF vessels using a modified Agatston score derived from contrast-enhanced CT images, with calcium threshold locally adjusted for luminal attenuation (mean attenuation + 5x SD). A luminal attenuation threshold &gt;600UH impaired vascular calcium evaluation and patients were excluded. LTB and major vascular complications were adjudicated according to the VARC-2 classification and identified by chart review by and independent team. Results Thirty patients (16%) suffered major bleeding and 13 (7%) experienced LTB. Major vascular injury occurred in 11 patients (6%). The median total vascular calcium score (TCS) was 11752 AU (IQR: 6388–19844) and median IF score (IFS) was 2210AU (IQR: 865–4170). TCS indexed for body surface area (TCSi) was predictor of LTB (AUC: 0.78±0.07, p&lt;0.05) and of major vascular complications (AUC: 0.85±0.05, p&lt;0.05). After multivariate analysis, iTCS and glomerular filtration rate (GFR) remained as predictors of LTB with an HR of 1.11 for each increase in 1000UA/m2 of TCSi (95% CI: 1.03–1.18) and 0.94 (95% CI: 0.88–0.985) respectively, independently of the ESII. iTCS and GFR were also independently associated with major vascular complications (p&lt;0.05). Patients with an iTCS above 9750AU/m2 have an odds ratio of 7.7 (95% CI: 2.0 - 29.2) for LTB. This cut-off has a sensitivity of 77% and a specificity of 70% for LTB. Similarly, patients with an iTCS above 9750AU/m2 have an odds ratio of 10.3 (95% CI: 22 - 49.3) for major vascular injury. Conclusions A quantitative score for vascular calcification in contrast-enhanced CT images was developed. iTCS was independently associated with life-threatening bleeding and major vascular complications.

Does Nonenhanced CT-based Quantification of Abdominal Aortic Calcification Outperform the Framingham Risk Score in Predicting Cardiovascular Events in Asymptomatic Adults?

Purpose To determine if abdominal aortic calcification (AAC) at CT predicts cardiovascular events independent of Framingham risk score (FRS). Materials and Methods For this retrospective study, electronic health records for 829 asymptomatic patients (mean age, 57.9 years; 451 women, 378 men) who underwent nonenhanced CT colonography screening between April 2004 and March 2005 were reviewed for subsequent cardiovascular events; mean follow-up interval was 11.2 years ± 2.8 (standard deviation). Institutional review board approval was obtained. CT-based AAC was retrospectively quantified as a modified Agatston score by using a semiautomated tool. Kaplan-Meier curves and Cox proportional hazards models were used for time-to-event analysis; receiver operating characteristic curves and net reclassification improvement compared predictive abilities of AAC and FRS. Results An index cardiovascular event occurred after CT in 156 (19%) of 829 patients (6.7 years ± 3.5, including heart attack in 39 [5%] and death in 79 [10%]). AAC was higher in the cardiovascular event cohort (mean AAC, 3478 vs 664; P < .001). AAC was a strong predictor of cardiovascular events at both univariable and multivariable Cox modeling, independent of FRS (P < .001). Kaplan-Meier plots showed better separation with AAC over FRS. The area under the receiver operating characteristic curve (AUC) was higher for AAC than FRS at all evaluated time points (eg, AUC of 0.82 vs 0.64 at 2 years; P = .014). By using a cutoff point of 200, AAC improved FRS risk categorization with net reclassification improvement of 35.4%. Conclusion CT-based abdominal aortic calcification was a strong predictor of future cardiovascular events, outperforming the Framingham risk score. This finding suggests a potential opportunistic role in abdominal nonenhanced CT scans performed for other clinical indications. © RSNA, 2018.

Association Between Abdominal Visceral Artery Calcification and All-Cause Mortality-A Computerized Tomography Imaging-Based Longitudinal Follow-Up Study.

Arterial calcification in different arterial beds has been observed to be an independent predictor of mortality. The association of abdominal visceral artery calcium with all-cause mortality remains unexplored. Patients who had undergone contrast-enhanced computerized tomography (CT) imaging for routine assessment of peripheral arterial disease (PAD) were considered for this study. A novel calcium score (abdominal visceral arteries calcium [AVAC]) for the abdominal visceral arteries (celiac axis, superior mesenteric, and renal arteries) was calculated using a modified Agatston score. Cumulative AVAC was defined as sum total of the calcium score of above individual arteries. The primary outcome was all-cause mortality. The association of AVAC with all-cause mortality was assessed. Of the 134 consecutive patients, 89 were included for analysis. Median follow-up duration was 72 (47-91) months since CT imaging; 35 (39%) patients died during this period. Hypertension and cumulative AVAC score had a significant association with all-cause mortality (P < .05). Cumulative visceral abdominal artery calcification is associated with all-cause mortality in patients with PAD. Future prospective studies are warranted to investigate this relationship in PAD and other patient cohorts.

Arteriosclerosis Is a Major Predictor of Small Bowel Vascular Lesions.

Most studies have focused on evaluating the association between the presence of small bowel vascular lesions (SBVLs) and patients' comorbidities. We sought to uncover a more fundamental indicator that may predict the presence of SBVLs by considering atherosclerosis qualitatively and quantitatively. We enrolled 79 consecutive patients with obscure gastrointestinal bleeding who had undergone computed tomography (CT) and capsule endoscopy or double-balloon endoscopy from January 2015 to June 2017. The SBVL frequency, type, and location, and the relationship between the presence of SBVLs and the patients' clinical characteristics were evaluated. Arterial wall calcification was assessed on unenhanced CT images, and a modified Agatston scoring system was used to determine the abdominal aorta calcium scores. Of the 27 (34%) patients with SBVLs, 15 (19%) had type 1a, 12 (15%) had type 1b, and 2 (3%) had type 2a SBVLs. Most of the lesions were located in the jejunum. Cardiovascular disease (P=.017), chronic kidney disease (P=.025), and arteriosclerosis (P=.0036) were associated with the presence of SBVLs. Subsequent multivariate analysis revealed that arteriosclerosis (odds ratio [OR] 7.29; 95% confidence interval [CI] 1.13-143.9) and superior mesenteric artery calcification (OR 16.3; 95% CI 3.64-118.6) were independent predictors of the presence of SBVLs. The modified Agatston score was significantly higher in SBVL cases than in non-SBVL cases (6384 vs. 2666, P=.0023). Arteriosclerosis, especially increased superior mesenteric artery calcification, is associated with an increased likelihood of SBVLs.

Editor's Choice – Calcification of Thoracic and Abdominal Aneurysms is Associated with Mortality and Morbidity

IntroductionCardiovascular events are common in people with aortic aneurysms. Arterial calcification is a recognised predictor of cardiovascular outcomes in coronary artery disease. Whether calcification within abdominal and thoracic aneurysm walls is correlated with poor cardiovascular outcomes is not known.Patients and methodsCalcium scores were derived from computed tomography (CT) scans of consecutive patients with either infrarenal (AAA) or descending thoracic aneurysms (TAA) using the modified Agatston score. The primary outcome was subsequent all cause mortality during follow-up. Secondary outcomes were cardiovascular mortality and morbidity.ResultsA total of 319 patients (123 TAA and 196 AAA; median age 77 [71–84] years, 72% male) were included with a median follow-up of 30 months. The primary outcome occurred in 120 (37.6%) patients. In the abdominal aortic aneurysm group, the calcium score was significantly related to both all cause mortality and cardiac mortality (odds ratios (OR) of 2.246 (95% CI 1.591–9.476; p < 0.001) and 1.321 (1.076–2.762; p = 0.003)) respectively. In the thoracic aneurysm group, calcium score was significantly related to all cause mortality (OR 6.444; 95% CI 2.574–6.137; p < 0.001), cardiac mortality (OR 3.456; 95% CI 1.765–4.654; p = 0.042) and cardiac morbidity (OR 2.128; 95% CI 1.973–4.342; p = 0.002).ConclusionsAortic aneurysm calcification, in either the thoracic or the abdominal territory, is significantly associated with both higher overall and cardiovascular mortality. Calcium scoring, rapidly derived from routine CT scans, may help identify high risk patients for treatment to reduce risk.

Multi-modality Imaging of Inflammation and Calcification within the Lower Limb Arterial Tree: A PET/CT Study

Atherosclerosis is linked with both inflammatory and calcific processes occurring at the vessel wall. Novel imaging techniques (PET CT analysis) have been developed to assess such processes using 18F-sodium fluoride (18F-NaF – calcification) and 18F-fluorodeoxyglucose (18F-FDG – inflammation). Such imaging has been predominantly undertaken within the coronary and carotid circulation. This study is the first to prospectively validate PET CT analysis in peripheral arterial disease (PAD). 8 patients (16 legs; 5 men, median age 74.5 years) with intermittent claudication underwent PET CT analysis using the 18F-NaF and 18F-FDG tracers using standard protocols. For each scan, the lower limb arterial tree was examined from the aortic bifurcation to the ankle. The degree of arterial calcification (AC) was measured using the modified Agatston score. Atherosclerotic disease burden was analysed using Bollinger scoring method. Overall whole limb median (IQR) TBR levels for 18F NaF was 1.30 (0.98–1.74) and for 18F FDG was 1.42 (1.11–1.75). The median limb AC score was 1954.5 (1198–2216). Significant correlations were seen between FDG uptake and both NaF uptake and AC and there was an inverse relationship between NaF tracer uptake and AC (all p < 0.05). Increasing burden of atherosclerosis was associated with lower NaF uptake and a higher AC (p < 0.05). This study is the first to validate PET CT analysis in patients with PAD. It also starts to assess potential relationships between inflammation and calcification. Further studies are required to look at longer-term consequence of such findings with regard to atherosclerotic progression/development.

208 Arterial Inflammation and Calcification in Patients with Lower Limb Atherosclerosis using PET/CT Analysis: A Proof-of-Principle Study

<h3>Introduction</h3> Lower limb peripheral arterial disease (PAD) is common. Atherosclerotic development is linked with inflammatory and calcific processes occurring at the vessel wall, having been evaluated in the coronary and carotid circulation using PET/CT analysis with the 18F FDG (inflammation) and 18F NaF (calcification) tracers. <h3>Methods</h3> 8 patients (16 legs; 5 men, median age 74.5 years; IQR (69.5–77.5)) with a diagnosis of intermittent claudication were prospectively recruited to the study. PET/CT analysis was undertaken in each patient using both tracers. The lower limb arterial tree was examined from the aortic bifurcation to the ankle. The degree of arterial calcification (AC) was measured using a modified Agatston score. Arterial 18F-NaF and 18F-FDG uptake was determined using standard protocols and measured by drawing regions of interest and normalised to tracer levels in the common femoral vein to obtain the arterial target-to-background ratio (TBR). Correlation between tracer uptake and AC was determined using Pearson’s correlation. <h3>Results</h3> The overall whole limb median (IQR) TBR levels for 18F NaF was 1.30 (0.98–1.74) and for 18F FDG was 1.42 (1.11–1.75). The median limb AC score was 1954.5 (1198–3216). A positive correlation was observed when arterial 18F FDG uptake was correlated with 18F NaF uptake (p = 0.000, r = 0.611) and AC score (p = 0.009, r = 0.654). An inverse correlation was found when correlating 18F NaF tracer uptake with AC score (p = 0.004, r=–0.765). <h3>Conclusion</h3> Lower limb disease progression will lead to increased atherosclerotic burden with a potential risk of amputation. This study is the first to determine the inter-relationship between inflammation and calcification within the lower limb arterial tree. Further studies are required to look at longer-term sequelae of atherosclerotic progression/development.

Abstract P175: Maintaining Ideal Cardiovascular Health and Freedom From Coronary Artery Calcification

Introduction: Ideal cardiovascular health (CVH), as defined by American Heart Association (AHA), is associated with low levels of cardiovascular disease (CVD) risk factors and freedom from coronary artery calcium (CAC). Hypothesis: Baseline ideal CVH predicts freedom from CAC progression. Methods: In the Framingham Heart Study (FHS), we evaluated prevalence of ideal CVH and investigated associations between ideal CVH and CAC progression. We included 1969 participants who attended the first and second rounds of the FHS Multi-Detector Computed Tomography study (MDCT-I and MDCT-II). The presence and burden of calcification was defined by a modified Agatston score. We calculated the repeatability of two CAC readings performed during MDCT-I and quantified the uncertainty estimate to define CAC progression. At follow-up, an increase in CAC score of 3.4 or higher was defined as positive CAC progression for those free of CAC at baseline. Using criteria modified from the AHA’s Strategic Impact Goal, we defined the prevalence of poor, intermediate and ideal CVH using five of the seven metrics: blood pressure, total-cholesterol, cigarette smoking, body mass index, and fasting glucose. For each metric of CVH, we assigned a score of 0, 1, and 2 points for poor, intermediate, and ideal CVH, respectively, to quantify CVH and extent of change in ideal CVH. Baseline age, baseline CVH status, and change in CVH category were independent variables for logistic regression models to test significant associations between CAC progression and change in ideal CVH. Results: The prevalence of ideal, intermediate, and poor CVH for 1148 participants who were free of baseline CAC were 15.77%, 43.73%, 40.51%, respectively. After an average 6.1 years of follow-up, the prevalence of ideal, intermediate, and poor CVH changed to 6.5%, 43.4%, and 50.1%, respectively, while the CAC progression rates were 8.0%, 13.1%, and 21.6%, respectively. In logistic regression models, there was a non-significant trend for CAC progression by CVH group. Compared to those with poor CVH at baseline, the presence of ideal CVH at baseline was significantly protective against the occurrence of CAC progression; the hazard ratio (HR) for occurrence of CAC progression was 0.36 (95%C.I. 0.19, 0.66, p&lt;0.001). Compared to those with intermediate CVH, there was potential protection against CAC progression, although the HR 0.66 was not statistically significant (95%C.I. 0.36, 1.21, p=0.62). Conclusions: In a community-based study, we observed significant protection from progression of CAC at follow-up for participants who were free of CAC with ideal CVH at baseline. These findings support continued public health measures to promote ideal CVH.

Quantification of coronary artery calcium in nongated CT to predict cardiovascular events in male lung cancer screening participants: Results of the NELSON study

ObjectiveTo evaluate the incremental prognostic value of the number and maximum volume of coronary artery calcifications over modified Agatston score strata, age, pack-years, and smoking status for predicting cardiovascular events. MethodsA total of 3559 male current and former smokers received a CT examination for lung cancer screening. Smoking characteristics, patient demographics, and physician-diagnosed cardiovascular events were collected. Images were acquired without electrocardiography gating on 16-slice CT scanners. The association between the presence of both fatal and nonfatal cardiovascular events and the predictors was quantified using Cox proportional hazard analysis. ResultsMedian follow-up period was 2.9 years. Incident cardiovascular events occurred in 186 participants. Adjusted hazard ratios for modified Agatston score strata of 1 to 10, 11 to 100, 101 to 400, and >400 were 3.39 (95% confidence interval [CI], 1.20–9.59), 6.52 (95% CI, 2.73–15.60), 6.58 (95% CI, 2.75–15.78), and 12.58 (95% CI, 5.42–29.16), respectively. Moreover, comparing the models with and without modified Agatston score strata to the model with age, pack-years, and smoking status yielded a significantly better net reclassification improvement (NRI; 27.3%; P < .0001). Adding the number of calcifications to the model with age, pack-years, smoking status, and modified Agatston score strata resulted in a slightly better NRI (1.68%; P = .0490) with a hazard ratio of 1.13 (95% CI, 1.05–1.21) per 10 calcifications. The incremental prognostic information contained in the volume of the largest calcification was not statistically significant (NRI, 0.14%; P = .3458). ConclusionCardiovascular event rate increased with higher numbers of calcified lesions. The number but not maximum volume of calcifications has independent, although minimal, prognostic value over age, pack-years, smoking status, and modified Agatston score strata in our population.

Distribution of Abdominal Aortic Calcium by Computed Tomography: Impact of Analysis Method on Quantitative Calcium Score

Abdominal aortic calcification (AAC) can be quantified using computed tomography (CT), but imaging planesare prescribed based on bony landmarks, so that individual variation between the landmark and the aortoiliac junction can result in variable aortic coverage. In the Framingham CT substudy, we scanned a 15-cm (Z-direction) abdominal segment cranial to the S1 vertebral body. We sought to determine the range and distribution of length of aorta scanned and the distribution of AAC within the abdominal aorta and to compare burden of AAC measured from fixed-length segments versus AAC from all slices cranial to the aortoiliac bifurcation. AAC was quantified by modified Agatston score (AS) in 100 Framingham Heart Study participants (60±13years old, 51 men). We compared the AS measured from 5-cm and 8-cm segments with the ASALL (total visualized aorta). Of 100, 73 participants had AAC >0. The total length of aorta imaged was ≥8cm in 84% of participants. Qualitatively, 5-cm and 8-cm segments correctly identified 96% and 99%, respectively, of participants as having or not having AAC. Quantitatively, AS8cm was within 20% of ASALL in four-fifths and within 30% of ASALL in nine-tenths of participants. AS5cm more severely underestimated ASALL. The use of S1 as the caudal imaging landmark in a 15-cm slab yields ≥8cm aortic coverage in most adults. Both 5-cm and 8-cm analysis strategies are comparable to analyzing the total visualized abdominal aorta for prevalent AAC, but only 8-cm segment analysis yields quantitatively similar measures of AAC.

The Relationship between Small Pulmonary Vascular Alteration and Aortic Atherosclerosis in Chronic Obstructive Pulmonary Disease: Quantitative CT Analysis

The relationship between chronic obstructive pulmonary disease (COPD) and atherosclerosis has been suggested; this association may relate to systemic inflammation and endothelial dysfunction, which can lead to alteration of small pulmonary vessels. The relationship between atherosclerosis and small pulmonary vessel alteration, however, has not been assessed in COPD patients. We tested the hypothesis that the severity of thoracic aortic calcification measured by computed tomography (CT) would be associated with the total cross-sectional area of small pulmonary vessels (CSA) on CT images. The study was approved by the institutional review board and was Health Insurance Portability and Accountability Act-compliant. Informed consent was waived. For 51 COPD patients enrolled in the National Heart, Lung, and Blood Institute Lung Tissue Research Consortium, we calculated the percentage of total CSAs of less than 5 mm² for the total lung area (%CSA<5). Thoracic aortic calcification, quantified by modified Agatston score, was measured. The correlations between thoracic aortic calcification score and %CSA<5, pulmonary function, and extent of emphysema were evaluated. Multiple linear regression analysis using aortic calcification score as the dependent outcome was also performed. The %CSA<5 had a significant negative correlation with the thoracic aortic calcification score (r = -0.566, P < .0001). Multiple linear regression analysis showed significant correlation between the aortic calcification score and %CSA<5 (P < .0001) independent of age, pack-years, extent of emphysema, and FEV1%. Atherosclerosis, assessed by aortic calcification, is associated with the small pulmonary vascular alteration in COPD. Systemic inflammation and endothelial dysfunction may cause the close relationship between atherosclerosis and small pulmonary vessel alteration.

Eligibility of Individuals With Subclinical Coronary Artery Calcium and Intermediate Coronary Heart Disease Risk for Reclassification (from the Framingham Heart Study)

Coronary artery calcium (CAC) predicts risk for coronary heart disease (CHD) events and perhaps CAC testing may further stratify risk in individuals at intermediate CHD risk. We sought to determine the percentage of participants at intermediate CHD risk who could potentially be reclassified as having a high CHD risk based on the presence of a high CAC score and the prevalence, treatment, and control of CHD risk factors in this group. Framingham Heart Study Offspring and Third Generation cohort participants underwent multidetector computed tomography (n = 3,529, mean age 51 years, 48% women). High CAC was defined as >or=90th age- and gender-specific percentiles based on a healthy reference group or by an absolute modified Agatston score of 100 HU. Prevalence of CHD risk factors (hypertension, hypercholesterolemia, high low-density lipoprotein cholesterol, low high-density lipoprotein cholesterol, smoking, and obesity), their treatment, and control was compared between nondiabetic participants with and without high CAC. Of the 595 participants at intermediate CHD risk, 22% had CAC >or=90th percentile and 39% had CAC >or=100 and could be eligible for reclassification as having a high CHD risk based on the presence of a high CAC score. There were no statistically significant differences in prevalence, treatment, and control of risk factors between those with and without high CAC. In conclusion, prevalence of CHD risk factors did not differ between intermediate-risk participants with and without high CAC. Approximately 25% of intermediate-risk individuals have high CAC scores and may be eligible for reclassification into a higher-risk category.

Quantification and Characterization of Carotid Calcium with Multi-detector CT-angiography

The aim of this study was to assess the accuracy of CT-angiography for identification and measurement of calcification of carotid atherosclerotic plaques and to characterise the content and distribution pattern of mineral calcium (hydroxyapatite, Ca) in carotid bifurcations and investigate its relationship with neurological symptoms. Twenty-six patients with ICA stenosis > 60% (13 symptomatic, 13 asymptomatic) were selected for study. Ca was estimated from the weight of the ashed remnants of carotid endarterectomy (CEA) specimens in 11 patients. Calcium content (calcification volume (mm3),CV), and average calcium density (Hounsfield units (HU),CD), were determined by CT-angiography. The distribution pattern of calcium within the lesion (base (posterior), shoulder or luminal surface) was assessed in all cases. CT-derived estimation of CV and Ca mass (modified Agatston Score, (mAS) = CV x CD) showed a good correlation with its direct measurement in CEA specimens (r = 0.911 and 0.993 respectively, p < 0,005). Asymptomatic patients with ICA stenosis > 60% showed statistically significant higher content of Ca than those who were symptomatic (mAS: 122.6 +/- 138.0 HU mm3 vs 42.8 +/- 59.1 HU mm3, p = 0.04). Calcification on the surface of the plaque was observed more commonly in asymptomatic patients (9/12 vs 3/15, p = 0.006). Non-calcified or plaques with posterior calcification were 12 times more likely to be symptomatic (OR: 12, 95%CI 1.5-91.1, p = 0.021). CT-angiography permits the reliable quantification of calcification of carotid plaques. A lower content of calcium in carotid plaques, as well as its distribution in the base of the lesion, was associated with a greater prevalence of neurological symptoms. These parameters may be useful to identify those patients at higher risk of stroke.

Evidence for lower variability of coronary artery calcium mineral mass measurements by multi-detector computed tomography in a community-based cohort—Consequences for progression studies

Purpose To compare the measurement variability for coronary artery calcium (CAC) measurements using mineral mass compared with a modified Agatston score (AS) or volume score (VS) with multi-detector CT (MDCT) scanning, and to estimate the potential impact of these methods on the design of CAC progression studies. Materials and methods We studied 162 consecutive subjects (83 women, 79 men, mean age 51 ± 11 years) from a general Caucasian community-based cohort (Framingham Heart Study) with duplicate runs of prospective electrocardiographically-triggered MDCT scanning. Each scan was independently evaluated for the presence of CAC by four experienced observers who determined a “modified” AS, VS and mineral mass. Results Of the 162 subjects, CAC was detected in both scans in 69 (42%) and no CAC was detected in either scan in 72 (45%). Calcium scores were low in the 21/162 subjects (12%) for whom CAC was present in one but not the other scan (modified AS <20 in 20/21 subjects, mean AS 4.6 ± 1.9). For all three quantification algorithms, the inter- and intraobserver correlation were excellent ( r > 0.96). However, the mean interscan variability was significantly different between mineral mass, modified AS, and VS (coefficient of variation 26 ± 19%, 41 ± 28% and 34 ± 25%, respectively; p < 0.04), with significantly smaller mean differences in pair-wise comparisons for mineral mass compared with modified AS ( p < 0.002) or with VS ( p < 0.03). The amount of CAC but not heart rate was an independent predictor of interscan variability ( r = −0.638, −0.614 and −0.577 for AS, VS, and mineral mass, respectively; all p < 0.0001). The decreased interscan variability of mineral mass would allow a sample size reduction of 5.5% compared with modified AS for observational studies of CAC progression and for randomized clinical trials. Conclusion There is significantly reduced interscan variability of CAC measurements with mineral mass compared with the modified AS or VS. However, the measurement variability of all quantification methods is predicted by the amount of CAC and is inversely correlated to the extent of partial volume artifacts. Moreover, the improvement of measurement reproducibility leads to a modest reduction in sample size for observational epidemiological studies or randomized clinical trials to assess the progression of CAC.

Threshold-dependent variability of coronary artery calcification measurements — implications for contrast-enhanced multi-detector row-computed tomography

Introduction The present study investigated the threshold-dependent variability of coronary artery calcification (CAC) measurements and the potential to quantify CAC in contrast-enhanced multi-detector row-computed tomography (MDCT). Methods We compared the mean CT attenuation of CAC to luminal contrast enhancement of the coronary arteries in 30 patients ( n = 30) undergoing standard coronary contrast-enhanced spiral MDCT. The modified Agatston score [AS], calcified plaque volume [CV], and mineral mass [MM]) at four different thresholds (130, 200, 300, and 400 HU) were measured in 50 patients who underwent non-contrast-enhanced MDCT. Results Mean CT attenuation of CAC was similar to the attenuation of the contrast-enhanced coronary lumen (CAC 297.1 ± 68.7 HU versus 295 ± 65 HU ( p < 0.0001), respectively). Above a threshold of 300 HU CAC measurements significantly varied to standard measurements obtained at a threshold of 130 HU ( p < 0.0001). The threshold-dependent variation of MM measurements was significantly smaller than for AS and CV (130 HU versus 400 HU: 63, 75, and 81, respectively; p < 0.001). These differences resulted in a change of age and gender based percentile category for AS in 78% of subjects. Discussion We demonstrated that CAC measurements are threshold dependent with MM measurements having significantly less variation than AS or CV. Due to the similarity of mean CT attenuation of CAC and the contrast-enhanced coronary lumen accurate quantification of CAC may be difficult in standard coronary contrast-enhanced spiral MDCT.

Vascular calcification in ex vivo carotid specimens: precision and accuracy of measurements with multi-detector row CT.

To test the accuracy and precision of multi-detector row computed tomography (CT)-derived measurements of vascular calcification in ex vivo human carotid endarterectomy (CEA) specimens. Sixteen ex vivo CEA specimens were imaged with multi-detector row CT. Multi-detector row CT-derived calcium scoring algorithms (ie, mineral mass and volume score) were compared with the mass and volume of ashed remnants of the CEA specimens. Bland-Altman analysis was performed to assess the mean (ie, bias) and SD (ie, precision) of differences between multi-detector row CT- and ashing-derived measurements. In addition, conventional Agatston score, volume score, mineral mass, and modified Agatston score were calculated for each specimen by using a number of scanning protocols. Images were obtained at a section thickness of 1.25 mm by using different tube energy settings and tube currents. Specimens were also imaged at different section thicknesses with fixed combinations of tube energy and tube current. To compare measurement variability of scoring methods, coefficients of variation for all protocols were calculated. Both mean multi-detector row CT-derived mineral mass and mean ashing-derived mineral mass were 0.129 g +/- 0.173 (r = 0.99, P <.001). Mean multi-detector row CT- and ashing-derived volumes were 339.94 mm3 +/- 395.4 and 39.48 mm3 +/- 55.76, respectively (r = 0.95, P <.001). Measurement bias relative to the reference ashing values was high (2,800.0%) for volume score and low (2.58%) for mineral mass. Measurement precision was 0.6% for volume score and greater than 0.0005% for mineral mass. Mean coefficients of variation for all CT protocols were 5.0% +/- 4.2 and 4.9% +/- 4.2 for mineral mass and modified Agatston score, respectively, and 16.0% +/- 9.2 and 14.5% +/- 3.9 for conventional Agatston and volume scores, respectively (P <.001). Compared with the conventional volume score, multi-detector row CT-derived mineral mass is a less biased and more precise measurement of the mineral content of nonmoving ex vivo CEA specimens. Mineral mass and modified Agatston score are more reproducible than conventional volume and Agatston scores.