Electron Beam Computed Tomography Research Articles

Abstract P330: Cardiovascular Adipose Depots Of The Heart And Aorta Are Associated With CVD Risk Factors And Vascular Calcification In Women With SLE

Introduction: Women with systemic lupus erythematosus (SLE) are at greater risk of developing cardiovascular disease (CVD), which is not explained by traditional CVD and SLE-related risk factors. Mounting evidence implicates small visceral adipose depots surrounding the heart and vasculature in the pathogenesis of CVD. Previously, we found that women with SLE had a greater volume of aortic perivascular adipose tissue (aPVAT) compared to healthy controls (HC). Here we quantify epicardial (EPI), paracardial (PARA), and total heart (TOT = EPI+PARA) adipose and evaluate their associations with aPVAT, CVD risk factors and coronary artery (CAC) and aortic (AC) calcification. Design: Data included clinically CVD-free SLE women never (SLEc-) or ever (SLEc+) on corticosteroids, and healthy controls (HC) (HEARTS cohort). Electron beam CT scans were used to quantify adipose depots and AC/CAC. Logistic and linear regressions were used and final models were adjusted for waist-to-hip ratio. Results: In this study, age- and race-matched women participated: 15 SLEc-, 15 SLEc+, and 15 HC. More SLE women had hypertension (p=0.04), elevated circulating eSelectin (p=0.04), albumin (p=0.01), and homocysteine (p=0.02) compared to HC. SLEc+ women had decreased circulating C3 (p=0.04) and C4 (p<0.01) compared to SLEc- women. TOT tended to be greater in SLE (mean(std): 108(92)cm3, p=0.07) vs. HC (85.2(30) cm3) and in SLEc+ (122(45) cm3,p=0.06) vs. vs SLEc- (93.5(32) cm3). There were no differences in EPI (p=0.2) or aPVAT (p=0.3), but PARA was greater in SLEc+ (54.2(27) cm3) vs. SLEc-(36.9(19) cm3) (p=0.05). TOT was correlated with aPVAT in SLE (rho,p: 0.47, 0.01) and HC (0.69, <0.01) with PARA volume (SLE(0.43, 0.02) and HC (0.57, 0.03)) driving this association. In HC, EPI and PARA were correlated with insulin (p<0.03) and HOMA-IR (p<0.04) while PARA was correlated with CRP (p=0.04). Glucose levels were correlated with EPI in SLEc+ (0.53, 0.04) and with PARA in SLEc- (-0.55, 0.03). AC was detected in 21/28 SLE women and 11/15 HC while CAC was detected in 13/28 SLE and 4/15 HC. Only aPVAT was associated with increasing AC (OR(95%CI),p): 1.09 (1.0-1.2), 0.04) and CAC (1.11 (1.0-1.2), 0.03) in SLEc+. In adjusted models, only aPVAT(log) remained associated with greater extent of AC in SLE(β(SE),p: 2.90(1.3), 0.04), which was driven by SLEc+ (5.13(1.8), 0.02) women. Conclusion: Adipose depots surrounding the heart and vasculature are greater in clinically CVD-free women with SLE and specifically SLEc+, with significant associations among CVD risk factors and calcification dependent on their location. Corticosteroid treatment may suppress circulating inflammatory markers, but is associated with greater adipose volumes surrounding the heart and increased calcification. Just as AC generally precedes CAC development, aPVAT may be a precursor to extensive PARA and EPI development, with PARA more strongly associated.

Cardiorespiratory fitness and coronary artery calcification in women

IntroductionCardiorespiratory fitness (fitness) has been shown to be inversely associated with coronary heart disease morbidity and mortality. The cardioprotective mechanisms of fitness are not well defined. The goal of this study was to assess the relationship between coronary artery calcification as a measure of atherosclerotic burden and fitness in a large population of generally healthy women. Methods5341 women ages 40–90 years seen between 1997 and 2007 underwent maximal treadmill exercise testing and coronary artery calcium (CAC) scanning. Fitness was reported in METs estimated from maximal treadmill time, grade, and speed. CAC was characterized dichotomously as CAC = 0 versus CAC > 0, and CAC < 100 versus CAC ≥ 100. Multiple logistic regression models were used to calculate the adjusted odds ratio of any CAC (CAC > 0) and CAC ≥ 100. Fitness was added to these models continuously and categorically based on standard and sample-specific cut-points. ResultsWith a mean age of 52.0 years, the overall prevalence of detectable CAC was 19.9% and CAC ≥ 100 was 6.8%. Univariable analysis showed a modest inverse relationship between fitness and CAC > 0 (24% in low fit versus 19% in high fit, p-trend = 0.006), with a similar trend observed for CAC ≥ 100. In multivariable models, age adjustment diminished this association and the relationship was no longer statistically significant after adjustment for traditional risk factors. ConclusionsThe cardioprotective benefit of fitness does not appear to be mediated by an effect independent of traditional risk factors on the development of calcified coronary atherosclerosis as measured by electron beam tomography.

Relation of Serum Uric Acid to Severity and Progression of Coronary Artery Calcium in Postmenopausal White and Filipino Women (from the Rancho Bernardo Study)

Elevated serum uric acid (UA) is associated with cardiovascular disease (CVD) but its association with coronary artery calcium (CAC) is inconsistent. This study examined ethnic differences in the association of UA levels with CAC severity and progression. Participants included 202 white and 166 Filipino postmenopausal women without known CVD. White women originated from the Rancho Bernardo cohort study, whereas Filipino women were convenience sampled from comparable localities. Baseline UA levels and CVD risk factors were measured in 1995 to 1999. CAC was assessed by electron beam computed tomography (EBCT) in 2000 to 2002 (EBCT1) and repeated in 2005 to 2007 (EBCT2). EBCT1 CAC density scores were categorized by severity: minimal 0 to 10, mild 11 to 100, moderate 101 to 399, and severe ≥400. Progression was defined as CAC volume score increases of ≥2.5 mm3 between scans. White women were older at baseline than Filipinas (64.6 vs 59.3 years, p<0.001). Filipinas had increased UA levels (235.8 vs 294.2 μmol/L, p<0.001), diabetes (35.5% vs 5.2%, p<0.001), hypertension (69.6% vs 45.2%, p<0.001), and statin use (32.8% vs 18.7%, p=0.002). CAC severity did not vary by ethnicity (p=0.502), but Filipinas experienced more CAC progression than whites (53.0% vs 39.1%, p=0.016). Adjustment for CVD risk factors identified a positive association between UA levels and increasing CAC severity at EBCT1 in Filipinas (odds ratio [OR] 1.34, 95% confidence interval [CI] 1.05 to 1.71) but not whites (OR 0.94, 95% CI 0.71 to 1.25). Higher UA levels predicted CAC progression in both cohorts (OR 1.26, 95% CI 1.02 to 1.56). In conclusion, these results support use of UA as an ethnicity-specific marker of CAC severity and as a marker of CAC progression among postmenopausal women.

It’s time for a practical method quantifying vascular calcification

It’s time for a practical method quantifying vascular calcification

Adverse pregnancy outcomes and subsequent risk of cardiovascular disease in women with systemic lupus erythematosus

Background/objective Patients with systemic lupus erythematosus (SLE) are at increased risk for adverse pregnancy outcomes and cardiovascular disease (CVD). The objective of this exploratory study was to investigate the association between a history of adverse pregnancy outcomes and subsequent risk of subclinical CVD assessed by imaging studies and verified clinical CVD events in 129 women with SLE. Methods The occurrence of adverse pregnancy outcomes, specifically pre-eclampsia, preterm birth and low birth weight was ascertained by questionnaire. Subclinical CVD was assessed by coronary artery calcium (CAC) as measured by electron beam CT and carotid plaque measured by B mode ultrasound. Clinical CVD events were verified by medical record review. Logistic regression was used to estimate the association of pregnancy complications with occurrence of subclinical CVD and clinical CVD with a priori adjustment for age, which is associated with CVD and SLE disease duration as a measure of SLE disease burden. Results Fifty-six women reported at least one pregnancy complication while 73 had none. Twenty-six women had at least one pregnancy complicated by pre-eclampsia and were more likely to have a CAC score greater than or equal to 10 (adjusted OR=3.7; 95% CI 1.2 to 11.9), but the presence of plaque was not associated with this pregnancy complication, OR=1.1, (95% CI 0.4 to 2.8). Low birth weight and preterm birth were not associated with CAC or plaque. Conclusions Patients with SLE with a history of pre-eclampsia had a higher rate of subclinical CVD as measured by CAC score. Future studies are needed to confirm the relationship between adverse pregnancy outcomes and subsequent subclinical CVD and clinical CVD events.

Determinants of intrathoracic adipose tissue volume and associations with cardiovascular disease risk factors in Amish

Background and aimHypothesizing that intrathoracic fat might exert local effects on the coronary vasculature, we assessed the association of intrathoracic fat volume and its two subcomponents with coronary artery calcification (CAC) in 909 relatively healthy Amish adults. Methods and resultsIntrathoracic fat, which is comprised of fat between the surface of the heart and the visceral epicardium (epicardial fat) and fat around the heart but outside of the fibrous pericardium (pericardial fat), was measured from electron beam CT scans. We examined the association between intrathoracic fat volume and cardiovascular disease risk factors in multivariate regression model. Fat volume in the epicardial and pericardial compartments were highly correlated with each other and with body mass index. Neither CAC extent nor CAC presence (Agatston score > 0) was associated with increased intrathoracic fat volume in sex-stratified models adjusting for age (p > 0.10). Intrathoracic fat volume was significantly correlated with higher systolic/diastolic blood pressure, pulse pressure, fasting glucose, insulin, triglyceride and lower high-density lipoprotein cholesterol in sex-stratified models adjusting for age (p < 0.05). However, associations were attenuated after further adjustment for body mass index. ConclusionsThese data do not provide support for a significant role for intrathoracic fat in the development of CAC.

Enhanced [18F]fluorodeoxyglucose accumulation in the right ventricular free wall predicts long-term prognosis of patients with pulmonary hypertension

Background: We have previously demonstrated that [18F]fluorodeoxyglucose (FDG) accumulation evaluated by ECG gated positron emission tomography (PET) is increased in the right ventricular (RV) free wall of patients with pulmonary hypertension (PH) and that this accumulation is ameliorated after medical therapy associated with hemodynamic improvement. However, it remains to be examined whether RV FDG accumulation has a prognostic significance in patients with PH. Methods and results: From March 2001 to June 2004, we performed gated FDG-PET in 27 patients with PH, including 18 with pulmonary arterial hypertension and 9 with chronic thromboembolic pulmonary hypertension. We examined baseline clinical parameters, invasive hemodynamic data, imaging data with cardiac MR, electron beam CT and FDG-PET quantified by calculating standardized uptake value (SUV) and corrected for partial volume effect based on the RV free wall thickness, the composite primary endpoint defined as all-cause mortality, lung transplantation, hospitalization for progression of PH and deterioration of NYHA functional class and/or >15% reduction in 6-min walk distance (6MWD) from baseline, and all-cause mortality as the second endpoint. During the mean follow-up period of 66 months, 15 patients reached the composite primary endpoint, including all-cause mortality in 4, lung transplantation in 1, hospitalization for PH progression in 9, deterioration of NYHA functional class and/or >15% reduction in 6MWD from baseline in 1 and death in 11 (41%). In FDG-PET measurements, corrected RV free wall SUV was significantly increased in the endpoint group compared with the no endpoint group (10.1±2.7 vs. 7.6±2.2, P=0.02). Univariate COX hazard analysis showed that the corrected RV SUV of FDG was significantly correlated with the composite endpoint (hazard ratio 1.25, 95% confidence interval 1.04-1.51, P=0.04). This relationship remained significant even after adjustment for NYHA functional class or 6MWD. In Kaplan-Meier analysis for the composite primary endpoint, patients with a corrected RV SUV of FDGSUV ≥8.5 had a significantly poor prognosis compared with those with <8.5 (log-rank P=0.005 for the composite endpoint, P=0.07 for all-cause mortality). Furthermore, the corrected RV SUV of FDG at 3months after epoprostenol treatment could predict survival in patients with PAH better than the reduction in pulmonary vascular resistance by ≥30% (log-rank P=0.02, P=0.34, respectively). Conclusions: These results indicate that enhanced FDG accumulation in the RV is a useful prognostic factor in patients with PH.

Incidence of subclinical atherosclerosis as assessed with electron beam CT in adults ≤45 years old

Coronary atherosclerosis is a continuous process beginning early in life, with a long and clinically asymptomatic phase, before manifestations appear in middle and/or late adulthood. Coronary artery calcification (CAC) is a well-established marker of atherosclerosis; nonetheless, the clinical validity of CAC in young adults – traditionally considered as a population group of low cardiovascular risk – remains unclear. We aimed to assess the prevalence of CAC in a population of young individuals without previous history of coronary artery disease (CAD) in the UK and its association with conventional cardiovascular risk factors. This analysis includes 4186 asymptomatic young individuals who underwent electron beam computed tomography (EBCT) at European Scanning Centre (London, UK) between January 2002 and December 2009 as part of a preventive healthcare examination. Demographic information and the presence of cardiovascular risk factors were abstracted from referral letters and/or questionnaires completed by the patients prior to their tests. Individuals with previously documented CAD or chronic kidney disease were excluded. All EBCT CAC studies were performed using the same scanner (Imatron C300 Ultrafast computed tomography scanner, GE Healthcare, London, UK) and the same scanning protocol. The age (mean SD) of the study cohort was 40.5 3.6 years (range 26–45 years, 83.8% males). The majority (81.6%) of this cohort was Caucasians, followed by South Asians (8%). Hypertension, dyslipidaemia, and diabetes mellitus (DM) were present in 15.5, 7.9, and 2.8% of individuals, respectively. Family history of premature CAD was present in 17%, while 17.4% were smokers. The proportion of individuals with hypertension and dyslipidaemia increased with increasing age, while the prevalence of smoking and that of a positive family history for CAD decreased (Table 1). Overall, CAC was present in 21.8% of the cohort, while individuals with CAC comparing with those with CAC score 0 were males (95.2 vs. 80%, p 1000 were 78.2, 19, 2.1, 0.5, and 0.2%, respectively. The prevalence and distribution of CAC among various age groups are shown in Table 1. CACwas found in 24.8%ofmales (CAC score 1–100, 101–400, 400–1000, >1000 in 21.6, 2.5, 0.5, and 0.1%, respectively) and 6.6% of females (CAC score 1–100, 101–400, 400–1000, >1000 in 5.4, 0.6, 0.15 and 0.4%, respectively) (p 0) was identified in 20%. There was a male preponderance. Assessment of CAC score is a useful clinical tool in young individuals, as it can confirm the presence of subclinical atherosclerosis. In this way, the abnormal levels of calcium may place individuals into a higher risk group in terms of future events and lead to more aggressive treatment with preventative therapies.

Gender-specific association of coronary artery calcium and lipoprotein parameters: The Heinz Nixdorf Recall Study

BackgroundCoronary atherosclerosis can be detected by computed tomography. The amount of coronary artery calcification (CAC) is related to cardiovascular risk factors, the strength of the gender specific relation between lipoprotein parameters and CAC has not extensively been studied. Especially, the role of routinely determined lipoproteins in contrast to less common and computed lipid parameters (e.g. ratios) remains to be clarified. Methods and resultsThe study cohort (n = 3956, 52% women, age 45–75 years) was randomly selected from three cities of a German metropolitan area. Lipoproteins–low-and high density lipoprotein (LDL-C/HDL-C), total cholesterol, apolipoprotein A-1 and B (apoA-1/apoB) as well as lipoprotein (a) (Lp(a)) were measured, while non-HDL-C was calculated. All participants received an electron-beam computed tomography (EBCT) for quantification of CAC. Adjusted for age and cardiovascular risk factors, CAC increased by a factor of 1.97 (1.51–2.57, 95% CI) and 1.94 (1.53–2.45, 95% CI) comparing the fourth to the first quartile of LDL-C for men and women, respectively. This association with LDL-C was also found after dichotomization of CAC at thresholds >0, ≥100 and ≥400. The best association of CAC was, however, found to be apoB and the second best was non HDL-C, in both men and women. For apoB, the model including all risk factors reached an explained variance for CAC of 20.2% in men and of 21.6% in women. When using LDL-C as a given parameter according to the current practice and advice, HDL-C in men and apoB in women provided an additional but small benefit. ConclusionApoB showed the best association with CAC compared to all other tested lipoproteins. Neither the ratio LDL-C/HDL-C nor apoB/apoA-1, or Lp(a) revealed a closer association with CAC. While lipoproteins are related to CAC more closely in women than in men, their association with CAC is, however, not particularly strong. Our results may influence primary and secondary prevention advices in order to improve detection of subclinical atherosclerosis, for which lipoprotein parameters can only play a minor role.

Abstract 84: Serum Amyloid A Does Not Modulate the Inverse Association of HDL with Coronary Artery Calcification in Type 2 Diabetes

Introduction Although high-density lipoprotein (HDL) is inversely correlated with cardiovascular risk, HDL loses its protective role in pathologic inflammatory states like type 2 diabetes (T2DM). HDL dysfunction contributes to accelerated atherosclerosis in T2DM, but the mechanism is incompletely defined. The acute phase reactant serum amyloid A (SAA) displaces apolipoprotein A-I and may impair HDL-mediated reverse cholesterol efflux. We hypothesized that SAA alters the inverse association between HDL and coronary artery calcium (CAC) in the Penn Diabetes Heart Study, a cross-sectional study of T2DM patients free of overt cardiovascular or renal disease. Methods We measured SAA in serum samples by immunonephelometry (N=975; mean age 58 ± 9 years; 63% male, 57% Caucasian; mean BMI 33 ± 6 kg/m 2 ). HDL was measured enzymatically in lipoprotein fractions after ultracentrifugation. Agatston CAC scores were quantified from electron beam tomography at the same visit. Spearman correlation and logistic regression were used to test associations of SAA with clinical factors and metabolic syndrome. We used Tobit regression to analyze associations between CAC and HDL, both overall and stratified by 3 categories of SAA: undetectable, lower half detectable, and upper half detectable. Results Spearman correlations revealed moderate association of SAA with C-reactive protein (r=0.52) and weak associations of SAA with BMI (r=0.25) and HDL (r=0.17; all p&lt;0.001). In logistic regression, the group with highest SAA levels had increased odds of metabolic syndrome compared to those with undetectable levels (OR 1.56, 95% CI 1.03 to 2.38, p=0.036). In adjusted Tobit regression, HDL was inversely associated with CAC (Tobit coefficient for 1-SD increase in HDL: -0.30; 95% CI -0.54 to -0.06; p=0.013). Across the categories of SAA, however, there was no difference in the association of HDL with CAC (Tobit coefficient for 1-SD increase in HDL: -0.17 [95% CI -0.49 to 0.16] for undetectable vs. -0.31 [95% CI -0.79 to 0.17] for lower half detectable vs. -0.49 [95% CI -1.01 to 0.03] for upper half detectable). Conclusions Despite the association of SAA with metabolic syndrome, these data suggest that elevated SAA may not change the inverse relationship of HDL with CAC in T2DM.

Vascular Calcification in Diabetes: Mechanisms and Implications

Cardiovascular disease (CVD) remains the leading cause of death among adults with diabetes, and CVD prevention remains a major challenge. Coronary artery calcium (CAC) score measured by electron beam tomography (EBT) or multi-slice detector computed tomography correlates closely with plaque burden and coronary angiography, and predicts coronary events independently of other risk factors. Further, progression of CAC over several years has been shown to predict increased mortality. Coronary calcification is an active process strongly associated with atherosclerotic plaque evolution and is an accepted surrogate endpoint in studies of patients with diabetes older than 30. In this review, recent findings regarding the mechanisms and implications of vascular calcification in diabetes will be discussed.

Comparison of coronary calcification among South Asians and Caucasians in the UK

Most of the published studies have shown racial differences in the prevalence and severity of coronary artery calcification (CAC) [1–3]. Although individuals of South Asian origin (India, Pakistan, Sri Lanka, Nepal & Bangladesh) represent 20% of the world population and considered as one of the largest ethnic groups at risk of coronary heart disease (CHD), they are under-represented in studies investigating the presence of CAC [4,5]. Therefore, we compared the prevalence of CAC in Caucasians and South Asians who underwent electron beam computed tomography (EBCT) at the European Scanning Centre, London, UK. CAC score (CACS) was performed on an Imatron C300 Ultrafast EBCT scanner (GE Healthcare), using a standard method with calcium deposition scored according to Agatston method [6]. Demographic information and the presence of risk factors were abstracted from referral letters and questionnaires completed by the patients prior to their test. Individuals with previously documented CHD or chronic kidney disease were not included in the study. CACSwas assessed in 935 South Asians (739males and 196 females) and 13,501 Caucasians (10,232 males and 3269 females). Gender distribution between Caucasians and South Asians was similar (p= 0.1); conversely, the Caucasians group was older to its South Asians counterpart (52.8 ± 9.6 vs. 50.6 ± 10.3, respectively; p b 0.001); while on the other hand, South Asians appeared to have a higher prevalence of diabetes mellitus (17.5% vs. 4.3%; p b 0.0001). Interestingly, therewas no difference in the prevalence of smoking between the 2 groups (15% vs. 12.1%; p = 0.06), of hypertension (31.3% vs. 25.3%; p b 0.4), family history of CHD (22.8% vs. 16.1%; p = 0.3), and hyperlipidemia (24.5% vs. 17.3%; p = 0.3). The prevalence of CAC (CACS N 0) was similar between Caucasians and South Asians (50.9% vs. 50.8%; p= 0.9), although a statistically significant difference in the prevalence of CAC in South Asians N50 years should be noted (p= 0.01). South Asian males showed a higher mean CACS as compared to Caucasians (179.6 ± 545.1 vs. 144.1 ± 420.1; p= 0.03). Although, in malesb50 years, therewasno statistically significantlydifference inmean CACS between South Asians and Caucasians (36.1 ± 277.8 vs. 23.8 ± 104.2; p= 0.06), inmales N50 years old thedifference inmeanCACSwas significant (South Asians, 339.1 ± 702.9 vs. Caucasians 232.3 ± 528.7; p b 0.0001). On the other hand, no difference was observed in the mean CACS between South Asian and Caucasian females (South Asians 59.2 ± 224.9 vs. Caucasians 56.6 ± 219.2; p = 0.86). South Asian females b50 years and South Asian females N50 years had similar mean CACS compared to Caucasians. CACS subgroups for age, gender and racial subgroups are tabulated in Table 1. We observe that in South Asian males N50 years old, the mean CACS was significantly higher than the Caucasians (p b 0.0003) and there was significant difference in the proportion of the population in any CACS range (p= 0.01). South Asians seem more prone to extensive calcification, as South Asians had higher mean CACS than Caucasians in both sex and all age groups (Fig. 1). Furthermore, age seems to play an important

A cardiac phantom study on quantitative correction of coronary calcium scores on multi-detector, dual source and electron beam tomography for velocity, calcification density and acquisition time

A cardiac phantom study on quantitative correction of coronary calcium scores on multi-detector, dual source and electron beam tomography for velocity, calcification density and acquisition time

Self-reported and accelerometer-derived physical activity levels and coronary artery calcification progression in older women

Despite the well-supported biological link between physical activity (PA) and atherosclerosis, most previous studies have reported a null association between PA and coronary artery calcification (CAC). The aim of this study was to examine the relationship between PA and CAC progression in 148 Healthy Women Study (HWS) participants over 28 years of observation. The HWS was designed to examine cardiovascular risk factor changes from premenopause to postmenopause. Based on CAC scores collected on two follow-up visits (electron beam tomography [EBT] 1 and EBT4) scheduled 12 years apart, participants were classified into one of three groups: (1) no-detectable CAC group (n = 37; 0 CAC on both visits); (2) incident CAC group (n = 46; 0 CAC on the first visit and >0 CAC on the last visit); or (3) prevalent CAC group (n = 65; >0 CAC on both visits). PA data were collected regularly throughout the study using self-report questionnaires and accelerometers on EBT4. The percentage of HWS participants with no detectable CAC decreased from 56.1% on EBT1 to 25.0% on EBT4. Times spent per day in accumulated moderate- to vigorous-intensity PA (MVPA) and bouts of MVPA were each significantly higher in the no-detectable CAC group when compared with the prevalent CAC group (both P ≤ 0.01). After covariate adjustment, these differences remained statistically significant (both P < 0.05). Although self-reported summary estimates collected throughout the study were significantly associated with accelerometer data on EBT4, there were no significant differences in self-reported PA levels by CAC group after covariate adjustment. Study findings suggest that low levels of accelerometer-derived MVPA may be indicative of subclinical disease in older women.

CT Systems

Computed tomography (CT) was introduced in the early 1970s, and has since then revolutionized diagnostic imaging. Today, CT is the backbone of radiology. In this article we review different CT system design concepts. We start with an overview of the “classic” four generations of CT systems: the first generation head scanners relying on the “translate–rotate” principle, second generation scanners with a small detector array instead of a single detector, modern third generation “rotate–rotate” CT scanners with a detector fan wide enough to cover a whole-body scan field of view, and finally the currently abandoned fourth generation CT systems with a rotating X-ray tube and stationary detector. We present basic concepts and a short history of multidetector row CT (MDCT), illustrating its potential and limitations. Then, we introduce novel system concepts, such as CT systems with area detectors and dual source CT, that aim at solving remaining limitations of MDCT. We explain the basic system options to acquire dual energy CT data or spectrally resolved CT data. Finally, we briefly touch alternative system designs, such as electron beam CT, CT systems with inverse geometry, interior tomography CT, and phase contrast CT.

Incidental findings on electron beam tomography renal angiography in hypertensive patients

To evaluate the prevalence, spectrum, and significance of incidental lesions identified on electron beam tomography (EBT) renal angiography performed to investigate renovascular hypertension. Materials and methods: EBT renal angiography images of 148 cases were evaluated in terms of renal artery variations and renal artery stenosis. Extravascular renal findings, abdominal aorta, iliac artery, liver and gallbladder findings, vertebral lesions, and other intraabdominal organ findings were assessed during the examination. Results: No incidental finding was found in 30 cases (20.2%) in total. The most frequent incidental findings were benign ones without any clinical significance. A total of 13 (8.7%) clinically significant findings were identified. Conclusion: When evaluating renal EBT angiography, a detailed review of other systems as well as target organ assessment is of crucial importance as it may affect patient prognosis.

Correlation of a self-report and direct measure of physical activity level in the electron-beam tomography and risk assessment among Japanese and US Men in the post World War II birth cohort (ERA JUMP) study.

BackgroundPhysical activity (PA) is complex and a difficult behavior to assess as there is no ideal assessment tool(s) that can capture all contexts of PA. Therefore, it is important to understand how different assessment tools rank individuals. We examined the extent to which self-report and direct assessment PA tools yielded the same ranking of PA levels.MethodsPA levels were measured by the Modifiable Activity Questionnaire (MAQ) and pedometer at baseline among 855 white (W), African-American (AA), Japanese-American (JA), and Korean (K) men (mean age 45.3 years) in 3 geographic locations in the ERA JUMP study.ResultsKorean men were more active than W, AA, and JA men, according to both the MAQ and pedometer (MAQ total PA [mean ± SD]: 41.6 ± 17.8, 20.9 ± 9.9, 20.0 ± 9.1, and 29.4 ± 10.3 metabolic equivalent [MET] hours/week, respectively; pedometer: 9584.4 ± 449.4, 8363.8 ± 368.6, 8930.3 ± 285.6, 8335.7 ± 368.6 steps/day, respectively). Higher levels of total PA in Korean men, as shown by MAQ, were due to higher occupational PA. Spearman correlations between PA levels reported on the MAQ and pedometer indicated positive associations ranging from rho = 0.29 to 0.42 for total activity, rho = 0.13 to 0.35 for leisure activity, and rho = 0.10 to 0.26 for occupational activity.ConclusionsThe 2 assessment methods correlated and were complementary rather than interchangeable. The MAQ revealed why Korean men were more active. In some subpopulations it may be necessary to assess PA domains other than leisure and to use more than 1 assessment tool to obtain a more representative picture of PA levels.

Coronary calcium scanning independently detects coronary artery disease in asymptomatic firefighters: A prospective study

BackgroundSudden cardiac death is the leading cause of death among firefighters in the United States. Fire departments commonly maintain physical examination protocols, often with exercise stress testing, to detect risk of coronary heart disease. ObjectiveWe sought to determine whether coronary calcium detected by electron beam computed tomography (EBCT) adds incremental risk stratification beyond the traditional risk factors in asymptomatic community-based firefighters. MethodsThree hundred ninety nine asymptomatic firefighters underwent a coronary calcium scan on a GE/Imatron C-150 Ultrafast EBCT scanner, using standardized imaging protocols. Framingham risk factor data were obtained on each patient by using a questionnaire. Agatston scores were derived and compared with national database of Agatston scores for asymptomatic populations on the basis of age and sex, allowing determination of a calcium percentile for each score. ResultsCoronary calcium was found only in men >34 years of age. Of the 53% who had positive scans (Agatston score > 0), 87% had higher than average Agatston scores compared with a national database (P < 0.01). Agatston score above the 75th percentile was found in 57% of firefighters. No correlation was observed between traditional risk factors and those with and without coronary calcium. ConclusionsFirefighters have a high burden of calcified coronary atherosclerosis, greater than anticipated on the basis of age and coronary risk factors.

Calcium score of small coronary calcifications on multidetector computed tomography: Results from a static phantom study

IntroductionMulti detector computed tomography (MDCT) underestimates the coronary calcium score as compared to electron beam tomography (EBT). Therefore clinical risk stratification based on MDCT calcium scoring may be inaccurate. The aim of this study was to assess the feasibility of a new phantom which enables establishment of a calcium scoring protocol for MDCT that yields a calcium score comparable to the EBT values and to the physical mass. Materials and methodsA phantom containing 100 small calcifications ranging from 0.5 to 2.0mm was scanned on EBT using a standard coronary calcium protocol. In addition, the phantom was scanned on a 320-row MDCT scanner using different scanning, reconstruction and scoring parameters (tube voltage 80–135kV, slice thickness 0.5–3.0mm, reconstruction kernel FC11–FC15 and threshold 110–150HU). The Agatston and mass score of both modalities was compared and the influence of the parameters was assessed. ResultsOn EBT the Agatston and mass scores were between 0 and 20, and 0 and 3mg, respectively. On MDCT the Agatston and mass scores were between 0 and 20, and 0 and 4mg, respectively. All parameters showed an influence on the calcium score. The Agatston score on MDCT differed 52% between the 80 and 135kV, 65% between 0.5 and 3.0mm and 48% between FC11 and FC15. More calcifications were detected with a lower tube voltage, a smaller slice thickness, a sharper kernel and a lower threshold. Based on these observations an acquisition protocol with a tube voltage of 100kV and two reconstructions protocols were defined with a FC12 reconstruction kernel; one with a slice thickness of 3.0mm and a one with a slice thickness of 0.5mm. This protocol yielded an Agatston score as close to the EBT as possible, but also a mass score as close to the physical phantom value as possible, respectively. ConclusionWith the new phantom one acquisition protocol and two reconstruction protocols can be defined which produces Agatston scores comparable to EBT values and to the physical mass.

Serial block-face scanning electron microscopy combined with double-axis electron beam tomography provides new insight into cellular relationships

To evaluate the advantages of combination of two advanced electron microscopic technologies such as serial block-face scanning electron microscopy and double-axis electron beam tomography, we analyzed the three-dimensional morphology of cellular relationships between dendritic and plasma cells in the synovial membrane from patients with rheumatoid arthritis, using the combined approach.