Calcium Mass Research Articles

A prospective study of the influence of the skeleton on calcium mass transfer during hemodialysis.

BackgroundCalcium gradient, the difference between serum calcium and dialysate calcium d[Ca], is the main contributor factor influencing calcium transfer during hemodialysis. The impact, however, of bone turnover, on calcium mass transfer during hemodialysis is still uncertain.MethodsThis prospective cross-sectional study included 10 patients on hemodialysis for a 57.6±16.8 months, with severe hyperparathyroidism. Patients were submitted to 3 hemodialysis sessions using d[Ca] of 1.25, 1.5 and 1.75 mmol/l in three situations: pre-parathyroidectomy (pre-PTX), during hungry bone (early post-PTX), and after stabilization of clinical status (late post-PTX). Biochemical analysis and calcium mass transfer were evaluated and serum bone-related proteins were quantified.ResultsCalcium mass transfer varied widely among patients in each study phase with a median of -89.5, -76.8 and -3 mmol using d[Ca] 1.25 mmol/L, -106, -26.8 and 29.7 mmol using d[Ca] 1.50 mmol/L, and 12.8, -14.5 and 38 mmol using d[Ca] 1.75 mmol/L during pre-PTX, early post-PTX and late post-PTX, respectively, which was significantly different among d[Ca] (p = 0.0001) and among phases (p = 0.040). Ca gradient and delta of Ca also differed among d[Ca] and phases (p<0.05 for all comparisons), whether ultrafiltration was similar. Serum Osteocalcin decreased significantly in late post-PTX, whereas Sclerostin increased earlier, in early post-PTX.ConclusionsThe skeleton plays a key role in Ca mass transfer during dialysis, either by determining pre-dialysis serum Ca or by controlling the exchangeable Ca pool. Knowing that could help us to decide which d[Ca] should be chosen in a given patient.

Intradialytic alkalinization is a neglected factor affecting calcium mass balance and parathyroid hormone level during haemodiafiltration.

BackgroundThe diffusion gradient between ionized calcium (iCa) in the inlet dialysate and blood is considered to be the main driving force of calcium mass balance (CMB). The intradialytic change of parathyroid hormone (PTH) level corresponds to the change in plasma iCa. In contrast to the widely discussed calcium concentration of dialysis solution, the dialysate pH and bicarbonate concentration (DHCO3), important factors affecting the level of iCa, have not been studied with respect to the intradialytic change of plasma PTH level (ΔPTH) and CMB.MethodsWe measured ΔPTH and CMB (calcium flux from the dialysate to the patient) in 10 stable patients on haemodiafiltration. All patients underwent two treatments differing in DHCO3 (26 versus 32 mmol/L). The dialysate calcium concentration was 1.25 mmol/L for all treatments.ResultsWe found significant difference in ΔPTH, which decreased with 26_DHCO3 and slightly increased with 32_DHCO3 (−110.5 versus +19.7 pg/mL, P < 0.01). CMB was negative for both DHCO3, but with higher DHCO3 there was a trend to minor intradialytic loss of calcium (−108 versus −309 mg).ConclusionsDHCO3 increase at first glance leads to contrasting phenomena: the intradialytic rise of PTH and calcium gain. Both processes are caused by a pH-dependent decrease of plasma iCa, resulting in parathyroid stimulation and intradialytic increase of iCa diffusion gradient. We found no significant correlation between CMB and intradialytic change of plasma total Ca. With respect to plasma PTH level and CMB, the bicarbonate concentration should always be taken into account when selecting the optimal dialysis solution.

The effect of adding glucomannan derived from porang tuber extract (Amorphopallus onchophyllus) on dietary protein utilization in broiler chicken

&lt;p&gt;The aims of this study was to evaluate the affect of dietary addition of glucomannan derived from porang (&lt;em&gt;Amorphophallus oncophyllus&lt;/em&gt;) tuber extract (GEUP) in broiler ration on performance of broiler chicken. There were 160 birds of day old broiler chicks of New Lohmann strain with average initial body weight of 42.08±0.86 g. The study was arranged in a completely randomized design with 5 treatments and 4 replications. Each replication consisted of 8 birds. The treatments applied were T0 = basal ration, T1 = T0 + 0.05% GEUP, T2 = T0 + 0.10% GEUP, T3 = T0 + 0.15% GEUP and T4 = T0 + 0.20% GEUP. The parameters observed were protein digestibility, nitrogen retention, meat calcium and protein mass. The results showed that dietary addition of GUEP significantly (P &amp;lt;0.05) increased coefficient of protein digestibility, meat calcium and protein mass, but had no affect on nitrogen retention. The highest protein digestibility and meat calcium mass were shown at T4, but it was not significantly different from T3, and T2 for protein digestibility. While the highest meat protein mass was at T2 but it was not different with T3 and T4. The conclusion of the study was that dietary supplementation of glucomannan derived from porang tuber extract in broiler up to 0.15% (T3) increased protein digestibility, meat calcium and protein mass with similar nitrogen retention.&lt;/p&gt;

Challenges in the quantification of nutrients in soils using laser-induced breakdown spectroscopy – A case study with calcium

The quantification of the elemental content in soils with laser-induced breakdown spectroscopy (LIBS) is challenging because of matrix effects strongly influencing the plasma formation and LIBS signal. Furthermore, soil heterogeneity at the micrometre scale can affect the accuracy of analytical results. In this paper, the impact of univariate and multivariate data evaluation approaches on the quantification of nutrients in soil is discussed. Exemplarily, results for calcium are shown, which reflect trends also observed for other elements like magnesium, silicon and iron. For the calibration models, 16 certified reference soils were used. With univariate and multivariate approaches, the calcium mass fractions in 60 soils from different testing grounds in Germany were calculated. The latter approach consisted of a principal component analysis (PCA) of adequately pre-treated data for classification and identification of outliers, followed by partial least squares regression (PLSR) for quantification. For validation, the soils were also characterised with inductively coupled plasma optical emission spectroscopy (ICP OES) and X-ray fluorescence (XRF) analysis. Deviations between the LIBS quantification results and the reference analytical results are discussed.

Abstract P369: Relation of Breast Arterial Calcification With Ankle Brachial Index

Presence of breast arterial calcification (BAC) has been shown to be independently associated with increased risk of subclinical cardiovascular disease (CVD), angiographically-defined coronary disease and with incident coronary heart disease, stroke and heart failure. However, a relationship between BAC and peripheral vascular disease has not been established. The ankle brachial index (ABI) is an indicator of the severity of peripheral arterial disease (PAD) that predicts future CVD risk. We utilized cross-sectional data collected at the baseline examination (2012-15) of the MultIethNic Study of BrEast ARterial Calcium Gradation and CardioVAscular Disease (MINERVA Study), a cohort study of 5,145 post-menopausal women who were members of the Kaiser Permanente Medical Care Program of Northern California (KPNC) who were free of clinical CVD at baseline. Presence and gradation (in mg of calcium mass) of BAC in digital mammograms was ascertained with a validated densitometry method. ABI, the average of two ankle systolic pressure readings divided by the average of two brachial systolic pressure readings, was measured by trained and certified personnel after a ten-minute rest. A total of 3,693 women had complete data on all variables of interest; their mean (SD) age was 66 (4) years and 64% were white, 12% African-American, 14% Asian, 9% Latina and 1% mixed or other. While 28.2% presented with any detectable BAC (i.e., BAC mass &gt; 0 mg), 5.4% had an ABI &lt; 0.90. Three women had ABI&gt;1.40 and were excluded from analyses (none had BAC&gt;0). Prevalence of ABI &lt; 0.90 was 4.8% (27/2,653) in women with BAC=0 and 6.9% (72/1,040) in women with any detectable BAC. The Odds Ratio of ABI&lt;0.90 associated with any BAC was 1.39 (95% CI, 1.03-1.89) in a model adjusting for age and race/ethnicity, and was 1.38 (95% CI, 1.02-1.88) in a model with further adjustment for BMI, smoking status, diabetes, hypertension, LDL cholesterol, HDL cholesterol and hs-CRP. However, among women with any detectable BAC, standardized log_BAC mass (mg) was not significantly associated in bivariate linear regression analysis with ABI (slope=-0.0030 [SE=0.0031]; p=0.32). Our study demonstrates (for the first time) an independent association between presence of BAC and ABI indicative of PAD, with no apparent linear dose-response relationship.

Correction: Quantification of Dialytic Removal and Extracellular Calcium Mass Balance during a Weekly Cycle of Hemodialysis.

[This corrects the article DOI: 10.1371/journal.pone.0153285.].

Pedometer Measured Step Counts and Bone Mineral Density among Premenopausal Women

Pedometers have become popular physical activity measurement tools and have proven to be valid and reliable. Opportunity for bone impact comes mostly from weight bearing physical activity and is captured by the use of these devises. However, there is question about the intensity of impact needed to stimulate changes in bone tissue. Research focused on walking activity, which comprises a majority of daily physical activity for most individuals, has resulted in conflicting effects on the commencement of bone tissue remodeling. The purpose of this study was to measure pedometer based daily physical activity and determine whether these data significantly correlate with aBMD (areal bone mineral density) (g/cm2) measures among premenopausal women. A secondary purpose was to look specifically at the relationship between moderate intensity level data and aBMD. Forty-two pre-menopausal women from central Minnesota participated in the summer of 2011. Body mass index, calcium, vitamin D, total, and moderate intensity steps were tallied, and hip and lumbar spine aBMD was measured. Significant bivariate correlations (p < .05) were found between calcium and femoral, lumbar spine, and L2 aBMD measures. No correlations were found between age or vitamin D intake and aBMD measures. Significant bivariate correlations were also found between body mass index and L1, L3, L4, and total hip aBMD. No significant bivariate correlations were found between aBMD measures and total step or moderate intensity counts. Partial correlations, controlling for calcium and body mass index, did not reveal any correlations between total or moderate step counts and aBMD. It is plausible to conclude that the Omron HJ-303 pedometer may not be an appropriate tool for tracking bone building activity. Researchers need to continue to look for a consumer tool that effectively tracks this type of activity for those interested in improving bone health.

Phylloquinone Intake Is Associated with Cardiac Structure and Function in Adolescents

Associations between childhood vitamin K consumption and cardiac structure and function have not been investigated. We determined associations between phylloquinone (vitamin K-1) intake and left ventricular (LV) structure and function in adolescents. We assessed diet with three to seven 24-h recalls and physical activity (PA) by accelerometry in 766 adolescents (aged 14-18 y, 50% female, 49% black). Fat-free soft tissue (FFST) mass and fat mass were measured by dual-energy X-ray absorptiometry. LV structure [LV mass (g)/height (m)2.7 (LV mass index) and relative wall thickness] and function [midwall fractional shortening (MFS) and ejection fraction] were assessed by echocardiography. Associations were evaluated by comparing the LV structure and function variables across tertiles of phylloquinone intake. Prevalence and OR of LV hypertrophy (LV mass index >95th percentile for age and sex) were also assessed by phylloquinone tertiles. The prevalence of LV hypertrophy progressively decreased across tertiles of phylloquinone intake (P-trend < 0.01). Multinomial logistic regression-adjusting for age, sex, race, Tanner stage, systolic blood pressure, FFST mass, fat mass, socioeconomic status, PA, and intakes of energy, fiber, calcium, vitamin C, vitamin D, and sodium-revealed that compared with the highest phylloquinone intake tertile (reference group), the adjusted OR for LV hypertrophy was 3.3 (95% CI: 1.2, 7.4) for those in the lowest phylloquinone intake tertile. When LV structure variables were compared across phylloquinone intake tertiles adjusting for the same covariates, there were significant linear downward trends for LV mass index (6.5% difference, tertile 1 compared with tertile 3) and relative wall thickness (9.2% difference, tertile 1 compared with tertile 3; both P-trend ≤ 0.02). Conversely, significant linear upward trends across phylloquinone intake tertiles were observed for MFS (3.4% difference, tertile 1 compared with tertile 3) and ejection fraction (2.6% difference, tertile 1 compared with tertile 3; both P-trend < 0.04). Our adolescent data suggest that subclinical cardiac structure and function variables are most favorable at higher phylloquinone intakes.

An in silico method to predict net calcium transfer during hemodialysis.

International guidelines for chronic hemodialysis patients suggest a dialysate calcium concentration between 1.25 and 1.5 mmol/L. However, it is not certain if these dialysate calcium levels result in net calcium transfer into the patient. With ubiquitous prevalence of vascular calcification in hemodialysis patients, it is pertinent to model the mass balance of calcium during dialysis. To this end, we developed a two compartmental patient model and spatiotemporal representation of dialyzer model to investigate and quantify the calcium mass balance during dialysis. The model accounts for calcium-albumin binding and varying protein concentration; the latter accounts for the Gibbs-Donnan effect. The model simulations suggest that despite a lower dialysate calcium concentration of 1.25 mmol/L, some of our patients may be loaded with calcium during dialysis. This net calcium flux from dialysate to blood side may be a potential contributor to vascular calcification, a primary cause of cardiovascular mortality in hemodialysis patients.

Prevalence and treatment of mandibular first molar eruption disturbances

Introduction: The aim of the current study was to describe the prevalence and treatment of mandibular first molar eruption disturbances. Methods: A total of 38 mandibular first molars(M1mn) from 36 patients(17 males and 19 females; aged 9 years 2 months?35 years 10 months) were identified from the 13,391 patients that received orthodontic treatment from 1983?2012. The subjects were classified into 3 categories based on panoramic radiographic examination: impaction due to ectopic position of the tooth germ relative to the contra-side same tooth(Group 1), impaction due to obstruction of the eruption path with cyst or calcium mass (Group 2), and primary and secondary retention due to defects in the follicle or periodontal ligament(PDL; Group 3). The treatment outcomes were evaluated into four categories: no treatment(A), orthodontic traction(B), autotransplantation(C), and extraction due to orthodontic traction failure(D). Results: The prevalence rate of M1mn eruption disturbances in this sample was 0.27%. In Groups 1 and 2, most of the impacted M1mn were erupted successfully by orthodontic traction. In Group 3, most of the retained M1mn were failed to erupt and recommended for extraction. Conclusions: Treatment prognosis was favorable on Group 1 &amp; 2 than Group 3. After removing an element of the cause in case of Group 1 &amp; 2, orthodontic traction or periodic observation will be recommended.

Assessment of intradialysis calcium mass balance by a single pool variable-volume calcium kinetic model.

A reliable method of intradialysis calcium mass balance quantification is far from been established. We herein investigated the use of a single-pool variable-volume Calcium kinetic model to assess calcium mass balance in chronic and stable dialysis patients. Thirty-four patients on thrice-weekly HD were studied during 240 dialysis sessions. All patients were dialyzed with a nominal total calcium concentration of 1.50 mmol/L. The main assumption of the model is that the calcium distribution volume is equal to the extracellular volume during dialysis. This hypothesis is assumed valid if measured and predicted end dialysis plasma water ionized calcium concentrations are equal. A difference between predicted and measured end-dialysis ionized plasma water calcium concentration is a deviation on our main hypothesis, meaning that a substantial amount of calcium is exchanged between the extracellular volume and a nonmodeled compartment. The difference between predicted and measured values was 0.02 mmol/L (range -0.08:0.16 mmol/L). With a mean ionized dialysate calcium concentration of 1.25 mmol/L, calcium mass balance was on average negative (mean ± SD -0.84 ± 1.33 mmol, range -5.42:2.75). Predialysis ionized plasma water concentration and total ultrafiltrate were the most important predictors of calcium mass balance. A significant mobilization of calcium from the extracellular pool to a nonmodeled pool was calculated in a group of patients. The proposed single pool variable-volume Calcium kinetic model is adequate for prediction and quantification of intradialysis calcium mass balance, it can evaluate the eventual calcium transfer outside the extracellular pool in clinical practice.

Comparison of low-dose coronary artery calcium scoring using low tube current technique and hybrid iterative reconstruction vs. filtered back projection

IntroductionWe sought to validate whether low dose CACS CT with hybrid IR (HIR) could replace standard dose filtered back projection (FBP). MethodWe enrolled 100 patients to undergo low dose CACS CT with HIR, in addition to routine full dose FBP. ResultsNo significant difference between full and low dose CT in Agatston score 138.2±360.6 vs. 137.3±356.4 (p=0.272) or calcium mass score 19±48.3 vs. 18.7±49 (p=0.8), respectively. Bland–Altman analysis showed no systematic bias. Calcium volume difference was statistically significant 57.2±134 vs. 55.1±130.2 (p=0.001). ConclusionLow dose CT for calcium scoring with HIR enables stable CACS Agatston score and calcium mass quantification as compared to full dose FBP.

Detecting Cardiovascular Disease from Mammograms With Deep Learning.

Coronary artery disease is a major cause of death in women. Breast arterial calcifications (BACs), detected inmammograms, can be useful riskmarkers associated with the disease. We investigate the feasibility of automated and accurate detection ofBACsinmammograms for risk assessment of coronary artery disease. We develop a 12-layer convolutional neural network to discriminate BAC from non-BAC and apply a pixelwise, patch-based procedure for BAC detection. To assess the performance of the system, we conduct a reader study to provide ground-truth information using the consensus of human expert radiologists. We evaluate the performance using a set of 840 full-field digital mammograms from 210 cases, using both free-responsereceiveroperatingcharacteristic (FROC) analysis and calcium mass quantification analysis. The FROC analysis shows that the deep learning approach achieves a level of detection similar to the human experts. The calcium mass quantification analysis shows that the inferred calcium mass is close to the ground truth, with a linear regression between them yielding a coefficient of determination of 96.24%. Taken together, these results suggest that deep learning can be used effectively to develop an automated system for BAC detection inmammograms to help identify and assess patients with cardiovascular risks.

Biomass and nutrient mass of Acacia dealbata and Eucalyptus globulus bioenergy plantations

We quantified biomass and nutrient accumulation of Acacia dealbata Link and Eucalyptus globulus Labill. planted at stem densities of 5000 and 15000 ha−1 in a bioenergy plantation in Chile. We tested the hypotheses that species and stocking will not affect biomass or nutrient accumulation. Species and stocking did not affect biomass accumulation after five years; however, species and stocking did influence nutrient mass. A. dealbata had higher nitrogen mass than E. globulus for total (397 kg ha−1 more, i.e., 126% higher), foliage (188 kg ha−1, 218%), branch (55 kg ha−1, 95%), stem (120 kg ha−1, 86%), and root (34 kg ha−1, 109%) components, likely because A. dealbata fixes nitrogen. A. dealbata had lower calcium mass than E. globulus for branch (111 kg ha−1, 60%) and stem (69 kg ha−1, 39%) components. Root nitrogen and phosphorus masses and foliage, branch and root boron masses were significantly lower with a stocking density of 5000 ha−1. Low stocking produced the same amount of total biomass as high stocking for both species and would be less expensive to plant. A. dealbata had higher nitrogen mass and likely increased soil nitrogen. E. globulus had high calcium mass in the stem and branches; off-site losses could be mitigated with stem-only harvests and debarking of stems in the field. Given the rainfall patterns and water availability constraints in Chile, additional criteria including water use efficiency would be required to determine the best species for bioenergy plantations in Chile.

Computation of Calcium Score With Dual-Energy Computed Tomography: A Phantom Study.

Dual-energy computed tomography (DECT) improves material and tissue characterization compared with single-energy CT; we sought to validate coronary calcium quantification in advancing cardiovascular DECT. In an anthropomorphic phantom, agreement between measurements was excellent, and Bland-Altman analysis demonstrated minimal bias. Compared with the known calcium mass for each phantom, calcium mass by DECT was highly accurate. Noncontrast DECT yields accurate calcium measures and warrants consideration in cardiac protocols for additional tissue characterizations.

Assessment of coronary calcification using calibrated mass score with two different multidetector computed tomography scanners in the Copenhagen General Population Study

ObjectivePopulation studies have shown coronary calcium score to improve risk stratification in subjects suspected for cardiovascular disease. The aim of this work was to assess the validity of multidetector computed tomography (MDCT) for measurement of calibrated mass scores (MS) in a phantom study, and to investigate inter-scanner variability for MS and Agaston score (AS) recorded in a population study on two different high-end MDCT scanners. Materials and methodsA calcium phantom was scanned by a first (A) and second (B) generation 320-MDCT. MS was measured for each calcium deposit from repeated measurements in each scanner and compared to known physical phantom mass. Random samples of human subjects from the Copenhagen General Population Study were scanned with scanner A (N=254) and scanner B (N=253) where MS and AS distributions of these two groups were compared. ResultsThe mean total MS of the phantom was 32.9±0.8mg and 33.1±0.9mg (p=0.43) assessed by scanner A and B respectively – the physical calcium mass was 34.0mg. Correlation between measured MS and physical calcium mass was R2=0.99 in both scanners. In the population study the median total MS was 16.8mg (interquartile range (IQR): 3.5–81.1) and 15.8mg (IQR: 3.8–63.4) in scanner A and B (p=0.88). The corresponding median total AS were 92 (IQR: 23–471) and 89 (IQR: 40–384) (p=0.64). ConclusionCalibrated calcium mass score may be assessed with very high accuracy in a calcium phantom by different generations of 320-MDCT scanners. In population studies, it appears acceptable to pool calcium scores acquired on different 320-MDCT scanners.

KOMBINASI PAKAN TWO PHASE PROTEIN DENGAN ASAM SITRAT SEBAGAI ACIDIFIER TERHADAP MASSA KALSIUM DAN PERTUMBUHAN TULANG AYAM BROILER

The aim of the research was to determine bone calcium mass and growth rate of broiler chicken fed two phase dietary protein combined with citric acid as acidifier. Experimental animals were 168 broilers (84 males+84 females) MB 202strains of 7 days old with an average body weight of 186.23 ± 0.68 g. Research was arranged in a completely randomized design (CRD) with 7 treatments and 4 replications (6 birds each). The treatments were: P0 = control diet (without phase dietary protein and citric acid); P1 = two phase dietary protein without citric acid; P2 = two phase dietary protein + 0.8% citric acid of lime; P3 = two phase dietary protein + 0.4% citric acid synthetic; P4 = two phase dietary protein + 0.8% synthetic citric acid; P5 = two phase dietary protein + 1.2% synthetic citric acid; and P6 = two phase dietary protein + 1.6% synthetic citric acid. The parameters measured in the present research were bone calcium mass and growth rate (weight, length, and strength) of tibia and metatarsus of broiler chicken. The data were subjected to analysis of variance by F test followed by Duncan test (P<0.05). The results showed that two phase dietary protein combined with citric acid significantly (P<0.05) increased weight, length, and strength of tibia and metatarsus, and bone calcium mass. The conclusion is that feeding two phase dietary protein combined with citric acid as acidifier with level of 0.4-1.6% was able to increase growth rate (weight and length), calcium mass, and strength of bone in broiler chicken.

Acute calcium kinetics in haemodialysis patients.

To avoid excessive calcium loading in haemodialysis (HD) patients, current guidelines suggest a dialysate calcium concentration (dCa) of 2·5 mEq/L based on relatively stable intradialytic serum calcium levels. However, the latter do not account for possible calcium storage in acutely accessible pools. A rapidly exchangeable calcium pool located at the bone level has been previously proposed to be involved in acute (minute-to-minute) extracellular calcium regulation. To evaluate the contribution of this pool in the maintenance of serum calcium levels, acute calcium buffer capacity was assessed by measuring intradialytic dialysate-sided ionized calcium mass balance (iCaMB ) and change in extracellular fluid calcium mass in chronic HD patients using a dCa of 3·5 (n = 28) and 2·5 (n = 10) mEq/L. Serum osteocalcin, the most abundant noncollagenous bone protein, was measured before the HD session. iCaMB was invariably positive for both 2·5 and 3·5 mEq/L dCa, with a mean of 434 (±125) and 725 (±162) mg/HD, respectively (P < 0·001). Buffered intradialytic calcium load was 410 (±116) and 565 (±130) mg/HD, and acute calcium buffer capacity was 95 (±8)% and 78 (±7)% (mean values at 2·5 and 3·5 mEq/L dCa, respectively) (P < 0·001). Using 3·5 mEq/L dCa, an independent association of acute calcium buffer capacity with undercarboxylated osteocalcin (β = 0·512, P = 0·002) was demonstrated. Our data strongly suggest the existence of a rapidly exchangeable calcium pool that counteracts acute serum calcium deviations in HD patients. This study provides, for the first time, experimental evidence for the involvement of bone in acute extracellular calcium regulation in vivo.

Submillisievert coronary calcium quantification using model-based iterative reconstruction: A within-patient analysis

PurposeTo determine the effect of model-based iterative reconstruction (IR) on coronary calcium quantification using different submillisievert CT acquisition protocols. MethodsTwenty-eight patients received a clinically indicated non contrast-enhanced cardiac CT. After the routine dose acquisition, low-dose acquisitions were performed with 60%, 40% and 20% of the routine dose mAs. Images were reconstructed with filtered back projection (FBP), hybrid IR (HIR) and model-based IR (MIR) and Agatston scores, calcium volumes and calcium mass scores were determined. ResultsEffective dose was 0.9, 0.5, 0.4 and 0.2mSv, respectively. At 0.5 and 0.4mSv, differences in Agatston scores with both HIR and MIR compared to FBP at routine dose were small (−0.1 to −2.9%), while at 0.2mSv, differences in Agatston scores of −12.6 to −14.6% occurred. Reclassification of risk category at reduced dose levels was more frequent with MIR (21–25%) than with HIR (18%). ConclusionsRadiation dose for coronary calcium scoring can be safely reduced to 0.4mSv using both HIR and MIR, while FBP is not feasible at these dose levels due to excessive noise. Further dose reduction can lead to an underestimation in Agatston score and subsequent reclassification to lower risk categories. Mass scores were unaffected by dose reductions.

CT calcium scoring. History, current status and outlook.

Cardiovascular risk assessment has assumed a prominent role in the course of preventive care of all adults. Traditionally cardiovascular risk assessment has been performed using risk factors including gender, age, smoking history, lipid status, diabetes status, and family history. Increasingly, imaging has been deployed to directly detect coronary atherosclerotic disease. Quantification of coronary calcium (e.g., Agatston method, calcium mass and volume) is readily detected using helical CT scanners. Large multicenter cohort studies have enabled a better understanding of the relevance of coronary calcium detection. The purpose of this review is to review the methods for quantification of coronary artery calcium, as well as to present current and future perspectives on calcium scoring for cardiovascular risk stratification.