scholarly journals Dose Reduction in Coronary Artery Calcium Scoring Using Mono-Energetic Images from Reduced Tube Voltage Dual-Source Photon-Counting CT Data: A Dynamic Phantom Study

Diagnostics ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2192
Author(s):  
Niels R. van der Werf ◽  
Margo van Gent ◽  
Ronald Booij ◽  
Daniel Bos ◽  
Aad van der Lugt ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Radiation Dose ◽  
Coronary Artery Calcium ◽  
Standard Dose ◽  
Photon Counting ◽  
High Density ◽  
Agatston Score ◽  
Tube Voltage ◽  
Heart Rates ◽  
Ct Data

In order to assess coronary artery calcium (CAC) quantification reproducibility for photon-counting computed tomography (PCCT) at reduced tube potential, an anthropomorphic thorax phantom with low-, medium-, and high-density CAC inserts was scanned with PCCT (NAEOTOM Alpha, Siemens Healthineers) at two heart rates: 0 and 60–75 beats per minute (bpm). Five imaging protocols were used: 120 kVp standard dose (IQ level 16, reference), 90 kVp at standard (IQ level 16), 75% and 45% dose and tin-filtered 100 kVp at standard dose (IQ level 16). Each scan was repeated five times. Images were reconstructed using monoE reconstruction at 70 keV. For each heart rate, CAC values, quantified as Agatston scores, were compared with the reference, whereby deviations >10% were deemed clinically relevant. Reference protocol radiation dose (as volumetric CT dose index) was 4.06 mGy. Radiation dose was reduced by 27%, 44%, 67%, and 46% for the 90 kVp standard dose, 90 kVp 75% dose, 90 kVp 45% dose, and Sn100 standard dose protocol, respectively. For the low-density CAC, all reduced tube current protocols resulted in clinically relevant differences with the reference. For the medium- and high-density CAC, the implemented 90 kVp protocols and heart rates revealed no clinically relevant differences in Agatston score based on 95% confidence intervals. In conclusion, PCCT allows for reproducible Agatston scores at a reduced tube voltage of 90 kVp with radiation dose reductions up to 67% for medium- and high-density CAC.

scholarly journals False-Positive Calcifications and Radiation Dose in Coronary Artery Calcium Scoring Using Iterative Reconstruction on The Basis of a Noise Threshold

2019 ◽  
pp. 1-6
Author(s):  
M. Garmer ◽  
C. Lehrenfeld ◽  
F. Metz ◽  
O. Klein-Wiele ◽  
B. Brandts ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Coronary Artery Calcium ◽  
False Positive ◽  
Standard Dose ◽  
Ct Scanner ◽  
Dose Length Product ◽  
Noise Threshold ◽  
Dose Modulation

Radiation dose from cardiac CT seems to be underestimated. To determine the effect of iterative reconstruction in coronary artery calcium (CAC) scoring on false positive lesions and radiation dose using a noise threshold. Noise-based thresholds have been previously suggested to reduce false positive lesions in lower dose protocols. In 388 matched pairs of patients we performed CAC scoring using a 320-row CT-scanner with standard dose filtered backprojection (FBP) and lower dose iterative reconstruction (IR). Dose modulation was based on a noise threshold. Radiation dose, image quality and extent of false-positive calcifications were obtained. IR versus FBP showed a reduced dose length product (median 61 versus 74; p< 0.001), less noise (median SD 14.71 versus 18.07; p< 0.001) and higher signal-to-noise ratio (median 4.01 versus 3.14; p< 0.001). Using IR in 388 patients, a low quantity of false-positive calcifications was found in 302 patients, a moderate quantity in 76 patients and a high quantity in 10 patients, while using FBP, the corresponding distribution of patients was 79, 175 and 134 (p<0.001). In this clinical setting we confirm the observation of a phantom study that CAC scoring using iterative reconstruction and a noise threshold is effective for the reduction of radiation dose.

scholarly journals Diagnostic and prognostic value of coronary artery calcium score of zero: is it time for guidelines to change?

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
E Arbas Redondo ◽  
D Tebar Marquez ◽  
I.D Poveda Pinedo ◽  
R Dalmau Gonzalez-Gallarza ◽  
S.C Valbuena Lopez ◽  
...  
Keyword(s):  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Coronary Angiography ◽  
Coronary Artery Calcium ◽  
Cardiac Ct ◽  
Invasive Coronary Angiography ◽  
Agatston Score ◽  
Non Invasive ◽  
Artery Disease

Abstract Introduction Cardiac computed tomography (CT) use has progressively increased as the preferred initial test to rule out coronary artery disease (CAD) when clinical likelihood is low. Coronary artery calcium (CAC) detected by CT is a well-established marker for cardiovascular risk. However, it is not recommended for diagnosis of obstructive CAD. Absence of CAC, defined as an Agatston score of zero, has been associated to good prognosis despite underestimation of non-calcified plaques. Purpose To evaluate whether zero CAC score could help ruling out obstructive CAD in a safely manner. Methods Observational study based on a prospective database of patients (pts) referred to cardiac CT between 2017 and 2019. Pts with an Agatston score of zero were selected. Results We included 176 pts with zero CAC score and non-invasive coronary angiography performed. The median duration of follow-up was 23.9 months. Baseline characteristics of the population are shown in Table 1. In 117 pts (66.5%), cardiac CT was indicated as part of their chest pain evaluation. Mean age was 57.2 years old, 68.2% were women and only and 9.4% were active smokers. Normal coronary arteries were found in 173 pts (98.3%). Obstructive CAD, defined as ≥50% luminal diameter stenosis of a major vessel, was present in 1/176 (0.6%); while non-obstructive atherosclerotic plaques were found in 2 pts (1.1%). During follow-up, one patient died of out-of-hospital cardiac arrest. None either suffered from myocardial infarction or needed coronary revascularization. Conclusions In our cohort, a zero CAC score detected by cardiac CT rules out obstructive coronary artery disease in 98.3%, with only 1.7% of non-calcified atherosclerosis plaques and 0.6% of major adverse events. Although further research on this topic is needed, these results support the fact that non-invasive coronary angiography could be avoided in patients with low clinical likelihood of CAD and zero CAC score, facilitating the management of the increasing demand for coronary CT and reduction of radiation dose. Funding Acknowledgement Type of funding source: None

scholarly journals Evaluation of an AI-based, automatic coronary artery calcium scoring software

2019 ◽  
Vol 30 (3) ◽  
pp. 1671-1678 ◽  
Author(s):  
Mårten Sandstedt ◽  
Lilian Henriksson ◽  
Magnus Janzon ◽  
Gusten Nyberg ◽  
Jan Engvall ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Coronary Artery ◽  
Coronary Artery Calcium ◽  
Rank Test ◽  
Agatston Score ◽  
Risk Category ◽  
Automatic Method ◽  
Calcium Scoring ◽  
Excellent Correlation ◽  
Automatic Software

Abstract Objectives To evaluate an artificial intelligence (AI)–based, automatic coronary artery calcium (CAC) scoring software, using a semi-automatic software as a reference. Methods This observational study included 315 consecutive, non-contrast-enhanced calcium scoring computed tomography (CSCT) scans. A semi-automatic and an automatic software obtained the Agatston score (AS), the volume score (VS), the mass score (MS), and the number of calcified coronary lesions. Semi-automatic and automatic analysis time were registered, including a manual double-check of the automatic results. Statistical analyses were Spearman’s rank correlation coefficient (⍴), intra-class correlation (ICC), Bland Altman plots, weighted kappa analysis (κ), and Wilcoxon signed-rank test. Results The correlation and agreement for the AS, VS, and MS were ⍴ = 0.935, 0.932, 0.934 (p < 0.001), and ICC = 0.996, 0.996, 0.991, respectively (p < 0.001). The correlation and agreement for the number of calcified lesions were ⍴ = 0.903 and ICC = 0.977 (p < 0.001), respectively. The Bland Altman mean difference and 1.96 SD upper and lower limits of agreements for the AS, VS, and MS were − 8.2 (− 115.1 to 98.2), − 7.4 (− 93.9 to 79.1), and − 3.8 (− 33.6 to 25.9), respectively. Agreement in risk category assignment was 89.5% and κ = 0.919 (p < 0.001). The median time for the semi-automatic and automatic method was 59 s (IQR 35–100) and 36 s (IQR 29–49), respectively (p < 0.001). Conclusions There was an excellent correlation and agreement between the automatic software and the semi-automatic software for three CAC scores and the number of calcified lesions. Risk category classification was accurate but showing an overestimation bias tendency. Also, the automatic method was less time-demanding. Key Points • Coronary artery calcium (CAC) scoring is an excellent candidate for artificial intelligence (AI) development in a clinical setting. • An AI-based, automatic software obtained CAC scores with excellent correlation and agreement compared with a conventional method but was less time-consuming.

Abstract P104: Higher Leptin Levels Are Associated With Increased Odds Of Coronary Artery Calcium Progression: The Multi-ethnic Study Of Atherosclerosis

Circulation ◽  
2021 ◽  
Vol 143 (Suppl_1) ◽  
Author(s):  
Bhavya Varma ◽  
Oluseye Ogunmoroti ◽  
Chiadi Ndumele ◽  
Di Zhao ◽  
Moyses Szklo ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Coronary Artery Calcium ◽  
Cardiac Ct ◽  
Subclinical Atherosclerosis ◽  
Community Dwelling ◽  
Ct Scans ◽  
Agatston Score ◽  
Cvd Risk ◽  
Ethnic Study ◽  
History Of

Background: Adipokines are secreted by adipose tissue, play a role in cardiometabolic pathways, and have differing associations with cardiovascular disease (CVD). Coronary artery calcium (CAC) and its progression indicate subclinical atherosclerosis and prognosticate CVD risk. However the association of adipokines with CAC progression is not well established. We examined the association of adipokines with the odds of a history of CAC progression in the Multi-Ethnic Study of Atherosclerosis (MESA). Methods: We performed an analysis of 1,904 community dwelling adults free of clinical CVD in MESA. Participants underwent measurement of serum adipokines [leptin, resistin and adiponectin] at visits 2 or 3 (randomly assigned) and a contemporaneous cardiac CT scan at same visit. Participants also had a prior cardiac CT at visit 1, at a median of 2.4 years earlier. On both CTs, CAC was quantified by Agatston score. We defined a history of CAC progression between the CT scans at visit 1 and at visit 2 or 3 as those with >0 Agatston units of change per year (and compared to those with ≤0 units of change per year). We used logistic regression to examine the odds of having a history of CAC progression by adipokine tertiles using progressively adjusted models. Results: The mean participant age was 65 (10) years; 50% were women, 40% White, 13% Chinese, 21% Black and 26% Hispanic. The prevalences of CAC at visits 1 and 2/3 were 49% and 58%, respectively. There were 1,001 (53%) who had CAC progression between the 2 CT scans. In demographic-adjusted models (model 1, Table), higher leptin and lower adiponectin were associated with increased odds of prior CAC progression. In models fully adjusted for BMI and other CVD risk factors (model 3), only the highest tertile of leptin remained associated with a greater odds of prior CAC progression [OR 1.55 (95% CI 1.04, 2.30)]. Conclusions: Higher leptin levels were independently associated with a history of CAC progression. Atherosclerosis progression may be one mechanism through which leptin confers increased CVD risk

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