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Computed tomography in the emergency department
Published in Pim J de Feyter, Gabriel P Krestin, Filippo Cademartiri, Carlos van Mieghem, Bob Meijboom, Nico Mollet, Koen Nieman, Denise Vrouenraets, Computed Tomography of the Coronary Arteries, 2008
Pim J de Feyter, Gabriel P Krestin, Filippo Cademartiri, Carlos van Mieghem, Bob Meijboom, Nico Mollet, Koen Nieman, Denise Vrouenraets
The presence of coronary calcification as assessed by CT may increase the likelihood that acute chest pain is caused by coronary artery disease. Younger patients with positive calcium scores (Agatston score more than zero) require further in-hospital diagnostic work-up, whereas in patients with absence of detectable coronary calcification the likelihood of a flow-limiting coronary stenosis is very low, and discharge of the patient may be safe (Figures 17.1–17.3)3. Calcium scoring performed in patients with acute chest pain presenting at an emergency department may also predict future adverse coronary events, including sudden cardiac death and non-fatal myocardial infarction. A positive calcium scoring scan is associated with a higher annualized event rate, while a negative scan is associated with a very low risk of future adverse coronary events (Table 17.1)4,5 (Figure 17.4). To date, only limited data are available on the combined assessment of CT calcium scoring and CT coronary angiography in the setting of the evaluation of acute chest pain in an emergency department. However, it seems reasonable to assume that the combined information would be clinically relevant.
Cardiac CT and MRI: State of the Art
Published in Phillip M. Boiselle, Charles S. White, New Techniques in Cardiothoracic Imaging, 2007
Much of the investigative work on calcium scoring has been reported with EBT. The most widely used quantitative method of assessing coronary calcium is the Agatston score. This score represents the product of the number of pixels with calcification and the density weighting of the calcification on a sliding scale (14). A threshold of 130 HU is used to designate calcification (Fig. 3). The Agatston score is calculated by means of standard software and results are normalized for age and gender with a percentile rank generated based on a large database. The Agatston score remains in wide use because of its incorporation in multiple large population-based studies (15).
Recent developments and applications of hybrid imaging techniques
Published in Yi-Hwa Liu, Albert J. Sinusas, Hybrid Imaging in Cardiovascular Medicine, 2017
Piotr J. Slomka, Daniel S. Berman, Guido Germano
Typically, in current practice with hybrid systems, the CAC scan is acquired separately, immediately before the PET/CT scan (Di Carli, Dorbala, and Hachamovitch 2006). This regimen with separate CT CAC and attenuation scans increases the radiation dose to the patient (Kim, Einstein, and Berrington de Gonzalez 2009) and lengthens the overall scan protocol. However, it should be possible to utilize the CT calcium scans for attenuation correction and therefore eliminate the need for the CT scans on a hybrid PET/CT or SPECT/CT scanner. Vendors are developing manual or even automated tools for this purpose, as described in the previous section. In Figure 12.16, we show a screen snapshot of the software utility from one vendor demonstrating the user interface for manual realignment of calcium scan with SPECT for the purposes of attenuation correction. This technique has been successfully applied in SPECT/CT (Schepis et al. 2007b) and PET/CT hybrid imaging (Burknard et al. 2010). In both of these studies, the correlation between the myocardial perfusion results corrected for attenuation with calcium scan and with standard CT attenuation correction scan was excellent in all regions of the myocardium. Conversely, it may be also possible to estimate coronary calcium from nongated low-dose CT attenuation maps (Einstein et al. 2010; Mylonas et al. 2012), even if the quality of the CT maps used for attenuation correction is lower than that of the standard CT calcium scan. Studying 492 patients from three centers, Einstein et al. have demonstrated that coronary artery calcifications can be visually assessed from low-dose CT attenuation correction scans for PET/CT and SPECT/CT with high agreement for the Agatston score (Einstein et al. 2010). Weighted kappa was 0.89 (95% confidence interval [CI]: 0.88–0.91). Mylonas et al. demonstrated the quantitative assessment of calcium score from the CT attenuation maps with standard calcium score maps in 92 patients. The interclass correlation between the calcium score CT attenuation maps and calcium score CT was 0.953 (95% CI: 0.930–0.96) (Mylonas et al. 2012). Further research is warranted to standardize and simplify the hybrid cardiac PET/CT protocols, so that reliable PET or SPECT attenuation correction and calcium measurements could be obtained from a single CT scan on a hybrid scanner or even obtained using a standalone CT scan.
Longitudinal blood pressure patterns and cardiovascular disease risk
Published in Annals of Medicine, 2020
Joel Nuotio, Karri Suvila, Susan Cheng, Ville Langén, Teemu Niiranen
In addition, the use of long-term BP trajectories for CVD risk prediction has also been studied in younger populations. As clinical CVD events are rare in younger age groups, surrogate measures for CVD risk have to be used instead. In the CARDIA study, five BP trajectories were characterised over a 25-year period among 4,681 participants aged 18–30 years at baseline [25]. Data was collected on eight time points, and all participants had at least three BP measurements. Presence of coronary calcification greater or equal to Agatston score of 100 Hounsfield units, a strong predictor of incident coronary heart disease, was used as a marker of subclinical atherosclerosis [48]. The results indicated that participants with elevated BP levels from youth throughout middle age and those who had steep increases in BP levels over time had the greatest odds of having subclinical CVD. These associations remained significant after adjusting for conventional CVD risk factors and even after further adjustments for baseline and 25-year follow-up BP level. These findings demonstrate that also in younger populations, long-term BP levels enhance the prognostication of future coronary artery calcification beyond the consideration of single BP measurements. In addition, BP trajectories have also been associated with other forms of target-organ damage such as left ventricular hypertrophy and subclinical renal damage [49–52].
Current and future applications of CT coronary calcium assessment
Published in Expert Review of Cardiovascular Therapy, 2018
Christian Tesche, Taylor M. Duguay, U. Joseph Schoepf, Marly van Assen, Carlo N. De Cecco, Moritz H. Albrecht, Akos Varga-Szemes, Richard R. Bayer, Ullrich Ebersberger, John W. Nance, Christian Thilo
The calcium mass score was introduced by Hong et al. in 2002 to calculate the true mass of coronary calcium [27]. Agatston score and volume score serve as indirect measures of coronary calcification and calcium burden as they depend on input factors like calcium density and threshold density. The calcium mass score allows for the calculation of absolute values of calcium mass. However, the measurement of mass scores requires a dedicated scanning protocol and phantom-based calibration and correction factors [33–35]. A thorax-phantom containing different concentrations of calcium hydroxyapatite needs to be placed beneath the patient’s thorax to calibrate the segmented coronary calcium. Although this method is technically advanced with high reproducibility of calcium values, the complexity of performance has prevented its implementation into routine clinical practice. A case example of CAC mass scoring is displayed in Figure 1.
Advances in understanding of mechanisms related to increased cardiovascular risk in COPD
Published in Expert Review of Respiratory Medicine, 2021
Paola Rogliani, Beatrice Ludovica Ritondo, Rossella Laitano, Alfredo Chetta, Luigino Calzetta
Two additional non-validated methods to detect CAC in COPD patients have been identified: the Agatston score and Weston score [91]. The Agatston score combines plaque volume and density, weighted more toward increased plaque density, conversely the Weston score is a visual estimate for the calcification volume in major coronary arteries and it is considered a strong predictor of CVD since it is specifically focused on the size of the lesion rather than the density. The Weston score is a highly reliable, easily applicable, and inexpensive tool, although a main limitation of it is the high expertise required for the visual scoring system [91].