Dual-layer spectral detector CT to study the correlation between pericoronary adipose tissue and coronary artery stenosis

Background To investigate the relationship of pericoronary adipose tissue (PCAT) with coronary artery stenosis using dual-layer spectral detector CT (SDCT). Methods 99 patients were retrospectively divided into normal group, non-significant stenosis group and significant stenosis group (n = 33 in each group). Fat attenuation index (FAI) 40kev, spectral curve slope (λHU), effective atomic number (Eff-Z) and epicardial fat volume (EFV) were quantitatively evaluated of the narrowest part of the lesion tissue by SDCT. Results There were significant differences in PCAT parameters on SDCT (FAI40keV, λHU, Eff-Z and EFV) among the three groups (P < 0.05). FAI40keV, λHU, and Eff-Z in significant stenosis group were statistically different from those in normal group and non-significant stenosis group (P < 0.05). FAI40keV, λHU, and Eff-Z in non-significant stenosis group were statistically different from significant stenosis group (P < 0.05). EFV in normal group were significantly lower in non-significant stenosis group and significant stenosis group (P < 0.001). Univariate and multivariate logistic regression analyses identified FAI40keV (OR = 1.50, 95%CI 1.01 to 1.09) and λHU (OR = 6.81, 95%CI 1.87 to 24.86) as independent predictors of significant stenosis. FAI40keV and λHU had quite good discrimination, with an AUC of 0.84 and 0.80 respectively. Conclusion FAI40keV, λHU, and Eff-Z on SDCT in significant stenosis group were significantly different from normal and non-significant stenosis group while EFV in normal group were significantly different from non-significant stenosis group and significant stenosis group. FAI40kev and λHU were risk factors for significant stenosis.

Pericoronary adipose tissue attenuation index (FAI) – a new imaging biomarker and its diagnostic and prognostic utility: a systematic review and meta-analysis

Background Pericoronary fat attenuation index (FAI) on coronary computed tomography angiography (CCTA) imaging has been proposed as a sensitive marker of coronary vascular inflammation with prognostic value for major cardiovascular events. To date though there is no systematic review of the published literature and no meta-analyzed data of previously published results. Methods We performed a systematic review and meta-analysis according to the PRISMA guidelines. We systematically explored published literature in MEDLINE (Pubmed) before February 1, 2021 for studies assessing FAI in both diagnostic and prognostic clinical settings in patients with or without cardiovascular disease. The primary outcome was the mean difference in FAI attenuation between stable and unstable coronary plaques. The secondary outcome was the hazard ratio of high FAI values for future cardiovascular events. We calculated I2 to test heterogeneity. We used random effects modelling for the meta-analyses to assess the primary and secondary outcome. Results In total, 16 studies and 6,944 patients were included in this meta-analysis. FAI was significantly higher in unstable compared to stable plaques with a mean difference of 4.07 HU (95% CI: 1.10–7.89, I2=88%). Higher FAI values offered incremental prognostic value for major cardiovascular events (MACE) in studies with prospective follow-up (HR=3.29, 95% CI= 1.88–5.76, I2=75%). Conclusion FAI is a promising imaging biomarker that may be successfully be used for detection of coronary inflammation, discrimination between stable and unstable plaques and prognosis of future MACE. There is undeniable need of further studies to establish the utility of this biomarker in clinical practice in order to improve coronary plaque discrimination and cardiovascular risk prognostication. FUNDunding Acknowledgement Type of funding sources: None.

Association of Pericoronary Adipose Tissue Quality Determined by Dual-Layer Spectral Detector CT With Severity of Coronary Artery Disease: A Preliminary Study

Background: Pericoronary adipose tissue (PCAT) is considered as a source of inflammatory mediators, leading to the development of coronary atherosclerosis. The study aimed to investigate the correlation between PCAT quality derived from dual-layer spectral detector CT (SDCT) and the severity of coronary artery disease (CAD), and whether PCAT parameters were independently associated with the presence of CAD.Materials and Methods: A total of 403 patients with symptoms of chest pain who underwent SDCT were included. PCAT quality including fat attenuation index (FAI) measured from conventional polychromatic CT images (FAI120kvp) and spectral virtual mono-energetic images at 40 keV (FAI40keV), slope of spectral HU curve (λHU), and effective atomic number (Eff-Z) were measured around the lesions representing the maximal degree of vascular stenosis in each patient. Meanwhile, overall epicardial adipose tissue (EAT) attenuation was acquired in the conventional polychromatic energy imaging.Results: FAI40keV, λHU, Eff-Z, and FAI120kvp increased along with the degree of CAD in general and were superior to the overall EAT attenuation for detecting the presence of CAD. Multivariate logistic regression analysis indicated that FAI40keV was the most powerful independent indicator (odds ratio 1.058, 95% CI 1.044–1.073; p &lt; 0.001) of CAD among these parameters. Using an optimal cut-off (−131.8 HU), FAI40keV showed higher diagnostic accuracy of 80.6% compared with the other parameters.Conclusions: These preliminary findings suggest that FAI40keV on SDCT may be an appealing surrogate maker to allow monitoring of PCAT changes in the development of CAD.

Aging Characteristics of Asphalt Binder under Strong Ultraviolet Irradiation in Northwest China

Asphalt pavement is significantly affected by ultraviolet (UV) aging. Therefore, the establishment of an asphalt UV aging evaluation system is desirable for highway construction in areas which experience strong UV radiation. In this study, Dunhuang City in Gansu Province (northwest China) was used as the research site. Base and SBS modified asphalts were selected, and their performance changes before and after UV aging were studied. An asphalt UV aging evaluation system was established, including the conditions for an indoor, accelerated UV aging test as well as evaluation indicators. The results showed that the adverse effect of UV aging on asphalt performance was greater than that of RTFOT and PAV, and that the low-temperature performance of asphalt degraded most rapidly. SBS modified asphalt was more resistant to UV aging than base asphalt, while 60/80 pen grade base asphalt was found to be unsuitable for use on pavements which are exposed to strong UV radiation. The residual penetration, penetration attenuation index at 25 °C, and residual ductility of the asphalt were used as indicators to characterize the aging of asphalt, while the fracture energy method was used as a supplementary evaluation method.

Assessment of Coronary Inflammation by Pericoronary Fat Attenuation Index in Clinically Suspected Myocarditis with Infarct-Like Presentation

Background: The pathophysiology of angina-like symptoms in myocarditis is still unclear. Perivascular fat attenuation index (pFAI) by coronary computed tomography angiography (CCTA) is a non-invasive marker of coronary inflammation (CI) in atherosclerosis. We explored the presence of CI in clinically suspected myocarditis with infarct-like presentation. Methods: We retrospectively included 15 consecutive patients (67% male, age 30 ± 10 years) with clinically suspected infarct-like myocarditis who underwent CCTA to rule out coronary artery disease. Right coronary artery (RCA) pFAI mean value was compared with that of healthy volunteers. Results: Mean RCA pFAI value was −92.8 ± 8.4 HU, similar to that of healthy volunteers (−95.2 ± 6.0, p = 0.8). We found no correlation between RCA pFAI mean values and peak Troponin I (r = −0.43, p = 0.11) and C-reactive protein at diagnosis (r = −0.25, p = 0.42). Patients with higher pFAI values showed higher biventricular end-systolic volumes (ESV) (p = 0.038 for left and p = 0.024 for right ventricle) and lower right ventricular ejection fraction (RVEF) (p = 0.038) on cardiovascular magnetic resonance. Conclusions: In clinically suspected myocarditis with infarct-like presentation, RCA pFAI values are lower than those validated in atherosclerosis. The correlation between higher pFAI values, higher biventricular ESV and lower RVEF, may suggest a role of pFAI in predicting non-atherosclerotic CI (i.e., infective/immune-mediated “endothelialitis”).

Coronary Inflammation Assessed by Perivascular Fat Attenuation Index in Patients with Psoriasis: A Propensity Score-Matched Study

<b><i>Objectives:</i></b> This study aimed to evaluate coronary inflammation by measuring the perivascular fat attenuation index (FAI) and quantify the atherosclerosis burden in patients with psoriasis and control individuals without psoriasis based on coronary computed tomography angiography (CCTA) images. <b><i>Methods:</i></b> A total of 98 consecutive patients with psoriasis (76 male [77.6%], aged 56.5 years, range 45.5–65.0) were recruited, and 196 patients (157 male [80.1%]; aged 54.6 ± 14.1 years) without established cardiovascular disease (CVD) who underwent CCTA within the same period were enrolled in the control group. Coronary plaque burden was quantified using the computed tomography-adapted Leaman score (CT-LeSc), and the FAI surrounding the proximal of three main epicardial vessels was measured to represent coronary inflammation. <b><i>Results:</i></b> Patients with psoriasis and the control subjects were well matched in CVD risk factors (all <i>p</i> &#x3e; 0.05). Psoriasis patients had a greater overall CT-LeSc (5.86 vs. 4.69, <i>p</i> = 0.030) and lower perivascular FAI (−80.19 ± 7.48 vs. −78.14 ± 7.81 HU, <i>p</i> &#x3c; 0.001). A similar result was found upon comparing psoriasis patients without biological or statin therapy with non-psoriasis individuals without statin treatments. Furthermore, the psoriasis group had a higher prevalence of non-calcified plaques (30.3% in the psoriasis group vs. 20.1% in the control subjects, <i>p</i> = 0.001). No difference in perivascular FAI on either calcified and mixed plaques or non-calcified plaques between the two groups was found. <b><i>Conclusion:</i></b> Patients with psoriasis have a higher atherosclerotic burden as quantified by CT-LeSc and less coronary inflammation as detected by perivascular FAI around the most proximal of the three major epicardial vessels. The usefulness of perivascular FAI for evaluating coronary inflammation in patients with chronic low-grade inflammatory disease such as psoriasis should be verified.

Water Suspension and its Effect on Total Light Attenuation in Lake Waters

The paper presents the data obtained by the authors in 2012-2021 during field trips to freshwater reservoirs of Altai Krai. According to hydro-optical measurements, values of light attenuation index in the range of 400-800 nm calculated using the natural logarithm varied greatly within 2.3-19.7 m-1 and 2.9-35.0 m-1 in the surface layer of lakes Lapa and Krasilovskoye during the study period. The relative spectral contribution of water suspension and contributions of yellow matter, chlorophyll, and pure water constituents at wavelengths of 430, 550, and 670 nm were estimated to assess the optical effect of water suspension on the total light attenuation index. The calculation results demonstrated that water suspension had the maximum effect on light attenuation in waters of eutrophic lake Lapa during the autumn-winter period. The maximum effect at all three wavelengths was observed in autumn of 2015, and the contribution of water suspension to light attenuation reached 88.5%, whereas its minimum (1.8-2.4 %) was recorded in 2017. The maximum contribution of water suspension on light attenuation in waters of eutrophic-hypereutrophic lake Krasilovskoye slightly exceeded the value of 70% during the winter of 2014. The next maximums were revealed during the spring of 2014 and had values of 71.3 % at λ =430 nm and 71.1 % at λ =550 nm. Optical microscopy was used to estimate the size and concentration of water suspense particles. The average weighted value of radius for water suspense particles in the surface layer of lakes Lapa and Krasilovskoye was found to be 1.2 and 1.4 microns, respectively. The average particulate count for water suspense during the observation period varied in the range of 0.2·106 cm-3-14.7·106 cm-3 with values of 3.3·106 cm-3 for lake Lapa and 3.0·106 cm-3 for lake Krasilovskoye.