Attenuation Index Research Articles

Body composition parameter as risk predictor in metastatic renal cell carcinoma (mRCC)?

e16506 Background: Imaging-derived data for patient’s (pts) prognostication in advanced/metastatic (m)RCC remains scarce. Recently, imaging body composition parameters such as muscle radiation attenuation (MA) and skeletal muscle index (SMI) as prognostic markers for cancer became a matter of interest. Here, impact of MA and SMI in mRCC pts, treated in our tertiary center, were retrospectively investigated. Methods: During the observation period 01/03 – 05/16, 401 pts mRCC receiving first line medical treatment were identified and analyzed. Pts were included for MA- and SMI-analysis based on Computed tomography (CT) scan data and recorded height and bodyweight, respectively. SMI and MA were assessed by a self-designed software-module using MeVisLab. SMI- and MA-subgroups were established by cutoff points, established using an optimum risk stratification method. Descriptive statistics and overall survival (OS) with Log-rank analysis were administered. Parameters with differences in MA-subgroups (p < 0.2) were analyzed with univariable and multivariable Cox-Regression, once p < 0.2 at each subsequent step. Results: 133 pts were eligible for MA-, 123 pts for SMI-analysis. The median age was 62 (range: 39-84) years, and 65.4% of pts showed an ECOG = 0. 87/133 (65.4%) and 71/123 (57.7%) pts showed low MA and low SMI, respectively. At time of mRCC diagnosis pts with low MA were significantly older (mean: 65 vs. 58 years, p < 0,001), while T-, N-, and M-status, as well as MSKCC did not differ. Low MA was associated with a median OS of 27 (95% CI: 17,1-36.3) mo., compared to 60 (95% CI: 36.7-83.3) mo. for high MA (Log-Rank p = 0.001). Multivariable analysis identified low MA as an independent risk factor for OS (HR 2.07; 95% CI 1.24-3.48; p = 0.006). SMI did not reach significance (p = 0.1) (Tab.1). Conclusions: Here, MA provided a robust prognostic parameter regarding OS in mRCC pts. Interestingly, SMI showed no prognostic impact. CT-derived MA could be a promising addition to existing risk-scores. Further research is needed to validate these finding.[Table: see text]

C47 CORO–CT PLAQUE ANALYSIS IN ASSESSMENT OF CARDIOVASCULAR RISK

Abstract Background Computed tomographic (CT) coronary angiography represents a non–invasive approach to assess plaque characteristics that provides information to change treatment of coronary artery disease (CAD) and to asses risk stratification. Purpose Analyze the differences in plaque composition between patients with different plaque features: soft unstable plaques, hard stable plaques and no plaques; identify whether there is a relationship between the plaque density and the pericoronary fat attenuation index (pFAI). Materials and methods: 372 patients retrospectively analyzed who underwent CTCA for exclusion of CAD. They were divided into three groups: 37 (10%) patients with high attenuated plaques (> 60HU), 137 (37%)with low attenuated plaques (<29 HU and a volume of at least 15 mm3 and/or 30–59 HU with a volume greater than 52 mm3) and 198 (53%) patients without significant CAD. For each patients we collected clinical, radiological and follow–up data. Results and Discussion Low–attenuated plaques are significantly associated with older age, male sex, dyslipidemia and diabetes mellitus (p < 0.001). Higher values of pFAI were more present in patients with soft plaques than in those with stable plaques and without plaques (p = 0.005). It was also found that soft plaques were present in more CA segments compared to stable plaques. Overall volume of soft plaque appears greater than hard plaques and mainly localized in the anterior descendant coronary artery with higher stenosis values (p < 0.001). Presence of plaques with soft or high–risk features predisposes significantly and independently (p < 0.001) to a composite outcome (death, in–hospital admissions for percutaneous angioplasty or by–pass procedures) at the follow up. Conclusions Coronary plaque analysis showed a good correlation between high–risk plaques and pFAI, supporting the hypothesis that the presence of high–risk plaques can be correlated to inflammatory burden. Furthermore, the presence of high risk plaques predispose to death or hospitalization for coronary intervention.

Experimental Study on Dynamic Response and Damage Evolution of Coal under Shocks by Multiple High-Pressure Air Blasting

To explore the dynamic response and damage evolution of coal under multiple high-pressure air blasting (HPAB), simulated coal specimens were used in the HPAB experiments, and the variation laws of stress field, vibration field, damage field, and cumulative fracture failure process in specimens were analyzed from a macro point of view. A scanning electron microscope (SEM) and mercury intrusion porosimetry (MIP) were used to observe the pore distribution near the blasthole of the specimen and analyze the variation law of pore structure parameters under multiple HPAB from the microscopic point of view. The test results show that (1) the stress wave generated by HPAB has a great impact on the near zone. After multiple HPAB, the damage value at the place 50 mm away from the blasthole increases by 3.91 times compared with the one shock from HPAB, and the strain peak and vibration velocity are reduced by 17.86% and 63.05%, respectively. With the increase of distance, the internal damages of the specimens in the middle and far zones are mainly driven by the stress wave and the high-pressure air, and the strain peak, vibration velocity, and damage degree gradually decrease. (2) With the increase of shock times in HPAB tests, the stress wave attenuation index decreases at first and then increases, and the damages degree of the middle and far zones increase slowly in the first few shocks and then increase rapidly. The site coefficient ( k ) shows an overall decreasing trend, whereas the attenuation coefficient ( α ) tends to increase. (3) The multiple HPABs have a great impact on the pore structure of the specimens. Compared with unshocked specimen, the cumulative mercury injection and pore volume increased by 152.04% and 135.05%, respectively. The number of connecting pores with large pore diameter is significantly increased. The multiple HPAB can effectively improve the pore and fracture structure in the specimens and form a relatively developed fracture network channel. The study results have certain guiding value for solving practical engineering problems of low extraction efficiency in low permeability coal seams.

Identification of patients with acute myocardial infarction based on coronary CT angiography: the value of pericoronary adipose tissue radiomics.

To determine whether radiomics analysis of pericoronary adipose tissue (PCAT) captured by coronary computed tomography angiography (CCTA) could discriminate acute myocardial infarction (MI) from unstable angina (UA). In a single-center retrospective case-control study, patients with acute MI (n = 105) were matched to patients with UA (n = 105) and all patients were randomly divided into training and validation cohorts with a ratio of 7:3. Fat attenuation index (FAI) and PCAT radiomics features selected by Max-Relevance and Min-Redundancy (mRMR) and least absolute shrinkage and selection operator (LASSO) around the proximal three major epicardial coronary vessels (LAD [left anterior descending artery], LCx [left circumflex artery], and RCA [right coronary artery]) were used to build logistic regression models. Finally, a FAI model, three radiomics models of PCAT (LAD, LCx, and RCA), and a combined model that used the scores of these independent models were constructed. The performance of the models was evaluated by identification, calibration, and clinical application. In training and validation cohorts, compared with the FAI model (AUC = 0.53, 0.50), the combined model achieved superior performance (AUC = 0.97, 0.95) while there was a significant difference of AUC between two models (p < 0.05). The calibration curves of the combined model demonstrated the smallest Brier score loss. Decision curve analysis suggested that the combined model provided higher clinical benefit than the FAI model. The CCTA-based radiomics phenotype of PCAT outperforms the FAI model in discriminating acute MI from UA. The combination of PCAT radiomics and FAI could further enhance the performance of acute MI identification. • Fat attenuation index based on CCTA can detect inflammation-induced changes in the ratio of lipid to aqueous phase in pericoronary adipose tissue. • Fat attenuation index cannot distinguish acute MI patients from UA patients, suggesting that the two groups have the same degree of ratio of lipid to aqueous phase in pericoronary adipose tissue. • Radiomics features of PCAT have the potential to distinguish acute MI patients from UA patients.

The Predictive Value of the Perivascular Adipose Tissue CT Fat Attenuation Index for Coronary In-stent Restenosis.

ObjectivesTo investigate the association between the perivascular adipose tissue (PVAT) fat attenuation index (FAI) derived from coronary computed tomography angiography (CCTA) and the prevalence of in-stent restenosis (ISR) in patients with coronary stent implantation.MethodsA total of 117 patients with previous coronary stenting referred for invasive coronary angiography (ICA) were enrolled in this retrospective observational analysis. All patients underwent CCTA between July 2016 and November 2021. The deep learning-based (DL-based) method was used to analyze and measure the peri-stent FAI value. Additionally, the relationship between hematological and biochemical parameters collected from all the patients was also explored. The least absolute shrinkage and selection operator (LASSO) method was applied to the most useful feature selection, and binary logistic regression was used to test the association between the selected features and ISR. The predictive performance for ISR of the identified subgroups was evaluated by calculating the area under the curve (AUC) of receiver operator curves plotted for each model. The Pearson correlation coefficient was used to assess the correlation of peri-stent FAI values with degrees of ISR.ResultsThe peri-stent FAI values in the ISR group were significantly higher than those in the non-ISR group (−78.1 ± 6.2 HU vs. −87.2 ± 7.3 HU, p < 0.001). The predictive ISR features based on the LASSO analysis were peri-stent FAI, high-density lipoprotein cholesterol (HDL-C), apolipoprotein A1 (ApoA1), and high-sensitivity c-reactive protein (hs-CRP), with an AUC of 0.849, 0.632, 0.620, and 0.569, respectively. Binary logistic regression analysis determined that peri-stent FAI was uniquely and independently associated with ISR after adjusting for other risk factors (odds ratio [OR] 1.403; 95% CI: 1.211 to 1.625; p < 0.001). In the subgroup analysis, the AUCs of the left anterior descending coronary artery (LAD), left circumflex coronary artery (LCx), and right coronary artery (RCA) stents groups were 0.80, 0.87, and 0.96, respectively. The Pearson's correlation coefficient indicated a term moderately correlation between ISR severity and peri-stent FAI values (r = 0.579, P < 0.001).ConclusionsThe peri-stent FAI can be used as an independently non-invasive biomarker to predict ISR risk and severity after stent implantation.

The Perivascular Fat Attenuation Index Improves the Diagnostic Performance for Functional Coronary Stenosis.

Background: Coronary computed tomography angiography (CCTA) is an established first-line test in the investigation of patients with suspected coronary artery disease (CAD), while the perivascular fat attenuation index (FAI) derived from CT seems to be a feasible and efficient tool for the identification of ischemia. The association between the FAI and lesion-specific ischemia as assessed by fractional flow reserve (FFR) remains unclear. Methods: In a total of 261 patients, 294 vessels were assessed for CCTA stenosis, vessel-specific FAI, lesion-specific FAI, and plaque characteristics. The diagnostic accuracies of each parameter and the combined approach were analyzed via the receiver operating characteristic curve (ROC) with FFR as the reference standard. The determinants of FAI were statistically analyzed. Results: The cutoff values of vessel-specific FAI and lesion-specific FAI scores calculated according to the Youden index were −70.97 and −73.95 HU, respectively. No significant differences were noted between them; however, they exhibited a strong correlation. No significant differences were noted between the area under the curve (AUC) scores of vessel-specific FAI (0.677), lesion-specific FAI (0.665), and CCTA (0.607) (p > 0.05 for all) results. The addition of two FAI measures to the CCTA showed improvements in the discrimination (AUC) and reclassification ability (relative integrated discrimination improvement (IDI) and category-free net reclassification index (NRI)), vessel-specific FAI (AUC, 0.696; NRI, 49.6%; IDI, 5.9%), and lesion-specific FAI scores (AUC, 0.676; NRI, 43.3%; IDI, 5.4%); (p < 0.01 for all). Multivariate analysis revealed that low-attenuation plaque (LAP) volume was an independent predictor of two FAI measures. Conclusion: The combined approach of adding vessel-specific FAI or lesion-specific FAI scores could improve the identification of ischemia compared with CCTA alone. The LAP volume was the independent risk factor for both tools.

Is Fatty Liver Associated with Increased Mortality and Morbidity in Coronavirus Disease 2019 (COVID-19) Pneumonia?

BackgroundFatty liver has been shown to be associated with severe COVID-19 disease without any impact on mortality. This is based on heterogenous criteria for defining both fatty liver as well as the severity parameters. This study aimed to study the impact of fatty liver on the mortality and severity of disease in patients with COVID-19 pneumonia.MethodsIn a case control study design, patients with COVID-19 pneumonia (COVID-19 computed tomography severity index [CTSI] on high-resolution computed tomography chest of ≥1) with fatty liver (defined as liver to spleen attenuation index ≤5 on noncontrast computed tomography cuts of upper abdomen) were compared with those without fatty liver. The primary outcome measure was in-hospital mortality, and the secondary outcome measures were CTSI score, need for intensive care unit (ICU) care, need for ventilatory support, duration of ICU stay, and duration of hospital stay.ResultsOf 446 patients with COVID-19 pneumonia, 289 (64.7%)admitted to Max Hospital, Saket, India, between January 1, 2021, and October 30, 2021, had fatty liver. Fifty-nine of 446 patients died during the index admission. In-hospital mortality was not different between patients with fatty liver (38 [13.24%]) or without fatty liver (21 [13.81%]). COVID-19 CTSI score was found to be significantly higher among patients who had fatty liver (13.40 [5.16] vs 11.81 [5.50]; P = 0.003). There was no difference in the requirement of ICU (94 [32%] vs 62 [39.49%]; P = 0.752), requirement of ventilatory support (27 [9.34%] vs 14 [8.91%]; P = 0.385), duration of ICU stay (8.29 [6.87] vs 7.07 [5.71] days; P = 0.208), and duration of hospital stay (10.10 [7.14] vs 10.69 [8.13] days; P = 0.430) between the groups with fatty liver or no fatty liver. Similarly, no difference was found in primary or secondary outcomes measure between the group with severe fatty liver vs mild/moderate or no fatty liver. High total leucocyte count and Fibrosis-4 (FIB-4) index were independently associated with mortality.ConclusionsFatty liver may not be associated with increased mortality or clinical morbidity in patients who have COVID-19 pneumonia.

A preliminary coronary computed tomography angiography-based study of perivascular fat attenuation index: relation with epicardial adipose tissue and its distribution over the entire coronary vasculature.

To investigate the perivascular fat attenuation index (FAI) in association with epicardial adipose tissue (EAT) parameters and its distribution over the entire coronary vasculature in patients with known or suspected coronary artery disease (CAD). Patients with known or suspected CAD who underwent coronary computed tomography angiography from January 1, 2019, to June 1, 2019, were retrospectively included. The perivascular FAI was quantified on four main epicardial coronary arteries and seven coronary segments. Moreover, EAT density and volume were measured. We included 192 consecutive patients (55 without coronary plaque [mean age 46.4 ± 13.2 years, 69.1% male] and 137 with coronary plaque [mean age 57.9 ± 13.0 years, 84.7% male]). EAT density was lower than perivascular FAI in both groups, but they exhibited substantial correlation (- 83.33 ± 4.54 vs. - 78.22 ± 6.52 HU, p < 0.001; r = 0.667 in plaque- patients and - 83.11 ± 4.48 vs. - 77.81 ± 5.63 HU, p < 0.001; r = 0.778 in plaque+ patients). The left main coronary artery had the highest perivascular FAI, followed by the left circumflex artery. The perivascular FAI in proximal segments was significantly higher compared to that in distal segments (all p < 0.05). Furthermore, the presence of plaque did not alter perivascular FAI on the patient or segmental level. The perivascular FAI was significantly higher than EAT density and correlated substantially with EAT density. The perivascular FAI distribution over the entire coronary tree varied and prompted for vessel-specific or segment-specific thresholds to determine abnormal perivascular FAI in practice. • The perivascular FAI correlated well with EAT density and had higher values than EAT density. • The distributions of perivascular FAI differ between coronary vessels or segments; considering segment and vessel confounding factors while conducting a perivascular FAI study is necessary. • No significant difference of perivascular FAI was observed between patients without and with coronary plaque, nor between coronary segments without plaque and those with plaque.

Bipolar disorder and bone health: A case-control study

BackgroundBipolar disorder (BD) is associated with significant psychological and physical comorbidity. Yet little is known about the bone health of individuals with BD. Thus, we aimed to investigate the association between BD and bone health in a population-based sample of women. MethodsWomen with a history of BD (cases; n = 117) were recruited from public and private health care settings and controls, without BD, were drawn from the Geelong Osteoporosis Study (n = 909). BD was identified using a semi-structured clinical interview (SCID-I/NP). Bone mineral density (BMD) was measured at the spine, femoral neck and total body using dual energy x-ray absorptiometry, and bone quality by quantitative heel ultrasound and included the following parameters: Speed of Sound (SOS), Broadband Ultrasound Attenuation (BUA) and Stiffness Index (SI). Weight and height were measured and information on medication use and lifestyle was obtained. ResultsAdjusted mean BMD among the cases was 4.3% lower at the hip and 1.6% lower at the total body compared to controls. Age was an effect modifier at the spine. Among women <50 years, mean spine BMD for cases was 3.5% lower than controls. No differences in spine BMD for those ≥50 years were detected. Cases also had a 1.0%, 3.2% and 7.8% lower adjusted mean SOS, BUA and SI compared to controls, respectively. LimitationsCourse, chronicity and recovery of BD were not explored in relation to bone health. ConclusionThese data suggest BD is associated with low bone quantity and quality in women. Replication and research into underlying mechanisms is warranted.

Toward Confocal Chromatic Sensing in Nuclear Reactors: In Situ Optical Refractive Index Measurements of Bulk Glass

To measure fuel rod swelling in a nuclear research reactor, our research has focused on the development of an optical confocal chromatic sensor, allowing contactless measurements of radial changes in fuel rods. This sensor must be able to operate in the harsh and hot environment of a reactor, especially under high neutron fluences up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{19}~{n}_{\mathrm{ fast}}/\text {cm}^{2}$ </tex-math></inline-formula> and gamma doses of a few GGy. When exposed to such radiation levels, the properties of bulk optical glasses are known to be affected by two main phenomena: radiation-induced attenuation (RIA) and radiation-induced refractive index change (RIRIC). With the objective of testing glasses as candidates for a future confocal chromatic sensor, we created a dedicated setup for the online monitoring of the glasses’ RIRIC in the core reactor with a measurement principle relying on interferometry. Since not only the refractive index (RI) but also the length of the samples changes under neutron radiation through compaction, we measured the variation of the optical path (OP) ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$nL$ </tex-math></inline-formula> ). To assess the performance of our setup, preliminary in-lab tests were performed to evaluate the feasibility of measuring the small RI changes caused by external temperature changes. Due to this study, we were able to obtain data that were not yet available in the literature regarding the temperature-induced RI variation of several bulk glasses, including radiation-hardened glasses, up to 350 °C. This information is crucial for the targeted application, as the confocal chromatic sensor will have to operate at such elevated temperatures.

18F-Fluorodeoksiglukoz positron emisyon tomografi/bilgisayarlı tomografi’de kahverengi yağ dokusu aktivitesi ve kanser durumunun korelasyonu

Aim: In this study, we aimed to compare brown adipose tissue (BAT) activity on 18F-Flourodeoxyglucose Positron Emission Tomography (PET)/Computed Tomography(CT) in patients with and without active cancer. &#x0D; Material and Methods: Results of the patients who underwent 18F-FDG PET/CT between January 2014 and February 2018 in Nuclear Medicine Department were evaluated retrospectively. Age, gender, body mass index (BMI), serum levels of glucose, bilirubin, total cholesterol (T-chol), low-density lipoprotein (LDL) and triglyceride (TG) of the patients were noted from the hospital database. Mean outdoor temperature of the day during PET/CT imaging was searched from National Weather Service archives. Diagnosis and disease activity status on PET/CT imaging were evaluated retrospectively. Standardized uptake value (SUV) and brown adipose tissue volume (BAV) were calculated on PET/CT images. Additionally, hepatic attenuation index and subcutaneous adipose tissue thickness (SCATT) were calculated from CT images. Difference between median SUV and BAV among groups with and without active cancer was analyzed. &#x0D; Results: Totally 78 (54 F; 24 M; mean age 34.415.6) patients who underwent 18F-FDG PET/CT for different oncological indications were included in the analysis. All the patients had different degrees of BAT uptake on PET/CT images. Median (min-max) values for SUV, BAV and SCATT were found as 8.0 (2.7-37.0), 26.9 (2.1- 116.0) cm3 and 15.0 (3.0- 46.0) mm, respectively. Hepatic attenuation index was 0-5%, 6-30% and &gt;30% in 56 (71%), 20 (26%) and 2 (3%) patients, respectively. Active disease was observed in 26 (33%) patients during PET/CT imaging. In the evaluation of the distribution of the adipose tissue parameters, median SUV (p=0.008) and BAV (p=0.008) of groups with and without active cancer were found statistically significant. &#x0D; Conclusion: BAT activity in patients with active cancer seems to be higher than that in patients without active disease, supporting the possible role of adipose tissue activation on cancer development and progression.

Identification of high-risk carotid plaque by using carotid perivascular fat density on computed tomography angiography

BackgroundPerivascular fat attenuation index is considered a sensitive biomarker of vulnerable coronary plaques. However, its application in studying the carotid artery are unknown. PurposeThis study aimed to explore the association between cerebrovascular symptoms and carotid attenuation density of perivascular adipose tissue (PVAT) on computed tomography angiography (CTA). MethodsA total of 206 participants (mean age, 63.9 ± 7.9 years, 145 men) who underwent CTA were retrospectively analyzed. Perivascular fat density (PFD) was evaluated via CTA. The association between PFD and the occurrence of cerebrovascular symptoms was examined via generalized estimating equations and receiver operating characteristic analysis. ResultsAmong the 206 subjects, 49.5% (plaques were observed in 102 patients) presented cerebrovascular symptoms. Plaques with symptoms (−55.0 ± 10.0 Hounsfield units [HU]) had a higher PFD than those without symptoms (−68.0 ± 10.3 HU) (p < 0.001). After adjusting for hyperlipidemia, statin use, antiplatelet use, calcification, degree of luminal stenosis, maximum plaque thickness, and ulceration, PFD was found to be strongly associated with cerebrovascular symptoms (OR, 1.13; 95% CI, 1.07–1.19; p < 0.001). Receiver operating characteristic analysis revealed an area under the curve of 0.81 by using PFD measurements to discriminate between symptomatic and asymptomatic plaques with a sensitivity of 87.3% and a specificity of 60.6%. ConclusionsAn increase in attenuation density of PVAT on CTA was found to be related to an increase in the risks of cerebrovascular symptoms. PFD might serve as an imaging marker of symptomatic carotid plaques.

Pericoronary fat attenuation index and coronary plaque quantified from coronary computed tomography angiography identify ischemia-causing lesions

BackgroundThe association between pericoronary fat attenuation index (FAI), plaque characteristics, and lesion-specific ischemia identified by fractional flow reserve (FFR) remains unclear. MethodsCoronary computed tomography angiography (CCTA) stenosis, FAI, plaque characteristics, FFR derived from computed tomography (FFRCT) and FFR were assessed in 280 vessels of 247 patients. Stenosis ≥50% was considered obstructive. Optimal thresholds of FAI and plaque variables were defined by the area under the receiver-operating characteristics curve (AUC) analysis. Ischemia was defined by FFR ≤ 0.80. ResultsFAI ≥ −71.9 HU, low-attenuation plaque (LAP) ≥ 49.62 mm3 and aggregate plaque volume (APV) ≥ 28.91% predicted ischemia independent of other plaque characteristics. The addition of FAI ≥ −71.9 HU improved discrimination (AUC, 0.720 vs. 0.674, P = 0.035) and reclassification abilities (category-free net reclassification index [NRI], 0.470, P < 0.001; relative integrated discrimination improvement [IDI], 0.047, P < 0.001) of ischemia compared with stenosis evaluation alone, with further discrimination (AUC, 0.772 vs. 0.720, P = 0.028) and reclassification abilities (NRI, 0.385, P = 0.001; relative IDI, 0.077, P < 0.001) of ischemia by adding information regarding LAP ≥49.62 mm3 + APV ≥ 28.91%. And the diagnostic performance of combination approach was comparable to that of FFRCT alone (AUC, 0.772 vs. 0.762, P = 0.771). ConclusionsStenosis severity, FAI, plaque characteristics predicted lesion-specific ischemia. The combination of FAI and plaque assessment improved the discrimination of ischemia compared with stenosis assessment alone.

H ∞ Consensus Design and Online Scheduling for Multiagent Systems with Switching Topologies via Deep Reinforcement Learning

This paper is devoted to H ∞ consensus design and online scheduling for homogeneous multiagent systems (MASs) with switching topologies via deep reinforcement learning. The model of homogeneous MASs with switching topologies is established based on switched systems theory, in which the switching of topologies is viewed as the switching among subsystems. By employing linear transformation, the closed-loop systems of MASs are converted into reduced-order systems. The problem of H ∞ consensus design can be transformed to the issue of H ∞ control. It is supposed that the consensus protocol is composed of two parts: dynamics-based protocol and learning-based protocol, where dynamics-based protocol is provided to guarantee the convergence and weighted attenuation and learning-based protocol is proposed to improve the transient performance. Then, the multiple Lyapunov function (MLF) method and mode-dependent average dwell time (MDADT) method are combined to ensure the stability and weighted H ∞ disturbance attenuation index of reduced-order systems. The sufficient existing conditions of dynamics-based protocol are given through the feasible solutions of linear matrix inequalities (LMIs). Moreover, the online scheduling is formulated as a Markov decision process, and the deep deterministic policy gradient (DDPG) algorithm in the framework of actor-critic is proposed for the compensation of disturbance to explore optimal control policy. The online scheduling of parameters of MASs is viewed as bounded compensation of dynamics-based protocol, whose stability can be guaranteed by nonfragile control theory. Finally, simulation results are provided to illustrate the effectiveness and superiority of the proposed method.

Epicardial Adipose Tissue Attenuation and Fat Attenuation Index: Phantom Study and In Vivo Measurements With Photon-Counting Detector CT.

BACKGROUND. Epicardial adipose tissue (EAT) attenuation is a vascular inflammation marker predictive of adverse cardiac events. The fat attenuation index (FAI) assesses fat attenuation for predefined coronary segments. Photon-counting detector (PCD) CT uses routine virtual monoenergetic image (VMI) reconstructions. VMI energy level may affect EAT attenuation and FAI measurements. OBJECTIVE. The purpose of this article was to assess EAT attenuation and FAI measurements at different monoenergetic energy levels in patients undergoing coronary CTA using a first-generation whole-body dual-source PCD CT scanner. METHODS. An anthropomorphic phantom at two sizes with a fat insert was imaged on a first-generation dual-source PCD CT scanner and, as a reference, on a conventional energy-integrating detector (EID) CT scanner at 120 kV. Thirty patients (11 women, 19 men; mean age, 48 ± 10 years; Agatston score < 60) who underwent an ECG-gated unenhanced calcium-scoring scan and contrast-enhanced coronary CTA by PCD CT were retrospectively evaluated. VMIs from 55 to 80 keV at 5-keV increments were reconstructed. EAT attenuation was manually measured on unenhanced and contrast-enhanced images. FAI was calculated using semiautomated software. RESULTS. The attenuation of the phantom fat insert was -69 HU for the reference EID CT; the closest attenuation for PCD CT was observed at 70 keV for the small (-69 HU) and large (-70 HU) phantoms. In patients, EAT attenuation increased for unenhanced acquisition from -111 ± 11 HU at 55 keV to -82 ± 9 HU at 80 keV and for contrast-enhanced acquisition from -104 ± 11 HU at 55 keV to -81 ± 9 HU at 80 keV. The mean attenuation difference between unenhanced and contrast-enhanced scans decreased with increasing energy level (from 7 ± 12 HU to 1 ± 10 HU). The FAI increased from -89 ± 8 HU at 55 keV to -77 ± 12 HU at 80 keV for the right coronary artery, -95 ± 11 HU at 55 keV to -85 ± 11 HU at 80 keV for the left anterior descending artery, and -87 ± 10 HU at 55 keV to -80 ± 12 HU at 80 keV for the circumflex artery. CONCLUSION. EAT attenuation and FAI measurements using PCD CT are impacted by VMI energy level and contrast enhancement. Use of VMI reconstruction at 70 keV provides fat attenuation approximating conventional polychromatic measurements. CLINICAL IMPACT. The findings may help standardize evaluation of pericoronary inflammation by PCD CT as a measure of patients' cardiac risk.

Small-for-Size versus Standard-Size Graft in Living Donor Liver Transplantation.

To compare the outcome of small-for-size grafts versus standard-size grafts regarding the frequency of postoperative complications, early graft dysfunction, and 1-year survival. Retrospective cohort study. Pir Abdul Qadir Shah Jeelani Institute of Medical Sciences (PAQSJIMS) Hospital, Gambat, Sindh, Pakistan from March 2019 to April 2020. A total of 147 living donor liver transplant recipients' data were retrospectively evaluated. Study participants were divided into two groups; small-for-size graft (GRWR <0.8%) and standard-size graft (GRWR >0.8%). Recipients' demographics, graft characteristics, operative parameters, postoperative complications, and graft survival were compared in both groups. Out of 147 recipients, 21 were found to have small-for-size graft, while 126 patients had the standard-size graft. Mean GRWR in small-for-size graft group was 0.73 + 0.4 (0.63-0.79), while 0.93 + 0.82 (0.81-3.0) in standard-size graft group. A statistically significant difference was found while comparing body mass index (p <0.001), hepatic venous reconstruction (p = 0.013), and liver attenuation index (p <0.001) between both study groups. While all other recipient and donor characteristics, demographical data, operative variables, postoperative lab, and complications were comparable in both groups (p >0.05). Kaplan-Meier analysis showed that 1-year survival rate for small-for-size graft recipients was 90.5%, while the survival rate for the standard-size graft was 96.0% (p = 0.272). Frequency of post-op complications was comparable in both groups. The graft survival in small-for-size grafts was as good as for standard-size grafts. Key Words: Living donor liver transplantation, GRWR, Small-for-size graft, Standard-size graft.

Coronary Computed Tomography Angiographic Predictors of Non-culprit Territory Unrecognized Myocardial Infarction Assessed by Cardiac Magnetic Resonance in Non-ST-elevation Acute Coronary Syndrome.

ObjectivesThis study sought to assess the predictors of coronary computed tomography angiographic findings for non-infarct-related (non-IR) territory unrecognized myocardial infarction (UMI) in patients with a first episode of non-ST-elevation acute coronary syndrome (NSTE-ACS).BackgroundUMI detected by cardiac magnetic resonance imaging (CMR) is associated with adverse outcomes in patients with both acute coronary syndrome and chronic coronary syndrome. However, the association between the presence of UMI and coronary computed tomography angiographic (CCTA) findings remains unknown.MethodsWe investigated 158 patients with a first clinical episode of NSTE-ACS, who underwent pre-PCI 320-slice CCTA and uncomplicated urgent percutaneous coronary intervention (PCI) within 48 h of admission. In these patients, post-PCI CMR was performed within 30 days from urgent PCI and before non-IR lesion staged PCI. UMI was assessed using late gadolinium enhancement (LGE)-CMR by identifying regions of hyperenhancement with an ischemic distribution pattern in non-IR territories (non-IR UMI). CCTA analysis included qualitative and quantitative assessments of the culprit segment, Agatston score, mean peri-coronary fat attenuation index (FAI), epicardial fat volume (EFV) and epicardial fat attenuation (EFA).ResultsNon-IR UMI was detected in 30 vessel territories (9.7%, 30/308 vessels) of 28 patients (17.7%, 28/158 patients). The presence of low-attenuation plaque, spotty calcification, napkin ring sign, and positive remodeling was not significantly different between vessels with and without subtended non-IR UMI. Agatston score >30.0 (OR: 8.39, 95% confidence interval (CI): 2.17 to 32.45, p = 0.002), mean FAI >-64.3 (OR: 3.23, 95% CI: 1.34 to 7.81, p = 0.009), and stenosis severity (OR: 1.04, 95% CI: 1.02 to 1.06, p < 0.001) were independently associated with non-IR UMI. Neither EFV (p = 0.340) nor EFA (p = 0.700) was associated with non-IR UMI.ConclusionThe prevalence of non-IR UMI was 17.7 % in patients with first NSTE-ACS presentation. Agatston score, mean FAI, and coronary stenosis severity were independent CCTA predictors of the presence of non-IR UMI. The integrated CCTA assessment may help identify the presence of non-IR UMI before urgent PCI.

Changes of serum uric acid levels in patients with chronic hepatitis C after using direct antiviral agents therapy

Objective: To observe the changes of serum uric acid levels and clinical characteristic in patients with chronic hepatitis C combined with hyperuricemia after direct antiviral agents (DAA) therapy. Methods: A prospective cohort study was used to investigate the risk of hyperuricemia in patients with chronic hepatitis C who received DAA treatment to obtain sustained virological response. The changes and factors influencing serum uric acid levels after 12 weeks of DAA treatment were observed. Comparisons between groups were performed using χ (2) test or Fisher's exact test, analysis of variance, Student's t test, or the non-parametric Mann-Whitney U test. Serum uric acid (SUA) changes, liver and kidney function indexes before and after treatment were compared by repeated measurement and paired t-test. Uric acid reduction was defined as a decrease in SUA from baseline at 12 weeks after treatment. Rates of change in eGFR, aspartate aminotransferase/platelet ratio, alanine aminotransferase and controlled attenuation parameter were defined from baseline (baseline to 12 weeks after treatment). Binary logistic regression analysis was used to compare the risk factors and factors influencing high and low uric acid level. Results: 161 cases with chronic hepatitis C who received DAA treatment were included, of which 19.3% patients were hyperuricemic. eGFR < 60 ml/(min·1.73 m(2)) and body mass index were independent risk factors for hyperuricemia in patients with chronic hepatitis C (eGFR: OR = 0.123, P = 0.002; body mass index: OR = 1.220, P = 0.002). SUA levels was changed significantly before treatment, at the end of treatment and at 12 weeks after treatment (327.96 vs. 320.76 vs. 314.92, F = 3.272, P = 0.042). At 12 weeks after treatment, SUA, liver stiffness, alanine aminotransferase and control attenuation parameters were all significantly lower than baseline (P < 0.05). The rate of increase in eGFR from baseline and the rate of decrease in controlled attenuation parameter during treatment were the factors influencing SUA reduction (eGFR: OR = 5124, P = 0.000; controlled attenuation index: OR = 0.010, P = 0.039). Conclusion: In chronic hepatitis C, reduced eGFR and body mass index are the risk factors for the development of hyperuricemia and a significant reduction in serum uric acid levels after DAA treatment can eradicate the virus.

Long-term prognostic value of the serial changes of CT-derived fractional flow reserve and perivascular fat attenuation index.

To investigate the serial changes of computed tomography (CT) fractional flow reserve (CT-FFR) and fat attenuation index (FAI), and explore their relationships with long-term clinical outcomes. Consecutive symptomatic patients with an intermediate pretest probability of coronary artery disease 1-4 were prospectively enrolled if coronary CT angiography (CCTA) revealed at least 1 lesion with 30-70% stenosis on major epicardial arteries. Follow-up CCTA was performed at 1 to 1.5-year intervals. All patients were further followed up after the second CCTA until September 2019. The Coronary Artery Disease - Reporting and Data System (CAD-RADS) grade, high-risk plaque features, lesion-specific CT-FFR, and FAI were measured for prognosis analysis. A total of 263 patients were included in the analysis, and 38 major adverse cardiac events (MACEs) occurred. In the MACE group, the lesion-specific CT-FFR decreased significantly at the follow-up CCTA [0.80 (0.74-0.90) versus 0.85 (0.76-0.93); P=0.01], whereas the FAI did not notably increase (-70.4±8.9 versus -71.3±7.1 HU; P=0.436). In the non-MACE group, lesion-specific CT-FFR increased markedly [0.91 (0.84-0.95) versus 0.90 (0.82-0.94); P<0.001], while the FAI decreased substantially (-74.0±10.8 versus -72.4±11.5 HU; P=0.004). Decreased CT-FFR (adjusted overall hazard ratio =2.455; P=0.023) and increased FAI (adjusted hazard ratio =2.956; P=0.002) were the strongest independent predictors of MACEs. Serial changes of CT-FFR and FAI provided incremental prognostic value (Concordance statistic =0.716; P=0.003; over conventional clinical and imaging parameters (Concordance statistic =0.762; P=0.004). Decreased CT-FFR and increased FAI at follow-up CCTA were the 2 strongest predictors of MACEs. Serial changes of CT-FFR and FAI provided incremental prognostic value over conventional clinical and imaging parameters for risk stratification. In addition, decreased CT-FFR provided incremental predictive value for MACEs from 15 months after second CCTA, while increased FAI added prognostic value from the second CCTA onwards.

Lipoprotein(a) is associated with coronary atheroma progression: analysis from a serial coronary computed tomography angiography study.

BACKGROUNDLipoprotein(a) [Lp(a)] has been closely related to coronary atherosclerosis and might affect perivascular inflammation due to its proinflammatory properties. However, there are limited data about Lp(a) and related perivascular inflammation on coronary atheroma progression. Therefore, this study aimed to investigate the associations between Lp(a) and the perivascular fat attenuation index (FAI) with coronary atheroma progression detected by coronary computed tomography angiography (CCTA).METHODSPatients who underwent serial CCTA examinations without a history of revascularization and with available data for Lp(a) within one month before or after baseline and follow-up CCTA imaging scans were considered to be included. CCTA quantitative analyses were performed to obtain the total plaque volume (TPV) and the perivascular FAI. Coronary plaque progression (PP) was defined as a ≥ 10% increase in the change of the TPV at the patient level or the presence of new-onset coronary atheroma lesions. The associations between Lp(a) or the perivascular FAI with PP were examined by multivariate logistic regression.RESULTSA total of 116 patients were ultimately enrolled in the present study with a mean CCTA interscan interval of 30.80 ± 13.50 months. Among the 116 patients (mean age: 53.49 ± 10.21 years, males: 83.6%), 32 patients presented PP during the follow-up interval. Lp(a) levels were significantly higher among PP patients than those among non-PP patients at both baseline [15.80 (9.09−33.60) mg/dLvs. 10.50 (4.75−19.71) mg/dL,P = 0.029] and follow-up [20.60 (10.45−34.55) mg/dLvs. 8.77 (5.00−18.78) mg/dL,P = 0.004]. However, there were no differences in the perivascular FAI between PP group and non-PP group at either baseline or follow-up. Multivariate logistic regression analysis showed that elevated baseline Lp(a) level (OR = 1.031, 95% CI: 1.005−1.058,P = 0.019) was an independent risk factor for PP after adjustment for other conventional variables. CONCLUSIONSLp(a) was independently associated with coronary atheroma progression beyond low-density lipoprotein cholesterol and other conventional risk factors. Further studies are warranted to identify the inflammation effect exhibited as the perivascular FAI on coronary atheroma progression.