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Purpose: To explore the potential differences in epicardial adipose tissue (EAT) volume and attenuation measurements between photon-counting detector (PCD) and energy-integrating detector (EID)-CT systems., Methods: Fifty patients (mean age 69 ± 8 years, 41 male [82 %]) were prospectively enrolled for a research coronary CT angiography (CCTA) on a PCD-CT within 30 days after clinical EID-based CCTA. EID-CT acquisitions were reconstructed using a Bv40 kernel at 0.6 mm slice thickness. The PCD-CT acquisition was reconstructed at a down-sampled resolution (0.6 mm, Bv40; [PCD-DS]) and at ultra-high resolutions (PCD-UHR) with a 0.2 mm slice thickness and Bv40, Bv48, and Bv64 kernels. EAT segmentation was performed semi-automatically at about 1 cm intervals and interpolated to cover the whole epicardium within a threshold of -190 to -30 HU. A subgroup analysis was performed based on quartile groups created from EID-CT data and PCD-UHR Bv48 data. Differences were measured using repeated-measures ANOVA and the Friedman test. Correlations were tested using Pearson's and Spearman's rho, and agreement using Bland-Altman plots., Results: EAT volumes significantly differed between some reconstructions (e.g., Eid-Ct: 138 ml [IQR 100, 188]; PCD-DS: 147 ml [110, 206]; P<0.001). Overall, correlations between PCD-UHR and EID-CT EAT volumes were excellent, e.g. PCD-UHR Bv48 : r: 0.976 (95 % CI: 0.958, 0.987); P<0.001; with good agreement (mean bias: -9.5 ml; limits of agreement [LoA]: -40.6, 21.6). On the other hand, correlations regarding EAT attenuation was moderate, e.g. PCD-UHR BV48 : r: 0.655 (95 % CI: 0.461, 0.790); P<0.001; mean bias: 6.5 HU; LoA: -2.0, 15.0., Conclusion: EAT attenuation and volume measurements demonstrated different absolute values between PCD-UHR, PCD-DS as well as EID-CT reconstructions, but showed similar tendencies on an intra-individual level. New protocols and threshold ranges need to be developed to allow comparison between PCD-CT and EID-CT data., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: UJS receives institutional research support and / or personal fees from Bayer, Bracco, Elucid Bioimaging, Guerbet, HeartFlow, Keya Medical, and Siemens. AVS receives institutional research support and / or personal fees from Elucid Bioimaging and Siemens. TE received a speaker fee and travel support from Siemens, institutional research support by Siemens and is a consultant at Circle CVI. JOD is an employee of Siemens., (Copyright © 2024. Published by Elsevier B.V.)

This retrospective study investigates perivascular adipose tissue (PVAT) alterations in CT as a marker of inflammation in patients with abdominal aortic aneurysms (AAA). 100 abdominal CT scans of patients with abdominal aortic aneurysms and 100 age and sex matched controls without underlying aortic disease were included. Artificial Intelligence (AI) assisted segmentation of the aorta and the surrounding adipose tissue was performed. Adipose tissue density was measured in Hounsfield units (HU) close (2-5mm, HU close ) and distant (10-12mm, HU distant ) to the aortic wall. To investigate alterations in adipose tissue density close to the aorta (HU close ) as a potential marker of inflammation, we calculated the difference HU Δ  = HU close -HU distant and the fat attenuation ratio HU ratio  = HU close /HU distant as normalized attenuation measures. These two markers were compared i) inter-individually between AAA patients and controls and ii) intra-individually between the aneurysmal and non-aneurysmal segments in AAA patients. Since most AAAs are generally observed infrarenal, the aneurysmal section of the AAA patients was compared with the infrarenal section of the aorta of the control patients. In inter-individual comparisons, higher HU Δ and a lower HU ratio were observed (aneurysmal: 8.9 ± 5.1 HU vs. control: 6.9 ± 4.8 HU, p-value = 0.006; aneurysmal: 89.8 ± 5.7% vs. control: 92.1 ± 5.5% p-value = 0.004). In intra-individual comparisons, higher HU Δ and lower HU ratio were observed (aneurysmal: 8.9 ± 5.1 HU vs. non-aneurysmal: 5.5 ± 4.1 HU, p-value < 0.001; aneurysmal: 89.8 ± 5.7% vs. non-aneurysmal 93.3 ± 4.9%, p-value < 0.001). The results indicate PVAT density alterations in AAA patients. This motivates further research to establish non-invasive imaging markers for vascular and perivascular inflammation in AAA., (© 2024. The Author(s).)

Purpose: Inflammatory changes in epicardial (EAT) and pericardial adipose tissue (PAT) are associated with increased overall cardiovascular risk. Using routine, preinterventional cardiac CT data, we examined the predictive value of quantity and quality of EAT and PAT for outcome after transcatheter aortic valve replacement (TAVR)., Materials and Methods: Cardiac CT data of 1197 patients who underwent TAVR at the in-house heart center between 2011 and 2020 were retrospectively analyzed. The amount and density of EAT and PAT were quantified from single-slice CT images at the level of the aortic valve. Using established risk scores and known independent risk factors, a clinical benchmark model (BMI, Chronic kidney disease stage, EuroSCORE 2, STS Prom, year of intervention) for outcome prediction (2-year mortality) after TAVR was established. Subsequently, we tested whether the additional inclusion of area and density values of EAT and PAT in the clinical benchmark model improved prediction. For this purpose, the cohort was divided into a training (n=798) and a test cohort (n=399)., Results: Within the 2-year follow-up, 264 patients died. In the training cohort, particularly the addition of EAT density to the clinical benchmark model showed a significant association with outcome (hazard ratio 1.04, 95% CI: 1.01-1.07; P =0.013). In the test cohort, the outcome prediction of the clinical benchmark model was also significantly improved with the inclusion of EAT density (c-statistic: 0.589 vs. 0.628; P =0.026)., Conclusions: EAT density as a surrogate marker of EAT inflammation was associated with 2-year mortality after TAVR and may improve outcome prediction independent of established risk parameters., Competing Interests: The authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Impaired skeletal muscle quality is a major risk factor for adverse outcomes in acute respiratory failure. However, conventional methods for skeletal muscle assessment are inapplicable in the critical care setting. This study aimed to determine the prognostic value of computed tomography (CT) fatty muscle fraction (FMF) as a biomarker of muscle quality in patients undergoing extracorporeal membrane oxygenation (ECMO). To calculate FMF, paraspinal skeletal muscle area was obtained from clinical CT and separated into areas of fatty and lean muscle based on densitometric thresholds. The cohort was binarized according to median FMF. Patients with high FMF displayed significantly increased 1-year mortality (72.7% versus 55.8%, P = 0.036) on Kaplan-Meier analysis. A multivariable logistic regression model was built to test the impact of FMF on outcome. FMF was identified as a significant predictor of 1-year mortality (hazard ratio per percent FMF, 1.017 [95% confidence interval, 1.002-1.033]; P = 0.031), independent of anthropometric characteristics, Charlson Comorbidity Index, Simplified Acute Physiology Score, Respiratory Extracorporeal Membrane Oxygenation Survival Prediction Score, and duration of ECMO support. To conclude, FMF predicted 1-year mortality independently of established clinical prognosticators in ECMO patients and may have the potential to become a new muscle quality imaging biomarker, which is available from clinical CT.

Purpose: This cardiac magnetic resonance study was performed to assess myocardial fibrosis by evaluating T1-relaxation time (T1), to measure left ventricular (LV) strain, and to determine epicardial fat volume (EFV) in hypertensive patients with no history of cardiovascular (CV) events and to relate the results to the presence of coronary atherosclerotic artery disease (CAD) in these patients., Materials and Methods: A total of 123 subjects were examined at 1.5 T. Of them, 98 were hypertensive patients (58 men; mean age, 62.9±10.7 y; body mass index, 29.0±5.6 kg/m) and 25 were controls without CV risk factors or disease (13 men; 60.1±10.7 y; 28.1±5.4 kg/m). All patients had a well-treated blood pressure. In the hypertensive group, 56 patients had no CAD, whereas 42 patients had CAD. T1 was assessed by a modified Look-Locker inversion recovery sequence. Longitudinal and circumferential peak systolic strain (LS; CS) was determined with dedicated cardiac magnetic resonance software (feature tracking). EFV (normalized to the body surface area) was assessed by a 3D Dixon sequence., Results: T1 (ms) and EFV (mL/m) were higher and CS and LS (%) were lower in hypertensive patients compared with those in nonhypertensive controls (P<0.05), independent of the presence of CAD (controls: T1=967.2±16.9, LS=-25.2±4.6, CS=-28.7±5.0, EFV=58.2±21.1; hypertensive patients overall: T1=991.3±45.5, LS=-21.0±4.5, CS=-25.0±5.9, EFV=71.1±25.3; hypertensive patients without CAD: T1=991.6±48.4, LS=-21.0±4.7, CS=-24.6±6.3, EFV=71.3±26.6; hypertensive patients with CAD: T1=986.7±39.2, LS=-21.1±4.3, CS=-25.5±5.4, EFV=70.9±23.6). There were no significant differences between hypertensive patients with and those without CAD and between patients grouped according to the number of vessels affected (0-vessel disease, 1-vessel disease, 2-vessel disease, or 3-vessel disease)., Conclusions: Hypertension is associated with signs of myocardial fibrosis and an impaired LV contractility despite a normal LV ejection fraction, as well as with an increased EFV. However, CAD, in the absence of previous pathologies with consecutive myocardial ischemic damage, did not additionally affect these parameters.

Purpose: To determine epicardial fat volume (EFV) and aortic stiffness (assessed by aortic pulse wave velocity (PWV)) in healthy individuals, and to investigate the relationship of these parameters, and their association with body mass index (BMI) and age., Materials and Methods: 58 subjects (29 men, mean age 44.7 ± 13.9 years[y]) underwent a CMR exam at 1.5 Tesla. A 2 D velocity-encoded CMR scan was acquired to determine PWV. The EFV was measured based on a 3 D-mDixon sequence. Group comparisons were made between younger (age < 45y; n = 30; mean age 33.4 ± 6.6y) and older (> 45y; n = 28; 56.7 ± 8.4y) subjects and between subjects with a BMI < 25 kg/m(2) (n = 28; BMI 21.9 ± 2.5 kg/m(2)) and a BMI > 25 kg/m(2) (n = 30; 28.7 ± 4.0 kg/m(2)). Associations between the determined parameters were assessed by analyses of covariance (ANCOVAs)., Results: The mean values of PWV and EFV (normalized to body surface area) were 6.9 ± 1.9 m/s and 44.2 ± 25.0 ml/m(2), respectively. The PWV and EFV were significantly higher in the older group (PWV = 7.9 ± 2.0 m/s vs. 6.0 ± 1.2 m/s; EFV = 54.7 ml/m² vs. 34.5 ml/m²; p < 0.01, each), with no significant differences in BMI or sex. In the overweighted group the EFV was significantly higher than in subjects with a BMI < 25 kg/m² (EFV = 56.1 ± 27.1 ml/m(2) vs. 31.5 ± 14.6 ml/m(2); p < 0.01) but without a significant difference in PWV. ANCOVA revealed a significant correlation between EFV and PWV, also after adjustment for age (p = 0.025)., Conclusion: An association was found between age and EFV as well as PWV. EFV and PWV were related to each other also after adjustment for age. The metabolic and pro-inflammatory activity found with increased epicardial fat volume may promote the development of atherosclerosis and aortic stiffness. CMR may be valuable for future studies investigating the relationship between EFV and PWV in patients with increased cardiovascular risk., Key Points: • EFV and PWV can be assessed in a single CMR exam.• EFV and aortic stiffness are both associated with cardiovascular risk.• EFV correlates with aortic stiffness, possibly due to similar pro-inflammatory mechanisms. Citation Format: • Homsi R, Thomas D, Gieseke J et al. Epicardial Fat Volume and Aortic Stiffness in Healthy Individuals: A Quantitative Cardiac Magnetic Resonance Study. Fortschr Röntgenstr 2016; 188: 853 - 858., (© Georg Thieme Verlag KG Stuttgart · New York.)

Purpose: Using a three-dimensional ECG- and respiratory navigator gated magnetization prepared mDixon-sequence (3D-Dixon) we quantified epi- and pericardial fat volumes (EFV, PFV) in hypertensive men compared to a healthy control group and related the amount of fat volumes in hypertensive men to the presence of coronary artery disease (CAD) and myocardial infarction (MI)., Materials and Methods: 55 hypertensive men (mean age 63.02±10.73years [y]) with MI (n=22; mean age 61.55±10.50y) and without MI (n=33; mean age 63.17±10.93y), and a group of ten healthy men (mean age 59.00±8.41y) underwent a comprehensive cardiomagnetic resonance (CMR) examination on a 1.5T MR system (Ingenia, Philips). Hypertensive men without MI consisted of patients with CAD (n=15) and without CAD (n=18). EFV and PFV were assessed using 3D-Dixon. Fat only images were reconstructed online at the scanner, and the segmentation of fat volumes was performed based on fat fraction maps. EFV and PFV were normalized to the body surface area (ml/m(2))., Results: Mean EFV and PFV in all hypertensive men (81.8±33.90 and 194.86±83.51) as well as in hypertensive men with no CAD (74.53±26.40 and 174.60±65.70) were significantly higher than in the healthy controls (52.98±19.81 and 115.50±53.57; P<0.05, each). EFV and PFV in hypertensive men with MI (94.14±43.16 and 224.26±100.79) were significantly higher than in hypertensive men with no MI (73.57±23.27 and 175.26±63.07; P<0.05, each). There were no significant differences in age, BMI or heart rate between the groups., Conclusion: 3D-Dixon measurements revealed significantly higher epi- and pericardial fat volumes in hypertensive men with myocardial infarction compared to hypertensive men without MI. This finding underscores the role of cardiac fatty tissue as a proinflammatory and metabolically active organ. Non-invasive CMR-based whole volume measurement of epi- and pericardial fat may play a relevant future role in cardiovascular risk stratification and disease management., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)