The Influence of Aortic Wall Elasticity on the False Lumen in Aortic Dissection: An In Vitro Study

Cardiovascular Aspects of Radiolog

Associations between left ventricular function, vascular function and measures of cerebral small vessel disease: a cross-sectional magnetic resonance imaging study of the UK Biobank

Cardiolog

The impact of visceral and general obesity on vascular and left ventricutar function and geometry: a cross-sectional magnetic resonance imaging study of the UK Biobank

Aims We aimed to evaluate the associations of body fat distribution with cardiovascular function and geometry in the middle-aged general population.Methods and results Four thousand five hundred and ninety participants of the UK Biobank (54% female, mean age 61.1 +/- 7.2 years) underwent cardiac magnetic resonance for assessment of left ventricular (LV) parameters [end-diastolic volume (EDV), ejection fraction (EF), cardiac output (CO), and index (CI)] and magnetic resonance imaging for body composition analysis [subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT)]. Body fat percentage (BF%) was assessed by bioetectrical impedance. Linear regressions were performed to assess the impact of visceral (VAT) and general (SAT and BF%) obesity on cardiac function and geometry. Visceral obesity was associated with a smaller EDV [VAT: beta -1.74 (-1.15 to -2.33)1, lower EF NAT: beta -0.24 (-0.12 to -0.35), SAT: beta 0.02 (-0.04 to 0.08), and BF%: beta 0.02 (-0.02 to 0.06)] and the strongest negative association with CI [VAT: beta -0.05 (-0.06 to -0.04), SAT: beta -0.02 (-0.03 to -0.01), and BF% beta -0.01 (-0.013 to -0.007)]. In contrast, general obesity was associated with a larger EDV [SAT: beta 1.01 (0.72-1.30), BF%: beta 0.37 (0.23-0.51)] and a higher CO [SAT: beta 0.06 (0.05-0.07), BF%: beta 0.02 (0.01-0.03)]. In the gender-specific analysis, only men had a significant association between VAT and EF [beta -0.35 (-0.19 to -0.51)].Conclusions Visceral obesity was associated with a smaller LV EDV and subclinical lower LV systolic function in men, suggesting that visceral obesity might play a more important role compared to general obesity in LV remodelling.Cardiolog

Assessment of turbulent blood flow and wall shear stress in aortic coarctation using image-based simulations

In this study, we analyzed turbulent flows through a phantom (a 180 degrees bend with narrowing) at peak systole and a patient-specific coarctation of the aorta (CoA), with a pulsating flow, using magnetic resonance imaging (MRI) and computational fluid dynamics (CFD). For MRI, a 4D-flow MRI is performed using a 3T scanner. For CFD, the standard k - epsilon, shear stress transport k - omega, and Reynolds stress (RSM) models are applied. A good agreement between measured and simulated velocity is obtained for the phantom, especially for CFD with RSM. The wall shear stress (WSS) shows significant differences between CFD and MRI in absolute values, due to the limited near-wall resolution of MRI. However, normalized WSS shows qualitatively very similar distributions of the local values between MRI and CFD. Finally, a direct comparison between in vivo 4D-flow MRI and CFD with the RSM turbulence model is performed in the CoA. MRI can properly identify regions with locally elevated or suppressed WSS. If the exact values of the WSS are necessary, CFD is the preferred method. For future applications, we recommend the use of the combined MRI/CFD method for analysis and evaluation of the local flow patterns and WSS in the aorta.Cardiovascular Aspects of Radiolog

Scan-rescan reproducibility of segmental aortic wall shear stress as assessed by phase-specific segmentation with 4D flow MRI in healthy volunteers

Cardiovascular Aspects of Radiolog

Determining the optimal interval for imaging surveillance of ascending aortic aneurysms

Background Cardiovascular guidelines recommend (bi-)annual computed tomography (CT) or magnetic resonance imaging (MRI) for surveillance of the diameter of thoracic aortic aneurysms (TAAs). However, no previous study has demonstrated the necessity for this approach. The current study aims to provide patient-specific intervals for imaging follow-up of non-syndromic TAAs. Methods A total of 332 patients with non-syndromic ascending aortic aneurysms were followed over a median period of 6.7 years. Diameters were assessed using all available imaging techniques (echocardiography, CT and MRI). Growth rates were calculated from the differences between the first and last examinations. The diagnostic accuracy of follow-up protocols was calculated as the percentage of subjects requiring pre-emptive surgery in whom timely identification would have occurred. Results The mean growth rate in our population was 0.2 +/- 0.4 mm/year. The highest recorded growth rate was 2.0 mm/year, while 40.6% of patients showed no diameter expansion during follow-up. Females exhibited significantly higher growth rates than men (0.3 +/- 0.5 vs 0.2 +/- 0.4 mm/year, p = 0.007). Conversely, a bicuspid aortic valve was not associated with more rapid aortic growth. The optimal imaging protocol comprises triennial imaging of aneurysms 40-49 mm in diameter and yearly imaging of those measuring 50-54 mm. This strategy is as accurate as annual follow-up, but reduces the number of imaging examinations by 29.9%. Conclusions In our population of patients with non-syndromic TAAs, we found aneurysm growth rates to be lower than those previously reported. Yearly imaging does not lead to changes in the management of small aneurysms. Thus, lower imaging frequencies might be a good alternative approach.Cardiovascular Aspects of Radiolog

Intracardiac 4D flow MRI in congenital heart disease : recommendations on behalf of the ISMRM flow & motion study group

Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019.Cardiovascular Aspects of Radiolog