scholarly journals Aortic stenosis reexpanded – a novel approach to determine aortic valve area with phase contrast cardiovascular magnetic resonance imaging

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
F Troger ◽  
I Lechner ◽  
M Reindl ◽  
C Tiller ◽  
M Holzknecht ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Cardiovascular Magnetic Resonance ◽  
Cardiovascular Magnetic Resonance Imaging ◽  
Phase Contrast ◽  
Aortic Valve Area ◽  
Resonance Imaging ◽  
Novel Approach ◽  
Cine Cmr ◽  
Valve Area

Abstract Background Transthoracic echocardiography (TTE) has become the diagnostic standard for evaluating aortic stenosis (AS) severity, mainly because of its advantages in comparison to the gold standard of cardiac catheterization. However, its inaccuracies in determining stroke volume (SV) and consequentially computing aortic valve area (AVA) call for a more precise and dependable method. Phase contrast cardiovascular magnetic resonance imaging (PC-CMR) is an aspiring tool to push these boundaries. Purpose The aim of this study was to validate a novel and simple approach based on PC-CMR against the invasive and echocardiographic determination of SV and AVA in patients with moderate and severe AS. Methods A total of 50 patients with moderate or severe AS underwent TTE, cardiac catheterization and CMR; AVA by PC-CMR was determined via plotting momentary flow across the valve against momentary flow velocity. SV via CMR was measured directly via PC-CMR and volumetrically using cine images. Invasive SV and AVA were determined via Fick principle and Gorlin formula, respectively. TTE yielded SV and AVA using the continuity equation. Finally, gradients were calculated via the modified Bernoulli equation. Results SV by PC-CMR showed a strong correlation with cine-CMR with no significant bias (r: 0.730, p<0.001; SV by PC-CMR: 85±31ml; SV by cine-CMR: 85±19ml, p=0.829). Peak gradients determined by PC-CMR were 65±29mmHg and correlated inversely with AVA by PC-CMR (r: −0.371; p=0.008). Mean AVA during the whole systolic phase showed a moderate correlation (r: 0.544, p<0.001) to invasive AVA with a small bias (AVA by CMR: 0.78±0.25cm2 versus invasive AVA: 0.70±0.23cm2, bias: 0.08cm2, p=0.017). Inter-methodical correlation and bias of AVA as measured by TTE and invasive AVA (AVA by TTE: 0.81±0.23cm2, r: 0.580, p<0.001, bias 0.11cm2, p<0.001) were similar to AVA by PC-CMR and invasive AVA. Conclusion PC-CMR provides a great option to yield reliable and solid SV values in patients with moderate and severe AS. Furthermore, continuous determination of flow volumes and flow velocities is able to determine AVA in these patients in an easy and reproducible manner. Our novel approach shines a light on the diagnostic potential of PC-CMR for non-invasive AS grading, especially in cases where echocardiography reaches its limits and where clinical findings appear inconclusive. FUNDunding Acknowledgement Type of funding sources: None. Central Illustration Cine (l,r) and PC-CMR (m) images in AS

scholarly journals A novel approach to determine aortic valve area with phase-contrast cardiovascular magnetic resonance

2022 ◽  
Vol 24 (1) ◽  
Author(s):  
Felix Troger ◽  
Ivan Lechner ◽  
Martin Reindl ◽  
Christina Tiller ◽  
Magdalena Holzknecht ◽  
...  
Keyword(s):  
Cardiovascular Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aortic Valve ◽  
Phase Contrast ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Aortic Valve Area ◽  
Novel Approach ◽  
Valve Area

Abstract Background Transthoracic echocardiography (TTE) is the diagnostic routine standard for assessing aortic stenosis (AS). However, its inaccuracies in determining stroke volume (SV) and aortic valve area (AVA) call for a more precise and dependable method. Phase-contrast cardiovascular magnetic resonance imaging (PC-CMR) is a promising tool to push these boundaries. Thus, the aim of this study was to validate a novel approach based on PC-CMR against the gold-standard of invasive determination of AVA in AS compared to TTE. Methods A total of 50 patients with moderate or severe AS underwent TTE, cardiac catheterization and CMR. AVA via PC-CMR was determined by plotting momentary flow across the valve against flow-velocity. SV by CMR was measured directly via PC-CMR and volumetrically using cine-images. Invasive SV and AVA were determined via Fick-principle and Gorlin-formula, respectively. TTE yielded SV and AVA using continuity equation. Gradients were calculated via the modified Bernoulli-equation. Results SV by PC-CMR (85 ± 31 ml) correlated strongly (r: 0.73, p < 0.001) with cine-CMR (85 ± 19 ml) without significant bias (lower and upper limits of agreement (LLoA and ULoA): − 41 ml and 44 ml, p = 0.83). In PC-CMR, mean pressure gradient correlated significantly with invasive determination (r: 0.36, p = 0.011). Mean AVA, as determined by PC-CMR during systole (0.78 ± 0.25 cm2), correlated moderately (r: 0.54, p < 0.001) with invasive AVA (0.70 ± 0.23 cm2), resulting in a small bias of 0.08 cm2 (LLoA and ULoA: − 0.36 cm2 and 0.55 cm2, p = 0.017). Inter-methodically, AVA by TTE (0.81 ± 0.23 cm2) compared to invasive determination showed similar correlations (r: 0.58, p < 0.001 with a bias of 0.11 cm2, LLoA and ULoA: − 0.30 and 0.52, p < 0.001) to PC-CMR. Intra- and interobserver reproducibility were excellent for AVA (intraclass-correlation-coefficients of 0.939 and 0.827, respectively). Conclusions Our novel approach using continuous determination of flow-volumes and velocities with PC-CMR enables simple AVA measurement with no bias to invasive assessment. This approach highlights non-invasive AS grading through CMR, especially when TTE findings are inconclusive.

scholarly journals Phase-contrast magnetic resonance imaging and computational fluid dynamics assessment of thoracic aorta blood flow: a literature review

2019 ◽  
Author(s):  
Omar A Jarral ◽  
Matthew K H Tan ◽  
Mohammad Yousuf Salmasi ◽  
Selene Pirola ◽  
John R Pepper ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Cardiovascular Magnetic Resonance ◽  
Magnetic Resonance ◽  
Cardiovascular Magnetic Resonance Imaging ◽  
Phase Contrast ◽  
Aortic Disease ◽  
Flow Patterns ◽  
Health Concern ◽  
Resonance Imaging

Abstract The death rate from thoracic aortic disease is on the rise and represents a growing global health concern as patients are often asymptomatic before acute events, which have devastating effects on health-related quality of life. Biomechanical factors have been found to play a major role in the development of both acquired and congenital aortic diseases. However, much is still unknown and translational benefits of this knowledge are yet to be seen. Phase-contrast cardiovascular magnetic resonance imaging of thoracic aortic blood flow has emerged as an exceptionally powerful non-invasive tool enabling visualization of complex flow patterns, and calculation of variables such as wall shear stress. This has led to multiple new findings in the areas of phenotype-dependent bicuspid valve flow patterns, thoracic aortic aneurysm formation and aortic prosthesis performance assessment. Phase-contrast cardiovascular magnetic resonance imaging has also been used in conjunction with computational fluid modelling techniques to produce even more sophisticated analyses, by allowing the calculation of haemodynamic variables with exceptional temporal and spatial resolution. Translationally, these technologies may potentially play a major role in the emergence of precision medicine and patient-specific treatments in patients with aortic disease. This clinically focused review will provide a systematic overview of key insights from published studies to date.

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