scholarly journals Aliased Flow Signal Planimetry by Cardiovascular Magnetic Resonance Imaging for Grading Aortic Stenosis Severity: A Prospective Pilot Study

2021 ◽  
Vol 8 ◽  
Author(s):  
Cesare Mantini ◽  
Mohammed Y. Khanji ◽  
Emilia D'Ugo ◽  
Marzia Olivieri ◽  
Cristiano Giovanni Caputi ◽  
...  
Keyword(s):  
Cardiovascular Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aortic Stenosis ◽  
Phase Contrast ◽  
Continuity Equation ◽  
Intraclass Correlation ◽  
Invasive Technique ◽  
Effective Orifice Area ◽  
Contrast Imaging ◽  
Orifice Area

Objectives: Transthoracic echocardiography (TTE) is the standard technique for assessing aortic stenosis (AS), with effective orifice area (EOA) recommended for grading severity. EOA is operator-dependent, influenced by a number of pitfalls and requires multiple measurements introducing independent and random sources of error. We tested the diagnostic accuracy and precision of aliased orifice area planimetry (AOAcmr), a new, simple, non-invasive technique for grading of AS severity by low-VENC phase-contrast cardiovascular magnetic resonance (CMR) imaging.Methods: Twenty-two consecutive patients with mild, moderate, or severe AS and six age- and sex-matched healthy controls had TTE and CMR examinations on the same day. We performed analysis of agreement and correlation among (i) AOAcmr; (ii) geometric orifice area (GOAcmr) by direct CMR planimetry; (iii) EOAecho by TTE-continuity equation; and (iv) the “gold standard” multimodality EOA (EOAhybrid) obtained by substituting CMR LVOT area into Doppler continuity equation.Results: There was excellent pairwise positive linear correlation among AOAcmr, EOAhybrid, GOAcmr, and EOAecho (p < 0.001); AOAcmr had the highest correlation with EOAhybrid (R2 = 0.985, p < 0.001). There was good agreement between methods, with the lowest bias (0.019) for the comparison between AOAcmr and EOAhybrid. AOAcmr yielded excellent intra- and inter-rater reliability (intraclass correlation coefficient: 0.997 and 0.998, respectively).Conclusions: Aliased orifice area planimetry by 2D phase contrast imaging is a simple, reproducible, accurate “one-stop shop” CMR method for grading AS, potentially useful when echocardiographic severity assessment is inconclusive or discordant. Larger studies are warranted to confirm and validate these promising preliminary results.

scholarly journals Cardiovascular magnetic resonance phase contrast imaging

2015 ◽  
Vol 17 (1) ◽  
Author(s):  
Krishna S. Nayak ◽  
Jon-Fredrik Nielsen ◽  
Matt A. Bernstein ◽  
Michael Markl ◽  
Peter D. Gatehouse ◽  
...  
Keyword(s):  
Cardiovascular Magnetic Resonance ◽  
Magnetic Resonance ◽  
Phase Contrast ◽  
Phase Contrast Imaging ◽  
Contrast Imaging

scholarly journals Application of the Proximal Isovelocity Surface Area Method for Estimation of the Effective Orifice Area in Aortic Stenosis

2021 ◽  
Author(s):  
Masahiro Nakabachi ◽  
Hiroyuki Iwano ◽  
Michito Murayama ◽  
Hisao Nishino ◽  
Shinobu Yokoyama ◽  
...  
Keyword(s):  
Aortic Stenosis ◽  
Flow Velocity ◽  
Surface Area ◽  
Continuity Equation ◽  
Ventricular Outflow Tract ◽  
Left Ventricular ◽  
Effective Orifice Area ◽  
Orifice Area ◽  
Proximal Isovelocity Surface Area ◽  
The Difference

Abstract Purpose: Because existence of high flow velocity at the left ventricular outflow tract (LVOT) potentially causes an overestimation of effective orifice area (EOA) by continuity equation in aortic stenosis (AS), we tested the proximal isovelocity surface area (PISA) method as an alternative tool for AS.Methods: EOA was calculated using the continuity equation (EOACont) and PISA method (EOAPISA), respectively, in 114 patients with at least moderate AS. The geometric orifice area (GOA) was also measured in 51 patients who also underwent three-dimensional transesophageal echocardiography (TEE). Patients were divided into two groups according to the median LVOT flow velocity.Results: Feasibility of EOAPISA was 95% in the 114 patients. While there was a strong correlation between EOACont and EOAPISA, EOACont was greater than EOAPISA especially in patients with high LVOT velocity. In TOE cohort, both EOACont and EOAPISA similarly correlated with GOA. However, a fixed bias, which is supposed to exist in AS, was observed only between EOAPISA and GOA with smaller EOAPISA than GOA. The difference between EOACont and GOA was significantly greater with a larger EOACont relative to GOA in patients with high LVOT velocity than in those without (0.16±0.25 vs -0.07±0.10 cm2, P<0.001). In contrast, the difference between EOAPISA and GOA was consistent in both groups (-0.07±0.12 vs -0.07±0.15 cm2, P = 0.936). Conclusion: The PISA method was applied to estimate EOA of AS. EOAPISA could be an alternative parameter for AS severity grading in patients with high LVOT velocity in whom EOACont would overestimate the orifice area.

scholarly journals Accuracy of stroke volume measurement with phase-contrast cardiovascular magnetic resonance in patients with aortic stenosis

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Ezequiel Guzzetti ◽  
Hugo-Pierre Racine ◽  
Lionel Tastet ◽  
Mylène Shen ◽  
Eric Larose ◽  
...  
Keyword(s):  
Cardiovascular Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aortic Stenosis ◽  
Stroke Volume ◽  
Phase Contrast ◽  
Strong Predictor ◽  
Volume Measurement ◽  
Left Ventricular ◽  
Volumetric Method ◽  
Flow Measurements

Abstract Background Phase contrast (PC) cardiovascular magnetic resonance (CMR) in the ascending aorta (AAo) is widely used to calculate left ventricular (LV) stroke volume (SV). The accuracy of PC CMR may be altered by turbulent flow. Measurement of SV at another site is suggested in the presence of aortic stenosis, but very few data validates the accuracy or inaccuracy of PC in that setting. Our objective is to compare flow measurements obtained in the AAo and LV outflow tract (LVOT) in patients with aortic stenosis. Methods Retrospective analysis of patients with aortic stenosis who had CMR and echocardiography. Patients with mitral regurgitation were excluded. PC in the AAo and LVOT were acquired to derive SV. LV SV from end-systolic and end-diastolic tracings was used as the reference measure. A difference ≥ 10% between the volumetric method and PC derived SVs was considered discordant. Metrics of turbulence and jet eccentricity were assessed to explore the predictors of discordant measurements. Results We included 88 patients, 41% with bicuspid aortic valve. LVOT SV was concordant with the volumetric method in 79 (90%) patients vs 52 (59%) patients for AAo SV (p = 0.015). In multivariate analysis, aortic stenosis flow jet angle was a strong predictor of discordant measurement in the AAo (p = 0.003). Mathematical correction for the jet angle improved the concordance from 59 to 91%. Concordance was comparable in patients with bicuspid and trileaflet valves (57% and 62% concordance respectively; p = 0.11). Accuracy of SV measured in the LVOT was not influenced by jet eccentricity. For aortic regurgitation quantification, PC in the AAo had better correlation to volumetric assessments than LVOT PC. Conclusion LVOT PC SV in patients with aortic stenosis and eccentric jet might be more accurate compared to the AAo SV. Mathematical correction for the jet angle in the AAo might be another alternative to improve accuracy.

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.

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