The Clinical Significance of Aortic Compliance and Its Assessment with Magnetic Resonance Imaging

Metafratzi, Zafiria M.; Efremidis, Stavros C.; Skopelitou, Antigoni S.; Roos, Albert de

doi:10.1081/jcmr-120016386

Cited by 66 publications

(48 citation statements)

References 47 publications

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“…In our study, PWV was considered as the distance between two points divided by the time needed for the pulse wave to cover this distance. Similar methods also using magnetic resonance imaging have previously been described (13,16,17,32,33). The principal difference between the proposed methods is the determination of the transit time for the flow wave to propagate from one point to another.…”

Section: Discussionmentioning

confidence: 99%

“…MR imaging techniques are particularly attractive to study the aortic elasticity of the thoracic aorta (11)(12)(13)16,17,23), because they allow direct and noninvasive evaluation of aortic stiffness in addition to morphological evaluation and measurements of the total thoracic aorta.…”

Section: Discussionmentioning

confidence: 99%

“…Groenink et al (13) used the point where the flow reached half of its maximum value. Some authors considered the foot of the flow wave, corresponding the step ascent of the flow wave at the beginning of the systole (17,32). In our case, the matching between the two curves using a least squares method permits to calculate the transit time by using the whole shape of the two curves, avoiding to restrict the analysis to a few points of the curves.…”

Section: Discussionmentioning

confidence: 99%

“…The aortic compliance can be defined as the change in arterial blood volume within an aortic segment caused by a given change in arterial blood pressure (8,17). Practically, the arterial blood volume is defined as the aortic cross-sectional area multiplied by the slice thickness.…”

Section: Image Analysismentioning

confidence: 99%

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Compliance and pulse wave velocity assessed by MRI detect early aortic impairment in young patients with mutation of the smooth muscle myosin heavy chain

Lalande

Kien

Walker

et al. 2008

Magnetic Resonance Imaging

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Purpose:To evaluate aortic elasticity with MRI on young asymptomatic individuals with mutation of the smooth muscle myosin heavy chain in whom aortic enlargement is not present. Materials and Methods:Aortic compliance, aortic distensibility, and pulse wave velocity (PWV) were semiautomatically measured from MRI in 8 asymptomatic subjects having a mutation of the MYH11 gene (Mϩ) and 21 nonmutated relatives (MϪ) of similar age, sex, and blood pressure characteristics.Results: Despite a similar aortic diameter in both groups, the aortic compliance and distensibility were significantly lower in Mϩ subjects compared with MϪ (0.84 Ϯ 0.33 versus 2.03 Ϯ 0.54 mm 2 /mmHg, 1.18 Ϯ 0.62 10 Ϫ3 versus 5.11 Ϯ 1.58 10 Ϫ3 mmHg Ϫ1 , respectively), and PWV was significantly higher (5.35 Ϯ 1.53 versus 3.60 Ϯ 0.64 m.s Ϫ1 ). A threshold aortic compliance value of 1.3 mm 2 /mmHg separated the two groups. The receiver operating characteristics curve analysis indicated an optimal threshold of 2.9 10 Ϫ3 mmHg Ϫ1 for aortic distensibility (sensitivity: 87.5%, specificity: 90%), and of 4.4 m.s Ϫ1 for PWV (sensitivity: 75%, specificity: 100%). Conclusion:Young asymptomatic adults with MYH11 mutation have an aortic compliance impairment which is not detectable by the sole measurement of the aortic size. Aortic compliance measurement might be part of routine examination in patients suspected of inherited aortic disease even with a normal aortic diameter.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Image Analysismentioning

confidence: 99%

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Compliance and pulse wave velocity assessed by MRI detect early aortic impairment in young patients with mutation of the smooth muscle myosin heavy chain

Lalande

Kien

Walker

et al. 2008

Magnetic Resonance Imaging

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“…To provide a noninvasive estimate of PWV, phase contrast (PC) MRI has been applied in a number of in vivo studies determining blood flow based on flow waveform measurements in single two-dimensional (2D) planes transecting the aorta (8)(9)(10). For PWV estimation, typically transit-time methods are employed estimating temporal differences of specific features of blood flow waveforms, e.g., time from foot to foot or peak to peak, between two locations of the vessel with known distance (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). However, the precision of this method highly depends on the exact calculation of flow difference and distance between only two measuring points (16,25,26).…”

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confidence: 99%

Estimation of global aortic pulse wave velocity by flow‐sensitive 4D MRI

Markl

Wallis

Brendecke

et al. 2010

Magnetic Resonance in Med

112

114

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The aim of this study was to determine the value of flow-sensitive four-dimensional MRI for the assessment of pulse wave velocity as a measure of vessel compliance in the thoracic aorta. Findings in 12 young healthy volunteers were compared with those in 25 stroke patients with aortic atherosclerosis and an age-matched normal control group (n 5 9). Results from pulse wave velocity calculations incorporated velocity data from the entire aorta and were compared to those of standard methods based on flow waveforms at only two specific anatomic landmarks. Global aortic pulse wave velocity was higher in patients with atherosclerosis (7.03 6 0.24 m/ sec) compared to age-matched controls (6.40 6 0.32 m/sec). Both were significantly (P < 0.001) increased compared to younger volunteers (4.39 6 0.32 m/sec). Global aortic pulse wave velocity in young volunteers was in good agreement with previously reported MRI studies and catheter measurements. Estimation of measurement inaccuracies and error propagation analysis demonstrated only minor uncertainties in measured flow waveforms and moderate relative errors below 16% for aortic compliance in all 46 subjects. These results demonstrate the feasibility of pulse wave velocity calculation based on fourdimensional MRI data by exploiting its full volumetric coverage, which may also be an advantage over standard two-dimensional techniques in the often-distorted route of the aorta in patients with atherosclerosis. Magn Reson Med 63:1575-1582, 2010. V C 2010 Wiley-Liss, Inc. Key words: pulse wave velocity; compliance; phase contrast; atherosclerosis; aorta Increased pulse wave velocity (PWV) as a measure of aortic stiffness is an important marker for both agerelated changes in aortic compliance and the presence of atherosclerosis (1,2) and is an independent predictor of cardiovascular mortality and stroke (3,4). Reliable measurement of PWV is of particular interest for monitoring the progression or regression of vessel compliance during therapy (5,6).Pressure catheter measurements can be considered the gold standard for the assessment of the development of aortic pressure wave, but their use is limited due to the invasiveness of the procedure (7). To provide a noninvasive estimate of PWV, phase contrast (PC) MRI has been applied in a number of in vivo studies determining blood flow based on flow waveform measurements in single two-dimensional (2D) planes transecting the aorta (8-10). For PWV estimation, typically transit-time methods are employed estimating temporal differences of specific features of blood flow waveforms, e.g., time from foot to foot or peak to peak, between two locations of the vessel with known distance (11-24). However, the precision of this method highly depends on the exact calculation of flow difference and distance between only two measuring points (16,25,26).Methodological improvements include a more continuous evaluation along a vessel center line and cross-correlation (XCor) analysis for the estimation of waveform delays, which improved the accuracy of PWV...

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Analysis of pulse wave velocity in the thoracic aorta by flow‐sensitive four‐dimensional MRI: Reproducibility and correlation with characteristics in patients with aortic atherosclerosis

Markl

Wallis

Strecker

et al. 2012

Magnetic Resonance Imaging

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Purpose: To measure aortic pulse wave velocity (PWV) using flow-sensitive four-dimensional (4D) MRI and to evaluate test-retest reliability, inter-and intra-observer variability in volunteers and correlation with characteristics in patients with aortic atherosclerosis.Materials and Methods: Flow-sensitive 4D MRI was performed in 12 volunteers (24 6 3 years) and 86 acute stroke patients (68 6 9 years) with aortic atherosclerosis. Retrospectively positioned 28 6 4 analysis planes along the entire aorta (inter-slice-distance ¼ 10 mm) and frame wise lumen segmentation yielded flow-time-curves for each plane. Global aortic PWV was calculated from timeshifts and distances between the upslope portions of all available flow-time curves.Results: Inter-and intra-observer variability of PWV measurements in volunteers (7% and 8%) was low while test-retest reliability (22%) was moderate. PWV in patients was significantly higher compared with volunteers (5.8 6 2.9 versus 3.8 6 0.8 m/s; P ¼ 0.02). Among 17 patient characteristics considered, statistical analysis revealed significant (P < 0.05) but low correlation of PWV with age (r ¼ 0.25), aortic valve insufficiency (r ¼ 0.29), and pulse pressure (r ¼ 0.28). Multivariate modeling indicated that aortic valve insufficiency and elevated pulse pressure were significantly associated with higher PWV (adjusted R 2 ¼ 0.13). INCREASED PULSE WAVE velocity (PWV) is a measure of aortic stiffness and closely associated with atherosclerosis. A recent meta-analysis revealed that increased PWV and thus reduced aortic compliance is a strong predictor of future cardiovascular events and all-cause mortality. Moreover, the authors identified that an increase in aortic PWV by 1 m/s corresponded to an age-, sex-, and risk factor-adjusted risk increase of ca. 15% in total cardiovascular events (1). Reliable measurement of PWV is of particular interest for monitoring vessel compliance during therapy (2,3). Carotid-femoral PWV using tonometry is the current reference standard to measure aortic compliance (4). This method, however, does not focus on compliance of the thoracic aorta. Instead, wall characteristics of both the abdominal aorta and the carotid and femoral arteries are also included. Time-resolved (CINE) Phase contrast (PC) MRI provides a noninvasive estimate of PWV based on flow waveform measurements in analysis planes and allows focusing on the region of interest in stroke patients, i.e., the thoracic aorta (5). Transit-time (TT) methods are typically used estimating temporal differences of specific flow waveforms features, e.g., timing differences of the foot of the waveform between two locations with known distance (6-14). Alternatively, PWV was calculated using targeted excitation of the vessel of interest in Conclusion

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The Clinical Significance of Aortic Compliance and Its Assessment with Magnetic Resonance Imaging

Cited by 66 publications

References 47 publications

Compliance and pulse wave velocity assessed by MRI detect early aortic impairment in young patients with mutation of the smooth muscle myosin heavy chain

Compliance and pulse wave velocity assessed by MRI detect early aortic impairment in young patients with mutation of the smooth muscle myosin heavy chain

Estimation of global aortic pulse wave velocity by flow‐sensitive 4D MRI

Analysis of pulse wave velocity in the thoracic aorta by flow‐sensitive four‐dimensional MRI: Reproducibility and correlation with characteristics in patients with aortic atherosclerosis

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