Regional assessment of carotid artery pulse wave velocity using compressed sensing accelerated high temporal resolution 2D CINE phase contrast cardiovascular magnetic resonance

Abstract

BackgroundCardiovascular magnetic resonance (CMR) allows for non-invasive assessment of arterial stiffness by means of measuring pulse wave velocity (PWV). PWV can be calculated from the time shift between two time-resolved flow curves acquired at two locations within an arterial segment. These flow curves can be derived from two-dimensional CINE phase contrast CMR (2D CINE PC CMR). While CMR-derived PWV measurements have proven to be accurate for the aorta, this is more challenging for smaller arteries such as the carotids due to the need for both high spatial and temporal resolution. In this work, we present a novel method that combines retrospectively gated 2D CINE PC CMR, high temporal binning of data and compressed sensing (CS) reconstruction to accomplish a temporal resolution of 4 ms. This enables accurate flow measurements and assessment of PWV in regional carotid artery segments.MethodsRetrospectively gated 2D CINE PC CMR data acquired in the carotid artery was binned into cardiac frames of 4 ms length, resulting in an incoherently undersampled ky-t-space with a mean undersampling factor of 5. The images were reconstructed by a non-linear CS reconstruction using total variation over time as a sparsifying transform. PWV values were calculated from flow curves by using foot-to-foot and cross-correlation methods. Our method was validated against ultrasound measurements in a flow phantom setup representing the carotid artery. Additionally, PWV values of two groups of 23 young (30 ± 3 years, 12 [52%] women) and 10 elderly (62 ± 10 years, 5 [50%] women) healthy subjects were compared using the Wilcoxon rank-sum test.ResultsOur proposed method produced very similar flow curves as those measured using ultrasound at 1 ms temporal resolution. Reliable PWV estimation proved possible for transit times down to 7.5 ms. Furthermore, significant differences in PWV values between healthy young and elderly subjects were found (4.7 ± 1.0 m/s and 7.9 ± 2.4 m/s, respectively; p < 0.001) in accordance with literature.ConclusionsRetrospectively gated 2D CINE PC CMR with CS allows for high spatiotemporal resolution flow measurements and accurate regional carotid artery PWV calculations. We foresee this technique will be valuable in protocols investigating early development of carotid atherosclerosis.Electronic supplementary materialThe online version of this article (10.1186/s12968-018-0499-y) contains supplementary material, which is available to authorized users.

4D flow imaging with UNFOLD in a reduced FOV

“…Furthermore, the joint technique might prove useful to reduce motion artifacts, such as swallowing artifacts in carotid artery imaging, while preserving high temporal resolutions. Combining retrospective electrocardiogram triggering with compressed sensing, temporal resolutions with Δ t < 2 TR have been shown for 2D cine phase‐contrast MRI . Similarly, integrating 2DRF pulses into a retrospectively electrocardiogram‐triggered 4D flow sequence would allow reconstructing 2DRF 4D flow MRI with Δ t < 4 TR.…”

“…Combining retrospective electrocardiogram triggering with compressed sensing, temporal resolutions with Δt < 2 TR have been shown for 2D cine phase-contrast MRI. 36 Similarly, integrating 2DRF pulses into a retrospectively electrocardiogram-triggered 4D flow sequence would allow reconstructing 2DRF 4D flow MRI with Δt < 4 TR. Using parallel transmission 37,38 to decrease 2DRF pulse durations 39 is another option to increase temporal resolutions, which would additionally decrease the excitation sensitivity to magnetic field inhomogeneities.…”

Evaluation of tensile stress in carotid artery: evidence from ultrasonography

“…However, the arteries are of viscoelastic properties and exhibit the nonlinear stress-stain relations [23]. Several new non-invasive techniques have been used to study arterial elasticity, such as dimensional speckle-tracking imaging [24], ultrasonic radiofrequency tracking [25] and shear wave elastography [26,27]. However, in vivo, it is difficult to study the arterial viscidity due to its complex temporal changing behavior.…”

Ultrasound Assessment of Tensile Stress in Carotid Arteries of Healthy Human Subjects with Varying Age

“…However, the arteries are of viscoelastic properties and exhibit the nonlinear stress-stain relations [24]. Several new non-invasive techniques have been used to study arterial elasticity, such as dimensional speckle-tracking imaging [25], ultrasonic radiofrequency tracking [26] and shear wave elastography [27][28][29]. However, in vivo, it is difficult to study the arterial viscidity due to its complex temporal changing behavior.…”