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Abstract Objectives Diameter-based aortic assessment does not fully describe interactions among adult aortic remodeling, stroke-volume input, and regional flow organization. This paper aims to assess phase-contrast cardiac MRI of the aortic reservoir–flow coupling across different adult age groups. Methods This single-center observational study included 252 adults undergoing thoracic aortic phase-contrast cardiac Magnetic Resonance Imaging (MRI) on a 3.0-T Siemens MAGNETOM Skyra scanner with an 18-channel abdominal phased-array coil. Participants were stratified as younger adults (18–33 years, n=66), middle-aged adults (34–60 years, n=119), and older adults (>60 years, n=67). Velocity-encoded imaging covered the thoracic aorta with TR 38.88 ms, TE 68.8 ms, flip angle 8°, matrix 256 × 256, FOV 300 mm, spatial resolution 1.4 × 1.4 mm 2 , slice thickness 3 mm, and interslice gap 0.6 mm. Centerline segmentation defined six analysis planes; aortic geometry, LV stroke volume, nSV, velocity, vorticity, and helicity were analyzed using group comparison, regression, and determinant modeling. Results Older adults showed larger aortic volume (176.2 ± 50.8 vs. 114.6 ± 27.1 mL), ascending aortic diameter (33.8 ± 5.8 vs. 28.3 ± 3.5 mm), and lower nSV (0.44 ± 0.15 vs. 0.92 ± 0.18) than younger adults. Velocity and vorticity attenuated regionally, helicity approached zero distally, and nSV was the dominant determinant in later adulthood. Conclusions Phase-contrast cardiac MRI identified a reservoir–flow coupling phenotype characterized by enlarged aortic reservoir volume, reduced relative stroke-volume input, and attenuated systolic flow organization.
Lv et al. (Wed,) studied this question.