Evaluation of aortic parameters by 4d flow MRI in patients with Marfan syndrome and related syndromes

Introduction

Predicting aortic root dilation and the risk of aortic dissection in Marfan syndrome remains challenging. Established predictive factors primarily include aortic diameter and younger age. However, a more comprehensive understanding of aortic hemodynamic alterations in this population is warranted. 4D magnetic resonance imaging (MRI) offers a non-irradiating approach for assessing hemodynamic parameters.

Objective

This study aimed to assess aortic parameters using 4D flow MRI in young patients diagnosed with Marfan syndrome.

Methods

We prospectively included patients over 12 years old from the “CHU de Toulouse Centre de Référence Marfan” cohort. They underwent MRI with 4D flow sequences and an aortic angiography sequence without contrast agent administration. Pulse wave velocity (PWV) and wall shear stress (WSS) were quantified using Circle CVI software.

Results

Since February 2023, we included 13 patients without history of aortic events, all treated with beta-blockers, with a median age of 18 years old (range: 15 to 39). MRI imaging was successfully conducted in all cases. The addition of 4D flow acquisitions extended the examination time by 15 to 25 min and the post-processing time by 5 to 10 min. The median aortic diameter was 35 mm (range: 32 to 48) and Z-score ranged from +1.2 to +6.1. Both PWV and WSS were quantifiable across all cases: the median PWV measured 5.5 m/s (range: 2.2 to 13.5), while the median WSS was 0.104 Pa (range: 0.074 to 1.590). No correlations were observed between age, body surface area, or aortic diameter with either PWV or WSS (Fig. 1).

Conclusion

A non-invasive, non-irradiating, free-breathing assessment of aortic hemodynamics using 4D flow MRI sequences is feasible in both adolescent and adult patients with Marfan syndrome, albeit with some challenges. However, further studies with larger patient cohorts, comparison with control groups, and long-term follow-up are necessary to determine if this method could serve as a prognostic marker.