Routine Unenhanced 2D MRI for Maximal Segmental Diameters of Thoracic Aorta

Abstract

Background: Increasing demand for aortic dilatation imaging and complicated use of multiplanar image reconstructions (MPR) from 3D images for less experienced users inspired research of unenhanced 2D-MRI in order to reduce need for aortic MPR.Purpose: To research robustness of unenhanced 2D-MRI with no need for MPR from 3D images by comparing maximal axial measurements of thoracic aorta in unenhanced “dark blood” (DB) and “bright blood” (BB) 2D-MRI images vs. contrast enhanced 3D-T1 MR angiography (ce3D-MRA) both in patients with tricuspid (TAV) and bicuspid (BAV) aortic valves. Material and Methods: Prospective study. 68 subjects underwent MRI and US examinations of aorta and were divided into 2 groups: 1) TAV patients: 26 patients, age: 53.3±8.1 years, 14 males and 12 females; 2) BAV patients: 42 patients, age: 30.8±9.8, 31 males and 11 females.Results: Strongest correlation between repeated MRI studies for TAV thoracic aorta segmental measurements was in BB (AS R=0.94, AA R=0.94) as well between BB and US (AS R=0.9, AA R=0.86). Unenhanced techniques in BAV patients revealed statistically significant correlation in all segments (p˂0.05) with strongest correlation in AA (R=0.96) and weakest correlation in AS (R=0.86, influenced by asymmetry of sinuses in BAV). Conclusion: BB correlated better with ce3D-MRA than measurements performed in DB both in TAV and BAV cohorts, especially in the AA. Comparing aortic measurements between US and MRI unenhanced sequences - BB had the strongest correlation in TAV. Our results suggest that there is no strict need for intravenous contrast administration and MPR for routine MRI evaluation of thoracic aorta’s maximal diameters, except for AS in BAV.