Introduction CMRI has been shown to be reliable in the post operative assessment of aortic coarctation. [1] In a previous study MRI measurements of aortic diameter correlated well with angiographically determined aortic diameters. [2] Limited data however exists for measurements of the thoracic aorta and main pulmonary artery in normal adults. Assessment of Aortic Disease Three dimensional contrast enhanced MR angiography (3D CE MRA) is the most widely accepted method for the assessment and follow-up of thoracic aortic disease using MRI. –This requires the use...

Participants 49 normal adult volunteers Males = 23 (mean age 32, range 22 to 60 years) Females = 26 (mean age 33, range 22 to 55 years) Technique Breath hold 2D ECG gated SSFP images of the thoracic aorta were obtained in a sagittal oblique view; perpendicular to the ascending aorta at the level of the aortic sinuses; and of the LVOT. (Sidebar Figures 4-6). 3D sagittal oblique images of the thoracic aorta were obtained using a free breathing navigator assisted ECG gated SSFP technique....

Results Overall, inter-observer agreement for all measurements was excellent with intra-class correlation coefficient for all measurements of 0.978. Correlation at each region has been tabulated. (Table 1). When comparing 2D and 3D techniques, 3 regions demonstrated a statistically significant difference: Annulus (p = 0.000 ) Ascending aorta at the level of RPA (p = 0.000 ) Arch of aorta between LC and LSC. (p = 0.001) The annulus was particularly difficult to measure in the 3D image acquisition due to substantial artifact. Although these regions...

Conclusion Normal values for the adult thoracic aorta and the main pulmonary artery were established using cardiac MRI. Although overall a statistically significant difference was demonstrated between 2D and 3D aorta measurements, the average difference between techniques was in the order of a fraction of a millimeter. In clinical practice, this would not be considered significant.

Dr A. Mohamed Radiology Registrar Prince Charles Hospital/Princess Alexandra Hospital. Email: [email protected]

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