Aortic dimensions in Turner's syndrome: two-dimensional echocardiography versus magnetic resonance imaging

Patients with Turner's syndrome have an increased risk of cardiac death caused by aortic disease. Consensus has not been reached about the best method to image the aorta in this syndrome.

This present study aimed: (i) to evaluate thoracic and abdominal aortic dimensions by two-dimensional echo (2-DE) and magnetic resonance imaging (MRI) and (ii) to assess agreement between 2-DE and MRI measurements.

Among 75 kariotypically proven Turner's syndrome patients, 59 (79%) (mean age: 22 +/- 7 years) underwent a 2-DE and an MRI study of the thoracic and proximal abdominal aorta. The aortic root (AR), the sino-tubular aortic junction (STJ), the first part of the ascending thoracic aorta (AscTA), the aortic arch (AArch), the descending thoracic aorta (DTAp) a few centimetres below the isthmus and the abdominal aorta (AbA) were analysed. The Bland and Altman method and Lin's concordance correlation coefficient were utilized to compare 2-DE and MRI aortic dimensions.

Compared to MRI, feasibility of aortic imaging by 2-DE was identical at AR level, but lower when measuring distal aorta (88% at DTAp and 91.5% at AbA level versus 100%). The 2-DE and MRI showed a very slight difference between measurements and a high concordance correlation coefficient at the level of AR and AscTA; correlations were weaker at the other aortic levels. Absolute differences calculated at each measurement level showed that concordance (defined as differences within 1 mm between 2-DE and MRI absolute measures) was highest at AR (45.6%) and AscTA (28%) level and lowest at STJ (12.2%) level. The 2-DE overestimated aortic arch diameters in approximately 70% of cases, whereas at the remaining aortic levels MRI measurements were usually 1 mm higher compared to the corresponding 2-DE values.

Concordance between 2-DE and MRI was found to be very good at the AR and AscTA levels. Because the risk of aortic complication is higher when AR and proximal thoracic aorta are dilated, 2-DE may be considered a useful method to screen for aortic disease and a good choice to follow proximal aortic dimensions over time in Turner's syndrome patients.