Comparison of two- and three-dimensional transthoracic echocardiography for measurement of aortic annulus diameter in children.
BACKGROUND
Accurate evaluation of aortic root geometry is necessary in congenital aortic valve lesions in children, to guide surgical or angiographical intervention.


OBJECTIVE
To compare aortic annulus diameters measured by two- and three-dimensional transthoracic echocardiography (2D- and 3D-TTE), to determine the feasibility and reproducibility of 3D imaging and assess the dynamic changes during the cardiac cycle.


METHODS
Thirty children without heart disease were prospectively included. Two orthogonal aortic annulus diameters were measured offline using multiplanar reconstruction in diastole and in systole and were compared with the measurement of the aortic annulus diameter by 2D-TTE.


RESULTS
Mean age was 11±3.6 years. Feasibility of 3D imaging was 100%. The coefficients of intra- and interobserver variability were 3.5% and 6%, respectively. The 2D mean diameter was significantly smaller than the 3D maximum diameter in systole (1.94 vs. 2.01mm; p=0.005). 2D and 3D measurements were well correlated (p<0.0001). The maximum and minimum diameters in 3D were significantly different both in systole and in diastole (p<0.001) underlining an aortic annulus eccentricity. The mean aortic annulus diameters were not significantly different between systole and diastole, with important individual variability during the cardiac cycle.


CONCLUSIONS
This study demonstrated the feasibility and reproducibility of 3D-TTE for the assessment of the aortic annulus diameter in a normal paediatric population. Because of an underestimation of the maximum diameter by 2D-TTE and the asymmetry of the aortic annulus, 3D measurements could be important before percutaneous aortic valvuloplasty or surgical replacement.
Paediatric Cardiology Unit, Children's Hospital, Toulouse University Hospital, 330, avenue de Grande-Bretagne, TSA 70034, 31059 Toulouse cedex 9, France.
Romain
R
Martin
Sébastien
S
Hascoët
Yves
Y
Dulac
Marianne
M
Peyre
Simon
S
Mejean
Khaled
K
Hadeed
Alexandre
A
Cazavet
Bertrand
B
Leobon
Philippe
P
Acar
D000293:Adolescent; D000367:Age Factors; D001021:Aortic Valve / Q000000981:diagnostic imaging* / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D003971:Diastole; D019560:Echocardiography, Three-Dimensional; D005240:Feasibility Studies; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012016:Reference Values; D015203:Reproducibility of Results; D013599:Systole
2D; 2D-TTE; 3D; 3D-TTE; Anneau aortique; Aortic annulus; Aortic valve; CI; Children; Dmax; Dmin; Pédiatrie; SD; Three-dimensional echocardiography; Two-dimensional echocardiography; Valve aortique; confidence interval; maximum diameter; minimum diameter; standard deviation; three-dimensional; three-dimensional transthoracic echocardiography; two-dimensional; two-dimensional transthoracic echocardiography; Échocardiographie 2D; Échocardiographie 3D