Analysis of ASD parameters
The ASD parameters in this study including the maximum diameter, the
minimum diameter, circular index (the ratio of the maximal to minimal
diameters, ASD shape were distinguished by the circular index, round ASD
defined as those patients with a circular index less than 1.4 and the
oval shape defined as those with a circular index 1.4 or
greater)13, and circumference. All the measurements
taken on the 2D-TEE images and 3D-TEE images were in the same portion of
the cardiac cycle when the size appeared largest, typically
isovolumetric diastole, which is the same frame image for
post-processing and 3D printing. As to the measurement of 2D-TEE images,
the bi-atrial view, the aortic root short axis view and the apical
four-chamber view were regarded as the standard echocardiographic
measurement section,the defect was measured in each of these views and
the maximum diameter and the minimum diameter was determined. For 3D-TEE
measurements, the angle was carefully adjusted on the multiplanar
reconstruction images to identify the largest plane, the longitudinal
planes of the maximal and minimal ASD dimensions were identified using
guidance on the en face image of the ASD, and the size parameters were
measured on the longitudinal planes. When came to the 3D ASD models, the
maximum diameter and the minimum diameter were measured by vernier
caliper directly. A soft aluminum wire was used to shape the ASD, unfold
the soft aluminum wire and the length measured by a vernier caliper was
regarded as the circumference of ASD. All the measurements of ASD from
the three methods were independently performed without knowing the
results of others.