Cardiac magnetic resonance imaging of atrial septal defect for transcatheter closure

The location, size of the defect and age of the patient are the major determining factors for transcatheter closure of an atrial septal defect (ASD). The precise shape and anatomy surrounding the defect cannot always be understood by the traditional transesophageal (TEE) echocardiographic technique.

The authors compared the measurement of ASD size and atrial septal rim using cardiac Magnetic Resonance Imaging (MRI) and TEE to the balloon sizing technique and device size.

Patients having an ASD which met established criteria were selected for evaluation with cardiac MRI and TEE for a closure procedure. Comparison of the ASD imaging and sizing between the different methods was made.

There were 22 patients who had complete transcatheter closure. The mean age and standard deviation of the patients was 33.2+/-15.1 (8-67) years old. The mean weight of the patients was 51.6+/-13.1 (20-99) kg. The average cardiac MRI measurement of the ASD was 24.9+/-6.4 mm compared to the TEE measurement of 20.8+/-5.5 mm. The transcatheter balloon measurement of the ASD was 25.2+/-6.9 (11-36) mm and the device closure size was 24.8+/-6.6 (11-36) mm. The correlation coefficient of cardiac MRI to device closure size was r = 0.784 (p < 0.001) when compared to TEE measurement to device closure size; r = 0.761 (p = 0.001).

The authors demonstrated the capability of the cardiac MRI in assessment of the ASD morphology and anatomy for transcatheter closure of the ASD with an Amplatzer Septal Occluder. Cardiac MRI can provide information about the type, location, size of the defect and direct visualization of the atrial septum anatomy. This detailed information enabled us to provide a safer, more effective application of the ASD occluder.