Use of non-invasive phase contrast magnetic resonance imaging for estimation of atrial septal defect size and morphology: a comparison with transesophageal echo.
BACKGROUND
Transesophageal echocardiography (TEE) is a trusted method of sizing atrial septal defect (ASD) prior to percutaneous closure but is invasive, uncomfortable, and may carry a small risk of morbidity and mortality. Magnetic resonance imaging (MRI) may be useful non-invasive alternative in such patients who refuse or are unable to tolerate TEE and may provide additional information on the shape of the A0SD.


OBJECTIVE
To validate the accuracy of ASD sizing by MRI compared with TEE.


METHODS
Twelve patients (mean age 30 years; range 11-60 years) scheduled for ASD closure underwent TEE, cine balanced fast field echo MRI (bFFE-MRI) in four-chamber and sagittal views and phase-contrast MRI (PC-MRI) with reconstruction using the two orthogonal planes of T2-weighted images as planning. The average of the three longest measurements for all imaging modalities was calculated for each patient.


RESULTS
Mean maximum ASD length on TEE was 18.8 +/- 4.6 mm, mean length by bFFE-MRI was 20.0 +/- 5.0 mm, and mean length by PC-MRI was 18.3 +/- 3.6 mm. The TEE measurement was significantly correlated with the bFFE-MRI and PC-MRI measurements (Pearson r = 0.69, p = 0.02 and r = 0.59, p = 0.04, respectively). The mean difference between TEE and bFFE-MRI measurements was -1.2mm (95% CI: -3.7, 1.3) and between TEE and PC-MRI was 0.5 mm (95% CI: -1.9, 2.9). Bland-Altman analysis also determined general agreement between both MRI methods and TEE. The ASDs were egg-shaped in two cases, circular in 1 patient and oval in the remaining patients.


CONCLUSIONS
ASD sizing by MRI using bFFE and phase-contrast protocols correlated well with TEE estimations. PC-MRI provided additional information on ASD shapes and proximity to adjacent structures.
Piaw
Chin Sze
CS
Department of Cardiology, Sarawak General Hospital, Jalan Tun Ahmad Zaidi Adruce, Kuching, 93580, Sarawak, East Malaysia.
Kiam
Ong Tiong
OT
Rapaee
Annuar
A
Khoon
Liew Chee
LC
Bang
Liew Houng
LH
Ling
Chan Wei
CW
Samion
Hasri
H
Hian
Sim Kui
SK
D000293:Adolescent; D000328:Adult; D002648:Child; D017548:Echocardiography, Transesophageal; D005260:Female; D006344:Heart Septal Defects, Atrial / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies