SummaryMagnetic resonance imaging was performed in 26 patients who underwent a modified Fontan procedure. Their age ranged from 1.8 to 31 years with a mean of 12.2 years. A valveless anastomosis was performed between the right atrium and the rudimentary right ventricle in 12 patients and between the right atrium and the pulmonary arteries in 10 patients. A cavopulmonary connection was established in the remaining four patients. Spin echo and gradient echo scans of the heart were performed in orthogonal and angulated projections. The cross-sectional area of the atrioventricular, atriopulmonary or cavopulmonary anastomoses was measured using diameters in two orthogonal imaging planes. Recordings were examined for the presence of right atrial thrombosis, the site of drainage of the coronary sinus, compression of the pulmonary veins, as well as for the presence and extent of pericardial effusions. Cine recordings were used for the assessment of the pattern of flow within the right atrium. The cross-sectional area of the anastomoses could be determined in 24 of 26 patients. This was not statistically different between patients with different surgical procedures. Patients with a cavopulmonary connection, however, tended to have a smaller anastomosis (mean 1.4 cm2/m2BSA, S.D. 0.62) than patients with atrioventricular (mean 3.0 cm2/m2, S.D. 2.1) or atriopulmonary (2.4 cm2/m2, S.D. 1.1) connections. When compared to normal values for the size of the tricuspid valve, the size of the anastomosis was within the normal range in only four patients, it was larger in one and smaller in 19 patients. There were signs of right atrial thromboses in the scans in eight of 26 patients, as observed by two independent investigators. The site of drainage of the coronary sinus was imaged in 20 of 26 patients and was in accordance with the description of surgical procedure in eight. Compression of the right pulmonary veins by an enlarged right atrium was present in seven patients. This was severe in two children. Presence and extent of pericardial effusions could be adequately assessed in 11 of26 patients. Systolic regurgitation from the rudimentary right ventricle into the right atrium was shown in eight of 12 patients with an atrioventricular valveless anastomosis. Cine recordings revealed slow forward flow from the right atrium into the pulmonary arteries in seven of 22 patients, and there was a markedly altered pattern of intraatrial flow in two patients with anomalous systemic venous connections. Magnetic resonance imaging allows adequate examination of right atrial anatomy, determination of the size of the anastomosis with the pulmonary arteries, and semiquantitative assessment of pulmonary blood flow in the majority of patients after a modified Fontan procedure.
Giant right atrial appendage aneurysm: Diagnosis with cardiac magnetic resonance imaging
