Role of plain radiography and CT angiography in the evaluation of obstructed total anomalous pulmonary venous connection.

BACKGROUND: Obstructed total anomalous pulmonary venous connection (TAPVC) is frequently misdiagnosed as pulmonary disease and without operative correction early death is common. It is important to make a correct diagnosis before surgery.
OBJECTIVE: The purpose of this study was to describe the chest radiographic features of obstructed TAPVC and compare CT angiography with transthoracic echocardiography in the evaluation of obstructed TAPVC.
MATERIALS AND METHODS: Eighteen children with obstructed TAPVC were assessed. Their clinical and imaging data were retrospectively reviewed. The characteristic radiographic findings were analyzed and compared with surgical results, and the diagnostic accuracy of CT angiography and transthoracic echocardiography was evaluated in terms of pulmonary venous drainage and obstruction detection.
RESULTS: The common radiographic features included pulmonary venous congestion or edema or both (16 of 18 cases, 89%), and absence of cardiomegaly (12 of 18 cases, 67%). CT angiography correctly diagnosed TAPVC and clearly revealed the draining sites in all children (five with supracardiac TAPVC, three with cardiac TAPVC, eight with infracardiac TAPVC and two with mixed TAPVC). The diagnostic agreement between CT angiography and surgery was 100%. Transthoracic echocardiography only correctly revealed the draining sites in 11 children (5 with supracardiac TAPVC, 2 with cardiac TAPVC and 4 with infracardiac TAPVC). The diagnostic agreement between transthoracic echocardiography and surgery was 61%. The diagnostic accuracy of CT angiography was higher than that of transthoracic echocardiography (P = 0.0156). Thirty-four sites of obstruction were correctly detected by CT angiography (11 in the mediastinum, 1 at the diaphragmatic level, 9 below the diaphragm and 13 stenotic individual pulmonary veins in the lung). The diagnostic agreement between CT angiography and surgery was 92%. Transthoracic echocardiography only correctly detected 15 sites of obstruction (11 in the mediastinum, 1 at the diaphragmatic level and 3 below the diaphragm). The diagnostic agreement between transthoracic echocardiography and surgery was 41%. The rate of detection for sites of obstruction with transthoracic echocardiography was much lower than that of CT angiography (P = 0.0002).
CONCLUSION: In children with obstructed TAPVC, plain radiographs usually show a characteristic pattern of pulmonary venous congestion or edema, or both, and a normal cardiac silhouette. CT angiography is superior to transthoracic echocardiography in the evaluation of pulmonary venous drainage and obstruction, especially in children with infracardiac and mixed TAPVC.