Contrast-enhanced MR angiography of pulmonary venous abnormalities in children

Abstract

Background. Echocardiography and X-ray angiography have been considered as gold standards for evaluation of pulmonary venous abnormalities. However, each technique has its own limitations, such as limitation in visualization of the pulmonary veins within the lungs by echocardiography, and the invasive nature of and use of ionizing radiation in X-ray angiography. Contrast-enhanced MR angiography (MRA) is a fast noninvasive method of visualization of the vessels including the pulmonary arteries and veins.

Objectives. To evaluate the utility of contrast-enhanced MRA in the evaluation of pulmonary venous abnormalities in pediatric patients and to compare its diagnostic accuracy with that of transthoracic echocardiography.

Materials and methods. In 30 pediatric patients 31 contrast-enhanced MRA studies were performed for evaluation of pulmonary venous abnormalities. Each of 124 pulmonary veins was evaluated for site of connection, course within the lung, presence of obstruction, and topographic relationship with the adjacent structures. The findings of MRA were compared with echocardiographic findings for 116 veins in 29 studies in 28 patients.

Results. Contrast-enhanced MRA visualized 99% (123 of 124) of the pulmonary veins investigated, while echocardiography visualized 89% (103 of 116). Exact agreement was found between the two methods in 72% of the veins with a weighted kappa of 0.60 (0.47–0.73, 95% CI). Echocardiography failed to diagnose an abnormal connection in 2 of 15 pulmonary veins, a discrete stenosis in 2 of 19 veins, and diffuse hypoplasia in 10 of 14 veins. In 29% of patients, MRA made the uncertain echocardiographic findings clear. In another 29%, MRA provided a new diagnosis.

Conclusions. Contrast-enhanced MRA is a powerful, safe, and accurate fast-imaging technique for the anatomical evaluation of pulmonary venous abnormalities. MRA may obviate the need for conventional X-ray angiography. Cardiac catheterization may be reserved for those patients in whom pulmonary vascular resistance needs to be determined.