In response to the article by Andrew J. Powell, Taylor Chung, Michael J. Landzberg & Tal Geva - Accuracy of MRI evaluation of pulmonary blood supply in patients with complex pulmonary stenosis or atresia

Detailed imaging of pulmonary artery (PA) anatomy and significant aorto-pul monary collaterals (APCs) is crucial for surgical planning and follow-up in patients with complex congenital heart disease (CHD) and pulmonary stenosi s or atresia. Because examination by echocardiography is often technically limited and catheterization is invasive, this study evaluated the diagnosti c accuracy of magnetic resonance imaging (MRI) as an alternate non-invasive tool. Thirteen patients (median age 28 years, range: 1-44 years) underwent both cardiac catheterization and MRI within a median of two months (range 0.1-8 months). Diagnoses included tetralogy of Fallot (TOF) with pulmonary atresia (n = 8), TOF with pulmonary stenosis (n = 2), single left ventricle with pulmonary stenosis (n = 2), and complex heterotaxy with pulmonary ste nosis (n = 1). The MRI sequences used in this study were ECG-gated spin ech o and gradient echo sequences acquired in multiple planes. Compared to cath eterization, MRI had 100% sensitivity and specificity for the diagnosis of main PA (n = 6) and branch PA (n = 13) hypoplasia or stenosis, as well as d iscontinuous (n = 4) or absent (n = 10) branch PAs. There was complete agre ement between catheterization and MRI identification of significant APCs (n = 18). Main PA atresia was noted by MRI in four patients but was not defin itively seen by catheterization in any. MRI but not catheterization precise ly defined the distance between discontinuous PAs and their relationship to other mediastinal structures. In conclusion, cardiac MRI is a reliable non -invasive imaging modality to define PA and APC anatomy in patients with co mplex pulmonary stenosis or atresia.