Which MRI sequence provides the most accurate estimate of branch pulmonary artery size in children with single ventricle?

Abstract

Background Accurate evaluation of branch pulmonary artery size in children with single ventricle is important for surgical planning and has prognostic implications after Fontan surgery. Various cardiac MRI sequences are employed to evaluate these sometimes hypoplastic pulmonary arteries, which increases imaging time in anesthetised children. The aim of this study was to evaluate which MRI sequence(s) correlate with angiography measure- ments of pulmonary artery size made at cardiac cathe- terization in children with single ventricle. Methods regression with 95% confidence intervals were used to compare MRI with the gold standard catheterization angiography measurements (p<0.05). Results For the RPA, all MRA measured dimensions correlated well with catheterization angiography (axial r=0.81, cor- onal r=0.89, cross-sectional area r=0.81, p<0.0001), with axial dark blood (r=0.65, p=0.02) and cine diameters (r=0.67, p=0.03) showing modest correlations. In con- trast, LPA through plane PC area correlated best (r=0.73, p=0.02), with modest correlations for axial dark blood (r=0.54, p=0.04), MRA axial diameter (r=0.55, p=0.02), and MRA cross-sectional area (r=0.48, p=0.05). Conclusions In children with single ventricle, MPR contrast enhanced MRA measurements showed the best correlate of RPA size compared to catheterization angiography. However, LPA cross-sectional area from PC flow mea- surements, and not MRA, were the best correlate of LPA measurements. Selection of the most appropriate sequence will provide a more accurate pre-operative evaluation of pulmonary artery size to aid the surgical strategy in this population. Knowledge of this will help tailor protocols to study pulmonary artery size in this population and imaging time may be shortened with this in mind. Funding none.