title: Quantification of left-to-right shunting in adult congenital heart disease: phase-contrast cine MRI compared with invasive oximetry.
abstract: Atrial septum defects (ASDs), ventricular septum defects (VSDs) and patent ductus arteriosus (PDA) are the most common adult congenital heart defects. The degree of left-to-right shunting as assessed by the ratio of flow in the pulmonary (Qp) and systemic circulation (Qs) is crucial in the management of these conditions. This study compared phase-contrast cine magnetic resonance imaging (PC-MRI), a non-invasive imaging technique, with invasive oximetry for the measurement of shunt volumes during cardiac catheterisation in adults with left-to-right shunting. Both invasive oximetry and shunt quantification by PC-MRI (1.5 T scanner; Sonata, Siemens Medical Solutions) were performed on 21 patients with left-to-right shunting (14 ASD, 5 VSD, 2 PDA) and data on Qp/Qs ratios and left-to-right shunt fraction compared. Mean Qp/Qs ratios assessed by PC-MRI and oximetry were 2.10+/-0.76 and 1.96+/-0.77, respectively (p = 0.37). Mean shunt fraction was 46.3+/-19.6% when calculated by PC-MRI and 42.3+/-20.1% when obtained by oximetry (p = 0.12). There was a strong correlation of Qp/Qs ratios and shunt fraction between both methods (r = 0.61, p < 0.01 and r = 0.84, p < 0.0001, respectively). The two methods had a good agreement according to Bland and Altman plots with a small but non-significant overestimation of Qp/Qs-ratios and shunt fraction by PC-MRI. On receiver operating characteristic analysis, the sensitivity and specificity of PC-MRI to detect an oximetry-derived Qp/Qs ratio of > or =1.5:1 were 93% and 100% at a PC-MRI threshold of a Qp/Qs ratio > or =1.75:1 (area under curve (AUC) = 0.99). Quantification of left-to-right shunting can be performed reliably and accurately by PC-MRI and the data obtained by this method correlate closely to those from invasive oximetry.
authors.affiliation: Klinik und Poliklinik für Innere Medizin II, Universitätsklinikum Regensburg, Germany. kurt.debl@klinik.uni-regensburg.de
authors.forename: K
authors.initials: K
authors.lastname: Debl
authors.forename: B
authors.initials: B
authors.lastname: Djavidani
authors.forename: S
authors.initials: S
authors.lastname: Buchner
authors.forename: N
authors.initials: N
authors.lastname: Heinicke
authors.forename: F
authors.initials: F
authors.lastname: Poschenrieder
authors.forename: S
authors.initials: S
authors.lastname: Feuerbach
authors.forename: G
authors.initials: G
authors.lastname: Riegger
authors.forename: A
authors.initials: A
authors.lastname: Luchner
mesh_terms: D000328:Adult; D000368:Aged; D001011:Aorta / Q000503:physiopathology; D006328:Cardiac Catheterization; D003326:Coronary Circulation / Q000502:physiology; D004374:Ductus Arteriosus, Patent / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006344:Heart Septal Defects, Atrial / Q000175:diagnosis / Q000503:physiopathology*; D006345:Heart Septal Defects, Ventricular / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010092:Oximetry / Q000379:methods*; D011651:Pulmonary Artery / Q000503:physiopathology; D011652:Pulmonary Circulation / Q000502:physiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity