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1054 Noninvasive Qp/Qs ratio measurement with phase-contrast cine MRI in patients with atrial septal defect: comparison with heart catheterization


Blood flow can be quantified noninvasively by phase-contrast cine MRI (PC-MRI) in adults. Little is known about the accuracy of this measurement in patients with known atrial septal defect.


Aim of the study was to compare the results of PC-Mri with heart catheterization


In 25 patients with a type-II atrial septal defect, blood flow rate in the great vessels was determined by 1 Tesla PC-MRI and the ratio of pulmonary to aortic flow (Qp/Qs) was compared with Qp/Qs by oximetry requiring heart catheterization, performed before of an attempt of percutaneous closure of the defect.


The interval between measurements was 11 ± 18 days (range 1–78 days). Mean Qp was 9.2 ± 3.3 l/min with PC-MRI, and 8.6 ± 4 l/min with catheterization (p = 0.57). Mean Qs was 4.8 ± 1.6 l/min with PC-MRI, and 4.5 ± 1.3 l/min with catheterization (p = 0.46). Qp/Qs ratio was 1.99 ± 0.72 with PC-MRI, and 1.96 ± 0.96 with catheterization (p = 0.92).

The correlation analysis showed a good overlap between measurements (Qp: r = 0.65, p = 0.0004; Qs: r = 0.64, p = 0.0005; Qp/Qs ratio: r = 0.68, p = 0.0002), also confirmed by regression analysis (R2 = 0.42, p < 0.001 for Qp; R2 = 0.41, p = 0.001 for QS; R2 = 0.46, p < 0.001 for Qp/Qs ratio), and by the Bland-Altman statistical analysis for method comparison (see Figure 1). The interobserver variability was low.


Figure 1


Determination of Qp/Qs ratio by PC-MRI is quick, safe, and reliable compared with oximetry. This noninvasive method could be used to quantify the interatrial shunt in patients with known atrial septal type-II defect, in order to demonstrate hemodinamic importance of the defect, and to reduce the need for time-consuming diagnostic heart catheterization.

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Correspondence to Amedeo Chiribiri.

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Open Access This article is published under license to BioMed Central Ltd. This is an Open Access article is distributed under the terms of the Creative Commons Attribution 2.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Chiribiri, A., Rizzo, L., Marocco, M.C. et al. 1054 Noninvasive Qp/Qs ratio measurement with phase-contrast cine MRI in patients with atrial septal defect: comparison with heart catheterization. J Cardiovasc Magn Reson 10, A179 (2008).

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  • Public Health
  • Blood Flow
  • Regression Analysis
  • Correlation Analysis
  • Method Comparison