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Published on: January 7, 2021
4D Flow MRI Quantification of Congenital Shunts: Comparison to Invasive Catheterization.
Michael J Horowitz1, Daniel F Kupsky1, Howaida G El-Said1
1Department of Radiology, UC San Diego Medical Center, 200 W Arbor Dr, San Diego, CA 92103 (M.J.H., S.J.K., A.H.); Division of Cardiology (D.F.K., L.A.) and Department of Pediatrics, Division of Cardiology (H.G.E.), UC San Diego, La Jolla, Calif; and Division of Cardiology, UC Los Angeles Health, Los Angeles, Calif (D.F.K.).
Four-dimensional flow MRI accurately estimates shunt fraction in patients with heart shunts, showing strong correlation with invasive cardiac catheterization. This non-invasive imaging technique offers a reliable alternative for assessing pulmonary-to-systemic flow ratios.
Area of Science:
- Cardiovascular Imaging
- Medical Physics
- Diagnostic Radiology
Background:
- Intracardiac and extracardiac shunts require accurate shunt fraction estimation for management.
- Invasive right heart catheterization is the traditional method for quantifying shunt fraction.
- Non-invasive imaging modalities are sought to provide comparable diagnostic accuracy.
Purpose of the Study:
- To compare the accuracy of four-dimensional (4D) flow MRI with invasive right heart catheterization in estimating shunt fraction (pulmonary-to-systemic flow ratio, Qp/Qs).
- To evaluate secondary parameters including right ventricular-to-left ventricular stroke volume ratio (RVSV/LVSV) and cardiac output.
- To assess the feasibility of 4D flow MRI as a non-invasive alternative for shunt quantification.
Main Methods:
- Retrospective analysis of 33 patients who underwent both 4D flow MRI and right heart catheterization between August 2015 and November 2018.
- Primary endpoint: comparison of Qp/Qs measurements between 4D flow MRI and catheterization.
- Secondary endpoints: comparison of RVSV/LVSV and cardiac output (Qp, Qs) between the two methods; statistical analysis using Pearson correlation and Bland-Altman plots.
Main Results:
- 4D flow MRI demonstrated a strong correlation with catheterization for Qp/Qs estimation (r = 0.938) with no significant bias.
- RVSV/LVSV showed strong correlation with Qp/Qs derived from both 4D flow MRI (r = 0.852) and catheterization (r = 0.842).
- Moderate correlations were observed for cardiac output measurements (Qp: r = 0.673, Qs: r = 0.750) between 4D flow MRI and catheterization.
Conclusions:
- 4D flow MRI provides accurate and comparable shunt fraction measurements to invasive right heart catheterization.
- 4D flow MRI is a promising non-invasive tool for evaluating intracardiac and extracardiac shunts.
- The findings support the potential clinical utility of 4D flow MRI in cardiovascular diagnostics.
