Albert Hsiao MD, PhD, Presenter: Founder, Morpheus Imaging, Inc Consultant, Morpheus Imaging, Inc

Ufra Yousaf, Abstract Co-Author: Nothing to Disclose

Marcus T. Alley PhD, Abstract Co-Author: Nothing to Disclose

Frandics Pak Chan MD, PhD, Abstract Co-Author: Nothing to Disclose

Beverley Mansfield Newman MD, MBBCh, Abstract Co-Author: Nothing to Disclose

Shreyas Shreenivas Vasanawala MD, PhD, Abstract Co-Author: Research collaboration, General Electric Company Stockholder, Morpheus Imaging, Inc

Cardiac MRI is routinely performed for morphologic characterization and quantification of pulmonary-to-systemic shunting in patients with anomalous pulmonary veins, but can be labor-intensive to perform. Highly-accelerated, compressed-sensing parallel-imaging 4D phase-contrast MRI (4D-PC) is an emerging MRI technique, but has lacked software for analysis and quantification of complex pulmonary venous flow. Furthermore, it is yet unclear whether pulmonary venous and shunt flow can be reliably measured from 4D-PC data.

With IRB approval and HIPAA-compliance, we retrospectively identified all patients with anomalous pulmonary veins who underwent quantitative cardiac MRI with 4D-PC between April, 2011 and October, 2013. 14 exams were identified (9 male, 5 female). 6 were performed at 1.5T and 8 at 3T after single-dose gadofosveset intravenous contrast. Algorithms for real-time interactive streamline visualization were integrated into in-house software. Blood flow was quantified at the outflow valves, branch pulmonary arteries, cavae, pulmonary veins, and any ASD or VSD. Pulmonary veins were mapped to their receiving atrial chamber with streamlines. The intraobserver, interobserver, and internal consistency of flow measurements were then evaluated with Pearson correlation and Bland-Altman analysis.

Mean acquisition time was shorter at 3T (5 min) than at 1.5T (9 min), due to higher acceleration factors possible at 3T (6-8 fold versus 4-fold). Among triplicate measurements, the coefficient of variation was smallest at the aortic and pulmonary valves (4-5%), moderate in the branch pulmonary arteries (18%) and greatest at the IVC (27%). These largely agreed with single measurements from a second observer (ρ =0.891-0.999), depending on location and complexity of anatomy. After pulmonary veins were assigned to their receiving atrial chambers, direct measurements of shunt volume from anomalous veins and intracardiac shunts matched indirect estimates from the outflow valves (ρ=0.966).

With streamline venous mapping, 4D-PC MRI can provide detailed and quantitatively consistent delineation of anomalous pulmonary veins and shunt flow.

By providing a comprehensive quantitative view of extracardiac and intracardiac flow, highly-accelerated 4D-PC may be a time-efficient alternative to conventional planar MRI for patients with complex venous flow.

Hsiao, A, Yousaf, U, Alley, M, Chan, F, Newman, B, Vasanawala, S, Quantification and Mapping of Anomalous Pulmonary Venous Flow with Highly-accelerated 4D Phase-contrast MRI and Real-time Interactive Streamline Rendering.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14019105.html