Daniel Giese^1,2, Bertram Wilm^2,3, Julia Busch², David Maintz¹, Christoph Barmet^2,3, Klaas Pruessmann², and Sebastian Kozerke^2
1Radiology, University Hospital Cologne, Cologne, Germany, ²Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, ³Skope Magnetic Resonance Technologies, Zurich, Switzerland

Concurrent magnetic field monitoring is used to analyze and correct for eddy-current related background phase offsets in phase-contrast MRI. It is demonstrated that 3rd order correction results in residual background offsets of less than 0.6 cm/s. Using simultaneous acquisition of field monitoring and imaging data, temperature dependent changes in background phase offsets are inherently captured and corrected for.

Zixin Deng^1,2, Yang Qi², Xiaoming Bi³, Zhaoyang Fan², and Debiao Li^1,2
1Bioengineering, University of California, Los Angeles, Los Angeles, California, United States, ²Biomedical Imaging Research Institute (BIRI), Cedars-Sinai Medical Center, Los Angeles, California, United States, ³R&D, Siemens Healthcare, Los Angeles, California, United States

Fractional Flow Reserve (FFR) invasively evaluates the functional severity of an intermediate stenosis by measuring the stenotic pressure drop via catheterization. Noninvasive pressure measurements using PC-MRI and Navier-Stokes equations have been shown in the aorta, carotid and renal arteries. In this study, the feasibility and reproducibility of PC-MRI and noninvasive pressure calculations were evaluated in the coronary arteries to establish the robustness of noninvasive FFR measurement using MRI. Excellent correlations were observed in the through-plane and slightly lower in the in-plane velocities between the repeated acquisitions. The noninvasive pressure values in healthy subjects were near zero, as expected.

Joseph Y Cheng^1,2, Marcus T Alley², Tao Zhang^1,2, Peng Lai³, Jonathan I Tamir⁴, Martin Uecker⁴, John M Pauly¹, Michael Lustig⁴, and Shreyas S Vasanawala^2
1Electrical Engineering, Stanford University, Stanford, CA, United States, ²Radiology, Stanford University, Stanford, CA, United States, ³Global Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States, ⁴Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, United States

Time-resolved phase contrast MRI (4D flow) can quantify cardiac function and flow. The technique may even permit complex anatomical assessment, thus comprising a comprehensive exam in a single scan. Unfortunately, artifacts from respiratory motion compromise this ability. Therefore, we developed a simple method to measure motion using readily available navigation information from the flow encoding gradients. We incorporated and modified a variable-density sampling and radial view-ordering scheme to facilitate motion correction and compressed sensing methods. Lastly, we integrated soft-gating to the compressed sensing and parallel imaging reconstruction. These motion-compensation approaches help improve the reliability and resolution of 4D flow imaging.

Jehill D Parikh¹, Kieren G Hollingsworth¹, Andrew M Blamire¹, and Guy MacGowan^2
1Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom, ²Cardiology, Freeman Hospital, Newcastle Upon Tyne, Tyne and Wear, United Kingdom

Aorta rapidly expands during a ventricular contraction accommodating the majority (50% or more) of the stroke volume. Aortic stiffness increases with age, and is regarded as an independent risk factor in the development of cardiovascular disease. Additionally, normal ageing is characterized by age-related diastolic dysfunction, altered systolic strains and impaired myocardial energetics. In this study we explore associations between age-related increase in aortic stiffness and cardiac energetics and left ventricular function. Such associations may provide important insights into how normal ageing affects the heart, which may allow development of potential treatments to attenuate this process.

Julio Sotelo^1,2, Jesus Urbina^1,3, Israel Valverde^4,5, Cristian Tejos¹, Pablo Irarrazaval¹, Daniel E. Hurtado^2,6, and Sergio Uribe^1,3
1Biomedical Imaging Center, Electrical Engineering Department, Pontificia Universidad Catolica de Chile, Santiago, RM, Chile, ²Structural and Geotechnical Engineering Departement, Pontificia Universidad Catolica de Chile, Santiago, RM, Chile, ³Radiology Department, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile, ⁴Pediatric Cardiology Unit, Hospital Virgen del Rocio, Seville, Spain, ⁵Cardiovascular Pathology Unit, Institute of Biomedicine of Seville (IBIS), Hospital Virgen del Rocio, Seville, Spain, ⁶Biomedical Engineering Group, Pontificia Universidad Catolica de Chile, Santiago, Chile

Several methods have been proposed to analyze hemodynamic parameters from 4D flow data, including vorticity and helicity. However the analysis is usually qualitative and performed in reformatted 2D planes. In this work we propose a novel method that integrates advanced image processing strategies and computational techniques based on finite element interpolations to obtain a 3D quantitative map of vorticity, helicity density and relativity helicity density derived from 4D flow data sets obtained from volunteers and patients.

Pim van Ooij¹, Wouter V Potters¹, Jeremy D Collins², James C Carr², S Chris Malaisrie³, Patrick M McCarthy⁴, Michael Markl², and Alex J Barker^2
1Radiology, Academic Medical Center, Amsterdam, Netherlands, ²Radiology, Northwestern University, Chicago, IL, United States, ³Medicine-Cardiology, Northwestern University, Chicago, IL, United States, ⁴Division of Cardiac Surgery, Northwestern University, Chicago, IL, United States

Recently a technique was developed to visualize patient-specific abnormal aortic velocity and wall shear stress (WSS) for guidance in tissue resection surgery for BAV disease. In this study, the reproducibility of the technique is investigated by comparing abnormal velocity and WSS of baseline and follow-up (separated by appr. a year) 4D flow MRI in 24 BAV patients and 15 tricuspid aortic valves and aortic dilatation (TAV+D). No significant differences were found in aortic diameter, peak velocity or abnormal velocity and WSS. Therefore, the technique is stable.

Julio Garcia¹, Alex J Barker¹, Ian Murphy¹, Kelly B Jarvis¹, Alex L Powell¹, Susanne Schnell¹, Jeremy Collins¹, James Carr¹, S Chris Malaisrie², and Michael Markl^1,3
1Radiology, Northwestern University, Chicago, Illinois, United States, ²Division of Cardiothoracic Surgery, Northwestern University, Chicago, Illinois, United States, ³Biomedical Engineering, Northwestern University, Evanston, Illinois, United States

Aortic diameter and peak velocity are important metrics for the characterization of aortic disease. However, these parameters are typically evaluated at selected locations along the aorta and are thus subject to observer variability and may miss the true maximum aortic diameter or velocity. The purpose of this study was to apply volumetric 4D flow MRI for the simultaneous assessment of aorta morphometry and flow parameters along the entire volume of the thoracic aorta in patients with aortic dilation.

Peter Bannas^1,2, Alejandro Roldán-Alzate¹, Kevin M Johnson³, Michael A Woods¹, Utaroh Motosugi¹, Oliver Wieben³, Scott B Reeder^1,3, and Harald Kramer^1,4
1Radiology, University of Wisconsin-Madison, Madison, WI, United States, ²Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Hamburg, Germany, ³Medical Physics, University of Wisconsin-Madison, WI, United States, ⁴Radiology, Ludwig-Maximilians-University Hospital, Munich, Bavaria, Germany

Transjugular intrahepatic portosystemic shunt (TIPS) is non-surgical method of portal decompression to treat major complications of portal hypertension. Currently, the combination of Doppler ultrasound and invasive portosystemic pressure measurements are applied to monitor patients before and after TIPS placement. An alternative operator-independent and non-invasive technique would be highly desirable. In this study we demonstrate the feasibility of 4D-flow MRI for qualitative and quantitative analyses of hepatic blood flow before and then 2 and 12 weeks after TIPS placement. 4D flow MRI is feasible for longitudinal hemodynamic monitoring of the blood flow in the portal vein and the TIPS stent.

Jeremy Douglas Collins¹, Jad Bou Ayache², Edouard Semaan³, Riad Salem⁴, James Christian Carr³, Michael Markl³, and Zoran Stankovic^5
1Radiology, Northwestern University, Chicago, IL, United States, ²Radiology, Icahn School of Medicine at Mount Sinai, New York, United States, ³Northwestern University, Illinois, United States, ⁴Radiology, Northwestern University, Illinois, United States, ⁵Radiology, University Hospital, Freiberg, Germany

There is a clinical need for a non-invasive diagnostic test to assess spleen function. Quantitative splenic hemodynamics, assessed using non-contrast 4D flow MRI, demonstrate differences between patients with severe and mild thrombocytopenia and may be useful to distinguish patients with hypersplenism associated thrombocytopenia from those with thrombopoetin deficiency.

Jing Liu¹, Farshid Faraji¹, Sarah Kefayati¹, Henrik Haraldsson¹, and David Saloner^1,2
1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, ²Radiology Service, VA Medical Center, San Francisco, CA, United States

An effective k-space undersampling scheme for 3D Cartesian acquisition combined with compressed sensing and parallel imaging has successfully been implemented and applied to intracranial 4D flow MRI. Our preliminary results demonstrated that the proposed approach achieved high image quality and accurate velocity imaging with largely accelerated acquisition (R=7).