Lisa Leroi¹, Sebastian Flassbeck^2,3, and Sebastian Schmitter^1,2
1Physikalisch-Technische Bundesanstalt Berlin (PTB), Braunschweig and Berlin, Germany, ²Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, ³Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany

The simultaneous quantification of blood velocity and tissue relaxation times could be a valuable tool for clinicians, especially in the carotid arteries, where atheroma plaques could occur. This can be achieved using the recently presented Flow-MRF technique that relies on the acquisition of randomly distributed gradients m₁ momentum using a FISP MRF-sequence, with varying flip angle and fixed TR. In this work, Flow-MRF is extended to a time-resolved 3D acquisition and successfully applied in-vivo to the carotid bifurcation at 3T. T₁, T₂ and 3D time-resolved flow maps are recovered in a 3D slab.

Lukas M. Gottwald¹, Joao Tourais^2,3, Eva S. Peper¹, Jouke Smink², Bram F. Coolen⁴, Gustav J. Strijkers⁴, Pim van Ooij¹, and Aart J. Nederveen^1
1Radiology and Nuclear Medicine, Amsterdam UMC, Amsterdam, Netherlands, ²MR R&D – Clinical Science, Philips Healthcare, Best, Netherlands, ³Department of Biomedical Engineering, University of Technology, Eindhoven, Netherlands, ⁴Biomedical Engineering and Physics, Amsterdam UMC, Amsterdam, Netherlands

This study aimed to compare the performance of the novel camera-based respiratory navigation sensor (VitalEye) in retrospective respiratory binned Cartesian 4D flow MRI to conventional liver navigator and self-gating. Analyzed were the cross-correlation of the respiratory signals, peak flow rate error compared to 2D flow and the image quality in terms of edge sharpness of the liver/diaphragm border and signal-to-noise ratio. The novel camera-based respiratory navigation sensor VitalEye performed as good as conventional liver navigator and self-gating. Respiratory signal, flow rate error, and image quality showed no significant difference, but VitalEye has the advantage of a 10-times higher sampling frequency.

Aaron Pruitt¹, Peter Speier², Chong Chen¹, Yingmin Liu³, Ning Jin⁴, Orlando Simonetti⁵, and Rizwan Ahmad^1
1Biomedical Engineering, The Ohio State University, Columbus, OH, United States, ²Siemens Healthcare GmbH, Erlangen, Germany, ³Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States, ⁴Siemens Medical Solutions USA, Inc., Columbus, OH, United States, ⁵Cardiovascular Medicine and Radiology, The Ohio State University, Columbus, OH, United States

Pilot Tone has recently been proposed as a novel approach towards physiological signal monitoring. Unlike self-gating, often relied upon by free-running, respiratory-resolved imaging sequences, Pilot Tone is generalizable to a multitude of imaging techniques without requiring additional pulse sequence modification or specialized k-space sampling. In this work, we combine Pilot Tone with our previously described highly accelerated and fully self-gated whole-heart 4D flow framework to reconstruct respiratory-resolved 4D flow images in three healthy subjects. We compare Pilot Tone and self-gating derived respiratory binning and demonstrate good agreement in aortic and pulmonary artery flow quantification between the two methods.

Rajiv Ramasawmy¹, Daniel Herzka¹, Robert Lederman¹, and Adrienne Campbell-Washburn^1
1National Heart, Lung & Blood Institute, National Institutes of Health, Bethesda, MD, United States

A balanced SSFP (bSSFP) phase-contrast using a spiral readout was implemented for quantitative flow measurements at 0.55T. bSSFP flow is challenging at 1.5T and 3T due to off-resonance. However, at 0.55T, this sequence exploits the improved field inhomogeneity for a long readout (TR = 7.2ms) bSSFP spiral acquisition. This sequence provided improved signal-to-noise ratio (SNR) normalized by voxel, especially during diastole (Cartesian gradient echo SNR/voxel = 3.6, spiral bSSFP SNR/voxel = 9.4), to produce quality flow measurements at 0.55T.

Gilles Soulat¹, Michael Scott¹, Ashitha Pathrose¹, Kelly Jarvis¹, Haben Berhane², Bradley Allen¹, Ryan Avery¹, Cynthia Rigsby², and Michael Markl^3
1Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States, ²Department of Medical Imaging, Ann & Robert H. Lurie Children’s Hospital of Chicago,, Chicago, IL, United States, ³Department of Radiology, Feinberg School of Medicine, and Department of Biomedical Engineering, McCormick School of Engineering; Northwestern University, Chicago, IL, United States

Bicuspid aortic valve (BAV) patients with history of aortic coarctation are considered higher risk for aortic complications. We evaluated 4D flow aortic metrics in 15 BAV adults with coarctation repair (mean age 35y) retrospectively reviewed at baseline and follow-up (3.98y [2.10 to 4.96y ]). Areas of higher wall shear stress were mainly located in the arch, and 4D flow metrics remained stable at follow-up. Aortic growth was slow, with a significant increase in the anterior arch (0.25mm/y) and diaphragmatic aorta (0.27mm/y). At baseline, peak velocity at the coarctation repair site was inversely correlated to mid arch and diaphragmatic aortic growth.  

Michael C Langham¹, Felix W Wehrli¹, Alessandra S Caporale¹, and Nadav Schwartz^2
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²Maternal Fetal Medicine, University of Pennsylvania, Philadelphia, PA, United States

Significant maternal cardiovascular adaptations take place during pregnancy. One such alteration is a decrease in peripheral vascular resistance to accommodate an increase in cardiac output. In this pilot study, we aimed to evaluate changes in vascular reactivity during normal pregnancy by quantifying MRI surrogate markers of endothelial function. A novel quantitative MRI protocol was performed on 14 healthy pregnant women to evaluate peripheral micro- and macrovascular reactivity and central arterial stiffness. Preliminary results indicate attenuated peripheral vascular reactivity consistent with previous studies of brachial artery reactivity using ultrasound in pregnant women.

Ethan M I Johnson¹, J. Alex Heller², Flori Garcia Vicente², Mozziyar Etemadi^1,2, Alex Barker³, and Michael Markl^1,4
1Biomedical Engineering, Northwestern University, Evanston, IL, United States, ²Anesthesiology, Northwestern University, Chicago, IL, United States, ³Radiology and Biomedical Engineering, University of Colorado, Anschutz Medical Campus, Aurora, CO, United States, ⁴Radiology, Northwestern, Chicago, IL, United States

Aortic valve diseases (AVD) require regular monitoring of aortic size and blood speeds. MRI can quantify morphology and flow parameters, such as velocity and wall shear stress, with high accuracy and reproducibility, especially as compared to echocardiography.  However, the value proposition may be low for performing repeated MRI if there has been no change in disease state.  A quick, inexpensive and easy to use test that identifies potential need for MR imaging could significantly raise the cost-effectiveness of using MRI for monitoring AVD. Here we show high potential screening efficacy of using seismocardiography to select AVD patients needing MRI examination.

Carmen PS Blanken¹, Eva S Peper¹, Lukas M Gottwald¹, Bram F Coolen², Gustav J Strijkers², R Nils Planken¹, Aart J Nederveen¹, and Pim van Ooij^1
1Radiology and Nuclear Medicine, Amsterdam UMC, Amsterdam, Netherlands, ²Biomedical Engineering, Amsterdam UMC, Amsterdam, Netherlands

Coronary flow reserve (CFR) is a clinical test that interrogates the function of the entire coronary vasculature, indicating the presence of coronary stenoses, microvascular disease or both in patients with ischemic heart disease. We used 15 times accelerated 4D flow MRI with compressed sensing reconstruction at an isotropic spatial resolution of 1.0 mm to measure diastolic flow in the left coronary artery of six healthy subjects. Mean diastolic flow was 1.15±0.18 ml/s with a mean scan-rescan difference of 0.06 ml/s. 4D flow MRI-based diastolic flow quantification in the LCA is feasible and could enable non-invasive CFR measurement.

Shi-Ying Ke¹, Meng-Chu Chang¹, Ming-Ting Wu², Ken-Pen Weng^3,4, and Hsu-Hsia Peng^1
1Department of Biomedical Engineering and Environmental Sciences, National TsingHua University, Hsinchu, Taiwan, ²Department of Radiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ³Department of Pediatrics, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ⁴Department of Pediatrics, National Yang-Ming University, Taipei, Taiwan

We aimed to investigate the interaction between myocardial kinetic energy (KE_myo) and intraventricular KE (KE_ven) in left- and right-ventricle (LV, RV) for repaired tetralogy of Fallot (rTOF) patients. The rTOF group displayed higher systolic RV KE_ven, earlier LV myocardial diastolic time-to-peak (TTP_myo), earlier RV TTP_myo in both systole and diastole, earlier LV TTP_ven in both systole and diastole, and earlier RV TTP_ven in systole. In conclusion, from an insight of energy conversion, rTOF patients demonstrated undermined interaction between LV KE_myo and KE_ven  in an early stage. The dilated RV potentially have impacts on the RV KE_ven in rTOF patients.

Alessandra Caporale¹, Shampa Chatterjee², Michael C Langham¹, Wensheng Guo³, Frank Leone⁴, Andrew Strasser⁵, and Felix W Wehrli^1
1Radiology, Laboratory for Structural, Physiologic and Functional Imaging, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States, ²Physiology, Institute for Environmental Medicine, Perelman School of Medicine, Philadelphia, PA, United States, ³Biostatistics and Epidemiology, Perelman School of Medicine, Philadelphia, PA, United States, ⁴University of Pennsylvania Medical Center, Pulmonary, Allergy & Critical Care Division, Philadelphia, PA, United States, ⁵Psychiatry, Center for Interdisciplinary Research on Nicotine Addiction, Philadelphia, PA, United States

The vascular effects of e-cigarette use were investigated in young adults (19-35 years). Blood draws and 3T-MRI data were collected from seven e-cigarette users, seven smokers, thirty nonsmokers, the latter replicating the measurements after one nicotine-free e-cigarette vaping session. MRI-protocol measured peripheral vascular reactivity in response to cuff-induced ischemia, quantifying femoral artery luminal flow mediated dilation (FMD_L), blood flow velocity, venous saturation (SvO₂). FMD_L decreased by 33% acutely after vaping, consistent with 20% NOx reduction and elevated inflammation (C-reactive protein increased by 95%). Reactive hyperemia was blunted as a chronic effect of both smoking and vaping, paired with anomalous biomarkers.