Rick J. van Tuijl¹, Ynte M. Ruigrok², Irene C. van der Schaaf¹, Lennart J. Geurts¹, Gabriël J. E. Rinkel², Birgitta K. Velthuis¹, and Jaco J. M. Zwanenburg^1
1Radiology, UMC Utrecht, Utrecht, Netherlands, ²Neurology, UMC Utrecht, Utrecht, Netherlands

We studied blood-flow pulsatility and arterial distensibility along the internal carotid artery (ICA) in cerebral small vessel disease (CSVD) patients and healthy controls using 7Tesla MRI. 4D-flow measurements (0.8 mm isotropic resolution), were analyzed in 17 patients with lacunar infarcts or deep intracerebral hemorrhage (CSVD) and 17 age and sex matched healthy controls. Pulsatility was significantly higher and arterial distensibility significantly lower in CSVD patients compared to controls. Velocity pulsatility was attenuated between the extracranial ICA and the circle of Willis in controls, but increased in CSVD. Higher calcification in CSVD patients correlated with reduced distensibility and increased velocity pulsatility. 

Yue Wu^1,2,3, Chengyue Sun⁴, Qingle Kong⁵, Zhixin Li^1,2,3, Dongbiao Sun^1,2,3, Chen Ling⁴, Jing An⁶, Rong Xue^1,2,3, Yan Zhuo^1,2,3, Yun Yuan⁴, and Zihao Zhang^1,2,3
1State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, ²The Innovation Center of Excellence on Brain Science, Chinese Academy of Sciences, Beijing, China, ³University of Chinese Academy of Sciences, Beijing, China, ⁴Department of Neurology, Peking University First Hospital, Beijing, China, ⁵MR Collaboration, Siemens Healthcare Ltd, Beijing, China, ⁶Siemens Shenzhen Magnetic Resonance Ltd, Shenzhen, China

In this study, we demonstrated a technique that could non-invasively quantify lenticulostriate artery (LSA) flow velocities in cerebral small vessel disease (CSVD). With phase-contrast magnetic resonance angiography (PC-MRA) at 7T, LSA blood flow velocities were detected in patients with CADASIL (a hereditary CSVD). LSA flow velocities decreased in patients compared with healthy individuals. We also found good associations between velocities and clinical characteristics among patients with CADASIL. These results suggest that PC-MRA at 7T is a valuable technique to assess small arterial dysfunction in patients with CSVD.

Hannes Dillinger¹, Eva Peper¹, Christian Guenthner¹, and Sebastian Kozerke^1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland

This work identifies mechanical resonances of the gradient coil system as a source of increased spatially linear and quadratic phase offsets. Mechanical resonance frequencies were identified by mobile phone audio recordings from inside the scanner room and compared to the gradient modulation transfer function. Results demonstrate that optimal TE reduces phase ramps by a factor of 15 and optimal TR removes the spatially quadratic phase offset.

Mariana Baginha da Lança Falcão¹, Giulia M. C. Rossi¹, Liliana Ma^2,3, John Heerfordt^1,4, Davide Piccini^1,4, Jérôme Yerly^1,5, Milan Prša⁶, Tobias Rutz⁷, Estelle Tenisch¹, Michael Markl^2,3, Matthias Stuber^1,5, and Christopher W. Roy^1
1Department of Radiology, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, ²Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States, ³Department of Biomedical Engineering, Northwestern University, Chicago, IL, United States, ⁴Advanced clinical imaging technology, Siemens Healthcare AG, Lausanne, Switzerland, ⁵Center for Biomedical Imaging (CIBM), Lausanne, Switzerland, ⁶Woman-Mother-Child Department, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, ⁷Service of Cardiology, Centre de resonance magnétique cardiaque (CRMC), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland

In this work, a free-running radial whole-heart flow sequence was acquired in five congenital heart disease patients and images were reconstructed using a) a previously developed 5D flow framework for respiratory and cardiac resolved images, and b) a novel framework for respiratory motion corrected and cardiac resolved 4D flow (fNAV). Image and flow differences were measured across a range of acceleration factors. We showed that the free-running acquisition, which is already undersampled, can be even further accelerated with less signal degradation if it is reconstructed with fNAV 4D flow, compared to using 5D flow.

Esteban Jorge Denecken-Campaña^1,2,3, Julio Sotelo^1,3,4, Cristobal Arrieta^1,3, Pablo Irarrazaval^1,2,3, Cristián Tejos^1,2,3, Marcelo E. Andia^1,3,5, and Sergio Uribe^1,3,5
1Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, ²Electrical Engineering Department, School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, ³ANID – Millennium Science Initiative Program – Millennium Nucleus for Cardiovascular Magnetic Resonance, Santiago, Chile, ⁴School of Biomedical Engineering, Universidad de Valparaíso, Valparaíso, Chile, ⁵Department of Radiology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile

Hemodynamic parameters from 4D flow datasets derived in the last years have shown promising diagnostic value in different cardiovascular pathologies. However, we know little about the behavior of these parameters when the 4D flow data is corrupted by respiratory motion. The purpose of this work is to perform a quantitative comparison between hemodynamic parameters computed from 4D flow Cardiac MRI with and without respiratory self-gating. We found significant variability of the hemodynamic parameters in the ascending aorta of healthy volunteers when comparing both methods. Hemodynamic parameters measured with self-gating acquisition showed statistically significant differences compared to those measured without self-gating.

Thara Nallamothu^1,2, Amanda L. DiCarlo¹, Daniel C. Lee³, Daniel Kim¹, Rishi Arora³, Michael Markl^1,2, Phillip Greenland⁴, Rod Passman³, and Mohammed S.M. Elbaz^1
1Radiology, Northwestern University, Chicago, IL, United States, ²Biomedical Engineering, Northwestern University, Chicago, IL, United States, ³Medicine (Cardiology), Northwestern University, Chicago, IL, United States, ⁴Preventative Medicine, Northwestern University, Chicago, IL, United States

4D Flow MRI studies have shown an association between atrial fibrillation (AF) with altered left atrial (LA) blood flow. Nevertheless, LA flow dynamics changes can be complex (vortex flow, jets, stagnations, etc.). Existing quantitative 4D flow metrics only characterize parts of the overall complex interacting LA flow dynamics. Here, we propose a novel stochastic 4D Flow signature technique to quantify the unique composition of normal and altered LA flow dynamics utilizing the entire 4D three-directional velocity-field from 4D Flow MRI. We demonstrate the excellent reproducibility and the feasibility of the technique in quantifying distinctly altered LA signatures in AF patients.

Xiaodan Zhao¹, Liwei Hu², Ru-San Tan^1,3, Ping Chai⁴, Marielle Fortier^3,5, Rong Zhen Ouyang², Shuo Zhang⁶, Wen Ruan¹, Ting Ting Low⁴, Shuang Leng¹, Jun-Mei Zhang^1,3, Bryant Jennifer¹, Lynette Teo⁴, Rob van der Geest⁷, Teng Hong Tan^3,5, James W. Yip⁴, Ju Le Tan^1,3, Yumin Zhong², and Liang Zhong^1,3
1National Heart Centre Singapore, Singapore, Singapore, ²Shanghai Children’s Medical Centre, Shanghai, China, ³Duke-NUS Medical School, Singapore, Singapore, ⁴National University Hospital Singapore, Singapore, Singapore, ⁵KK Women’s and Children’s Hospital, Singapore, Singapore, ⁶Philips Germany, Humburg, Germany, ⁷Leiden University Medical Center, Leiden, Netherlands

4D flow CMR enables qualitative and quantitative assessment of intra-cardiac flow. Kinetic energy (KE) and pathline-derived four flow components for left ventricular (LV) and right ventricular (RV) were analyzed and compared in repaired tetralogy of Fallot (rTOF) and age-matched controls. For RV, rTOF had increased peak systolic, systolic and peak E-wave KE normalized to end-diastolic volume while decreased efficiency index. RV direct flow decreased while RV residual volume increased from controls to rTOF with preserved RVEF (rTOFpEF) to rTOF with reduced RVEF. ROC analysis showed RV direct flow and efficiency index were sensitive markers to detect RV dysfunction in rTOFpEF.

Philip A Corrado¹, Gregory P Barton², Christopher J François³, Oliver Wieben¹, and Kara N Goss^2
1University of Wisconsin-Madison, Madison, WI, United States, ²University of Texas Southwestern, Dallas, TX, United States, ³Mayo Clinic, Rochester, MN, United States

We used 4D flow MRI before and during acute pharmacological intervention to reduce either afterload or heart rate in young adults born very to extremely premature, finding improved overall cardiac function and shifted intraventricular flow in the RV towards direct flow after RV afterload reduction with sildenafil. We interpret these findings to mean that intrinsic morphologic differences as well as increased RV afterload are stronger drivers of cardiac dysfunction in the preterm heart than decreased filling time. This study design may serve as a blueprint for future studies investigating the effects of acute hemodynamic pharmacological interventions with 4D flow MRI.

Yu-Ru Yang¹, Meng-Chu Chang¹, Ming-Ting Wu², Ken-Pen Weng³, and Hsu-Hsia Peng^1
1Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, ²Radiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ³Pediatrics, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan

We aim to evaluate aortic kinetic energy (KE) and viscous energy loss (EL) in repaired tetralogy of Fallot (rTOF) patients with different degrees of aortic regurgitation fraction (RF). The rTOF1 group (RF<2%) demonstrated decreased systolic KE in arch and descending aorta, suggesting the mild altered aortic flow. The rTOF2 group (RF≧2%) presented significantly elevated RF in arch and descending aorta, increased systolic KE from distal ascending aorta to proximal descending aorta, and decreased systolic EL in ascending aorta and distal arch. In conclusion, the systolic KE may provide earlier evidence of abnormal aortic flow before serious aortic regurgitation.

Pim van Ooij¹, Mitzi van Andel², Lukas M. Gottwald¹, Aart J Nederveen¹, and Maarten Groenink^1
1Radiology & Nuclear Medicine, Amsterdam University Medical Centers, location AMC, Amsterdam, Netherlands, ²Cardiology, Amsterdam University Medical Centers, location AMC, Amsterdam, Netherlands

In this study we use 4D flow MRI techniques to investigate abnormal magnitude and direction of blood flow velocity and wall shear stress in patients with Marfan syndrome, a congenital disease that may cause aortic dissection. We found that patients that underwent aortic root repair have significantly more abnormal hemodynamics and that abnormally elevated hemodynamics were associated with blood pressure chracteristics. Abnormally directed hemodynamics were not associated with any patient characteristics, but showed a distinct regional increase at the inner proximal descending aorta,  awell-know predilection site for aortic dissection in Marfan patients.