Ryuichi Mori¹, Hideki Ota², Simon TUPIN³, Tomoyoshi Kimura¹, Hironobu Sasaki¹, Tatsuo Nagasaka¹, Takashi Nishina⁴, Sho Tanaka⁴, Yoshiaki Morita², Yoshimori kassai⁴, and Kei Takase^2
1Department of Radiology, Tohoku University Hospital, Sendai, Japan, ²Diagnostic Radiology, Tohoku University Hospital, Sendai, Japan, ³Institute of Fluid Science, Tohoku University, Sendai, Japan, ⁴Canon Medical Systems corp., Tochigi, Japan

Visceral arterial diseases should be evaluated before and after endovascular interventions. We compared ultrashort TE (UTE) and steady-state free precession (SSFP) time-SLIP MRAs regarding their signal decay in pulsatile flow phantoms reflecting stenosis, aneurysm, and metallic stents. In all phantom models, UTE time-SLIP MRA provided superior visualization of target lumens to SSFP time-SLIP MRA. UTE time-SLIP MRA demonstrated minimal signal decay except for in-stent lumen of a stainless-steel stent. Our results indicated robustness of UTE time-SLIP MRA for intra-voxel spin dephasing caused by accelerated flow at the stenosis, turbulent flow in the aneurysm and susceptibility effects from metallic devices. 

Masami Yoneyama¹, Shuo Zhang², Yasuhiro Goto³, Michinobu Nagao⁴, Kayoko Abe⁴, Osamu Togao⁵, Isao Shiina³, Kazuo Kodaira³, Yutaka Hamatani³, and Marc Van Cauteren^6
1Philips Japan, Tokyo, Japan, ²Philips Healthcare, Hamburg, Germany, ³Department of Radiological Services,, Tokyo Women’s Medical University, Tokyo, Japan, ⁴Department of Diagnostic Imaging and Nuclear Medicine, Tokyo Women’s Medical University, Tokyo, Japan, ⁵Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan, ⁶Philips Healthcare, Best, Netherlands

Direct visualization of the plaques and vessel wall lesions in addition to luminal changes is of clinical importance for management of patients with atherosclerotic disease. In this work, the recently proposed REACT (Relaxation-Enhanced Angiography without Contrast and Triggering) technique was further developed and particularly optimized with Multiple Delays (REACT-MD) to simultaneously provide non-contrast-enhanced MR angiogram and MPRAGE (magnetization prepared rapid gradient echo) type images with uniform background tissue suppression over a large field of view. Initial results in patients showed great promise in detection of luminal changes and plaques for assessment of systemic atherosclerosis in one single scan.

Christopher W. Roy¹, John Heerfordt^1,2, Davide Piccini^1,2, Juerg Schwitter³, and Matthias Stuber^1,4
1Radiology, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, ²Advanced Clinical Imaging Technology (ACIT), Siemens Healthcare AG, Lausanne, Switzerland, ³Division of Cardiology and CMR-Center, Lausanne University Hospital (CHUV), Lausanne, Switzerland, ⁴Center for Biomedical Imaging (CIBM), Lausanne, Switzerland

Robust visualization of the coronary vessels is challenging due to cardiac and respiratory motion. Several strategies exist that resolve respiratory motion (XD-GRASP) or compensate for it using N-dimensional image-based navigators to correct for N dimensions of motion. We present a novel self-navigation method wherein the minimization of an image metric is used to estimate 3D non-rigid respiratory motion from a 1D navigator signal (focused navigation: fNAV). We validate fNAV for free-breathing cardiac triggered whole-heart CMRA in a realistic numerical phantom, demonstrate its use in cohorts of healthy volunteers and patients, and quantitatively compare fNAV reconstructions to XD-GRASP.

Aurelien Bustin¹, Reza Hajhosseiny¹, Imran Rashid¹, Gastao Cruz¹, Ronak Rajani¹, Tevfik Ismail¹, René Botnar¹, and Claudia Prieto^1
1Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom

The recent integration of undersampled acquisitions with image-navigators and non-rigid motion-correction have enabled free-breathing 3D whole-heart coronary MR angiography (CMRA) with sub-millimeter isotropic resolution in clinically feasible scan times in healthy subjects. The high acceleration factor and spatial resolution however must be balanced with the need for a robust and high-quality image reconstruction. We sought to assess whether this highly accelerated sub-millimeter isotropic resolution contrast-free CMRA framework could reliably improve the visualization of coronary arteries in comparison to lower resolution (and lower acceleration factor) CMRA in patients with suspected coronary artery disease who underwent CT coronary angiography.

Yoshiaki Morita¹, Hideki Ota¹, Atsuro Masuda¹, Takashi Nishina², Sho Tanaka², Yuichi Yamashita², Yoshimori Kassai², and Kei Takase^1
1Department of Radiology, Tohoku University Hospital, Sendai, Miyagi, Japan, ²Canon Medical Systems Corporation, Otawara, Tochigi, Japan

Our proposed Whole Heart Coronary MR Angiography with 100% respiratory gating efficiency using Fast 3D Wheel data acquisition implementing denoising deep learning reconstruction allowed the rapid data acquisition consistently within 3 minutes in spite of irregular breath pattern while maintaining the image quality and contrast ratio of conventional scan. This technique will improve the ease-of-use of coronary artery imaging for practical use.

Hao Li¹, Martin John Graves², Nadeem Shaida², Akash Prashar², David John Lomas¹, and Andrew Nicholas Priest^2
1Department of Radiology, University of Cambridge, Cambridge, United Kingdom, ²Department of Radiology, Addenbrooke’s Hospital, Cambridge, United Kingdom

We implemented two advanced reconstruction methods for highly accelerated subtractive NCE-MRA, which can exploit the sparsity of subtracted angiograms. One method is based on k-space subtraction of complex raw data with phase and intensity correction (KSPIC). Another method is to reconstruct bright- and dark-blood data with an additional magnitude subtraction term in the cost function to exploit the sparsity. The performance of the two methods was evaluated in both retrospective and prospective accelerated datasets using quantitative metrics and qualitative scoring. Compared with conventional methods, they both showed improved image reconstruction quality, while KSPIC had the best performance.

Sen Jia^1,2, Zhilang Qiu^1,2, Lei Zhang², Xin Liu², Hairong Zheng², and Dong Liang^2
1University of Chinese Academy of Sciences, Shenzhen, China, ²Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China

Joint intracranial and carotid 3D vessel wall imaging (VWI) with an isotropic spatial resolution between 0.5-0.6 mm is promising in diagnosing arterial wall diseases but leads to clinically impractical scan time. CAIPIRINHA 3x3 undersampling with elliptical scanning is used to expedite the VWI by 11-fold without less sampling the high-frequency region of k-space. Iterative L1-ESPIRiT algorithm is employed for reconstruction with GRAPPA result as the initialization. The scheme of Iterative Feature Refinement is embedded into L1-ESPIRiT iteration to avoid potential over-smoothing issue. Finally, the 3D 11x VWI scan at an isotropic resolution of 0.6 mm takes only 3.5 minutes.

Zhensen Chen¹, Zechen Zhou², Niranjan Balu¹, Haikun Qi³, Baocheng Chu¹, Thomas S Hatsukami⁴, and Chun Yuan^1
1Vascular Imaging Lab and BioMolecular Imaging Center, Radiology, University of Washington, Seattle, WA, United States, ²Philips Research North America, Cambridge, MA, United States, ³Biomedical Engineering, King's College London, London, United Kingdom, ⁴Surgery, University of Washington, Seattle, WA, United States

In this study, a whole brain sequence named iSNAP, with 0.8 mm isotropic voxel size and 6 min 30 sec acquisition time, was developed to simultaneously obtain four different image contrasts (dynamic MRA [dMRA] for blood flow monitoring, MRA for luminal stenosis measurement, black blood image for vessel wall [VW] measurement and T1W for brain structural imaging). Preliminary testing results on a healthy volunteer and two patients with cerebrovascular diseases demonstrated the feasibility and potential of the sequence.

Chen Huang¹, Guoxi Xie², Xueping He¹, Yufeng Ye¹, Wei Deng¹, Jianke Liang¹, Zhuonan He¹, Xin Liu³, Debiao Li⁴, Zhaoyang Fan⁴, and Hanwei Chen^1
1Guangzhou panyu central hospital, Guangzhou, China, ²Guangzhou medical university, Guangzhou, China, ³Shenzhen Institutes of Advanced Technology, Shenzhen, China, ⁴Cedars-Sinai Medical Center, Los Angeles, CA, United States

The present study aims to evaluate the outcome of thrombolysis for acute DVT using the thrombus signal characteristics generated by a T1-weighted MR black-blood thrombus imaging (BTI) technique.The patients were divided into iso- or hyper-intense thrombus groups according to  the BTI images and the additional CDT were performed .The thrombolysis ratio  of patients with iso-intense signals was significantly higher than hyper-intense ones .However, the patients with iso-intense thrombus had a  lower incidence rate of PTS at 6  and 12 months.So,the thrombus signal characteristics on BTI images maybe used to predict the outcome of  DVT treated with the lytic therapy.

Claudia Calcagno¹, John David², Abdallah Motaal², Thijs Beldman², Alexandra Corbin¹, Arnav Kak¹, Sarayu Ramachandran¹, Alison Pruzan¹, Raphael Soler¹, Christopher Faries¹, Zahi A. Fayad¹, Willem Mulder¹, and Gustav Strijkers^2
1Icahn School of Medicine at Mount Sinai, New York, NY, United States, ²University of Amsterdam, Amsterdam, Netherlands

Enhanced endothelial permeability is an important hallmark of atherosclerotic plaques at high-risk for causing severe cardiovascular events. Here we present a the application of a novel, self-gated DCE-MRI acquisition combined with compressed sensing reconstruction to quantify endothelial permeability in the mouse aortic root. In a longitudinal natural disease progression study in ApoE-/- mice, we find that plaque contrast agent washout computed from this acquisition changes significantly over time, with washout being slower in older mice.