Jia Liu¹, Kai Zhao¹, Wei Li¹, Zhongxu Bi¹, Jinxia Zhu², Xiaoye Wang³, and Jianxing Qiu^1
1Peking University First Hospital, Beijing, China, ²MR Collaboration, Siemens Healthcare Ltd, Beijing, China, ³MR APP, Siemens Healthcare Ltd, Beijing, China

We investigated the feasibility and clinical value of free-breathing non-contrast MR pulmonary angiography (MRPA). The subjective diagnostic image quality values, evaluated by two radiologists, showed excellent consistency. Non-contrast MRPA can provide acceptable image quality that can be applied broadly in clinical medicine. 

El-Sayed H Ibrahim¹, Xiaolong Wang¹, and Bo Wang^1
1Medical College of Wisconsin, Milwaukee, WI, United States

Vascular tissue-engineering provides an alternative solution to replace autologous vessels via developing an artificial vascular graft. To examine the in-vivo fate and understand the clinical potential of the artificial vascular graft, the graft was implanted into the abdominal aorta of Sprague-Dawley rats by end-to-end anastomosis. The goal of this study was to evaluate compliance and vessel wall stiffness in the artic graft and compare results to native aorta using MRI. The results demonstrated that the developed graft has biomechanical characteristics similar to those in native aorta, which may represent a potential avenue to construct a flexible vascular graft in patients.

Cyril Tous, PhD¹, Ivan Dimov¹, Ning Li, PhD¹, Simon Lessard, PhD¹, An Tang, MD, MSc^1,2, Samuel Kadoury, PhD^1,3, and Gilles Soulez, MD,MSc^1,2
1Radiology, Centre de recherche du Centre hospitalier de l’Université de Montréal, Montreal, QC, Canada, ²Radiology, Université de Montréal, Montréal, QC, Canada, ³Polytechnique Montréal, Montréal, QC, Canada

Turbulent flow undermines steering of magnetic microrobots across bifurcations using the MRI gradients. A partial inflated balloon can reproduce a blood flow controlling method in vivo, to increase the targeted success rate of embolization by microrobots. At 3T MRI, 4D flow reveals that vortices in front of the catheter were generated. These series of vortices are also confirmed through by ink injection and under videos capture. At 4 mm diameter, 4D flow and cine phase are reproducible for average velocity and net flow at 0.8mm² in plane resolution. These in vitro results can be used to refine 4D flow models.

El-Sayed H Ibrahim¹, Jamasp Azarnoosh², Arash Hassankiadeh¹, Pierre Croisille³, Jadranka Stojanovska⁴, and John LaDisa^2
1Medical College of Wisconsin, Milwaukee, WI, United States, ²Marquette University, Milwaukee, WI, United States, ³Jean-Monnet University, Lyon, France, ⁴University of Michigan, Ann Arbor, MI, United States

Aortic coarctation (CoA) is a congenital vascular disease characterized by severe narrowing of the proximal descending thoracic aorta, which affects 5,000-8,000 births annually in USA. Patients with CoA can have altered hemodynamics and remodeled left ventricle from increased afterload. In this study, we investigate the impact of CoA on cardiovascular parameters using rabbit models of treated and untreated CoA. The results showed that cardiovascular parameters can normalize in treated CoA compared to untreated cases and that myocardial strain and aortic blood velocity are sensitive parameters for differentiating between treated and untreated CoA as well as the severity of coarctation.

Tianyi Zhou¹, Liam Timms¹, Valur Olafsson², Fred Bidmead², Vishala Mishra³, Ravi T Seethamraju⁴, Mukesh Harisinghani³, and Srinivas Sridhar^1
1Department of Physics, Northeastern University, Boston, MA, United States, ²Northeastern University Biomedical Imaging Center, Boston, MA, United States, ³Department of Radiology, Massachusetts General Hospital, Boston, MA, United States, ⁴Siemens Medical Solutions, Boston, MA, United States

A contrast-enhanced MRA protocol with Ultrashort Time-to-Echo (UTE) was optimized on phantoms covering a range of ferumoxytol concentrations for abdominal imaging. This approach produces images with high SNR (~ 4166) at clinical concentrations. The protocol was applied in vivo to human subjects for abdominal vascular imaging. Acquired human images demonstrated great delineation of central and peripheral vessels in the liver, kidneys and other abdominal organs. The combination of an optimized UTE sequence and the blood-pool kinetics of ferumoxytol enables high-resolution vascular imaging across the entire abdomen with maximized image quality. This technique could potentially aid in characterization of vascular diseases.

Mubeena Abdulkarim¹, Munes Fares¹, Mohammed Hussain^1,2, Gerald Greil¹, Tarique Hussain¹, and Joshua Greer^1
1Pediatric Cardiology, University of Texas Southwestern, Dallas, TX, United States, ²Kafrelsheikh univeristy, Kafr El Sheikh, Egypt

3D whole-heart bSSFP (3DWH) is the clinical standard in the evaluation of anatomy in congenital heart disease (CHD), but can be time consuming to acquire. A compressed sense (CS-SENSE) algorithm to accelerate standard SENSE technique recently became commercially available, and was shown to accelerate clinical protocols in adults.  3DWH accelerated by CS-SENSE factor of 3.5 provided visualization of all structures with no degradation in CNR or image quality while reducing scan time by approximately 25% in pediatric congenital heart disease.

Takashi Namiki¹, Masami Yoneyama¹, Hiroshi Hamano¹, Tomohiro Mochizuki¹, Yuki Ito¹, Mai Nishihara¹, and Yasutomo Katsumata^2
1Philips Japan, Tokyo, Japan, ²Philips Healthcare, Best, Netherlands

Inflow magnetic resonance angiography (MRA) plays an important role in catheter insertion for intracranial endovascular treatment in the visualization of blood vessels at the aortic arch bifurcation. However, it is often difficult to accurately determine vascular stenosis due to respiratory artifacts and surrounding fat. In this study, we employ 3-dimensional time of flight  MRA using radial-based gradient echo pulse sequence with modified DIXON (TOF-RADIXON) compared it with 3-dimensional time of flight MRA (TOF-MRA). The experimental results using TOF-RADIXON showed that ability to visualize blood vessels is more promising than TOF-MRA.

yunfeng shen¹ and Weiqiang Dou^2
1shandong university, Jinan, China, ²GE Healthcare, Beijing, China

Anterolateral thigh (ALT) flap has been widely used in reconstructive surgery for head and neck region and the extremities. However, the difficulties during the dissection of this flap were often associated with various vascular anatomies and frequent intramuscular course of perforators [1]. In this study, using a novel differential subsampling with cartesian ordering (DISCO) contrast enhancement magnetic resonance angiography, the patterns of lateral circumflex femoral artery and its branches were clearly identified, and were consistent with operative findings. Therefore, DISCO imaging can be an accurate and compatible method for perforators imaging preoperatively prior to ALT flaps.

Jihun Kwon¹, Masami Yoneyama¹, Yasuhiro Goto², Yutaka Hamatani², Isao Shiina², Kazuo Kodaira², Takumi Ogawa², Michinobu Nagao³, Kayoko Abe³, Takashi Namiki¹, and Marc Van Cauteren^4
1Philips Japan, Tokyo, Japan, ²Department of Radiological Services, Tokyo Women’s Medical University, Tokyo, Japan, ³Department of Diagnostic Imaging and Nuclear Medicine, Tokyo Women’s Medical University, Tokyo, Japan, ⁴Philips Healthcare, Best, Netherlands

Magnetic resonance venography (MRV) is often used to assess venous anatomy and pathology. In this study, we developed a 2D dual-echo balanced-turbo field-echo (TFE) mDIXON (bTFE DIXON) sequence to rapidly acquire high SNR MRV of lower extremities, without using cardiac gating and respiratory compensation. We also proposed a new post-processing technique, histogram similarity-based swap correction (HISSCO), to detect and correct water-fat slice swap artifact associated with the mDIXON technique. Our results showed that combined with HISSCO, the bTFE DIXON sequence can potentially be a clinically useful sequence for assessing the venous pathology of the lower extremities.

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

A time-efficient high-resolution 3D fresh-blood imaging technique is proposed. The acquisition matrix size was increased from 256 to 512 in both readout and in-plane phase-encoding dimensions. Imaging efficiency was improved using compressed sensing together with k-space subtraction, so that the acquisition time is not prolonged compared to standard-resolution protocols. To avoid flow-related arterial signal voids, velocity-compensation gradients were used instead of velocity-spoiling gradients, and the spoiler gradients in the slice-encoding direction were increased. By decreasing the pixel size, the overall vessel sharpness and depiction of small vessels were significantly improved, at the cost of reducing the contrast-to-noise ratio.

Akos Varga-Szemes¹, Pascale Aouad², U. Joseph Schoepf¹, Tilman Emrich¹, Basel Yacoub¹, Thomas M Todoran³, Ioannis Koktzoglou⁴, and Robert R Edelman^4
1Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, United States, ²Northwestern University, Chicago, IL, United States, ³Department of Medicine, Medical University of South Carolina, Charleston, SC, United States, ⁴Department of Radiology, Northshore University HealthSystem, Evanston, IL, United States

2D quiescent-interval slice-selective (QISS) MRA is an established technique in peripheral artery disease (PAD), however, its slice thickness is inferior to that used for computed tomography angiography (CTA). The prototype thin-slab stack-of-stars (tsSOS) QISS technique achieves CTA-like slice thickness. In this three-center study, we compared 2D-QISS and tsSOS-QISS MRA for the detection PAD in 23 patients. Overall image quality was not different between tsSOS-QISS and 2D-QISS. AUCs for PAD detection were not statistically different between the techniques (P=0.336). Our results indicate that 3D tsSOS-QISS provides similar accuracy in patients with PAD to a standard commercially available 2D-QISS technique.

Yasuhiro Goto¹, Michinobu Nagao¹, Masami Yoneyama², Yasutomo Katsumata², Isao Shiina¹, Kazuo Kodaira¹, Yutaka Hamatani¹, Takumi Ogawa¹, Mamoru Takeyama¹, Isao Tanaka¹, and Shuji Sakai^1
1Women's Medical University Hospital, tokyo, Japan, ²Philips Japan, tokyo, Japan

We investigated whether non-contrast, high resolution PPU-triggered 4D-peripheral MRA using Retrospective EPI (REPI). REPI 4D-peripheral MRA with VENC of 10 cm/s showed higher vascular conspicuity compared with the conventional methods.

Yutaka Hamatani¹, Kayoko Abe², Masami Yoneyama³, Christoph Katemann⁴, Shuo Zhang⁴, Yasuhiro Goto¹, Michinobu Nagao², Isao Shiina¹, Kazuo Kodaira¹, Takumi Ogawa¹, Mamoru Takeyama¹, Isao Tanaka¹, and Shuji Sakai^2
1Department of Radioligical Services, Tokyo Women's Medical University Hospital, Tokyo, Japan, ²Department of Diagnostic imaging & Nuclear Medicine, Tokyo Women's Medical University Hospital, Tokyo, Japan, ³Philips Japan, Tokyo, Japan, ⁴Philips Healthcare, Hamburg, Germany

Magnetic resonance angiography (MRA) is essential to characterize luminal changes and detect abnormalities in peripheral vascular diseases. However, clear depiction of the vascular structures without contrast within a short scan time remains challenging and is often limited by complicated exam and long procedure time. In this study, we employ planning-less REACT-MD (Relaxation-Enhanced Angiography without Contrast and Triggering with Multiple Delays) with simultaneous non-contrast MRA and black-blood imaging for fast and simple run-off exams of the lower extremities without additional scout acquisition and volume planning, aiming to provide multi-contrast images with diagnostic quality and simplified clinical workflow.

Kavya Sinha¹, Christof Karmonik², Alan B Lumsden¹, and Trisha Roy^1
1DeBakey Heart & Vascular Center, Houston Methodist Hospital, Houston, TX, United States, ²Translational Imaging Center, Houston Methodist Research Institute, Houston, TX, United States

Peripheral arterial disease (PAD) has been estimated to reduce quality of life in approximately 2 million symptomatic Americans, with millions more expected to suffer PAD-associated impairment. Anatomic characteristics of PAD lesions influence clinical outcomes, including the success and durability of endovascular treatments. Current clinical imaging modalities CTA, fluoroscopy and ultrasound do not depict plaque characterization to the extent of MRI. In this abstract we show how clinical ultra-high field protocol can be used for visualization and quantification of lesion components in peripheral artery disease.

Lichen Zhang^1,2, Yongjun Han³, Maobin Guang⁴, Zhu Zhu⁴, Jianming Cai⁵, and Xihai Zhao^6
11Medical School of Chinese PLA, Beijing, China., Beijing, China, ²Department of Radiology, the Fifth Medical Center, Chinese PLA General Hospital, Beijing, China., Beijing, China, ³Department of radiology, Aerospace Center Hospital, Beijing, China., Beijing, China, ⁴Department of Radiology, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China, Yangzhou, China, ⁵Department of Radiology, the Fifth Medical Center, Chinese PLA General Hospital, Beijing, China., Beijing, China, Beijing, China, ⁶Center For Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China, Beijing, China

We sought to investigate the differences of plaque characteristics in different femoral artery segments between males and females using magnetic resonance vessel wall imaging. The 3D-MERGE was acquired from the common femoral artery to the popliteal artery. We compared the differences of femoral artery plaque characteristics between men and women. Men had significantly larger area of lumen and wall, but smaller normalized wall index compared with women. Men have larger vessel size but lower plaque burden then women, more attention is needed to be paid to asymptomatic elderly women.

Evan Norris¹, Guenther Schneider², Toshimasa Clark¹, Miles Kirchin³, Gregory Wilson⁴, and Jeffrey Maki^1,4
1Radiology, University of Colorado, Aurora, CO, United States, ²University Hospital of Saarland, Homburg, Germany, ³Bracco Imaging, Milan, Italy, ⁴University of Washington, Seattle, WA, United States

Recent insight into the behavior of blood R₁ and R₂* predicts the precise manner that signal intensity increases, plateaus, and ultimately diminishes with increasing gadolinium-based contrast agent concentration ([GBCA]). This has important implications for optimal GBCA utilization and administration in contrast enhanced MRA (CE-MRA). We validate these theoretical constructs in an in vivo pig model where time resolved CE-MRA and [GBCA] (via mass spectrometry) are acquired simultaneously, demonstrating that the theoretical relationship between [GBCA] and R₁, R₂* as applied to first pass CE-MRA allows for accurate predictions of CE-MRA signal intensity for any given blood concentration across three different GBCAs. 

Zechen Zhou¹, Niranjan Balu², Holger Eggers³, Peter Börnert³, Thomas S. Hatsukami², and Chun Yuan^2
1Philips Research North America, Cambridge, MA, United States, ²Vascular Imaging Lab, University of Washington, Seattle, WA, United States, ³Philips Research Hamburg, Hamburg, Germany

In this work, a dual-echo 3D-MERGE with adiabatic flow suppression was developed to improve the image quality of large-coverage carotid vessel wall imaging (VWI). The initial experiments on plaque specimen  and healthy volunteers have demonstrated its potential for plaque component analysis and feasibility to achieve isotropic 0.8mm VWI with improved fat/flow suppression and additional quantitative fat fraction/field maps by using this ~4min large-coverage scan.

Dongye Li¹, Huiyu Qiao², Yongjun Qiao², Hualu Han², Dandan Yang², Jingli Cao³, Huimin Xu⁴, Tao Wang⁴, Jun Shen¹, and Xihai Zhao^2
1Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, ²Department of Biomedical Engineering, Center for Biomedical Imaging Research, Tsinghua University School of Medicine, Beijing, China, ³China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China, ⁴Peking University Third Hospital, Beijing, China

It is important to accurately identify carotid necrotic core (NC), intraplaque hemorrhage (IPH) due to its strong association with ischemic stroke. Multi-contrast cardiovascular magnetic resonance (CMR) vessel wall imaging has become an effective non-invasive technique to assess carotid plaque components. The aim of this study sought to confirm criteria of signal intensity threshold of all plaque components by comparing multiple tissue references validated by histology. This study afforded a standard of the signal intensity threshold ratio of carotid plaque components compared to reference tissues on multi-contrast cardiovascular MR imaging, and provides the basis for accurate identification of crucial plaque components.

Takashi Namiki¹, Hiroshi Hamano¹, Naoki Udo², Inka Ristow³, Felicia-Marie von Düring³, Alexander Lenz³, Shuo Zhang⁴, and Masami Yoneyama^1
1Philips Japan, Tokyo, Japan, ²Department of Radiological technology , Yuuai Medical Center, Okinawa, Japan, ³Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Hospital Hamburg-Eppendorf, Hamburg, Germany, ⁴Philips, Hamburg, Germany

Black-blood MRI is essential to characterize vessel wall in vivo and to identify vascular abnormalities. However, clear depiction of the wall structures in the thoracoabdominal region remains challenging and often suffers from pulsation or breathing artifacts. In this study, we employ motion sensitized driven equilibrium (MSDE) preparation technique and combine with radial-based 3D gradient- and 2D spin-echo imaging pulse sequences. Initial results in healthy volunteer and patients are reported in comparison to the conventional bright-blood and Cartesian techniques, which have shown promise in detection of vessel wall lesions before or after injection of contrast agent.

Alessandra Caporale¹, Michael Langham¹, and Felix W Wehrli^1
1Radiology, Laboratory for Structural, Physiologic and Functional Imaging, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States

To investigate the effects of chronic exposure to cigarette smoke or electronic cigarette aerosol on the vascular endothelium, various MRI parameters were examined in an ongoing study involving healthy young people (mean age<30y). Peripheral, cerebrovascular reactivity, and central aortic stiffness were evaluated comparing smokers (N=11) and vapers (N=15) to their nonsmoking-peers (N=31).  There were no significant differences between groups, but hyperemic blood flow acceleration trended lower in smokers/vapers while arterial stiffness trended higher in smokers, relative to nonsmokers. The findings may suggest that exposure in these young subjects was not be sufficient to cause measurable adverse effects on the endothelium.