Jing Liu¹, Valentina Pedoia¹, Ursula Heilmeier¹, Favian Su¹, Sameer Khanna², John Imboden³, Jonathan Graf³, David Saloner¹, and Xiaojuan Li^1
1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, ²University of California Berkeley, Berkeley, CA, United States, ³Medicine, University of California San Francisco, San Francisco, CA, United States

We have achieved highly accelerated 3D dynamic contrast enhanced (DCE) wrist MRI in Rheumatoid Arthritis (RA) patients with improved image spatial (0.3x0.3x1.5mm) and temporal resolution (5s), with an acceleration factor R=20. Evaluation of neovascularization and perfusion in RA joints demonstrated that the improved images could provide accurate assessment of the RA progression.

Peter Bannas^1,2, Laura C Bell³, Kevin M Johnson³, Mark L Schiebler¹, Christopher J François¹, Utaroh Motosugi¹, Dan Consigny¹, Scott B Reeder^1,3, and Scott K Nagle^1,3
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

Ultrashort echo time (UTE) MRI has been used successfully to image very short T2* tissues, including human lungs. In this animal study in canines we demonstrate the feasibility of using 3D radial UTE MRI to detect pulmonary emboli (PE) while simultaneously imaging the lung parenchyma with high image quality. This free-breathing method is implemented on commercially available hardware. The image quality and PE detection efficacy were compared to conventional MR angiography, using CTA as the standard of reference.

Markus Henningsson¹, Kostas Bratis¹, Eike Nagel¹, and Rene Botnar^1
1Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom

Respiratory motion remains a major impediment in a substantial amount of patients undergoing coronary magnetic resonance angiography. In this work, we show preliminary clinical results from an inline implementation of image-based respiratory motion correction and gating in 25 patients with coronary artery disease. The motion compensation consisted of left-right and foot-head translational correction and diminishing variance gating assuming 50% scan efficiency. The images were compared to gold standard CT and X-ray and yielded a per vessel specificity of 92% and sensitivity of 98%, and per patient specificity of 86% and sensitivity of 94%.

Yutaka Natsuaki¹, Xiaoming Bi¹, David M Grodzki², Aurelien F Stalder², and Gerhard Laub^1
1Siemens Healthcare, Los Angeles, CA, United States, ²Siemens Healthcare, Erlangen, Germany

Despite being accepted as a current clinical gold standard for the intracranial non-contrast MR Angiography (MRA), 3D Time of Flight (3D TOF) sequence has well-known flow dephasing artifacts in lumen, in particular in the tortuous carotid arteries. Recently developed Zero-TE (ZTE) sequences (e.g. PETRA) and their subtraction-based MRA applications (e.g. PETRA qMRA) can potentially solve this problem, as they are inherently immune to flow dephasing. Through volunteer validation studies vs the 3D TOF (n=5), the current work demonstrates that the optimized PETRA qMRA can generate the one of the kind, zero-flow dephasing non-contrast MRA.

Ioannis Koktzoglou^1,2, Ian G Murphy^1,3, David Grodzki⁴, Shivraman Giri⁵, and Robert R Edelman^1,3
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, ²Radiology, The University of Chicago Pritzker School of Medicine, Chicago, IL, United States, ³Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States, ⁴Healthcare Sector, Siemens AG, Erlangen, Germany, ⁵Siemens Healthcare, Chicago, IL, United States

Magnetic resonance angiography (MRA) is an accurate diagnostic modality for evaluating stenotic disease of the extracranial carotid arteries. For patients in whom the administration of gadolinium-based contrast agents is contraindicated, time-of-flight MRA is commonly used. However, image quality is variable and only a limited vascular region is depicted. We describe an alternative approach for non-contrast MRA using ultra-short echo time 3D point-wise encoding time reduction with radial acquisition (PETRA) sequence that allows for evaluation of the carotid arteries using both bright- and dark-blood projection images, and eliminates signal loss near severe stenoses.

Shuo Chen¹, Xihai Zhao¹, Niranjan Balu², Haining Liu², Zechen Zhou¹, Jinnan Wang^2,3, Rui Li¹, Chun Yuan^1,2, and Huijun Chen^1
1Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, Beijing, China,²Department of radiology, University of Washington, Seattle, United States, ³Philips Research North America, Briarcliff Manor, NY, United States

In carotid atherosclerotic plaque, surface conditions such as juxtaluminal calcification (JCA) and ulceration are believed to be linked to plaque vulnerability. Conventionally, multi-contrast sequences (T1w-TSE, T2w-TSE, 3D TOF) are used to determine the plaque components and vulnerability. However, conventional multi-contrast is constrained by limited longitudinal coverage, long acquisition time and inter-scan motion. Recently, a simultaneous non-contrast angiography and intraplaque hemorrhage (SNAP) sequence was proposed for carotid artery imaging. In this work, we sought to evaluate the feasibility of carotid plaque surface condition evaluation using SNAP sequence alone.

Yuriko Suzuki¹, Tetsuo Ogino¹, James Alastair Meakin², Akira Suwa¹, Daigo Ushijima¹, and Marc Van Cauteren^3
1Healthcare, Philips Electronics Japan, Minato-ku, Tokyo, Japan, ²Philips Healthcare Netherlands, Best, Netherlands, ³Philips Healthcare Asia Pasific, Tokyo, Japan

In this work, we investigated how we further optimized the 4D-MRA sequence which halve the scan time by acquiring the labeled and control images in a single Look-Locker like multiple acquisition to counter the limitations, such as fat signal artifacts due to the chemical shift of the labeling pulse and shorter labeled bolus due to its limited labeling slab thickness, which happened due to the sequence design of this sequence. By optimizing the labeling pulse, this single acquisition technique with halved scan time could generate 4D-MRA image with quality very similar to the conventional ASL technique.

Hao Tang¹, Daoyu Hu¹, Zi Wang¹, Xiaoyan Meng¹, and Yanchu Wang^1
1Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China

Unenhanced MR angiography with spatial labeling with multiple inversion pulses (SLEEK) is a reliable method for depicting anatomy and complications from renal vascular transplant compared with digital subtraction angiography and intraoperative results. In a study of 75 patients who underwent renal transplantation, we found that unenhanced MR angiography with SLEEK enabled visualization of small branches within the transplant renal parenchyma and subtle accessory renal arteries. The method may show transplant renal veins while suppressing the signal from the inflowing arterial vein. SLEEK MR angiography is a promising alternative technique for assessing renal vessels in patients with renal transplants.

Pim van Ooij^1,2, Julio Garcia², Susanne Schnell², Jeremy D Collins², James C Carr², Michael Markl^2,3, and Alex J Barker^2
1Radiology, Academic Medical Center, Amsterdam, Netherlands, ²Radiology, Northwestern University, Chicago, IL, United States, ³Biomedical Engineering, Northwestern University, Chicago, IL, United States

Age-related changes in 4D flow MRI derived peak/mean velocity, Wall Shear Stress (WSS), velocity Time To Peak (TTP) and Mid-Ascending Aortic diameter (MAA) were investigated in 60 healthy volunteers (19-79 years old). A significant increase in peak velocity (R=0.39,P=0.001), decrease in mean velocity (R=0.53, P<0.001), WSS (R=0.59, P<0.001), TTP (R=0.39, P=0.001) and MAA (R=0.57, P=<0.001) was found with increasing age. The results show the importance of matching patient age to the appropriate control group.

Nicholas Scott Burris¹, Petter Dyverfeldt², and Michael D Hope^1
1Radiology, University of California San Francisco, San Francisco, CA, United States, ²Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden

Bicuspid aortic valve (BAV) is a common congenital cardiac abnormality associated with abnormal aortic flow, increased aortic stiffness and valvular dysfunction, which may predispose to abnormal ventricular-arterial coupling. Wave intensity analysis (WIA) was used to measure a maker left ventricular function, forward compression wave (FCW), using 2D phase-contrast MRI. We found decreased average FCW values in BAV patients compared to normal patients. Amongst BAV patients, two features of BAV-aortopathy (aortic stiffness and aortic diameter) were found to predict decreases in FCW. WIA may identify early and adverse changes in ventricular-arterial coupling in patients with BAV that would otherwise go unnoticed.