Masanobu Nakamura¹, Masami Yoneyama¹, Tomoyuki Okuaki¹, Takashi Tabuchi¹, Atsushi Takemura², Makoto Obara², and Junko Ogura^1
1Medical Satellite Yaesu Clinic, Chiyoda-ku, Tokyo, Japan, ²Philips Electronics Japan, Tokyo, Japan

Detailed information on anatomy and hemodynamics in cerebrovascular disorders such as AVM and Moyamoya disease is mandatory for defined diagnosis and treatment planning. Arterial spin labeling technique has come to be applied to MRA and perfusion imaging in recent years. Those non-contrast techniques are, however, mostly limited to a single frame images. Recently we have proposed non-contrast time-resolved MRA technique termed Contrast inherent inflow enhanced multi phase angiography combining spatial resolution Echo planar imaging based signal targeting and alternating radiofrequency (CINEMA-STAR). CINEMA-STAR can extract the blood flow in the major intracranial arteries at an interval of 50 ms and thus permitted us to observe vascular construction in full by preparing MIP images of axial acquisitions with 1.6 �~ 1.6 mm2 spatial resolution. This preliminary study demonstrated the usefulness of CINEMA-STAR technique in evaluating the cerebral vascularture.

David Saloner^1,2, Daniel Hurwit^1,2, Vitaliy Rayz^1,2, Loic Boussel³, Alastair Martin¹, William Young⁴, Wade Smith⁵, Nerissa Ko⁵, and Michael Lawton^6
1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, ²Radiology, VA Medical Center San Francisco, San Francisco, CA, United States, ³Radiology, Louis Pradel Hospital, Lyon, France, ⁴Anesthesiology, University of California San Francisco, San Francisco, CA, United States, ⁵Neurology, University of California San Francisco, San Francisco, CA, United States, ⁶Neurosurgery, University of California San Francisco, San Francisco, CA, United States

Patients with untreated intracranial aneurysms were imaged at serial intervals to monitor changes in those aneurysms over time. CE-MRA and balanced steady state imaging were performed to assess changes in lumen and intralumenal thrombus. In 36% of interval studies there were no changes; in 30% there was a reduction in lumenal volume secondary to thrombus deposition; and the remaining subjects showed lumenal growth both for aneurysms in the anterior and posterior circulation. 3D MRA/I methods are powerful tools for the non-invasive monitoring of evolution of vascular disease.

Ann-Kathrin Homagk¹, Moritz Cornelius Berger¹, Lars Gerigk¹, Onur Ozyurt², Lydia Schuster¹, Wolfhard Semmler¹, and Michael Bock^1
1German Cancer Research Center, Heidelberg, Germany, ²Bogazici University, Istanbul, Turkey

In this work, we present how the challenges of acquiring dynamic angiography images at ultra-high fields can be overcome using an adapted STAR sequence. The cerebral vasculatures of three volunteers were imaged in a 7 Tesla MR system with an in-plane resolution of 0.56x0.56 mm² so that small peripheral vessels could be visualized. The results show that with the adapted sequence, high-resolution dynamic ASL imaging at 7 Tesla is feasible within an acquisition time of 6:45 min.

Thomas William Okell¹, Peter Schmitt², Xiaoming Bi³, Michael Andrew Chappell^1,4, Rob Hendrikus Tijssen¹, Karla L Miller¹, and Peter Jezzard^1
1FMRIB Centre, Department of Clinical Neurosciences, University of Oxford, Oxford, Oxfordshire, United Kingdom, ²MR Application & Workflow Development, Siemens AG, Healthcare Sector, Erlangen, Germany, ³Cardiovascular MR R&D, Siemens Healthcare, Chicago, IL, United States, ⁴Institute of Biomedical Engineering, University of Oxford, Oxford, Oxfordshire, United Kingdom

The ability to assess the functional status of cerebral arteries is important for patients with cerebrovascular disease. In this work we combine a vessel-encoded arterial spin labeling preparation with a four-dimensional balanced steady-state free precession readout to obtain dynamic vessel selective angiograms of the four major arteries feeding the brain non-invasively and without the use of contrast agents. This sequence may also be used in dynamic 2D mode to considerably accelerate the acquisition, enabling it to fit easily within a busy clinical protocol.

Vitaliy L. Rayz¹, Loic Boussel², Gabriel Acevedo-Bolton¹, Alastair J Martin¹, and David Saloner^1
1Radiology, University of California, San Francisco, CA, United States, ²Radiology, Louis Pradel Hospital, CREATIS-LRMN, UMR CNRS 5515, INSERM U630, Lyon, France

Phase-contrast MR velocimetry is capable of measuring 3D velocity fields, but limited resolution leads to errors in wall shear stress estimation. An accurate estimation of the wall shear with CFD modeling requires significant computation times. PC-MRV and CFD methods were combined by using measured PC-MRV data as an initial approximation for the iterative solution in 3 patient-specific cerebral aneurysm models. The flow fields obtained with CFD corresponded to MRV measurements and computational time required to reach convergence was reduced by up to 25%.

Masanobu Nakamura¹, Masami Yoneyama¹, Tomoyuki Okuaki¹, Takashi Tabuchi¹, Atsushi Takemura², Makoto Obara², Junko Ogura¹, and Satoshi Tsutsumi^3
1Medical Satellite Yaesu Clinic, Chiyoda-ku, Tokyo, Japan, ²Philips Electronics Japan, Tokyo, Japan, ³Neurosurgery, Juntendo University Urayasu Hospital, Chiba, Japan

Detailed information on anatomy and hemodynamics in cerebrovascular disorders such as AVM and Moyamoya disease is mandatory for defined diagnosis and treatment planning. Currently most widely used non-contrast MRA techniques are TOF and PC. Those non-contrast techniques are, however, mostly limited to a single frame images. Recently we have proposed 3D volumetric non contrast time-resolved MRA technique termed Contrast inherent inflow enhanced multi phase angiography combining multiple phase FAIR (CINEMA-FAIR). CINEMA technique combines ASL with 3D segmented T1 weighted gradient echo sequence (3D T1 TFE). FAIR preparation scheme with the Look-Locker sampling was used for spin tagging in this study. CINEMA could extract the blood flow in the whole brain at an interval of 100 ms and thus permitted us to observe vascular construction in full by preparing MIP images. This preliminary study demonstrated the usefulness of CINEMA-FAIR technique in evaluating the cerebral vascularture.

Daniel Kopeinigg^1,2, and Roland Bammer^1
1Stanford University, Stanford, CA, United States, ²Institute of Medical Engineering, Graz, Styria, Austria

Imaging of the intracranial arteries is frequently performed with 3D TOF angiography. In this work, we used Shinnar-Le-Roux (SLR) transform to design a minimum-phase small tip angle ramped excitation pulse with a built in one-sided saturation band to either suppress the venous/or arterial signal in 3D TOF acquisitions. Our results showed that this RF pulse is veryeffective in saturating superior inflow without the use of additional gradient spoilers and thus shortens the overall TR time.

Petter Dyverfeldt^1,2, Gabriel Acevedo-Bolton¹, Alastair J Martin¹, and David Saloner^1
1Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, ²CMIV and Linköping University, Linköping, Sweden

This study demonstrates the potential of using 3D cine PC-MRI in patient-specific models of atherosclerotic carotid disease to provide detailed information of flow patterns and the spatiotemporal dynamics of turbulence intensity. 45 minutes long high-resolution 3D cine PC-MRI scans were performed in patient-specific models of carotid disease under in-vivo mimicking flow conditions. These high-quality MR data permitted visualization and analysis of potential transarterial pathways for emboli, intrastenotic flow features, and the destabilizing effects of flow deceleration.

Namkug Kim¹, and SeonKyu Lee^2
1Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Seoul, Korea, Republic of, ²Radiology, Tufts University, Boston, MA, United States

Vascular wall shear stress (WSS) is believed to play a critical role in the processes of atherosclerosis. WSS could be used to assess vascular disease initiation and proliferation processes. In this study, we sought to develop a method suitable for time-dependent measurements of WSS in the M1 segment of the MCA with robust lumen segmentation and PVE suppression. To suppress partial volume effects (PVE), bi-exponential curve fitting with wall boundary outliers was performed on velocity profiles. The measured range of WSS is about 4.41~ 6.402 Pa. In addition, the lumen cross-sectional area of MCA and WSS were evaluated at all-time points of the cardiac cycle and their temporal changes including luminal diameter, luminal area change, color-coded WSS on MRI were measured.

Ulrike Wiesspeiner¹, Robert Vollmann², Hannes Deutschmann², Klaus Leber³, and Franz Ebner^4
1Department of Radiology, Medical University of Graz, Graz, Austria, ²Medical University of Graz, ³Neurosurgery, Medical University of Graz, ⁴Neuroradiology, Medical University of Graz

The study compared 3.0 T MRA to conventional (2D or 3D) DSA in the assessment of occlusion, remnant or partial refilling of aneurysms in the presence of coil material. 87 patients underwent 3.0T MRA and DSA, the MR imaging protocol included TOF-MRA (TR/TE/á: 22/ 3.68/ 18°, TA: 04:19 min) and CE-MRA (FLASH 3D TR/TE/á: 3.74/ 1.49/ 20°;GRAPPA, Accel.Factor:2; TA: 00:22 min). There was no false-negative result, but DSA could not confirm 7% of the positive MRA ‘s. 3D MRA has the potential to replace DSA in the assessment of reperfusion of aneurysms even in the presence of coil material.

Sandra Même¹, Mathilde Fauconnier², Marie-Laure Bourrigault², Bernard Ryffel², Valérie Quesniaux², and Jean-Claude Beloeil^1
1CBM CNRS UPR4301, orléans, France, ²IEM CNRS UMR6218, orléans, France

Malaria involves intravascular changes with sequestration of parasitized erythrocytes and host cells in cerebral micro vessels. An animal model infected by Plasmodium berghei ANKA (PbA) has been established to study the pathology. In this model, T-cell activation is required for the development of PbA-induced experimental cerebral malaria. In order to characterize the T cell activation pathway involved, we wanted to adress the role of protein kinase C-Theta (PKC-) from ECM development upon blood stage infection with PbA. In this study, MRA and T2-weighted MRI were used to verify the lack of ischemia and microvascular pathology in PKC- PbA infected mice

Kun Huang¹, David John Mikulis², Frank Silver³, and Andrea Kassner^1
1Medical Imaging, University of Toronto, Toronto, Ontario, Canada, ²Medical Imaging, Toronto Western Hospital, Toronto, Ontario, Canada, ³Neurology, Toronto Western Hospital, Toronto, Ontario, Canada

Blood–brain barrier (BBB) disruption following acute ischemic stroke (AIS) is associated with hemorrhagic transformation. Previous data on BBB disruption after AIS is limited to the first several hours and non-existent in the subacute phase. However, knowledge of BBB dynamics after AIS is important in considering appropriate therapies. We evaluated the time course of BBB disruption in 39 patients over one hour to several days and found that BBB disruption increased between 16-50 hours after onset and decreased thereafter. This may represent transient stabilization of the initial ischemic endothelial BBB injury that stabilizes and reverses as a result of reperfusion.

Jeffry R. Alger^1,2, T J Schaewe³, D. S. Liebeskind³, J. L. Saver³, and C. S. Kidwell^4
1Neurology, Geffen School of Medicine at UCLA, Los Angeles, CA, United States, ²Radiological Sciences, Geffen School of Medicine at UCLA, Los Angeles, CA, United States,³Neurology, Geffen School of Medicine at UCLA, ⁴Neurology, Georgetown University, Washington, DC, United States

The feasibility of half dose (0.05 mmol/kg) DSC microvascular perfusion MRI for stroke evaluation was assessed in normal subjects and by computer simulation under conservative 1.5 T imaging conditions. Results suggest that half dose DSC is feasible. This suggests the possibility reduced gadolinium exposure in routine stroke imaging and clinical trials that use MRI for assessment of stroke therapy.

Alexis Gordon¹, Jackie Leung², Igor Sitartchouk¹, David Mikulis³, and Andrea Kassner^1
1Medical Imaging, University of Toronto, Toronto, Ontario, Canada, ²Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada, ³Medical Imaging, Toronto Western Hospital, Toronto, Ontario, Canada

Hemorrhagic transformation (HT) is a major adverse outcome of acute ischemic stroke. Accurate methods for predicting HT would improve patient care and stratify risk when directing treatment. Quantitative permeability estimates, KPS, are able to predict HT but require an arterial input function and kinetic modelling. Alternatively, semi-quantitative measures such as the initial area under the curve (IAUC) can provide a fast surrogate measure of KPS. However, it is not known what the optimal time interval is to associate AUC with risk of HT. Our study showed that a delayed AUC from 50-140 s is superior to a previously reported IAUC.

Jeffry R. Alger^1,2, T. J. Schaewe³, J J Wang³, D. S. Liebeskind³, Q. Hao³, J. X. Qian², J. L. Saver³, N. Salamon², and . UCLA Stroke Investigators^3
1Neurology, Geffen School of Medicine at UCLA, Los Angeles, CA, United States, ²Radiological Sciences, Geffen School of Medicine at UCLA, ³Neurology, Geffen School of Medicine at UCLA

The study evaluated automatic approaches to selection of arterial input function (AIF) and the value of AIF correction with a measured venous outflow function (VOF). Automated AIF selection using angiographic criteria was moderately more optimal than AIF selection based on dynamic criteria alone. VOF correction was helpful for both types of AIF sampling. Even with these optimal procedures, a variance of more than 40% in the derived most probable CBF measured in normal brain can be anticipated in routine clinically-indicated DSC studies.

Meng Li¹, Jianlin Wu², Yanwei Miao², Zhihong Yang², Waqar Raza¹, Ying Wang³, E. M. Haacke^1,4, and Jian Hu^1
1Department of Radiology, Wayne State University, Detroit, Michigan, United States, ²Department of Radiology, Dalian Medical University, China, People's Republic of,³Department of Computer Science, Northeastern University, Shenyang, China, People's Republic of, ⁴MRI Institute of Biomedical Research, Detroit, Michigan, United States

Oxygenation level is a vital parameter for stoke patients. SWI provides a novel method to measure the oxygenation change of the human brain in vivo in a non-invasive manner. By measuring the phase difference between the veins and surrounding brain tissue in SWI phase imaging, it is possible to estimate the relative changes of oxygenation over time. Our study results demonstrate that the oxygenation saturation level may predict clinical outcomes of the stroke patient, and reveal a dynamic panorama of venous vasculature response to the stroke in a temporal and spatial pattern as well.

Judy R James¹, Asif A Khan², David P Gordy¹, Majid A Khan¹, Juebin Huang², Alexander P Auchus^2,3, and Razvan Buciuc^1,2
1Radiology, University of Mississippi Medical Center, Jackson, MS, United States, ²Neurology, University of Mississippi Medical Center, Jackson, MS, United States,³Neurology, G.V. (Sonny) Montgomery VA Medical Center, Jackson, MS, United States

Diffusion Tensor imaging (DTI), though a well known MR technique to assess degeneration of fiber tracts in stroke affected brains; has received very little attention for its potential clinical significance in conjunction with the neurological scores and deficits. Purpose of this study was to determine if DTI can predict the functional outcome in stroke patients by correlating the degree of motor tract involvement. Our results show that fiber loss in capsular stroke patients has a significant positive correlation with loss in motor functions and less correlation with cognitive functions. DTI and its positive correlation to clinical NIHSS scores can help clinicians in predicting short and /or long term neurological deficits in stroke affected patients.

Rakesh Mullick¹, Uday Patil¹, Sumit K Nath¹, Dattesh D Shanbhag¹, Patrice Hervo², and Catherine Oppenheim^3
1Imaging Technologies, GE Global Research, Bangalore, Karnataka, India, ²GE Healthcare, Buc, France, ³Departments of Radiology and Neurology, Centre Hospitalier Sainte-Anne, Paris, France

The objective of this work was to assess the capability of automated method to compute volume change between DWI image taken in the Acute (Day-0) phase and the follow-up (Day-1). We correlate the qualitative assessment of infarct volume change to the change computed by automated methods to assess the potential use of this measure in a clinical workflow to monitor chronic stroke.

Alex Foerster¹, Achim Gass¹, Rolf Kern¹, Martin Griebe¹, Angelika Alonso¹, Michael G. Hennerici¹, and Kristina Szabo^1
1Department of Neurology, UniversitaetsMedizin Mannheim, Mannheim, Germany

We analyzed stroke morphology on MRI in patients with stroke in the middle cerebral artery territory (MCAT) who received i.v. thrombolysis. Lesion patterns were classified by identifying index lesions in the MCAT and concomitant lesions in the MCAT, other vascular territories or borderzones on DWI and middle cerebral artery (MCA) pathology on MRA. All predefined DWI and MRA patterns occurred in the population. A typical pattern associated with successful recanalisation was small embolic lesions and a normal/strong MCA signal. The classification is based on routinely used MRI sequences and may be useful for a precise stroke pattern description in general.

Ashu Bhasin¹, S Senthil Kumaran², M V Padma¹, Sujata Mohanty³, and Rohit Bhatia^1
1Department of Neurology, All India Institute of Medical Sciences, New Delhi, India, ²Department of N.M.R, All India Institute of Medical Sciences, Delhi, India, ³Stem Cell Facility, All India Institute of Medical Sciences, New Delhi, India

Stroke has a protean impact on disability and is the second largest cause for morbidity in Asian countries. To restore the functionality, stem cells were transplanted intravenously in chronic stroke patients. In this study, the safety, feasibility and efficacy of bone marrow mononuclear and ex vivo expanded mesenchymal stem cells in stroke has been established, along with functional improvement as detected by BOLD activation for motor task.

Guangliang Ding¹, Quan Jiang¹, Lian Li¹, Li Zhang¹, Zhenggang Zhang¹, Qingjiang Li¹, James R Ewing¹, and Michael Chopp^1,2
1Neurology, Henry Ford Hospital, Detroit, Michigan, United States, ²Physics, Oakland University, Rochester, Michigan, United States

This study demonstrated that treatment of embolic stroke with sildenafil in aged rats starting at 24 hours and continuing daily for 7 days significantly augmented angiogenesis and axonal remodeling, accompanied with increased of local blood flow and reduced expansion of the ipsilateral ventricle, up to 6 weeks after stroke, compared to control aged rats. Neurological outcome was significantly improved in sildenafil treated aged rats. However, recovery from ischemic stroke may be age associated. Aged rats subjected to stroke had a higher mortality rate and worse neurological deficits than young rats.

Shujuan J Fan^1,2, Frank Yik Hin Lee^1,2, Matthew Man Hin Cheung^1,2, April Mei Kwan Chow^1,2, Zhongwei W Qiao^1,2, Kevin Chuen Wing Chan^1,2, and Ed X Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, People's Republic of, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China, People's Republic of

Secondary neurodegeneration in substantia nigra (SN) has been commonly observed in ischemic strokes. However, little is known about such degeneration in intracerebral hemorrhage (ICH). In this study, multi-parametric MRI was employed to characterize the evolution of such injuries and understand the underlying pathological changes. The injury was first detected by DTI at day 1 after ICH, and was characterized by dramatic diffusivity decrease¬, elevated T2 relaxation times at day 3, and gradually increased T1W signal intensities. These results suggested that DTI could be utilized for early diagnosis for secondary SN injury, which would be long-lasting and progressive and worth attention.

Shujuan J Fan^1,2, Matthew Man Hin Cheung^1,2, Abby Ying Ding^1,2, Frank Yik Hin Lee^1,2, Zhongwei W Qiao^1,2, Jian Yang³, and Ed X Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, People's Republic of, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China, People's Republic of, ³Medical Imaging Center of the First Affiliated Hospital, School of Medicine of Xi'an Jiaotong University, Xi'an, Shanxi Province, China, People's Republic of

Previous animal MRI studies of intracerebral hemorrhage (ICH) mainly dealt with the changes of the hemorrhage and its surrounding areas, while white matter injury was poorly understood. Clinical studies have demonstrated that DTI metrics of the corticospinal tract (CST) could be utilized to predict the functional outcome of ICH. The present DTI study revealed irreversible Wallerian degeneration in pyramidal tract, as part of CST, within 3 days after experimental ICH. The characterization of longitudinal diffusivity changes of such degeneration could provide a comprehensive understanding of white matter injury after ICH, and further support the utilization of DTI for ICH prognosis.

Edward S. Hui¹, Fang Du¹, Qiang Shen¹, Shiliang Huang¹, and Timothy Q. Duong^1
1Research Imaging Institute, University of Texas Health Science Center San Antonio, San Antonio, Texas, United States

The outcome of stroke treatment relies in large part on reliable staging of ischemic tissue. With the high sensitivity and specificity of conventional DWI in ischemic tissue delineation, additional clinically relevant information regarding ischemic tissue microstructure should be probed using diffusion kurtosis imaging (DKI). The goal of this study was to explore what additional DKI data could offer in ischemic stroke rat during hyperacute and acute phases. The current study shows that MK is a sensitive index of hyperacute ischemic injury, and increases with time from hyperacute to acute phase, offering a valuate tool to better stage ischemic brain injury.

Asamoah Bosomtwi¹, Michael Chopp^2,3, Guang Liang Ding², Li Zhang², Leonard L Howell¹, and Quan Jiang^2
1Yerkes Primate Center, Emory University, Atlanta, GA, United States, ²Neurology, Henry Ford Hospital, ³Physics, Oakland University

We investigated vascular remodeling after stroke and dynamically monitor these changes using MRI microvascular density (MVD), MRI mean vessel size (VSI) and MRI mean segment length (MSL). We demonstrate that MRI parameters can detect the microvascular status of brain tissue and evaluate the efficacy of erythropoietin (EPO) treatment.

Yimin Shen¹, Weili Zheng¹, Yu-Chung N Cheng¹, Yuchuan Ding², Jean Sebastien Raynaud³, and E Mark Haacke^1
1Radiology, Wayne State University, Detroit, MI, United States, ²Neurological Surgery, Wayne State University, Detroit, MI, United States, ³Guerbet, France

Our purpose is to determine if USPIO high resolution SWI at 7T sufficiently aid in visualization of collateral vessels in the penumbral area of lesions in a rat MCAO stroke model. Stroke in rats was induced by a 2-hour right MCAO using an intraluminal filament. MRI scans were performed on no stroke (n=1), stoke no treatment (n=5), stroke with sildenafil treatment rats (n=6) at four time points: baseline, 24h post MCAO, two weeks, four weeks. SWI shows clearly the presence of newly developed vessels near periphery of ischemic core in sildenafil treated severe stroke animals after two-week MCAO but not shows in mild stroke animals.