13:30 |
0712.
|
Whole Brain Arterial
Transit Times in the Elderly Estimated Using Arterial Spin
Labeling
Henri J.M.M. Mutsaerts1, Edo Richard2,
Dennis F.R. Heijtel1, Charles B.L.M. Majoie1,
and Aart J. Nederveen1
1Radiology, Academic Medical Center,
Amsterdam, Netherlands, 2Neurology,
Academic Medical Center, Amsterdam, Netherlands
Transit time measurements may not only improve the
quantification of arterial spin labeling but also
provide valuable diagnostic information that is
unavailable with cerebral blood flow measurements alone.
This study estimates micro-vascular arterial transit
time by Flow-Encoding Arterial Spin Tagging (FEAST) in a
large sample of community-dwelling elderly. The measured
transit times show a consistent spatial pattern and
depend on age and gender. If no transit time maps are
available, our linear regression parameters provide an
alternative to a fixed transit time.
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13:42 |
0713.
|
Changes in Cerebral Blood
Flow and Vasoreactivity to CO2 Measured by Arterial Spin
Labeling After 6 Days at 4,350 M
Marjorie Villien1, Pierre Bouzat1,
Thomas Rupp2, Paul Robach3,
Laurent Lamalle4, Irène Troprès4,
François Estève5, Alexandre Krainik6,
Patrick Levy2, Jan M. Warnking1,
and Samuel Verges2
1Grenoble Institut of Neurosciences, INSERM,
Grenoble, France, 2Laboratoire
HP2, INSERM, Echirolles, France, 3Ecole
Nationale de Ski et d’Alpinisme, Chamonix, France, 4SFR1,
Université Joseph Fourier, Grenoble, France, 5ESRF,
Grenoble, France, 6Clinique
universitaire de neuroradiologie et d'IRM, CHU Grenoble,
Grenoble, France
We assess the effects of a sojourn of 6 days at 4,350m
on cerebral perfusion and on cerebrovascular reactivity
to CO2 using ASL at sea level and transcranial Doppler
ultrasound at altitude. We demonstrate that high
altitude exposure significantly decreases vasoreactivity
to CO2. The increase in CBF observed after several days
at high altitude is not only the consequence of the
vasodilating effect of hypoxia but probably involves
other mechanisms such as changes in cerebral
autoregulation and angiogenesis. This study is the first
to measure cerebral perfusion and vasoreactivity with
ASL after a prolonged stay at high altitude.
|
13:54 |
0714.
|
Decreased Retinal and
Choroidal Blood Flow by MRI Is Correlated with
Electroretinography in Retinitis Pigmentosa
Yi Zhang1, Joseph Harrison2, Oscar
San Emeterio Nateras1, Steven Chalfin2,
and Timothy O. Duong1,2
1Radiology, University of Texas Health
Science Center at San Antonio, San Antonio, TX, United
States, 2Ophthalmology,
University of Texas Health Science Center at San
Antonio, San Antonio, TX, United States
Retinitis pigmentosa (RP) is a heterogeneous hereditary
disease characterized by photoreceptor degeneration and
retinal pigment deposits. Altered ocular blood
circulation has been implicated in the degenerative
process and/or the pathogenesis of RP. This study
demonstrates a novel MRI approach to study the
circulatory changes associated with RP in unanesthetized
humans. MRI indicates significantly reduced blood flow
(BF) in RP retina with a strong link to its suppressed
electroretinogram responses.
|
14:06 |
0715.
|
Multi-Site Evaluations of a
TRUST MRI Technique to Measure Brain Oxygenation
Peiying Liu1, Ivan E. Dimitrov1,2,
Trevor Andrews2,3, David E. Crane4,
Jacinda K. Dariotis5, John Desmond6,
Julie Dumas3, Guillaume Gilbert2,
Anand Kumar7, Jean-Maxime Leroux8,
Bradley MacIntosh4,9, Shaolin Yang7,
Guanghua Xiao10, and Hanzhang Lu1
1Advanced Imaging Research Center, University
of Texas Southwestern Medical Center, Dallas, Texas,
United States, 2Philips
Medical Systems, Cleveland, Ohio, United States, 3University
of Vermont College of Medicine, Burlington, Vermont,
United States, 4Heart
and Stroke Foundation Centre for Stroke Recovery,
Sunnybrook Research Institute, Toronto, Ontario, Canada,5Department
of Population, Family, and Reproductive Health, Johns
Hopkins University, Baltimore, Maryland, United States, 6Department
of Neurology, Johns Hopkins University, Baltimore,
Maryland, United States, 7Department
of Psychiatry, University of Illinois at Chicago,
Chicago, Illinois, United States, 8Department
of Radiology, Hospital of the University of Montreal,
Montreal, Quebec, Canada, 9Department
of Medical Biophysics, University of Toronto, Toronto,
Ontario, Canada, 10Department
of Clinical Sciences, University of Texas Southwestern
Medical Center, Dallas, Texas, United States
Venous blood oxygenation (Yv) is critical for the
quantification of CMRO2, a key biomarker for brain
tissue viability and functionality. However,
non-invasive quantification of Yv has proved to be
challenging. Recently, a
T2-Relaxation-Under-Spin-Tagging (TRUST) MRI technique
was developed to measure global Yv in the superior
sagittal sinus. In this work, we evaluated the
applicability and reliability of TRUST in a multi-site
setting. We compared Yv values (i.e. accuracy) and
standard errors of Yv estimation (i.e. precision) across
six imaging centers, and showed that the TRUST sequence
can be effectively transferred and performed on a
standard 3T scanner at remote sites.
|
14:18 |
0716. |
Minimizing the Influence of
Blood Volume Fraction on Other Pharmacokinetic Parameters in
DCE-MRI
Xin Li1, Jeffrey M. Njus1, Seymur
Gahramanov2, Csanad G. Várallyay2,
John W. Grinstead3, Charles S. Springer, Jr.1,
Edward A. Neuwelt2, and William D. Rooney1
1Advanced Imaging Research Center, Oregon
Health & Science University, Portland, Oregon, United
States, 2Department
of Neurology, Oregon Health & Science University,
Portland, Oregon, United States, 3Siemens
Healthcare, Portland, Oregon, United States
For DCE-MRI, it is possible to obtain consistent Ktrans (CR
transfer constant) and ve (extracellular,
extravascular volume fraction) values whether
incorporating vb (blood
volume fraction) or not into DCE-MRI modeling. This
often requires minimizing the influence of vb in
DCE-MRI data time-courses.
|
14:30 |
0717. |
Prediction of Response to
Chemotherapy in Patients with Osteosarcoma and Ewing’s
Sarcoma
Louisa Bokacheva1, Ya Wang1, Wei
Huang2, David M. Panicek3, and
Jason A. Koutcher1,3
1Department of Medical Physics, Memorial
Sloan-Kettering Cancer Center, New York, NY, United
States, 2Advanced
Imaging Research Center, Oregon Health & Science
University, Portland, OR, United States, 3Department
of Radiology, Memorial Sloan-Kettering Cancer Center,
New York, NY, United States
DCE MRI was performed in 34 patients with osteosarcoma
and Ewing's sarcoma before, during and after neoadjuvant
chemotherapy. Patients underwent surgery with
histological assessment of necrosis or radiation therapy
and were followed up clinically for up to six years.
Voxel parameters were derived from DCE MRI data using
linearized form of the Tofts model and population-based
arterial input function. The mean tumor Ktrans decreased
significantly at the time of the third MRI session
relative to baseline. Both the mean Ktrans value
and percent decrease relative to baseline were
predictive of histological response, but did not appear
to predict survival.
|
14:42 |
0718. |
Differentiation of Myeloma
and Metastatic Cancer in the Spine Using Dynamic Contrast
Enhanced MRI
Ning Lang1, Min-Ying Su2, Hon J.
Yu2, Muqing Lin2, and Huishu Yuan1
1Department of Radiology, Peking University
Third Hospital, Beijing, China, 2Center
for Functional Onco-Imaging, Department of Radiological
Sciences, University of California, Irvine, CA, United
States
DCE-MRI was performed to differentiate between myelomas
and metastatic cancers in the spine. The peak signal
enhancement percentage (SE%), the steepest wash-in SE%,
and the wash-out SE%, were calculated. The
two-compartmental pharmacokinetic model was used to
obtain Ktrans and kep. The myeloma group had a higher
peak SE%, a higher wash-in and wash-out SE%, and also a
higher Ktrans and kep. The ROC show that the AUC was
0.798 for Ktrans, 0.864 for kep, and 0.919 for combined
Ktrans and kep. The results show that DCE-MRI may
provide additional information for making differential
diagnosis of spinal tumors.
|
14:54 |
0719.
|
Initial Clinical
Application of Simultaneous MR Angiography and Perfusion (MRAP)
in Peripheral Arterial Disease
Katherine L. Wright1, Arash Aghel2,
Nicole Seiberlich1, Mark A. Griswold1,3,
Anne Hamik2, and Vikas Gulani1,4
1Biomedical Engineering, Case Western Reserve
University, Cleveland, Ohio, United States, 2Case
Cardiovascular Research Institute, Case Western Reserve
Univ. and University Hospitals, Cleveland, Ohio, United
States, 3Radiology,
University Hospitals Case Medical Center, Cleveland,
Ohio, United States, 4Radiology,
Case Western Reserve University, Cleveland, Ohio, United
States
Complete evaluation of both large and small vessels
would typically require two separate contrast enhanced
acquisitions: MR angiography and dynamic contrast
enhanced (DCE) MRI. MRAP (MR Angiography and Perfusion)
is a technique that allows for simultaneous acquisition
of both these exams by using an optimized, 3D,
time-resolved contrast-enhanced acquisition with high
spatial/temporal resolution. This preliminary study
applies MRAP to the clinical evaluation of peripheral
arterial disease (PAD). DCE-MRI perfusion measurements
from various muscles in the leg were correlated to ankle
brachial index (ABI) data to evaluate the use of MRAP in
PAD.
|
15:06 |
0720. |
Preliminary Analysis of
Arterial Input Function Derived from Dynamic Contrast
Enhanced MRI in Children with Cancer
Keiko Miyazaki1, Matthew R. Orton1,
David John Collins1, James A. d'Arcy1,
Toni Wallace2, Lucas Moreno3,
Andrew Pearson3, Stergios Zacharoulis3,
Martin O. Leach1, and Dow-Mu Koh2
1CR-UK and EPSRC Cancer Imaging Centre, The
Institute of Cancer Research, Sutton, Surrey, United
Kingdom, 2Department
of Diagnostic Radiology, The Royal Marsden NHS
Foundation Trust, Sutton, Surrey, United Kingdom, 3Department
of Paediatric Oncology, The Royal Marsden NHS Foundation
Trust, Sutton, Surrey, United Kingdom
The aim of this study is to investigate the feasibility
and challenges of obtaining arterial input functions
from paediatric DCE-MRI studies. Preliminary analysis of
AIFs obtained from paediatric DCE-MRI data have shown it
is possible to obtain consistent AIFs using a power
injector. Inconsistencies in hand-injected AIFs found in
this study have highlighted the need to optimize modes
of contrast agent delivery through central lines. This
is an ongoing study whereby further data will continue
to be acquired in order to build a more representative
paediatric population AIF that would enable quantitative
DCE-MRI data analyses in paediatric clinical trial
settings.
|
15:18 |
0721. |
Dynamic Contrast-Enhanced
Magnetic Resonance Imaging Enables Personalized Anti-EMMPRIN
Therapy for Pancreatic Cancer
Hyunki Kim1, Christopher Rigell1,
Guihua Zhai1, Kyle Lee1, Sharon
Samuel1, Amber Martin1, Timothy
Beasley1, Long Shan Li2, David
Boothman2, and Kurt Zinn1
1University of Alabama at Birmingham,
Birmingham, AL, United States, 2Radiation
Oncology, UT Southwestern Medical Center, Dallas, TX,
United States
Anti-EMMPRIN monotherapy has demonstrated strong
anti-tumor effect via preventing tumor-cell invasion and
neovascularization. However, care must be taken when
applying anti-EMMPRIN antibody in combination with
another small-molecule chemotherapeutic agent like
gemcitabine, because the antiangiogenic effect of anti-EMMPRIN
antibody may excessively decrease the tumor vasculature
for hypovascular tumors, reducing the tumor delivery of
the chemotherapeutic agent while increasing tumor
hypoxia. In this study, differential therapeutic
efficacy of anti-EMMPRIN antibody combined with
non-targeting small-molecule chemotherapy drugs was
confirmed according to tumor vascularity, and a clinical
protocol to enable personalized treatment of pancreatic
cancer patients based on DCE-MRI was suggested.
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