| Multiparametric Approaches to Clinical Stroke Imaging |
|
Monday 20 April 2009 |
| Room 311 |
11:00-13:00 |
Moderators: |
Jeffry R. Alger and Lawrence Latour |
|
|
| |
|
11:00 |
32. |
Comparison of ASL and PWI Perfusion in Stroke
Patients |
|
|
|
Esben Thade Petersen1,2, Tchoyoson
C.C. Lim2, N Venketasubramanian2,
Xavier Golay2,3
1Center of Functionally Integrative
Neuroscience, University of Aarhus, Aarhus, Denmark;
2National Neuroscience Institute,
Singapore; 3Institute of Neurology,
University College London, UK |
| |
|
One
obvious problem of ASL in stroke imaging is the
limited duration of the label, which makes it
arguable whether ASL will have a chance as compared
to PWI when it comes to penumbra estimation and
subsequent risk-benefit weighting of possible
intervention. In this work we show that ASL acquired
at multiple time-points provides similar information
to PWI in the affected areas. In addition, ASL can
probe the existence of collateral perfusion and
combined they could potentially be valuable in this
risk assessment. However it still remains to future
studies of hyperacute stroke to tell whether ASL can
prove sufficient. |
| |
|
|
|
11:12 |
33. |
3
T Pulsed Arterial Spin Labeling MRI Reveals
Perfusion Deficits in Patients with Minor Stroke or
Transient Ischaemic Attack |
|
|
|
Bradley J. MacIntosh1,
Alistair C. Lindsay2, Ilias Kylintireas2,
Justin M. Lee2, Matthew D. Robson2,
James Kennedy3, Robin P. Choudhury2,
Peter Jezzard1
1Clinical Neurology, FMRIB Centre, Oxford,
Oxfordshire, UK; 2Department of
Cardiovascular Medicine, John Radcliffe; 3Acute
Stroke Programme, Nuffield Department of Clinical
Medicine, John Radcliffe |
|
|
|
Dynamic susceptibility
contrast (DSC) is the clinical-standard perfusion
MRI technique for acute ischaemic stroke. Arterial
spin labeling (ASL) is a complementary non-invasive
perfusion MRI technique and has demonstrated promise
in a limited number of clinical ASL studies. The
purpose of the current study is test the feasibility
of acute multiple-inflow pulsed ASL in a group of
minor stroke patients. An automated clustering
technique is used to visualise voxels where the
arterial transit times are delayed and produce low
CBF levels. We argue that ASL has the sensitivity to
detect perfusion deficits even in patients that have
low impairment. |
|
|
|
|
|
11:24 |
34. |
Comparison of CBF Measurement by ASL and SPECT in
Patients with Internal Carotid Artery Stenosis |
|
|
|
Yoshito Uchihashi1,
Kohkichi Hosoda1, Ivan Zimine2,
Atsushi Fujita1, Satoshi Inoue1,
Hideo Aihara1, Hideaki Kawamitsu3,
Nobukazu Aoyama3, Hajime Aoki3,
Masahiko Fujii3, Eiji Kohmura1
1Dept. of OrganTherapeutics, Neurosurgery,
Kobe University graduate school of Medicine, Kobe,
Hyogo, Japan; 2Philips Healthcare Japan;
3Dept. of Radiology, Kobe University
graduate school of Medicine, Kobe, Hyogo, Japan |
|
|
|
ASL tecknique provide
quantative CBF measurement of brain perfusion in
good agreement with SPECT which is already
established method for making decision for
Neurosurgical interventions. |
| |
|
|
|
11:36 |
35. |
Predictive Value of Structural Integrity of Affected
Corticospinal Tracts in Motor Function Outcome of
Affected Upper Extremities in Patients with
Subcortical Ischemic Stroke: A Diffusion Spectrum
Imaging Tractography Study |
| |
|
Miao-Chi Lo1,
Yi-Hsin Ko2, Pei-Fang Tang2,3,
Wen-Yih Isaac Tseng1,4
1Center for Optoetectronic Biomedicine,
National Taiwan University College of Medicine,
Taipei, Taiwan; 2School and Graduate
Institute of Physical Therapy, National Taiwan
University College of Medicine, Taipei, Taiwan;
3Physical Therapy Center, National Taiwan
University Hospital, Taipei, Taiwan; 4Department
of Medical Imaging, National Taiwan University
Hospital, Taipei, Taiwan |
| |
|
We used diffusion
spectrum imaging (DSI) tractography to investigate
whether the structural integrity of the
corticospinal tract (CST) of the affected upper
extremity can predict the motor outcome in patients
with subcortical ischemic stroke. The entire CST of
each subject was reconstructed and the mean
generalized fractional anisotropy (GFA) values of
the tract were analyzed. The tract-specific
quantitative analysis of the relative GFA (rGFA)
values of different segments of bilateral CSTs was
derived to indicate the structural integrity of CST
in various segments. The rGFA values in the IC
segment of CST at D30 were highly correlated with
the FMA-UE scores at D180 (N = 7, r = -.802, p =
.030). In conclusion, the structural integrity of
the affected CST early after stroke appears to have
predictive value for late motor recovery. |
| |
|
|
|
11:48 |
36. |
Predicting Tissue Outcome in Acute Ischemic Stroke
Using Projection Pursuit Regression |
|
|
|
Kartheeban Nagenthiraja1, Kristjana Yr
Jonsdottir1, Leif Østergaard1,
Kim Mouridsen1
1Dept. of Neuroradiology, Århus University
Hospital, CFIN, Århus C, Denmark |
|
|
|
We have presented a
flexible procedure for predicting final tissue
outcome combining a dimension reduction method with
efficient regression modeling of the resulting
low-dimensional projections using smooth non-linear
ridge functions. Increase in performance was
observed for PPR notably in single-subject models,
while performance in data pooled across patients was
similar to LR, possibly owing to increased
heterogeneity (reperfusion status, time of scan). We
speculate that PPR in combination with techniques
for identifying homogenous patient subgroups could
further improve quantification of regional risk of
infarct progression. |
| |
|
|
|
12:00 |
37. |
ADC Values in the Corticospinal Tract at the Acute
Stage Can Help Predict Stroke Outcome |
|
|
|
Charlotte Rosso1,2,
Olivier Colliot2, Christine Delmaire3,
Romain Valabregue3, Sylvain Baillet2,
Sophie Crozier1, Didier Dormont2,4,
Yves Samson1, Stéphane Lehéricy3,4
1Stroke Center, Pitie Salpetriere
Hospital, University Pierre and Marie Curie, Paris,
France; 2Cognitive neuroscience and Brain
Imaging Laboratory, CNRS-UPR 640 LENA, Pitie
Salpetriere Hospital, University Pierre and Marie
Curie, Paris, France; 3Center for
NeuroImaging Research, Pitie Salpetriere Hospital,
University Pierre and Marie Curie, Paris, France;
4Department of Neuroradiology, Pitie
Salpetriere Hospital, University Pierre and Marie
Curie, Paris, France |
|
|
|
We used DWI and ADC maps
acquired in the first six hours of stroke onset-H6
and the day after-D1 to predict ischemic stroke
outcome at three months in 76 patients. Normalized
ADC maps were analyzed for differences between
patients with good and poor outcome. ADC values in
the corticospinal tract were measured in both groups
and used to classify patients according to outcome.
ADC values were lower in the CST of patients with
poor than patients with good outcomes at both
examinations (p<0.05). ADC values in the “damaged”
CST predicted outcome with 65% accuracy at H6 and
71% at D1. |
|
|
|
|
|
12:12 |
38. |
Identifying Stroke Patients Most Likely to Benefit
from Reperfusion Therapy Using Acute MRI |
| |
|
Ona Wu1,2,
Søren Christensen2, Niels Hjort2,
Anders Neumann2, A Gregory Sorensen1,
Gotz Thomalla3, Jens Fiehler4,
Thomas Kucinski4, Joachim Rother3,
Leif Østergaard2
1Athinoula A. Martinos Center for Biomedical
Imaging, Massachusetts General Hospital,
Charlestown, MA, USA; 2Center for
Functionally Integrative Neuroscience, Aarhus
University Hospital, Aarhus, Denmark; 3Neurology,
University Medical Center Hamburg-Eppendorf,
Hamburg, Germany; 4Neuroradiology,
University Medical Center Hamburg-Eppendorf,
Hamburg, Germany |
| |
|
Identification of
patients most likely to benefit from reperfusion
therapy is a key question in the management of acute
stroke patients. Algorithms combining DWI/PWI for
predicting infarction in stroke patients (< 6h) were
trained on patients receiving standard non-thrombolytic
treatment and then applied to patients who received
thrombolysis. Predicted lesion volumes were
significantly higher in patients without early
reperfusion compared to patients who did reperfuse.
Our results show that for patients given
thrombolytic therapy, the likelihood of reperfusion
depends on the degree and extent of the ischemic
injury at the time of treatment, which we measured
using multiparametric predictive algorithms. |
| |
|
|
|
12:24 |
39. |
Oxygen Metabolic Index as a Predictor of Tissue
Viability in Acute Ischemic Stroke Patients |
| |
|
Hongyu An1, Andria L. Ford2,
Katie Vo3, William J. Powers4,
Jin-Moo Lee2, Weili Lin1
1Radiology, University of North Carolina at
Chapel Hill, Chapel Hill, NC, USA; 2Neurology,
Washington University in St. Louis, St. Louis, MO,
USA; 3Radiology, Washington University in
St. Louis, St. Louis, MO, USA; 4Neurology,
University of North Carolina at Chapel Hill, Chapel
Hill, NC, USA |
| |
|
We have utilized MR_OMI
to assess the cerebral oxygen metabolic activity
sequentially (<3.5 hours and at 6 hours) in
hyper-acute stroke patients. By using the
reperfusion and final infarct status, tissue with
different outcomes (dead or alive) were examined in
regions either with or without reperfusion. We found
that dead tissue had much lower MR_OMI values than
alive tissue independent of reperfusion status,
suggesting that MR_OMI is capable of predicting
tissue outcome in hyper-acute ischemic stroke. |
| |
|
|
|
12:36 |
40. |
Diffusion Time Dependent Kurtosis Maps Visualize
Ischemic Lesions in Stroke Patients |
|
|
|
Jimmy Lätt1,
Danielle van Westen1, Markus Nilsson2,
Ronnie Wirestam2, Freddy Ståhlberg2,3,
Stig Holtås1,3, Sara Brockstedt1,2
1MR Department, Center for Medical Imaging and
Physiology, Lund University Hospital, Lund, Sweden;
2Department of Medical Radiation Physics,
Lund University, Lund, Sweden; 3Department
of Diagnostic Radiology, Lund University, Lund,
Sweden |
| |
|
Diffusion time
dependence of the diffusion weighted signal for high
b-values in ischemic stroke lesions was recently
reported, allowing for the extraction of more
information on the tissue microstructure. Here, we
express the diffusion time dependence as a change
kurtosis, where kurtosis reflects the degree of
deviation from free diffusion. The changes in
kurtosis for different diffusion times were
calculated for nine ischemic stroke patients,
examined at a 3T clinical scanner. The change in
kurtosis successfully visualized the lesions.
Changes in kurtosis are suggested to reflect changes
in cell sizes as well as in cell physiology
(cellular membrane functionality). |
| |
|
|
|
12:48 |
41. |
Functional MRI Exploration of Visuospatial Attention
in Acute Neglect and Non-Neglect Stroke Patients |
|
|
|
Roza M. Umarova1, Dorothee Saur2,
Christoph Kaller1, Magnus-Sebastian Vry1,
Volkmar Glauche2, Irina Mader3,
Cornelius Weiller1
1Department of Neurology, University Medical
Center , Freiburg, Germany; 2Department
of Neurology, University Medical Center, Freiburg,
Germany; 3Department of Neuroradilogy,
University Medical Center , Freiburg, Germany |
|
|
|
We aimed to explore what
distinguishes patients with and without neglect
after acute stroke in the right hemisphere using
fMRI with visuospatial attention task. Patients
without neglect showed spared function of key
attentional centers in the left hemisphere and post-Rolandic
structures in the right hemisphere. Neglect patients
presented a down-regulation in most of attentional
centers, while the infrequent left targets detection
correlated with involvement of the left hemisphere
structures. Thus, the spared function of the
attention relevant regions in non-neglect patients
enabled the modulation of the right primary and
association visual areas with a subsequent left
targets detection. |
|
|
|
|
|