Transcript Status of Arterial Spin Labeling for the fBIRN Thomas T. Liu

Status of Arterial Spin Labeling for the fBIRN
Thomas T. Liu
UCSD Center for Functional MRI
T.T. Liu, fBIRN AHM 2006
Motivation for Arterial Spin Labeling
T.T. Liu, fBIRN AHM 2006
Motivation for Arterial Spin Labeling
T.T. Liu, fBIRN AHM 2006
Motivation for Arterial Spin Labeling
Acetazolamide
S (Local Units)
24
Drug Fee
18
12
6
Acetazolamide Administration
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TRIAL
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Acetazolamide
Drug Free
CBF (Local Units)
24
Acetazolamide Administration
20
16
12
8
4
0
0
T.T. Liu, fBIRN AHM 2006
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TRIAL
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Motivation for Arterial Spin Labeling
T.T. Liu, fBIRN AHM 2006
Motivation for Arterial Spin Labeling
80
a) Vis ual and Bas al Ganglia Respons es
Change (%)
70
Visual
Basal Ganglia
60
50
40
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20
10
0
BOLD (x10) CBF: Activation
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CBF: CO 2
b) Bas al Ganglia: HIVvs. Norm al
50
Change (%)
CMRO 2:
Activation
HIV
Normal
40
30
20
10
0
BOLD (x10)
T.T. Liu, fBIRN AHM 2006
CBF: Activation
CBF: CO 2
CMRO 2:
Activation
Proposed Aims
Calibration Aim 3. We will develop and incorporate into the FBIRN
imaging protocol a calibration method that adjusts measured BOLD
signal based on baseline CBF measured using arterial spin labeling
(ASL).
Subaim 3.1. Develop, test, and deploy an ASL sequence to the FBIRN
sites.
Subaim 3.2. Develop and test a calibration algorithm that incorporates
baseline CBF measures into the BOLD signal calculation process.
Subaim 3.3. Develop, test, and deploy software implementing this
calibration algorithm.
Subaim 3.4. Incorporate the calibration method into the FBIRN imaging
protocol
T.T. Liu, fBIRN AHM 2006
Proposed Timeline
Year 1: Review available PASL versions and decide on a standard version for
FBIRN. Develop an implementation of this standard version on main FBIRN
scanner platforms (GE, Siemens).
Year 2: Across Development sites, collect data at a range of inversion times to
determine transit delays and temporal bolus width (10 patients and 10 controls).
Year 3: Using the optimized sequence parameters, measure baseline CBF and
the BOLD sensorimotor task in 10 schizophrenic patients and controls at a
single site (Series C Step 1). Use these data to develop and test algorithms
incorporating baseline CBF measures into the BOLD signal calculation process.
Verify across GE and Siemens platforms using retest of the same subjects.
Year 4: Further test and refine the calibration method. Develop and field test
calibration software. Deploy software and sequences at all FBIRN sites. Collect
and process test data at FBIRN sites to verify correct installation and
implementation.
Year 4.5 and 5: Integrate PASL calibration procedure into FBIRN imaging
protocol and use as part of data analysis. Work to make compatible with the
BIRN processing pipeline.
T.T. Liu, fBIRN AHM 2006
Participating Sites
Development Sites
GE Sites: UCSD, Stanford
Siemens Sites: MGH, Univ. Minnesota
Possible Sites for Secondary Group
GE Sites: Duke, BWH
Siemens Sites: UCI, Yale, Iowa, UNM, UCLA
T.T. Liu, fBIRN AHM 2006
UPENN Sequence (at MGH)
Single Shot EPI
UCSD Sequence
Single Shot Spiral
FAIRER; TI1/TI2 = 700/1500; 5 mm skip 1; FOV 225mm,
matrix 64x64 ; TR 2000ms; 130 reps
T.T. Liu, fBIRN AHM 2006
UCSD Sequence
Multi-Shot Spiral
FOV 220 64x64
5mm skip 1
TR 2.5s TE 3.2ms
FAIRER
TI1/TI2 600/1500
Time: 6.5 min
T.T. Liu, fBIRN AHM 2006
Issues and Tasks
Issues
1. Need Siemens research agreement for UMINN
2. Limited technical support for ASL available on Siemens
side.
Tasks
1. Deploy and test baseline ASL protocol at UCSD, Stanford,
UMINN, and MGH. Target coverage: 20 slices; 4 mm skip 1.
2. Decide on whether to include functional ASL protocol
T.T. Liu, fBIRN AHM 2006
UPENN Sequence (at MGH)
Single Shot EPI (6/8 Partial
Fourier) TE 11ms
UCSD Sequence
Single Shot Spiral;
TE 3.2ms
FAIRER; TI1/TI2 = 700/1500; 5 mm skip 1; FOV 225mm,
matrix 64x64 ; TR 2000ms; 130 reps
T.T. Liu, fBIRN AHM 2006