t.t. liu, fbirn ahm 2006 status of arterial spin labeling for the fbirn thomas t. liu ucsd center...
TRANSCRIPT
T.T. Liu, fBIRN AHM 2006
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
0 1 2 3 4 5 6 7 8
TRIAL
0
6
12
18
24
Δ ( )S Local Units
Drug Fee
0 1 2 3 4 5 6 7 8
TRIAL
0
6
12
18
24
Acetazolamide
Acetazolamide Administration
0 1 2 3 4 5 6 7 8
TRIAL
0
4
8
12
16
20
24
28
32
Δ ( )CBF Local Units
Drug Free
0 1 2 3 4 5 6 7 8
TRIAL
0
4
8
12
16
20
24
28
32
Acetazolamide
Acetazolamide Administration
T.T. Liu, fBIRN AHM 2006
Motivation for Arterial Spin Labeling
T.T. Liu, fBIRN AHM 2006
Motivation for Arterial Spin Labeling
Activation 01020304050607080
BOLD (x10)CBF: Activation CBF: CO2 CMRO2:
Change (%)
0102030405060
BOLD (x10)CBF: Activation CBF: CO2 CMRO2:Activation
Change (%)
HIVNormal
VisualBasal Ganglia
a) Visual and Basal Ganglia Responses
b) Basal Ganglia: HIV vs. Normal
T.T. Liu, fBIRN AHM 2006
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 SitesGE Sites: UCSD, Stanford Siemens Sites: MGH, Univ. Minnesota
Possible Sites for Secondary GroupGE Sites: Duke, BWHSiemens 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 SpiralFOV 220 64x645mm skip 1TR 2.5s TE 3.2msFAIRERTI1/TI2 600/1500Time: 6.5 min
T.T. Liu, fBIRN AHM 2006
Issues and Tasks
1. Need Siemens research agreement for UMINN
2. Limited technical support for ASL available on Siemens side.
Issues
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