Hi Yuko,
We use the same Philips scanner. General parameters for fMRI:
Imaging Mode: Single Shot EPI
FOV (mm): 240
RFOV (%): 90
Scan Matrix: 80
Reconstruction: 128
SENSE factor: 2
Thickness (mm): 3.0
Gap (mm): 0.0
Number of slices: 34
TE (ms): 35
Flip angle (deg): 70
TR (ms): 2000
I can provide a .par file with complete acquisition info if you'd like- just don't have access to one from here.
Use 8-channel head coil; more channels (e.g., 16, 32) improve image quality (we are currently testing 32-channel).
fMRI acquisition are typically aligned AC-PC; depending on individual subject anatomy, angling acquisition further away from sinuses (i.e., in sagittal view, increasing angle relative to y plane) helps to reduce artifacts in orbital-frontal caused by oxygen in sinuses.
To maximize retention of acquired voxel dimensions/resolution, data should be obtained from scanner in at least 16-bit (32 better) format (e.g., .par/.rec format- check .par file to ensure data are being written in 16-bit); default dicom is 8-bit, which cannot retain smaller resolution (our acquired dimensions are 1.8 x 1.8 x 3 mm). If you have a research contract with Philips, your MR physicist/engineer should be able to configure the system to write out in nifti, which is optimal as it retains all acquisition information (vs. analyze format) and is required for image analysis using SPM8.
Hope this helps,
Julie
Julie E. McEntee, M.A., C.C.R.P.
Senior Research Program Coordinator
Department of Psychiatry- Neuroimaging
Johns Hopkins University School of Medicine
600 N. Wolfe St./ Phipps 300
Baltimore, MD 21287
Phone: 410-502-0468
Fax: 410-614-3676
----- Original Message -----
From: Yuko <[log in to unmask]>
Date: Monday, February 15, 2010 6:14 pm
Subject: [SPM] How to setup the parameters for orbito-frontal cortex?
To: [log in to unmask]
> Dear all
>
> I posted same message before.
> I don't want to bother you again.
> But I can't setup parameters for orbito-frontal cortex.
> Our MRI scanner is 'Intera Achieva 3.0Tesla Quasar Dual, Philips'
>
> Could any one give me some suggestions to regarding set up the scanner
> parameters to minimize the lose of signals?
>
> Any idea would be highly appreciated.
>
> Thanks
|