Appendix D
Recommended DW-MRI scan protocols

Date: May 21, 2010

Disclaimer: this document contains recommendations for optimal DW-MRI acquisition. We (Brain Innovation BV) are not responsible for any damages caused in any way resulting from following these recommendations.

Sequence

double-refocused single shot EPI reduces eddy current distortions.

Field of View

minimal 240 mm (square)

k-space coverage

symmetrical

Number of Slices

minimum needed to cover entire brain including cerebellum (usually > 55)

Slice orientation

axial

Voxel size

Isotropic, 2.5 x 2.5 x 2.5 minimum recommended

Matrix size

square 96x96, 128x128, etc

Slice gap

0 mm

Angulation

none, could cause mis-calculation of tensors

TR

shortest to accommodate all slices

TE

minimum needed for full acquisition

Zero-filling

No zero-filling or interpolation

Parallel imaging

SENSE (factor 2) or GRAPPA

Diffusion directions

> 6 directions for MD, > 20 directions for FA and fiber tracking, > 80 directions for HARDI applications

b0

1 b0 for every 6-10 diffusion weighted images

b-value

600-1200 s/mm² for DTI, > 2000 for HARDI/q-ball etc

Averages

As many as possible given the scan time. Do not average real-time on the scanner, but save each repetition as a seperate data set.

Supported Raw data formats in BVQX

DICOM, DICOM MOSAIC, PAR/REC, Nifti via Nifticonverter plugin

Sources:

• BIRN Imaging protocols http://nbirn.net/research/morphometry/imaging_protocols.shtm May 21, 2010;
• S. Mori Introduction to Diffusion Tensor Imaging Elsevier 2007;
• ISMRM Diffusion and Perfusion study group mailing list