Format

Send to

Choose Destination
See comment in PubMed Commons below
Skeletal Radiol. 2009 Jan;38(1):51-9. doi: 10.1007/s00256-008-0577-6. Epub 2008 Sep 5.

Diffusion tensor imaging and fiber tractography of the median nerve at 1.5T: optimization of b value.

Author information

1
Division of Musculoskeletal Imaging, Department of Medical Imaging, Mount Sinai Hospital and the University Health Network, University of Toronto, 600 University Ave, Toronto, Ontario, Canada, M5G 1X5. gustav@andreisek.de

Abstract

OBJECTIVE:

The objective of this study was to systematically assess the optimal b value for diffusion tensor imaging and fiber tractography of the median nerve at 1.5 T.

MATERIALS AND METHODS:

This is a prospective study which was carried out with institutional review board approval and written informed consent from the study subjects. Fifteen healthy volunteers (seven men, eight women; mean age, 31.2 years) underwent diffusion tensor imaging of the wrist. A single-shot spin-echo-based echo-planar imaging sequence (TR/TE, 7000/103 ms) was performed in each subject at eight different b values ranging from 325 to 1,550 s/mm(2). Number and length of reconstructed fiber tracts, fiber density index (FDi), fractional anisotropy (FA), and apparent diffusion coefficient (ADC) were calculated for the median nerve. Signal-to-noise ratio (SNR) was also calculated for each acquisition. The overall image quality was assessed by two readers in consensus by ranking representative fiber tract images for each subject using a scale range from 1 to 8 (1 = best to 8 = worst image quality).

RESULTS:

Longest fibers were observed for b values between 675 and 1,025 s/mm(2). Maximum FDi was found at b values of 1,025 s/mm(2). FA was between 0.5 and 0.6 for all b values. ADC gradually decreased from 1.44 x 10(-3) to 0.92 x 10(-3) mm(2)/s with increasing b values. Maximum SNR +/- standard deviation (175.4 +/- 72.6) was observed at the lowest b value and decreased with increasing b values. SNR at b values of 1,025 s/mm(2) was 48.5% of the maximum SNR. Optimal fiber tract image quality was found for b values of 1,025 s/mm(2).

CONCLUSIONS:

The optimal b value for diffusion tensor imaging and fiber tractography of the median nerve at 1.5 T was 1,025 s/mm(2).

PMID:
18773203
DOI:
10.1007/s00256-008-0577-6
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Springer
    Loading ...
    Support Center