Dynamic field mapping and distortion correction for fMRI

Ning Xu; J. Michael Fitzpatrick

doi:10.1117/12.709509

5 March 2007 Dynamic field mapping and distortion correction for fMRI

Ning Xu, J. Michael Fitzpatrick

Proceedings Volume 6512, Medical Imaging 2007: Image Processing; 65121M (2007) https://doi.org/10.1117/12.709509
Event: Medical Imaging, 2007, San Diego, CA, United States

Abstract

Echo planar images (EPI) suffer from geometric distortions caused by static-field inhomogeneity. Correction techniques have been suggested based on field maps obtained before or after the EPI acquisition. However, when a relatively long time series of images is required, as in fMRI studies, the inhomogeneity varies from image to image because of gross motion and physiological activity such as respiration and cardiac motion. It is not ideal to approximate the varying maps of field inhomogeneity by means of one map. To overcome this limitation, multiple field maps are desirable for correcting the distortions that are dynamically changing. Some groups have explored the possibility of acquiring multiple field maps, but either the increased scan time is not affordable for most fMRI studies or the field map acquisition is embedded in EPI pulse sequence, which produces a map of insufficient resolution to support a complete distortion correction. In this paper, we propose a dynamic field mapping technique that uses a single reference image and a single corresponding acquired field map and the phase information extracted from the complex image data of each EPI image in the time series. From this information, a separate field map is then derived individually for each EPI image. The derived field maps are then used for distortion correction. This approach, which is particularly suitable for fMRI studies, can correct for image distortion that varies dynamically without sacrificing temporal resolution. We validate this technique using simulated data, and the experimental results show improved performance in comparison to correction using a single field map.

Citation Download Citation

Ning Xu and J. Michael Fitzpatrick "Dynamic field mapping and distortion correction for fMRI", Proc. SPIE 6512, Medical Imaging 2007: Image Processing, 65121M (5 March 2007); https://doi.org/10.1117/12.709509

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
11 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Distortion

Functional magnetic resonance imaging

Head

Signal to noise ratio

Image processing

Statistical analysis

Computer programming

Show All Keywords

Keywords/Phrases

Search In:

Publication Years