Image metric-based correction (autofocusing) of motion artifacts in high-resolution trabecular bone imaging
✍ Scribed by Wei Lin; Glenn A. Ladinsky; Felix W. Wehrli; Hee Kwon Song
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 538 KB
- Volume
- 26
- Category
- Article
- ISSN
- 1053-1807
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✦ Synopsis
Abstract
Purpose
To evaluate the performance of the autofocusing (AF) motion correction technique in high‐resolution trabecular bone imaging where image signal‐to noise ratio (SNR) is limited.
Materials and Methods
Raw data from 26 clinical three‐dimensional (3D) wrist exams were motion corrected using AF for both in‐plane rotation and translation. Changes in image metrics (a measurement of image sharpness) and structural parameters subsequently computed, were used to gauge the performance of the AF algorithm, and comparisons were made with translation‐only navigator‐corrected results.
Results
On average, AF generated images with higher image sharpness compared to the navigator echo technique. The average normalized gradient squared (NGS) metric improved by 0.40%, 0.73%, and 0.84%, respectively, following translation‐only navigator, translation‐only AF and combined rotation/translation AF. For all structural parameters, the rotation/translation AF resulted in an approximately two‐fold greater change compared to the navigator technique.
Conclusion
The data provide evidence that errors from subtle translational and rotational motion in the structural parameters in high‐resolution trabecular bone images are alleviated by AF and that the resulting improvements are superior to translation‐only 2D navigator correction. J. Magn. Reson. Imaging 2007;26:191–197. © 2007 Wiley‐Liss, Inc.