Adaptive ultrasound imaging of the lumbar spine for guidance of epidural anesthesia

Received 10 January 2009; received in revised form 7 May 2009; accepted 4 June 2009.

Abstract

Ultrasound imaging can help in choosing the needle trajectory for epidural anesthesia but anatomical features are not always clear. Spatial compounding can emphasize structures; however, features in the beam-steered images are not aligned due to varying speeds of sound. A non-rigid registration method, called warping, shifts pixels of the beam-steered images to best match the reference image. Linear prediction is used to find the warping vectors and decrease computational cost. An adaptive median-based combination technique for compounding is also investigated. The algorithms are tested on a spine phantom and human subjects. The results show a significant improvement in quality when using warping with adaptive median-based compounding.

Keywords: Warping, Registration, Spatial compounding, Adaptive, Epidural, Spine

a Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC, Canada

b Department of Ultrasound, British Columbia Women's Hospital and Health Centre, Vancouver, BC, Canada

c Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, Canada

d Department of Mechanical Engineering, University of British Columbia, Vancouver, BC, Canada

Corresponding author at: Dept. of Electrical and Computer Engineering, 2356 Main Mall, UBC, Vancouver, BC V6T 1Z4, Canada. Tel.: +1 604 822 2045; fax: +1 604 822 5949.

PII: S0895-6111(09)00079-2

doi:10.1016/j.compmedimag.2009.06.001

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