Power spectral strain estimators in elastography

US6494834B2 · kind B2 · utility

Assignee

• The Board of Regents of the University of Texas System · US

Inventors

• Elisa E. Konofagou · New York, US
• Jonathan Ophir · Austin, US

Key dates

• Filing date: Mar 16, 2001
• Grant date: Dec 17, 2002
• Expiry date: May 29, 2021

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N2291/012
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Elastography can produce quality strain images in vitro and in vivo. Standard elastography uses a coherent cross-correlation technique to estimate tissue displacement and tissue strain using a subsequent gradient operator. While coherent estimation methods generally have the advantage of being highly accurate and precise, even relatively small undesired motions are likely to cause enough signal decorrelation to produce significant degradation of the elastogram. For elastography to become more universally practical in such applications as hand-held, intravascular and abdominal imaging, the limitations associated with coherent strain estimation methods that require tissue and system stability, must be overcome. In this paper, we propose the use of a spectral shift method that uses a centroid shift estimate to measure local strain directly. Furthermore, we also show theoretically that a spectral bandwidth method can also provide a direct strain estimation. We demonstrate that strain estimation using the spectral shift technique is moderately less precise but far more robust than the cross-correlation method. A theoretical analysis as well as simulations and experimental results are us…