title: A restoration framework for ultrasonic tissue characterization.
abstract: Ultrasonic tissue characterization has become an area of intensive research. This procedure generally relies on the analysis of the unprocessed echo signal. Because the ultrasound echo is degraded by the non-ideal system point spread function, a deconvolution step could be employed to provide an estimate of the tissue response that could then be exploited for a more accurate characterization. In medical ultrasound, deconvolution is commonly used to increase diagnostic reliability of ultrasound images by improving their contrast and resolution. Most successful algorithms address deconvolution in a maximum a posteriori estimation framework; this typically leads to the solution of l(2)-norm or (1)-norm constrained optimization problems, depending on the choice of the prior distribution. Although these techniques are sufficient to obtain relevant image visual quality improvements, the obtained reflectivity estimates are, however, not appropriate for classification purposes. In this context, we introduce in this paper a maximum a posteriori deconvolution framework expressly derived to improve tissue characterization. The algorithm overcomes limitations associated with standard techniques by using a nonstandard prior model for the tissue response. We present an evaluation of the algorithm performance using both computer simulations and tissue-mimicking phantoms. These studies reveal increased accuracy in the characterization of media with different properties. A comparison with state-of-the-art Wiener and l(1)-norm deconvolution techniques attests to the superiority of the proposed algorithm.
authors.affiliation: Advanced Research Center on Electronic Systems for Information and Communication Technologies E. De Castro (ARC ES), Università di Bologna, Bologna, Italy. martino.alessandrini@creatis.insa-lyon.fr
authors.forename: Martino
authors.initials: M
authors.lastname: Alessandrini
authors.forename: Simona
authors.initials: S
authors.lastname: Maggio
authors.forename: Jonathan
authors.initials: J
authors.lastname: Porée
authors.forename: Luca
authors.initials: L
authors.lastname: De Marchi
authors.forename: Nicolo
authors.initials: N
authors.lastname: Speciale
authors.forename: Emilie
authors.initials: E
authors.lastname: Franceschini
authors.forename: Olivier
authors.initials: O
authors.lastname: Bernard
authors.forename: Olivier
authors.initials: O
authors.lastname: Basset
mesh_terms: D000465:Algorithms; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*