title: Aberration correction by time reversal of moving speckle noise.
abstract: Focusing a wave through heterogeneous media is an important problem in medical ultrasound imaging. In such aberrating media, in the presence of a small number of point reflectors, iterative time reversal is a well-known method able to focus on the strongest reflector. However, in presence of speckle noise generated by many non-resolved scatterers, iterative time reversal alone does not work. In this paper, we propose the use of the echoes coming from moving particles in a flow, such as red blood cells, to generate a virtual point reflector by iterative time reversal. The construction of the virtual point reflector is performed by a coherent addition of independent realizations of speckle coming from moving particles. After focusing on a virtual point reflector, ultrasound images can be locally corrected inside an isoplanatic patch. An application for the correction of power Doppler images is presented. A theoretical analysis shows that this iterative method allows focusing on the point of maximal insonification of the uncorrected beam.
authors: Institut Langevin, Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris-ESPCI, ParisTech, Inserm U979, CNRS UMR7587, Universite Denis Diderot, France. bruno-felix.osmanski@espci.fr
authors: Bruno-Felix
authors: BF
authors: Osmanski
authors: Gabriel
authors: G
authors: Montaldo
authors: Mickaël
authors: M
authors: Tanter
authors: Mathias
authors: M
authors: Fink
mesh_terms: D000465:Algorithms; D016477:Artifacts; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012212:Rheology / Q000379:methods*; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*