title: Spectral image reconstruction for transcranial ultrasound measurement.
abstract: An approach aimed at improved ultrasound resolution and signal strength through highly attenuating media is presented. The method delivers a series of multiple-cycle bursts in order to construct a discrete spectral (frequency domain) response in one dimension. Cross-correlation of this ultrasound A-mode response with its transmitted signal results in time-localized peaks that correspond to scattering locations. The approach is particularly relevant to the problem of transcranial ultrasound imaging, as it combines numerous smaller signals into a single signal whose net power may exceed that which could be achieved using a single burst. Tests are performed with human skull fragments and nylon-wire targets embedded in a tissue phantom. Skulls are oriented to produce both lateral and shear modes of transcranial propagation. A total of nine locations distributed over three ex vivo human skull samples are studied. Compared with pulsed and chirped signals, results indicate more localized peaks when using the multi-cycle approach, with more accurate positioning when combined with the transcranial shear mode.
authors.affiliation: Department of Radiology, Harvard Medical School, Brigham and Women's Hospital, Boston, MA 02115, USA.
authors.forename: Greg T
authors.initials: GT
authors.lastname: Clement
mesh_terms: D000465:Algorithms; D001921:Brain / Q000473:pathology*; D003198:Computer Simulation; D003952:Diagnostic Imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D015233:Models, Statistical; D019047:Phantoms, Imaging; D012542:Scattering, Radiation; D012886:Skull / Q000000981:diagnostic imaging* / Q000473:pathology; D013997:Time Factors; D014465:Ultrasonics; D014463:Ultrasonography