An eye-adapted beamforming for axial B-scans free from crystalline lens aberration : In vitro and ex vivo results with a 20 MHz linear array - Inserm - Institut national de la santé et de la recherche médicale Accéder directement au contenu
Communication Dans Un Congrès Année : 2015

An eye-adapted beamforming for axial B-scans free from crystalline lens aberration : In vitro and ex vivo results with a 20 MHz linear array

Résumé

In ophtalmic ultrasonography, axial B-scans are seriously deteriorated owing to the presence of the crystalline lens. This strongly aberrating medium affects both spatial and contrast resolution and causes important distortions. To deal with this issue, an adapted beamform-ing (BF) has been developed and experimented with a 20 MHz linear array working with a custom US research scanner. The adapted BF computes focusing delays that compensate for crystalline phase aberration, including refraction effects. This BF was tested in vitro by imaging a wire phantom through an eye phantom consisting of a synthetic gelatin lens, shaped according to the un-accommodated state of an adult human crystalline lens, anatomically set up in an appropriate liquid (turpentine) to approach the in vivo velocity ratio. The synthetic lens shape corresponded to that of an adult human crystalline lens in unaccommodated state. Both image quality and fidelity from the adapted BF were assessed and compared with conventional delay-and-sum BF over the aberrating medium. Results showed 2-fold improvement of the lateral resolution, greater sensitivity and 90% reduction of the spatial error (from 758 µm to 76 µm) with adapted BF compared to conventional BF. Finally, promising first ex vivo axial B-scans of a human eye are presented.
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inserm-01145624 , version 1 (24-04-2015)

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  • HAL Id : inserm-01145624 , version 1

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Tony Matéo, Yassine Mofid, Frédéric Ossant. An eye-adapted beamforming for axial B-scans free from crystalline lens aberration : In vitro and ex vivo results with a 20 MHz linear array. Journées RITS 2015, Mar 2015, Dourdan, France. p68-69 Section imagerie et thérapie par ultrasons. ⟨inserm-01145624⟩
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