Method and apparatus for adaptive focusing in a medical ultrasound imaging apparatus
First Claim
1. A method for generating an ultrasound B-image of an examination subject having acoustic inhomogeneities using an ultrasound array having a plurality of transducer elements, each transducer element having a variable delay associated therewith, including a delay used for a standard focusing of said ultrasound array, said method comprising the steps of:
- scanning a sectional plane of said examination subject with focused ultrasound beams from said ultrasound array in an adaptation phase;
measuring, in said adaptation phase, echo signals reflected by said examination subject using a selected active aperture, said echo signals being disturbed by the acoustic inhomogeneities in said examination subject;
calculating correction values for the delay of each of said element in said ultrasound array from the delays used for said standard focusing based on the measured values obtained in said adaptation phase; and
scanning said examination subject with said ultrasound array using the delays calculated based on said correction values and the delays used for said standard focusing to compensate for said disturbances caused by said acoustic inhomogeneities to obtain further echo signals; and
generating a standard B-image from said further echo signals.
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Abstract
A sectional plane of the examination subject is first scanned by focused ultrasound transmission beams in an adaptation phase. Disturbing effects from the reflected echo signals which are caused by the inhomogenities in the tissue are thereby measured. In this adaptation phase, correction values for the delay time of the signals of the elemental transducers of the ultrasound array in comparison to the standard focusing are also derived from the measured values. In a following B-image imaging phase, the delay times of the active aperture are then varied dependent on the correction values during the emission and/or during reception. The disturbing effects are thereby compensated. A method and apparatus are disclosed which are especially well-suited for linear array systems and for patients having inhomogeneous tissues.
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Citations
20 Claims
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1. A method for generating an ultrasound B-image of an examination subject having acoustic inhomogeneities using an ultrasound array having a plurality of transducer elements, each transducer element having a variable delay associated therewith, including a delay used for a standard focusing of said ultrasound array, said method comprising the steps of:
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scanning a sectional plane of said examination subject with focused ultrasound beams from said ultrasound array in an adaptation phase; measuring, in said adaptation phase, echo signals reflected by said examination subject using a selected active aperture, said echo signals being disturbed by the acoustic inhomogeneities in said examination subject; calculating correction values for the delay of each of said element in said ultrasound array from the delays used for said standard focusing based on the measured values obtained in said adaptation phase; and scanning said examination subject with said ultrasound array using the delays calculated based on said correction values and the delays used for said standard focusing to compensate for said disturbances caused by said acoustic inhomogeneities to obtain further echo signals; and generating a standard B-image from said further echo signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for generating an ultrasound B-image of an examination subject having acoustic inhomogeneities comprising:
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an ultrasound array having a plurality of transducer elements, each transducer element having means connected thereto for variably setting a delay for that transducer, including a delay for standard focusing of said ultrasound array; means for scanning said examination subject with ultrasound beams generated by said ultrasound array with said delays for standard focusing; means for processing ultrasound echo signals reflected by said examination subject using a selected active aperture and for generating a standard B-image therefrom; means for scanning a sectional plane of said examination subject with focused ultrasound beams from said array in an adaptation phase; means for measuring echo signals reflected by said examination subject in said adaptation phase disturbed by the acoustic inhomogeneities in said examination subject; means for calculating correction values for the delay of each element in said ultrasound array from the delays used for said standard focusing based on the measured values obtained in said adaptation phase; and means for scanning said examination subject with said ultrasound array based on said correction values and the delays used for said standard focusing for compensating for said disturbances caused by said acoustic inhomogeneities. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification