US4817614A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for adaptive focusing in a medical ultrasound imaging apparatus
Assignee: Siemens AG
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Filing: 1987-08-19
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Granted: 1989-04-04
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Expires: 2007-08-19
Abstract
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.
Inventors
- 👤 Dietrich Hassler
- 👤 Heinz Eschenbacher
- 👤 Wolfgang Haerer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:28
CPC Classifications
G; G01; G01S; G01S15/00; G01S15/88; G01S15/89; G01S15/8906; G01S15/8977; G01H; G01H17/00; G01N; G01N29/00; G01N29/04; G01N29/06; G01N29/0609; G01N29/0645; G01S15/8909; G01S15/8915; G01S15/8927; G01S7/00; G01S7/52; G01S7/52017; G01S7/52046; G01S7/52049; G01S7/5205; G01S7/52053; G01S7/52057; G01S7/5206
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
185 words
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.
Claim 2
Independent Claim
185 words
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.
Claim 3
Dependent Claim
31 words
A method as claimed in claim 1, wherein the step of calculating said correction values is further defined by cross-correlation the echo signals from said transducer elements of said ultrasound array.
Claim 4
Dependent Claim
27 words
A method as claimed in claim 2, wherein the step of cross-correlating is further defined by cross-correlating echo signals of two neighboring transducer elements in said ultrasound
Claim 5
Dependent Claim
46 words
A method as claimed in claim 2, wherein the step of cross-correlating is further defined by the steps of: grouping said transducer elements of said ultrasound array into a plurality of groups; and cross-correlating the echo signals from neighboring groups of transducers in said ultrasound array.
Claim 6
Dependent Claim
76 words
A method a claimed in claim 2, wherein the step of calculating said correction values is further defined by the steps of: identifying the time shift value of the maximum of said cross-correlation; generating a distribution of transit-time differences by comparing said time shift value to an expected value for a homogeneous examination subject; and after scanning the entirety of said sectional plane, deriving said measuring values from said distribution and calculating said correction values therefrom.
Claim 7
Dependent Claim
24 words
A method as claimed in claim 1, wherein the step of calculating said correction values is further defined by calculating correction values by averaging.
Claim 8
Dependent Claim
26 words
A method as claimed in claim 6, comprising the additional step of tilting said ultrasound array with respect to said examination subject in said adaptation phase.
Claim 9
Dependent Claim
32 words
A method as claimed in claim 5, comprising the additional step of: aligning the time shift values from said transducer elements when calculating said correction values; and subsequently averaging said correction values.
Claim 10
Dependent Claim
39 words
A method as claimed in claim 1, wherein said adaptation phase is repeated through a selected number of iterations, with the correction values obtained from one iteration being used for transmitting said ultrasound beams in an immediately following iteration.
Claim 11
Independent Claim
203 words
An apparatus for generating an ultrasound B-image of an examination subject having acoustic inhomogeneities comprising: 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.
Claim 12
Independent Claim
203 words
An apparatus for generating an ultrasound B-image of an examination subject having acoustic inhomogeneities comprising: 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.
Claim 13
Dependent Claim
31 words
An apparatus as claimed in claim 10, wherein said means for calculating said correction values is a means for cross-correlating the echo signals from said transducer elements of said ultrasound array.
Claim 14
Dependent Claim
27 words
A apparatus as claimed in claim 11, wherein said means for cross-correlating is a means for cross-correlating echo signals of two neighboring transducer elements in said ultrasound
Claim 15
Dependent Claim
47 words
An apparatus as claimed in claim 11, further comprising means for grouping said transducer elements of said ultrasound array into a plurality of groups, and wherein said means for cross-correlating is a means for cross-correlating the echo signals from neighboring groups of transducers in said ultrasound array.
Claim 16
Dependent Claim
76 words
An apparatus as claimed in claim 11, wherein said means for calculating said correction values comprises: means for identifying a time shift value of the maximum of the output of said means for cross-correlating; means for generating a distribution of transit-time differences including means for comparing said time shift value to an expected value for an homogeneous examination subject; and means for deriving said measured values from said distribution and for calculating said correction values therefrom.
Claim 17
Dependent Claim
19 words
An apparatus as claimed in claim 10, wherein said means for calculating said correction values includes means for averaging.
Claim 18
Dependent Claim
42 words
An apparatus as claimed in claim 15, wherein said means for calculating said correction values includes means for aligning added time shift values from said transducer elements when calculating said correction values and means for subsequently averaging said correction values after aligning.
Claim 19
Dependent Claim
25 words
An apparatus as claimed in claim 10, further comprising means for tilting said ultrasound array with respect to said examination subject in said adaptation phase.
Claim 20
Dependent Claim
42 words
An apparatus as claimed in claim 10, further comprising control means for repeating said adaptation phase through a selected number of iterations, with the correction values obtained for one iteration being used for transmitting said ultrasound beams in an immediately following iternation.
Claim 21
Dependent Claim
43 words
An apparatus as claimed in claim 10, further comprising means for averaging a plurality of scans of said examination subject, and means for selectively varying the duration of said adaptation phase to control the number of scans used in said means for averaging.
Claim 22
Dependent Claim
26 words
An apparatus as claimed in claim 10, further comprising means for selecting the depth region in said examination subject from which said echo signals are reflected.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-04-03 | 1992-10-03 | 1993-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-03 | 1996-10-03 | 1997-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-03 | 2000-10-03 | 2001-04-04 | $7700.00 | Window Closed / Lapsed |