US4204226A
Expired / Lapsed
US
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Real-time digital X-ray time interval difference imaging
Assignee: Wisconsin Alumni Research Foundation
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Filing: 1978-05-16
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Granted: 1980-05-20
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Expires: 1998-05-16
Abstract
Abstract Difference images, derived from an X-ray image of an anatomical subject, are produced in real time by directing X-rays through an anatomical subject to produce an X-ray image, converting the X-ray image into a series of television fields comprising trains of analog video signals, converting the analog video signals into corresponding digital video signals, integrating the digital video signals over a series of successive time intervals corresponding with a plurality of television fields and thereby producing a series of sets of integrated digital video signals, performing a series of subtractions between each set of integrated video signals and the preceding set of integrated video signals and thereby producing a series of successive digital difference video signals, converting the digital difference video signals into analog difference video signals, and converting the analog difference video signals into a series of visible television difference images representing changes in the X-ray image between the successive time intervals. Apparatus for carrying out this method is also disclosed.
Inventors
- 👤 Charles A. Mistretta
- 👤 Robert A. Kruger
- 👤 Theodore L. Houk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:42
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/48; A61B6/481; A61B6/50; A61B6/504; H; H04; H04N; H04N5/00; H04N5/30; H04N5/32; H04N5/3205; H05; H05G; H05G1/00; H05G1/08; H05G1/64
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
167 words
A method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through an anatomical subject to produce an X-ray image, converting said X-ray image into series of television fields comprising trains of analog video signals, converting said analog video signals into corresponding digital video signals, integrating said digital video signals over a series of successive time intervals each corresponding with a plurality of successive television fields and thereby producing a series of successive separate sets of integrated digital video signals, performing a series of successive subtractions between each successive separate set of integrated video signals and the immediately preceding set of integrated video signals and thereby producing a series of successive separate sets of digital difference video signals, converting said digital difference video signals into analog difference video signals, and converting said analog difference video signals into a series of successive visible television difference images representing changes in the X-ray image between the successive time intervals.
Claim 2
Independent Claim
167 words
A method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through an anatomical subject to produce an X-ray image, converting said X-ray image into series of television fields comprising trains of analog video signals, converting said analog video signals into corresponding digital video signals, integrating said digital video signals over a series of successive time intervals each corresponding with a plurality of successive television fields and thereby producing a series of successive separate sets of integrated digital video signals, performing a series of successive subtractions between each successive separate set of integrated video signals and the immediately preceding set of integrated video signals and thereby producing a series of successive separate sets of digital difference video signals, converting said digital difference video signals into analog difference video signals, and converting said analog difference video signals into a series of successive visible television difference images representing changes in the X-ray image between the successive time intervals.
Claim 3
Dependent Claim
22 words
A method according to claim 1, in which each of said time intervals is on the order of four consecutive television fields.
Claim 4
Dependent Claim
24 words
A method according to claim 1, including the step of providing filtration of the X-rays to enhance the visibility of an X-ray contrast medium.
Claim 5
Dependent Claim
32 words
A method according to claim 1, including the step of producing filtration of the X-rays with a filter medium containing cerium to enhance the visibility of an X-ray contrast medium containing iodine.
Claim 6
Dependent Claim
40 words
A method according to claim 1, including the step of introducing an X-ray contrast medium into the anatomical subject with a timing such that movement of the contrast medium in the subject will occur during the series of television fields.
Claim 7
Dependent Claim
24 words
A method according to claim 5, including the step of producing filtration of the X-rays to enhance the visibility of the X-ray contrast medium.
Claim 8
Dependent Claim
42 words
A method according to claim 1, including the step of introducing an X-ray contrast medium containing iodine into the anatomical subject with a timing such that movement of the contrast medium in the subject will occur during the series of television fields.
Claim 9
Dependent Claim
28 words
A method according to claim 7, including the step of producing filtration of the X-rays with a filter medium containing cerium to enhance the visibility of the iodine.
Claim 10
Dependent Claim
23 words
A method according to claim 1, including the step of logarithmically amplifying the analog video signals prior to the conversion to digital signals.
Claim 11
Dependent Claim
223 words
Diagnostic anatomical X-ray apparatus, comprising means including an X-ray source for producing an anatomical X-ray image, television means for converting said X-ray image into a series of television fields comprising trains of analog video signals, an analog-to-digital converter for converting said analog video signals into corresponding digital video signals, three memory systems for successively storing said digital video signals, cyclical means for successively supplying said digital video signals to said three memory systems in rotation for successive first, second and third time intervals, each of said memory systems comprising a digital memory having a capacity corresponding to at least one television field and integrating means for causing said digital memory to integrate said digital video signals over a predetermined number of successive television fields for the corresponding time interval, subtracting means for producing digital difference video signals by performing a subtraction between the two sets of integrated digital video signals stored in the most recently filled memory system and the previously filled memory system during the time interval when the other memory system is being filled, a digital-to-analog converter for converting said digital difference video signals into analog difference video signals, and means including a television display device for producing visible difference images corresponding to said analog difference video signals and representing changes in the anatomical X-ray image between the successive time intervals.
Claim 12
Dependent Claim
223 words
Diagnostic anatomical X-ray apparatus, comprising means including an X-ray source for producing an anatomical X-ray image, television means for converting said X-ray image into a series of television fields comprising trains of analog video signals, an analog-to-digital converter for converting said analog video signals into corresponding digital video signals, three memory systems for successively storing said digital video signals, cyclical means for successively supplying said digital video signals to said three memory systems in rotation for successive first, second and third time intervals, each of said memory systems comprising a digital memory having a capacity corresponding to at least one television field and integrating means for causing said digital memory to integrate said digital video signals over a predetermined number of successive television fields for the corresponding time interval, subtracting means for producing digital difference video signals by performing a subtraction between the two sets of integrated digital video signals stored in the most recently filled memory system and the previously filled memory system during the time interval when the other memory system is being filled, a digital-to-analog converter for converting said digital difference video signals into analog difference video signals, and means including a television display device for producing visible difference images corresponding to said analog difference video signals and representing changes in the anatomical X-ray image between the successive time intervals.
Claim 13
Dependent Claim
29 words
Diagnostic anatomical X-ray apparatus according to claim 10, including means for establishing each of said time intervals so as to be on the order of four successive television fields.
Claim 14
Dependent Claim
27 words
Diagnostic anatomical X-ray apparatus according to claim 10, comprising means for establishing each of said time intervals to correspond with a plurality of complete successive television fields.
Claim 15
Dependent Claim
30 words
Diagnostic anatomical X-ray apparatus according to claim 10, comprising X-ray filtration means between said X-ray source and said television means for enhancing the visibility of a predetermined X-ray contrast medium.
Claim 16
Dependent Claim
37 words
Diagnostic anatomical X-ray apparatus according to claim 10, comprising X-ray filtration means between said X-ray source and said television means, said X-ray filtration means containing cerium for enhancing the visibility of an X-ray contrast medium containing iodine.
Claim 17
Dependent Claim
25 words
Diagnostic anatomical X-ray apparatus according to claim 10, including a logarithmic amplifier for logarithmically amplifying said analog video signals for presentation to said analog-to-digital converter.
Claim 18
Dependent Claim
50 words
Diagnostic anatomical X-ray apparatus according to claim 10, in which said television means includes an image intensifier device for producing a visible anatomical image corresponding with said X-ray image, and a television camera for converting said visible image into a series of television fields comprising trains of analog video signals.
Claim 19
Dependent Claim
43 words
A method according to claim 1, including the step of producing filtration of the X-rays with a filter medium containing an element having a k-shell absorption edge between 40 and 60 k.e.v. to enhance the visibility of an X-ray contrast medium containing iodine.
Claim 20
Dependent Claim
39 words
A method according to claim 7, including the step of producing filtration of the X-rays with a filter medium containing an element having a K-shall absorption edge between 40 and 60 k.e.v. to enhance the visibility of the iodine.
Claim 21
Dependent Claim
48 words
Diagnostic anatomical X-ray apparatus according to claim 10, comprising X-ray filtration means between said X-ray source and said television means, said X-ray filtration means containing an element having a k-shell absorption edge between 40 and 60 k.e.v. for enhancing the visibility of an X-ray contrast medium containing iodine.
Claim 22
Independent Claim
188 words
A method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through an anatomical subject to produce an X-ray image, converting said X-ray image into a series of television fields comprising trains of analog video signals, converting said analog video signals directly into corresponding digital video signals in real time without any intervening analog storage, integrating said digital video signals in real time over a series of successive time intervals each corresponding with a plurality of successive television fields and thereby producing a series of successive separate sets of integrated digital video signals, performing a series of successive subtractions in real time between each successive set of integrated video signals and the immediately preceding set of integrated video signals and thereby producing a series of successive separate sets of digital difference video signals, converting said digital difference video signals in real time into analog difference video signals, and converting said analog difference video signals in real time into a series of successive visible television difference images representing changes in the X-ray image between the successive time intervals.
Claim 23
Independent Claim
188 words
A method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through an anatomical subject to produce an X-ray image, converting said X-ray image into a series of television fields comprising trains of analog video signals, converting said analog video signals directly into corresponding digital video signals in real time without any intervening analog storage, integrating said digital video signals in real time over a series of successive time intervals each corresponding with a plurality of successive television fields and thereby producing a series of successive separate sets of integrated digital video signals, performing a series of successive subtractions in real time between each successive set of integrated video signals and the immediately preceding set of integrated video signals and thereby producing a series of successive separate sets of digital difference video signals, converting said digital difference video signals in real time into analog difference video signals, and converting said analog difference video signals in real time into a series of successive visible television difference images representing changes in the X-ray image between the successive time intervals.
Claim 24
Dependent Claim
253 words
Diagnostic anatomical X-ray apparatus, comprising means including an X-ray source for producing an anatomical X-ray image, television means for converting said X-ray image into a series of television fields comprising trains of analog video signals, an analog-to-digital converter connected directly to said television means for converting said analog video signals into corresponding digital video signals in real time, three memory systems for successively storing said digital video signals in real time, cyclical means for successively supplying said digital video signals from said converter to said three memory systems in rotation in real time for successive first, second and third time intervals, each of said memory systems comprising a digital memory having a capacity corresponding to at least one television field and integrating means for causing said digital memory to integrate said digital video signals in real time over a predetermined number of successive television fields for the corresponding time interval, subtracting means for producing digital difference video signals by performing a subtraction in real time between the two sets of integrated digital video signals stored in the most recently filled memory system and the previously filled memory system during the time interval when the other memory system is being filled, a digital-to-analog converter for converting said digital difference video signals in real time into analog difference video signals, and means including a television display device for producing visible difference images in real time corresponding to said analog difference video signals and representing changes in the anatomical X-ray image between the successive time intervals.
Claim 25
Dependent Claim
253 words
Diagnostic anatomical X-ray apparatus, comprising means including an X-ray source for producing an anatomical X-ray image, television means for converting said X-ray image into a series of television fields comprising trains of analog video signals, an analog-to-digital converter connected directly to said television means for converting said analog video signals into corresponding digital video signals in real time, three memory systems for successively storing said digital video signals in real time, cyclical means for successively supplying said digital video signals from said converter to said three memory systems in rotation in real time for successive first, second and third time intervals, each of said memory systems comprising a digital memory having a capacity corresponding to at least one television field and integrating means for causing said digital memory to integrate said digital video signals in real time over a predetermined number of successive television fields for the corresponding time interval, subtracting means for producing digital difference video signals by performing a subtraction in real time between the two sets of integrated digital video signals stored in the most recently filled memory system and the previously filled memory system during the time interval when the other memory system is being filled, a digital-to-analog converter for converting said digital difference video signals in real time into analog difference video signals, and means including a television display device for producing visible difference images in real time corresponding to said analog difference video signals and representing changes in the anatomical X-ray image between the successive time intervals.
Claim 26
Dependent Claim
224 words
Diagnostic anatomical X-ray apparatus, comprising means including an X-ray source for producing an anatomical X-ray image, television means for converting said X-ray image into a series of television fields comprising trains of analog video signals, an analog-to-digital converter for converting said analog video signals in real time into corresponding digital video signals, three memory systems for successively storing said digital video signals in real time, cyclical means for successively supplying said digital video signals in real time to said three memory systems in rotation for successive first, second and third time intervals, each of said intervals corresponding with at least one television field. each of said memory systems comprising a digital memory having a capacity corresponding to at least one television field, subtracting means for producing digital difference video signals by performing a subtraction in real time between the two sets of digital video signals stored in the most recently filled memory system and the previously filled memory system during the time interval when the other memory system is being filled, a digital-to-analog converter for converting said digital difference video signals in real time into analog difference video signals, and means including a television display device for producing visible difference images in real time corresponding to said analog difference video signals and representing changes in the anatomical X-ray image between the successive time intervals.
Claim 27
Dependent Claim
224 words
Diagnostic anatomical X-ray apparatus, comprising means including an X-ray source for producing an anatomical X-ray image, television means for converting said X-ray image into a series of television fields comprising trains of analog video signals, an analog-to-digital converter for converting said analog video signals in real time into corresponding digital video signals, three memory systems for successively storing said digital video signals in real time, cyclical means for successively supplying said digital video signals in real time to said three memory systems in rotation for successive first, second and third time intervals, each of said intervals corresponding with at least one television field. each of said memory systems comprising a digital memory having a capacity corresponding to at least one television field, subtracting means for producing digital difference video signals by performing a subtraction in real time between the two sets of digital video signals stored in the most recently filled memory system and the previously filled memory system during the time interval when the other memory system is being filled, a digital-to-analog converter for converting said digital difference video signals in real time into analog difference video signals, and means including a television display device for producing visible difference images in real time corresponding to said analog difference video signals and representing changes in the anatomical X-ray image between the successive time intervals.
Claim 28
Independent Claim
237 words
A method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through an anatomical subject to produce an X-ray image, converting said X-ray image into a series of television fields comprising trains of analog video signals, converting said analog video signals into corresponding digital video signals, performing a first integrating cycle by integrating said digital video signals over first, second and third successive time intervals each corresponding with a plurality of successive television fields and thereby producing first, second and third successive separate sets of integrated digital video signals, performing a series of successive integrating cycles which are substantially the same as said first integrating cycle, repetitively performing a series of successive subtractions between (a) the second and first sets of integrated digital video signals of each cycle, (b) the third and second sets of integrated digital video signals of each cycle, and (c) the first set of integrated digital video signals of the second and subsequent cycles and the third set of integrated digital video signals of the immediately preceding cycle and thereby producing a repetitive series of successive separate sets of digital difference video signals, converting said digital difference video signals into corresponding analog difference video signals, and converting said analog difference video signals into a series of successive visible television difference images representing changes in the X-ray image between the successive time intervals.
Claim 29
Independent Claim
237 words
A method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through an anatomical subject to produce an X-ray image, converting said X-ray image into a series of television fields comprising trains of analog video signals, converting said analog video signals into corresponding digital video signals, performing a first integrating cycle by integrating said digital video signals over first, second and third successive time intervals each corresponding with a plurality of successive television fields and thereby producing first, second and third successive separate sets of integrated digital video signals, performing a series of successive integrating cycles which are substantially the same as said first integrating cycle, repetitively performing a series of successive subtractions between (a) the second and first sets of integrated digital video signals of each cycle, (b) the third and second sets of integrated digital video signals of each cycle, and (c) the first set of integrated digital video signals of the second and subsequent cycles and the third set of integrated digital video signals of the immediately preceding cycle and thereby producing a repetitive series of successive separate sets of digital difference video signals, converting said digital difference video signals into corresponding analog difference video signals, and converting said analog difference video signals into a series of successive visible television difference images representing changes in the X-ray image between the successive time intervals.
Claim 30
Dependent Claim
22 words
A method according to claim 23, in which each of said time intervals is on the order of four successive television fields.
Claim 31
Dependent Claim
24 words
A method according to claim 23, including the step of providing filtration of the X-rays to enhance the visibility of an X-ray contrast medium.
Claim 32
Dependent Claim
32 words
A method according to claim 23, including the step of producing filtration of the X-rays with a filter medium containing cerium to enhance the visibility of an X-ray contrast medium containing iodine.
Claim 33
Dependent Claim
40 words
A method according to claim 23, including the step of introducing an X-ray contrast medium into the anatomical subject with a timing such that movement of the contrast medium in the subject will occur during the series of television fields.
Claim 34
Dependent Claim
24 words
A method according to claim 27, including the step of producing filtration of the X-rays to enhance the visibility of the X-ray contrast medium.
Claim 35
Dependent Claim
42 words
A method according to claim 23, including the step of introducing an X-ray contrast medium containing iodine into the anatomical subject with a timing such that movement of the contrast medium in the subject will occur during the series of television fields.
Claim 36
Dependent Claim
28 words
A method according to claim 29, including the step of producing filtration of the X-rays with a filter medium containing cerium to enhance the visibility of the iodine.
Claim 37
Dependent Claim
23 words
A method according to claim 23, including the step of logarithmically amplifying the analog video signals prior to the conversion to digital signals.
Claim 38
Dependent Claim
43 words
A method according to claim 23, including the step of producing filtration of the X-rays with a filter medium containing an element having a k-shell absorption edge between 40 and 60 k.e.v. to enhance the visibility of an X-ray contrast medium containing iodine.
Claim 39
Dependent Claim
39 words
A method according to claim 29, including the step of producing filtration of the X-rays with a filter medium containing an element having a k-shell absorption edge between 40 and 60 k.e.v. to enhance the visibility of the iodine.
Claim 40
Independent Claim
258 words
A method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through an anatomical subject to produce an X-ray image, converting said X-ray image into a series of television fields comprising trains of analog video signals, converting said analog video signals directly into corresponding digital video signals in real time without any intervening analog storage, performing a first integrating cycle by integrating said digital video signals in real time over first, second and third successive time intervals each corresponding with a plurality of successive television fields and thereby producing first, second and third successive separate sets of integrated digital video signals, performing a series of successive integrating cycles which are substantially the same as said first integrating cycle, repetitively performing a series of successive subtractions in real time between (a) the second and first sets of integrated digital video signals of each cycle, (b) the third and second sets of integrated digital video signals of each cycle, and (c) the first set of integrated digital video signals of the second and subsequent cycles and the third set of integrated digital video signals of the immediately preceding cycle and thereby producing a repetitive series of successive separate sets of digital difference video signals, converting said digital difference video signals in real time into corresponding analog difference video signals, and converting said analog difference video signals in real time into a series of successive visible television difference images representing changes in the X-ray image between the successive time intervals.
Claim 41
Independent Claim
258 words
A method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through an anatomical subject to produce an X-ray image, converting said X-ray image into a series of television fields comprising trains of analog video signals, converting said analog video signals directly into corresponding digital video signals in real time without any intervening analog storage, performing a first integrating cycle by integrating said digital video signals in real time over first, second and third successive time intervals each corresponding with a plurality of successive television fields and thereby producing first, second and third successive separate sets of integrated digital video signals, performing a series of successive integrating cycles which are substantially the same as said first integrating cycle, repetitively performing a series of successive subtractions in real time between (a) the second and first sets of integrated digital video signals of each cycle, (b) the third and second sets of integrated digital video signals of each cycle, and (c) the first set of integrated digital video signals of the second and subsequent cycles and the third set of integrated digital video signals of the immediately preceding cycle and thereby producing a repetitive series of successive separate sets of digital difference video signals, converting said digital difference video signals in real time into corresponding analog difference video signals, and converting said analog difference video signals in real time into a series of successive visible television difference images representing changes in the X-ray image between the successive time intervals.
Claim 42
Independent Claim
256 words
A method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through an anatomical subject to produce an X-ray image, converting said X-ray image into a series of television fields comprising trains of analog video signals, converting said analog video signals directly into corresponding digital video signals in real time without any intervening analog storage, performing a first storage cycle by storing said digital video signals in real time over first, second and third successive time intervals each corresponding with at least one television field and thereby producing first, second and third successive separate sets of stored digital video signals, performing a series of successive storage cycles which are substantially the same as said first storage cycle, repetitively performing a series of successive subtractions in real time between (a) the second and first sets of stored digital video signals of each cycle, (b) the third and second sets of stored digital video signals of each cycle, and (c) the first set of stored digital video signals of the second and subsequent cycles and the third set of stored digital video signals of the immediately preceding cycle and thereby producing a repetitive series of successive separate sets of digital difference video signals, converting said digital difference video signals in real time into analog difference video signals, and converting said analog difference video signals in real time into a series of successive visible television difference images representing changes in the X-ray image between the successive time intervals.
Claim 43
Independent Claim
256 words
A method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through an anatomical subject to produce an X-ray image, converting said X-ray image into a series of television fields comprising trains of analog video signals, converting said analog video signals directly into corresponding digital video signals in real time without any intervening analog storage, performing a first storage cycle by storing said digital video signals in real time over first, second and third successive time intervals each corresponding with at least one television field and thereby producing first, second and third successive separate sets of stored digital video signals, performing a series of successive storage cycles which are substantially the same as said first storage cycle, repetitively performing a series of successive subtractions in real time between (a) the second and first sets of stored digital video signals of each cycle, (b) the third and second sets of stored digital video signals of each cycle, and (c) the first set of stored digital video signals of the second and subsequent cycles and the third set of stored digital video signals of the immediately preceding cycle and thereby producing a repetitive series of successive separate sets of digital difference video signals, converting said digital difference video signals in real time into analog difference video signals, and converting said analog difference video signals in real time into a series of successive visible television difference images representing changes in the X-ray image between the successive time intervals.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-05-20 | 1983-11-19 | 1984-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-05-20 | 1987-11-19 | 1988-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-05-20 | 1991-11-19 | 1992-05-20 | $7700.00 | Window Closed / Lapsed |