Slow motion cardiac imaging
First Claim
Patent Images
1. A method for representing slow motions of an oscillating heart, the method comprising the steps of:
- providing an oscillatory electrical signal of frequency fh representing an estimate of the oscillation cycle of the heart; and
using the signal of frequency fh, providing a sequence of electrical image signals of the heart at a frequency f=(1+m/N)fh, where N is a predetermined positive integer and m is an integer satisfying -(N-1)≦
m<
N, so that each of this sequence of electrical signals occurs in a different oscillation cycle of the heart.
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Abstract
Apparatus and method for representing slow motion of an oscillating heart by forming strobed images of the heart at a sequence of uniformly spaced times with controllable time interval lengths that are related to, but not identical to, the primary oscillation period T of the heart. The heart images may be formed at a sequence of times t=t0 +kMTh /N where t0 is an initial time, N is a positive integer, k=1,2, . . . , N-1 and M is a positive integer. Alternatively, the heart images may be formed at a sequence of times determined in part by the current oscillation cycle of the heart.
53 Citations
14 Claims
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1. A method for representing slow motions of an oscillating heart, the method comprising the steps of:
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providing an oscillatory electrical signal of frequency fh representing an estimate of the oscillation cycle of the heart; and using the signal of frequency fh, providing a sequence of electrical image signals of the heart at a frequency f=(1+m/N)fh, where N is a predetermined positive integer and m is an integer satisfying -(N-1)≦
m<
N, so that each of this sequence of electrical signals occurs in a different oscillation cycle of the heart. - View Dependent Claims (2, 3, 4)
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5. A method for forming slow motion images of an oscillating heart that produces a heart image synchronization signal representing completion of a heart oscillation cycle at a sequence of consecutive times th.sbsb.0 <
- th.sbsb.1 <
th.sbsb.2 <
. . . , the method comprising the steps of;determining a positive time increment Δ
t that is much less than an average heart cycle length;monitoring the actual heart oscillation cycle and determining the end, at times t=thk (k=0, 1, 2, . . . ), of each of a sequence of consecutive heart oscillation cycles; using the times Δ
t and thk to form and display a sequence of heart images at a sequence of image formation times given by
space="preserve" listing-type="equation">t=t.sub.k =t.sub.h.sbsb.k +k(Δ
t) (k=0, 1, 2, . . . , K)where the time interval defined by tK >
t<
tK+1 is the first such time interval for which two or more heart oscillation cycles end within that time interval.
- th.sbsb.1 <
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6. Apparatus for representing slow motions of an oscillating heart, the apparatus comprising:
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a source of an oscillatory digital signal of frequency fin approximately equal to the fundamental oscillation frequency of the heart; a digital processor having an input terminal to receive the oscillatory digital signal of frequency fin and to produce and issue an oscillatory output signal of frequency fout =fin /(1+m/N), where N is a positive integer and m is an integer satisfying -(N-1)≦
m;image formation means for receiving the digital processor output signal as an input signal thereto and, at the completion of each oscillation cycle of the image formation means input signal, for forming and issuing an image of the heart as an output signal after completion of an oscillation cycle, whereby each image formation means output signal is formed during a different oscillation cycle of the heart.
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7. Apparatus for representing slow motions of an oscillating heart, the apparatus comprising:
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a phase comparator having first and second input terminals to receive first and second signals and to form a difference signal proportional to a difference of these two signals, and having a comparator output terminal to issue the difference signal as an output signal; a source for providing an oscillatory signal of frequency fh approximately equal to the fundamental oscillation frequency of the heart, with this oscillatory signal being received at the first input terminal of the phase comparator; a voltage controlled oscillator having an input terminal to receive the output signal from the phase comparator and having an oscillator output terminal to issue as an output oscillatory signal whose oscillation frequency f varies monotonically with the voltage amplitude of the output signal from the phase comparator; a first frequency divider circuit, having an input terminal to receive the oscillatory signal of frequency f from the voltage controlled oscillator and having a first divider circuit terminal, to form and issue an oscillatory output signal at the first divider circuit output terminal with a frequency equal to f/N, where N is a predetermined positive integer, with this output signal being received by the second input terminal of the phase comparator; a second frequency divider circuit, having an input terminal to receive the oscillatory signal of frequency f from the voltage controlled oscillatory and having a second divider circuit terminal, to form and issue an oscillatory output signal at the second divider circuit terminal with a frequency equal to f/(N+m), where m is an integer satisfying -(N-1)≦
m; andimage formation means for receiving the oscillatory output signal from the second frequency divider circuit as an input signal at an image formation means input terminal and, after completion of each oscillation cycle of the input signal, for forming and issuing a sequence of images of the heart as an output signal, with each heart image being formed in a different oscillation cycle of the heart. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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Specification