Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
2001-02-06
2002-10-15
Jaworski, Francis J. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
Reexamination Certificate
active
06464644
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method of ultrasonic imaging and an ultrasonic diagnostic apparatus, and more particularly to a method of ultrasonic imaging and an ultrasonic diagnostic apparatus capable of producing ultrasonic images by which it is possible to visually recognize at a glance the time-wise change of a blood flow.
In obtaining an ultrasonic image of a blood flow, there has been a convention to use small bubbles in blood as the contrast agent. These small bubbles disperse by being hit by a strong ultrasonic wave.
On this account, after the imaging for a high-transmission frame (a frame taken by use of an ultrasonic wave which is strong enough to disperse the contrast agent), imaging for low-transmission frames (frames taken by use of an ultrasonic wave which is not so strong as to disperse the contrast agent) is carried out continuously, and imaging for another high-transmission frame is carried out on expiration of the time at which the view field is filled with a blood flow including the contrast agent, with these operations being implemented cyclically, as shown in FIG.
1
.
In
FIG. 1
, vertical line segments aligning along the time axis represent transmission time points and transmission strengths of sonic beams which form the frames.
FIG.
2
(
a
) shows sonic beams which form a high-transmission frame, and the bold lines signify an ultrasonic wave which is strong enough to disperse the contrast agent. Indicated by V is a blood vessel, and the arrow indicates the direction of blood flow.
In contrast, FIG.
2
(
b
) shows sonic beams which form a low-transmission frame, and the thin lines signify an ultrasonic wave which is not so strong as to disperse the contrast agent.
It has been possible to view the state of a blood flow at one moment in the image of a high-transmission frame which is taken based on the above-mentioned conventional scheme.
However, this scheme has been problematic in that it cannot provide a view of the time-wise change of a blood flow. Specifically, if it is intended to view the time-wise change of a blood flow, it is necessary to compare images of high-transmission frames taken at different time points, and it necessitates skill.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method of ultrasonic imaging and an ultrasonic diagnostic apparatus capable of producing ultrasonic images by which it is possible to visually recognize at a glance the time-wise change of a blood flow.
At a first viewpoint, the present invention provides a method of ultrasonic imaging which is characterized by transmitting an ultrasonic wave at such a strength as to disperse the contrast agent for part of a number of sonic beams which form one frame and transmitting an ultrasonic wave at such a strength as not to disperse the contrast agent for other sonic beams, and producing an image for one frame from received signals which correspond to the ultrasonic wave transmission.
In the ultrasonic imaging method of the first viewpoint, the contrast agent in one part of the image disperses, while the contrast agent in other part does not disperse. Therefore, when another imaging takes place after such a time length that the flow range is present within the view field, the portion with the contrast agent being dispersed moves slightly in its position on the image. When this operation is repeated for a flow which intersects the direction of sonic beam, an effect similar to the tagging in magnetic resonance imaging emerges, and the flow seems to have a stripe pattern indicative of the passing time. As a result, it becomes possible to visually recognize the time-wise change of a blood flow at a glance.
At a second viewpoint, the present invention provides a method of ultrasonic imaging which is characterized by transmitting an ultrasonic wave at such a strength as not to disperse the contrast agent for all of a number of sonic beams which form one frame, producing an image for one frame from received signals which correspond to the ultrasonic wave transmission, and interposing the formed frame between frames which are produced by the ultrasonic imaging method mentioned in the first viewpoint.
In the ultrasonic imaging method of the second viewpoint, a frame without the dispersion of contrast agent is interposed between frames with the dispersion of contrast agent in part of the image, whereby the real-time property of progressive imaging can be improved.
At a third viewpoint, the present invention provides a method of ultrasonic imaging which is derived from the method of the second viewpoint, and is characterized in that one timing of ultrasonic wave transmission for one frame at such a strength as to disperse the contrast agent and another timing of ultrasonic wave transmission for a later frame at such a strength as to disperse the contrast agent have a time difference which is based on the heart beat.
In the ultrasonic imaging method of the third viewpoint, there is provided a time difference between events of transmission by which the contrast agent is dispersed in part of the image, whereby a pulsing flow can be observed properly.
At a fourth viewpoint, the present invention provides a method of ultrasonic imaging which is derived from the method of the third viewpoint, and is characterized in that there are in one frame at least two spaced-out sonic beams for which an ultrasonic wave is transmitted at such a strength as to disperse the contrast agent.
In the ultrasonic imaging method of the fourth viewpoint, the contrast agent disperses at least two spaced-out positions, whereby a number of stripe patterns can be appended to a flow at the same time.
At a fifth viewpoint, the present invention provides a method of ultrasonic imaging which is characterized by transmitting an ultrasonic wave at such a strength as to disperse the contrast agent for a certain depth of a number of sonic beams which form one frame or a certain depth seen from the ultrasonic probe and transmitting an ultrasonic wave at such a strength as not to disperse the contrast agent for other depths, and producing an image for one frame from received signals which correspond to the ultrasonic wave transmission.
In the ultrasonic imaging method of the fifth viewpoint, the contrast agent in one part of the image disperses, whereas the contrast agent in other part does not disperse. Therefore, when another imaging takes place after such a time length that the flow range is present within the view field, the portion with the contrast agent being dispersed moves slightly in its position on the image. When this operation is repeated for a flow which intersects the direction of sonic beam, an effect similar to the tagging in magnetic resonance imaging emerges, and the flow seems to have a stripe pattern indicative of the passing time. Whereby, it becomes possible to visually recognize at a glance the time-wise change of a blood flow.
At a sixth viewpoint, the present invention provides a method of ultrasonic imaging which is characterized by transmitting an ultrasonic wave at such a strength as not to disperse the contrast agent for all of a number of sonic beams which form one frame, producing an image for one frame from received signals which correspond to the ultrasonic wave transmission, and interposing the formed frame between frames which are produced by the ultrasonic imaging method mentioned in the fifth viewpoint.
In the ultrasonic imaging method of the sixth viewpoint, a frame without the dispersion of contrast agent is interposed between frames with the dispersion of contrast agent in part of the image, whereby the real-time property of progressive imaging can be improved.
At a seventh viewpoint, the present invention provides a method of ultrasonic imaging which is derived from the method of the sixth viewpoint, and is characterized in that one timing of ultrasonic wave transmission for one frame at such a strength as to disperse the contrast agent and another timing of ultrasonic wave transmission for a later frame at such a strength
GE Medical Systems Global Technology Company LLC
Jaworski Francis J.
Kojima Moonray
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