Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
2001-05-22
2004-02-03
Lateef, Marvin M. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C600S445000, C600S437000
Reexamination Certificate
active
06685643
ABSTRACT:
The present invention relates to a method and a device for recording ultrasonic images, specifically for real-time recording and displaying three-dimensional ultrasonic images, in accordance with the introductory clauses of claims
1
and
12
, as well as to the application of this method or this device in accordance with the claims
17
to
19
.
Such methods and devices for recording ultrasonic images of an object are known, wherein an ultrasonic emitter emits ultrasonic waves onto an object while an ultrasonic receiver receives the ultrasonic waves reflected by the object. For recording the object, the ultrasonic emitter or the ultrasonic receiver, respectively, is displaced along the object or rotated relative to the object while individual image sub-areas of the object are recorded. As a rule, these partial image areas correspond to a linewise scanning of the object, in which operation the object is recorded by lines along a recording direction in which the ultrasonic emitter or the ultrasonic receiver is displaced. In the known ultrasonic devices, the images generated in the ultrasonic device can be transferred in digital form or via a video output into a post-processing device or into a data processing system, respectively. There the images can be stored or directly post-processed.
With the scanning operation the object to be examined is recorded by lines, which means that individual “layers” of the object, which are parallel to each other, or “slices” of the object, which are in mutual rotational symmetry, are exposed to ultrasonic waves and that the corresponding reflected ultrasonic waves are received in the ultrasonic device. The received ultrasonic waves are processed in the data processing system such that a halftone image is produced on a display device, with the individual halftones corresponding each to ultrasonic waves reflected more strongly or weakly.
The individual layers or slices of the object, i.e. the individual lines recorded in the ultrasonic scanning operation are “superimposed” in the data processing system so as to obtain a three-dimensional representation of the object on the display device. The different spacings of various regions of a layer, i.e. the position of cavities or regions of more strongly compacted material of the object relative to the ultrasonic device, are obtained by evaluation of the halftone information of each layer.
A sound transmitting medium, which enhances the propagation of ultrasonic waves, is provided between the ultrasonic device and the object to be recorded. This sound transmitting medium is represented by a uniform halftone in the corresponding halftone image. In particular, the outside contours of an object can be determined by the provision that the first halftone variations on the boundary between the sound transmitting medium and the object to be examined are detected in the halftone image and that their respective relative spacing from the ultrasonic device is measured.
The ultrasonic methods make use of a pre-defined halftone grade (threshold) or a grade to be computed in order to find contours in the image. The contour information is then stored in an image and, after evaluation of the respective spacings between the ultrasonic device or the ultrasonic transmitter, respectively, and the outside contours of the object to be examined, furnish then a three-dimensional impression of the image.
These known ultrasonic methods are suitable, for instance, for examining a foetus inside the mother's abdominal cavity or for detection of renal calculi inside the human body. For recording the object to be examined, which is located, for instance, inside the human body, the ultrasonic device is connected to the skin surface on the human body by means of a sound transmitting medium such as a gel, oil or waters and is then moved or rotated along a desired recording direction whilst ultrasound images are recorded during uniform distances in time or space. The entire scanning operation extends over a defined area of the human body, with individual layers or slices of the object under examination inside the body being recorded during the scanning operation in succession. The individual ultrasonic images are then joined in a spatially correct succession in a subsequently employed data processing system so that a complete or three-dimensional image of the object is achieved by “superimposition” of the individual images. Then “artificial” two-dimensional images in this three-dimensional image can be calculated in the data processing system.
Ultrasonic techniques employed in practical clinical applications for the three-dimensional recording of human organs are presently operating on a tomography basis, which means that the volume is composed of the individual recorded layer planes or slices. In trans-oesophageal echo cardiography, for example, a pivotable endoscopic probe is introduced through the patient's oesophagus. The ultrasonic sensor is integrated as so-called “phased array” into the tip of the probe. In this technique the ultrasonic transducer on the tip of the probe is linearly shifted or rotated so that a layer of the organ is scanned from each angular position of the rotating ultrasonic transducer or from each shifted probe position. One image sequence, i.e. one or several cycles of movement of the organ, such as a cardiac cycle, is produced per layer.
When such a sequence has been recorded the rotation of the ultrasonic transducer is continued by a desired angular increment, using a motor such as a stepping or linear motor, or the transducer is shifted by hand or along a linear path in the case of linear shift. Then a data processing system triggers the next recording sequence, with this data processing system being capable of processing both the data of the electro cardiogram (ECG) and the respiratory or thorax movements (respiration scan).
With coupling the ECG to the recording times an attempt is made to record each image of a sequence always at a defined phase point during the cycle of the hear beat. As a result, it is possible to generate sequences of three-dimensional images of moved objects or organs inside organisms, which, when joined in succession, furnish a three-dimensional representation of the organ as a function of time. The organ movement can then be cyclically viewed as in a “film”.
It is particularly important in these methods that the distances between the individual “layers”, i.e. between the individual image sub-areas of the object under examination, are almost constant in order to avoid a longitudinal distortion of the overall image along the recording direction, i.e. along the scanning axis. In order to achieve a uniform recording rate, i.e. a uniform rate of the ultrasonic transducer along the recording direction during the scanning operation, the conventional techniques either operate on motor-controlled mechanical systems for moving the ultrasonic device or magnetic position detectors or optical systems for detecting the respective precise position of the ultrasonic device with respect to the corresponding record of the image sub-area, i.e. the corresponding “layer” of the object under examination. Due to the detection of the precise position of the ultrasonic device during the operation of recording such a “layer” it is possible later on to compose the individual image sub-areas, i.e. the individual “layers” of the object examined, in the data processing system in a form corresponding to reality. In the conventional systems image distortions along the recording direction can hence be avoided.
From the German Patent DE 38 29 603 A1, for example, an ultrasonic endoscopic device is known that is provided, over a distal terminal section, with a flexible hose accommodating a longitudinally displaceable ultrasonic transducer on a slide for the creation of multi-plane tomograms. In this case, too, a defined volume is to be scanned in multiple planes with high precision in order to be able to reconstruct a precise three-dimensional representation of the sectional images so obtained. There th
Kaiser Dietmar
Miyamoto Kiyoji
Mumm Bernhard
Waldinger Johannes
Jung William
Lateef Marvin M.
Sheridan & Ross P.C.
Tomtec Imaging Systems GmbH
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