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This paper presents first results concerning the three-dimensional ultrasonic data acquisition, the textural analysis of different classes of tissues and the tissue-specific display of mastopathic regions within the female breast, revealing its benefit for diagnosis.

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This is the first report in literature on three-dimensional imaging of organs via sonography. The relevant experiments were performed in vitro. Whereas MRI and CT can produce three-dimensional images of bodies by means of appropriate computer programmes, we had to search for special techniques in sonography that would communicate to the computer the exact positioning and arrangement of the individual segments to be reconstructed to supply a three-dimensional image. In MRI and CT the individual segments are arranged parallel to one another; the distance between the individual segments is known; all the computer has to do is to add up these segments to produce a spatial image. In contrast to this, conventional sonography cannot supply parallel segments or sections due to the unevenness of the human skin. Hence, it was not possible to use the computer programmes compiled for the three-dimensional reconstruction of MRI and CT images, in sonography; special transducer guides had to be constructed before this could be realised. One of our special constructions enabled parallel shifting of the transducer to obtain parallel segments or sections, and another construction enabled rotation of the transducer to obtain segments or sections differing from one another by a known angle of displacement. In this manner the computer was able to reconstruct an organ to supply a three-dimensional image--a first-time achievement. Using these devices, we examined a kidney in a water-bath. By means of outlining of the individual sonographic segments, only their surfaces are depicted, and these are reconstructed to produce a three-dimensional body by means of newly developed computer programmes.(ABSTRACT TRUNCATED AT 250 WORDS)

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This is a report on the clinical use of sonographic imaging. Experimental studies have shown that parallel sonographic sections are available only in vitro, which means no in-vivo three-dimensional reconstruction is possible as it is with magnetic resonance and computed tomography. The idea that a coordinated sequence of sections can be obtained by spatial rotation of the plane of sound so that the individual sections differ from one another by defined angular distances, enables three-dimensional reconstruction of sonographic in-vivo sections. A transducer was constructed that enables the production of sonographic sections rotating around a fixed center of rotation. Its clinical usefulness was tried and confirmed in the imaging of early pregnancies, benign and malignant carcinomas of the breast, and in imaging a gallbladder with a solitary gallstone. Three-dimensional imaging can be achieved either as a ring-shaped structure or with a continuous surface. This points to the possibility of diagnosing malformations early in pregnancy if the number of sections is sufficiently high. In tumour imaging the malignant tumour seems to be clearly distinguishable from the benign one; three-dimensional diagnosis is likely to furnish important additional criteria in diagnosis. Further clinical studies will have to verify this.

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After satisfactory experimental results with three-dimensional data acquisition and presentation of the kidney in vitro, we wanted to show how our technique could be used for medical application in vivo, such as ultrasonic 3D reconstruction of organs. The sector scans were taken by rotating the scan head 10 degrees in any direction around the length of the axis. The organ was scanned with 18 images and reconstructed. The digital images, using the organ contours, allowed 3D reconstruction of the original organ, relying on the computer memory. The first results in reconstructing uteri show how this scan head can be used in combination with the computer programs for medical application. For the first time, it has become possible to present computer-generated views of an organ cross-section that has been impossible to obtain by means of traditional ultrasound techniques. Recent experiments using this method show new ways of diagnosing tumors.

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This is the first report on the 3-dimensional representation of organs with US. The prerequisite for this was a coordinated transducer movement, in such a manner that the organ under examination was represented by US sections differing in only one of the space coordinates. Such transducer movement was made possible by 2 devices. In the first instance, longitudinal movement of the transducer resulted in the production of parallel sections of the organ while, in the other instance, rotation of the transducer head permitted sections arranged around a fixed center-point. Using a special computer program, the sections were contoured in such a manner that only the surface of the organ was represented. These sections were then arranged in space. The 3-dimensional representation can be effected both by binary image representation and by representation with closed (intact) body surface. The advantage of the binary image representation is the fact that the organ surfaces "extracted" from the original US sections are directly incorporated within the 3-dimensional image build-up, with no further computer manipulations. It can be seen that the rotation of the transducer head represents the practicable possibility for the use in the clinical setting.

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Using a newly developed ultrasound transducer and a corresponding computer program, it proved possible to construct a three-dimensional (3-D) display--at 7, 9, 11 and 13 weeks of pregnancy, respectively--of three structures lying one inside the other: embryo, amniotic sac and uterus. By means of a special computer technique the three structures could be displayed both in relation to one another and singly. Spatial rotations of the reconstructed body can be displayed on the video screen as can the individual bodies in different cross-sections. With narrow angles between individual sections this method may become important in the intra-uterine diagnosis of malformations and also of neoplasms.

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A new method of three-dimensional (3-D) reconstruction of 2-D ultrasound images of the kidney is described. It is based on a coordinated spatial reconstruction of sequential cross-sectional images. The ultrasound head is moved longitudinally between two rails (parallel sections) and rotated. With a suitable computer program and contouring of each cross-section (so that the organ limits are defined for the computer) these cross-sectional pictures can be reconstructed into 3-D organ images. The kidney can then be presented spatially either as a binary picture or with closed surface. Ultrasound investigators are still unaccustomed to colour reproduction of 3-D reconstructed organs. It remains to be seen whether the method is valuable in routine clinical use.

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In the study reported here three-dimensional sonographic imaging of organs was achieved for the first time. To make this possible it was first necessary to ensure, by appropriate guidance of the probe, that the sequence of sonographic sections was coordinated in their spatial arrangement. This was accomplished by constructing a probe guide with which parallel sonographic sections could be demonstrated. The distance between these sections was known, so that with the aid of suitable computer programs three-dimensional reconstruction of a kidney examined in a water bath was possible. Since, however, due to the uneven surface of the body, it will hardly be possible to obtain parallel sonographic sections of an organ, a new solution had to be found to ensure the necessary coordinated sequence of sections. The solution lay in rotating the probe. A further device was constructed in which the probe could be rotated farther, by known angles, from section to section. The pivotal point was at the center of the probe tip. The computer knew the angular distance between these sections and reconstruction to a three-dimensional image was therefore possible. Prior the three-dimensional reconstruction the ultrasonographic sections had to be contoured, since only the surface of the organ was available for three-dimensional image construction. Three-dimensional imaging of an organ can be achieved on the one hand by binary representation and on the other with a continuous organ surface. The advantage of binary representation is that the original sonographic data are incorporated in the image-producing process without any computer manipulation; with a continuous surface the distance between the individual sections has to be interpolated.(ABSTRACT TRUNCATED AT 250 WORDS)

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