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Biomedical subjects

C Sohn

Publications and source records attributed to C Sohn.

At least 91 records · Page 5Linked to original sources
PubMed1992

[Palliative laser therapy in gynecologic oncology].

Local recurrences of carcinomas of the breast and genitals are a severe psychic and physical strain on the patients. Continuous confrontation with an often visible and generally painful tumour manifestation is an indication for palliative treatment, if other oncological therapies can no longer be employed. In these cases, the possibility of laser use represents a new therapeutic approach. In a pilot study at the University of Heidelberg, Department of Obstetrics and Gynaecology, a palliative laser therapy was performed on 45 patients with locally recurrent carcinomas of the breast (n = 29) and genitals (n = 16). Carbon dioxide and Nd:YAG lasers were utilized for tumour resection, vaporisation and coagulation. This new concept, the combined application of both wavelengths has been proved to be most efficient.

Adult↗
PubMed1992

[Diagnosis of tubal function using intraluminal ultrasound--initial results].

The extremely small ultrasound transducers of the intraluminal ultrasound instruments, introduced via catheters, enable diagnosis to be made inside hollow organs. In order to test the possible uses and indications for this new method in gynaecology, we conducted preliminary examinations in the diagnosis of the uterus and tubes. We employed an intraluminal instrument supplied by Dornier. The intraluminal transducers of this instrument have a diameter of 3.5 and 5 F. Following in-vitro examinations, hysteroscopy and laparoscopy/laparotomy were performed in 15 patients during which the transducer was pushed up via the cervix uteri to the tubes with full vision. This was successful in all 15 patients; in 9 cases the transducer could be pushed as far as the distal end. The tubal walls were examined in detail by this method and for the first time it became possible to achieve functional diagnosis of the motility of the tubes. Strictures can be visualised. The endometrium of the uterus, however, cannot as yet be diagnosed exactly by the present-day state of examination technique. If image quality can be further improved, this method will be the first to enable a functional diagnosis of the tubes and the uterus.

Endometrium↗
PubMed1992

[Ultrasound diagnosis of fetal lung maturity--a new method].

First results are presented to determine the maturity of fetal lung by sonography. Using the fetal liver as a reference-organ we are avoiding the known pitfalls which made it impossible in the past to standardize the fetal lung changes depending on the age of gestation. We examined 104 patients between week 27 and week 41. In one ultrasound section cut we depicted as well lung and liver. According to the known A-mode we registered frequencies in both organs. The registered frequencies were entered digitally into a computer and checked for f(mean), f(max) and f(min). Afterwards the frequencies of the lung were divided by those of the liver. Of all weeks of gestation the mean value and standard deviation were calculated. We found the liver as an adequate reference-organ, since there is no change of the reflection pattern between the different weeks of gestation, while there are significant changes to be registered in the fetal lung, a cutting line being week 35. A quotient of f(mean) lower than 1.1 hints to lung maturity while values over 1.1 point to immaturity. This was confirmed by several cases of analysis of amniotic fluid (L/S-ratio). Further comparisons with amniotic fluid results will have to validate these findings.

Amniocentesis↗
PubMed1992

[Doppler ultrasound study of breast tumors using color Doppler ultrasound, duplex ultrasound and the CW Doppler ultrasound].

The preoperative examinations by doppler-sonography of 83 patients with tumors of the breast are presented. The examinations are done with newest technique: duplex-sonography in slow-flow-technique (AI 3200, Dornier); colour-sonography in MEM-technique (AI 5200, Dornier) and synchronical colour-doppler++ (Quantum 2000, Siemens) and CW-doppler-sonography (Vasocope 3, Kranzbühler). There is a markable difference between the side of carcinoma and the normal side as well as pre- and postmenopausal patients. No difference is shown in cases of benign tumors and the normal side. The increasing blood flow of a malignant tumor is showed in changing the doppler parameters (A/B-ratio and resistance-index) and in the doppler wave form. The number of vessels found in or around a tumor is not a good criteria to find malignant diseases, the best criteria is the difference between sides of the mamma.

Blood Flow Velocity↗
PubMed1991

Diagnosis of fetal lung maturity by ultrasound: a new method and first results.

The first results are presented of a method to determine the maturity of fetal lung by sonography. By comparing the frequency characteristics of lung echoes to those from the fetal liver as a reference organ, we avoid the known pitfalls which previously made it impossible to standardize fetal lung changes with gestation. We examined 222 patients between 27 and 39 completed weeks of gestation. In one ultrasound section we depicted fetal lung and liver simultaneously. Switching to A-mode we registered the frequencies contained in the video envelope in both organs. The registered frequencies were entered digitally in to a computer and checked for mean frequency, maximum frequency and minimum frequency. Afterwards, the ratio of the frequencies of the lung and liver were obtained. For all weeks of gestation, the mean value and standard deviation were calculated. We found the liver to be an adequate reference organ, since there is no change of the reflection pattern between the different weeks of gestation, while significant changes were registered in the fetal lungs. A quotient of Q(mean) lower than 1.1 suggests lung maturity, while values over 1.1 point to immaturity. This appeared to be confirmed in 13 patients who had agreement between amniotic fluid lecithin values and Q(mean). Further comparisons with amniotic fluid results will have to validate these findings.

Journal Article↗
PubMed1991

[Differences in blood flow in maternal blood vessels in normal pregnancies and gestosis].

Clinical studies showed a lower blood flow in renal und uterine vessels in gestotic pregnancies. A comparison was therefore made between three maternal vessels (uterine, renal und thyroideal vessels) in normal and gestotic pregnant and non-pregnant women to show if the higher vessel resistance in gestotic pregnancies is a local or systemic event. There was a significant difference between the collectives in the blood flow of renal and uterine vessels, but no difference between the resistance in thyroideal vessels. The difference in the blood flow of renal vessels was higher than the difference in uterine vessels in the pregnant women. The increasing resistance, therefore, seems to be a local event at the beginning of the gestotic pattern of signs and symptoms. The higher resistance in the renal vessels allows, the conclusion that the kidney might be the important organ in the origin of the gestotic pattern of signs and symptoms.

Adult↗
PubMed1991

[Three-dimensional ultrasonic diagnosis in gynecology and obstetrics].

Three-dimensional reconstruction of an organ requires a coordinated sequence of cross-sectional scans. In ultrasound this can be solved by rotating the scan plane horizontally or vertically. Two scan heads have been built, one to rotate the plane around a horizontal, the second around a vertical axis. There are two ways to reconstruct the scans taken by ultrasound into a three-dimensional image: --to contour the surface of the organ in each scan and to reconstruct these contours to a ring-shaped structure. This procedure needs a lot of time; moreover, contouring must be performed via cursor on the screen. --calculate a transparent image of the organ. To obtain the best spatial image by the "transparent method", the image must be moved on the screen. Both methods of reconstruction are shown and compared in this paper. First experiences show that they can be applied in tumour diagnostic and in the diagnosis of malformations in early pregnancy. Further clinical studies will have to prove this.

Breast Neoplasms↗
PubMed1991

[Sonographic diagnosis of fetal lung maturity--a new method].

First results are presented to determine the maturity of fetal lung by sonography. Using the fetal liver as a reference-organ we are avoiding the known pitfalls which made it impossible in the past to standardize the fetal lung changes depending on the age of gestation. We examined 104 patients between week 27 and week 41. In one ultrasound section cut we depicted as well lung and liver. According to the known A-mode we registered frequencies in both organs. The registered frequencies were entered digitally into a computer and checked for f mean, f max and f min. Afterwards the frequencies of the lung were divided by those of the liver. Of all weeks of gestation the mean value and standard deviation were calculated. We found the liver as an adequate reference-organ, since there is no change of the reflection pattern between the different weeks of gestation, while there are significant changes to be registered in the fetal lung, a cutting line being week 35. A quotient of f mean lower than 1.1 hints to lung maturity while values over 1.1 point to immaturity. This was confirmed by several cases of analysis of amniotic fluid (L/S-ratio). Further comparisons with amniotic fluid results will have to validate these findings.

Female↗
PubMed1991

[Improvements in 3-D ultrasonic imaging].

The problem of gaining a coordinated sequence of section cuts by ultrasound is solved by rotating the plane section around a vertical and a horizontal axle. There are two possibilities in presenting the 3D image of the examined organ: ring structure image or transparent image. Precondition in the ring structure image is time consuming and defective since it has to be done by hand using a cursor. These pitfalls can be avoided when using a method without contouring by showing the 3D image transparently. Each section cut has to be calculated transparently. Both methods are presented in this paper and compared as to their applicability in medicine. The problem of the transparent 3D presentation lies in the fact that it cannot be well presented on printed paper, as is done her. The moving picture on the computer screen gives an optimal 3D image. This new method seem to be useful in tumor diagnostic and diagnostic of malformations in early pregnancies.

Computer Graphics↗
PubMed1991

[The effect of pregnancy and parity on the venous system of the leg].

Pregnancy is a risk factor for development of varicosis. The reason remains unclear. Because of the secondary diseases like thrombosis, pulmonary embolism and chronic cardial and respiratory diseases treatment of risk factors is important. Therefore we examined 54 patients with sonography and venous occlusion plethysmography before and immediately after delivery. Some of the patients could be reexamined one month and one year following delivery. All veins had a significant exaggerated distensibility post partum. Other functional parameters were not changed. In another study 50 primiparae and 50 multiparae before and after childbirth and 100 women between age 40 and 50 had been examined with light reflection rheography. Pregnancy per se had a negative influence on venous function. Phlebological status had to be included into prenatal care.

Female↗
PubMed1990

Current evaluation of sonography of the meniscus. Results of a comparative study of sonographic and arthroscopic findings.

Sonography of the knee has gained in significance in the diagnosis of the meniscus; experimental and clinical studies have demonstrated that the normal and pathological anatomy of the meniscus can be visualized on a sonogram. The aim of this comparative investigation is to evaluate sonographic lesion diagnosis in comparison with arthroscopic findings, using a standardized examination method. Two hundred and six knee joints were first scanned sonographically using a 7.5 MHz sector transducer. The examining doctor had neither anamnestic nor clinical information in advance. On the following day, the joints were examined arthroscopically, without the findings of the day before being available to the examiner. When the findings were compared, the sensitivity of sonographic diagnosis of lesions was found to be 82.2% and its specificity 87.6%. The patients were of varying ages and had varying anamneses. The results show that sonography of the meniscus is a valuable diagnostic help when the knee-joint symptoms are not clear, given that the correct technical equipment and sufficient experience with this form of examination are at hand. The advantage of sonography is that, in contrast to arthroscopy, it is noninvasive and easily available.

Adolescent↗
PubMed1990

[Endosonographic Doppler flow measurement of the embryonic and fetal umbilical cord].

The blood flow in the umbilical cord was examined via endovaginal Doppler sonography in 30 cases of early pregnancy. For the first time it was possible to examine by Doppler sonography the arterial blood flow in the completed 6th week of pregnancy p.m. With increased duration of gestation there was a continuous increase in arterial blood flow until establishment of a constant flow over the entire cardiac cycle with a constant presence of a diastole in the 14th pregnancy week. Venous blood flow also showed from the 7th pregnancy week p.m. onwards a constant development until attainment of a continuous Doppler flow profile in the 10th pregnancy week. Since the doppler curves of the same gestation period agree with one another, the Doppler profiles obtained in each case can be considered to be both typical and representative. The course of the Doppler flow curves shows the improving performance of the heart of the embryo in the direction of an increasing metabolic exchange between embryo and mature placenta via the increasingly efficient vascular systems.

Blood Flow Velocity↗
PubMed1990

[Ultrasound criteria of a meniscus lesion].

The tear in the meniscus interrupts the outline at which the sound-wave energy is reflected. This means that the sonogram shows an echo-rich, light reflection pattern. Degeneration also shows up as an echo-rich area, reflecting greater density of the tissue in the meniscus. This has been confirmed by experimental examination of knees of corpses, and also by clinical experience based on more than 2000 sonograms of the meniscus. A quota of more than 90% correct diagnoses can be obtained if the proper criteria are observed in case of a lesion of the meniscus, and if the technical equipment is adequate and the examiner has acquired sufficient skill.

Diagnosis, Differential↗
PubMed1990

[3-dimensional organ image using ultrasound].

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)

Animals↗
PubMed1990

[3-dimensional ultrasound image of the infant hip].

Clinical and experimental studies proved the usefulness of three-dimensional sonographic diagnosis by means of a newly constructed transducer providing for a coordinated sequence of cuts, and hence initial trials investigated its application in sonographic diagnosis of the infant hip. Differences were found in the three-dimensional anatomic image between normal and dysplastic hips. It is no longer necessary to draw any lines or to perform any calculations of angles as required in "conventional" hip sonography. In contrast to conventional hip sonography, the use of a sector transducer is meaningful with this method, since the drawbacks of the sector transducer stated by Graf, do not apply. Clinical studies will have to confirm the possible use of this new method in diagnosis disturbances in infant hip maturation.

Computer Graphics↗
PubMed1989

[3-dimensional organ representation with ultrasound. Experimental studies--computer simulation].

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.

Computer Simulation↗
PubMed1989

[Clinical application of 3-dimensional ultrasound display. Initial results].

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.

Amnion↗