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C Sohn

Publications and source records attributed to C Sohn.

At least 37 records · Page 2Linked to original sources
PubMed1997

[3-dimensional sonography in the diagnosis of meniscal lesions. An experimental and clinical study].

There is no consensus regarding the clinical significance of conventional two-dimensional ultrasound in the diagnosis of meniscal tears of the knee. Three-dimensional ultrasound spatially reconstructs a transparent image of subsequent ultrasound scans. In an experimental study of 96 menisci, radial and oblique tears were detected more often by three-dimensional ultrasound. In a clinical study of 60 menisci the two- and three-dimensional ultrasound reached a sensitivity of 92% and 100%, a specificity of 83% and 88%, a positive predictive value of 58% and 67%, and a negative predictive value of 98% and 100%, respectively. Altogether, there was no statistically significant difference between both methods. The high negative predictive value, however, shows that the three-dimensional ultrasound may be a clinically relevant examination for special questions in the diagnostics of meniscal tears.

Adolescent↗
PubMed1997

[Diagnosis of blood flow in breast tumors with increased blood pressure. New possibility in tumor field diagnosis].

On the assumption that the architecture of blood vessels of malignant tumors, formed by neoangiogenesis, shows characteristics that are different from those of blood vessels of benign tumors or physiological findings, we have tried in the present study to investigate the behavior of these different vessels under increased blood pressure. Using a special stand, the same sonographic section could be stably maintained during an examination time of approx. 4 minutes. Using a new computer program, the color pixels of the employed Angio color technique were quantified and recorded as a function of the measured blood pressure. To increase blood pressure, the patient had to press a hand grip, which practically always caused a systolic blood pressure elevation of more than 15-20 mmHg. Seventy patients with sonographically detected breast tumors were examined; 54 (14 benign and 40 malignant tumors) could be included in the evaluation. We found four typical types of curves: Curve type 1 is associated with an instantaneous increase in blood flow with increased blood pressure, followed by a drop in the blood pressure, with a slow decrease in blood flow as the blood pressure drops (with 29 malignant and 3 benign tumors). Curve type 2 shows a continuous increase in blood flow-though somewhat delayed with respect to the rise in blood pressure-which is also observed when the blood pressure drops (exclusively benign tumors). In curve type 3, maximum blood flow is reached after the blood pressure maximum, and then the blood flow decreases (1 benign and 3 malignant tumors). Curve type 4 features decreased blood flow in spite of increased blood pressure (3 benign and 5 malignant tumors). The described quantification method, in combination with the stand, permits for the first time analysis of a tumor under increased blood pressure as to its blood flow behavior over time in an examination using a challenge test. Here one can find two distinctive curve types (types 1 and 2) that correlate mostly with malignant (type 1) or benign (type 2) breast tumors. Should this tendency be substantiated by additional large-scale studies, it would seem that a new ultrasonic possibility for differential diagnosis has been found.

Adult↗
PubMed1997

Sonographic blood flow measurements in malignant breast tumors. A potential new prognostic factor.

BACKGROUND: The aim of this study was to find a possible relationship between the biological behavior of carcinomas of the breast and sonographically detectable blood flow after first studies showed a correlation between blood flow and prognostic factors. METHOD: 259 patients with ductal invasive breast cancer were examined using MEM (i.e., the Maximum Entropy Method), a new sonographic blood flow measurement technique capable of discerning considerably slower blood flow velocities than Doppler sonography. Due to the lack of objective methods for quantifying the blood flow, the findings were divided into three classes dependent upon the visual color information obtained. The blood flow was correlated with the size of the tumor, lymph node and receptor status, ploidy and S-phase fraction. RESULTS: Most of the patients with small tumors, without lymph node metastases, with positive receptors, with a diploid genome, and with a low S-phase fraction belonged to the group with the lowest blood flow. CONCLUSION: The close relationship between the established prognostic factors and the sonographic blood flow measurements using MEM might be indicative of a new preoperative prognostic factor; this must, however, be confirmed by larger studies.

Blood Flow Velocity↗
PubMed1997

The sensitivity of new color systems in blood-flow diagnosis. The maximum entropy method and angio-color-comparative in vitro flow measurements to determine sensitivity.

BACKGROUND: Two new blood-flow-diagnosis techniques have recently been developed as supplements to the established color techniques: the MEM (maximum entropy method) technique and color flow amplitude (power Doppler). These are capable of representing blood flow in distinctly more slowly flowing areas than is possible with the conventional Doppler technique. METHODS: Both methods make use of the Doppler technique in part, yet analyze the reflected signal in a different manner, in so doing optimizing the relation between the noise and the signal. Measurements were obtained on two anatomic flow models to test the sensitivity of both techniques under slow flow conditions. RESULTS: The slowest flow the MEM technique was capable of recording was 0.5 mm/s, albeit utilizing a 5-MHz transducer for the MEM technique and a 10-MHz transducer for the angio technique. One may thus assume that the MEM technique would be still more sensitive when utilizing a 10-MHz transducer. The advantage of the MEM technique is its real-time flow representation: The angio technique requires a few seconds of acquisition time. This could have serious consequences during clinical utilization. Doppler sonography was merely capable of detecting a minimum flow velocity of 15 mm/s. The angio technique is less dependent on the angle during flow representation than the MEM technique. CONCLUSIONS: The distinctly higher sensitivity of these two new color techniques offers new possibilities in the clinical sector as far as the perfusion diagnosis of organs and tumors is concerned.

Angiography↗
PubMed1997

Telencephalosynapsis (synencephaly) and rhombencephalosynapsis with posterior fossa ventriculocele ('Dandy-Walker cyst'): an unusual aberrant syngenetic complex.

Agenesis of the cerebellar vermis (paleocerebellar agenesis) with fusion of the cerebellar hemispheres (rhombencephalosynapsis) is a rare malformation of the central nervous system (CNS). Its combination with synencephaly (telencephalosynapsis), telencephalic ventricular aplasia, aqueductal atresia and cystic fourth ventricle has not yet been described, as far as we know. Here, we report this combination in a 23-weeks' gestation male fetus who was aborted to a 24-year-old diabetic mother. In this fetus with cerebral and cerebellar hemispheric fusion, vermian agenesis was associated with a Dandy-Walker-like posterior fossa cyst, in spite of the fusion of the hypoplastic cerebellar hemispheres. The CNS malformations were further accompanied by dysmorphic facial stigmata such as unilateral atresia of the external ear, ocular hypertelorism and a broad nasal bridge. Preaxial polydactyly and contractures of the upper limbs were the only associated non-cranial abnormalities. Cytogenetic studies revealed a numerically and structurally normal male (46, XY). The malformation complex described in this fetus of a mother with antedating pregnancy diabetes appears to represent a previously undescribed aberrant syngenetic CNS phenotype, some basic teratogenetic aspects of which will be discussed in this paper.

Adult↗
PubMed1997

[Cardiotocographic changes after umbilical cord puncture and umbilical cord transfusion].

In connection with umbilical cord punctures and transfusions the degree of pathology still tolerable after these procedures as well as the influence on subsequent obstetric management has to be discussed. In a prospective study we evaluated 98 cordocenteses with (n = 44) and without (n = 54) transfusion (25-37 week of gestation). 30-160 ml of blood were transfused. In all cases the umbilical vein was punctured at the point of insertion into the placenta (46x posterior and 52x anterior wall placenta). A CTG was performed prior and after the punction and was evaluated according to the Fischer score. After the procedure, the course of pregnancy was normal in all puncture patients and in 52 of 54 patients who also underwent a transfusion. Because of a pathological CTG due to a severely hydroptic fetus, a caesarean section had to be performed in one woman seven hours after umbilical cord transfusion. In another patient an emergency section was necessary immediately after the umbilical cord transfusion, due to persistent fetal bradycardia. In the puncture group mean Fischer score values decreased from 9.1 to 7.5, in the transfusion. In another patient an emergency section was necessary immediately after the umbilical cord transfusion, due to persistent fetal bradycardia. In the puncture group mean Fischer score values decreased from 9.1 to 7.5, in the transfusion group from 8.6 to 7.4. The results were more unfavorable when amplitude and occurrence of accelerations were considered, especially in the transfusion group. In one fifth of the puncture cases and one fourth of the transfusion patients the criterium of baseline crossings improved after the procedure. In summary, a pathological CTG is to be expected after umbilical cord punctures and transfusions, with however, only the necessity of surveillance. Only in cases of persistent fetal bradycardia an active obstetric management is indicated.

Blood Transfusion, Intrauterine↗
PubMed1997

[Telecommunication--a medium for improving prenatal diagnosis and gynecologic ultrasound diagnosis? Initial experiences].

To establish the requirements for real-time transfer of an ultrasound examination via telecommunication network the following tests were performed: The ultrasound data were transferred from the video out of an ultrasound system to a basis terminal of the German Telekom. Simultaneously, an external video camera filmed the positioning and movements of the ultrasound transducer, and the verbal comments were recorded. These informations were transmitted to Karlsruhe and London, where they were rerouted to the examination room in Heidelberg. Here the informations were received on a Telecom reception unit/terminal and compared directly with the initial signal. The quality was sufficient if the moving ultrasound images and the camera image of the transducer as well as the oral comment were transmitted over 2 parallel ISDN lines. The delay to a real-time transmission of the examination process is only in the range of milliseconds. If only one ISDN line is used, the image quality is unsatisfactory, three parallel lines do not bring significant improvement of image quality. Telemedicine seems a new possibility to bring the knowledge of specialized centers to the practicing gynaecologists thus avoiding unnecessary referrals. Still unanswered, however, are the problem of liability, data protection and costs.

Adult↗
PubMed1997

[Hygroma colli (cervical neck edema) as an ultrasonographic parameter of fetal chromosome anomalies].

A two year retrospective study of 57 women with fetal hygroma colli between 2 and 15 mm was carried out at the University Women Hospital in Heidelberg. In this study maternal age, week of gestation, thickness of the nuchal oedema and the genetic results of amniocentesis were documented. Chromosomal abnormalities were found in 20 cases (35%), monosomy X in eleven, trisomy 21 in five and trisomy 18 in four. No connection between an individual syndrome and a particular week of gestation could be found. An increase of the thickness of the nuchal oedema showed a significant correlation to the incidence of aneuploidies. Chromosomal abnormalities were not observed in cases of less than 3 mm thickness (0/5). Between 3 and 4.9 mm one abnormal karyotype (4 mm) was found (1/18) whereas in the group of 5-6.9 mm approximately one third (6/15) of all fetuses showed chromosomal abnormalities. Aneuploid karyotypes were found in two thirds of cases (14/20) with a fetal nuchal translucency of 7 mm and more. Surprisingly, a correlation between maternal age and incidence of fetal chromosomal abnormality could be seen, but it was not significant. While a chromosomal aberration could be connected to age in 50% of mothers under the age of 25 and over 34, only a third of women aged 25-29 and only one fifth aged 30-34 showed chromosomal abnormalities in combination with hygroma colli. Our results confirm the recommendation of previous studies for extensive ultrasound examination during the first and second trimester in order to improve early detection of fetal chromosomal abnormalities particularly in women not normally covered by the age-related indication for amniocentesis.

Adult↗
PubMed1997

[Doppler score for evaluating perinatal risk].

Doppler sonography now has a definite place in the surveillance of risk pregnancies. Uniform clinical management is sometimes difficult especially in borderline cases. The following study demonstrates the possibility of standardizing and systematizing Doppler results using a score. In a collective of 253 pregnant women we performed Doppler examinations in the fetal aorta, umbilical artery, middle cerebral artery, internal carotid artery. The results were divided into 4 groups and correlated to the fetal outcome. There was a highly significant worsening in prognosis regarding duration of pregnancy, birth weight and rate of cesarean sections with increasing Doppler score. In the event of pathological and highly pathological scores, the average duration of pregnancy was 23 and 48 days shorter than normal. As a result, there was a highly significant reduction in the average birth weight compared to fetuses with normal Doppler scores: by 1060.7 g in the case of a pathological score and by 1633.5 g in the case of a highly pathological score. There was a highly significant correlation concerning the rate of cesarean sections and the indication "fetal distress". The average interval between diagnosis and birth was 6.3 days in the case of pathological Doppler findings and 2.3 days in the case of highly pathological findings. The difference was highly significant. In the case of highly pathological scores all fetuses were delivered after at least 5 days, compared with after at least more than 10 days in those with only pathological Doppler findings. This reflects the fact that there is none room for discretion in case of a highly pathological flow. In summary the Doppler score allows better estimation of fetal risk and can improve fetal prognosis by special monitoring and earlier obstetric intervention.

Birth Weight↗
PubMed1997

[Increased AFP in maternal serum as an indication for invasive diagnosis].

The association of increased maternal serum alpha-fetoprotein levels (MS-AFP) with certain morphologic anomalies of the fetus is fully established. These anomalies are abdominal wall defects (e.g. omphalocele, gastroschisis, complete eventration), neural tube defects (anencephalus, spina bifida, encepalocele) and other malformations (e.g. coccygeal teratoma). The present study compares MS-AFP levels with amniotic fluid alpha-fetoprotein (AF-AFP) and acetylcholinesterase activity, the results of ultrasound, genetic and morphologic examination. Between April 1992 and November 1995 60 patients were referred to our clinic for further diagnosis after detection of elevated MS-AFP. After an ultrasound examination was carried out amniocentesis (AC) was performed in 54 cases, AC + placentesis (PC) in 3 patients and PC only in 3 cases with anhydramnion. Mean maternal age was 29 years (range 20-37 years). Punction was performed at a median of 19 + 1 weeks of gestation (15 + 2-23 + 2 weeks of gestation). MS-AFP, AF-AFP and acetylcholinesterase activity was measured. MS-AFP and AF-AFP were given as multiples of the median (MoM). Values < or = 1-2.0 MoM were considered normal. Elevated levels were defined to be greater than 2 MoM. In all cases the chromosomal finding was normal or norm variant. Sonographical anomalies were detected in 7 fetuses (3 cases with spina bifida, 1 case with omphalocele and 3 cases with abdominal wall defects in connection with other malformations). All sonographic diagnoses were confirmed post partum. The MS-AFP varied between 0.9-6.0 MoM. In 7 cases MS-AFP previously (referring center) evaluated as increased was found to be within normal range in our department. This cases included normal values were found in 30 cases and 25 findings were pathological. 2 out of 7 structurally abnormal fetuses had normal values, 5 of them had elevated MS-AFP. In the group of normal fetuses the highest MS-AFP we found was 6.6 MoM. In the AC-group the AF-AFP ranged between 0.7-8.7 MoM, it was within normal range in 50 and pathological in 8 cases. In the group of fetuses without structural anomalies the highest AF-AFP was 7.5 MoM. In the group of fetuses with structural anomalies the AF-AFP values were 1x normal and 3x pathological (> 3.5 MoM). Acetylcholinesterase activity in the amniotic fluid was negative in 51 cases, positive in 4 cases and faint positive in 2 cases. In all fetuses with structural anomalies in which an AC could be performed, acetylcholinesterase activity was positive. On the other hand we found only 1 of the structurally normal fetuses with positive acetylcholinesterase activity. Elevated MS-AFP and AF-AFP may be an indicator for morphological anomalies. Yet there were many positive results without any sonographical findings. The determination of a positive acetylcholinesterase activity in the amniotic fluid is more specific. All malformations have been detected by ultrasound examination before the results of the AF-AFP were available.

Abdominal Muscles↗
PubMed1996

[Sensitivity of new color systems: "maximum entropy method" and angio-color. Comparative in vitro flow measurements].

AIM: The sensitivity of the two procedures for slow blood flow velocities in two flow phantoms examined and compared to conventional colour Doppler. METHOD: In two phantoms with vessels between 0.3 and 6 mm diameter the slowest measurable blood flow with the different techniques was determined. The influence of various application angles was also studied. RESULTS: The slowest blood flow velocity detected with the MEM technique was 0.6 mm/s and with the angio-technique 0.4 mm/s. Two different scan-heads were used; a 5 MHz probe for the MEM procedures and a 10 MHz probe for ultrasound angiography. Using a 10 MHz scan-head will most likely lead to increased sensitivity of MEM. Blood flow representation with the MEM technique is real-time, while several seconds of acquisition time are required for the angio-technique, which is a disadvantage during clinical use. Conventional Doppler was merely able to represent 15 mm/s blood flow. The angio-technique was less dependent on the application angle than the MEM procedure. CONCLUSION: The definitely increased sensitivity of the two colour methods open up new areas in the diagnosis of organ and tumour perfusion.

Blood Flow Velocity↗
PubMed1996

[Experimental study of meniscus lesions. Significance of 3-dimensional ultrasonography].

AIM: The clinical value of two-dimensional ultrasound in examining the menisci of the knee compared to other methods is controversial. We studied the utility diagnosed by three-dimensional sonography in evaluating meniscal tears. METHOD: 96 menisci with standardised artificial lesions were examined in a bath of Ringer solution. Two-dimensional ultrasound was compared to three-dimensional ultrasound, which creates three-dimensional reconstruction of sequential ultrasonographic images. RESULTS: The three-dimensional ultrasound had a higher sensitivity of 88% vs 69% with a specificity of 83% vs 94% for the diagnosis of meniscal tears compared with the two-dimensional method. The sensitivity in imaging was 54% in each case for longitudinal tears, 63% vs 96% for horizontal tears, 67% vs 37% for oblique tears and 54% vs 0% for radial tears. The difference of these results, however, was not statistically significant. Radial tears were more frequently diagnosed by three-dimensional sonography. CONCLUSION: In our model, sonographic diagnosis of meniscal tears was improved only partially by using three-dimensional ultrasound. Whether in vivo other factors alter the minimal differences between the two techniques is the subject of ongoing investigation.

Humans↗
PubMed1996

[The clinical value of Doppler ultrasound in obstetrics].

Doppler sonography now has many indications in obstetrical diagnosis. Its wide and often uncritical application was the reason for our study group to confirm its importance. Moreover, we wanted to prove our own procedure. We made 950 Doppler examinations in a group of 449 pregnant women and correlated the results to the fetal outcome. Children with pathological Doppler findings showed a significantly lower birth weight of 599 g, a significantly lower duration of pregnancy of 6 days, a significantly higher rate of Caesarean sections and a significantly higher death rate compared to children with normal Doppler findings. Concerning Apgar- and pH-values there was not any significant difference between the two collectives. These results show that fetuses with pathological Doppler values or growth retardation can have the same prognosis as fetuses with normal Doppler findings if they are recognized and monitored at an early stage. The morbidity by acidosis can thus be reduced.

Acid-Base Equilibrium↗
PubMed1996

[Laparoscopy in (apparently) benign ovarian tumors between benefit and catastrophy and the deceptive safety of laparoscopic lap sacs].

Endoscopic ovarian surgery is currently spreading tremendously, but also rather uncritically. The technical possibilities both of organ preserving and ablative endoscopic surgery are controversial, so that structuring of the indication for an endoscopic procedure as well as optimization of the endoscopic removal of ovarian tumor or adnexae is of utmost relevance. Therefore, a study was performed at the Department of Obstetrics and Gynaecology of the Heidelberg University with the following aims: Risk evaluation of operating into an ovarian malignancy at endoscopy for "presumably" benign cystic ovarian tumors in n = 100 cases in Heidelberg and literature survey Analysis of problems and complications during clinical application of laparoscopic lap sacs for removal of cystic adnexal tumors or adnexae (n = 50) Experimental examination of the risk of an endoscopic lap sacs to rupture during a procedure The risk of endoscopically operating into an ovarian cancer lies between 0.4 and 3% according to literature data. Despite maximal preoperative selection, mainly by ultrasound examination, in our group of 100 patients, in three women without preoperative signs of malignancy but with discreet intracystic structures in the ultrasound, an endoscopic adnexectomy with complete removal in a lap sac was performed, and though immediate section for microscopic examination was negative, final histology revealed one ovarian cancer la and 2 borderline tumors, same stage. In the time period analyzed, three further patients were referred to our center for secondary, delayed (median 3 months) staging after endoscopic procedures for presumed benign lesions. Clinical application of lap sacs proved the necessity of an intensive training. In 3 patients an intraperitoneal rupture of the sac occurred. Typical problems were volume discrepancies between sac respectively abdominal incision and tissue to be removed (28% of cases). The risk of rupture of the various lap sacs examined differed significantly (p < 0.05). Due to the complex pathological nature of cystic adnexal tumors, a 100% selection for the endoscopic approach is not feasible. Therefore, an endoscopic procedure should only be performed after optimal preoperative diagnosis and, in case of the slightest doubt, only if intraoperative microscopic examination is available, and the possibility to perform an immediate staging laparotomy. Sufficient information of the patient is relevant. Laparoscopic removal of tumor or adnexae should be performed in a lap sac. However, there is no absolute certainty of preventing spillage even with the lap sac, since not all endoscopic sacs available are of a sufficient quality.

Adult↗
PubMed1996

[Possibilities of laparoscopic ultrasound diagnosis].

Both pre-operative transvaginal sonography and laparoscopical diagnosis leave gaps in the diagnosis of adnexal tumors. The combination of both methods seems to fill these gaps. For diagnosis with Laparoscopical Sonography a special scan head is needed: After removing the optical components there was a little linear-array installed into the original gastroscope with a diameter of only 9 mm which enables maximum flexibility during examinations. The linear-array consists of 128 crystals with a frequency of 7.5 MHz (penetration depth: 6 cm), enabling B-Image Sonography, Pulsed and Color Doppler as well as Angio-Color-Technique. Laparoscopical Sonography in addition to transvaginal and transabdominal sonography leads to progress in diagnosis and therapy. As the scan head can be placed directly in front of the area which is normally hardly detectable diagnosis is possible and plannings for the further operations as well as color-doppler controls during operations can be improved. In several cases this method allowed detection of metastases of the liver which were not visible by transabdominal ultrasound.

Equipment Design↗
PubMed1996

[What is the reliability of conventional ultrasound mammography and color coded ultrasound in diagnosis of breast tumors?].

To establish the diagnostic relevance of sonographic blood supply measurement for tumor's nature evaluation, 192 women with suspect unilateral breast findings were examined on the preoperative day with color coded sonography (MEM color technique). A combination of evaluation in B-scan and color mode resulted in a sensitivity of approx. 96% in cases of malignant tumors (121 histological findings of breast cancer). Specificity in the 71 patients with a histologically benign diagnosis was of over 90%. Despite an essential improvement in dignity diagnosis, histologic proof is, however, necessary, even in cases of benign findings at the diagnosis. Since a 100% certainty in the differentiation of benign and malignant tumors will never be achieved with ultrasound techniques, biopsy specimen will have to be taken. Thus additional measurements of tumor blood flow seems of no clear advantage for the patient. In our opinion, the essential contribution of blood flow diagnosis of malignant tumors lies rather in the evaluation of tumor prognosis, since the differences in the blood supply of malignant growths are indicators for their biological behavior.

Adult↗
PubMed1996

[Diagnostic value of Doppler ultrasound in evaluation of breast tumors].

Angiogenesis is an essential condition for tumor growth. Therefore, it seems to be of interest to prove if blood flow and vascularization of breast tumors give information concerning their dignity. Consequently, 205 patients with palpable and/or mammographically detected breast tumors were examined prior to surgery by doppler sonography for blood flow in the area of the tumor. In 174 patients of this group the corresponding area of the contralateral breast was also screened by doppler ultrasound. With third doppler generation angiodynography tumors can be visualized as B-images with simultaneous information on vascularization. An integrated doppler system shows the detected blood flow in form of a doppler curve, also allowing quantification according to doppler criteria (Resistance Index RI). Blood flow detection in the tumor itself was successful in 71% of all malignancies, whereas in only 6.6% of the 76 benign lesions (n = 5) blood flow was found in the central tumor area. In the area surrounding the tumor blood flow was detected in 83% of all carcinomas, but only in 29% of benign findings. Blood flow could be detected significantly higher in malignancies than in benign lesions (p = 0.003). Blood flow detection in the tumor itself was a highly specific (93%) method of discrimination between malignant and benign breast tumors. Further quantification by means of doppler parameters only increases insignificantly specificity, quantification of blood flow in the area surrounding the tumor using the RI and the comparison with the contralateral breast could improve the diagnostic value as our findings RI < 8 for benign vs. > or = 8 for malignant lesions demonstrated. Detection of malignant tumors showed a sensitivity of 80%, a specificity of 90%, and a positive predictive value of 93%. In patients with breast cancer (histologically confirmed) the detection rate of blood flow in tumors and surrounding areas was independent of tumor size or nodal status.

Blood Flow Velocity↗