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Biomedical subjects

C Sohn

Publications and source records attributed to C Sohn.

At least 55 records · Page 3Linked to original sources
PubMed1995

Initial results of intraluminal ultrasound in gynecologic diagnosis.

The interior of hollow organs can be examined using extremely small intraluminal ultrasound transducers inserted into catheters. We tested the practicality of this method and the range of indications for which it could be useful in gynecology by performing initial examinations of extirpated uteri and fallopian tubes. In vivo, we inserted an intraluminal unit with transducer diameters of 3.5F and 5F through the cervix into the fallopian tubes of 15 patients during hysteroscopy or laparoscopy. The catheter was inserted successfully into the tube in all 15 women, and in 9 all the way to the distal end. The tubal wall was identified precisely, and a functional diagnosis of tubal motility was established for the first time. However, it was impossible to differentiate between tubal epithelium and muscularis. Also, uterine endometrium cannot be evaluated accurately with the current level of technology. This technique will enable the first functional examination and diagnosis of the tubes and uterus, provided that further improvements can be made in the quality of the images.

Catheterization↗
PubMed1995

Differential diagnosis of mammary tumors with vocal fremitus in sonography: preliminary report.

During sonographic examinations using the new color Doppler technique, maximum-entropy method (MEM), it was discovered, by chance, that artefacts which are produced by vibrations of the thorax can be used to differentiate between malignant and benign breast lesions. These artefacts, in the form of small color pixels, can either be brought about by vocal fremitus known from internal medicine or by humming in a low tone. In the case of malignant tumors, the color pixels are visible in the middle of the sonographically portrayed tumor as well as in the surrounding tissue, whereas in benign tumors the artefacts are only found in the surrounding tissue and are quite clearly not present in the center of the tumor. On the preoperative day, 95 patients with 46 benign and 49 malignant lesions were examined using the method described above. In 91% the differential diagnosis was in accordance with the histological results. In seven cases a benign lesion was classified before the operation as malignant and in two cases malignancy was incorrectly diagnosed as benign. Our explanation of the phenomenon is based on the fact that most benign tumors exhibit a restricted growth and form a clear-cut boundary with the surrounding tissue, so the vibrations are not conducted into the tumor. In contrast, malignant lesions grow by infiltrating the surrounding tissue, allowing the vibrations to be conducted into the tumor, where they can be demonstrated as small color pixels.

Artifacts↗
PubMed1995

[Initial experiences with laparoscopic intraoperative ultrasound].

Preoperative ultrasound as well as intraoperative laparoscopic diagnosis have both their limits, a fact that might be significant for laparoscopic surgical management. In particular, since in this surgical domain, where almost everything has become technically feasible, the operator must decide what is to the benefit of the patient. A possible solution could be laparoscopic ultrasound, i.e. ultrasound diagnosis per laparoscopy at the very site of the lesion. The advantages are evident. Due to the closeness to the organ to be examined, the frequency of the scan head can be extremely high, resulting in better resolution. Also, structures could be visualized by ultrasound which e.g., due to adhesions cannot be seen with the laparoscope. Moreover, ultrasound offers a view into the structures which can be seen only from the exterior with the laparoscope. To perform these examinations we used a specially designed scanhead (Toshiba): Instead of the optical system a crystal array was inserted into a conventional gastroscope. The result was a high resolution 7.5 MHz linear array at the distal end of a freely movable gastroscope. Colour doppler sonography is feasible with this scanhead. We examined 19 patients, 16 of them with ovarian tumours, and attempted visualization of the uterine myometrium/endometrium as well as of the liver. In six cases of ovarian tumours in which only cystic structures were found by preoperative transvaginal sonography, laparoscopic ultrasound additionally revealed solid inner structures. In 5 cases direct laparoscopic view of the ovarian lesions was impossible due to severe adhesions. They were, however, easily detected by intraoperative ultrasound.(ABSTRACT TRUNCATED AT 250 WORDS)

Equipment Design↗
PubMed1995

[Ultrasound blood flow measurement in malignant tumors is a possible new prognostic factor].

OBJECTIVE: The aim of the present study was to find a possible relationship between biological behavior of breast cancer and sonographically detectable blood flow. METHODS: 157 patients with ductal invasive breast cancer were examined by means of a new sonographic procedure, the MEM (Maximum Entropy Method), able to detect considerably lower blood flow velocities than doppler sonography. In the absence of objectifyable quantification methods, findings were allotted to 3 classes, depending on the visual color information obtained. Blood flow was correlated to tumor size, lymph node and receptor status, ploidy and S-phase-fraction. RESULTS: Most patients with small tumors, no lymph node metatases, positive receptors, diploid genome and low S-phase found to have low blood flow. CONCLUSION: This close relation between established prognostic factors and results of sonographic blood flow examination with the MEM might indicate a new preoperative prognostic factor, which, however, will have to be proven by larger studies.

Biomarkers, Tumor↗
PubMed1995

[Initial experiences with a new color technique: ultrasound angiography].

The sonographic diagnosis can be expanded by Color Doppler. Nevertheless something is missing, especially concerning the demonstration of the very slow velocities as it can be found in neovascularized malignant tumors. A recently developed new color technique--the Angio-Color of the Diasonics Corporation, Sonotron (other companies have prototypes of this color)--promises to improve the detection of very low flow velocities. Due to a method very different to the conventional Doppler technique the registered signal is coded in the color image of the blood flow: that means that the amplitude and not the frequency shift is coded in color. Therefore there is less noise in the color mode with the possibility of showing the lower flow in comparison to the conventional Doppler. In Gynaecology and Obstetrics the advantages in the demonstration of the placental blood flow were obvious. In eutrophic fetuses the blood flow could be registered over the whole breadth of placenta, while in dystrophic fetuses this was possible only at the margin of the placenta with some color pixels in the middle of the organ. The conventional Color Doppler was not able to show the flow in the placenta even in eutrophic fetuses. Also the flow in fetal organs produced different results using both methods. So the angio-technique showed more color pixels in the periphery. In 8 malignant breast tumors both methods were able to show blood flow, but the Angio-Color showed more color pixels as the conventional color did.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1995

[Possibilities and limits of a new color technique: ultrasound angiography--results of the "Heidelberg Round Table Discussion"].

Sonographic diagnostics has been essentially enlarged by blood flow measurements with the color Doppler technique. Nevertheless, the method has certain limitations, especially when employed to visualize extremely slow blood flow velocities, which occur e.g. in malignant tumors due to neovascularization. Recently, a new technique, the so-called angio-color procedure, has been presented, which is supposed to overcome the above-mentioned limitations. The way of coding the signal differs considerably from that in conventional color Doppler: The amplitude is color coded, not the frequency deviations. Results and first experiences with the new procedure in various domains were discussed at a 'Heidelberg Round Table' and are summarized in the present article. In the obstetrics/gynecology there are clear advantages in the representation of blood flow in the placenta. In eutrophic fetuses a blood flow over the entire placental breadth was detected, in dystrophic fetuses, however, only on the margins of the placenta. Conventional color Doppler could not visualize blood flow in the placenta at all. Blood flow assessment in the fetal organs also provided different results with the two procedures: the angio-color method showed color pixels even in the peripheral areas. In 8 malignant breast tumors the same observation was made, the angio-color procedure seemed to visualize more color pixels. In 4 of 6 benign lesions blood flow could be measured with the traditional color Doppler, but in 5 of 6 patients with the angio-color Doppler. This was also observed in ovarian tumors. Angio-color representation of renal transplants with normal function resulted in blood flow information reaching deep into the renal capsule, whereas in cases of renal transplants with impaired function a clearly reduced perfusion was visualized. These differences were not so evident with the conventional Doppler method. In lymph node diagnosis, too, marked differences between malignant and reactive lymph nodes could be visualized. In the diagnosis of arteriosclerotic plaques, blood flow in the residual lumen could also be detected more exactly with the angio-color technique. Color representation of liver tumors also showed a higher color signal density with ultrasound angiography. In summary, ultrasound angiography can provide additional information in the color representation of vessels with slow flow velocities. However, an obvious problem is the unability to quantify detected low blood flow. The new procedure will not replace but usefully complete the established sonographic techniques.

Arteriosclerosis↗
PubMed1995

[Does measurement of absolute velocity by Doppler examination of pregnant patients contribute additional valuable information?].

Ultrasonics is very important for the control of risk pregnancies. Routinely, Doppler-ratios are used to assess fetal danger. The aim of the presented study was to clarify whether measurement of absolute blood flow velocity is useful for the assessment of fetal development as well. For this purpose we examined the fetal aorta in 149 patients: 90 patients with fetal growth retarded fetuses and 59 patients with normally developed fetuses. Systolic and diastolic peak velocities and the resistance index (RI) were measured. The absolute velocities did not show any correlation to the fetal growth. Moreover, there was no correlation between systolic peak velocity and resistance index, independent of degree of pathology. The diastolic peak velocity however correlated with high significance to the RI thus being directly dependent.

Aorta, Abdominal↗
PubMed1995

[Ultrasound diagnosis of fetal lung maturity].

The immaturity of the fetal lung and the resulting respiratory distress syndrome are the main problems of obstetrics. Over a long period of time the only possibility to recognize the maturity of fetal lungs certainly was the determination of the L/S-ratio by amniocentesis. Two years ago first results were presented to determine fetal lung maturity by sonography. We examined 428 patients between 29 and 40 completed weeks of gestation. By comparing the characteristics of frequency of fetal lung echoes to those from the fetal liver as a reference organ it becomes possible to standardize fetal lung changes with gestation. In one ultrasound section we depicted lung and liver as well. According the A-mode we registered frequencies of both. The registered frequencies were entered digitally into a computer to evaluate the mean, maximal and minimal frequencies. Afterwards quotients of the frequencies of fetal lung and liver were calculated. For all weeks of gestation, mean values and standard deviations were made. It has been shown, that the liver is an adequate reference organ since the reflection pattern between the different weeks of gestation does not change, however significant changes have been seen in the fetal lungs. Q-mean, the quotient of fetal lung and liver reflection can be calculated. A quotient of Q-mean < 1.10 suggests lung maturity, while values > 1.10 speak for immaturity. Ultrasound examinations with 55 expectant women were compared with the lung conditions after delivery. 30 examinations were correlated with the results of the L/S-Ratio by amniocentesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniocentesis↗
PubMed1995

[Effectiveness of beta-hydroxyethylrutoside in patients with varicose veins in pregnancy].

Pregnancy is a critical risk for development of varicosis, therefore early detection and treatment are strongly recommended. In our study we examined 51 patients subdivided into three groups. One group underwent physical therapy (cold foot-baths in the morning an in the evening), the other group was administered beta-hydroxyethyl rutosides, and the patients of the third group had appeared only once for examination. Leg circumference and diameter of vein (by sonography) were measured, and the subjective criteria evaluated. In the group of patients who were additionally given drugs, a significant reduction of all parameters was found: leg circumference was reduced by 3% and diameters of veins were reduced by 15% on average, the reduction of the subjective criteria was by 34%. Provided the veins were prevented from further extension through progressive varicosis, apparent beneficial clinical effects can be achieved by administration of beta-hydroxyethyl rutosides.

Adult↗
PubMed1995

[Hysteroscopic endometrium ablation in "high-risk" situations and in hemorrhagic diathesis].

A hysteroscopic endometrial ablation (HEA) under maximal anesthesiologic surveillance was performed on 34 high-risk patients (group I: chronic anticoagulant therapy n = 26; group II: endogenous coagulopathy n = 8) with therapy resistant meno-metrorrhagia to avoid a hysterectomy (HE). Total amenorrhea, or a least hypomenorrhea respectively cyclic spotting could be attained primarily in 22 patients (group I: 19; group II: 3), after a repeat procedure in further 6 patients (4 in group I, 2 in group II). Subjective evaluation of surgical results (overall 22 patients primarily satisfied, 6 secondarily) also differed between the two subgroups (group I: p < 0.01 primarily satisfied; p < 0.05 secondarily satisfied vs. p < 0.05 and p < 0.01 in group II). A HE had to be performed on two patients due to extensive adenomyosis uteri interna (group II). The significantly better results in the anticoagulation group were probably due to the basic illness. Larger groups will, however, be necessary before any conclusions from this difference can be drawn. No surgical or anesthesiological complications occurred. There also were no major postoperative complications (1 endomyometritis, 2 cervical stenoses). Endometrial ablation was found to be a valuable treatment alternative for this specific group of patients with severe coagulopathy, thrombo-embolic or thrombotic disease.

Adult↗
PubMed1994

Diagnostic value of pelvic examination, ultrasound, and serum CA 125 in postmenopausal women with a pelvic mass. An international multicenter study.

BACKGROUND: In a prospective study, the differential diagnostic potential of pelvic examination, ultrasound, and serum CA 125 assay in postmenopausal patients presenting with a pelvic mass was assessed. METHODS: A total of 228 patients were evaluated preoperatively in an international, multicenter, prospective study using a standard protocol for pelvic examination, transvaginal (occasionally additional abdominal) ultrasound, and serum CA 125 determination with a cut-off level of 35 U/ml. RESULTS: Ninety-five malignant (41.7%) and 127 benign (55.7%) pelvic tumors were found in addition to 6 borderline ovarian tumors (2.6%) in the 228 patients. Seventy-two patients had ovarian carcinoma, 49 of whom were International Federation of Gynecology and Obstetrics Stage III or IV. Borderline tumors were excluded from the statistical calculations. The individual accuracy of pelvic examination, ultrasound, and serum CA 125 in discriminating between benign and malignant pelvic masses was approximately the same (76, 74, and 77%, respectively). Using logistic regression analysis, the power of pelvic examination appeared to be the most relevant factor (adjusted odds ratio, 9.2), followed by serum CA 125 (odds ratio, 5.6), and ultrasound (odds ratio, 4.9). Age appeared to be nonpredictive. No cancer was found in any patient in whom all three methods scored negative (n = 53; positive predictive value for malignancy = 0 and 95%; confidence interval, 0-7). CONCLUSIONS: The combined use of pelvic examination, ultrasound, and serum CA 125 leads to improved discrimination between malignant and benign pelvic masses, because malignancy can be excluded when all three examination methods are negative. A change to a more patient-tailored surgical approach could be considered in those cases.

Aged↗
PubMed1994

[Hysteroscopic endometrium ablation to avoid hysterectomy in "high risk" patients].

Hysteroscopic endometrial ablation under maximal anaesthesiological surveillance was performed in 34 high-risk patients to avoid hysterectomy. It was a collective of patients with heavy thrombo-embolic or thrombotic disease, either under permanent anticoagulation due to residual disease or multiple endoprosthetic treatment, or with endogenous coagulopathy. In all these women, hysterectomy was either a relative or an absolute contraindication. In 22 patients, treatment resulted in complete amenorrhoea or at least hypomenorrhoea (without menometrorrhagia) respectively cyclic spotting. In 6 further patients, amenorrhoea was achieved after a repeat procedure. Endometrial ablation was thus successful in 28 of 34 cases. In these patients, hysterectomy with the risk of major or even lethal complications, could thus be avoided. Hysterectomy, however, had to be performed in 2 women with extensive adenomyosis uteri interna. Within two respectively three years after endometrial ablation, two other patients died from causes unrelated to the surgical intervention (cardiac infarction, cerebral haemorrhage). Follow-up ranged from 1 to 5 years. Hysteroscopic endometrial ablation proved an effective therapeutic option in this selected group of patients. Other indications require further study.

Adult↗
PubMed1994

[Incontinence operation by "Retzius-scopy"? An endoscopic modification of the Marshall-Marchetti-Krantz operation].

The operative treatment of stress incontinence with the Marshall-Marchetti-Krantz procedure has proved effective. A new, endoscopic modification of this procedure is presented here, based on the principle of vesico-urethral suspension with fibrin glueing. Open abdominal surgery is replaced by retziusscopy and a minimal invasive endoscopic intervention in the Retzius' cavity.

Female↗
PubMed1994

[The positive "vocal fremitus" in malignant breast tumors in color MEM ultrasound imaging--an exciting artifact in confirming the diagnosis?].

In the experimental phase of application of a new Non-Doppler technology (MEM system, Acoustic Imaging, Phoenix; Dornier Medizintechnik) we observed, that in patients, who spoke during colour imaging of a breast tumour, artifacts appeared in or around the lesion: the colour artifacts were seen regularly inside the tumour in cases of malignancies, and exactly surrounding benign tumours. Postoperative histological findings served as an objective criterion of classification/differentiation. To examine this phenomenon, we performed a study in 71 patients. These women with a sonographically detectable tumour (37 malignant, 34 benign) were examined on the day before surgery. We observed, that if patients uttered the number "99" with a relatively low voice or alternatively hummed a deep sound, the artifacts could be regularly visualized. In 66/71 patients (93%) status evaluation by artifact generation due to vocal fremitus examination was correct. In 3 patients the tumour was erroneously described as malignant, histology showing a proliferative mastopathy. In 2 cases the tumour was classified as benign, whereas histology revealed a malignancy, in both patients a large ductal-invasive carcinoma (> 3 cm). This phenomena could, however, not be reproduced with other colour techniques. A possible explanation is: Thoracic vibrations during speech can be registered by the MEM technique. These vibrations are not perpetuated into the benign lesion characterised by a displacing growth, due to which the vibrations are "barred off" at the borders of the tumour. Infiltrating growth typical of a malignancy causes transmission of these vibrations into the center of the tumour.(ABSTRACT TRUNCATED AT 250 WORDS)

Artifacts↗
PubMed1994

[Development of Doppler parameters in fetal and maternal blood vessels 10 days before to 10 days after the calculated due date].

Doppler sonography can help to assess a foetal risk situation prospectively. This procedure is therefore well suited for the screening of risk pregnancies in the 3rd trimenon. The role of Doppler ultrasound at delivery is still controversial, since, on the one hand, no data on the behaviour of Doppler parameters directly at the onset of delivery are available, and on the other hand the obstetric consequences from pathological findings are not clear. For this reason, we observed 45 normal pregnancies from the 10th day prior to the date of confinement till the 10th day post partum. In 20 patients we registered Doppler parameters from 4 days before until the onset of true labour. In all these cases, a reduction of the end-diastolic blood flow in the foetal aorta was found, which became evident by the increase of the resistance index to pathological values. Concomitant decrease of the resistance index in the foetal carotid artery was typical for a circulatory system. Since foetal outcome was normal in all newborn, this change in Doppler parameters directly at the beginning of labour must be considered as physiological. The findings suggest a physiological placental insufficiency. Since however, parameters in the uterine vessels did not show any changes, the insufficiency has its probable origin in the placenta. From these findings, one might speculate, that the supply deficiency is the labour inducing factor. No clinical consequence can thus result from pathological Doppler data found in patients directly prior and after delivery. Cardiotocographic screening is necessary.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Diagnosis of the breast tumor entity with "vocal fremitus" in ultrasound diagnosis].

In the published study a totally new method for the diagnosis of malign and benign tumors of the female breast is presented. During sonographic examinations with the maximum entropy method we found out, purely by chance, that artifacts produced by vibrations of the thorax can be used to differentiate malignant from benign lesions. These artifacts in form of small colour pixels can be provoked by the vocal fremitus of the internal medicine or by humming a deep sound. In case of malignancy, the colour artifacts are visible inside of the tumor, in benign lesions, however, only in the surrounding tissue. On the preoperative day, 95 patients were examined with the method described above. In 91% of the cases the diagnosis of the dignity corresponded with the histological results. Seven times a benign lesion was classified as a malignant tumor and twice malignancy was not correctly diagnosed. Our explanation of these phenomena is the following: Benign lesions of the female breast show a displacing growth and a definable boundary. Thus the vibrations are damped and not conducted into the tumor. In contrast, malignant lesions grow invasively into the surrounding tissue. Consequently, the vibrations can be conducted into the center of the tumor by this dissemination.

Adenocarcinoma↗