Biomedical subjects

R Tepper

Publications and source records attributed to R Tepper.

At least 55 records · Page 3Linked to original sources

PubMed1997

Decay constant of Doppler flow waveform as a possible indicator of ovarian malignancy.

The objectives of this study were to analyze the decay constant (tau) of the Doppler flow waveform in ovarian tumors; to determine if differences in this constant can discriminate between malignant and benign ovarian tumors; and to compare the decay constant to the known resistive index (RI), in order to determine its potential prognostic application. Patients with ovarian masses (46) were evaluated in a retrospective study; 13 had malignant tumors, 7 showed tumors with low malignant potential (LMP), 11 had benign masses, 4 had secondary ovarian metastases and 11 had functional ovarian masses. Doppler flow waves measured in the ovary before operation were analyzed from archival videotapes. The RI was calculated preoperatively, and the decay constant of the flow waveform was analyzed retrospectively. We approximated the decaying portion of the flow waveform from the systolic peak to the diastolic level to an exponential curve. Then, the decay constant associated with the flow signal was compared for different types of ovarian pathology. Ovaries with malignancies showed significantly higher mean values for the decay constant (89.7; 95% confidence interval 60.0-119.3) than those with benign tumors (41.8; 25.7-57.9) (p < 0.007), where tau is provided in pixels (in this study each pixel equals approximately 11.4 ms). The mean RI value for malignant tumors was 0.44 +/- 0.12 whereas, in benign tumors, it was 0.622 +/- 0.11. For the benign tumors, both tau and RI did not differ significantly from the measured indices in LMP tumors, metastases and functional ovarian findings. In addition, when the cutoff value of tau was set at 48, 92.3% of all malignancies were identifiable using only tau. This preliminary study indicates that the decay constant of the Doppler flow waveform is able to discriminate between malignant and benign masses and may, thus, provide substantial assistance as an additional parameter in the diagnosis of malignant ovarian tumors in postmenopausal patients.

Adult↗

PubMed1997

The contribution of pelvic ultrasonography to the diagnostic process in pediatric and adolescent gynecology.

We suggest that using the sonographic examination as an integral part of the work-up may save the physician and the patient from an unpleasant and uninformative examination, and avid EUA or unnecessary surgery. The type or sonographic examination should be determined by what is known, the equipment available, and the age and past history of the patient. In our institution the transabdominal approach is the choice for any nonsexually active female and the transvaginal approach is the procedure of choice for those females who are emotionally mature and sexually active. This review is addressed to the clinicians taking care of the pediatric and adolescent population. We wish to stress the importance of the sonographic evaluation as an immediate tool for the evaluation of suspected pelvic pathology, gender identity, and sexual-development disorders. We find it convenient and accurate, and feel that in children and young women with such pelvic complaints, it should be considered an important step in the diagnostic process.

Adolescent↗

PubMed1997

High frequency of adenomyosis in postmenopausal breast cancer patients treated with tamoxifen.

Pathologic evaluation for adenomyosis in uterine specimens as well as demographic characteristics, health habits and risk factors for endometrial cancer were compared in 28 postmenopausal breast cancer patients with tamoxifen (TAM) treatment and in 11 similar patients without TAM treatment in order to determine the association between postmenopausal TAM exposure and the frequency of adenomyosis. The same comparison was also made between TAM-treated patients with adenomyosis and TAM-treated patients without adenomyosis. Adenomyosis was histologically diagnosed in 53.6% TAM-treated patients and in 18.2% non-TAM patients. Overall, there were no significant statistical differences in all parameters tested between the 2 groups, as well as between the TAM-treated patients with adenomyosis and the TAM-treated patients without adenomyosis. It can be concluded that adenomyosis was significantly more common among postmenopausal breast cancer patients who were treated with TAM as compared to similar patients without TAM treatment (p = 0.0186). This significant high rate of adenomyosis may be attributed to the continuous and unopposed exposure to TAM. It is, however, impossible to predict which postmenopausal breast cancer patient will develop adenomyosis after treatment with TAM.

Aged↗

PubMed1997

Different coexisting endometrial histological features in asymptomatic postmenopausal breast cancer patients treated with tamoxifen.

In an attempt to assess the hypothesis that different endometrial sites may respond differently to tamoxifen exposure in postmenopausal women, hysteroscopic selected endometrial histology was investigated in 175 postmenopausal breast cancer patients who received continuous treatment with tamoxifen, and in 27 similar patients not treated with tamoxifen who served as controls. In the tamoxifen-treated patients 14 (8.0%) developed endometrial polyps. Of 14 patients, 8 (57.2%) each displayed atrophic endometrium in the same histologic specimen, 5 (35.7%) each had coexisting simple hyperplasia, and 1 (7.1%) other had complex hyperplasia. Another 21 (12.0%) developed simple or complex hyperplasia. The endometrial hyperplasia coexisted with atrophic endometrium in all these patients. All these lesions were selectively identified by hysteroscopic examination prior to the endometrial biopsy. In the control group 3 (11.0%) had simple hyperplasia and 2 (7.4%) had endometrial polyps. The above results support the hypothesis that the endometrium of postmenopausal breast cancer patients on tamoxifen treatment may possess different responses to tamoxifen exposure.

Aged↗

PubMed1997

The tradeoffs of successful simulation.

This presentation will discuss the decision process we followed to develop an ultrasound simulator. The development of an advanced technology medical device always requires tradeoffs and compromises between what is desired, and what can be realistically achieved. The medical applications of computer based education are increasingly important to the process of medical education. Product developers will be required to address these concerns. Some tradeoffs result from technical, scientific, and engineering factors; while others are the result of marketing, financial, or competitive constraints. All of these factors will influence the design and production of simulation tools. A manager, scientist, or engineer who is involved in development of this kind of innovative product may be helped by considering the impact of some of these decisions earlier in the process. Forewarned is fore-armed. The most basic design issue we faced was the conflict between the requirements we envisioned for the ultrasound simulator, and the limitations of realistic simulation. Our goal was to achieve a product which would be affordable to the academic institutions who would be using it. Simulation will be defined and presented with examples from our experience.

Biomedical Engineering↗

PubMed1997

Doppler flow characteristics of dermoid cysts: unique appearance of struma ovarii.

The purpose of our study was to evaluate the Doppler flow characteristics of ovarian dermoid cysts. In 70 women (mean age, 38.7 +/- 14.6 years), 78 ovarian lesions with mean diameter of 48.9 +/- 28.4 mm and preoperative sonographic diagnosis of dermoid cyst of the ovary were evaluated prospectively by Doppler flow sonography; these cysts were eventually removed surgically. The findings were compared to the postoperative histologic results. In 74 lesions (eight cases were bilateral), when blood flow patterns were detected (detection rate of 24.3%) they were obtained only from the ovarian tissue surrounding the dermoid cavity, with a mean resistive index of 0.6 +/- 0.1 (range, 0.4 to 0.76). In four cases, which were proved postoperatively to be struma ovarii, blood flow was detected not only from the cyst capsule but also from the centrally positioned solid area (dermoid tissue), with a mean RI of 0.565 +/- 0.08 (range, 0.509 to 0.667). Dermoid cysts of the ovary are devoid of blood flow, with flow detection rate being only 24.3% from the cyst capsule. When apparently vascularized solid tissue is detected in the central part of a sonographically suspected benign cystic teratoma, struma ovary is highly suspected.

Adolescent↗

PubMed1997

Elevated hCG as an isolated finding during the second trimester biochemical screen: genetic, ultrasonic, and perinatal significance.

This study was undertaken in an attempt to determine the significance of elevated maternal serum human chorionic gonadotropin (MShCG), in the presence of an otherwise normal screen with respect to fetal malformations, chromosomal aberrations, and pregnancy outcome. Targeted ultrasound findings and perinatal outcome of 298 women in whom serum hCG was > or = 2.5 MOM and who were screen-negative for Down syndrome (the study group) were compared with a control group of 229 women in whom serum hCG as well as the other parameters were within the normal range. Genetic amniocentesis was performed in 125 women from the study group. Ultrasonically detected malformations were significantly more frequent among the study group (12 vs. 1, P = 0.01). Pregnancy complications were similar in the two groups, with the exception of pre-eclampsia-toxaemia, which was significantly more frequent in the study group (5 vs. 0, P = 0.02). There was one case of an abnormal karyotype (47,XXY). Although genetic amniocentesis does not appear warranted, isolated elevated MShCG levels during the second trimester screening was associated with an increased risk of fetal anomalies detected by ultrasound and of toxaemia of pregnancy.

Adult↗

PubMed1996

Transvaginal color Doppler ultrasound in the assessment of invasive cervical carcinoma.

OBJECTIVE: To assess the validity of transvaginal color Doppler flow in the prediction of malignancy in the uterine cervix. STUDY DESIGN: Sixteen women with cervical pathology (14 with invasive carcinoma and 2 with cervical intraepithelial neoplasia III) were examined using transvaginal sonography as well as transvaginal color Doppler with measurements of the resistance index of tumor blood flow. Twenty-four women with histologically proven normal cervices served as a control group. RESULTS: Resistance index (RI) was significantly lower in the study group [0.493; 0.475-0.511 (mean + 95% CI)] than in control group [0.643; 0.627-0.659] (P < 0.0001) (t'). There was no statistically significant difference between the carcinoma group and the CIN III cases (P = 0.067) (t'). Only two cases with cervical carcinoma showed dense vascularity with color Doppler. A RI cutoff less than or equal to 0.573 showed a sensitivity of 81% with a specificity of 93%, a positive predictive value of 93%, and a negative predictive value of 81%. CONCLUSION: Color Doppler flow evaluation of RI in cervix vessels may aid in the early diagnosis and management of cervical carcinoma and in differentiating benign from malignant tumors. The validity of this technique as a screening program for diagnosis is limited.

Adolescent↗

PubMed1996

Ovarian tumors in postmenopausal breast cancer patients treated with tamoxifen.

From September 1, 1989, to November 30, 1994, 175 menopausal breast cancer patients treated with tamoxifen were followed at the authors' institutions. During this period. 16 (9.1%) underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy, for various indications. Of these, 10 (62.5%) had either uni- or bilateral ovarian tumors. The analysis of surgical findings showed an incidence of 5.7% (10/175) ovarian tumors among all the patients. In 2 (20%), the ovarian masses displayed enlargement over a relatively short period while on treatment. In 5 (50%) patients, the findings were bilateral. All tumors were detectable by ultrasonography, except four serous cystadenomas found in 3 women. The mean duration of tamoxifen treatment was 36.6 +/- 24.9 (range 9-86) months. The rate of 5.7% for ovarian tumors, in this selected group of patients, is four to five times higher than that reported for similar pathologic conditions detected by general screening with ultrasonographic scans among nonselected, asymptomatic, and untreated postmenopausal women. Two possibilities should be considered in the development of ovarian tumors coinciding with tamoxifen treatment; (1) women with breast malignancy are prone to develop benign or malignant ovarian tumors in relation to genetic factors, regardless of tamoxifen treatment; and (2) tamoxifen may stimulate enlargement of such tumors and may even cause them.

Aged↗

PubMed1996

Genetic diagnosis from formalin-fixed fetal tissue using FISH: a new tool for genetic counseling in subsequent pregnancies.

We evaluated the feasibility of retrospective genetic testing for numerical chromosomal aberrations by applying the FISH technique to formalin-fixed fetal tissue. Fetal tissue from 10 old cases with known aneuploidy and from 13 cases with known fetal malformations, were tested with specific DNA probes for pericentromeric repeat regions of chromosomes 13/21, 18, X and Y. FISH diagnosis concurred with karyotype in all nine cases with sufficient cells. Numerical aberration was diagnosed in six out of 13 cases with fetal malformations.

Aneuploidy↗

PubMed1996

Diagnostic value of transvaginal color Doppler flow in ovarian torsion.

OBJECTIVE: To evaluate the role of Doppler flow in the diagnostic process of ovarian torsion. METHODS: Twenty-two patients who displayed the clinical symptoms of abdominal pain concomitant with an ovarian mass and were scheduled for explorative laparoscopy were enrolled in the study. The cohort was divided into 3 groups: (A) 8 patients with clinical and sonographic evidence of torsion; (B) 8 patients with abdominal pain and sonographic diagnosis of hemorrhagic cyst; and (C) 6 patients with a simple cystic mass who had undergone explorative surgery due to abdominal pain. RESULTS: After Doppler flow imaging, Group A displayed no blood flow within the mass, and surgery confirmed the diagnosis of ovarian torsion. Seven of the 8 group B patients showed ovarian vascular flow (RI = 0.472 +/- 0.067). Only 2 of the 6 Group C patients displayed vascular flow (RI = 0.680 +/- 0.129) within an untwisted cyst, confirmed by laparoscopy. CONCLUSIONS: The combination of Doppler flow imaging with the morphologic assessment improves the diagnostic accuracy of ovarian torsion.

Abdominal Pain↗

PubMed1996

The distribution of the local entropy in ultrasound images.

In this article, a model for the amplitude statistics of the backscattered ultrasonic signal is presented. We propose to view a tissue as being composed of a large number of small units, each having slightly different characteristics. This variability within the tissue is expressed by fluctuations in the parameters of the local probability distribution function (PDF). Based on analogous expressions derived for radio propagation and optical scintillations, the local PDF is modulated by a lognormal distribution of the local standard deviation. Integrating the local contributions yields the amplitude PDF for the entire tissue. We show that the local entropy is a normal variable, since for four different local PDFs it is linearly related to the logarithm of the local standard deviation. When the local entropy histogram exhibits distinct and multiple peaks, the local entropy distribution can be used for region segmentation. This fact is demonstrated for ultrasonic images of ovarian cysts.

Entropy↗

PubMed1996

The effect of medroxyprogesterone acetate and clomiphene citrate on platelet function in menopausal women.

OBJECTIVE: We sought to determine if antiestrogens such as clomiphene citrate (CC) and medroxyprogesterone acetate (MPA) affect platelet activity in postmenopausal patients before and after treatment with estrogens. METHODS: Using an incubation study, we analyzed the effects of CC and MPA on adenosine diphosphate and adrenaline-induced platelet aggregation and on the release of adenosine triphosphate in postmenopausal patients, using a platelet study, we analyzed the effect of these drugs on platelet function. RESULTS: Platelets were inhibited by MPA and CC in the incubation study but not significantly affected in the platelet study. Platelets previously incubated with estrogen were less inhibited by CC than by MPA. DISCUSSION: Thus, platelet study to determine the optimal combination therapy for menopausal patients has indicated that CC has a non-significantly less beneficial in vitro effect on platelet function than MPA.

Adenosine Diphosphate↗

PubMed1996

Antenatal ultrasonographic findings differentiating complete from partial agenesis of the corpus callosum.

Four cases of complete (three) and partial (one) agenesis were evaluated ultrasonographically. The frontal lobe/biparietal diameter ratio were evaluated in 113 normal fetuses and compared with those ratios in fetuses with corpus callosum agenesis. In the presence of the classic ultrasonographic features of agenesis of the corpus callosum, frontal lobe shortening, along with absence of the cavum septi pellucidi, might contribute to the diagnosis of complete agenesis of the corpus callosum and distinguish it from partial agenesis.

Adult↗

PubMed1996

A two-dimensional extension of minimum cross entropy thresholding for the segmentation of ultrasound images.

Segmentation is often an important step in medical image analysis. The local entropy is a possible variable for segmenting ultrasound images containing fluid surrounded by a soft tissue. A commonly used tool for image segmentation is thresholding. Recently, a new thresholding technique, known as "minimum cross entropy thresholding" (MCE), has been proposed. We present a multivariate extension of MCE in which the segmented variable (gray level) is replaced by a weighted combination of several image parameters. We propose to use a bivariate extension of MCE, which uses a linear combination of the gray level and the local entropy. The results obtained are demonstrated for ultrasound images of ovarian cysts.

Algorithms↗

PubMed1996

Common endometrial decidual reaction in postmenopausal breast cancer patients treated with tamoxifen and progestogens.

In order to assess endometrial reaction to the combined treatment of tamoxifen and progestogens in asymptomatic postmenopausal breast cancer patients, we evaluated all such patients by vaginal ultrasonography and by histological examination of endometrial samplings. All patients were initially treated with tamoxifen, and progestogens were then added when metastases became evident. Of 12 patients included in the study, eight (66.66%) showed evidence of strong endometrial stromal decidualization, while three (25%) had decidual reactions in endometrial polyps. Overall, 11 (91.66%) of the patients had decidual reactions, and all were treated with progestogens for > or = 3 consecutive months. One patient, treated with progestogens for 1 months, had an inactive endometrium. All but three had thickened endometria (> 10 mm) on ultrasonographic evaluation. These data show that postmenopausal breast cancer patients who received progestogens for < or = 3 months, and who concomitantly took tamoxifen, had a uniform decidual reaction in all uteri.

Adult↗

PubMed1996

Time-dependent effect of tamoxifen therapy on endometrial pathology in asymptomatic postmenopausal breast cancer patients.

Various endometrial lesions were more frequent among asymptomatic postmenopausal breast cancer patients who were treated with tamoxifen for > 48 consecutive months (30.8%) when compared with similar patients who were treated for 6-24 months or for 25-48 months (20.8% and 12.5%, respectively). However, this difference was not statistically significant. There were also no significant differences in the frequency of the various endometrial lesions between these three groups, although endometrial polyps were more frequently found among those treated for > 48 months. Overall, 20.7% of the 164 tamoxifen-treated patients in the study had an endometrial pathology. It can be concluded that there is a slight tendency among those postmenopausal patients who have been treated for > 48 consecutive months to have a higher frequency of endometrial lesions.

Analysis of Variance↗

PubMed1996

Differential diagnosis and management of very low second trimester maternal serum unconjugated estriol levels, with special emphasis on the diagnosis of X-linked ichthyosis.

Incorporation of maternal serum unconjugated estriol into the calculation of risk may increase the yield of serum screening performed during pregnancy for detection of fetal chromosomal and structural anomalies. The differential diagnosis of very low and undetectable levels of unconjugated estriol in maternal serum is discussed, with special emphasis on the prenatal diagnosis of X-linked ichthyosis. The prenatal detection of these findings dictates skilled genetic counseling, targeted sonographic evaluation and examination of fetal karyotype and fetal cDNA for Xp 22.32 with amniotic fluid levels of cortisol, STS, and ASC.

Adult↗