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Biomedical subjects

I Thaler

Publications and source records attributed to I Thaler.

At least 37 records · Page 2Linked to original sources
PubMed1991

Classification of tubal gestations by transvaginal sonography.

Transvaginal sonographic images of tubal pregnancies were correlated with the surgical findings in 191 patients having this condition. The sonographic appearance of the ectopic gestations was classified by the absence or presence of structures such as a 'tubal ring' containing the yolk sac, embryonic structures, heart activity, a sonolucent or irregularly echogenic gestational sac, dilated Fallopian tube with amorphous content, fluid in the pelvis and an empty uterus. The following classifications were made: Type Ia (n = 43) A well-defined 'tubal ring' and a beating heart with or without discrete embryonic or extra-embryonic structures. Type Ib (n = 48) A 'tubal ring' containing embryonic and/or extra-embryonic structures without heart beats. Type II (n = 64) An ill-defined or thin tubal wall containing sonolucent or an irregularly echogenic core but not embryonic or extra-embryonic structures. Type III (n = 28) Free pelvic fluid and an empty uterus in patients with positive serum beta-hCG levels. The outline of the tube cannot be visualized. Surgery revealed unruptured tubal pregnancies in 90 patients of the combined groups of Types Ia and Ib. In one additional patient, a tubal rupture was found. In the Type II patients, 26 tubal pregnancies with blood clots in the tube but no evidence of bleeding into the pelvis, and 38 tubal ruptures or abortions were diagnosed. All Type III patients had ruptured tubal pregnancies or bleeding tubal abortions. In eight patients (4.2%), the only sonographic finding was an empty uterus, and these cases were erroneously diagnosed as not having an ectopic pregnancy (false negatives). There were two false-positive cases in which a tubal ring was detected, and this was related to an hemorrhagic corpus luteum. When used for diagnosing tubal pregnancy, the transvaginal scanning technique (together with beta-hCG in Type III cases) carries a sensitivity of 95.8% and specificity of 99.9%. It is an invaluable tool in the diagnostic work-up and management of patients with suspected ectopic gestation.

Journal Article↗
PubMed1991

The physical and psychomotor development of children conceived by IVF and exposed to high-frequency vaginal ultrasonography (6.5 MHz) in the first trimester of pregnancy.

We examined the physical and psychomotor development of 33 infants conceived by in vitro fertilization (IVF) who were exposed to high-frequency transvaginal ultrasonography (HFTVS) (6.5 MHz) in the first trimester of pregnancy. The study group was composed of 21 singletons and six sets of twins. Thirty-three non-IVF controls were matched for birth weight, gestational age, sex, birth order, order in multiple delivery, mode of delivery, age at examination and parental age and education. Forty-five IVF infants who were not exposed to HFTVS and their matched controls also served as comparison groups. The Bayley scales were used to assess the psychosocial development of the infants studied. Increases in preterm delivery, low birth weight and Cesarean section rates were within the acceptable range for IVF babies. Mean birth weight, gestational age and birth weight percentiles of exposed IVF infants were lower than the expected mean for a normal population, but did not differ from that of non-exposed IVF infants. Mean percentiles of weight and length at examination were also low but not different from those of non-exposed IVF and matched control groups. However, percentiles of head circumference were normal at birth and at examination both in study and control groups. Overall, Bayley scores of exposed IVF infants were within the normal range and did not differ significantly from those of their matched controls and non-exposed peers. These scores were significantly correlated to birth weight, percentiles of birth weight and head circumference at birth and at examination, and to the mother's education. Twins had lower physical and mental indices than singletons, but did not differ from their controls.

Journal Article↗
PubMed1991

Effect of calcium channel blocker nifedipine on uterine artery flow velocity waveforms.

Calcium channel blockers have been used successfully in the treatment of pregnancy hypertension and premature labor. Only limited information related to their effect on uterine blood flow during pregnancy is available. In this study we measured the ratio between peak systolic to end-diastolic flow velocity (S/D ratio) in the ascending branch of the uterine artery in nine pregnant patients prior to and following a 10-mg dose of sublingual nifedipine. Another group of seven matched patients who received a placebo served as a control group. All studies were performed between 17 and 22 weeks gestation. The S/D ratio decreased shortly after sublingual nifedipine, but the change was not significant. It increased gradually afterward so that by 60 minutes it returned to the control value. The mean systolic blood pressure decreased by 8.6% to its lowest value after 25 minutes (P less than 0.01). The mean diastolic blood pressure decreased by 15.7% to its lowest value after 35 minutes (P less than 0.002). Maternal heart rate did not change significantly. No significant changes were observed in any of the measured variables in the placebo group. In conclusion, nifedipine does not induce significant changes in uterine arterial resistance in midtrimester and may be considered during pregnancy, providing that large fluctuations in maternal blood pressure are avoided.

Arteries↗
PubMed1991

Anticardiolipin antibodies in patients with recurrent pregnancy wastage: treatment and uterine blood flow.

The interest in autoimmune pregnancy loss has increased recently with the discovery of the association between the presence of antibodies to phospholipids and cardiolipin and habitual abortion. To evaluate the prevalence of anticardiolipin antibodies in patients with recurrent fetal loss and the effect of low-dose aspirin and corticosteroid treatment, we examined 67 women for anticardiolipin antibodies with an enzyme-linked immunosorbent assay. Increased levels of anticardiolipin antibodies were found in 34 of these women (50.7%) and in none of 12 normal pregnant controls. Seventeen of these 34 patients conceived and were treated with aspirin, 100 mg/day, and fluocortolone, 10 mg/day. Twelve gravidas reached term, all delivering live infants with good Apgar scores and normal birth weights. Three others delivered prematurely, two of them because of premature rupture of membranes and the other because of severe fetal growth retardation. This latter woman delivered at 31 weeks, and the 1000-g infant died neonatally. The neonatal survival rate was 82% in the treated patients, versus 18% in the same group of subjects in their previous, untreated gestations. The umbilical artery resistance index of the treated subjects was not different from that of anticardiolipin-negative hypertensive women who did not receive aspirin and corticosteroid therapy. However, the uterine artery resistance index was significantly lower in the hypertensive treated group than in the untreated group. Whether this difference reflected a beneficial effect of low-dose aspirin and corticosteroid therapy on pregnancy outcome and survival rate remains to be evaluated.

Abortion, Habitual↗
PubMed1990

Transvaginal imaging: applied physical principles and terms.

In this article the properties of ultrasound in tissues and the factors governing image quality are discussed. Particular emphasis is placed on the vaginal probe. The virtues of transvaginal scanning both in gynecology and obstetrics are well described in subsequent articles in this symposium. Only by understanding the properties of ultrasound can the capabilities and limitations of this technique be appreciated. A comprehensive knowledge of the basic physical principles is mandatory for the clinician as well the investigator to attain the highest quality results. The technical aspects of operating ultrasound instruments, e.g., machine controls, electronic image formation, scan converters and techniques for preprocessing and postprocessing, are not discussed.

Female↗
PubMed1990

Transvaginal sonographic technique: targeted organ scanning without resorting to "planes".

The orientation of the sonographer performing a transvaginal scan is currently based on a concept of anatomical planes, which is customary in transabdominal sonography. We challenge this concept and propose a different approach altogether based on focusing on target organs rather than anatomic planes. The problem of orientation in transvaginal sonography stems from the following: (1) There is a very short distance between the relatively high-frequency transvaginal transducer-probe and the scanned area; a close-up image is generated encompassing a single organ or only part of it. (2) The scanning angle is initially perpendicular to that of abdominal sonography. (3) Transvaginal sonography is an endocavitary dynamic scanning technique. According to the experience in our department (30,000 examinations during the past 4 years) and in two other medical centers, best results from the transvaginal ultrasonographic examination are achieved when the operator searches for every specific organ as the main target, without resorting to pelvic "planes." The guidelines for targeted organ scanning and the associated change in orientation are reported together with the limitations. Targeted organ scanning without resorting to "planes" helps the operator to resolve the problem of orientation during the transvaginal ultrasonographic examination, and to simplify the procedure to a great extent.

Fallopian Tubes↗
PubMed1990

Transvaginal ultrasonography in the diagnosis and treatment of infertility.

The use of transvaginal sonography (TVS) in the management of infertility is gaining increasing popularity. The improved resolution and better tissue textural differentiation afforded by TVS makes this technique useful in monitoring ovarian follicular growth, ovulation, and corpus luteum formation, and in evaluating the normal anatomy of the uterus and the cervix and their cyclic response to ovarian steroids. Adnexal and cul-de-sac abnormalities related to infertility can also be identified. TVS-guided procedures can be accurately and safely performed; transvaginal follicular aspiration, gamete or embryo transfer to the Fallopian tube, and fetal reduction are just a few of the procedures recently introduced to reproductive medicine.

Cervix Uteri↗
PubMed1990

Criteria for transvaginal sonographic diagnosis of ectopic pregnancy.

Transvaginal ultrasonography was performed in 1150 patients suspected of having an ectopic gestation. The criteria for transvaginal sonographic diagnosis of ectopic pregnancy were established by targeted scanning of the pelvic organs and spaces. Sonographic assessment of tubal pregnancy and its differential diagnosis were based on six criteria: (1) the presence or absence of gestational structures within the fallopian tube, (2) the presence or absence of amorphous material in a dilated fallopian tube, (3) the presence or absence of indirect signs of ectopic pregnancy within the pelvis, (4) the echogenicity of a suspected finding relative to the ovary, (5) the presence or absence of flow (of lacunar origin) within the suspected sonographic finding, and (6) the relationship of a suspected sonographic sign to an intentionally displaced ovary. The latter 3 criteria help differentiate between tubal gestation and a corpus luteum. We believe these diagnostic criteria should be applied when performing transvaginal sonographic scanning of patients suspected of having an ectopic gestation.

Corpus Luteum↗
PubMed1990

First trimester selective reduction in multiple pregnancy guided by transvaginal sonography.

Transvaginal ultrasonography-guided fetal reduction was performed in 11 patients presenting with multiple pregnancies. Embryonic aspiration was carried out in 7 women at 7 to 8 weeks and in 4 patients fetal intrathoracic injection was performed at 9 to 11 weeks, menstrual age. Seven patients delivered healthy babies at greater than 35 weeks, 3 have delivered prematurely 15 to 17 weeks after the procedure with subsequent neonatal death of all sets of twins. We believe that our method overcomes the technical difficulties related to the transabdominal or transcervical approach and should be the method of choice for early selective abortion.

Abortion, Induced↗
PubMed1990

The uterus: a new look with transvaginal sonography.

Targeted scanning of the uterus and its adjacent structures is made possible by high-resolution transvaginal sonography. A systematic approach is applied so that the normal anatomy and abnormal processes in the various uterine components can be visualized. By adopting this method we detected various pathologies in the cervix, endometrium, myometrium, and in the uterine vessels and ligaments. Cervical pathology included inflammatory processes, cysts, malignant lesions, and incompetence during pregnancy. By scanning the endometrium, a reflection of the hormonal status of the patient under both normal (e.g., the menstrual cycle) and abnormal conditions may be obtained. More sinister lesions, such as endometrial hyperplasia and carcinoma, can be suspected based on the sonographic appearance of the endometrium. In hydatiform mole, a typical sonographic picture directs the sonographer to the diagnosis. Uterine fibroids are the most common lesion of the corpus uteri, and are readily detected by transvaginal sonography, including any degenerative changes that may complicate this condition. Changes in uterine size, particularly when accompanied by profuse intracavitary fluid, should raise the suspicion of a malignant process. Intracavitary fluid may also be associated with inflammatory lesions (e.g., tuberculosis). Congenital uterine anomalies may be diagnosed and defined by this method. Uterine ligaments are best visualized in the presence of fluid in the pelvis. Intraligamentary masses can be also be detected and defined. Finally, the main vessels supplying the uterus can be visualized, both in pregnant and nonpregnant patients. Using a transvaginal image-directed Doppler system, flow velocity profiles can be obtained from these vessels and form the basis for defining abnormalities in uterine perfusion.

Adolescent↗
PubMed1990

Classification of ovarian lesions by high-frequency transvaginal sonography.

Two hundred patients suspected of having ovarian pathology were scanned with a 6.5-MHz transvaginal probe. Normal anatomical structures and abnormal findings were recorded and classified according to their shape, size, location, and sonographic characteristics. The sonographic images were correlated with the surgical findings, whenever available. A sonographic classification of ovarian lesions was compiled according to the presence or absence of the following sonographic components: septae, papillae, loculations, daughter cysts, solid mass, or fluid, and their relationship to malignancy.

Female↗
PubMed1990

Hemodynamic evaluation of the female pelvic vessels using a high-frequency transvaginal image-directed Doppler system.

Perfusion characteristics of the female pelvic vessels were studied by a high-frequency transvaginal image-directed Doppler system. A 5-MHz Doppler transducer was coupled to a 6.5-MHz probe especially designed for intravaginal use. Distinct patterns of flow velocity waveforms were obtained from the ascending branch of the uterine artery, before and during pregnancy. A gradual increase in diastolic flow throughout gestation was observed, consistent with a decrease in vessel resistance. Flow velocity profiles in the ovarian artery were sampled from the infundibulo-pelvic ligament. Only limited diastolic flow could be detected in either ovary during the follicular phase of the cycle. In the luteal phase there was a marked increase in this flow but only in the ovary containing the corpus luteum. In early pregnancy the high diastolic flow was maintained or even increased, consistent with a low arterial resistance. High image resolution and a higher frequency Doppler transducer increase the usefulness of this technique in the hemodynamic evaluation of the female pelvic vessels.

Blood Flow Velocity↗
PubMed1990

Changes in uterine blood flow during human pregnancy.

A transvaginal duplex Doppler ultrasonography system was used to measure blood flow characteristics in the ascending uterine artery before and during pregnancy. The system uses a 5 MHz Doppler transducer coupled to a 6.5 MHz imaging probe. There was a steady increase in volume flow rate in the left ascending uterine artery from a mean of 94.5 ml/min before pregnancy to a mean of 342 ml/min in late gestation (reflecting a 3.5-fold increase). With the assumption of equal flow on both uterine arteries, the fraction of the cardiac output that is distributed to these vessels was calculated to be 3.5% in early pregnancy and to reach 12% near term. The mean diameter of this vessel in the nonpregnant state was 1.6 mm, increasing to 3.7 mm toward term. The resistance to flow, expressed as the peak systolic to end-diastolic flow velocity ratio, declined from a mean of 5.3 in the nonpregnant state to a mean of 2.3 near term. These changes reflect the perpetual growth and development of the uteroplacental circulation, which provides the metabolic demands of the growing fetus throughout gestation.

Arteries↗
PubMed1990

Duplex sonography in the diagnosis of portal vein thrombosis.

Portal vein thrombosis was readily diagnosed by pulsed duplex Doppler sonography in five patients. The cases represent different stages in the development of the thrombotic event, from partial or complete occlusion by an echogenic intraluminal thrombus to cavernous transformation of the portal vein. The unique ability of duplex scanning to demonstrate abnormal vascular structures and flow pattern is emphasised. This method should be the technique of choice in the diagnosis of portal vein thrombosis.

Aged↗