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Biomedical subjects

G Kossoff

Publications and source records attributed to G Kossoff.

At least 37 records · Page 2Linked to original sources
PubMed1988

Transvaginal pulsed Doppler ultrasound assessment of blood flow to the corpus luteum in IVF patients following embryo transfer.

The waveforms of vessels supplying the ovaries of women on an in-vitro fertilization (IVF) programme were studied using transvaginal B-mode and Doppler ultrasound. There were 125 scans recorded in 65 women at weekly intervals from 3 days after embryo transfer or 5 days after gamete intrafallopian transfer (GIFT) until confirmation of pregnancy or onset of menses. At each examination the signals obtained from vessels supplying the ovaries were recorded and quantified using a resistance index (RI). Fifteen patients became pregnant of whom one has subsequently miscarried. There was a highly significant difference in the RI values between patients who became pregnant and those who did not; no patient who became pregnant had a RI greater than 0.5. Oestrogen to progesterone ratios were calculated in the subgroup of non-pregnant patients and there was no correlation between these values and the RI values. This new technique enables prediction of IVF treatment failure earlier than has been reported previously and may reflect the inadequacy of the corpus luteum.

Corpus Luteum↗
PubMed1987

Sister chromatid exchange frequency in human lymphocytes after long duration exposure to pulsed ultrasound.

The aim of this study is to determine whether sister chromatid exchange (SCE) frequency increases in human lymphocytes that are exposed to pulsed ultrasound conditions within the range typically employed in ultrasound Doppler measurements of fetal blood flow. Whole blood diluted with culture medium was exposed in vitro to 3.1 MHz pulsed ultrasound at spatial peak pulse average (SPPA) intensities from 15 to 135 W/cm2. Insonation for 5 min did not significantly alter the base level frequency of SCEs compared to that observed in sham-insonated controls. To avoid missing an effect, due to differing sensitivities of the division stages within the mitotic cycle, insonation was also applied for 24 hr to include one complete cell division cycle. No change in SCE was observed after this extended insonation at SPPA intensity of 33 W/cm2.

Cell Cycle↗
PubMed1986

Quantitative sonography.

The review presents a perspective on ultrasonic techniques which place numerical values on properties of tissue or physiological function. Two distinct approaches to tissue characterisation are identified and the various techniques employed are reviewed. The range of Doppler techniques currently in use or under development are described. The potential roles of the various techniques are discussed, using clinical results from the Ultrasonics Institute as a basis. Attenuation measurements show a considerable spread in results, but sound speed appears to correlate closely with the degree of fibrosis in liver and spleen. Other methods have been found useful in specialised areas. The use of pulsed Doppler with a resolution cell sufficiently large to encompass the entire vessel, in conjunction with B-mode imaging to determine geometry, permits volumetric flow measurements to be made in deep vessels and reveals previously inaccessible physiological data. The use of analysis techniques to provide quantitative information in the physiological state or function of tissue promises to add a new dimension to diagnostic ultrasound.

Doppler Effect↗
PubMed1986

[Breast sonography with the new water bath scanning technics].

At 1188 patients we investigated the value of sonography of the breast in the detection of malignancies. We used 2 automatic multitransducer water-bath scanners, at first the 3 MH Octoson, then System 1, a dedicated 4 MH water-bath breast scanner which allows for compound and simple scans in any scanning plane. The sensitivity for detection of 63 malignancies was 87%. Other pathologies were 18 fibroadenomas, 160 cysts, 6 abscesses, 2 fatty necroses, 2 papillomas, 9 prostheses, one of them broken. The difficulties associated with differential diagnosis in breast sonography are discussed in detail.

Abscess↗
PubMed1986

Quantitative common carotid artery blood flow: prediction of internal carotid artery stenosis.

Common carotid artery (CCA) blood flow was measured noninvasively with a pulsed Doppler duplex scanner modeled after the Octoson (Ultrasonics, Inc., No. Yonkers, N.Y.). The aim of the study was to determine normal values and to assess the accuracy of CCA flow as a predictor of internal carotid artery (ICA) stenosis. One hundred one people who did not have disease were studied; the overall mean flow rate was 395 +/- 79 ml/min (mean +/- S.D.). There was no significant correlation with age, height, or body surface area but there was with body weight (p less than 0.05). A statistically significant difference was evident between men (424 +/- 88 ml/min) and women (371 +/- 62 ml/min) (p less than 0.001). The intrasessional variation (S.D./mean) was 13% and the intersessional variation, 16%. No significant difference was seen between the sides. Ninety-two patients who had carotid angiography were studied and the flow rates compared with the degree of ICA stenosis on each side. The flow rate for mild ICA stenosis (1% to 39%) was 404 +/- 109 ml/min, for moderate stenoses (40% to 69%), 390 +/- 91 ml/min, and for severe stenoses (70% to 99%), 351 +/- 109 ml/min. There was a significant difference in flows only between mild and severe grades of stenosis of the ICA (p less than 0.01). With unilateral stenosis, comparison of flow values in the normal and affected sides showed the greatest discriminatory power when the absolute difference of flow values was taken (p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Duplex scanning of the portal vein and portasystemic shunts.

This article describes the preliminary findings of a Duplex ultrasound technique that enables the patency of the portal circulation and portosystemic shunt patency to be determined. In addition, the equipment allows the noninvasive measurement of quantitative rates of blood flow in these vessels. Portal vein flow was 952 +/- 273 ml/min in 10 normal subjects after an overnight fast and increased by 50% at 30 minutes in response to a standard 660-calorie liquid meal. Thirteen portosystemic shunts were scanned, and hemodynamic information was obtained from 10. Three of the four patients who had a Warren shunt performed 3 to 4 years earlier had portal vein occlusion. There is evidence of an increase in flow through the Warren shunt on feeding, suggesting a hemodynamic connection to the mesenteric side of the circulation. The apparatus, technique of examination, and the characteristics and difficulties with particular types of shunts are described.

Adult↗
PubMed1984

Temporal peak intensity as a critical parameter in ultrasound dosimetry.

The in vitro effect of microsecond pulses of ultrasound is studied in mammalian cells using two different biologic endpoints. The frequency of sister chromatid exchanges (SCE) is unchanged in Chinese hamster ovarian cells insonated with a stationary transducer for 1-30 minutes at an SPTA intensity of 0.1 W/cm2. Raising the temporal average intensity to 2 W/cm2 by increasing the pulse repetition frequency alone still has no effect, whereas a change in temporal peak intensity produces an increase in SCE after insonation for only 1 minute. From experiments involving aggregation of platelets in suspension around acoustically active hydrophobic pores, pulse duration is found to be a more effective factor than the pulse repetition frequency. Results of the two studies show the biologic response to be strongly dependent on temporal peak intensity and pulse duration, but weakly dependent on duration of exposure. The temporal average intensity as a singular dosage specification is considered to be a poor indicator of potential nonthermal bioeffects associated with microsecond pulses.

Animals↗
PubMed1983

Ultrasound exposure in diagnostic echography.

The output characteristics and spatial distribution of pulses were studied in static and real time B-mode imaging, and M-mode procedures to assess the ultrasound exposure occurring over the total examination area and at a single point tissue target during a diagnostic examination.

Biophysical Phenomena↗
PubMed1982

Ultrasonic exposure in static and real time echography.

Measurement of ultrasonic output from static and real time devices has shown both types of equipment to emit approximately the same amount of energy per pulse and the same peak instantaneous intensity. The major differences in exposure were related to the amount of energy used to produce an image, the total amount of energy used to perform an examination, and the amount of energy passing through a single point in tissue. the highest single point exposure occurred during static M-mode examinations when an energy exposure of 120 mJ per minute was measured. By comparison a real time B-mode examination resulted in a single point exposure of 0.018 mJ/echogram or 27 mJ/min. The single point exposure per echogram in a static examination was 0.12 mJ for a simple scan and 1.15 mJ for a compound scan with contact equipment, and 0.01 and 0.08 mJ for simple and compound scans using water path equipment.

Ultrasonics↗
PubMed1981

Fetal umbilical venous flow measured in utero by pulsed Doppler and B-mode ultrasound. I. Normal pregnancies.

Umbilical venous blood flow was measured with a pulsed Doppler unit, which was used in combination with a B-mode ultrasonic imaging system to permit location of the umbilical vein and measurement of its cross-sectional area. The accuracy and limitations of the method are discussed. Forty-seven normal fetuses with gestational ages ranging from 22 weeks to term were studied on a total of 61 occasions. Flow increased with gestational age until 36 weeks, was maximal between 37 and 38 weeks, then decreased during the last 2 weeks of pregnancy. Flow per unit of fetal weight was constant during pregnancy until 36 to 37 weeks, when a reduction occurred.

Blood Flow Velocity↗
PubMed1981

Shadowing and enhancement in ultrasonic echograms by reflection and refraction.

The action of reflection and refraction in producing shadows and enhancement in ultrasonic echograms behind cystic structures is well known, but the physical explanations usually used are incomplete. In this paper the emergent beam patterns for a number of cases are plotted and this data used to explain the shadows and enhancement observed. Cases are also illustrated of echoes displayed incorrectly within the shadow region and of reflectors within the shadow region displayed elsewhere. The use of the echographic appearances to assess the velocity of propagation in cystic structures is described.

Image Enhancement↗