Nuclear magnetic resonance spectroscopy of bovine ovarian follicular fluid at four selected times of the oestrous cycle

The objective of the study was to determine if nuclear magnetic resonance (NMR) spectral features of ovarian follicular fluid were correlated with the physiological status of follicles so that we could assess the feasibility of using NMR spectroscopy during assisted reproduction therapy. Thirty-five sexually mature, nullparious heifers were monitored by transrectal ultrasonography to assess their follicle wave status during the oestrous cycle. Ovariectomies were performed on Day 3 of wave 1 (D3W1, n = 10), Day 6 of wave 1 (D6W1, n = 9), Day 1 of wave 2 (D1W2, n = 9), or in the immediate preovulatory period of at least 17 days after ovulation (D≥17, n = 9). Follicle status was determined to be dominant or subordinate. Follicular fluid was extracted from the follicles and NMR spectra were collected. Principal components were extracted from ratios of line amplitudes and tested for effects of follicle status (dominant v. subordinate) and cycle time point (D1W3, D1W6, D1W2 and D≥17) using multivariate analysis of variance. For most line ratio combinations, main effects of status, time point and their interaction were found (P < 0.05). We concluded that NMR spectra may be used for the determination of ovarian follicle physiological status.

Systemic concentrations of hormones during the development of follicular waves in mares and women: a comparative study

Changes in systemic concentrations of FSH, LH, oestradiol and progesterone during the ovulatory follicular wave were compared between 30 mares and 30 women. Based on a previous study, the emergence of the future ovulatory follicle was defined as occurring at 13.0 mm in mares and 6.0 mm in women, and deviation in diameter between the two largest follicles was expected to begin at 22.7 mm in mares and 10.3 mm in women. Mean FSH concentrations were high in mares during the luteal phase, resulting from statistically identified FSH surges occurring in individuals on different days and in different numbers (mean, 1.5 +/- 0.2 surges/mare); the internadir interval was 3.9 +/- 0.3 days. In contrast, mean FSH in women was low during the luteal phase and increased to a prolonged elevation during the follicular phase. The prolonged elevation was apparent in each individual (internadir interval, 15.2 +/- 0.4 days). Changes in LH or oestradiol concentrations encompassing deviation were not detected in mares, but both hormones increased slightly but significantly between emergence and deviation in women. The hypothesis that a greater number of growing follicles causes a greater predeviation decrease in FSH was supported for mares (r, -0.39; P< 0.04), but a similar negative correlation (r, -0.36) was not significant in women. The hypothesis that the increase in oestradiol during the luteal phase in women was at least partly attributable to luteal-phase anovulatory follicular waves was not supported. Normalization of FSH concentrations to the day of emergence showed maximum value on the day of emergence with a significant increase and decrease on each side of emergence in both species. The day of expected deviation occurred 3 days after emergence during the decline in FSH in both species. These results indicated that the previously reported striking similarities in emergence and deviation between mares and women during the ovulatory follicular wave are associated with species similarities in the temporal relationships between follicle events and FSH concentration changes. Thus, mares may be useful research models for studying the role and mechanism of the action of FSH in emergence and deviation during the ovulatory follicular wave in women.

An application of Lacker’s mathematical model for the prediction of ovarian response to superstimulation

Introduction. A mathematical model of ovarian follicular growth is applied to the problem of predicting ovarian response in a superstimulation protocol. Methods. Fifty-four women enrolled in an ovarian superstimulation program of therapy for the amelioration of idiopathic infertility had their ovarian cycles synchronized by taking Demulen 30 for two weeks prior to the study. Daily ultrasonographic imaging, measurements of serum estradiol and doses of hMG began on day 5 after the patients stopped taking Demulen. The diameters of individual follicles were measured and followed daily. When the largest follicle attained a diameter of 19 mm, hCG was given to induce ovulation. Individual follicle growth data were fit to a mathematical model of ovarian follicle maturation and the resulting parameters were used to classify patients into low and high ovarian response groups. Results. The parameters computed from the mathematical model fit were found to be predictive of ovarian response with a sensitivity of 71% and a specificity of 70%. The parameters were also meaningful within the context of the original mathematical model and have value for determining how doses of hMG may be adjusted during the course therapy to increase the ovarian response in individuals. Conclusion. Mathematical modeling of ultrasonographically derived follicular growth data has significant potential for clinical application in ovarian superstimulation protocols. The method of fitting follicular growth data to a mathematical follicle maturation surface furthermore provides a straightforward approach for the characterization of ovarian follicular dynamics in general.

Form and function of the corpus luteum during the human menstrual cycle

OBJECTIVE

To characterize the growth and regression of the corpus luteum (CL) during an interovulatory interval (IOI) using serial transvaginal ultrasonography.

METHODS

Fifty healthy women of reproductive age with a history of regular menstrual cycles underwent daily transvaginal ultrasonography for one IOI. Measurements of luteal area and luteal numerical pixel value (NPV) were recorded each day after ovulation until the CL could no longer be detected. Blood was drawn every third day during the IOI to measure serum concentrations of progesterone and estradiol-17beta.

RESULTS

Corpora lutea were of two morphological types: those with a central fluid-filled cavity (CFFC) (78%) and those without (22%). Eighty-eight percent of women exhibited a CL containing a CFFC 2 days after ovulation, followed by 34% 13 days after ovulation and 2% 27 days after ovulation. Luteal area, progesterone concentration and estradiol concentration increased for approximately the first 6 days following ovulation followed by a subsequent decline. Luteal NPV decreased from days 1 to 11 and increased during days 11-16. Changes in luteal area, NPV, progesterone and estradiol concentrations did not differ in women with two versus three waves of follicular development.

CONCLUSIONS

Peak luteal function, as determined by maximum luteal area, progesterone concentration and estradiol concentration, is observed 6 days following ovulation. Luteal NPV is reflective of morphological and endocrinological changes in the CL. The development of a CFFC during luteinization is a normal physiological phenomenon. The CL can be detected, but is not functional, during the follicular phase of the menstrual cycle.

Ultrasound image attributes of human ovarian dominant follicles during natural and oral contraceptive cycles

BACKGROUND

Computer-assisted analyses were used to examine ultrasound image attributes of human dominant ovarian follicles that developed during natural and oral contraceptive (OC) cycles. We hypothesized that image attributes of natural cycle follicles would quantitatively differ from those in OC cycles and that OC cycle follicles would possess image attributes indicative of atresia.

METHODS

Dominant ovarian follicles of 18 clinically normal women were compared using transvaginal ultrasonography for the 7 days before ovulation during a natural cycle (n = 9) or the 7 days before peak estradiol in women using OC (n = 11). Follicles were analyzed using region and line techniques designed to compare the image attributes numerical pixel value (NPV), pixel heterogeneity (PH) and area under the curve (AUC).

RESULTS

NPV was higher in OC cycle follicles with region analysis and tended to be higher with line analysis (p = 0.005 and p = 0.06, respectively). No differences were observed in two other image attributes (AUC and PH), measured with either technique, between natural and OC cycle follicles.

CONCLUSION

The increased NPV value of OC cycle follicles and lack of differences in PH and AUC values between natural cycle and OC cycle follicles did not support the hypothesis that OC cycle follicles would show ultrasonographically detectable signs of atresia. Image attributes observed in OC cycle follicles were not clearly indicative of atresia nor were they large enough to preclude preovulatory physiologic status in OC cycle follicles.

Externally placed vs intravaginally positioned radio frequency coils for quantitative spin-spin relaxometry of ovarian follicular fluid

OBJECTIVE

To evaluate different imaging protocols, especially with respect to radio frequency (RF) receiver coil location, for their suitability in providing least squares derived quantitative T2 values of ovarian follicular fluid for investigations of basic ovarian physiology.

METHODS

The ovaries of 10 women were imaged via magnetic resonance imaging (MRI) using externally positioned and intravaginally placed RF receiver coils. Half-Fourier acquisition with single-shot turbo spin-echo (HASTE), multiple-echo T2, Dixon, turbo spin-echo, and 3-dimensional (3D) fast imaging with steady-state precession (FISP) and time-reversed FISP (PSIF) sequences were used. Quantitative T2 nuclear spin relaxation rate information from the ovarian follicles between data acquired with the external and intravaginal coils were compared. Additionally, the amount of ovarian follicle and corpora lutea structural detail visible was qualitatively assessed.

RESULTS

The T2 computations indicated that there was no difference in the follicular fluid T2 values or in the heterogeneity (spatial variance) of the T2 values between data acquired with the external RF coil and data acquired with the intravaginal RF coil. The best sequences for the visualization of ovarian internal structure were the 3D PSIF sequences and the multiple-echo T2-weighted images, confirming our earlier imaging work on excised cow ovaries.

CONCLUSION

It is best to use an externally placed RF coil for quantitative MRI study of ovarian physiology given the lack of difference in quantitative T2 information and the difficulty associated with imaging the ovaries using an intravaginal RF probe.

Ovarian follicular development is initiated during the hormone-free interval of oral contraceptive use

We evaluated ovarian follicular development in women during compliant use of oral contraceptives (OC). Thirty-six healthy women received: [35 microg ethinyl estradiol (21)/180 microg norgestimate (7), 215 microg norgestimate (7), 250 microg norgestimate (7)]; [30 microg ethinyl estradiol (21)/150 microg desogestrel (21)]; or [20 microg ethinyl estradiol (21)/100 microg levonorgestrel (21)] for 3 consecutive 28-day cycles. Transvaginal ultrasonography was performed every third day to monitor follicular development. If a follicle reached > or = 14 mm, ultrasonography was performed daily and blood drawn every other day to determine estradiol-17beta concentrations. Seventeen of 36 women (47%) grew follicles > or = 10 mm. Nine of the 17 women (53%) grew follicles > or = 14 mm, in association with increased serum concentrations of estradiol-17beta. Thirty-seven of 43 follicles > or = 10 mm (86%) emerged during the hormone-free interval (HFI). No ovulations were observed. Our results supported the hypothesis that follicular development to an ostensibly ovulatory diameter occurs during compliant OC use, in association with loss of endocrine suppression during the HFI.

Endometrial development in association with ovarian follicular waves during the menstrual cycle

OBJECTIVES

Waves of ovarian follicular development during the menstrual cycle have recently been documented in our laboratory. The objective of this study was to test the hypothesis that ultrasonographically detectable changes in the endometrium during the menstrual cycle would differ between women with two vs. three waves of ovarian follicular development and among women with different major and minor wave patterns of follicle growth.

METHODS

Fifty women of reproductive age (mean age +/- SD, 28.0 +/- 6.9 years) underwent daily transvaginal ultrasonography for one interovulatory interval (IOI). Ultrasonographic images of the endometrium were obtained each day, and measurements of endometrial area and perimeter (based on the shape of an ellipse, in the transverse plane) and thickness and pattern (in the sagittal plane) were recorded. Endometrial area, perimeter, thickness and pattern were compared between women with two and three waves of follicle development and among women with different minor and major wave patterns of follicular growth during the IOI.

RESULTS

Endometrial area, perimeter, thickness and pattern increased earlier during the follicular phase in women with two vs. three waves of follicular development. In women with two follicle waves, endometrial area and perimeter increased earlier in those with major major vs. minor major follicle wave patterns.

CONCLUSIONS

Ultrasonographically detectable changes in the endometrium occurred in association with follicle wave dynamics in women. Earlier development of the endometrium during the follicular phase in women with two vs. three follicle waves was attributed to an earlier increase in dominant follicle estradiol production.

Comparative study of the dynamics of follicular waves in mares and women

Deviation in growth rates of the follicles of the ovulatory wave begins at the end of a common growth phase and is characterized by continued growth of the developing dominant follicle (F1) and regression of the largest subordinate follicle (F2). Follicle diameters during an interovulatory interval were compared between 30 mares and 30 women, using similar methods for collecting and analyzing data. Follicles were tracked and measured daily by ultrasonography. Diameter at follicle emergence (mares, 13 mm; women, 6 mm) and the required minimal attained diameter for assessment of follicles (mares, 17 mm; women, 8 mm) were chosen to simulate the reported ratio between the two species in mean diameter of F1 at the beginning of deviation (mares, 22.5 mm; women, 10.5 mm). F1 emerged before F2 (P < 0.02) in each species, and the interval between emergence of the two follicles was similar (not significantly different) between species. Growth rate for F1 and F2 during the common growth phase was similar within species, and the percentage of diameter increase was similar between species. Proportionality between species in diameter of F1 at deviation (2.2 times larger for mares than for women) and at maximum preovulatory diameter (2.1 times larger) indicated that relative growth of F1 after deviation was similar between species. A predeviation follicle was identified in 33% of mares and 40% of women and was characterized by growth to a diameter similar to F1 at deviation but with regression beginning an average of 1 day before the beginning of deviation. The incidence of a major anovulatory wave preceding the ovulatory wave was not different between species (combined, 25%). Results indicated that mares and women have comparable follicle interrelationships during the ovulatory wave, including 1) emergence of F1 before F2, 2) similar length of intervals between sequential emergence of follicles within a wave, 3) similar percentage growth of follicles during the common growth phase, and 4) similar relative diameter of F1 from the beginning of deviation to ovulation. Similar follicle dynamics between mares and women indicate the mare may be a useful experimental model for study of folliculogenesis in women, with the advantage of larger follicle size.

Magnetic resonance diffusion imaging of ovarian masses: a first experience with 12 cases

OBJECTIVE

The objective of the study was to determine the feasibility of using apparent diffusion coefficient (ADC) measurement for the differential diagnosis of malignancy in ovarian masses.

MATERIALS AND METHODS

Twelve cases involving ovarian masses were imaged using spin echo diffusion magnetic resonance imaging (MRI). Five cases involved malignant ovarian masses, on the basis of postoperative histologic examination, and the rest involved benign masses. The ovarian masses were imaged in vivo (10 cases) before surgery and ex vivo (8 cases) after surgical resection. Diffusion-weighted data were corrected for motion using the phase data from unweighted data in nine cases. Multifactorial analysis of variance was used to evaluate the effects of malignancy, location (in vivo versus ex vivo), and motion correction on the measurement of ADC intensity and texture.

RESULTS

Motion correction caused an undesirable spatial smoothing of the ADC maps and a significant interaction (p=0.047) was found between location and motion correction. ADC value (p=0.028) and texture (p=0.001) differences were found between malignant and nonmalignant ovarian masses.

CONCLUSION

Measurement of ADC intensity and texture has the potential to differentially diagnose malignancy in individual ovarian masses if the problem of image motion artifact can be eliminated through the use of faster imaging sequences.

Ultrasonographic evaluation of the pre-pubertal development of the reproductive tract in beef heifers

To study the development of the reproductive tract in heifers, the ovaries, uterus, cervix and vagina were examined by transrectal ultrasonography every 2 weeks, from 2 to 60 weeks after birth. First ovulation occurred at 63.7 +/- 1.1 weeks of age. Ovarian dimensions increased rapidly from 2 to 14 weeks of age, and increased again after 34 weeks of age (P<0.05). The size of the largest ovarian follicles increased from 8 to 14 weeks of age, from 38 to 42 weeks of age, and finally from 52 to 60 weeks of age (P<0.05). The number of follicles > or =3 mm in diameter tended to increase from 6 to 14 weeks of age (P<0.10) and increased significantly from 6 to 60 weeks of age (P<0.05). Mean numerical pixel values of the ovarian images decreased from 4 to 26 weeks of age, and then rose to 44 weeks of age (P<0.05). Diameter of the uterine body, cervix and vagina increased from 2 to 20-24 weeks of age, and again after 32 weeks of age (P<0.05). Mean numerical pixel values for the uterus and vagina decreased initially (uterus: 4-8 weeks and vagina: 6-22 weeks of age) and then increased (uterus: 14-42 weeks and vagina: 22-32 weeks of age; P<0.05). Pixel heterogeneity showed a consistent peak at 20-22 weeks of age for the uterus, cervix and vagina (P<0.05). In summary, in the heifer calf, the marked growth of the reproductive tract in the first few months of age, and prior to first ovulation, reflects phases of increased ovarian follicle (> or =3 mm in diameter) numbers and size. Ultrasonographic image analysis revealed patterns of numerical pixel values and heterogeneity that may be useful in determining important stages of growth and differentiation of the reproductive system.

Ovarian follicular development during the use of oral contraception: a review

Over the past 40 years, alterations to the composition of oral contraceptives (OCs) have been made in attempts to reduce adverse effects and to improve patient compliance while maintaining contraceptive efficacy. However, there is growing evidence to indicate that reducing the estrogen dose to minimize adverse effects may have compromised the degree of hypothalamo-pituitary-ovarian suppression, particularly during the hormone-free interval (HFI) or following missed doses. Follicle development during OC use appears to occur in association with a loss of endocrine suppression during the HFI. This information provides a rationale for reducing or eliminating the HFI in OC regimens. There is also evidence for an increased risk of follicle development and ovulation in women who use delayed OC initiation schemes, such as the "Sunday Start" method. It is not currently known why some follicles ovulate during OC use while others regress or form anovulatory follicle cysts. Continued research about follicle development during OC use would provide insight into understanding the precise mechanisms of action underlying combined OCs, as well as those of continuous OC formulations and emergency contraceptive regimens.

Promise of new imaging technologies for assessing ovarian function

Advancements in imaging technologies over the last two decades have ushered a quiet revolution in research approaches to the study of ovarian structure and function. The most significant changes in our understanding of the ovary have resulted from the use of ultrasonography which has enabled sequential analyses in live animals. Computer-assisted image analysis and mathematical modeling of the dynamic changes within the ovary has permitted exciting new avenues of research with readily quantifiable endpoints. Spectral, color-flow and power Doppler imaging now facilitate physiologic interpretations of vascular dynamics over time. Similarly, magnetic resonance imaging (MRI) is emerging as a research tool in ovarian imaging. New technologies, such as three-dimensional ultrasonography and MRI, ultrasound-based biomicroscopy and synchrotron-based techniques each have the potential to enhance our real-time picture of ovarian function to the near-cellular level. Collectively, information available in ultrasonography, MRI, computer-assisted image analysis and mathematical modeling heralds a new era in our understanding of the basic processes of female and male reproduction.

Characterization of ovarian follicular wave dynamics in women

A wave phenomenon of ovarian follicular development in women has recently been documented in our laboratory. The objective of the present study was to characterize follicular waves to determine whether women exhibit major and minor wave patterns of follicle development during the interovulatory interval (IOI). The ovaries of 50 women with clinically normal menstrual cycles were examined daily using transvaginal ultrasonography for one IOI. Profiles of the diameters of all follicles >or=4 mm and the numbers of follicles >or=5 mm were graphed during the IOI. Major waves were defined as those in which one follicle grew to >or=10 mm and exceeded all other follicles by >or=2 mm. Minor waves were defined as those in which follicles developed to a diameter of <10 mm and follicle dominance was not manifest. Blood samples were drawn to measure serum concentrations of estradiol-17beta, LH, and FSH. Women exhibited major and minor patterns of follicular wave dynamics during the IOI. Of the 50 women evaluated, 29/34 women with two follicle waves (85.3%) exhibited a minor-major wave pattern of follicle development and 5 women (14.7%) exhibited a major-major wave pattern. Ten of the 16 women with three follicle waves (62.5%) exhibited a minor-minor-major wave pattern, 3 women (18.8%) exhibited a minor-major-major wave pattern, and 3 women (18.8%) exhibited a major-major-major wave pattern. Documentation of major and minor follicular waves during the menstrual cycle challenges the traditional theory that a single cohort of antral follicles grows only during the follicular phase of the menstrual cycle.

Clinical use of sonohysterography in the evaluation of infertility

Assessment of tubal patency and evaluation of the uterine cavity should be part of all infertility investigations. Sonohysterography (SHSG), also referred to as saline-enhanced ultrasonography, is being used with increasing frequency for investigation of infertility and other gynaecological indications. Sonohysterography is similar to hysterosalpingography (HSG) in its effectiveness for evaluating tubal patency, and superior to HSG for assessing intrauterine abnormalities. Advantages of SHSG over HSG include the ability to assess extrauterine structures, lack of ionizing radiation, and often better tolerability by the woman being examined. Sonohysterography can offer detailed assessment of the female pelvis, and has the potential to replace HSG as a routine, first-line infertility investigation. This paper discusses the technique and indications for SHSG, and reviews its use in infertility investigation, in particular in the assessment of the uterine cavity and tubal patency.

Luteogenesis in cyclic ewes: echotextural, histological, and functional correlates

To date, it has not been possible to detect corpus luteum (CL) by ultrasonography, immediately following ovulation, in the ewe. Early CL detection is essential to be able to relate luteal outcome to the developmental pattern of the ovulated follicle and to confirm ovulation. Image analysis of the CL may be useful in providing a noninvasive picture of CL differentiation and function. The present study was designed to use high-resolution ultrasonography to monitor and to correlate the echotextural, histological, and functional attributes of the developing ovine CL from Days 1 to 3 after ovulation. Ten ewes underwent twice-daily transrectal ultrasonography and blood sampling from the day of synchronized estrus. Ewes were ovariectomized at 12-24, 36-48, and 60-72 h after ovulation. Ovaries collected were scanned in a water bath before processing for histology. Ultrasonographic images of CL were analyzed for echotexture. Histological sections were analyzed for the percentage area of the CL occupied by blood clot or luteal tissue. Serum samples were analyzed for progesterone concentration. Numerical pixel value, heterogeneity, and percentage of the CL occupied by blood clot declined (P<0.05) from 12-24 to 60-72 h after ovulation. Luteal area and serum progesterone concentration increased (P<0.05) from 12-24 to 60-72 h. The results indicated that it was possible to visualize developing CL as early as 12-24 h after ovulation in the ewe. Echotexture of the CL was closely associated with its morphological and functional characteristics; image analysis holds promise for noninvasive monitoring of CL differentiation and growth.

A new model for ovarian follicular development during the human menstrual cycle

OBJECTIVE

To evaluate changes in ovarian follicle dynamics during the human menstrual cycle to test the hypothesis that folliculogenesis occurs in a wave-like fashion.

DESIGN

Prospective longitudinal study.

SETTING

Healthy volunteers in an academic research environment.

PATIENT(S)

Fifty healthy women of reproductive age (range 19-43 years) with a history of regular menstrual cycles not taking medications known to interfere with reproductive function were evaluated.

INTERVENTION(S)

Transvaginal ultrasonography was performed daily for one interovulatory interval (IOI).

MAIN OUTCOME MEASURE(S)

Changes in the diameter and number of follicles > or =5 mm were evaluated.

RESULT(S)

Sixty-eight percent of women exhibited two waves of follicle development during the IOI and 32% exhibited three waves. Waves were characterized by an increase and subsequent decrease in the number of follicles > or =5 mm occurring in association with the growth of > or =2 follicles to > or =6 mm. A day effect and day by wave interaction were detected in the mean diameter of the largest three follicles and the number of follicles > or =5 mm.

CONCLUSION(S)

The follicular wave phenomenon in women provides a new model for ovarian function during the menstrual cycle and will improve our understanding of the ovarian response to fertility and hormonal contraceptive regimens.

Ortho Evra/Evra versus oral contraceptives: follicular development and ovulation in normal cycles and after an intentional dosing error

OBJECTIVE

To compare the effects of the contraceptive patch to oral contraceptives (OCs) on follicular size and incidence of ovulation in normal cycles and after dosing errors.

DESIGN

Randomized, open-label.

SETTING

Twelve centers.

PATIENT(S)

One hundred twenty-four ovulatory women.

INTERVENTION(S)

Subjects received either the patch (groups 1 and 2) or one of three OCs. Correct dosing occurred in cycles 1, 2, 3, and 5. The following dosing errors were planned during cycle 4, a shortened 10-day cycle: [1] patch group 1 subjects wore one patch for 10 consecutive days; [2] for patch group 2 and OC subjects, 7 dosing days were followed by 3 drug-free days.

MAIN OUTCOME MEASURE(S)

Follicular size, as determined at each cycle by the maximum mean follicular diameter.

RESULT(S)

After a 3-day dosing error, follicular size was significantly smaller in the patch group (mean, 7.0 mm) vs. each OC group (range of means, 11.8-17.1 mm). Similar results were seen after proper dosing. The incidence of ovulation was significantly lower for the patch users than for women using OCs.

CONCLUSION(S)

Follicular size and incidence of ovulation were significantly reduced among contraceptive patch users compared with women using OCs in normal cycles and after planned dosing errors.

Magnetic resonance image attributes of the bovine corpus luteum during development and regression

To determine whether magnetic resonance (MR) image attributes of the corpus luteum (CL) reflect its physiologic status at different phases of the bovine ovarian cycle, we analyzed the numerical pixel values (NPVs), relaxation rates, proton densities (PDs), and apparent diffusion coefficients (ADCs) from T(1)-, T(2)-, and diffusion-weighted in vitro images and maps of the CL acquired at defined phases of luteal function. Ovaries were removed and serum samples taken on days 3, 6, and 10, or >/=17 (day 0 = ovulation), representing metestrus (n = 10), early diestrus (n = 7), mid-diestrus (n = 9), and proestrus (n = 7), respectively. Regions of interest (ROIs) in each quadrant of the CL (which occupied at least 20% of the quadrant) were selected for analysis. Three MR image slices were analyzed: the slice with the greatest cross-sectional area of the CL, and the slices acquired immediately before and after that slice. The mean NPVs of the CL in T(1)-weighted images increased at each phase from metestrus (1,104 +/- 40 msec) to early diestrus (1,119 +/- 77 msec), to late diestrus (1,206 +/- 43 msec) and proestrus (1446 +/- 80 msec; P < 0.001). The mean NPVs in T(1)-weighted images were higher in regressing CL (proestrous) than in any other phase (P < 0.002). Grayscale heterogeneity of CL in T(1)-weighted images tended to increase during regression (P < 0.07). Regressing CL (proestrus) exhibited higher T(1)-weighted mean NPVs (P < 0.01) and tended to have greater heterogeneity (P < 0.06) than growing (metestrus) and mature (diestrus) CL, even though similar progesterone concentrations were observed. The increased brightness and heterogeneity of regressing CL in T(1)-weighted images appeared to be correlated with increased connective tissue and triglyceride content and decreased vascularity. It is anticipated that diagnostic markers for luteal viability and atresia in the in vitro bovine model will be applied to in vivo studies in women.

Imaging the endometrium: are there predictors of uterine receptivity?

Ultrasound imaging technology brings new insight to cyclic changes in the endometrium and offers the potential to assess the probability of embryo implantation in natural and assisted reproduction cycles. However, the data reported are diverse and frequently conflict in their analysis and conclusions. This review examines imaging techniques used for endometrial evaluation, including grey-scale ultrasonography and colour-flow, power-flow, and spectral Doppler interrogation of the uterine vasculature. New techniques being used for uterine assessment, such as computer-assisted image analysis, three-dimensional ultrasonography, and magnetic resonance imaging, are also discussed. Each of these techniques is under active investigation and has the potential to provide rapid, noninvasive endometrial evaluation. Currently, there is reasonable certainty that women with heterogeneous endometrial linings of less than 6 mm will rarely conceive, and that endometrial contractions, or lack thereof, play some role in the successful establishment of pregnancy, even though this role has not yet been identified. Given the set of new imaging technologies available, it is feasible to expect that visual assessments will someday be used as predictors of uterine receptivity.

Ultrasound image characteristics of ovarian follicles in relation to oocyte competence and follicular status in cattle

Assessment of the quality of the female gamete has become paramount for in vitro procedures. There is a need to identify reliable indicators of oocyte competence and develop a simple, non-invasive method to assess competence. The aim of this study was to investigate the relationships among ultrasonographic attributes of a follicle, its stage of development and the competence of the oocyte that it contains. We tested the hypotheses that follicular echotexture characteristics are related to: (1) the phase of development of the follicle, (2) the presence of the corpus luteum (CL) and/or the dominant follicle in the ovary, and (3) developmental competence of cumulus oocyte complexes (COC) from the same ovary. Crossbred beef cows (n=143), age 4-14 years, were given a luteolytic dose of dinoprost to cause ovulation. Ultrasound-guided ablation of all follicles > or = 4mm was done 8 days later to induce new follicular wave emergence during a luteal phase. Ultrasonographic images of dominant follicles and the three largest subordinate follicles (n=402 follicles; 84 cows) were acquired on Days 2, 3, 5 or 7 of the follicular wave (Day 0: wave emergence), i.e. growing, early-static, late static, and regressing phases of subordinate follicle development, respectively. From a subset of these animals (n=33), ovaries were collected within 30 min of slaughter and COC from subordinate follicles > or = 3mm underwent in vitro maturation, fertilization and culture to the blastocyst stage.Image analysis revealed differences in echotexture between dominant and subordinate follicles among Days 2-7 of the follicular wave. Images of dominant and subordinate follicles at Day 7 of the wave displayed consistently lower grey-scale values (P<0.05) in the peripheral antrum, follicular wall and perifollicular stroma than all other days. Follicle images displayed a consistent pattern of variation in echotexture among follicular phases. Data did not support the hypothesis of a local effect of the CL or dominant follicle on follicular echotexture. Echotexture values of the perifollicular stroma were lower in ovaries that did not produce embryos compared to ovaries that produced embryos. Our results showed that the changes in follicular image attributes are consistent with changes in follicular status. The sensitivity of the technique is not yet sufficient for use in a diagnostic setting, but results provide rationale for further development of image analysis as a tool for evaluating oocyte competence in situ.

Magnetic resonance image attributes of the ovarian follicle wall during development and regression

We analyzed image characteristics in T(1)-, T(2)-, and diffusion-weighted in vitro magnetic resonance (MR) images acquired at predefined stages of the ovarian cycle in 36 heifers to test the hypothesis that MR image attributes of the follicle wall reflect the physiologic status of ovarian follicles (viable, atretic, dominant, subordinate). Numerical pixel values (NPV), standard deviation of pixel values (heterogeneity), and area under the curve were used to assess images of follicle walls. Pixel values of the wall were used to calculate a regression line from which intercept, slope, and coefficient of determination were calculated. In T(1) images, NPV of dominant follicles were less likely to fit a regression line at the preovulatory phase than at any other phase (P < 0.1). Preovulatory dominant follicles had lower area under the curve in diffusion-weighted images than early and late static dominant follicles of the anovulatory wave (P < 0.02). Subordinate follicles in the presence of a preovulatory dominant follicle had lower mean NPV in T(1)- and T(2)-weighted images and lower intercepts in T(1)-weighted images than subordinate follicles of the anovulatory wave (P < 0.02). Early atresia of dominant follicles was identified at the late static phase by greater area, mean NPV, and slope in T(2)-weighted images (P < 0.02). Preovulatory dominant follicles had poor fit of NPV to a regression line in T(1)-weighted images and lower area under the curve in diffusion images. Atretic follicles had brighter walls with more acute transitions from follicular fluid to stroma in T(2)-weighted images and more heterogeneous walls in diffusion images. The MR image attributes of the follicle wall reflected the physiologic status of dominant and largest subordinate follicles.

Relationships among scrotal and testicular characteristics, sperm production, and seminal quality in 129 beef bulls

Standard breeding soundness examinations plus measurement of scrotal surface temperature (SST), internal/scrotal testicular temperatures, testicular ultrasonographic echotexture, daily sperm production, and epididymal sperm reserves were conducted on 129, 16-month-old crossbred beef bulls. There were significant positive linear correlations between SST and internal scrotal/testicular temperatures, a positive linear regression (P < 0.06) of bottom SST with the incidence of secondary sperm defects, but a negative linear regression (P < 0.01) with the incidence of primary sperm defects. Testicular echotexture had a positive linear regression with daily sperm production (P < 0.002) and testicular tone had a negative linear regression (P < 0.008) with epididymal sperm reserves. Scrotal circumference had a positive linear regression (P < 0.04) with the percentage of progressively motile sperm, a negative linear regression (P < 0.1) with the incidence of primary sperm defects, and a positive linear regression (P < 0.0001) with epididymal sperm reserves. In addition to seminal quality and scrotal circumference, testicular ultrasonographic echotexture has considerable promise for augmenting breeding soundness examinations of bulls.