Comparison of magnetic resonance imaging and ultrasound in evaluating follicular and endometrial development throughout the normal cycle

MRI for Diagnosing Intrauterine Adhesions

OBJECTIVES

To prospectively assess the diagnostic accuracy of MRI and transvaginal ultrasound (TVS) as well as the prognostic value of MRI for intrauterine adhesions (IUAs), using hysteroscopy as the reference standard.

DESIGN

Prospective observational study.

SETTING

Tertiary medical centre.

PATIENT(S)

Ninety-two women with amenorrhea, hypomenorrhea, subfertility, or recurrent pregnancy loss who underwent MRI and in whom Asherman's syndrome was suspected upon TVS.

INTERVENTION(S)

MRI and TVS were conducted approximately 1 week before hysteroscopy.

METHODS

Ninety-two patients suspected of having Asherman's syndrome were examined by MRI and TVS within 7 days of an upcoming hysteroscopy. All hysteroscopy procedures were performed during the early proliferative phase of the menstrual cycle. All hysteroscopic diagnoses were performed by an experienced expert. All MRIs were read by 2 experienced, blinded radiologists.

RESULTS

MRI was highly accurate (94.57%), sensitive (98.8%), and specific (42.9%) for diagnosing IUAs with a positive predictive value of 95.5% and a negative predictive value of 75%. The diagnostic values of MRI and TVS were significantly different according to McNemar tests. Junctional zone signal and junctional zone alterations correlated with the stage of IUAs.

CONCLUSION

MRI is markedly superior to TVS in terms of diagnostic accuracy for IUAs, with total agreement with hysteroscopic findings. However, the main advantage of MRI is that, unlike TVS and hysterosalpingography, it can be used to assess the risk of hysteroscopy and to predict postoperative recovery and future pregnancy based on the uterine junctional zone.

A Study on the Prediction of Reproductive Outcomes in Frozen Embryo Transfer Cycles by Calculating the Volume of Uterine Junctional Zone with Three-Dimensional Ultrasound

PURPOSE

To prospectively study the influence of the volume of the uterine junctional zone (JZ) as a novel predictor of reproductive outcomes in frozen embryo transfer cycles.

METHODS

Among the first 30 patients, intra- and interobserver repeatability was evaluated and expressed as a coefficient of repeatability. The same classification system was used to evaluate the JZ of 142 infertility patients undergoing in vitro fertilization (IVF). Ultrasonography was performed on the day before transplantation. The three-dimensional (3D) volume images were then analyzed to obtain the volume of the endometrium (EV), the average thickness of the JZ on the coronal plane, and the volume of the JZ (JZV). The JZV was then divided by the EV. These parameters were compared with the outcomes of clinical pregnancy.

RESULTS

The 3D image showed that the JZ achieved a good intra- and interobserver consistency (k = 0.862, k = 0.694). The total pregnancy rate was 47%. There was a highly significant difference between pregnant and non-pregnant women with respect to age (p < 0.001), JZV (p = 0.003), and JZV/EV (p < 0.001) on the day before transplantation. Age and JZV/EV were independent factors for predicting the success of IVF transplantation (p = 0.010, p = 0.016). The area under the ROC curve of JZV/EV in predicting clinical pregnancy was 0.688, the cut-off value was 0.54, the sensitivity was 83.8%, and the specificity was 50.0%.

CONCLUSION

Age and JZV/EV are independent factors for predicting the success of frozen embryo transfer cycles in IVF. A smaller JZV/EV was more beneficial for clinical pregnancy.

Uterine junctional zone and adenomyosis: comparison of MRI, transvaginal ultrasound and histology

The uterine junctional zone is the subendometrial area in the myometrium that contributes to peristalsis and aids in spermatozoa and blastocyst transport. Alterations in the appearance of the junctional zone on transvaginal sonography (TVS) or magnetic resonance imaging (MRI) are associated with adenomyosis. The lack of standardization of description of its appearance and ill-defined boundaries on both histology and imaging hamper understanding of the junctional zone and limit its role in the diagnosis of adenomyosis. The objectives of this review were to investigate the accordance in definition of the junctional zone across different diagnostic approaches and to examine how imaging findings can be linked to histological findings in the context of diagnosis of adenomyosis. A comprehensive literature review was conducted of articles describing the appearance on imaging and the histological structure of the uterine junctional zone. Our review suggests that the junctional zone is distinguished from the middle and outer myometrium by gradual changes in smooth-muscle cell density, extracellular space, connective tissue, water content and vascular properties. However, while the signal intensity from the junctional zone to the middle myometrium changes abruptly on MRI, the histopathological changes are gradual and its border may be difficult or impossible to distinguish on two-dimensional TVS. Moreover, the thickness of the junctional zone measured on MRI is larger than that measured on TVS. Thus, these two imaging modalities reflect this zone differently. Although a thickened junctional zone is often used to diagnose adenomyosis on MRI, the presence of adenomyosis can be described more accurately as interruptions of the junctional zone by endometrial tissue, which leads to direct signs on imaging such as subendometrial lines and buds on two- and three-dimensional TVS or bright foci on MRI. The histopathological criteria for diagnosis are based on enlargement of the uterus with severe adenomyosis, and might not reflect its early stages. Clinicians should be aware that findings on MRI cannot be extrapolated readily to ultrasound. An understanding of this is necessary when investigating the uterine junctional zone as a functional unit and the association between visualization of direct features of adenomyosis in the junctional zone and clinical symptoms. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

A Review and Case Study of 3D Imaging Modalities for Female Amniote Reproductive Anatomy

Recent advances in non-invasive imaging methods have revitalised the field of comparative anatomy, and reproductive anatomy has been no exception. The reproductive systems of female amniotes present specific challenges, namely their often internal "hidden" anatomy. Quantifying female reproductive systems is crucial to recognising reproductive pathologies, monitoring menstrual cycles, and understanding copulatory mechanics. Here we conduct a review of the application of non-invasive imaging techniques to female amniote reproductive anatomy. We introduce the commonly used imaging modalities of computed tomography (CT) and magnetic resonance imaging (MRI), highlighting their advantages and limitations when applied to female reproductive tissues, and make suggestions for future advances. We also include a case study of micro CT and MRI, along with their associated staining protocols, applied to cadavers of female adult stoats (Mustela erminea). In doing so, we will progress the discussion surrounding the imaging of female reproductive anatomy, whilst also impacting the fields of sexual selection research and comparative anatomy more broadly.

Significance of endometrial thickness change after human chorionic gonadotrophin triggering in modified natural cycles for frozen-thawed embryo transfer

Background

Peak endometrial thickness (EMT), measured on the end of follicular phase or early luteal phase, is the most widely used marker for endometrial receptivity during infertility treatment. However, the clinical significance of follicular-to-luteal EMT change remains unclear. We aimed to study whether the change of EMT between the day of human chorionic gonadotrophin (hCG) triggering and the day of frozen-thawed embryo transfer (FET) has any influence on pregnancy outcomes in modified natural cycles (mNCs).

Methods

This was a retrospective cohort study of 2,768 regular ovulatory women who underwent their first mNC-FET cycles from January 2011 to June 2015. Patients were divided into three groups according to the percentage change of EMT from the hCG triggering day to the FET day: >5% decrease (n=405), ±5% plateau (n=1,259) and >5% increase (n=1,104). The main outcome measure was live birth rate.

Results

Live birth rates were 41.9%, 39.8% [crude odds ratio (cOR) 0.91, 95% CI, 0.73–1.15) and 42.4% (cOR 1.02, 95% CI, 0.87–1.20) in the EMT plateau, decrease and increase groups, respectively (P=0.649). Multiple regression analysis did not alter the finding after controlling for a variety of confounders. Compared with the post-trigger EMT plateau group, the adjusted OR of live birth was 0.88 (95% CI, 0.69–1.12) in the decrease group and 1.05 (95% CI, 0.88–1.25) in the increase group. Similarly, no significant associations were observed before or after adjustment between EMT change and other pregnancy outcomes including positive hCG test, clinical pregnancy, early miscarriage and ongoing pregnancy.

Conclusions

EMT change from hCG triggering to embryo transfer was not associated with pregnancy chances in mNC-FET cycles. This reassuring finding should provide guidance for physicians and patients when confronted with EMT decrease on the transfer day.

Value of endometrial thickness change after human chorionic gonadotrophin administration in predicting pregnancy outcome following fresh transfer in vitro fertilization cycles

PURPOSE

To study whether the change of endometrial thickness (EMT) between the day of human chorionic gonadotrophin (hCG) administration and the day of embryo transfer has any impact on pregnancy outcome in fresh in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles.

METHODS

This single-center retrospective cohort study included 2620 patients undergoing their first consecutive autologous IVF/ICSI cycles from January 2003 to December 2012. Patients were categorized into three groups based on the percentage change of post-hCG EMT: > 10% decrease, ± 10% plateau and > 10% increase. The primary outcome was live birth rate.

RESULTS

Live birth rates were similar in the EMT decrease, plateau and increase groups (27.4% [174/635], 29.7% [300/1010] and 27.6% [269/975]; P = 0.649). Compared with the plateau group, both EMT decrease (crude odds ratio [cOR] 0.89, 95% confidence interval [CI] 0.72-1.11) and increase (cOR 0.90, 95% CI 0.74-1.10) on the day of transfer did not affect the likelihood of live birth. The non-significant association was maintained after controlling for major confounding factors, with the adjusted OR being 0.92 (95% CI 0.73-1.16) and 0.92 (95% CI 0.75-1.13) for the decrease and increase groups, respectively.

CONCLUSION

EMT change after hCG administration did not provide significant prognostic information for pregnancy outcome in fresh IVF/ICSI cycles. This finding should offer reassuring information for patients with decreased EMT on the day of embryo transfer while questioning the necessity of EMT re-measurement prior to transfer as a routine practice.

Pathophysiologic mechanisms by which adenomyosis predisposes to postpartum haemorrhage and other obstetric complications

Adenomyosis is characterized by the presence of ectopic endometrium within the myometrium. This features lead to structural changes in the surrounding myometrium and endometrium resulting also in functional changes. Alterations in the myometrium are suspected to lead to defective remodeling of spiral arteries during the early stages of decidualization resulting in altered vascular resistance and defective placentation. These alterations could play a common part in the association between adenomyosis and major obstetric complications. Latest epidemiological studies show that adenomyosis is associated with preterm birth, preeclampsia, IUGR and increased caesarean section rates, but very little is known of any underlying mechanism linking postpartum hemorrhage and adenomyosis. It is our opinion that adenomyosis may increase the risk of postpartum hemorrhage through several mechanisms that will be further clarified. Women with adenomyosis may require specific management during pregnancy and may benefit from wider understanding of the pathological mechanisms associated with this disease process.

Expression of Cannabinoid Receptors in Myometrium and its Correlation With Dysmenorrhea in Adenomyosis

The myometrium, especially the junctional zone (JZ), is now well documented to have a role in the pathogenesis of adenomyosis. Cannabinoid receptors have been shown to participate in the establishment of endometriosis and its pain perception. However, its relation to adenomyosis has not been identified yet. The aim of this study was to investigate the expression of cannabinoid receptor type I (CB1) and type II (CB2) in myometrium of uteri with and without adenomyosis and determine the correlation between their levels and clinical parameters of adenomyosis. We collected tissue samples of JZ and the outer myometrium from 45 premenopausal women with adenomyosis and 34 women without adenomyosis. CB1 and CB2 messenger RNA (mRNA) and protein expression levels were evaluated by the use of Western blotting and real-time quantitative polymerase chain reaction from all samples. Clinical information on the severity of dysmenorrhea and other data were collected. We found both CB1 and CB2 mRNA and protein levels in women with adenomyosis were significantly higher than those of controls, and CB1 expression levels in JZ were positively correlated with the severity of dysmenorrhea. These data suggest that cannabinoid receptor CB1 may be involved in the pathogenesis of dysmenorrhea in adenomyosis and may be a potential therapeutic target.

The pathophysiology of uterine adenomyosis: an update

The diagnosis of adenomyosis using noninvasive techniques such as vaginal ultrasounds and magnetic resonance has clear clinical applications and has renewed the interest in the pathogenesis of uterine adenomyosis. However, the research remains hampered by the lack of consensus on the classification of lesions. Magnetic resonance imaging and transvaginal ultrasound have comparable diagnostic accuracy. Minimal interventional biopsy techniques have recently been introduced. This article reviews human and animal studies and provides an update on the pathophysiology of adenomyosis. Recent views on the pathogenesis and links with endometriosis are discussed.

Inter- and intraobserver variability in three-dimensional ultrasound assessment of the endometrial-myometrial junction and factors affecting its visualization

OBJECTIVE

To assess the inter- and intraobserver variability of three-dimensional (3D) ultrasound assessment of the endometrial-myometrial junction (EMJ), and to assess demographic and physiological factors that affect the quality of its imaging.

METHODS

Women attending our gynecology clinic, who were deemed to have normal uteri on transvaginal ultrasound examination, were enrolled in this prospective study. They underwent 3D volume acquisition of the entire uterus in order to acquire a coronal view of the organ. Visualization of EMJs was classified as optimal, satisfactory or unsatisfactory. In order to assess the intra- and interobserver variabilities of the classification system, the volumes were classified by two independent observers on two separate occasions. The same classification system was then used to evaluate the EMJs of 101 women who were deemed to have normal uteri on transvaginal ultrasound examination. The results were correlated with age, parity, stage of cycle, menopausal status and endometrial thickness in order to assess whether any of these factors affect visualization of the EMJ.

RESULTS

A total of 30 uterine volumes were examined in the first analysis. Both the inter- and intraobserver variability were good (kappa values of 0.77 and 0.83). Of the 101 EMJs assessed in the second analysis, 47 were classified as optimal, 42 as satisfactory and 12 as unsatisfactory. Endometrial thickness was positively associated with EMJ visualization and parity was negatively associated with EMJ visualization.

CONCLUSIONS

Assessment of EMJ visualization has both good inter- and intraobserver variability in women with normal uteri. Parity and endometrial thickness have contrasting, statistically significant, effects on visualization of the EMJ.

Infertility and adenomyosis

Classically, the diagnosis of adenomyosis has only been possible on a hysterectomy specimen, usually in women in their late fourth and fifth decades, and, therefore, evaluating any relationship with infertility was simply not possible. As a consequence, to this day, no epidemiologic data exists linking adenomyosis to a state of subfertility. Today, new imaging techniques have enabled a noninvasive diagnosis at a much earlier time and a number of single-case or small series reports have appeared showing that medical, surgical, or combined treatment can restore fertility in women with adenomyosis, an indirect proof of an association. At the functional level, several anomalies found in the so-called junctional zone, or inner myometrium, in adenomyosis patients have been shown to be associated with poor reproductive performance, mainly through perturbed uterine peristalsis. Additional evidence for an association comes from experimental data: in baboons, adenomyosis is associated with lifelong primary infertility, as well as to endometriosis. Finally, indirect proof comes from studies of the eutopic and ectopic endometrium in women with adenomyosis proving the existence of an altered endometrial function and receptivity. In conclusion, sufficient indirect proof exists linking adenomyosis to infertility to warrant systematic clinical studies.

Adenomyosis and infertility

Today an accurate diagnosis of adenomyosis can be made thanks to progress in imaging techniques: sonography and magnetic resonance imaging (MRI). This has made it possible to clinically correlate the presence of adenomyosis to infertility. At the same time, a series of pathogenetic hypotheses have been presented to explain this correlation. First, the identification of the myometrial junctional zone (JZ) and of its disruption and thickening has been linked to poor reproductive performance mainly through perturbed uterine peristalsis, a phenomenon that originates exclusively from the JZ in the nonpregnant uterus. In addition, a number of biochemical and functional alterations in both eutopic and heterotopic endometrium in women with adenomyosis have now been found to lead to lower receptivity, indicated by the presence of 'implantation marker' defects. In these patients there is also an altered decidualization and abnormal concentrations of intrauterine free radicals. All these abnormalities in the endometrial environment seem to contribute to subfertility. Several attempts have been made to restore fertility in adenomyosis patients, the oldest being gonadotrophin-releasing hormone agonists coupled to conservative surgery. Also, uterine artery embolization and MRI-assisted high-intensity focused ultrasound ablation have been tried with some degree of success.

Estrogen and progesterone receptor isoform distribution through the menstrual cycle in uteri with and without adenomyosis

OBJECTIVE

To test the hypothesis that the expression of the different isoforms of the estrogen receptor alpha (ER-α) and beta (ER-β) and the progesterone receptor A (PR-A) and B (PR-B) would be differentially modulated in uteri with adenomyosis compared with controls and that modulation would be related to the menstrual cycle.

DESIGN

Case control, blinded comparison.

SETTING

University department.

PATIENT(S)

54 premenopausal women with and 35 without uterine adenomyosis as the sole pathology.

INTERVENTION(S)

Multiple samples studied using immunohistochemistry for estrogen and progesterone receptors.

MAIN OUTCOME MEASURE(S)

Histomorphometric analysis of receptor expression.

RESULT(S)

The ER-α expression in the adenomyotic endometrium was different from that of the normal endometrium and the foci in the midsecretory phase of the cycle, but expression of ER-α in the inner and outer myometrium was not statistically significantly different. The ER-β expression was statistically significantly elevated in the adenomyotic functionalis gland during the proliferative phase and throughout the myometrium across the entire menstrual cycle. Expression of PR-A was similar to that of PR-B, with reduced expression in the basalis stroma, and inner and outer myometrium in the adenomyotic samples. The pattern of ER-β, PR-A, and PR-B expression was similar in the endometrial basalis and adenomyotic foci.

CONCLUSION(S)

These data suggest ER-β expression and the lack of PR expression are related to the development and/or progression of adenomyosis and might explain the poor response of adenomyosis-associated menstrual symptoms to progestational agents.

The enigmatic uterine junctional zone: the missing link between reproductive disorders and major obstetrical disorders?

While there is a growing realization that the origins of major obstetrical complications associated with defective deep placentation, such as pre-term labour, fetal growth restriction and pre-eclampsia, may lie in the very early pregnancy events, the underlying mechanisms are not understood. Impaired deep placentation is foremost a vascular pathology, characterized by a lack of endovascular trophoblast invasion and remodelling of a segment of the spiral arteries embedded within the inner myometrium of the uterus. Outside pregnancy, the inner myometrium represents a highly specialized, hormone-dependent structure, termed the junctional zone (JZ), which plays an integral part in the implantation process. The JZ changes with age and is disrupted in several reproductive disorders, such as endometriosis and adenomyosis, which in turn may account for the increased risk of adverse pregnancy outcome. Unlike the endometrium, the myometrial JZ is not readily accessible to biochemical or molecular studies, yet its structure and function can be assessed using imaging techniques, such as high-resolution ultrasound and magnetic resonance imaging. Thus, non-invasive assessment of the JZ prior to conception may turn out to be useful in identifying those women at risk of major obstetrical complications.

Adenomyosis: New Knowledge is Generating New Treatment Strategies

In the early days, all mucosal invasions of abdominal organs were considered to be one pathological condition of uncertain origin, termed adenomyoma. It was only in the 1920s that endometriosis and adenomyosis were clearly separated and it took approximately 80 years to put forward a new theory reunifying their pathogenesis. Today, identification of adenomyosis is carried out exclusively through vaginal ultrasonography and MRI. These techniques have made a careful evaluation of a distinct anatomical structure and the inner myometrial layers underlying the endometrium, termed the junctional zone, possible. Adenomyosis is characterized by a homogeneous thickening of this portion of the myometrium. When this hyperplasia is associated to an alteration of spiral arterioles' angiogenesis, then both adenomyosis and endometriosis may develop. Evidence is being accumulated that pre-eclampsia, fetal growth restriction and premature delivery may be linked, together representing a new, major obstetrical syndrome characterized by a modified uterine environment around the time of nidation. A dozen different medical or surgical techniques are utilized for the treatment of adenomyosis and novel approaches are being tested. These include use of inhibitors of angiogenesis that have been shown to cause reduced neo-angiogenesis, a significant modification of gene expression and a decrease in the percentage of active lesions. Encouraging results have also been obtained with the levonorgestrel-releasing intrauterine system.

Uterine adenomyosis: a need for uniform terminology and consensus classification

Modern imaging techniques allow non-invasive diagnosis of adenomyosis, a relatively common disorder characterized by the presence of heterotopic endometrial glands and stroma in the myometrium with hyperplasia of the adjacent smooth muscle. The study of adenomyosis is greatly hampered by a lack of clear terminology and the absence of a consensus classification of the lesions. Any classification of adenomyosis must begin with an evaluation of the myometrium underlying the endometrium, the so-called junctional zone, since homogeneous thickening of this zone has become the standard criterion for non-invasive diagnosis. Although transvaginal sonography is useful for the detection of adenomyosis, the technique is highly operator dependent. Magnetic resonance imaging provides superior soft tissue resolution and currently represents the most accurate technique for non-invasive diagnosis. Adenomyosis represents a spectrum of lesions, ranging from increased thickness of the junctional zone to overt adenomyosis and adenomyomas, which in turn can be subclassified. It is increasingly recognized that adenomyosis is often associated with pelvic endometriosis yet the contribution of myometrial lesions to clinical symptoms, such as infertility and pain, remains poorly understood. Moreover, recent studies indicate that adenomyosis is a progressive disease that changes in appearance during the reproductive years. A consensus classification of uterine adenomyosis is urgently required.

The uterine junctional zone

Magnetic resonance imaging has revealed that the endometrio-myometrial interface constitutes a distinct, hormone-dependent uterine compartment termed the junctional zone. In the non-pregnant uterus, highly specialized contraction waves originate exclusively from the junctional zone and participate in the regulation of diverse reproductive events, such as sperm transport, embryo implantation, and menstrual shedding. Conversely, growing evidence suggests that disruption of the normal endometrio-myometrial interface plays an integral role in diverse reproductive disorders. This chapter reviews our current understanding of the mechanisms that govern the cyclic changes in the uterine junctional zone and summarizes the evidence implicating the endometrio-myometrial interface in normal uterine physiology and pathological processes.

Dysmenorrhea: Evaluation with Cine-Mode-Display MR Imaging—Initial Experience

PURPOSE

To prospectively evaluate uterine contractility during menstruation and its relation to primary dysmenorrhea by using magnetic resonance (MR) imaging with cine mode display.

MATERIALS AND METHODS

The university ethics committee approved the study protocol, and all subjects gave written informed consent. Nineteen healthy women were examined during menstrual cycle days 1-3 by using a 1.5-T-magnet unit. Sixty serial half-Fourier rapid acquisition with relaxation enhancement MR images of the uterus were obtained every 3 seconds for 3 minutes and displayed in cine mode. MR images were analyzed in terms of thickness of the inner low-signal-intensity myometrial layer, presence of endometrial distortion, and uterine peristalsis detectability. Pain was assessed by using a four-point scale. For 56 MR imaging cases, the association between MR imaging findings and pain degree was examined with Spearman correlation and Mann-Whitney tests. MR imaging findings in the dysmenorrheic and eumenorrheic subject groups were compared by using Mann-Whitney and chi(2) tests. The area of the uterine myometrium in both groups was calculated for quantitative assessment of uterine contraction and was compared between the groups by using the Student t test.

RESULTS

MR imaging findings revealed marked changes during cycle days 1-3. Thickness of the inner low-signal-intensity myometrial layer and endometrial distortion were significantly associated with pain degree (P < .001), while uterine peristalsis was undetectable when pain was severe or moderate. The area of the uterine myometrium significantly decreased during cycle days 1-3 in the dysmenorrheic group, as compared with that in the eumenorrheic group (P = .010).

CONCLUSION

MR imaging features of the uterus on cycle days 1-3 correlated with pain degree. Cine-mode-display MR imaging is a potential tool for evaluating dysmenorrhea.

Uterine tissue development in healthy women during the normal menstrual cycle and investigations with magnetic resonance imaging

OBJECTIVE

High-resolution magnetic resonance imaging (MRI) was used to monitor both uterine endometrial and junctional zone morphometry during the normal menstrual cycle.

STUDY DESIGN

Twenty-four healthy, ovulating women were studied during a single menstrual cycle. Three scans were performed to prospectively coincide with the follicular, periovulatory, and luteal phases of the cycle.

RESULTS

MRI data showed a significant increase in endometrial and junctional zone volume, between the follicular and periovulatory phases, with a significant decrease in endometrial volume observed from the periovulatory to luteal phases. The regularity index, which is a novel subjective assessment of junctional zone structure, varied significantly and demonstrated a less regular junctional zone in the luteal phase.

CONCLUSION

This study has quantified the normal developmental changes of uterine tissue during the menstrual cycle with MRI. Junctional zone data from MRI may play a major role in future studies that investigate menstrual disorders, subfertility, and pathologic changes.

Defining endometrial growth during the menstrual cycle with three-dimensional ultrasound

OBJECTIVE

To define the changes in endometrial morphometry that occur during the normal menstrual cycle and to examine the discriminatory power of volumetric analysis over conventional two-dimensional measurements in quantifying the effect of compounding factors on endometrial growth.

DESIGN

The design was that of a longitudinal observational study. Subjects were seen on an alternate-day basis until ovulation and then every four days until the next menstrual period.

SETTING

A University teaching hospital.

POPULATION

Thirty women with regular cycles and acceptable "normal", menstrual patterns.

METHODS

Three-dimensional ultrasound data were acquired and subsequently analysed by a single observer.

MAIN OUTCOME MEASURES

Endometrial thickness and volume.

RESULTS

Both endometrial volume and thickness increased significantly during the follicular phase (P < 0.001), reaching a plateau around the time of ovulation and remaining relatively stable throughout the luteal phase. These changes in endometrial thickness and volume were highly correlated (R(2)= 0.767; P < 0.001). Parity was associated with a significantly greater endometrial volume than nulliparity (4.159 vs 2.234 cm(3); P < 0.05).

CONCLUSIONS

This study has defined the relative and absolute changes in endometrial growth, both in terms of thickness and volume, throughout the normal menstrual cycle. These data provide a reference for future three-dimensional studies investigating menstrual disorders, pathophysiological change and subfertility.

Uterine peristalsis shown on cine MR imaging using ultrafast sequence

PURPOSE

To demonstrate and evaluate uterine peristalsis on cine magnetic resonance imaging (MRI) using ultrafast imaging.

MATERIALS AND METHODS

Serial MR uterine images (300) were obtained from 15 normal volunteers over four menstrual phases using true fast imaging with steady-state precession (true FISP) technique over 117 seconds and videotaped. Three radiologists independently evaluated videotapes of 59 studies. Uterine peristalsis was defined as wavy movements of subendometrial myometrium or endometrium. Interobserver reliability was evaluated using a Kappa coefficient. Fifty-four studies obtained in appropriate phases were analyzed.

RESULTS

Cine MRI displayed uterine peristalsis in 30 of 59 studies; consensus reading showed direction in 23 studies. Reliability between the final consensus of the recognition of uterine peristalsis and those of the three readers was extremely concordant, with a Kappa coefficient of 0.908. Wave direction was cervico-fundal in follicular and periovulatory phases, with frequency of contraction waves being 1.2-2.3 per minute in positive studies.

CONCLUSION

Uterine peristalsis was demonstrated on cine MR using ultrafast MRI. Direction and frequency of peristaltic waves are closely related to menstrual cycle phases. Supplementary material for this article can be found on the JMRI website at http://www.interscience.wiley.com/jpages/1053-1807/suppmat/index.html.

Ultrasonographic evaluation of the endometrium in postmenopausal vaginal bleeding

Transvaginal ultrasound with SIS is a cost-minimizing screening tool for perimenopausal and postmenopausal women with vaginal bleeding. Its use decreases the need for invasive diagnostic procedures for women without abnormalities, and ultrasound increases the sensitivity of detecting abnormalities in women with pathologic conditions. Vaginal sonography is preferred over uniform biopsy of postmenopausal women with vaginal bleeding because it (1) is a less invasive procedure, (2) is generally painless, (3) has no complications, and (4) may be more sensitive for detecting carcinoma than blind biopsy. Transvaginal sonography is rarely nondiagnostic. Endometrial sampling is less successful in women with a thin endometrial stripe on ultrasound than in women with real endometrial pathologic condition. A limitation of ultrasound is that an abnormal finding is not specific: ultrasound cannot always reliably distinguish between benign proliferation, hyperplasia, polyps, and cancer. Although ultrasound may not be able to distinguish between hyperplasia and malignancy, the next step in the clinical treatment requires tissue sampling. Because of the risk of progression of complex hyperplasia to carcinoma, patients with this finding may benefit from hormonal suppression, dilatation and curettage, endometrial ablation, or hysterectomy, depending on the clinical scenario. The inability to distinguish these two entities based on ultrasound alone should not be seen as a limitation because tissue sampling is required in either case. Occasionally (in 5% to 10% of cases), a woman's endometrium cannot be identified on ultrasound, and these women also need further evaluation. Ultrasonography also may be used as a first-line investigation in other populations with abnormal uterine bleeding. In a multicenter, randomized, controlled trial of 400 women with abnormal uterine bleeding, the investigators found that transvaginal sonography combined with Pipelle endometrial biopsy and outpatient hysteroscopy was as effective as inpatient hysteroscopy and curettage. The subject, included women older than 35 years with PMB, menorrhagia, intermenstrual bleeding, postcoital bleeding, or irregular menses. Transvaginal sonography may be a cost-effective. sensitive, and well-tolerated method to evaluate most women with abnormal bleeding in combination with physical examination and endometrial biopsy and hysteroscopy us indicated. Hysteroscopy is likely to become the new gold standard in the future because of its ability to visualize directly the endometrium and perform directed biopsies as indicated. As office-based hysteroscopy becomes more practical and widespread, the technique may become more cost effective. An evaluation plan using transvaginal sonography as the initial screening evaluation followed by endometrial biopsy or, more likely, hysteroscopy is likely to become the standard of care (Fig. 12). It remains unproven whether certain patients at higher risk for carcinoma should proceed directly to invasive evaluation. Women on tamoxifen with persistent recurrent bleeding, women with significant risk factors for carcinoma, and women with life-threatening hemorrhage comprise this group. Further studies are still necessary to evaluate high-risk patients and determine whether ultrasound or biopsy is really the most cost-effective initial test.

The myometrial junctional zone spiral arteries in normal and abnormal pregnancies: a review of the literature

Deep placentation in the human requires physiologic transformation of the spiral arteries into uteroplacental vessels. This process involves the inner myometrial segment (junctional zone) of the spiral arteries and is effected by trophoblast invasion of the vessel wall, resulting in complete loss of the arterial structure and deposition of fibrinoid and fibrous tissues. Absent or inadequate physiologic changes in the junctional zone spiral arteries limits placental blood flow in pregnancies complicated by preeclampsia and fetal growth restriction. The cause of defective deep placentation is still unknown, although it is often attributed to impaired trophoblast function and migration. However, trophoblast invasion is preceded by decidual remodeling of maternal tissues, a process that is initiated in the endometrium but extends into the junctional zone. This review examines the mechanisms that control decidualization and subsequent trophoblast invasion in normal and abnormal pregnancies. The possibility that disruption of the decidual process in the secretory phase of the menstrual cycle triggers a cascade of events resulting in failed deep placentation is explored.

Changes in myometrial and junctional zone thickness and signal intensity: demonstration with kinematic T2-weighted MR imaging

PURPOSE

To demonstrate uterine contractions by evaluating changes during time in the thickness of the myometrium and junctional zone and in signal intensity of the uterus with T2-weighted fast magnetic resonance (MR) images in a kinematic fashion.

MATERIALS AND METHODS

Sagittal MR imaging was performed with T2-weighted fast spin-echo (FSE) and multiphase-multisection single-shot FSE (SSFSE) in 60 premenopausal patients during free breathing. SSFSE MR images were evaluated with cine display. The pattern of uterine contractions and changes in signal intensities of the uterine structures were evaluated. Thickness of both myometrium and junctional zone, and their signal intensities, were measured during 15 phases of SSFSE and FSE MR imaging.

RESULTS

Slow-massive (mean, 55%), middle-cycle (mean, 80%), and fine (mean, 93%) contractions were observed. Shape of junctional zones dynamically changed during time, showing focal (mean, 58%) and diffuse (mean, 82%) thickening and wavelike motions (mean, 88%). Ratio of thickness of the myometrium to junctional zone with FSE MR imaging was not significantly different from the mean ratio during 15 phases of SSFSE MR imaging, although maximum percentage of change of the ratio during 15 phases was 42.5%-56.8%. The signal intensities of the myometrium (97%) and junctional zone (75%) changed during time.

CONCLUSION

Kinematic T2-weighted SSFSE MR images demonstrate uterine contractions related to dynamic changes in thickness and signal intensities of the myometrium and junctional zone, and these findings might affect the diagnosis of uterine disease.

Uterine adenomyosis: current concepts in imaging

This article reviews the clinical findings, histopathological features, and treatment options of uterine adenomyosis and relates them to the role of the radiologist in evaluating patients with this disease. Knowledge of the histopathology of this disease is essential to understanding the range of imaging findings encountered in patients with uterine adenomyosis. In addition, the imaging features and accuracy of noninvasive diagnostic modalities that have proven useful in diagnosing adenomyosis will be discussed. Correctly diagnosing the presence of adenomyosis, and determining its extent, is crucial in planning the appropriate type of therapy.

Relaxation time changes of the uterus during the menstrual cycle: correlation with hormonal status

Six women volunteers underwent pelvic MR imaging at 0.02 T four times during their menstrual cycle. The T1 and T2 relaxation times of the myometrium and endometrium were measured and correlated with the serum estradiol and progesterone levels. The magnitude of the relaxation times were highly individual but the pattern of their variation during the menstrual cycle was similar. The relaxation times were shortest at the beginning and end of the cycle. The most rapid increase occurred during the proliferative phase, followed by little or no increase through to the middle of the secretory phase. The T1 and T2 times of the endometrium correlated directly with the serum estradiol levels during the entire menstrual cycle (r = 0.5, P = 0.02) and the T2 times of the endometrium with the serum progesterone levels during the secretory phase (r = 0.6, P = 0.05). The correlation between the relaxation times of the myometrium and the serum hormonal levels was poor. The results indicate that the relaxation times of the myometrium and endometrium vary during the menstrual cycle reflecting the serum hormonal status. MR imaging of the uterus with relaxation time measurements may be clinically useful to examine the menstrual cycle and its pathology.

Sonohysterography for endometrial abnormalities: preliminary results

In examinations where the etiology of an abnormal endometrial sonographic image is not clear, saline infusion through a fine flexible catheter during transvaginal sonography provides visual contrast and uterine expansion. In 39 women, polyps, myomata, synechiae, endometrial hyperplasia, and cancer were correctly described as verified at surgery. Hyperplasia and neoplasia are not distinguishable, but the approach for biopsy and therapy is established by this simple and well-tolerated technique, which is here called sonohysterography.

Quantitative MRI of the prostate and uterus in monkeys

Quantitative MRI has been carried out in the prostate, seminal vesicles, uterus, and ovaries in the pig-tailed monkey, Macaca nemestrina. T2-weighted, fat-suppressed, multislice experiments were performed at 2.35 T. Eight males, 14 ovariectomized females, and 20 intact females were studied. In the prostate, the caudal and cranial lobe were readily distinguished since the latter had a longer T2 value. For all tissues and organs, interanimal variations were large (up to 12-fold variation in volume), but reproducibility was excellent in the prostate and in the ovariectomized monkey uterus with coefficients of variation (CV) of 3 and 5%, respectively. In the intact monkey uterus, cycle-cycle reproducibility was good with CVs of 6-10% in the myometrium and 14-18% in the endometrium. In the follicular phase, endometrial growth (+3.8% day-1, P < 0.001) was accompanied by myometrial shrinkage (-1.6% day-1, P < 0.001), while in the luteal phase, growth was seen in both tissues (+4.3% day-1, P < 0.001 and +1.4% day-1, P < 0.001, respectively). The great value of these MRI techniques in obtaining data in pharmacological efficacy studies of endocrine drugs, and in limiting the number of animals used, is discussed.

Evaluation of the stimulated menstrual cycle by magnetic resonance imaging

Changes in uterine zonal anatomy in six women during a cycle of treatment with clomiphene citrate is studied by magnetic resonance imaging. There was a rapid rate of increase in endometrial thickness during the periovulatory period that was similar to the pattern seen in a prior study of women with normal (nonstimulated) cycles. Junctional zone thickness did not parallel the endometrial pattern and differed from the response seen in nonstimulated cycles. Results of large scale studies may help to further understand the effects of these medications.

Contractions of the inner third of the myometrium

Forty-six consecutive endovaginal ultrasound examinations were screened for the presence of myometrial contractions. The study group contained pregnant women up to 10 weeks' menstrual age, nonpregnant, and postmenopausal women. Rhythmic myometrial contractions of the inner myometrial third not previously reported were seen in 35 studies in pregnant, nonpregnant, and postmenopausal women. The contractions involved the inner third of the myometrium in all but two cases. In these two cases, all three muscular layers were involved. The majority of women showed retrograde contractions, with the contraction wave moving from the cervix to the fundus. In menstruating women and one case of abortion, the contractions were antegrade. It is our speculation that these retrograde contractions of the inner myometrial third may be important in sperm transport and for the conservation of early pregnancies within the uterine cavity.

Manipulating the follicular phase in IVF cycles: a comparison of two hMG stimulation protocols

The results of two human menopausal gonadotropin (hMG) protocols of ovulation induction for in vitro fertilization (IVF) were compared. With the first protocol, 28 women (group 1) were treated with an hMG dosage which was increased stepwise. With the second, 30 women (group 2) were treated with a high dose of hMG for 2 days, then given a constant daily dose. The two groups were compared with regard to ovarian response, luteal phase and laboratory and clinical outcomes of IVF. They were comparable as regards the total number of hMG doses required, the number of large follicles (mean diameter greater than 15 mm) on day 0 (day of human chorionic gonadotropin (hCG) administration), serum estrogen (E2) and progesterone (P) levels throughout the cycle and IVF laboratory and clinical outcomes. They differed significantly (p less than 0.01) only in the number of secondary smaller follicles (mean diameter less than 15 mm) observed on day 0 (3.7 +/- 0.4 for group 1 and 5.3 +/- 0.4 for group 2). Manipulating the hMG dosage during the early-mid follicular phase does not affect follicular synchrony, the number of oocytes harvested and the number of embryos achieved.