Uterine peristalsis shown on cine MR imaging using ultrafast sequence

Application of PET/MRI in Gynecologic Malignancies

The diagnosis, treatment, and management of gynecologic malignancies benefit from both positron emission tomography/computed tomography (PET/CT) and MRI. PET/CT provides important information on the local extent of disease as well as diffuse metastatic involvement. MRI offers soft tissue delineation and loco-regional disease involvement. The combination of these two technologies is key in diagnosis, treatment planning, and evaluating treatment response in gynecological malignancies. This review aims to assess the performance of PET/MRI in gynecologic cancer patients and outlines the technical challenges and clinical advantages of PET/MR systems when specifically applied to gynecologic malignancies.

Magnetic Resonance Imaging-guided Focused Ultrasound Surgery in a Swine Adenomyosis Model

RATIONALE AND OBJECTIVES

The purpose of this study was to explore the feasibility of magnetic resonance imaging-guided focused ultrasound surgery (MRgFUS) for the treatment of an adenomyosis model of Bama pigs and the changes in the level of oxytocin receptor (OTR), vascular endothelial growth factor (VEGF), and cyclooxygenase-2 (COX-2) in the myometrium tissues of Bama pigs after MRgFUS.

MATERIALS AND METHODS

Three Bama pig models of adenomyosis were established by autologous endometrial implantation and evaluated by magnetic resonance imaging, computed tomography, and hematoxylin-eosin (H&E) staining. After the successful construction of the model, the pigs underwent MRgFUS. Before the modeling surgery, three months after the modeling, and two months after ablation, the myometrium tissues were clipped, then embedded and H&E stained for immunohistochemical examination. The average optical density of OTR, VEGF, and COX-2 were semi-quantitatively analyzed.

RESULTS

The adenomyosis models were established in all Bama pigs and confirmed by magnetic resonance imaging, computed tomography and H&E staining. Magnetic resonance imaging and computed tomography examination showed that the uterine wall at the modeling site was significantly thickened with uneven enhancement after contrast injection. All Bama pigs with adenomyosis lesions underwent MRgFUS without complications. The expression level of OTR and COX-2 in the myometrium increased three months after modeling surgery and decreased two months after MRgFUS. The expression level of VEGF decreased two months after MRgFUS.

CONCLUSION

Autologous endometrial implantation is effective in establishing the adenomyosis model of Bama pigs. It is feasible to treat adenomyosis in the Bama pig model with MRgFUS. The levels of OTR, COX-2 and VEGF in the local myometrium decreased after MRgFUS, which may be associated with symptom relief after treatment.

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.

Cyclic changes in T2* relaxometry of human uterus during the menstrual cycle using BOLD MR imaging

PURPOSE

To evaluate dynamic changes of T2* values within the endometrium, junctional zone and myometrium during the menstrual cycle using blood oxygen level-dependent (BOLD) magnetic resonance imaging.

METHOD

Volunteers underwent MRI scans on menstrual phase, ovulatory phase and luteal phase, including T2-weighted imaging and BOLD MR imaging. Multi-gradient-recalled echo (MGRE) sequence was used to obtain BOLD MR images. T2* values of different uterine layers, including endometrium, junctional zone and myometrium, on sagittal images were analyzed quantitatively.

RESULTS

Twenty-four subjects calculated T2* values successfully. The T2* values of each zonal structure during menstruation were significantly lower than those during ovulatory phase (P < 0.05) and luteal phase (P < 0.001). The T2* value of junctional zone was significantly lower than that of the myometrium over all three menstrual phases (P = 0.000, menstrual; P = 0.000, ovulatory; P = 0.001, luteal). The mean T2* value in endometrium during the ovulatory phase was the highest of the uterine zones over menstrual cycle. During menstrual phase, there was no statistical difference between endometrium and junctional zone (P > 0.05). Conversely, the comparison of the T2* values between endometrium and myometrium, junctional zone and myometrium both showed significant difference (P = 0.000). The mean T2* values within endometrium during ovulatory phase and luteal phase were significantly higher than those within junctional zone and myometrium (P < 0.05).

CONCLUSIONS

Cyclic changes of T2* values in each zonal structure of the uterus were revealed during the menstrual cycle by means of BOLD technique, which may be potentially beneficial in investigating dysmenorrhea, guiding assisted reproductive technologies and monitoring hypoxia in gynecological tumors.

A Uterine Motion Classification in MRI Data for Female Infertility

AIMS

The purpose of this study was to classify complicated uterine movements obtained by MRI scanner and investigate the relationship between uterine peristalsis and female infertility.

METHODS

Uterine movements are classified into six fundamental movements by their motility form and directions. Computer simulation of the uterine movements is performed.

RESULTS

Comparison results between the real MRI images and the simulated images showed that any five in our dataset uterine movement was successfully reproduced by a combination of these six fundamental movements. The point and surface vibration model appropriately mimicked the movements with the propagation velocity of 0.68 [mm/sec].

CONCLUSION

By analyzing six fundamental movements using data from 26 MRI scans, it was found that two fundamental movements were identified as candidate factors for female infertility.

Voxelated three-dimensional miniature magnetic soft machines via multimaterial heterogeneous assembly

Small-scale soft-bodied machines that respond to externally applied magnetic field have attracted wide research interest because of their unique capabilities and promising potential in a variety of fields, especially for biomedical applications. When the size of such machines approach the sub-millimeter scale, their designs and functionalities are severely constrained by the available fabrication methods, which only work with limited materials, geometries, and magnetization profiles. To free such constraints, here, we propose a bottom-up assembly-based 3D microfabrication approach to create complex 3D miniature wireless magnetic soft machines at the milli- and sub-millimeter scale with arbitrary multimaterial compositions, arbitrary 3D geometries, and arbitrary programmable 3D magnetization profiles at high spatial resolution. This approach helps us concurrently realize diverse characteristics on the machines, including programmable shape morphing, negative Poisson's ratio, complex stiffness distribution, directional joint bending, and remagnetization for shape reconfiguration. It enlarges the design space and enables biomedical device-related functionalities that are previously difficult to achieve, including peristaltic pumping of biological fluids and transport of solid objects, active targeted cargo transport and delivery, liquid biopsy, and reversible surface anchoring in tortuous tubular environments withstanding fluid flows, all at the sub-millimeter scale. This work improves the achievable complexity of 3D magnetic soft machines and boosts their future capabilities for applications in robotics and biomedical engineering.

Markers of human endometrial hypoxia can be detected in vivo and ex vivo during physiological menstruation

STUDY QUESTION

Can markers of human endometrial hypoxia be detected at menstruation in vivo?

SUMMARY ANSWER

Our in vivo data support the presence of hypoxia in menstrual endometrium of women during physiological menstruation.

WHAT IS KNOWN ALREADY

Current evidence from animal models and human in vitro studies suggests endometrial hypoxia is present at menstruation and drives endometrial repair post menses. However, detection of human endometrial hypoxia in vivo remains elusive.

STUDY DESIGN, SIZE, DURATION

We performed a prospective case study of 16 women with normal menstrual bleeding.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Reproductively aged female participants with a regular menstrual cycle underwent objective measurement of their menstrual blood loss using the alkaline haematin method to confirm a loss of <80 ml per cycle. Exclusion criteria were exogenous hormone use, an intrauterine device, endometriosis or fibroids >3 cm. Participants attended for two MRI scans; during days 1-3 of menstruation and the early/mid-secretory phase of their cycle. The MRI protocol included dynamic contrast-enhanced MRI and T2* quantification. At each visit, an endometrial sample was also collected and hypoxia-regulated repair factor mRNA levels (ADM, VEGFA, CXCR4) were quantified by RT-qPCR.

MAIN RESULTS AND THE ROLE OF CHANCE

Women had reduced T2* during menstrual scans versus non-menstrual scans (P = 0.005), consistent with menstrual hypoxia. Plasma flow (Fp) was increased at menstruation compared to the non-menstrual phase (P = 0.0005). Laboratory findings revealed increased ADM, VEGF-A and CXCR4 at menstruation on examination of paired endometrial biopsies from the menstrual and non-menstrual phase (P = 0.008; P = 0.03; P = 0.009). There was a significant correlation between T2* and these ex vivo hypoxic markers (P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

This study examined the in vivo detection of endometrial hypoxic markers at specific timepoints in the menstrual cycle in women with a menstrual blood loss <80 ml/cycle and without significant uterine structural abnormalities. Further research is required to determine the presence of endometrial hypoxia in those experiencing abnormal uterine bleeding with and without fibroids/adenomyosis.

WIDER IMPLICATIONS OF THE FINDINGS

Heavy menstrual bleeding (HMB) is a common, debilitating condition. Understanding menstrual physiology may improve therapeutics. To our knowledge, this is the first in vivo data supporting the presence of menstrual hypoxia in the endometrium of women with normal menstrual bleeding. If aberrant in those with HMB, these non-invasive tests may aid diagnosis and facilitate personalized treatments for HMB.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by Wellbeing of Women grant RG1820, Wellcome Trust Fellowship 209589/Z/17/Z and undertaken in the MRC Centre for Reproductive Health, funded by grants G1002033 and MR/N022556/1. H.O.D.C. has clinical research support for laboratory consumables and staff from Bayer AG and provides consultancy advice (but with no personal remuneration) for Bayer AG, PregLem SA, Gedeon Richter, Vifor Pharma UK Ltd, AbbVie Inc; Myovant Sciences GmbH. H.O.D.C. receives royalties from UpToDate for articles on abnormal uterine bleeding.

TRIAL REGISTRATION NUMBER

N/A.

Impairment of Uterine Contractility Is Associated with Unexplained Infertility

The uterine junctional zone represents the juncture between endometrium and myometrium. The junctional zone is hormonally dependent and displays continuous peristaltic activity throughout the menstrual cycle in the nonpregnant state which is concerned with sperm transport and embryo implantation. Peristalsis may be observed using various invasive and noninvasive modalities, of which ultrasound is the most readily applied in the clinical setting. Women with pelvic pathology display alterations in uterine peristalsis which may contribute to infertility. Characterization of peristalsis in infertility subgroups, the development of a subjective peristalsis tool, and the application of potential therapeutics to an assisted reproductive treatment setting are the subject of ongoing investigation. Meta-analysis indicates a potential role for oxytocin antagonist in the improvement of fertility treatments.

Cine magnetic resonance urography for postoperative evaluation of reconstructive urinary tract after ileal ureter substitution: initial experience

AIM

To report the initial experiences with functional cine magnetic resonance urography (cine MRU) and assess its usefulness as a novel postoperative evaluation method of ileal ureter substitution.

MATERIALS AND METHODS

The medical records of 17 patients from who underwent cine MRU during June 2010 to December 2019 during their follow-up after ileal ureter substitution were collected. The cine MRU videos of reconstructive urinary tract were observed, and the luminal diameter, contraction ratio, peristaltic waves, and ureteral jets were measured.

RESULTS

Seventeen patients underwent cine MRU after ileal ureter substitution during their follow-up. Based on their cine MRU videos assessing the morphology and the peristaltic motility of the reconstructive urinary tract, there was resolution of preoperative hydronephrosis, which matched their ameliorative renal function. Clearly, peristaltic motility of the ileal graft was observed in 14 patients with obvious peristaltic waves and ureteral jets.

CONCLUSION

This study is the first to assess the clinical utility of functional cine MRU during the patient follow-up after ileal ureter substitution. Cine MRU is a radiation-free, non-invasive imaging method that can clearly show the morphology and the peristaltic motility of the ileal graft. Therefore, cine MRU, as a novel technique, will be extremely useful in the postoperative evaluation of patients after ileal ureter substitution.

Impact of uterine contractility on quality of life of women undergoing uterine fibroid embolization

Background

Although changes in uterine contractility pattern after uterine fibroid embolization (UFE) has already been assessed by cine magnetic resonance imaging (MRI), their impact on quality of life outcomes has not been evaluated. The purpose of this study was to evaluate the impact of uterine contractility on the quality of life of women undergoing UFE measured by the Uterine Fibroid Symptom and Quality of Life questionnaire (UFS-QOL).

Results

A total of 26 patients were included. MRI scans were acquired 30–7 days before and 6 months after UFE for all patients. The UFS-QOL was applied in person on first MRI exam day and 1 year after UFE and the outcomes were analyzed according to the groups of evolution pattern of uterine contractility: Group A: Unchanged Uterine Contractility Pattern, 38%; Group B: Favorable Modified Uterine Contractility Pattern, 50%; and Group C: Loss of Uterine Contractility, 11%. All UFE patients presented a reduction in the mean score for symptoms and increase in mean scores on quality of life. All patients in this cohort presented a reduction in mean symptom score and increase in the mean score of quality of life subscales. Group A had more relevant complaints regarding their sense of self-confidence; Group B presented worse sexual function scores before UFE, which improved after UFE compared to Group A.

Conclusions

Significant improvement in symptoms, quality of life, and uterine contractility was observed after UFE in women of reproductive age with symptomatic fibroids. Functional uterine contractility seems to have a positive impact on quality of life and sexual function in this population.

Level of evidence

Level 3, Non-randomized controlled cohort/follow-up study.

Study of uterine kinetics in nonpregnant women using cine-mode magnetic resonance imaging

PURPOSE

To evaluate the uterine kinetics in each phase of the menstrual cycle when observed in detail using cine-mode magnetic resonance imaging (MRI) of sagittal and transverse plane images.

METHODS

Seven volunteers with a history of multiple natural pregnancies and deliveries were enrolled from January 2017 to May 2017. The kinetic parameters (depth, frequency, and direction) of uterine muscle contractions were evaluated in cine-mode MRI.

RESULTS

Strong contractions from the uterine cornua to cervix were detected during menstruation. In the late follicular phase, the frequency of opposing contractions from the cervix and uterine cornua increased. Immediately before ovulation, contractions from the cervix reached the uterine fundus. After ovulation, opposing contractions returned. These contractions gradually decreased in the mid-luteal phase, while fine contractions from the cervix to the middle of the uterine body were frequently observed until 7 days after ovulation. Few contractions were observed in the implantation phase.

CONCLUSIONS

Our data suggest that the uterine kinetics change in each phase of the menstrual cycle in accordance with the purpose of the uterus in each phase. Further, cine-mode MRI studies of each phase are needed to assess the relationships between uterine kinetics and infertility.

Diffusion Tensor Imaging (DTI) of the Cesarean-Scarred Uterus in vivo at 3T: Comparison Study of DTI Parameters Between Nonpregnant and Pregnant Cases

BACKGROUND

Fiber architecture of the human uterus can be depicted in vivo using 3T MR-DTI (diffusion tensor imaging).

PURPOSE

To investigate the differences in fibrous structure and DTI-related parameters between nonpregnant and pregnant cases in vivo.

STUDY TYPE

Prospective case-control study.

SUBJECTS

Thirty-one subjects were divided into two groups; 18 nonpregnant volunteers with previous cesarean deliveries (Group 1) and 13 patients in early pregnancy also with previous cesarean section (Group 2).

FIELD STRENGTH/SEQUENCE

3T Ssh-EPI (single-shot echo planar imaging) fast sequence with b values of 0 and 600 s/mm² along 30 directions.

ASSESSMENT

Fiber density, fiber length, apparent diffusion coefficient (ADC) value, and the fractional anisotropy (FA) value measured in the mid-sagittal plane of the uterus were obtained from the outer myometrium (OM), junctional zone (JZ), and the cesarean section scar (CSS). Fiber architecture in vivo was depicted by 3D diffusion tensor tractography (DTT).

STATISTICAL TESTS

A t-test of independent sample or Wilcoxon rank sum test were used for comparison.

RESULTS

Pregnant scarred-uterus (Group 2) showed a decrease in fiber density, FA value, and an increase in fiber length, ADC value than the nonpregnant scarred-uterus (Group 1) on OM, JZ, and CSS. Among the above parameters between the two groups, for OM, significant differences were found in fiber density (P < 0.001), length (P = 0.0306), and ADC (P = 0.0039). For JZ, significant differences were found in fiber density (P = 0.0093), FA (P = 0.0002), and ADC (P < 0.001). The scar's fiber density (P = 0.0794), length (P = 0.6167), FA (P = 0.6305), and ADC value (P = 0.1865) showed no statistically significant difference during early pregnancy.

DATA CONCLUSION

Our results indicate considerable diffusional changes in uterine fiber architecture during pregnancy. The microenvironment of scar tissue appears to change little during early pregnancy.

LEVEL OF EVIDENCE

2 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:124-130.

Uterine Peristalsis Before and After Ultrasound-Guided High-Intensify Focused Ultrasound (USgHIFU) Treatment for Symptomatic Uterine Fibroids

Background

This study investigated uterine peristalsis before and after ultrasound-guided high-intensify focused ultrasound (USgHIFU) treatment for symptomatic uterine fibroids by cine magnetic resonance imaging (cine MRI).

Material/Methods

A total of 30 patients with symptomatic uterine fibroids were treated by USgHIFU, who were subjected to cine MRI before and after USgHIFU treatment in the periovulatory phase. The images were analyzed for the existence, direction, and frequency of uterine peristalsis. The effects of uterine volume, the largest fibroid volume and location, and the fibroid number were examined before and after USgHIFU treatment.

Results

The incidence of uterine peristalsis was significantly increased after USgHIFU treatment. The main direction of uterine peristalsis before and after USgHIFU was cervix-to-fundus. In 12 cases, uterine peristalsis newly emerged after USgHIFU, and the largest fibroid volumes in these 12 cases were significantly smaller than in the remaining 18 cases before and after USgHIFU. The reduction rates of the largest fibroid volume in the 12 cases were significantly higher than in the remaining 18 cases. The largest fibroids were mainly located in the intramural area before and after USgHIFU.

Conclusions

USgHIFU treatment may contribute to the recovery of uterine peristalsis in patients with symptomatic fibroids, as detected by cine MRI. Uterine peristalsis recovery was related to the largest fibroid volume, especially for intramural fibroids.

Evaluation of Uterine Contractility by Magnetic Resonance Imaging in Women Undergoing Embolization of Uterine Fibroids

PURPOSE

To assess uterine contractility using ultrafast magnetic resonance imaging (cine MRI) before and after uterine fibroid embolization (UFE).

MATERIALS AND METHODS

This is a prospective study of uterine contractility in 26 patients (age 30-41 years) undergoing UFE for symptomatic uterine fibroids. Cine MRI was performed before and 6 months after UFE. Two radiologists evaluated uterine contractility and classified it as absent, ordered, or disordered. Patients were then grouped into three distinct patterns of progression: unchanged contractility (group A), modified contractility (B), and loss of contractility (C). These findings were then confronted with factors that might have interfered with uterine contractility pattern (uterine volume, location of dominant fibroid, fibroid/myometrium index, and fibroid necrosis pattern).

RESULTS

Of the 26 patients, 8 (30.7%) had no contractility before the procedure, while 18 (69.2%) exhibited some form of contractility (11 [61%] ordered, 7 [39%] disordered). All 8 patients who had no contractility at baseline exhibited contractility after UFE (5 ordered, 3 disordered). Of the 11 who had ordered contractility at baseline, 9 remained ordered and 2 lost contractility after UFE. Of the 7 with disordered contractility at baseline, 1 remained disordered, 5 progressed to ordered contractility, and 1 lost contractility. Overall, 10 patients (38%) had no change in contractility after UFE (group A), 13 (50%) had a positive change (group B), and 3 (11%) lost contractility (group C). The potential interference factors assessed had no statistically significant effect in any group.

CONCLUSION

In women of reproductive age with symptomatic fibroids, uterine contractility improved significantly after UFE.

LEVEL OF EVIDENCE

Level 3-non-randomized controlled cohort/follow-up study.

Biomechanics of the human uterus

The appropriate biomechanical function of the uterus is required for the execution of human reproduction. These functions range from aiding the transport of the embryo to the implantation site, to remodeling its tissue walls to host the placenta, to protecting the fetus during gestation, to contracting forcefully for a safe parturition and postpartum, to remodeling back to its nonpregnant condition to renew the cycle of menstruation. To serve these remarkably diverse functions, the uterus is optimally geared with evolving and contractile muscle and tissue layers that are cued by chemical, hormonal, electrical, and mechanical signals. The relationship between these highly active biological signaling mechanisms and uterine biomechanical function is not completely understood for normal reproductive processes and pathological conditions such as adenomyosis, endometriosis, infertility and preterm labor. Animal studies have illuminated the rich structural function of the uterus, particularly in pregnancy. In humans, medical imaging techniques in ultrasound and magnetic resonance have been combined with computational engineering techniques to characterize the uterus in vivo, and advanced experimental techniques have explored uterine function using ex vivo tissue samples. The collective evidence presented in this review gives an overall perspective on uterine biomechanics related to both its nonpregnant and pregnant function, highlighting open research topics in the field. Additionally, uterine disease and infertility are discussed in the context of tissue injury and repair processes and the role of computational modeling in uncovering etiologies of disease. WIREs Syst Biol Med 2017, 9:e1388. doi: 10.1002/wsbm.1388 For further resources related to this article, please visit the WIREs website.

Uterine peristalsis and junctional zone: correlation with age and postmenopausal status

Background Although age-related change of junctional zone (JZ) of the uterus has been known, there has been no previous systematic study of age-related changes of uterine peristalsis that is observed as the wave conduction of the thickest or darkest area within the JZ. Purpose To examine the age-related changes of uterine peristalsis in pre and postmenopausal women using cine magnetic resonance imaging (MRI), and to determine the correlation between peristalsis and JZ on T2-weighted (T2W) imaging. Material and Methods Cine MRI analysis was performed in 64 premenopausal volunteers and in 43 postmenopausal women. The peristaltic frequency, JZ detectability, and JZ thickness were evaluated and compared between the two groups. In the premenopausal group, the correlations between age and each item was examined. In the postmenopausal group, the number of years after menopause was used instead of age. The correlation between peristaltic frequency and JZ detectability or thickness was also analyzed. Results Peristaltic frequency and JZ detectability significantly differed between the two groups, while JZ thickness did not. Peristaltic frequency did not vary significantly with age before menopause and no peristalsis was observed after menopause. JZ detectability did not change significantly with age or number of years after menopause, while JZ thickness significantly increased with age before menopause, but did not vary after menopause. A significant moderate correlation was observed between JZ detectability and peristaltic frequency, but not between JZ thickness and peristaltic frequency. Conclusion Uterine peristalsis frequency did not change significantly according to age, but observed peristalsis on MRI significantly decreased after menopause.

Optimized approach to cine MRI of uterine peristalsis

PURPOSE

To determine the optimal slice thickness, playback rate, and scan time for uterine peristalsis with 3.0T magnetic resonance imaging (MRI).

MATERIALS AND METHODS

In all, 23 young female volunteers underwent a 3.0T MRI scan with different slice thicknesses of 3 mm (Cine_3mm ), 5 mm (Cine_5mm ), and 7 mm (Cine_7mm ) for 6 minutes. Subjective image quality score, signal-to-noise ratios (SNRs), and contrast-to-noise ratios (CNRs) of those MR images were evaluated by two radiologists independently. The number, intensity, and direction of uterine peristalsis with different thickness were compared at various playback rates. Also, the peristalsis frequency was counted and compared in different acquisition durations (1-6 minutes).

RESULTS

The subjective image quality score, peristalsis number, and intensity were significantly higher in Cine_7mm and Cine_5mm than Cine_3mm (P < 0.05), while the SNRs and CNRs of Cine_7mm were significantly higher than Cine_3mm (P < 0.05). Peristalsis numbers did not differ significantly at different playback rates with the same slice thickness (P = 0.548-0.962). However, peristalsis intensity at 12×, and 15× was significantly greater than that at 8× the actual speed for Cine_7mm and Cine_5mm (P < 0.05). The peristalsis frequency at 3, 4, 5, 6 minutes was significantly higher than that at 1 minute and 2 minutes (P < 0.05).

CONCLUSION

We recommend a slice thickness of 5 mm or 7 mm and a scan time of 3 minutes for uterine peristalsis with 3.0T MRI, and a playback rate of 12× or 15× the actual speed for peristalsis observation. J. Magn. Reson. Imaging 2016;44:1397-1404.

Uterine anatomy and function on cine magnetic resonance imaging

The female reproductive organ undergoes dynamic morphological changes under the influence of hormonal stimuli, and particularly those mediated by estrogen and progesterone. The uterus changes both its morphological appearance and its functional movements in function of these influences. Functionally, the uterus is known to exert two kinds of inherent contractility: sustained uterine contractions and uterine peristalsis. The former is focal and consists of the sporadic bulging of the myometrium, while the latter is rhythmic and manifests itself as the subtle stripping movement in the subendometrial myometrium. The mechanisms underlying these uterine movements, their relationship and their correlation to age, pharmaceutical administration, and a variety of gynecologic and obstetrical problems remain under discussion. Cine MR imaging may offer the potential to directly observe the changes undergone by the uterus in relation to important functions such as fertility and menstrual problems.

[An Examination for Uterine Dynamic Study with Phase-sensitive Inversion-recovery]

The depth of myometrial invasion in patients with endometrial carcinoma is recognized as an important factor that closely correlates with prognosis. Preoperative assessment of myometrial invasion is essential for planning surgery. To enhance the contrast between myometrium and endometrium including myometrial invasion with endometrial carcinoma, we optimized the sequence parameter with phase-sensitive inversion-recovery (PSIR) in gadolinium dynamic study of uterine corpus. On a 1.5-T magnetic resonance imaging (MRI), images were acquired by three-dimensional (3D) T1 -turbo field echo (TFE) with PSIR sequence and gadolinium-diethylenetriamine pentaacetic acid( Gd-DTPA) diluted phantom (0-5 mmol/L) and myometrium model (manganese chloride tetrahydrate+agar). We calculated the null point and the contrast-to-noise ratio (CNR) at multiple TFE inversion delay times, 200 ms-maximum in each combination; flip angles (FAs), 5-35 degrees; TFE factor, 20-40; and shot interval (SI), 500-1000 ms. We assumed that dynamic scanning time was 30 seconds when the sensitivity encoding factor was 2, namely, in this study, the scanning time was 1 minute with no sensitivity encoding. In addition, we compared CNR between optimized PSIR sequence ande-Thrive. We recognized a successful CNR of the 3D PSIR parameter was TFE inversion delay times, 335 ms; FA, 25 degrees; TFE factor, 20; and SI, 500 ms. In each gadolinium-DTPA diluted phantom, the average CNR of the optimized PSIR sequence was approximately 1.7 times (maximum: 3 times) higher than e-Thrive. Optimizing sequence parameter of PSIR is applicable in gadolinium dynamic study of uterine corpus.

Evaluation of uterine peristalsis using cine MRI on the coronal plane in comparison with the sagittal plane

BACKGROUND

Uterine peristalsis is supposed to be closely related to the early stages of reproduction. Sperms are preferentially transported from the uterine cervix to the side of the tube with the dominant follicle. However, with respect to magnetic resonance imaging (MRI), uterine peristalsis has only been evaluated at the sagittal plane of cine MRI.

PURPOSE

To evaluate and compare uterine peristalsis both on sagittal and coronal planes using cine MRI.

MATERIAL AND METHODS

Internal ethics committee approval was obtained, and subjects provided informed written consent. Thirty-one women underwent MRI scans in the periovulatory phase of the menstrual cycle. Cine MR images obtained by fast advanced spin echo sequence at 3-T field strength magnet (Toshiba Medical Systems) were visually evaluated by two independent radiologists. The frequency and the direction of peristalsis, and the presence of outer myometrium conduction of signal intensities (OMC), were evaluated. The laterality of the dominant follicle was determined on axial images and compared with the peristaltic direction in fundus.

RESULTS

The subjects in which peristaltic directions were more clearly recognized were significantly frequent in coronal planes than in sagittal planes (P < 0.05). There was no significant difference in the peristaltic frequency between the sagittal and the coronal plane. However, the OMC was more recognized in the coronal plane than in the sagittal plane (P < 0.05). Peristaltic waves conducted toward the possible ovulation side were observed in only three of the 10 subjects.

CONCLUSION

OMC of uterine peristalsis was better demonstrated in the coronal plane compared to the sagittal plane.

A Layer of Decreased Apparent Diffusion Coefficient at the Endometrial-Myometrial Junction in Uterine Adenomyosis

OBJECTIVES

To assess the detectability of a low-signal-intensity line within adenomyosis lesions adjacent to the endometrium on apparent diffusion coefficient (ADC) maps, and to establish correlations between these lesions and their possible causes, and more particularly the hormonal changes and magnetic resonance (MR) factors.

MATERIALS AND METHODS

MR images were obtained from 110 patients with adenomyosis (age 30-57 y.o.) using 3.0 T or 1.5 T MR units. Recognition of the low-signal-intensity line on ADC map was scored using confidence level. The correlation between recognition of the line and the following factors were examined: magnetic field strength, age group, menstrual cycle phases, history of delivery, and hormonal treatments. Presence of the structure corresponding to the low-signal-intensity line on ADC map was evaluated pathologically in the cases that underwent surgery.

RESULTS

The low-signal-intensity line visible on ADC map was recognized in 55/110 patients. The visibility of the line was not significantly related to hormonal status, age, history of delivery, or magnetic resonance imaging (MRI) magnet strength. There were no corresponding pathological structures.

CONCLUSION

One half of the adenomyosis patients showed discrepant appearances in T2-weighted (T2WI) vs. ADC map, but no significant relationship with hormonal changes was found in this study. This result may suggest that the low-signal-intensity line within the junctional zone may be related to a functional phenomenon.

Magnetic resonance imaging relaxation times of female reproductive organs

BACKGROUND

Relaxation time of female reproductive organs affects the tissue contrast of magnetic resonance image (MRI), and is used for quantitative analysis.

PURPOSE

To evaluate the relaxation times of normal female reproductive organs in the luteal phase of the menstrual cycle.

MATERIAL AND METHODS

On a 1.5-T MRI, relaxation times were measured in pelvic tissues (endometrium, junctional zone, myometrium, follicle, and stroma) of 32 female healthy volunteers (33.5 ± 6.8 years). The Look-Locker sequence was used to measure T1 relaxation times. Furthermore, a multiple spin-echo method with 32 different echo times was used to measure T2 relaxation times. The images were obtained in the luteal phase of each volunteer's menstrual cycle.

RESULTS

The measured relaxation times (means ± standard deviations) were as follows: endometrium (T1, 1703 ± 147 ms; T2, 214 ± 35 ms), junctional zone (T1, 1168 ± 63 ms; T2, 72 ± 12 ms), myometrium (T1, 1314 ± 103 ms; T2, 138 ± 20 ms), follicle (T1, 2267 ± 49 ms; T2, 603 ± 68 ms), and stroma (T1, 1481 ± 129 ms; T2, 126 ± 29 ms).

CONCLUSION

Reliable MRI measurements of T1 and T2 relaxation times of normal female reproductive organs in the luteal phase of the menstrual cycle are useful as references to recognize the normal value.

Dynamic Changes in the Myometrium during the Third Stage of Labor, Evaluated Using Two-Dimensional Ultrasound, in Women with Normal and Abnormal Third Stage of Labor and in Women with Obstetric Complications

OBJECTIVE

To investigate dynamic changes in myometrial thickness during the third stage of labor.

METHODS

Myometrial thickness was measured using ultrasound at one-minute time intervals during the third stage of labor in the mid-region of the upper and lower uterine segments in 151 patients including: women with a long third stage of labor (n = 30), postpartum hemorrhage (n = 4), preterm delivery (n = 7) and clinical chorioamnionitis (n = 4). Differences between myometrial thickness of the uterine segments and as a function of time were evaluated.

RESULTS

There was a significant linear increase in the mean myometrial thickness of the upper uterine segments, as well as a significant linear decrease in the mean myometrial thickness of the lower uterine segments until the expulsion of the placenta (p < 0.001). The ratio of the measurements of the upper to the lower uterine segments increased significantly as a function of time (p < 0.0001). In women with postpartum hemorrhage, preterm delivery, and clinical chorioamnionitis, an uncoordinated pattern among the uterine segments was observed.

CONCLUSION

A well-coordinated activity between the upper and lower uterine segments is demonstrated in normal placental delivery. In some clinical conditions this pattern is not observed, increasing the time for placental delivery and the risk of postpartum hemorrhage.

3 T MRI uterine peristalsis: comparison of symptomatic fibroid patients versus controls

AIM

To compare uterine peristalsis between symptomatic fibroid patients and normal subjects and to determine the possible effect of fibroid characteristics on uterine peristalsis at high-field magnetic resonance imaging (MRI).

MATERIALS AND METHODS

The present study included 20 symptomatic fibroid patients (age range 39-53 years) and 20 normal subjects (age range 19-46 years). MRI images were obtained during the peri-ovulatory phase using 3 T MRI using a sagittal T2 turbo spin-echo sequence and a half-Fourier acquisition single-shot turbo spin-echo sequence for display on cine mode. Two radiologists independently evaluated the images for the presence of uterine peristalsis by confidence level. In cases where peristalsis was present, the images were also evaluated for peristalsis frequency and direction. For fibroid patients, uterine and index fibroid volume, fibroid burden and index fibroid location were also recorded.

RESULTS

Uterine peristalsis was significantly decreased in symptomatic fibroid patients compared with normal controls (p < 0.01). Peristalsis frequency in fibroid patients was also lower than in normal subjects. Direction of peristalsis was cervix-to-fundus for the majority of fibroid patients and controls. There was no significant relationship between fibroid characteristics, such as uterine volume, index fibroid volume, index fibroid location, and fibroid number in fibroid patients with, and fibroid patients without peristalsis.

CONCLUSION

In women with symptomatic fibroids, the presence of uterine peristalsis is significantly decreased compared to normal controls on 3 T cine MRI. The presence of fibroids appears to disturb the normal conduction of uterine peristalsis and may interfere with fluid (e.g., menses, sperm) transport.

Diffusion tensor imaging (DTI) of the normal human uterus in vivo at 3 tesla: comparison of DTI parameters in the different uterine layers

PURPOSE

To investigate the differences in the fiber architecture and related diffusion tensor imaging (DTI) parameters among different uterine layers of the normal human uterus in vivo at 3 Tesla (T).

MATERIALS AND METHODS

DTI of the uterus was performed for nine healthy women of reproductive age on a 3T scanner. A volume of interest (VOI) was drawn for the outer myometrium (OM), junctional zone (JZ), and endometrium (EM). Apparent diffusion coefficient (ADC), fractional anisotropy (FA), and maximum fiber length were compared using paired Student's t-tests. Fibers were classified into four groups and were visually evaluated.

RESULTS

ADC (×10(-3) mm(2) /s) was highest for OM (1.12), followed by EM (0.97) and JZ (0.83) (OM versus JZ, P < 0.0001; JZ versus EM, P = 0.0001; OM versus EM, P = 0.0057). FA was highest for JZ (0.297), followed by OM (0.257) and EM (0.186) (OM versus JZ, P = 0.0002; JZ versus EM, P < 0.0001; OM versus EM, P < 0.0001). Fibers were longest in OM (42.0 mm), followed by JZ (34.2 mm) and EM (20.0 mm). Circularly oriented fibers were observed in 69% in OM and in 70% in JZ.

CONCLUSION

DTI of the uterus in vivo revealed layer-wise differences in the microstructure of the uterus.

Uterine morphology and peristalsis in women with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is associated with chronic oligo-anovulation and high circulating sex hormone levels. Women with PCOS have an increased risk of developing endometrial cancer. In anovulatory women with PCOS a positive relationship between endometrial thickness and endometrial hyperplasia has been observed. Uterine peristalsis, which has been suggested to be of importance for female fertility, has not previously been studied in PCOS.

PURPOSE

To assess whether women with PCOS have altered endometrial thickness, uterine wall morphology, and peristalsis.

MATERIAL AND METHODS

In this prospective case-control study 55 women with PCOS (mean age, 29.5 years ± 4.5 SD) and 28 controls (27.6 ± 3.2) were examined using magnetic resonance imaging (MRI), assessing thickness of endometrium, junctional zone (JZ), and myometrium, and evaluating the occurrence, frequency (waves/min), strength (amplitude), pattern, and direction of peristalsis. Uterine morphology was also assessed by transvaginal ultrasonography (TVUS).

RESULTS

The endometrium was thinner in PCOS with oligo-amenorrhea compared to controls, also after adjustments for age and BMI (adjusted P = 0.043). There was no difference in thickness of the JZ or the myometrium in cases versus controls. Uterine peristalsis was less commonly observed in women with PCOS than in controls (adjusted P = 0.014).

CONCLUSION

There were no differences in myometrial morphology between PCOS and controls, but the endometrium was thinner in PCOS with oligo-amenorrhea. Based on cine MRI, uterine peristalsis was less common in PCOS than in controls.

What do we know about what happens to myometrial function as women age?

Much has been written about the effects of aging on reproductive function, especially female fertility. Much less is known about how aging may affect the contractility of the smooth muscle within the uterus, the myometrium. The myometrium is active through a woman’s entire life, not just during pregnancy. Here we will discuss briefly the contractile functions of the uterus and the changes it undergoes throughout the stages of a woman’s life from menstruation and the menopause, before evaluating the evidence for any changes in myometrial contractility and responses as women age, with a particular focus on women of advanced maternal age. We present original contractility analysis for the widest data set for human myometrium so far examined, and determine inherent spontaneous activity as well as responses to depolarisation and stimulation with oxytocin. Our data show that in the non-pregnant state there is a significant decrease in contractility for both spontaneous and depolarised-induced contractions, with age. We suggest that muscle atrophy and down regulation of Ca channels may account for this. Interestingly in pregnant myometrium we found a wide range of contractile ability between women and little evidence for decreased spontaneous activity between the ages of 25–40. Oxytocin responses appear to be more affected by aging, a finding that is consistent with previously reported clinical findings, and may partly be the result of membrane lipids such as cholesterol, increasing as women age. The marked differences between the age-related decline of force beyond age 30 in non-pregnant uterus, and the lack of difference in the pregnant state over this period, shows that the uterus retains its ability to respond to gestational hormones. The growth of the pregnant uterus and increase in content of myofibrillar proteins, may abolish any previous age-related force deficit. This finding is consistent with what is apparent for postmenopausal women in their 50s and 60s; that with the appropriate hormonal stimulation the uterus can allow an embryo to implant, and then without further intervention, carry the foetus to term. It is tempting therefore to speculate that unlike other well documented declines in female reproductive functions with age, the myometrium remains able to function into a woman’s 7th decade.

T2* relaxometry mapping of the uterine zones

BACKGROUND

Previous literature demonstrated that the T2* value of the uterine junctional zone was lower than that of peripheral myometrium by using BOLD MR imaging. We expect T2* mapping image may add more information to T2-weighted images of the uterine myometrium.

PURPOSE

To evaluate whether T2* mapping software would reproduce the result of previous report, and to apply the software to benign uterine diseases.

MATERIAL AND METHODS

Five healthy volunteers and 19 patients clinically suspected of having benign pelvic disease were imaged using a 1.5T MR system. All women were of reproductive age, and all provided informed consent. Sagittal T2* images using a multishot EPI sequence were obtained. T2* values were calculated and color T2* maps reconstructed using a T2* fitting tool.

RESULTS

The uterine zones could be identified in all 24 examinations on the T2* maps. In addition, a thin "4th zone" was seen between the endometrium and the JZ (junctional zone) in 19 of 24 examinations. The T2* value of JZ was significantly lower than that of peripheral myometrium (PM) (P < 0.001). No significant difference in the T2* value of the JZ or of PM was noted between normal uterus and uterus with leiomyomas and/or adenomyosis.

CONCLUSION

A quantitative T2* map can easily be obtained using the PRIDE software T2* fitting tool, and the software reproduces the result from previous report. T2* value of the junctional zone was lower than that of peripheral myometrium regardless of having benign myometrial diseases.

A new method for analysis of non-pregnant uterine peristalsis using transvaginal ultrasound

OBJECTIVES

To develop an objective method for analysis of uterine peristalsis using transvaginal sonography (TVS).

METHODS

We performed computerized analysis of 2-5-min video recordings of TVS imaging of a midsagittal cross-section of the uterus during the proliferative and early secretory phases of 18 healthy volunteers aged 28-41 years. The contours of the fluid-endometrial interface (FEI) and the endometrium-myometrium interface (EMI) were detected in each frame, and the data from all frames were used to explore the dynamic motility characteristics of these interfaces at fixed distances from the fundus.

RESULTS

The mean ± SD dominant frequency of peristalsis of the EMI along the midsagittal cross-section was 0.049 ± 0.01 Hz and that of the cavity center was 0.043 ± 0.02 Hz. The maximal amplitudes of the EMI were about 1 ± 0.25 mm, located between 7 and 17 mm from the fundus. The amplitudes of the FEI were in the range 0.05-0.2 mm. The amplitude of the cavity centerline movement was 0.94 ± 0.34 mm, located at the extremes of the unperturbed curve.

CONCLUSIONS

This study provides a simple tool for analysis of uterine peristalsis characteristics using ultrasound data. This is possible at the EMI even when the FEI is invisible or incomplete, such as during the luteal phase, when an intrauterine contraceptive device is in place, and during diagnostic or medical intervention.

Vaginal tactile imaging

Changes in the elasticity of the vaginal walls, connective support tissues, and muscles are thought to be significant factors in the development of pelvic organ prolapse, a highly prevalent condition affecting at least 50% of women in the United States during their lifetimes. It creates two predominant concerns specific to the biomechanical properties of pelvic support tissues: how does tissue elasticity affect the development of pelvic organ prolapse and how can functional elasticity be maintained through reconstructive surgery. We designed a prototype of vaginal tactile imager (VTI) for visualization and assessment of elastic properties of pelvic floor tissues. In this paper, we analyze applicability of tactile imaging for evaluation of reconstructive surgery results and characterization of normal and pelvic organ prolapse conditions. A pilot clinical study with 13 patients demonstrated that VTI allows imaging of vaginal walls with increased rigidity due to implanted mesh grafts following reconstructive pelvic surgery and VTI has the potential for prolapse characterization and detection.

Intrauterine devices and uterine peristalsis: evaluation with MRI

Intrauterine devices (IUDs) have been viewed as an effective form of contraception. However, the mechanism by which IUDs disturb fertility remains controversial. This study aimed to evaluate the effects of IUDs on uterine contractility using cine MR. Eleven healthy female volunteers of reproductive age bearing IUDs and 12 women not bearing IUDs were evaluated during the periovulatory phase. MR images were obtained with a 1.5-T magnet, acquiring 60 serial images every 3 s via half-Fourier acquisition single-shot turbo spin echo to be displayed on cine mode. Assessments were based on (a) the presence of peristaltic waves, (b) the frequency and direction of peristaltic waves and (c) the extent of peristaltic waves. Static images were evaluated for thickness of the junctional zone (JZ) and myometrium. A fundo-cervical (FC)-directed peristaltic wave was identified in 4 of 11 IUD-bearing subjects and in only 1 of 12 subjects from the control group. FC waves extended through more than half of the thickness of the myometrium. Peristaltic frequency in IUD users (5.0/3 min) was less than that of the control group (6.5/3 min). The JZ and myometrium were significantly thicker in IUD users. FC-directed waves were more often observed in IUD-bearing subjects, which might explain the inhibition of active sperm transport.

Functional MR imaging of the female pelvis

Recent developments in MR techniques have magnified the roles and potential of MRI in the female pelvis. This article reviews the techniques and clinical applications of functional MRI (fMRI) of the female pelvis, including cine MRI, diffusion-weighted MRI (DWI), and dynamic contrast-enhanced (DCE)-MRI. Cine MRI is a useful tool for evaluating uterine contractility, including sustained contraction and peristalsis, in a variety of conditions and gynecologic disorders, and for evaluating pelvic-floor weakness. DWI can demonstrate abnormal signals in pathologic foci based on differences in molecular diffusion. It also enables the quantitative evaluation of the apparent diffusion coefficient (ADC), which may be useful for distinguishing malignant from benign tissues and monitoring therapeutic outcome. DCE-MRI has the potential to improve tumor detection and local staging, and can also provide quantitative information about perfusion of the tumor, which may be useful for both monitoring therapeutic effects and predicting therapeutic outcome. Understanding the roles played by functional MR techniques in the female pelvic region is beneficial not only for determining clinical applications, but also for developing further investigations with MRI.

Magnetic resonance imaging of benign uterine pathology

Magnetic resonance imaging is commonly used for the identification and characterization of many pelvic abnormalities. Magnetic resonance provides the most comprehensive and detailed view of the uterus of any imaging modality. This article focuses on the magnetic resonance imaging features used to recognize and describe congenital uterine anomalies and benign conditions of the uterus.

Uterine Contractility Evaluated on Cine Magnetic Resonance Imaging

The inherent contractility of the uterus has attracted concern of researchers and exhibits two known patterns of contraction. One is focal and sporadic bulging of the myometrium, and the other is rhythmic and subtle stripping movement in the subendometrial myometrium, known as uterine peristalsis. Recent development in the ultrafast magnetic resonance imaging (MRI) techniques has enabled us to observe these uterine contractions directly and noninvasively. Although the mechanisms and relationship of these two kinds of myometrial contractions and their relations to age, pharmaceutical administration such as oral contraceptives (OCs), and a variety of gynecologic and obstetrical problems are still under debate, cine MRI can be applied for directly monitoring changes of the uterus related to important uterine functions such as fertility and menstrual problems.

A comparison of uterine peristalsis in women with normal uteri and uterine leiomyoma by cine magnetic resonance imaging

OBJECTIVE

The non-pregnant uterus shows wave-like activity (uterine peristalsis). This pilot study was intended to determine: (1) whether uterine peristalsis during the menstrual cycle is detectable by cine magnetic resonance imaging (MRI); (2) the effects of leiomyoma on uterine peristalsis.

STUDY DESIGN

Mid-sagittal MRI was performed sequentially with T2-weighted single-shot fast spin-echo (SSFSE) in 3 normal ovulatory volunteers and 19 premenopausal women with uterine leiomyoma. Direction and frequency of movement of the junctional zone were evaluated using a cine mode display.

RESULTS

Junctional zone movement was identified in all subjects. Direction of uterine peristalsis in normal volunteers was fundus-to-cervix during menstruation, cervix-to-fundus during the periovulatory phase, and isthmical during the mid- and late-luteal phases. Abnormal peristaltic patterns were detected in three of five patients with uterine leiomyoma during menstruation and in the mid-luteal phase of the cycle, respectively.

CONCLUSION

Cine MRI is a novel method for evaluation of uterine peristalsis. Results of this pilot study suggest that abnormal uterine peristalsis during menstruation and the mid-luteal phase might be one of the causes of hypermenorrhea and infertility associated with uterine leiomyoma.