Changes in apparent diffusion coefficients in the normal uterus during different phases of the menstrual cycle

Magnetic resonance imaging features of complete androgen insensitivity syndrome in comparison to Mayer-Rokitansky-Küster-Hauser syndrome

PURPOSE

Complete androgen insensitivity syndrome (CAIS) and Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) share common clinical features such as female phenotype, vaginal hypoplasia, and primary amenorrhea. Magnetic resonance imaging (MRI) is performed to investigate the cause of primary amenorrhea. However, the MRI features are also similar in both disorders. They are ultimately diagnosed by chromosome testing, but there is a possibility of misdiagnosis if chromosome testing is not performed. This study aimed to identify MRI features that are useful for differentiating CAIS from MRKHS.

METHOD

This multicenter retrospective study included 12 patients with CAIS and 19 patients with MRKHS. Three radiologists blindly evaluated the following features: (1) detection of vagina, (2) detection of nodular and cystic structures in the lateral pelvis; undescended testicles and paratesticular cysts in CAIS and rudimentary uteri and ovaries in MRKHS, (3) their location, (4) number of cysts in the cystic structures, and (5) signal intensity on diffusion-weighted images (DWI) and apparent diffusion coefficient (ADC) values of the nodular structures. Statistical comparisons were performed using Mann-Whitney U and Fisher's exact tests.

RESULTS

Compared with MRKHS, the CAIS group showed significantly detectable vagina, more ventrally located nodular and cystic structures, fewer cysts within the cystic structures, and nodular structures with higher signal intensity on DWI and lower ADC values.

CONCLUSIONS

MRI features of detectable vagina, location of nodular and cystic structures, number of cysts within the cystic structures, signal intensity on DWI and ADC values of the nodular structures were useful in differentiating CAIS from MRKHS.

Clinical Utility of Diffusion-Weighted Imaging in Gynecological Imaging: Revisited

ABSTRACT

Diffusion-weighted imaging (DWI) is an increasingly valuable sequence in daily clinical practice, providing both functional and morphological information. The use of DWI can help quantify diffusion using the apparent diffusion coefficient, which reflects the physiological features of the tissue and tumor microcirculation. This knowledge is crucial for understanding and interpreting gynecological imaging. This article reviews the clinical utility of DWI for gynecological imaging, highlighting its ability to aid in the detection of endometrial and cervical cancers, as well as tumor extension and metastasis. In addition, DWI can easily detect the solid components of ovarian cancer (including dissemination), assist in the diagnosis of adnexal torsion, and potentially show bone marrow status. Apparent diffusion coefficient measurement is useful for differentiating between endometrial lesions, uterine leiomyomas, and sarcomas, and may provide important information for predicting the prognosis of gynecological cancers.

Field-of-view optimized and constrained undistorted single-shot study of intravoxel incoherent motion and diffusion-weighted imaging of the uterus during the menstrual cycle: a prospective study

PURPOSE

This study aimed to compare the variability of the uterus during the menses phase (MP), follicular phase (FP), and luteal phase (LP) of the menstrual cycle using intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI).

METHODS

This prospective study was conducted at the Guangdong Provincial Hospital of Traditional Chinese Medicine between January 2022 and January 2023. Women of childbearing age (18-45 years) with appropriate progesterone levels were included in this study. Conventional magnetic resonance imaging and IVIM-DWI scans were performed during the MP, FP, and LP. The differences in IVIM-DWI-derived parameters between these phases were then compared, and the overlap was quantitatively described.

RESULTS

The apparent diffusion coefficient (ADC) and pure molecular diffusion coefficient (D) values from the endometrium, uterine junctional zone (UJZ), and myometrium indicated statistical differences between the MP and FP and the MP and LP (ADC: endometrium, both P < 0.001; UJZ, P = 0.008 and P < 0.001, respectively; myometrium, P = 0.033 and P = 0.006, respectively; D: endometrium, both P < 0.001; UJZ, P = 0.008 and P = 0.006, respectively; myometrium, P = 0.041 and P = 0.045, respectively). The perfusion-related diffusion coefficient (D*) values from the myometrium indicated statistical differences between the FP and MP and the FP and LP (D*: myometrium, P = 0.049 and P = 0.009, respectively). The overlapping endometrium ratios between the MP and FP or LP were lower than 50% in the ADC and D values (ADC: overlapping of MP and FP: 33.33%, overlapping of MP and LP: 23.33%; D: overlapping of MP and FP: 40.00%, overlapping of MP and LP: 43.33%).

CONCLUSION

The ADC and IVIM-derived parameters indicated differences in the uterus in diverse phases of the menstrual cycle, especially in the endometrium in relation to ADC and D values.

Magnetic resonance imaging thicknesses and apparent diffusion coefficient values of the endometrium and junction zone in women of reproductive age

BACKGROUND

The endometrium and uterine junction zone often change throughout the menstrual cycle. Some pathological conditions may appear normal in uterine imaging, which will lead to missed diagnosis and misdiagnosis.

PURPOSE

To evaluate the changes in the thickness and apparent diffusion coefficient (ADC) values of the endometrium and uterine junction zone throughout the menstrual cycle in magnetic resonance imaging (MRI) of women of reproductive age.

MATERIAL AND METHODS

Data were collected from 40 healthy women of reproductive age with regular menstrual cycles from January 2017 to April 2018. They underwent four total MRI sessions during the menstrual, proliferation, and early and late secretive phases. The main MRI sequences were T2-weighted (T2W) volume isotropic turbo spin echo acquisition (VISTA) spectral attenuated inversion recovery (SPAIR) and diffusion-weighted imaging (b = 0, 600, 800, 1000 s/mm²), which were used to measure the thicknesses and ADC values of endometrium and uterine junction zone.

RESULTS

First, the endometrium was thinnest during the menstrual phase and thickest in the late secretive phase. Second, the uterine junction zone was thinnest in the late secretive phase and thickest in the menstrual phase. Third, the ADC values of the endometrium were lowest in the menstrual phase and peaked in the early secretive phase. Finally, the ADC values of the uterine junction zone were lowest in the menstrual phase and peaked in the late secretive phase.

CONCLUSION

The endometrium and uterine junction zone showed cyclic changes. Radiologists should consider these changes in the thickness and ADC values when analyzing MRI images of the uterus.

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.

Drug delivery strategies for management of women's health issues in the upper genital tract

The female upper genital tract (UGT) hosts important reproductive organs including the cervix, uterus, fallopian tubes, and ovaries. Several pathologies affect these organ systems such as infections, reproductive issues, structural abnormalities, cancer, and inflammatory diseases that could have significant impact on women's overall health. Effective disease management is constrained by the multifaceted nature of the UGT, complex anatomy and a dynamic physiological environment. Development of drug delivery strategies that can overcome mucosal and safety barriers are needed for effective disease management. This review introduces the anatomy, physiology, and mucosal properties of the UGT and describes drug delivery barriers, advances in drug delivery technologies, and opportunities available for new technologies that target the UGT.

The Role of Abnormal Uterine Junction Zone in the Occurrence and Development of Adenomyosis

Adenomyosis is a benign disease with a malignant behavior, bothering a lot of women at reproductive age who suffer from increased menstruation, prolonged menstruation, progressive dysmenorrhea, and infertility. At present, there is no effective treatment for adenomyosis. It seriously affects the life quality of these patients. However, the pathogenesis of adenomyosis is not yet clear. Recently, uterus junctional zone, defined as the inner 1/3 of myometrium between endometrium and myometrium, has gained broad attention. As is reported, the structure and function disorder of uterus junctional zone may play an important part in the occurrence and development of adenomyosis. In this issue, the present study generally reviews the role of uterine junction zone and the related mechanisms involved in adenomyosis, such as the local micro-damage, the formation of inflammatory and hypoxic microenvironment, changes of cytokines, and abnormalities of miRNA as well as signal pathways. It will provide new insights and potential therapeutic target strategies for clinical strategies in the management of adenomyosis.

Initial Experience With Diffusion-Weighted Magnetic Resonance Imaging for the Evaluation of Endometrial Fibrosis

OBJECTIVE

This study aimed to determine the feasibility of diffusion-weighted imaging for detecting endometrial fibrosis in patients with intrauterine injury.

METHODS

This prospective study included 34 patients with endometrial fibrosis and 34 healthy controls. All participants underwent T2-weighted and diffusion-weighted magnetic resonance imaging with b values of 0 and 1000 s/mm2 during the periovulatory phase with a dominant follicle. The endometrial apparent diffusion coefficient (ADC) and uterine anatomical parameters (endometrial thickness [EMT], length of the uterine cavity [LUC], and junctional zone thickness [JZT]) were measured and compared. Performance of the uterine endometrial ADC and anatomical parameters in diagnosing endometrial fibrosis was evaluated.

RESULTS

Patients with endometrial fibrosis showed a lower endometrial ADC, lower EMT, shorter LUC, and higher JZT than did healthy controls (all, P < 0.001). Endometrial ADC value and uterine anatomical parameters showed good performance in diagnosing endometrial fibrosis, with the areas under the receiver operating characteristic curves of 0.976, 0.870, 0.883, and 0.864, respectively. The area under the curve of ADC was significantly higher than those of EMT (z = 1.973, P = 0.0485), LUC (z = 2.059, P = 0.0395), and JZT (z = 2.484, P = 0.0130). Intraobserver and interobserver agreements of endometrial ADC value measurements were excellent for both patients (intraclass correlation coefficient = 0.987 and 0.983, respectively) and healthy women (intraclass correlation coefficient = 0.986 and 0.989, respectively).

CONCLUSIONS

Our preliminary results suggest that diffusion-weighted imaging has the potential to be a noninvasive imaging tool for the quantitative assessment of endometrial fibrosis.

Influence of menstrual status and pathological type on the apparent diffusion coefficient in cervical cancer: a primary study

BACKGROUND

Apparent diffusion coefficient (ADC) value is an important quantitative parameter in the research of cervical cancer, affected by some factors.

PURPOSE

To investigate the effect of pathological type and menstrual status on the ADC value of cervical cancer.

MATERIAL AND METHODS

A total of 352 individuals with pathologically confirmed cervical cancer between January 2015 to December 2017 were retrospectively enrolled in this study, including 317 cases with squamous cell carcinomas (SCC) and 35 cases with adenocarcinomas (AC); 177 patients were non-menopausal and 175 were menopausal. All patients underwent a routine 3.0-T magnetic resonance imaging (MRI) scan and diffusion-weighted imaging (DWI) examination using b-values of 0, 800, and 1000 s/mm². Three parameters including mean ADC (ADC_mean), maximum ADC (ADC_max), and minimum ADC (ADC_min) of cervical cancer lesions were measured and retrospectively analyzed. Independent samples t-test was used to compare the difference of ADC values in different menstrual status and pathological types.

RESULTS

In all menopausal and non-menopausal patients, the ADC_mean and ADC_min values of SCC were lower than those of AC (P<0.05), the ADC_max of two pathological types showed no statistical difference (P > 0.05). In menopausal patients, the ADC_mean, ADC_max, and ADC_min values of SCC were not statistically different compared with those of AC (P > 0.05). The ADC_mean, ADC_max, and ADC_min values of different pathological types cervical cancers in non-menopausal patients were all higher than those in menopausal patients (P<0.05).

CONCLUSION

The ADC values of the cervical cancers were different in different pathological types and were also affected by menstrual status.

The importance of the junctional zone of the endometrium in human reproduction

Junctional zone endometrium (JZE) thickness and contractility seem to determine gamete and embryo transportation and implantation. Proper function depends on concentration levels, mode and timing of oestrogen and progesterone production. Most probably, the remodelling of spiral arteries, and the development of endometrium and decidua are also highly dependent on JZE activity. Fibroids that are adjacent to JZE affect JZE contractility contributing to abnormal or failed implantation. Disruption of the JZE continuity provokes adenomyosis, a condition that causes chronic inflammation and fibrosis, which negatively affects the normal function of JZE. Imaging by magnetic resonance imaging and three-dimensional sonography can diagnose JZE abnormal appearance, alterations in thickening and contractility frequency, usually in the advanced stage of the disease. Failures of assisted reproduction, and adverse early pregnancy outcomes have also been associated with abnormal JZE. Altered uterine contractions due to JZE changes are strongly associated with poor reproductive outcome and early pregnancy loss. Endometriosis and adenomyosis prevalently co-exist, with clear relation and negative effects on the JZE. The presence of endometriosis should alert to the possibility of coexisting adenomyosis. Co-existence of endometriosis may mask the extent of the negative impact of adenomyosis in infertility.

Variability of apparent diffusion coefficient in the brain in women during follicular and luteal phases of the menstrual cycle

PURPOSE

To investigate the variability of apparent diffusion coefficient (ADC) in the brain in women during follicular and luteal phases of the menstrual cycle.

METHODS

The present study included 32 females of reproductive age with regular menstruation. The participants were divided into two groups as group 1: females in the follicular phase, and group 2: females in the luteal phase. The regions of interest were manually drawn on the structures of the T2-weighted images (frontal gray and white matter, parietal gray and white matter, temporal gray and white matter, occipital gray and white matter, cerebellar gray and white matter, caudate nucleus, putamen, thalamus, internal capsule, pons, cerebrospinal fluid (CSF) in the frontal and in the occipital horn of the lateral ventricle and CSF in the middle part of the lateral ventricle). ADC values were averaged for each patient. We used Kruskal-Wallis ANOVA for more than two groups but used Mann Whitney U test for comparison of ADC values between the group of 18 females in the follicular phase and the group of 14 females in the luteal phase.

RESULTS

No statistically significant differences were observed among the groups in terms of the ADC value of each neuroanatomic structure that was evaluated.

CONCLUSION

We did not determine a significant difference among volunteers at the two different phases of the menstrual cycle in terms of ADC values measured from different regions of the brain. However, although not statistically significant, ADC values measured from almost all parts of the brain were higher at the luteal phase than at the follicular phase.

Diffusion Tensor Imaging of the Uterine Zones Related to the Menstrual Cycle and Menopausal Status at 3 Tesla MRI

BACKGROUND

Diffusion and diffusion tensor imaging techniques (DTI) are widely available and used both in central nervous system and body imaging, including gynecological diseases.

AIMS

The aims of this study were to assess the capability of DTI of uterine zones in relation to the menstrual cycle and ascertain the normal apparent diffusion coefficient and fractional anisotropy values at 3T magnetic resonance imaging (MRI).

STUDY DESIGN

Prospective clinical study.

METHODS

A total of 13 young reproductive and 12 postmenopausal healthy volunteers were included in the study. MRI examination included sagittal T2-weighted and single-shot echo planar imaging DTI obtained under free breathing. Fractional anisotropy (FA) values of the endometrium, junctional zone, and myometrium were determined.

RESULTS

The median (minimum-maximum) FA of the endometrium, myometrium, and junctional zone of the reproductive group were 0.31 (0.260-0.465), 0.42 (0.302-0.664), and 0.58 (0.420-0.745), respectively, in the proliferative phase and 0.26 (0.180-0.413), 0.48 (0.357-0.656), and 0.59 (0.490-0.675)], respectively, in the secretory phase. In the postmenopausal group, the FA values of the endometrium, myometrium, and junctional zone were 0.275 (0.136-0.425), 0.255 (0.191-0.553), and 0.27 (0.129-0.397), respectively. Apparent diffusion coefficient (ADC) values of the endometrium, myometrium, and junctional zone of the reproductive group were 1.25±0.254 (0.970-1.463), 1.67 (1.213-1.854), and 1.23 (0.853-1.301), respectively, in the proliferative phase and 1.32±0.283 (1.165-1.706), 1.55 (1.360-1.791), and 1.17 (1.163-1.705), respectively, in the secretory phase. In the postmenopausal group, the ADC values of the endometrium, myometrium, and junctional zone were measured as 1.100±0.192 (0.850-1.302), 1.14 (0.864-1.283), and 1.09 (0.912-1.291). The FA values of the endometrium and myometrium were lower in the secretory phase of the reproductive group, while ADC values were higher. However, both the FA and ADC values were lower in the postmenopausal group.

CONCLUSION

The present study showed that uterine DTI is feasible when used quantitatively. While FA values tend to decrease, ADC values increase significantly in all zones in the secretory phase except the junctional zone. Zonal FA and ADC values of postmenopausal women are lower in comparison to those in young women.

Perfusion and diffusion characteristics of endometrial malignancy based on intravoxel incoherent motion MRI at 3.0 T: comparison with normal endometrium

BACKGROUND

There has been a growing need for a non-invasive imaging method for the accurate diagnosis and differentiation of endometrial malignancy (EM).

PURPOSE

To study tissue characteristics of EM using an intravoxel incoherent motion (IVIM) model and to assess their diagnostic potential.

MATERIAL AND METHODS

Sixty-eight EMs and 31 healthy participants were prospectively recruited for diffusion-weighted (13 b-values, b = 0-3,000 s/mm(2)) and standard magnetic resonance imaging (MRI). A bi-exponential analysis was performed to derive f (perfusion fraction), D* (pseudodiffusion coefficient), and D (true diffusion coefficient) in EM and normal endometrium (NE). Apparent diffusion coefficient (ADC) was calculated. Student's t test, the Mann-Whitney U test and a receiver operating characteristics (ROC) curve analysis were performed.

RESULTS

EM had lower f (37.809 ± 12.158%) and was significantly different from NE (P < 0.001). However, the EMs had higher D (0.503 ± 0.155 × 10(-3) mm(2)/s) and D* (19.796 ± 20.029 × 10(-3) mm(2)/s) and were all significantly different from NE (P < 0.001). D was significantly lower than ADC in NE (P < 0.001) but not in EM (P > 0.05). f ≤ 48.5%, D > 0.432 × 10(-3) mm(2)/s, D* > 4.94 × 10(-3) mm(2)/s, and ADC ≤ 0.542 × 10(-3) mm(2)/s could diagnose EM (AUC 0.786-0.961).

CONCLUSION

EM has distinctive IVIM perfusion and diffusion characteristics with promising potential for earlier non-invasive diagnosis.

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.

Diffusion-weighted and diffusion-tensor imaging of normal and diseased uterus

Owing to technical advances and improvement of the software, diffusion weighted imaging and diffusion tensor imaging (DWI and DTI) greatly improved the diagnostic value of magnetic resonance imaging (MRI) of the pelvic region. These imaging sequences can exhibit important tissue contrast on the basis of random diffusion (Brownian motion) of water molecules in tissues. Quantitative measurements can be done with DWI and DTI by apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values respectively. ADC and FA values may be changed by various physiological and pathological conditions providing additional information to conventional MRI. The quantitative DWI assists significantly in the differentiation of benign and malignant lesions. It can demonstrate the microstructural architecture and celluler density of the normal and diseased uterine zones. On the other hand, DWI and DTI are useful for monitoring the treatment outcome of the uterine lesions. In this review, we discussed advantages of DWI and DTI of the normal and diseased uterus.

3-T diffusion tensor imaging (DTI) of normal uterus in young and middle-aged females during the menstrual cycle: evaluation of the cyclic changes of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values

OBJECTIVE

To evaluate cyclic changes of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of normal uterus in different age groups during the menstrual cycle, and the correlation with serum female hormone levels.

METHODS

29 normal volunteers accepted diffusion tensor imaging of the uterus on menstrual phase (MP), follicular phase (FP), ovulatory phase (OP) and luteal phase. FA and ADC values of different uterine layers on midsagittal images were measured. Differences between two age groups during the menstrual cycle were evaluated using liner mixed models and one-way analysis of variance. Pearson correlation analysis compared variation of FA and ADC values with serum female hormone levels measured in MP.

RESULTS

During menstrual cycle, endometrial FA values declined, whereas ADC values increased with significant differences (p < 0.05). Serum oestradiol (E) levels correlated moderately with variations of FA values between MP-FP (p = 0.045; r = 0.389) and MP-OP (p = 0.008; r = 0.511). FA and ADC values of junctional zones showed no significant difference (p > 0.05) as well as FA values of myometrium (p = 0.0961), while ADC values of myometrium showed significant increase from menstrual phase to luteal phase (p < 0.05). FA and ADC values of uterine three zonal structures showed significant differences (p < 0.05) at each phase during the menstrual cycle. No significant difference of FA and ADC values was found between age groups (p > 0.05).

CONCLUSION

Dynamic changes of uterine FA and ADC values were observed during menstrual cycle. Variation of FA values between MP-FP, MP-OP correlated moderately with serum E levels.

ADVANCES IN KNOWLEDGE

No publications on the relationship between FA and ADC values and the female hormone levels were found; our study prospectively investigated the cyclic changes of FA and ADC values of the normal uterus and the correlation with the basic serum female hormone levels in MP.

A stochastic model for early placental development

In the human, placental structure is closely related to placental function and consequent pregnancy outcome. Studies have noted abnormal placental shape in small-for-gestational-age infants which extends to increased lifetime risk of cardiovascular disease. The origins and determinants of placental shape are incompletely understood and are difficult to study in vivo. In this paper, we model the early development of the human placenta, based on the hypothesis that this is driven by a chemoattractant effect emanating from proximal spiral arteries in the decidua. We derive and explore a two-dimensional stochastic model, and investigate the effects of loss of spiral arteries in regions near to the cord insertion on the shape of the placenta. This model demonstrates that disruption of spiral arteries can exert profound effects on placental shape, particularly if this is close to the cord insertion. Thus, placental shape reflects the underlying maternal vascular bed. Abnormal placental shape may reflect an abnormal uterine environment, predisposing to pregnancy complications. Through statistical analysis of model placentas, we are able to characterize the probability that a given placenta grew in a disrupted environment, and even able to distinguish between different disruptions.

MRI appearances of benign uterine disease

Benign uterine disease is a common entity affecting women of all ages. Ultrasound has historically been the predominant imaging method used in the evaluation of benign gynaecological disease, magnetic resonance imaging (MRI) being reserved for use in the staging of malignant uterine and cervical disease. MRI is now increasingly used in the diagnosis of benign uterine disease as well as a tool for problem-solving in cases of diagnostic dilemma. It allows detailed assessment of benign conditions, such as endometrial lesions, leiomyomas, and adenomyosis, and can be helpful in the stratification of patients to different treatment modalities, including surgical resection, uterine artery embolization, and medical therapies. In this article, we review the MRI findings in the common benign uterine diseases.

Apparent diffusion coefficients of normal uterus in premenopausal women with 3 T MRI

AIM

To investigate the apparent diffusion coefficient (ADC) values of the normal uterine cervical zonal structures (cervical epithelium, the junctional zone, and myometrium) during different phases of the menstrual cycle among premenopausal women in different age groups.

MATERIALS AND METHODS

Seventy healthy women, who were divided into three age groups (group A, 24 women in their twenties; group B, 23 women in their thirties; group C, 23 women in their forties), underwent 3 T magnetic resonance imaging (MRI) with T2-weighted and diffusion-weighted imaging (DWI) during the mid-proliferative and the mid-secretory phases.

RESULTS

The ADC values of each cervical zonal structure were significantly different from one another (p < 0.001). The ADC values of the epithelium and junctional zones were both lower during the mid-secretory phase than those during the mid-proliferative phase in each age group (p < 0.05). There were no significant differences in the ADC values of any of the cervical zones among the three age groups for a given phase (p > 0.05).

CONCLUSION

ADC values of normal cervical epithelium and the junctional zone change with different phases of the menstrual cycle, which should be taken into consideration when early cervical disease is detected, when monitoring treatment response, and differentiating early tumour recurrence.

Diffusion-weighted magnetic resonance imaging of the normal endometrium: temporal and spatial variations of the apparent diffusion coefficient

BACKGROUND

Diffusion-weighted magnetic resonance imaging (DWI) is increasingly used in the diagnosis of endometrial disease. No complete knowledge, however, exists yet of the influence of physiology on the endometrial apparent diffusion coefficient (ADC) values on which DWI is based.

PURPOSE

To establish whether the ADC values measured with DWI in the endometrium of healthy reproductive-aged women significantly vary from the early proliferative to the periovulatory phase of the menstrual cycle and between the fundus and the isthmus of the uterus.

MATERIAL AND METHODS

In 17 women the endometrial ADC values measured on the fifth menstrual day, both at the fundus and at the isthmus of the uterus, were compared to the values obtained on the 14th day before the subsequent cycle. In 81 women (menstrual day: fifth through 21st) the endometrial ADC values measured at the fundus were compared to the values obtained at the isthmus of the uterus. All examinations were performed with a 1.5 T magnet (b values: 0 and 800 mm/s(2)). The results were analyzed by means of Student's t-test per paired data.

RESULTS

The endometrial ADC values measured on the fifth day of the menstrual cycle were lower than those obtained in the periovulatory phase both at the fundus (mean 0.923 vs. 1.256 × 10(-3) mm(2)/s) and at the isthmus (mean 1.297 vs. 1.529 × 10(-3) mm(2)/s) of the uterus. The endometrial ADC values measured at the fundus of the uterus were lower than those obtained at the isthmus (mean 1.132 vs. 1.420 × 10(-3) mm(2)/s) through the menstrual cycle. All these differences were highly significant (P < 0.001) at statistical analysis.

CONCLUSION

Physiological variations occurring in endometrial ADC values of healthy women should be considered by the radiologists when interpreting DWI examinations in patients with endometrial disease.

Apparent diffusion coefficients of normal uterus in premenopausal women with 3.0-T magnetic resonance imaging. J Comput Assist Tomogr. 2012;36:54-59. [PMID: 22261770 DOI: 10.1097/rct.0b013e3182418885]

PURPOSE

To investigate the apparent diffusion coefficients (ADCs) of the normal uterine zonal structures (myometrium, endometrium, and junctional zone) during different phases of the menstrual cycle among premenopausal women with different age groups.

MATERIALS AND METHODS

Magnetic resonance (MR) images of 67 healthy women were obtained during the midproliferative and midsecretory phases. They were further divided into 3 age groups: group A (age range, 20-29 years); group B (age range, 30-39 years), and group C (mean age, 44.62 years; age range, 40-49 years). All the women underwent 3.0-T MR scanning twice. The ADC values were compared among each uterine zonal structure and 3 age groups and were calculated between the midproliferative and midsecretory phase.

RESULTS

The ADC values among each uterine zonal structures were significantly different from one another (P < 0.001). The ADC values for endometrium in women in their 30s were higher than those in their 20s and in their 30s during the midproliferative and midsecretory phases (P < 0.05), and the ADC values for endometrium in each age groups were lower during the midproliferative phase than those during the midsecretory phase (P < 0.05), but there were no statistical differences in the myometrium and the junctional zone between the 2 phases or among age groups (P > 0.05).

CONCLUSION

These preliminary results suggested that the zone, age, and phase of the menstrual cycle in premenopausal women should be considered when interpreting the ADC values of uterine structures (especially for endometrium).

Diffusion-weighted MR imaging in gynecologic cancers

Diffusion-weighted imaging (DWI) reflects changes in proton mobility caused by pathological alterations of tissue cellularity, cellular membrane integrity, extracellular space perfusion, and fluid viscosity. Functional imaging is becoming increasingly important in the evaluation of cancer patients because of the limitations of morphologic imaging. DWI is being applied to the detection and characterization of tumors and the evaluation of treatment response in patients with cancer. The advantages of DWI include its cost-effectiveness and brevity of execution, its complete noninvasiveness, its lack of ionizing radiation, and the fact that it does not require injection of contrast material, thus enabling its use in patients with renal dysfunction. In this article, we describe the clinical application of DWI to gynecological disorders and its diagnostic efficacy therein.

Apparent diffusion coefficient values of the normal uterus: Interindividual variations during menstrual cycle

OBJECTIVES

To assess the apparent diffusion coefficient (ADC) changes of the normal uterine zones among reproductive women during the menstrual cycle.

METHODS

The study included 101 women of reproductive age, each with regular cycle and normal endometrium/myometrium, as proved on histopathology or MR imaging examination. Diffusion-weighted (DW) imaging was performed along the axial plane, using a single shot, multi-slice spin-echo planar diffusion pulse sequence and b-values of 0 and 800s/mm(2). The mean and standard deviation of the ADC values of normal endometrium/myometrium were calculated for menstrual, proliferative and secretory phase. Analysis of variance followed by the least significant difference test was used for statistical analysis.

RESULTS

The ADC values of the endometrium were different in the three phases of the menstrual cycle (menstrual phase: 1.25±0.27; proliferative phase: 1.39±0.20; secretory phase: 1.50±0.18) (F: 9.64, p: 0.00). Statistical significant difference was observed among all groups (p<0.05). The ADC values of the normal myometrium were different in the three phases of the menstrual cycle (menstrual phase: 1.91±0.35; proliferative phase: 1.72±0.27; secretory phase: 1.87±0.28) (F: 3.60, p: 0.03). Statistical significant difference was observed between menstrual and proliferative phase and between proliferative and secretory phase (p<0.05). No significant difference was noted between menstrual and secretory phase (p>0.05).

CONCLUSIONS

A wide variation of ADC values of normal endometrium and myometrium is observed during different phases of the menstrual cycle.

Diffusion-weighted Magnetic Resonance Imaging: What Makes Water Run Fast or Slow?

Diffusion-Weighted Magnetic Resonance Imaging (DWI) obtains information useful in diagnosing several diseases through the measurement of random, Brownian diffusion of water molecules in tissues. This pictorial essay illustrates the main factors, i.e., ratio between the volume occupied by cells and the extracellular space, composition of the extracellular space, and temperature, that determine the rate of the water diffusion. The mechanism through which these influencing factors affect water diffusion is explained. Clinical and experimental examples, derived both from physiology and from non-human models, are described.