Evaluation of the cervix tissue homogeneity by ultrasound elastography in infertile women for the prediction of embryo transfer ease: a diagnostic accuracy study

Advancements in the application of uterine ultrasound elastography

PURPOSE OF REVIEW

This article reviews recent advances in ultrasound elastography in diagnosing and evaluating the normal nongravid uterus and the infertile uterus in the gynecologic patient.

RECENT FINDINGS

Focusing on the most recent primary literature, studies have demonstrated new findings among a breadth of gynecologic clinical settings. Studies in the nongravid uterus have found that menopausal status, age, and menstrual phase have not been associated with changes in uterine tissue stiffness. Focusing on myometrial disease, there have been conflicting data regarding the ability to distinguish uterine fibroids from adenomyosis. One area of expanding research surrounding uterine elastography includes the infertile population, where ongoing studies attempt to provide a predictive model using shear wave elastography (SWE) in patients undergoing in-vitro fertilization.

SUMMARY

Ultrasound elastography has become an increasingly studied and utilized tool in assessing physiologic and pathologic processes in the field of gynecology. Evaluating tissue stiffness through strain and SWE can serve to improve diagnosis of various uterine and cervical lesions, as well as prognosticate outcomes after fertility treatments. This growing area of research will continue to establish the role and application of ultrasound elastography into clinical practice.

Elasticity of the Cervix in Relation to Uterus Position

Strain elastography allows the evaluation of tissue elasticity. Background/Objectives: Tissue elasticity depends on the content and distribution of collagen fibers and is shaped by the applied tensile forces that may differ in uteri with a different angle of flexion of the corpus on the cervix. The objective was to investigate whether the angle of uterine flexion is related to cervical tissue elasticity. Methods: The anterior angle between the longitudinal axis of the uterus corpus and that of the cervix was measured in 275 non-pregnant young women by transvaginal ultrasonography and considered both as an absolute value or categorized as ≤150°, between >150° and ≤210°, and >210°. Strain elastography was used to assess tissue elasticity by placing the probe in the anterior vaginal fornix. Tissue elasticity was evaluated in the middle of the anterior cervical compartment (ACC), in the middle of the posterior cervical compartment (PCC), in the middle portion of the cervical canal (MCC), and at the internal cervical os (ICO). In a sagittal plane MCC was evaluated across the cervical canal, and ACC and PCC at a distance equal between the cervical canal and the outer anterior or posterior part of the cervix. MCC, ACC and PCC were evaluated at equal distance between the ICO and the external cervical os. Elasticity was expressed as a color score ranging from 0.1 (low elasticity) to 3 (high elasticity). Results: The angle of uterine flexion show a negative linear relation with the elasticity of the ACC (p = 0.001) and MCC (p = 0.002) and a positive relation with the elasticity of the PCC (p = 0.054). In comparison to uteri with an angle of flexion of <150°, those with an angle of flexion of >210° had lower elasticity of the ACC (p = 0.001) and MCC (p = 0.001) and higher elasticity of the PCC (p = 0.004). The ACC/PCC and PCC/MCC elasticity ratios were also significantly different (p = 0.001). Conclusions: The angle of uterine flexion is associated with changes in cervix elasticity. Retroflexion is associated with stiffer ACC and MCC and a more elastic PCC. Differences in tissue elasticity suggest structural changes of the cervix that may have implication in variate obstetric and gynecological conditions.

The use of real time strain endometrial elastosonography plus endometrial thickness and vascularization flow index to predict endometrial receptivity in IVF treatments: a pilot study

BACKGROUND

The usefulness of endometrium strain elastosonography (SE) for the evaluation of endometrial receptivity in women undergoing in vitro fertilization (IVF) remains controversial. The objective of this prospective, observational study was to evaluate the correlation between endometrial thickness (EMT) and its related strain (ESR) on the day of ovulation triggering (hCG-d) and in vitro fertilization outcomes. Additionally, 3D Power Doppler vascular indices (3DPDVI) were also analysed.

METHODS

We included all the patients undergoing fresh IVF-single blastocyst transfer cycle from January 2021 to August 2021 at our center. On hCG-d, after B-mode scanning was completed to measure the EMT, the mode was changed to elastosonography to evaluate the ESR (ratio between endometrial tissue and the myometrium below). At the end of examination, the Endometrial Volume (EV) and 3DPDVI (vascularization index [VI], flow index [FI] and vascularization flow index [VFI]), were assessed. Statistical analysis was completed using STATA MP16 software.

RESULTS

A total number of 57 women were included. Based on the EMT on hCG-d, women were divided into two groups, Group 1: <7 mm and Group 2 ≥ 7 mm. Women with EMT < 7 mm had a significantly higher ESR (p = 0.004) and lower pregnancy rate (p = 0.04). Additionally, low ESR values were correlated with high VFI values (rho = -0.8; 95% CI = -0.9- -0.6; p < 0.0001) and EMT ≥ 7 mm could be predicted by low ESR (OR = 0.01; 95% CI = 0.01-0.30; p = 0.008, area under the ROC curve: 0.70). After all, in multiple logistic regression analysis, low values of ESR (p = 0.050) and high values of EMT (p = 0.051) on hCG-d had borderline statistical effects on pregnancy rate.

CONCLUSIONS

The ESR may be useful to improve the ultrasound evaluation of the endometrial quality in infertile women candidates to IVF/ICS. Given the small sample size of our study, the usefulness of strain elastosonography in this patients, needs further investigation.

Diagnostic accuracy of cervical elastography for predicting preterm delivery: Systematic review and meta-analysis

OBJECTIVE

Cervical elastography has been used in pregnant women to diagnose preterm births. However, there is a variability in the measured elasticity parameters and imaging mode used. We evaluated the precision of cervical elastography in identifying preterm births.

METHODS

Extensive and methodical searches were made in the databases such as Scopus, Embase, Cochrane Library, PubMed Central, Medline, ScienceDirect, and Google Scholar from the inception until November 2022, for studies that report diagnostic accuracy of cervical elastography for preterm deliveries in antenatal women.

RESULTS

The pooled sensitivity and specificity value of cervical elastography for preterm deliveries were 82% (95%CI: 73%-89%) and 77% (95%CI: 64%-86%), respectively with area under curve (AUC) of 0.87 (95%CI: 0.72-0.95). The diagnostic odds ratio (DOR) was 15 (95%CI: 8-28), positive likelihood ratio (LRP) was 3.5 (95%CI: 2.3-5.5) and negative likelihood ratio LRN was 0.23 (0.16-0.34). Pooled sensitivity and specificity of shear wave elastography was 88% and 71%, respectively. Pooled sensitivity and specificity of strain elastography was 80% and 79%, respectively. Heterogeneity was significant, as indicated by chi-square test and an I2 statistic of over 75.

CONCLUSIONS

Cervical elastography can be used for predicting preterm deliveries with moderate to high level of accuracy.

Hysteroscopic cervical features associated with difficult embryo transfer in unselected patients undergoing in vitro fertilization

Background

The most appropriate diagnostic tests for the assessment of the uterine cavity in patients undergoing standard infertility evaluation in daily practice remain unclear. Routine hysteroscopic uterine cavity evaluation before an in vitro fertilization-embyo transfer (IVF-ET) cycle is not a uniformly accepted procedure. However, cervical findings associated with difficult ET have rarely been reported in previous hysteroscopic studies. The main objective of this study was to examine the relationship between cervical finding under flexible outpatient hysteroscopy (OH) and difficult ET.

Methods

A cohort clinical study was conducted with 650 patients undergoing their first in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) from January 2010 to December 2017. Of them, 605 women with available embryos underwent transfer cycles. Outpatient hysteroscopies were scheduled during the follicular phase of the menstrual cycle, 1–3 months before starting IVF/ICSI treatment.

Results

Among the 650 women who underwent transvaginal sonography (TVS) and OH, abnormal sonographic findings were observed in 51 women (7.8%) in which submucous myoma, endometrial polyp, and endometrial hyperplasia were the most common. Abnormal hysteroscopic intracavitary findings were observed in 158 cases (24.3%) in which endometrial polyp, submucous myoma, and intrauterine adhesions were the most common. These results showed that TVS was specific (100%) but not sensitive (32.3%) compared with OH. Embryo transfer (ET) was difficult in 25% of women with cervical stenosis (CS) or tortuous cervical canal (TC) and was significantly more difficult in women in the TC group (30.7%) than in the CS group (19.6%).

Conclusion

OH can identify cervical charactistics associated with a high incidence of difficult ET.

Menstrual Pain and Elasticity of Uterine Cervix

Menstrual pain is consequent to intense uterine contraction aimed to expel menstrual flow through downstream uterine cervix. Herein it was evaluated whether characteristics of uterine cervix are associated with intensity of menstrual pain. Ultrasound elastography was used to analyze cervix elasticity of 75 consecutive outpatient women. Elasticity was related to intensity of menstrual pain defined by a Visual Analogue Scale (VAS). Four regions of interest (ROI) were considered: internal uterine orifice (IUO), anterior (ACC) and posterior cervical (PCC) compartment and middle cervical canal (MCC). Tissue elasticity, evaluated by color score (from 0.5 = blue/violet (low elasticity) to 3.0 = red (high elasticity), and percent tissue deformation was analyzed. Elasticity of IUO was lower (p = 0.0001) than that of MCC or ACC, and it was negatively related (R2 = 0.428; p = 0.0001) to menstrual VAS (CR −2.17; 95%CI −3.80, −0.54; p = 0.01). Presence of adenomyosis (CR 3.24; 95% CI 1.94, 4.54; p = 0.0001) and cervix tenderness at clinical examination (CR 2.74; 95% CI 1.29, 4.20; p = 0.0004), were also independently related to menstrual VAS. At post hoc analysis, women with vs. without menstrual pain had lower IUO elasticity, expressed as color score (0.72 ± 0.40 vs. 0.92 ± 0.42; p = 0.059), lower percent tissue deformation at IUO (0.09 ± 0.05 vs. 0.13 ± 0.08; p = 0.025), a higher prevalence of cervical tenderness at bimanual examination (36.2% vs. 9.5%; p = 0.022) and a higher prevalence of adenomyosis (46.5% vs. 19.9%; p = 0.04). These preliminary data indicate that IUO elasticity is associated with the presence and the intensity of menstrual pain. Mechanisms determining IUO elasticity are useful to be explored.

Ultrasonographic cervical evaluation: A tool to select ewes for non-surgical embryo recovery

This study assessed the cervical ultrasonography mapping as a tool to select donor ewes for non-surgical embryo recovery (NSER). Lacaune ewes had their cervix evaluated by ultrasonography 12 hr after induced oestrus onset (Trial 1, n = 24) or 30 min before NSER (Trial 2, n = 17). Cervical rings were longitudinally evaluated and classified by their degree of misalignment on ultrasonography (DMUS) into: DMUS-1-cervix rectilinear, DMUS-2-intermediate and DMUS-3-highly asymmetrical. For predicting cervical transposing, only DMUS-1 and DMUS-2 were considered suitable. Similar ranking was attributed to degree of misalignment on the cervical map (DMCM 1-3), established immediately before NSER, which was performed at days 6 to 7 after oestrus. In Trial 1, cervical retraction for NSER was not possible only in three ewes classified as DMUS-3 (3/14, 21.4%). No difference (p > .05) was observed in the cervical transposing rates between ewes with different DMUS (ranged from 80% to 100%). In Trial 2, DMUS-1 and DMUS-2 reached 100% of transposing, and the only DMUS-3 ewe has not been transposed. In Trial 1, the prediction performance for successful cervical transposing showed low sensitivity (45%) and no specificity due to a high incidence of false negatives (52%). However, in Trial 2, sensitivity and specificity were both 100%. The DMCM and DMUS were uncorrelated, probably due to cervical stretching required to perform NSER. In conclusion, cervical ultrasound assessment immediately before NSER was more efficient to predict the cervical transposing than at induced oestrus, allowing the classification and selection of ewes eligible for NSER.

Effect of Stifle Flexion Angle on the Repeatability of Real-Time Elastosonography of the Patellar Ligament in Medium- to Large-Breed Dogs

OBJECTIVE

 The aims of this study were to describe the elastosonographic findings of the patellar ligament in healthy dogs >15 kg in different positions and determine the most appropriate stifle angle to perform elastosonography of the patellar ligament.

STUDY DESIGN

 Eighteen clinically healthy dogs, weighing >15 kg, were prospectively recruited. B-mode ultrasound and real-time elastosonography of both patellar ligaments were performed on days 0 and 14. Elastosonography examinations were performed with the stifle in four positions: standing position, lateral recumbency with the stifle positioned at 135 degrees extension and in full passive flexion and extension.

RESULTS

 The percentage hardness of the patellar ligament was significantly lower when the elastosonographic examination was performed with the dog standing, compared with the other positions (p < 0.005). The variability in the elastosonography readings for each stifle position was lowest when the dog was standing (89.32%).

CONCLUSION

 Elastosonography is a feasible technique for evaluating the elasticity of the normal canine patellar ligament in dogs >15 kg and would be a useful technique for investigating the mechanical changes within the patellar ligament following stifle surgery. Elastosonography of the patellar ligament should be performed with the dog standing to provide the most accurate elastosonograms with lowest variability between readings.

Influence of epidemiological characteristics (age, parity and other factors) in the assessment of healthy uterine cervical stiffness evaluated through shear wave elastography as a prior step to its use in uterine cervical pathology

PURPOSE

The purpose of this study was to evaluate stiffness changes occurring in the healthy uterine cervix according to age, parity, phase of the menstrual cycle and other factors by shear wave elastography (SWE).

METHODS

Evaluations of cervical speed and stiffness measurements were performed in 50 non-pregnant patients without gynaecological pathology using SWE transvaginal ultrasound. We performed the evaluation in the midsagittal plane of the uterine cervix with measurements at 0.5, 1 and 1.5 cm from external cervical os, at both anterior and posterior cervical lips.

RESULTS

We evaluated 44 patients by SWE and obtained a total average velocity of 3.48 ± 1.08 m/s and stiffness of 42.39 ± 25.33 kPa. We found differences in speed and stiffness according to the cervical lip and depth evaluated; thus, we observed a velocity of 2.70 m/s at 0.5 cm of depth in the anterior lip and 3.53 m/s at 1.5 cm of depth in the posterior lip (p < 0.05). We observed differences according to parity, obtaining a wave transmission speed of 2.67 m/s and 4.41 m/s at the cervical canal of nulliparous and multiparous patients, respectively (p < 0 0.002). We observed differences according to patient age (from a speed of 2.75 m/s at the cervical canal in the age group of 20-35 years to 5.05 m/s in the age group > 50 years) (p < 0.008). We did not observe differences in speed or stiffness according to the phase of the menstrual cycle, BMI, smoking status or the presence or absence of non-HPV infections.

CONCLUSIONS

The wave transmission speed and stiffness of the uterine cervix evaluated by SWE varies according to the cervical lip and depth of the evaluation as well as according to the parity and age of the patient.

Diagnostic accuracy of cervical elastography in predicting preterm delivery: A systematic review and meta-analysis

BACKGROUND

The aim of the study was to evaluate the diagnostic accuracy of cervical elastography in predicting preterm delivery (PTD).

METHODS

We searched the PubMed, EMBASE, and Cochrane databases to identify relevant studies that applied ultrasound (US) elastography to assess cervical stiffness and predict PTD. All the studies were published before December 11, 2018, and only studies published in English were collected. The cervical length (CL) was considered a comparator, and the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool was applied to assess the quality of the included studies. Summary receiver operating characteristic (SROC) modeling was performed to evaluate the diagnostic performance of cervical elastography in predicting PTD. Subgroup analyses were also performed.

RESULTS

Seven studies, including 1488 pregnant women, were included in this meta-analysis. Cervical elastography showed a summary sensitivity of 0.84 [95% confidence interval (CI): 0.68, 0.93], a specificity of 0.82 (95% CI: 0.63, 0.93), a diagnostic odds ratio of 25 (95% CI: 7, 93), and an area under the curve (AUC) of SROC of 0.90 (95% CI: 0.87-0.93). CL measurement showed that the AUC of SROC was 0.60 (95% CI: 0.56-0.64). The results of subgroup analysis showed that the summary sensitivity and specificity were different in the QUADAS-2 score subgroups.

CONCLUSION

Cervical elastography is a promising and reliable method to predict PTD. Cervical elastography showed better diagnostic performance to predict PTD than CL measurement.

Three-dimensionally-printed models in reproductive surgery: systematic review and clinical applications

INTRODUCTION

3D printing has wide application in medicine while it provides customizability and precision for anatomical model development. Our aims were to perform a systematic review and to explore the use of 3D printing applications on human reproduction and reproductive surgery.

EVIDENCE ACQUISITION

We have performed a systematic review in PubMed database to assess previous publications within 3D printing in human reproduction and gynecology. We have developed 3D models according to patients' magnetic resonance images (MRI). MRI were transformed into DICOM images that originated our 3D virtual models and PolyJet technology was applied for the printing process. We included two infertile patients in reproductive age with surgical indication for hysteroscopy septoplasty and myomectomy.

EVIDENCE SYNTHESIS

Of 1965 studies searched, we excluded 1934 publications based on their titles. Abstracts of 31 remained studies were read, and 24 studies were selected for full-text analysis. We included 11 studies for the systematic review, based on our eligibility criteria. We have designed four 3D models (uterus, ovaries, uterine cervix and uterus with fibroids) that provided enriched information to improve pre-surgical planning, medical training, fertility-sparing surgery, patient comprehension of surgical procedures and assisted reproduction applications.

CONCLUSIONS

3D models for human reproduction are feasible. They might improve assisted reproductive techniques, help in pre-surgical planning for reproductive surgeries, and provide accurate measures of ovarian reserve. Besides, we see future applications in endometrioma research and in the fabrication of devices, such as embryo transfer catheter and a 3D printed embryo.