True Reproducibility of UltraSound Techniques (TRUST): systematic review of reliability studies in obstetrics and gynecology

Adrenal volumes in fetuses delivering prior to 32 weeks' gestation: An MRI pilot study

INTRODUCTION

Spontaneous preterm birth prior to 32 weeks' gestation accounts for 1% of all deliveries and is associated with high rates of morbidity and mortality. A total of 70% are associated with chorioamnionitis which increases the incidence of morbidity, but for which there is no noninvasive antenatal test. Fetal adrenal glands produce cortisol and dehydroepiandosterone-sulphate which upregulate prior to spontaneous preterm birth. Ultrasound suggests that adrenal volumes may increase prior to preterm birth, but studies are limited. This study aimed to: (i) demonstrate reproducibility of magnetic resonance imaging (MRI) derived adrenal volumetry; (ii) derive normal ranges of total adrenal volumes, and adrenal: body volume for normal; (iii) compare with those who have spontaneous very preterm birth; and (iv) correlate with histopathological chorioamnionitis.

MATERIAL AND METHODS

Patients at high risk of preterm birth prior to 32 weeks were prospectively recruited, and included if they did deliver prior to 32 weeks; a control group who delivered an uncomplicated pregnancy at term was also recruited. T2 weighted images of the entire uterus were obtained, and a deformable slice-to-volume method was used to reconstruct the fetal abdomen. Adrenal and body volumes were obtained via manual segmentation, and adrenal: body volume ratios generated. Normal ranges were created using control data. Differences between groups were investigated accounting for the effect of gestation by use of regression analysis. Placental histopathology was reviewed for pregnancies delivering preterm.

RESULTS

A total of 56 controls and 26 cases were included in the analysis. Volumetry was consistent between observers. Adrenal volumes were not higher in the case group (p = 0.2); adrenal: body volume ratios were higher (p = 0.011), persisting in the presence of chorioamnionitis (p = 0.017). A cluster of three pairs of adrenal glands below the fifth centile were noted among the cases all of whom had a protracted period at risk of preterm birth prior to MRI.

CONCLUSIONS

Adrenal: body volume ratios are significantly larger in fetuses who go on to deliver preterm than those delivering at term. Adrenal volumes were not significantly larger, we hypothesize that this could be due to an adrenal atrophy in fetuses with fulminating chorioamnionitis. A straightforward relationship of adrenal size being increased prior to preterm birth should not be assumed.

Evaluation of Non-Compressive Transvaginal Cervical Elastography as a Quantitative Imaging Biomarker in Pregnancy: A Repeatability and Reliability Analysis

OBJECTIVES

Non-compressive strain elastography has been proposed as a novel quantitative imaging biomarker for assessing the structure and function of the cervix. The current study aims to assess the repeatability, and intra- and inter-observer reliability of transvaginal non-compressive cervical strain elastography in a clinical setting.

METHODS

We conducted a dual-phase single-center prospective feasibility study of singleton gestations >16-weeks gestation that required a clinically-indicated transvaginal ultrasound. Each study participant, n = 43 in phase 1 and n = 13 in phase 2, had elastography performed by two trained observers that each performed multiple image acquisitions. We performed a multivariable regression to adjust for changes in clinical characteristics between study phases and calculated the repeatability coefficients, limits of agreement, and intraclass correlations for each quantitative elastography parameter. We compared quantitative elastography parameters to cervical length measurements, acquired from the same images.

RESULTS

The repeatability coefficients and percent limits of agreement were wide for all of the quantitative elastography parameters, demonstrating poor repeatability. Intraclass correlation coefficients were poor-moderate for both intra-observer (0.31-0.77) and inter-observer reliability (0.35-0.77) in both study phases, while cervical length showed excellent reliability with intraclass correlations consistently >0.90.

CONCLUSIONS

Non-compressive transvaginal strain cervical elastography did not demonstrate adequate repeatability or reliability. Our results highlight the importance of rigorously assessing novel quantitative imaging biomarkers before clinical application.

Intra- and interobserver reproducibility of transvaginal ultrasound for the detection and measurement of endometriotic lesions of the bowel

INTRODUCTION

The number and invasion depth of endometriotic bowel lesions, total length of bowel affected by endometriosis, lesion-to-anal verge distance, and extent of pouch of Douglas obliteration are important factors in preoperatively determining risk and complexity of endometriosis surgery. The intra- and interobserver reproducibility of transvaginal ultrasound in the evaluation of many of these parameters has not yet been investigated. Our study aimed to assess the intra- and interobserver reproducibility of transvaginal ultrasound between an experienced and less experienced examiner for all of these parameters.

MATERIAL AND METHODS

This prospective observational cross-sectional study was conducted between July 2019 and November 2020. Fifty consecutive premenopausal women who underwent transvaginal ultrasound examination in our clinic for the first time, were examined by the same two operators during the same attendance. Outcomes of interest were the inter-rater reproducibility of transvaginal ultrasound for detecting the presence, number, depth and size of bowel endometriotic nodules, lesion-to-anal-verge distance, total length of bowel affected, and pouch of Douglas obliteration. The intraobserver reproducibility was assessed for the continuous parameters. Cohen's kappa (κ) statistic, Cohen's weighted kappa (κ), proportions of agreement, intraclass correlation coefficient (ICC) and Bland-Altman limits of agreement were used to assess the reproducibility of the parameters.

RESULTS

The inter-rater agreement and reliability were very good for identifying bowel endometriosis, the number and invasion depth of bowel nodules, determining whether the maximum nodule length was <3 cm, and lesion-to-anal-verge distance <8 cm (proportion of agreement 0.92, 0.94, 0.97, 0.94, 0.96; κ 0.92, 0.91, 0.92, 0.82, 0.89). The inter-rater agreement and reliability were good for assessing pouch of Douglas obliteration (proportion of agreement 0.86, κ 0.80). The intra-rater reliability for the mean nodule diameter (ICC 0.93 and 0.97) and total length of bowel affected (ICC 0.94 and 0.91) were excellent for operators A and B, respectively. The inter-rater reliability for the mean nodule diameter was good (ICC 0.80), and moderate for the total length of bowel affected (ICC 0.70). The Bland-Altman limits of agreement demonstrated clinically acceptable ranges for these two parameters.

CONCLUSIONS

This study demonstrated a high intra- and inter-rater reproducibility of transvaginal ultrasound in the diagnosis of bowel endometriosis and measurement of its various components.

Fetal renal artery blood flow - Normal ranges

INTRODUCTION

The study objectives were to develop standard charts for fetal renal artery blood flow to define normal ranges and to assess the reliability of the measurements.

METHODS

This prospective, longitudinal study reviewed 72 low-risk singleton pregnancies who had serial ultrasound examinations. Pulse wave Doppler was used to obtain the resistivity and pulsatility indices of the fetal renal arteries. Standard charts of the fetal renal arteries were created using mixed effects modelling and the intra- and interobserver reliability for the renal blood flow measurements was analysed.

RESULTS

Standard charts of the normal ranges of the renal artery resistive index (RI) and pulsatility index (PI) of the fetal renal arteries were created. The 3rd, 5th, 10th, 50th, 90th, 95th and 97th centiles were calculated. The intraclass correlation coefficient was acceptable for intraobserver reliability (RI = 0.66, PI = 0.88) and poor for interobserver reliability (RI = 0.11, PI = -0.56).

CONCLUSIONS

These novel charts demonstrate the change of the fetal renal artery blood flow during pregnancy. These may be used in clinical practice to detect variations from these normal ranges and be useful in future studies of kidney function projection.

A decision support system based on radiomics and machine learning to predict the risk of malignancy of ovarian masses from transvaginal ultrasonography and serum CA-125

BACKGROUND

To evaluate the performance of a decision support system (DSS) based on radiomics and machine learning in predicting the risk of malignancy of ovarian masses (OMs) from transvaginal ultrasonography (TUS) and serum CA-125.

METHODS

A total of 274 consecutive patients who underwent TUS (by different examiners and with different ultrasound machines) and surgery, with suspicious OMs and known CA-125 serum level were used to train and test a DSS. The DSS was used to predict the risk of malignancy of these masses (very low versus medium-high risk), based on the US appearance (solid, liquid, or mixed) and radiomic features (morphometry and regional texture features) within the masses, on the shadow presence (yes/no), and on the level of serum CA-125. Reproducibility of results among the examiners, and performance accuracy, sensitivity, specificity, and area under the curve were tested in a real-world clinical setting.

RESULTS

The DSS showed a mean 88% accuracy, 99% sensitivity, and 77% specificity for the 239 patients used for training, cross-validation, and testing, and a mean 91% accuracy, 100% sensitivity, and 80% specificity for the 35 patients used for independent testing.

CONCLUSIONS

This DSS is a promising tool in women diagnosed with OMs at TUS, allowing to predict the individual risk of malignancy, supporting clinical decision making.

The reliability of rehabilitative ultrasound to measure lateral abdominal muscle thickness: A systematic review and meta-analysis

BACKGROUND

Variations in rehabilitative ultrasound imaging (RUSI) protocols may alter lateral abdominal muscle (LAM) thickness measurements. A standardised protocol is required for clinicians to accurately compare LAM thickness changes.

OBJECTIVE

In healthy and lower back pain (LBP) populations, to assess the 1) overall reliability of RUSI to diagnose LAM thickness via meta-analysis, 2) reliability of ultrasound variables to diagnose LAM thickness via systematic review, and 3) propose a RUSI protocol for the LAM using variables associated with excellent reliability (intraclass correlation coefficient [ICC] >0.9).

DESIGN

Systematic review and meta-analysis.

METHOD

Databases were searched from January 2000 for studies reporting the reliability of RUSI on the LAM at rest. Title, abstract and full-text screening were performed. Reference lists of reviews and included full-text articles were scanned for further articles. Study characteristic, ultrasound procedure and reliability data were extracted, and article quality assessed. Data was synthesised using meta-analysis to determine the overall reliability for RUSI in different subgroups; calculation of the mean ICCs and standard error of measurements of protocol variables; and narrative synthesis of protocols to contrast those of differing reliability.

RESULTS

Twenty-seven articles, involving 884 participants were included. Reliability ranged from good-to-excellent (ICC 0.859-0.958) in all subgroups. Protocols ranged in subject selection and position, examiner experience, transducer position with the comprehensiveness of protocol description the main limitation of the reviewed literature. Based on the findings an ultrasound protocol was proposed.

CONCLUSIONS

RUSI variables for the LAM at rest show moderate-to-excellent reliability; future research should explore reliability following the proposed protocol.

Quality control of fetal biometric evaluation and Doppler ultrasound

In recent years quality control in obstetric ultrasound has become recommended and an essential component of obstetric scanning. This is to minimize the inaccuracy and variability related to fetal measurements, to provide an effective quality assurance system to sonographers to certify their practice and decrease the impact of medical litigations. For a quality control system in obstetric ultrasound to be useful clinically, multiple strategies need to be employed: certified training, practical standardization exercise, image storing, qualitative and quantitative quality control. Qualitative quality control consists of the evaluation of images obtained for fetal biometry and Doppler scans using an objective score against predefined criteria. Quantitative quality control consists of analyzing quantitatively the performance of a sonographer and the impact on measurements values. Quantitative analysis could be performed either using estimates of intraobserver or interobserver reproducibility of plane acquisition and caliper placements.

Ultrasound diagnosis of endometrial cancer by subjective pattern recognition in women with postmenopausal bleeding: prospective inter-rater agreement and reliability study

OBJECTIVES

To assess the inter-rater agreement and reliability of using subjective pattern recognition for diagnosing endometrial cancer (EC) on ultrasound in women with postmenopausal bleeding (PMB).

METHODS

This was a prospective cross-sectional study conducted at a gynecological rapid-access clinic, between October 2016 and December 2017, in which consecutive women with PMB and endometrial thickness of ≥ 4.5 mm on transvaginal ultrasound examination were included. Women on hormone replacement therapy or tamoxifen and those with a history of primary gynecological malignancy were excluded. Two raters independently performed ultrasound examinations, blinded to each other's findings, and classified women as having uniformly thickened endometrium, benign endometrial polyp or EC, using subjective pattern recognition. Inter-rater reliability of ultrasound diagnosis was assessed using Cohen's kappa (κ) statistic. All women subsequently underwent either outpatient endometrial biopsy, hysteroscopy or hysterectomy.

RESULTS

Forty women were included in the study, with a median age of 61 (interquartile range (IQR), 57-69) years and a median endometrial thickness of 11.0 (IQR, 6.2-20.3) mm. Final histological analysis confirmed 16 (40%) women with EC, 16 (40%) with benign endometrial polyp, four (10%) with atrophic endometrium, three (8%) with proliferative endometrium and one (3%) with endometrial hyperplasia. Inter-rater agreement for the ultrasound diagnoses of uniformly thickened endometrium, benign endometrial polyp and EC was 14/16 (87.5%), 22/30 (73.3%) and 28/34 (82.4%), respectively; inter-rater reliability was good (κ = 0.69; 95% CI, 0.49-0.88). When the ultrasound diagnoses were grouped as either cancer or no cancer, inter-rater agreement was 85% and inter-rater reliability was good (κ = 0.78; 95% CI, 0.61-0.95). Rater A correctly identified 14/16 cases of EC and Rater B identified 15/16. EC was misdiagnosed as benign polyps on ultrasound in two women by Rater A and in one woman by Rater B. The overall accuracies of Rater A and Rater B in differentiating between benign endometrial pathologies and malignancy were 90% and 90%, respectively.

CONCLUSIONS

Our results show good inter-rater reliability of subjective pattern recognition in diagnosing uniformly thickened endometrium, benign endometrial polyp and EC on ultrasound in women with PMB. Our findings should facilitate wider use of subjective pattern recognition in routine clinical practice. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

MRI-Derived Fetal Weight Estimation in the Midpregnancy Fetus: A Method Comparison Study

OBJECTIVES

The aim of this study was to compare the standard ultrasound (US) estimated fetal weight (EFW) and MRI volume-derived methods for the midtrimester fetus.

METHODS

Twenty-five paired US and MRI scans had the EFW calculated (gestational age [GA] range = 20-26 weeks). The intra- and interobserver variability of each method was assessed (2 operators/modality). A small sub-analysis was performed on 5 fetuses who were delivered preterm (mean GA 29 +3 weeks) and compared to the actual birthweight.

RESULTS

Two MRI volumetry EFW formulae under-measured compared to US by -10.9% and -14.5% in the midpregnancy fetus (p < 0.001) but had excellent intra- and interobserver agreement (intraclass correlation coefficient = 0.998 and 0.993). In the preterm fetus, the mean relative difference (MRD) between the MRI volume-derived EFW (MRI-EFW) and actual expected birthweight (at the scan GA) was -13.7% (-159.0 g, 95% CI: -341.7 to 23.7 g) and -17.1% (-204.6 g, 95% CI: -380.4 to -28.8 g), for the 2 MRI formulae. The MRD was smaller for US at 5.3% (69.8 g, 95% CI: -34.3 to 173.9).

CONCLUSIONS

MRI-EFW results should be interpreted with caution in midpregnancy. Despite excellent observer agreement with MRI volumetry, refinement of the EFW formula is needed in the second trimester, for the small and for the GA and preterm fetus to compensate for lower fetal densities.

Quality assessment of fetal middle cerebral and umbilical artery Doppler images using an objective scale within an international randomized controlled trial

OBJECTIVES

To determine the quality of Doppler images of the fetal middle cerebral artery (MCA) and umbilical artery (UA) using an objective scale, and to determine the reliability of this scale, within a multicenter randomized controlled trial (Revealed versus concealed criteria for placental insufficiency in unselected obstetric population in late pregnancy (Ratio37)).

METHODS

The Ratio37 trial is an ongoing randomized, open-label, multicenter controlled study of women with a low-risk pregnancy recruited at 20 weeks. Doppler measurements of the fetal MCA and UA were performed at 37 weeks. Twenty patients from each of the six participating centers were selected randomly, with two images evaluated per patient (one each for the MCA and UA). The quality of a total of 240 images was evaluated by six experts, scored on an objective scale of six items. Inter- and intrarater reliability was assessed using the Fleiss-modified kappa statistic for ordinal scales.

RESULTS

On average, 89.2% of MCA images and 85.0% of UA images were rated as being of perfect (score of 6) or almost perfect (score of 5) quality. Kappa values for intrarater reliability of quality assessment were 0.90 (95% CI, 0.88-0.92) and 0.90 (95% CI, 0.88-0.93) for the MCA and UA, respectively. The corresponding inter-rater reliability values were 0.85 (95% CI, 0.81-0.89) and 0.84 (95% CI, 0.80-0.89), respectively.

CONCLUSION

The quality of MCA and UA Doppler ultrasound images can be evaluated reliably using an objective scale. Over 85% of images, which were obtained by operators from a broad range of clinical practices within a multicenter study, were rated as being of perfect or almost perfect quality. Intra- and inter-rater reliability of quality assessment was very good. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Prospective assessment of reproducibility of three-dimensional ultrasound for fetal biometry

PURPOSE

To compare fetal ultrasound measurements performed by two observers with different levels of experience and evaluate the potential contribution of the use of three-dimensional (3D) ultrasound on repeatability, reproducibility and agreement of two-dimensional (2D) and 3D-derived measurements.

MATERIALS AND METHODS

Two observers (one senior and one junior) measured head circumference (HC), abdominal circumference (AC) and femur length (FL) in 33 fetuses (20 to 40 weeks of gestation). Each observer performed two series of 2D measurements and two series of 3D measurements (i.e., measurements derived from triplane volume processing). Measurements were converted into Z-scores according to gestational age. Variability between the different series of measurements was studied using Bland-Altmann plots and intra-class correlation coefficients (ICC).

RESULTS

Agreement with the 2D measurements of the senior observer was higher in 3D than in 2D for the junior observer (systematic differences of -0.4, -0.2 and -0.8 Z-score vs. -0.1, -0.1 and -0.6 for HC, AC and FL on 2D and 3D datasets, respectively). The use of 3D ultrasound improved junior observer repeatability (ICC=0.94, 0.88, 0.90 vs. 0.94, 0.94 and 0.96 for HC, AC and FL in 2D and 3D, respectively). The reproducibility was greater using the junior observer 3D datasets (ICC=0.75, 0.60 and 0.45 vs. 0.79, 0.89 and 0.63 for HC, AC and FL, respectively).

CONCLUSION

The use of 3D ultrasound improves the consistency of the measurements performed by a junior observer and increases the overall repeatability and reproducibility of measurements performed by observers with different levels of experience.

Optimization of Fetal Biometry With 3D Ultrasound and Image Recognition (EPICEA): protocol for a prospective cross-sectional study

CONTEXT

Variability in 2D ultrasound (US) is related to the acquisition of planes of reference and the positioning of callipers and could be reduced in combining US volume acquisitions and anatomical structures recognition.

OBJECTIVES

The primary objective is to assess the consistency between 3D measurements (automated and manual) extracted from a fetal US volume with standard 2D US measurements (I). Secondary objectives are to evaluate the feasibility of the use of software to obtain automated measurements of the fetal head, abdomen and femur from US acquisitions (II) and to assess the impact of automation on intraobserver and interobserver reproducibility (III).

METHODS AND ANALYSIS

225 fetuses will be measured at 16-30 weeks of gestation. For each fetus, six volumes (two for head, abdomen and thigh, respectively) will be prospectively acquired after performing standard 2D biometry measurements (head and abdominal circumference, femoral length). Each volume will be processed later by both a software and an operator to extract the reference planes and to perform the corresponding measurements. The different sets of measurements will be compared using Bland-Altman plots to assess the agreement between the different processes (I). The feasibility of using the software in clinical practice will be assessed through the failure rate of processing and the score of quality of measurements (II). Interclass correlation coefficients will be used to evaluate the intraobserver and interobserver reproducibility (III).

ETHICS AND DISSEMINATION

The study and related consent forms were approved by an institutional review board (CPP SUD-EST 3) on 2 October 2018, under reference number 2018-033 B. The study has been registered in https://clinicaltrials.gov registry on 23 January 2019, under the number NCT03812471. This study will enable an improved understanding and dissemination of the potential benefits of 3D automated measurements and is a prerequisite for the design of intention to treat randomised studies assessing their impact.

TRIAL REGISTRATION NUMBER

NCT03812471; Pre-results.

The effect of melatonin on ultrasound markers of follicular development: A double-blind placebo-controlled randomised trial

BACKGROUND

Melatonin is a potent oxygen scavenger and is capable of altering blood flow in various vascular beds.

AIMS

We aimed to determine the effect of melatonin on ovarian vascular indices during ovarian stimulation for in vitro fertilisation (IVF).

MATERIALS AND METHODS

This is a pilot double-blind placebo-controlled randomised trial. Sixty-nine women (mean age 35.8 ± 4.3 years) undergoing their first cycle of IVF were randomised to receive either placebo, 2, 4 or 8 mg of melatonin, twice a day. Each participant underwent a transvaginal ultrasound at days 6-10 assessing follicular number and size. The vascularisation index (VI), flow index (FI) and vascularisation-flow index (VFI) were measured. These indices were then correlated with embryological outcomes. Informed consent was obtained from participants. This trial was registered with the Australia New Zealand Clinical Trials Registry (ACTRN12613001317785).

RESULTS

The number of follicles did not differ between groups (P = 0.4). There were no differences in the VI (P = 0.4), FI (P = 0.1) or VFI (P = 0.3) in the right ovary or the FI (P = 0.3) or VFI (P = 0.3) in the left ovary between groups. When comparing placebo to any dose of melatonin, there were no differences in any measured parameter. While there was correlation between the number of follicles on ultrasound and all measured embryological outcomes, there was no correlation between ovarian vascular indices and these important clinical outcomes.

CONCLUSIONS

Melatonin does not appear to change ovarian vascular indices during ovarian stimulation. In addition, such vascular indices cannot predict the number or quality of oocytes or embryos obtained in an IVF cycle. These findings require confirmation in future larger studies.

Intra- and Inter-Rater Agreement Describing Myometrial Lesions Using Morphologic Uterus Sonographic Assessment: A Pilot Study

OBJECTIVES

To evaluate the intra- and inter-rater agreement for myometrial lesions using Morphologic Uterus Sonographic Assessment terminology.

METHODS

Thirteen raters with high (n = 6) or medium experience (n = 7) assessed 30 3-dimensional ultrasound clips with (n = 20) and without (n = 10) benign myometrial lesions. Myometrial lesions were reported as poorly or well defined and then systematically evaluated for the presence of individual features. The clips were blindly assessed twice (at a 2-month interval). Intra- and inter-rater agreements were calculated with κ statistics.

RESULTS

The reporting of poorly defined lesions reached moderate intra-rater agreement (κ = 0.49 [high experience] and 0.47 [medium experience]) and poor inter-rater agreement (κ = 0.39 [high experience] and 0.25 [medium experience]). The reporting of well-defined lesions reached good to very good intra-rater agreement (κ = 0.73 [high experience] and 0.82 [medium experience]) and good inter-rater agreement (κ = 0.75 [high experience] and 0.63 [medium experience]). Most individual features associated with ill-defined lesions reached moderate intra- and inter-rater agreement among highly experienced raters (κ = 0.41-0.60). The least reproducible features were myometrial cysts, hyperechoic islands, subendometrial lines and buds, and translesional flow (κ = 0.11-0.34). Most individual features associated with well-defined lesions reached moderate to good intra- and inter-rater agreement among all observers (κ = 0.41-0.80). The least reproducible features were a serosal contour, asymmetry, a hyperechoic rim, and fan-shaped shadows (κ = 0.00-0.35).

CONCLUSIONS

The reporting of well-defined lesions showed excellent agreement, whereas the agreement for poorly defined lesions was low, even among highly experienced raters. The agreement on identifying individual features varied, especially for features associated with ill-defined lesions. Guidelines on minimum requirements for features associated with ill-defined lesions to be interpreted as poorly defined lesions may improve agreement.

Intra- and Interobserver Reproducibility of Third Trimester Middle Cerebral Artery Pulsatility Index Measurement: A Prospective Cross-Sectional Study

BACKGROUND

Middle cerebral artery (MCA) pulsatility index (PI) Doppler in the third trimester of pregnancy is increasingly used.

OBJECTIVES

The aim of the study was to investigate intra- and interobserver reproducibility of MCA PI in the third trimester.

METHOD

Singleton pregnancies between 30+0 and 40+0 weeks were recruited. MCA Doppler velocimetry measurements were performed prospectively, independently, and blindly. Intra- and interobserver reproducibility was assessed by concordance correlation coefficient (CCC) and intraclass correlation coefficient (ICC); Bland-Altman plots were built, and limits of agreement (LoA) were calculated. Results were interpreted according to the cutoff set by the True Reproducibility of Ultrasound Techniques Review.

RESULTS

We enrolled 101 patients. ICCs for intraobserver reproducibility were 0.84 and 0.78 for raw values and percentiles, respectively; CCCs were 0.72 and 0.64. For interobserver reproducibility ICCs were 0.84 and 0.78, CCCs 0.72 and 0.63. According to the chosen criteria, these values show a poor-moderate reproducibility of third trimester MCA PI. Cohen's Kappa coefficients were 0.59 and 0.42, indicating a moderate agreement in discriminating normal and abnormal values.

CONCLUSIONS

Intra- and interobserver reproducibility of third trimester MCA PI, as assessed by ICC, CCC, and LoA, is far from satisfactory. This should be taken into account before taking clinical decisions.

Inter-rater agreement in the diagnosis of adenomyosis by 2- and 3-dimensional transvaginal ultrasonography

OBJECTIVES

To assess the inter-rater agreement of 2-dimensional (2D) and 3-dimensional (3D) transvaginal ultrasonography (TVUS) in the diagnosis of adenomyosis.

METHODS

This prospective study included premenopausal women (n = 96) with heavy menstrual bleeding, menstrual pain, or both who were scheduled for hysterectomy or transcervical resection of the endometrium. All women underwent real-time 2D TVUS and subsequently offline 3D TVUS, which was blinded to 2D TVUS, by a single expert rater and a single nonexpert rater for the diagnosis of adenomyosis based on standardized pattern recognition and junctional zone measurements. Three-dimensional TVUS was done on a computer with 3D volumes recorded during 2D TVUS by both raters. The expert rater reported the image quality of all 3D volumes (n = 192). Inter-rater agreement (Cohen's κ) was assessed for both techniques, and the improvement over time was assessed for 2D TVUS.

RESULTS

Diagnosis of adenomyosis showed good (κ = 0.69) and poor (κ = 0.21) inter-rater agreement with 2D and 3D TVUS, respectively (P < .05). The agreement with 2D TVUS improved over time. The agreement with 3D TVUS was slightly better for expert-recorded 3D volumes (κ = 0.40), which also had better image quality (P < .05). The most reproducible 2D and 3D features were anechoic lacunae (κ = 0.52) and junctional zone irregularity (κ = 0.27), respectively.

CONCLUSIONS

Standardized pattern recognition during real-time 2D TVUS may result in good agreement between expert and nonexpert raters for the diagnosis of adenomyosis. Offline 3D TVUS is less reproducible, and junctional zone measurements do not improve the inter-rater agreement. The low inter-rater agreement may be related to a lack of experience and low image quality of nonexpert-recorded 3D volumes.

Prediction of Tubal Ectopic Pregnancy Using Offline Analysis of 3-Dimensional Transvaginal Ultrasonographic Data Sets: An Interobserver and Diagnostic Accuracy Study

OBJECTIVES

To assess interobserver reproducibility in detecting tubal ectopic pregnancies by reading data sets from 3-dimensional (3D) transvaginal ultrasonography (TVUS) and comparing it with real-time 2-dimensional (2D) TVUS.

METHODS

Images were initially classified as showing pregnancies of unknown location or tubal ectopic pregnancies on real time 2D TVUS by an experienced sonologist, who acquired 5 3D volumes. Data sets were analyzed offline by 5 observers who had to classify each case as ectopic pregnancy or pregnancy of unknown location. The interobserver reproducibility was evaluated by the Fleiss κ statistic. The performance of each observer in predicting ectopic pregnancies was compared to that of the experienced sonologist. Women were followed until they were reclassified as follows: (1) failed pregnancy of unknown location; (2) intrauterine pregnancy; (3) ectopic pregnancy; or (4) persistent pregnancy of unknown location.

RESULTS

Sixty-one women were included. The agreement between reading offline 3D data sets and the first real-time 2D TVUS was very good (80%-82%; κ = 0.89). The overall interobserver agreement among observers reading offline 3D data sets was moderate (κ = 0.52). The diagnostic performance of experienced observers reading offline 3D data sets had accuracy of 78.3% to 85.0%, sensitivity of 66.7% to 81.3%, specificity of 79.5% to 88.4%, positive predictive value of 57.1% to 72.2%, and negative predictive value of 87.5% to 91.3%, compared to the experienced sonologist's real-time 2D TVUS: accuracy of 94.5%, sensitivity of 94.4%, specificity of 94.5%, positive predictive value of 85.0%, and negative predictive value of 98.1%.

CONCLUSIONS

The diagnostic accuracy of 3D TVUS by reading offline data sets for predicting ectopic pregnancies is dependent on experience. Reading only static 3D data sets without clinical information does not match the diagnostic performance of real time 2D TVUS combined with clinical information obtained during the scan.

International Endometrial Tumor Analysis (IETA) terminology in women with postmenopausal bleeding and sonographic endometrial thickness ≥ 4.5 mm: agreement and reliability study

OBJECTIVE

To estimate intra- and interrater agreement and reliability with regard to describing ultrasound images of the endometrium using the International Endometrial Tumor Analysis (IETA) terminology.

METHODS

Four expert and four non-expert raters assessed videoclips of transvaginal ultrasound examinations of the endometrium obtained from 99 women with postmenopausal bleeding and sonographic endometrial thickness ≥ 4.5 mm but without fluid in the uterine cavity. The following features were rated: endometrial echogenicity, endometrial midline, bright edge, endometrial-myometrial junction, color score, vascular pattern, irregularly branching vessels and color splashes. The color content of the endometrial scan was estimated using a visual analog scale graded from 0 to 100. To estimate intrarater agreement and reliability, the same videoclips were assessed twice with a minimum of 2 months' interval. The raters were blinded to their own results and to those of the other raters.

RESULTS

Interrater differences in the described prevalence of most IETA variables were substantial, and some variable categories were observed rarely. Specific agreement was poor for variables with many categories. For binary variables, specific agreement was better for absence than for presence of a category. For variables with more than two outcome categories, specific agreement for expert and non-expert raters was best for not-defined endometrial midline (93% and 96%), regular endometrial-myometrial junction (72% and 70%) and three-layer endometrial pattern (67% and 56%). The grayscale ultrasound variable with the best reliability was uniform vs non-uniform echogenicity (multirater kappa (κ), 0.55 for expert and 0.52 for non-expert raters), and the variables with the lowest reliability were appearance of the endometrial-myometrial junction (κ, 0.25 and 0.16) and the nine-category endometrial echogenicity variable (κ, 0.29 and 0.28). The most reliable color Doppler variable was color score (mean weighted κ, 0.77 and 0.69). Intra- and interrater agreement and reliability were similar for experts and non-experts.

CONCLUSIONS

Inter- and intrarater agreement and reliability when using IETA terminology were limited. This may have implications when assessing the association between a particular ultrasound feature and a specific histological diagnosis, because lack of reproducibility reduces the reliability of the association between a feature and the outcome. Future studies should investigate whether using fewer categories of variable or offering practical training could improve agreement and reliability. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

A comparison of ultrasound with magnetic resonance imaging in the assessment of fetal biometry and weight in the second trimester of pregnancy: An observer agreement and variability study

Objective

To compare the intra and interobserver variability of ultrasound and magnetic resonance imaging in the assessment of common fetal biometry and estimated fetal weight in the second trimester.

Methods

Retrospective measurements on preselected image planes were performed independently by two pairs of observers for contemporaneous ultrasound and magnetic resonance imaging studies of the same fetus. Four common fetal measurements (biparietal diameter, head circumference, abdominal circumference and femur length) and an estimated fetal weight were analysed for 44 'low risk' cases. Comparisons included, intra-class correlation coefficients, systematic error in the mean differences and the random error.

Results

The ultrasound inter- and intraobserver agreements for ultrasound were good, except intraobserver abdominal circumference (intra-class correlation coefficient = 0.880, poor), significant increases in error was seen with larger abdominal circumference sizes. Magnetic resonance imaging produced good/excellent intraobserver agreement with higher intra-class correlation coefficients than ultrasound. Good interobserver agreement was found for both modalities except for the biparietal diameter (magnetic resonance imaging intra-class correlation coefficient = 0.942, moderate). Systematic errors between modalities were seen for the biparietal diameter, femur length and estimated fetal weight (mean percentage error = +2.5%, -5.4% and -8.7%, respectively, p < 0.05). Random error was above 5% for ultrasound intraobserver abdominal circumference, femur length and estimated fetal weight and magnetic resonance imaging interobserver biparietal diameter, abdominal circumference, femur length and estimated fetal weight (magnetic resonance imaging estimated fetal weight error >10%).

Conclusion

Ultrasound remains the modality of choice when estimating fetal weight, however with increasing application of fetal magnetic resonance imaging a method of assessing fetal weight is desirable. Both methods are subject to random error and operator dependence. Assessment of calliper placement variations may be an objective method detecting larger than expected errors in fetal measurements.

Congenital Uterine Malformation by Experts (CUME): better criteria for distinguishing between normal/arcuate and septate uterus?

OBJECTIVES

To assess the level of agreement between experts in distinguishing between septate and normal/arcuate uterus using their subjective judgment when reviewing the coronal view of the uterus from three-dimensional ultrasound. Another aim was to determine the interobserver reliability and diagnostic test accuracy of three measurements suggested by recent guidelines, using as reference standard the decision made most often by experts (Congenital Uterine Malformation by Experts (CUME)).

METHODS

Images of the coronal plane of the uterus from 100 women with suspected fundal internal indentation were anonymized and provided to 15 experts (five clinicians, five surgeons and five sonologists). They were instructed to indicate whether they believed the uterus to be normal/arcuate (defined as normal uterine morphology or not clinically relevant degree of distortion caused by internal indentation) or septate (clinically relevant degree of distortion caused by internal indentation). Two other observers independently measured indentation depth, indentation angle and indentation-to-wall-thickness (I:WT) ratio. The agreement between experts was assessed using kappa, the interobserver reliability was assessed using the concordance correlation coefficient (CCC), the diagnostic test accuracy was assessed using the area under the receiver-operating characteristics curve (AUC) and the best cut-off value was assessed using Youden's index, considering as the reference standard the choice made most often by the experts (CUME).

RESULTS

There was good agreement between all experts (kappa, 0.62). There were 18 septate and 82 normal/arcuate uteri according to CUME; European Society of Human Reproduction and Embryology (ESHRE)-European Society for Gynaecological Endoscopy (ESGE) criteria (I:WT ratio > 50%) defined 80 septate and 20 normal/arcuate uteri, while American Society for Reproductive Medicine (ASRM) criteria defined five septate (depth > 15 mm and angle < 90°), 82 normal/arcuate (depth < 10 mm and angle > 90°) and 13 uteri that could not be classified (referred to as the gray-zone). The agreement between ESHRE-ESGE and CUME was 38% (kappa, 0.1); the agreement between ASRM criteria and CUME for septate was 87% (kappa, 0.39), and considering both septate and gray-zone as septate, the agreement was 98% (kappa, 0.93). Among the three measurements, the interobserver reproducibility of indentation depth (CCC, 0.99; 95% CI, 0.98-0.99) was better than both indentation angle (CCC, 0.96; 95% CI, 0.94-0.97) and I:WT ratio (CCC, 0.92; 95% CI, 0.90-0.94). The diagnostic test accuracy of these three measurements using CUME as reference standard was very good, with AUC between 0.96 and 1.00. The best cut-off values for these measurements to define septate uterus were: indentation depth ≥ 10 mm, indentation angle < 140° and I:WT ratio > 110% .

CONCLUSIONS

The suggested ESHRE-ESGE cut-off value overestimates the prevalence of septate uterus while that of ASRM underestimates this prevalence, leaving in the gray-zone most of the uteri that experts considered as septate. We recommend considering indentation depth ≥ 10 mm as septate, since the measurement is simple and reliable and this criterion is in agreement with expert opinion. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Beat-to-beat variability of fetal myocardial performance index

OBJECTIVES

To determine whether there is beat-to-beat (BTB) variability in the fetal left myocardial performance index (MPI), as evaluated by an automated system, and whether there is a correlation between MPI and fetal heart rate (FHR).

METHODS

This was a prospective cross-sectional study of uncomplicated, morphologically normal, singleton pregnancies at 20-38 weeks' gestation. Multiple cineloops for left MPI measurement were acquired during a single examination of each fetus. Raw cineloop data were analyzed by our automated MPI system (intraclass correlation coefficient of 1.0 for any given waveform) to produce a set of MPIs. The corresponding instantaneous FHR was measured for each individual cardiac cycle for which MPI was calculated.

RESULTS

Data from 29 fetuses were analyzed; mean MPI was 0.52, mean FHR was 150 beats per min and the median number of cardiac cycles examined per fetus was 70 (interquartile range, 31-115). Marked BTB variability was noted; median coefficient of variation was 10% (range, 5.5-13.9%). FHR was weakly correlated with absolute MPI (r = 0.22; P < 0.05). BTB variation in MPI as a percentage of the mean MPI was not significantly correlated with FHR (r = 0.031; P = 0.146). When standard error of the mean of all MPI values was divided by the mean for each case, it showed that at least four cardiac cycles should be averaged to reduce MPI variability to approximately ± 5%.

CONCLUSION

There is significant BTB variability in fetal left MPI, which has an overall weak correlation with FHR. This could be a factor affecting the consistency of MPI values reported by different research groups. Variability would be reduced by averaging 4-5 cardiac cycles per fetus. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Intraexaminer and Interexaminer Variability in 3D Fetal Volume Measurements During the Second and Third Trimesters of Pregnancy

OBJECTIVES

To assess intraexaminer and interexaminer reliability of 3-dimensional fetal sonographic measurements.

METHODS

Three-dimensional fetal organ volumes (head, kidney, total thigh volume, and fractional thigh volume) were acquired during the second and third trimesters, with the addition of placental volume in the second trimester, by 2 different experienced, blinded sonographers. Fifty-eight fetuses were examined from 21 to 39 weeks' gestation. Intraexaminer and Interexaminer reliability was assessed with Bland-Altman plots, and their 95% limits of agreement and intraclass correlation coefficients.

RESULTS

The most significant interexaminer error was observed in the second-trimester kidney volume (95% limits of agreement, ± 110%), and the best agreement was for the third-trimester fractional thigh volume (95% limits of agreement, ± 25%) and second-trimester head volume (95% limits of agreement, -7%-25%). Second- and third-trimester intraclass correlation coefficient results were all greater than 0.75, apart from second-trimester kidney volume intraexaminer (0.374) and interexaminer (0.061) measurements, second-trimester placenta interexaminer measurements (0.390), and third-trimester kidney interexaminer measurements (0.647).

CONCLUSIONS

Three-dimensional fetal sonographic volumes of the head, kidney, total thigh, and placenta have limited reproducibility, and improvements in measurement techniques are needed before they can be used routinely to assess fetal growth. The 3-dimensional fractional thigh volume can be reliably obtained in the late third trimester.

Performance of ultrasound-based endometriosis staging system (UBESS) for predicting level of complexity of laparoscopic surgery for endometriosis

OBJECTIVE

To develop and assess the performance of a preoperative ultrasound-based endometriosis staging system (UBESS) to predict the level of complexity of laparoscopic surgery for endometriosis.

METHODS

This was a multicenter prospective and retrospective cohort study on consecutive women with suspected endometriosis who underwent laparoscopy between June 2009 and July 2013. Each woman underwent a systematic transvaginal ultrasound evaluation to assess the pelvis for different phenotypes of endometriosis, and the diagnostic performance of ultrasound for these different phenotypes was evaluated relative to the gold standard, laparoscopy. A three-stage preoperative UBESS was developed to assess the severity of pelvic endometriosis, based on the histological phenotypes of endometriosis, the anatomical locations of deep infiltrating endometriosis and their sonographic markers of local invasiveness. The three stages of UBESS (I-III) were then correlated with the three levels of complexity of laparoscopic surgery for endometriosis described by the Royal College of Obstetricians and Gynaecologists (Levels 1-3). The end-points were the diagnostic performance of UBESS to predict the level of complexity of laparoscopic surgery for endometriosis, i.e. UBESS stage I to predict Level-1 laparoscopic surgery, UBESS stage II to predict Level-2 laparoscopic surgery and UBESS stage III to predict Level-3 laparoscopic surgery.

RESULTS

The analysis included 192 women, with a mean ± SD age at diagnosis of endometriosis of 23.7 ± 9.3 years and a mean duration of symptoms prior to presentation of 42 months. Predominant reported locations of pelvic pain were left iliac fossa (32%), right iliac fossa (29.5%) and lower abdomen (61%) and predominant symptoms included dyspareunia (57.5%), dysmenorrhea (58.5%) and dyschezia (41.5%). The accuracy, sensitivity, specificity, positive and negative predictive values and positive and negative likelihood ratios of UBESS I for predicting a requirement for Level-1 laparoscopic surgery were: 87.5%, 83.3%, 91.7%, 90.9%, 84.6%, 10 and 0.182; those of UBESS II for predicting Level-2 surgery were: 87.0%, 73.7%, 90.3%, 65.1%, 93.3%, 7.6 and 0.292; and those of UBESS III for predicting Level-3 surgery were: 95.3%, 94.8%, 95.5%, 90.2%, 97.7%, 21.2 and 0.054, respectively.

CONCLUSION

UBESS could be utilized to predict the level of complexity of laparoscopic surgery for endometriosis. It has the potential to facilitate the triage of women with suspected endometriosis to the most appropriate surgical expertise required for laparoscopic endometriosis surgery. UBESS needs to be validated externally in multiple centers to assess its general applicability. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Evaluation of an automated fetal myocardial performance index

OBJECTIVE

To compare automated measurements of the fetal left myocardial performance index (MPI) with manual measurements for absolute value, repeatability and waveform acceptability.

METHODS

This was a multicenter international online study using images from uncomplicated, morphologically normal singleton pregnancies (16-38 weeks' gestation). Single Doppler ultrasound cardiac cycle images of 25 cases were selected, triplicated and randomized (n = 75). Six senior observers, unaware of the repetition of images, manually calculated MPI for each waveform and the results were compared with automation. Intraobserver repeatability and interobserver reproducibility were assessed using intraclass correlation coefficients (ICCs) and 95% CI. The agreement between each observer's manual MPI measurements and corresponding automated measurements was evaluated using Bland-Altman plots and ICCs with 95% CI. The degree of variation between experts in the classification of fetal MPI waveform quality was assessed using individual cardiac cycle left MPI images previously classified by two authors as 'optimal', 'suboptimal' or 'unacceptable', with 30 images selected for each quality group. Ten images in each category were duplicated and the resulting 120 images were randomized and then classified online by five observers. The kappa statistic (κ) was used to demonstrate interobserver and intraobserver agreement and agreement of classifications by the five observers.

RESULTS

The automated measurement software returned the same value for any given image, resulting in an ICC of 1.00. Manual measurements had intraobserver repeatability ICC values ranging from 0.69 to 0.97, and the interobserver reproducibility ICC was 0.78. Comparison of automated vs manual MPI absolute measurements for each observer gave ICCs ranging from 0.77 to 0.96. Interobserver image quality classification agreement gave k = 0.69 (P < 0.001), and the intraobserver agreement was variable (κ ranging from 0.40 to 0.81).

CONCLUSIONS

Automated fetal MPI provides superior repeatability and reproducibility to manual methodology. Additionally, experts vary significantly when classifying suitability of fetal MPI waveforms. Automated MPI may facilitate clinical translation by removing human subjectivity. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

WITHDRAWN: Response from original author: Reproducibility of first trimester three-dimensional placental measurements; a methodological issue

The Publisher regrets that this article is an accidental duplication of an article that has already been published, DOI of original article: http://dx.doi.org/10.1016/j.ejogrb.2016.07.485. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Ultrasound Quality Assurance for Singletons in the National Institute of Child Health and Human Development Fetal Growth Studies

OBJECTIVES

To report on the ultrasound quality assurance program for the National Institute of Child Health and Human Development Fetal Growth Studies and describe both its advantages and generalizability.

METHODS

After training on an ultrasound system and software, research sonographers were expected to capture blank (unmeasured) images in triplicate for crown-rump length, biparietal diameter, head circumference, abdominal circumference, and femur length. A primary expert sonographer was designated and validated. A 5% sample (n = 740 of 14,785 scans) was randomly selected in 3 distinct rounds from within strata of maternal body mass index (round 1 only), gestational age, and research site. Unmeasured images were extracted from selected scans and measured with the ultrasound software by an expert sonographer. Correlations and coefficients of variation (CVs) were calculated, and the within-measurement standard deviation (ie, technical error of the measurement), was calculated.

RESULTS

The reliability between the site sonographers and the expert was high, with correlations exceeding 0.99 for all dimensions in all rounds. The CV % values showed low variability, with the percentage differences being less than 2%, except for abdominal circumference in rounds 2 and 3, in which it averaged about 3%. Correlations remained high (>0.90) with increasing fetal size; there was a monotonic increase in technical errors of the measurement but without a corresponding increase in the CV %.

CONCLUSIONS

Using rigorous procedures for training sonographers, coupled with quality assurance oversight, we determined that the measurements acquired longitudinally for singletons are both accurate and reliable for establishment of an ultrasound standard for fetal growth.

How often does the embryo implant at the location to which it was transferred?

OBJECTIVE

To determine how often the embryo implants exactly at the site of transfer and what additional factors may affect the eventual site of implantation in assisted reproductive technology (ART) cycles.

METHODS

This was a prospective observational study of women undergoing ART treatment in a tertiary university unit. Several factors inherent to the embryo transfer (ET), such as the location of the air bubbles and uterine contractility at 1 and at 60 min after ET were assessed with two-dimensional and three-dimensional (3D) ultrasound. In women in whom there was a resulting pregnancy, the position of the gestational sac (i.e. right, left, center or low) was subsequently assessed using 3D ultrasound, and predictors of its location were evaluated.

RESULTS

Of 239 recruited women with visualization of air bubbles at ET, 71 singleton gestational sacs were subsequently observed on 3D ultrasound. Overall, 40.8% (29/71) of embryos implanted at the location where the air bubbles were visualized at 1 min after ET, and 50.7% (36/71) implanted where the air bubbles were visualized at 60 min after ET (Cohen's kappa coefficients 0.21 and 0.37, respectively; comparison of agreement values: P = 0.28). Specifically, at 1 min the correspondence between the location of the air bubble and embryo implantation was 37.5% (6/16), 57.1% (8/14), 36.8% (7/19) and 36.4% (8/22) for right, left, central and lower uterus, respectively (4 × 4 contingency table, P < 0.01); at 60 min, the correspondence was 72.2% (13/18), 50.0% (9/18), 33.3% (8/24) and 85.7% (6/7), respectively (5 × 4 contingency table, P < 0.001). In addition, higher vs lower frequency of uterine contractions at 60 min was associated with different sites of implantation (5.6% (1/18), 11.1% (2/18), 27.8% (5/18) and 55.6% (10/18) vs 34.0% (18/53), 24.5% (13/53), 13.2% (7/53) and 28.3% (15/53) for right, left, central and lower uterus, respectively, P < 0.05). In particular, a high uterine contraction frequency following ET was associated with a twofold increased chance of the pregnancy implanting in the lower part of the uterine cavity (relative risk, 1.96 (95% CI, 1.08-3.56), P < 0.05).

CONCLUSIONS

The position of the air bubbles within the first 60 min of ET appears to predict the site of implantation in approximately half of cases, denoting an overall poor agreement. This implies significant embryo migration, and has important clinical implications, as it demonstrates that other factors such as uterine contractility may dictate where the embryo will eventually implant following transfer. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Comparison of Uterine Receptivity between Fertile and Unexplained Infertile Women by Assessment of Endometrial and Subendometrial Perfusion Using Contrast-Enhanced Ultrasound: Which Index is Better--Peak Intensity or Area under the Curve?

The goal of this study was to compare uterine receptivity between women with normal fertility and those with unexplained infertility during natural cycles by assessment of endometrial and subendometrial perfusion using contrast-enhanced ultrasound (CEUS). We wanted to determine the better index: peak intensity (PI) or area under the curve (AUC). Thirty women with unexplained infertility were recruited into the study group, and 30 women with normal fertility were recruited into the control group. All women underwent CEUS during the late proliferative phase, ovulation phase, and implantation window of a menstrual cycle. Endometrial PI, endometrial AUC, subendometrial PI and subendometrial AUC were analyzed. In the late proliferative phase, the control group had a significantly higher endometrial PI (p < 0.001) as well as subendometrial PI (p < 0.001) and AUC (p = 0.004) than the study group. In the ovulation phase, the control group had a significantly higher endometrial PI (p < 0.001) and AUC (p = 0.021), as well as subendometrial PI (p < 0.001) and AUC (p = 0.003). During the implantation window, there were no significant differences between the two groups. Only subendometrial PI underwent a significant periodic change during the menstrual cycle in both groups. This finding was further confirmed by evaluation of the microvessel density of endometria. In conclusion, CEUS can be used to assess endometrial and subendometrial perfusion to evaluate uterine receptivity. Subendometrial PI was the most sensitive index compared with endometrial PI, endometrial AUC and subendometrial AUC.

Reproducibility of first- and second-trimester uterine artery pulsatility index measured by transvaginal and transabdominal ultrasound

OBJECTIVES

To examine and compare the reproducibility of measurement of first- and second-trimester uterine artery pulsatility index (UtA-PI) using transabdominal (TAS) and transvaginal (TVS) ultrasound.

METHODS

This was an observational study including women ≥ 18 years of age, with a singleton pregnancy, in the first trimester (between 11 + 0 and 13 + 6 weeks' gestation) or second trimester (between 20 and 26 weeks' gestation). UtA-PI and angle of insonation were assessed by two observers (one with 15 and the other with 3 years of experience) using both TAS and TVS. The more experienced observer performed two scans alternated by the other observer. The acquisitions were completely independent and the observers were blinded to each other and to their own measurements. Reproducibility of the measurements by TVS and TAS was assessed using the concordance correlation coefficients (CCCs), intraclass correlation coefficients (ICCs) and limits of agreement (LoA).

RESULTS

We analyzed data from 97 women in the first trimester and 96 in the second trimester. The mean ± SD UtA-PI was significantly higher when measured using TVS, compared with TAS, in both the first (1.60 ± 0.49 vs 1.52 ± 0.63, respectively; P = 0.03) and second (1.07 ± 0.33 vs 0.96 ± 0.32, respectively; P < 0.001) trimesters. The median angle of insonation was significantly lower when using TVS, compared with TAS, in both the first (8.0° (interquartile range (IQR), 2.5-16.3°) vs 12.5° (IQR, 2.5-20.0°), respectively; P = 0.04) and second (10.0° (IQR, 4.5-16.5°) vs 17.5° (IQR, 5.0-27.9°), respectively; P < 0.001) trimesters. Both ultrasound techniques had similar reproducibility: the intraobserver CCC ranged from 0.93 to 0.95 and the interobserver CCC ranged from 0.81 to 0.86; and the ICCs of both techniques were highly comparable (the intraobserver LoA was approximately ± 20-30% and the interobserver LoA was approximately ± 30-40%).

CONCLUSIONS

When measuring UtA-PI, assessment by TVS provides higher values and better insonation angle compared with TAS. The reproducibility of the ultrasound methods in both first and second trimesters of pregnancy was comparable and should not be considered as good. Future studies examining technical improvements with the aim of increasing the reproducibility of this technique should be encouraged.

Fetal thymus: visualization rate and volume by integrating 2D- and 3D-ultrasound during 2nd trimester echocardiography

OBJECTIVE

To assess the visualization rate and transverse diameter of fetal thymus by two-dimensional ultrasound (2DUS) as well as the fetal thymus volume by three-dimensional ultrasound (3DUS) during the 2nd trimester echocardiography.

METHODS

A prospective cross-sectional study involving 100 normal fetuses between 18w0d and 23w6d was performed. The identification of fetal thymus and peri-thymic vessels was realized at level of three vessels and trachea (3VT). The transverse diameter was obtained placing a line cursor perpendicular to the line connecting the sternum and the spine. The fetal thymus volume was obtained by virtual organ computer-aided analysis (VOCAL) with 30° of rotation. We used the percentage of visualization rate of 2D structures and means and 95% confidence intervals (CI) for fetal thymus transverse diameter and volume.

RESULTS

The visualization rate of fetal thymus by 2DUS was of 100% in all gestational ages using the 3VT view. Addition of color Doppler ultrasound facilitates identification of the thy-box and enhanced the calculation of both fetal thymus transverse diameter and volume. The mean fetal thymus transverse diameter by 2DUS ranged from 11 mm at 18 weeks to 19 mm at 23 weeks of gestation. The mean fetal thymus volume by 3DUS ranged from 1.25 cm(3) at 18 weeks to 2.61 cm(3) at 23 weeks of gestation.

CONCLUSION

We demonstrated a high visualization rate of fetal thymus and peri-thymic vessels by 2DUS during the 2nd trimester echocardiography. The measurements of transverse diameter by 2DUS and the volume by 3DUS also showed a high success rate.