Intra- and interobserver agreement with regard to describing adnexal masses using International Ovarian Tumor Analysis terminology: reproducibility study involving seven observers

OBJECTIVES

To estimate intraobserver repeatability and interobserver agreement in assessing the presence of papillary projections in adnexal masses and in classifying adnexal masses using the International Ovarian Tumor Analysis terminology for ultrasound examiners with different levels of experience. We also aimed to identify ultrasound findings that cause confusion and might be interpreted differently by different observers, and to determine if repeatability and agreement change after consensus has been reached on how to interpret 'problematic' ultrasound images.

METHODS

Digital clips (two to eight clips per adnexal mass) with gray-scale and color/power Doppler information of 83 adnexal masses in 80 patients were evaluated independently four times, twice before and twice after a consensus meeting, by four experienced and three less experienced ultrasound observers. The variables analyzed were tumor type (unilocular, unilocular solid, multilocular, multilocular solid, solid) and presence of papillary projections. Intraobserver repeatability was evaluated for each observer (percentage agreement, Cohen's kappa). Interobserver agreement was estimated for all seven observers (percentage agreement, Fleiss kappa, Cohen's kappa).

RESULTS

There was uncertainty about how to define a solid component and a papillary projection, but consensus was reached at the consensus meeting. Interobserver agreement for tumor type was good both before and after the consensus meeting, with no clear improvement after the meeting, mean percentage agreement being 76.0% (Fleiss kappa, 0.695) before the meeting and 75.4% (Fleiss kappa, 0.682) after the meeting. Interobserver agreement with regard to papillary projections was moderate both before and after the consensus meeting, with no clear improvement after the meeting, mean percentage agreement being 86.6% (Fleiss kappa, 0.536) before the meeting and 82.7% (Fleiss kappa, 0.487) after it. There was substantial variability in pairwise agreement for papillary projections (Cohen's kappa, 0.148-0.787). Intraobserver repeatability with regard to tumor type was very good and similar before and after the consensus meeting (agreement 87-95%, kappa, 0.83-0.94). With regard to papillary projections intraobserver repeatability was good or very good both before and after the consensus meeting (agreement 88-100%, kappa, 0.64-1.0).

CONCLUSIONS

Despite uncertainty about how to define solid components, interobserver agreement was good for tumor type. The interobserver agreement for papillary projection was moderate but very variable between observer pairs. The term 'papillary projection' might need a more precise definition. The consensus meeting did not change inter- or intraobserver agreement.

Intra- and interobserver reproducibility of assessment of Doppler ultrasound findings in adnexal masses

OBJECTIVES

To estimate intra- and interobserver reproducibility and reliability of assessment of the color content in adnexal masses at color/power Doppler ultrasound examination for observers with different levels of experience, and to determine if they change after a consensus meeting.

METHODS

Digital clips with color/power Doppler information on 103 adnexal masses were evaluated independently four times, twice before and twice after a consensus meeting, by four experienced and three less experienced ultrasound examiners. The color content of the adnexal mass was estimated using the International Ovarian Tumor Analysis color score and a 100-mm visual analog scale (VAS score). Intraobserver repeatability was estimated for each observer. Interobserver agreement was estimated for the four most experienced observers (six pairs), for the three less experienced observers (three pairs), and for four other pairs of observers, each pair consisting of one of the experienced and one of the less-experienced observers.

RESULTS

Intra- and interobserver agreement for the color score was moderate to very good, percentage agreement ranging from 48 to 82.5% (kappa, 0.52-0.82) before and from 59 to 90% (kappa, 0.60-0.88) after the consensus meeting. For seven of 13 pairs of observers, interobserver agreement improved after the consensus meeting. Intraobserver intraclass correlation coefficient (ICC) values for the VAS score ranged from 0.80 to 0.92 before and from 0.75 to 0.94 after the consensus meeting, but limits of agreement were wide (± 20-35 mm). For six of the seven observers the ICC values were higher after the consensus meeting than before. Interobserver ICC values for the VAS score ranged from 0.77 to 0.88 before and from 0.77 to 0.91 after the consensus meeting, but limits of agreement were wide (± 30-40 mm). For 10 of 13 pairs of observers the ICC values improved after the consensus meeting.

CONCLUSIONS

Intra- and interobserver agreement for the color score was good, especially after the consensus meeting, but there is room for improvement. VAS score results varied substantially within and between observers both before and after the consensus meeting. General consensus needs to be reached about how to interpret color/power Doppler ultrasound findings in adnexal masses.

Intra- and interobserver agreement when describing adnexal masses using the International Ovarian Tumor Analysis terms and definitions: a study on three-dimensional ultrasound volumes

OBJECTIVES

To estimate intraobserver repeatability and interobserver agreement in: (1) describing adnexal masses using the International Ovarian Tumor Analysis (IOTA) terms and definitions; (2) the risk of malignancy calculated using IOTA logistic regression model 1 (LR1) and model 2 (LR2); and (3) the diagnosis made on the basis of subjective assessment of ultrasound images.

METHODS

One-hundred and three adnexal masses were examined by transvaginal gray-scale and power Doppler ultrasound. Three-dimensional ultrasound volumes of the mass were saved. After 12-18 months the volumes were analyzed twice, 1-6 months apart, by each of two independent experienced sonologists who used the IOTA terms and definitions to describe the masses. The risk of malignancy was calculated using LR1 and LR2. The sonologists also classified the masses as benign or malignant using subjective assessment.

RESULTS

Eighty-four masses were benign, eight were borderline and 11 were invasively malignant. There was substantial variability within and between observers in the results of measurements included in LR1 and LR2 and some variability also when assessing categorical variables included in the models (agreement = 51-100% and kappa = 0.42-1.00). This resulted in substantial variability in the calculated risk of malignancy, the limits of agreement indicating that the calculated risk of malignancy could vary by a factor of 5-20 within and between observers. The reliability of the calculated risk of malignancy was moderate (LR1) or poor (LR2) when the calculated risk of malignancy was > 10% (intraclass correlation coefficients varied from 0.21 to 0.73). Interobserver agreement when classifying tumors as benign or malignant using the predetermined risk of malignancy cut-off of 10% was fair to good (agreement = 85% and kappa = 0.61 for LR1; agreement = 81% and kappa = 0.52 for LR2). Intra- and interobserver agreements for subjective assessment were 96%, 96% and 96% with kappa values of 0.89, 0.87 and 0.88, respectively.

CONCLUSIONS

Intra- and interobserver agreement in classifying tumors as benign or malignant using the risk of malignancy cut-off of 10% for LR1 and LR2 was fair or good, whilst the reproducibility of subjective assessment was excellent. The reliability of calculated risks > 10% was poor, and calculated risk > 10% cannot be used to discriminate between individuals at different risk. These results cannot be extrapolated to real-time ultrasound examinations.

Prediction of endometrial malignancy in women with postmenopausal bleeding and sonographic endometrial thickness ≥ 4.5 mm

OBJECTIVE

To build mathematical models for evaluating the individual risk of endometrial malignancy in women with postmenopausal bleeding and sonographic endometrial thickness ≥ 4.5 mm using clinical data, sonographic endometrial thickness and power Doppler ultrasound findings.

METHODS

Of 729 consecutive patients with postmenopausal bleeding, 261 with sonographic endometrial thickness ≥ 4.5 mm and no fluid in the uterine cavity were included. They underwent transvaginal two-dimensional gray-scale and power Doppler ultrasound examination of the endometrium. The ultrasound image showing the most vascularized section through the endometrium as assessed by power Doppler was frozen, the endometrium was outlined and the percentage vascularized area (vascularity index) was calculated using computer software. The ultrasound examiner also estimated the color content of the endometrial scan on a visual analog scale (VAS) graded from 0 to 100 (VAS score). A structured history was taken to collect clinical information. Multivariate logistic regression analysis was used to create mathematical models to predict endometrial malignancy.

RESULTS

There were 63 (24%) malignant and 198 (76%) benign endometria. Women with a malignant endometrium were older (median age 74 vs. 65 years; P = 0.0005) and fewer used hormone replacement therapy and warfarin. Women with a malignant endometrium had a thicker endometrium (median thickness 20.8 vs. 10.2 mm; P = 0.0005) and higher values for vascularity index and VAS score. When using only clinical data to build a model for estimating the risk of endometrial malignancy, a model including the variables age, use of warfarin and use of hormone replacement therapy had the largest area under the receiver-operating characteristics curve (AUC), with a value of 0.74 (95% confidence interval (CI), 0.67-0.81). A model including age, use of warfarin and endometrial thickness had an AUC of 0.82 (95% CI, 0.76-0.87), and one including age, use of hormone replacement therapy, endometrial thickness and vascularity index had an AUC of 0.91 (95% CI, 0.87-0.95). Using a risk cut-off of 11%, the latter model had sensitivity 90%, specificity 71%, positive likelihood ratio 3.14 and negative likelihood ratio 0.13.

CONCLUSIONS

The diagnostic performance of models predicting endometrial cancer increases substantially when sonographic endometrial thickness and power Doppler information are added to clinical variables. The models are likely to be clinically useful but need to be prospectively validated.

Three-dimensional ultrasound imaging for discrimination between benign and malignant endometrium in women with postmenopausal bleeding and sonographic endometrial thickness of at least 4.5 mm

OBJECTIVES

To determine whether endometrial volume or power Doppler indices as measured by three-dimensional (3D) ultrasound imaging can discriminate between benign and malignant endometrium, to compare their diagnostic performance with that of endometrial thickness measurement using two-dimensional (2D) ultrasound examination, and to determine whether power Doppler indices add any diagnostic information to endometrial thickness or volume.

METHODS

Sixty-two patients with postmenopausal bleeding and endometrial thickness > or = 4.5 mm underwent transvaginal 2D gray-scale and 3D power Doppler ultrasound examination of the corpus uteri. The endometrial volume was calculated, along with the vascularization index (VI), flow index and vascularization flow index (VFI) in the endometrium and in a 2-mm 'shell' surrounding the endometrium. The 'gold standard' was the histological diagnosis of the endometrium obtained by hysteroscopic resection of focal lesions, dilatation and curettage or hysterectomy. Receiver-operating characteristics (ROC) curves were drawn for all measurements to evaluate their ability to distinguish between benign and malignant endometrium. Multivariate logistic regression analysis was used to create mathematical models to estimate the risk of endometrial malignancy.

RESULTS

There were 49 benign and 13 malignant endometria. Endometrial thickness and volume were significantly larger in malignant than in benign endometria, and flow indices in the endometrium and endometrial shell were significantly higher. The area under the ROC curve (AUC) of endometrial thickness was 0.82, that of endometrial volume 0.78, and that of the two best power Doppler variables (VI and VFI in the endometrium) 0.82 and 0.82. The best logistic regression model for predicting malignancy contained the variables endometrial thickness (odds ratio 1.2; 95% CI, 1.04-1.30; P = 0.004) and VI in the endometrial 'shell' (odds ratio 1.1; 95% CI, 1.02-1.23; P = 0.01). Its AUC was 0.86. Using its mathematically optimal risk cut-off value (0.22), the model correctly classified seven more benign cases but two fewer malignant cases than the best endometrial thickness cut-off (11.8 mm). Models containing endometrial volume and flow indices performed less well than did endometrial thickness alone (AUC, 0.79 vs. 0.82).

CONCLUSIONS

The diagnostic performance for discrimination between benign and malignant endometrium of 3D ultrasound imaging was not superior to that of endometrial thickness as measured by 2D ultrasound examination, and 3D power Doppler imaging added little to endometrial thickness or volume.

Two- and three-dimensional saline contrast sonohysterography: interobserver agreement, agreement with hysteroscopy and diagnosis of endometrial malignancy

OBJECTIVES

The aims of our study were to compare the interobserver reproducibility of two-dimensional (2D) and three-dimensional (3D) saline contrast sonohysterography (SCSH) and agreement of these techniques with hysteroscopy, and to determine which SCSH findings best discriminate between benign and malignant endometrium.

METHODS

Consecutive women with postmenopausal bleeding and endometrial thickness > or = 4.5 mm underwent 2D and 3D SCSH; the results were videotaped and stored electronically, respectively, for analysis by two independent experienced examiners who were blinded to each other's results. A histological diagnosis was obtained by dilatation and curettage, hysteroscopic resection or hysterectomy. The hysteroscopist was blinded to the ultrasound results and used the same standardized research protocol to describe the uterine cavity as the ultrasound examiners.

RESULTS

Of 170 consecutive women with postmenopausal bleeding and endometrial thickness > or = 4.5 mm, 84 (14 with endometrial malignancy) fulfilled our inclusion criteria. Hysteroscopy findings in 54 women (one with endometrial malignancy) were used to determine agreement with SCSH. Interobserver agreement of 2D and 3D SCSH was 95% (80/84) vs. 89% (75/84) with regard to presence of focal lesions, 89% (75/84) vs. 88% (74/84) for presence of focal lesions with irregular surface, 67% (54/81) vs. 63% (51/81) for number of focal lesions, and 77% (46/60) vs. 70% (42/60) for location of focal lesions. The agreement between 2D and 3D SCSH and hysteroscopy was 94% (51/54) vs. 93% (50/54) with regard to presence of focal lesions, 74% (40/54) vs. 76% (41/54) for presence of focal lesions with irregular surface, 63% (34/54) vs. 54% (29/54) for number of focal lesions, and 66% (29/44) vs. 64% (28/44) for location of focal lesions. The SCSH finding that best discriminated between benign and malignant endometrium was the presence of focal lesion(s) with irregular surface (for 2D SCSH: sensitivity 71%, specificity 97%, positive likelihood ratio 25, negative likelihood ratio 0.3; for 3D SCSH: sensitivity 43%, specificity 97%, positive likelihood ratio 15, negative likelihood ratio 0.6).

CONCLUSIONS

3D SCSH does not seem to be superior to 2D SCSH when performed by experienced ultrasound examiners either with regard to reproducibility, agreement with hysteroscopy findings or diagnosis of endometrial malignancy. The presence of focal lesion(s) with irregular surface is the best SCSH variable for discrimination between benign and malignant endometrium.

Contribution of morphological assessment of the vessel tree by three-dimensional ultrasound to a correct diagnosis of malignancy in ovarian masses

OBJECTIVE

To determine whether subjective evaluation of the morphology of the vessel tree of ovarian tumors, as depicted by three-dimensional (3D) power Doppler ultrasound, can discriminate between benign and malignant ovarian tumors, and whether it improves characterization compared with using gray-scale ultrasound imaging alone.

METHODS

A consecutive series of 104 women scheduled for surgical removal of an ovarian mass were examined with transvaginal two-dimensional (2D) gray-scale and 3D power Doppler ultrasound. Predetermined vessel characteristics, e.g. density of vessels, branching, caliber changes and tortuosity, were evaluated in 360 degrees rotating 3D images of the vessel tree of the tumor. Ultrasound results were compared with those of the histology of the surgical specimens. Univariate and multivariate logistic regression were used.

RESULTS

There were 77 benign tumors, six borderline tumors and 21 invasive malignancies. All vascular features differed significantly between benign and malignant tumors. The areas under their receiver-operating characteristics (ROC) curves (AUCs) were in the range 0.61-0.83. The AUC of a logistic regression model containing three gray-scale ultrasound variables was 0.98. This model correctly classified all malignancies, with a false-positive rate of 10% (8/77). Adding branching of vessels in the whole tumor to the gray-scale model yielded an AUC of 0.99 and resulted in all malignancies and an additional four benign tumors being correctly classified.

CONCLUSIONS

Subjective evaluation of the morphology of the vessel tree, as depicted by 3D power Doppler ultrasound, can be used to discriminate between benign and malignant ovarian tumors, but adds little to gray-scale ultrasound imaging in an ordinary population of tumors.

Ultrasound assessment of endometrial morphology and vascularity to predict endometrial malignancy in women with postmenopausal bleeding and sonographic endometrial thickness >or= 4.5 mm

OBJECTIVES

To determine which endometrial morphology characteristics as assessed by gray-scale ultrasound and which endometrial vessel characteristics as assessed by power Doppler ultrasound are useful for discriminating between benign and malignant endometrium in women with postmenopausal bleeding (PMB) and sonographic endometrial thickness >or= 4.5 mm and to develop logistic regression models to calculate the individual risk of endometrial malignancy in women with PMB, endometrial thickness >or= 4.5 mm, good visibility of the endometrium and detectable Doppler signals in the endometrium.

METHODS

Of 223 consecutive patients with PMB and sonographic endometrial thickness >or= 4.5 mm, 120 fulfilled our inclusion criteria. They underwent transvaginal gray-scale and power Doppler ultrasound examination, which was videotaped for later analysis by two examiners with more than 15 years' experience in gynecological ultrasonography. They independently assessed endometrial morphology and vascularity using predetermined criteria. Their agreed-upon description was compared with the histological diagnosis. Univariate and multivariate logistic regression analyses were used. The best diagnostic test was defined as the one with the largest area under the receiver-operating characteristics curve (AUC).

RESULTS

Thirty (25%) endometria were malignant. Inter-observer agreement for the description of endometrial morphology and vascularity was moderate to good (Kappa 0.49-0.78). The best ultrasound variables to predict malignancy were heterogeneous endometrial echogenicity (AUC 0.83), endometrial thickness (AUC 0.80), and irregular branching of endometrial blood vessels (AUC 0.77). A logistic regression model including endometrial thickness and heterogeneous endometrial echogenicity had an AUC of 0.91. Its mathematically best risk cut-off yielded a positive likelihood ratio of 4.4, and a negative likelihood ratio of 0.1. Adding Doppler information to the model improved diagnostic performance marginally (AUC 0.92).

CONCLUSIONS

In selected high-risk women with PMB and an endometrial thickness of >or= 4.5 mm, calculation of the individual risk of endometrial malignancy using regression models including gray-scale and Doppler characteristics can be used to tailor management. These models would need to be tested prospectively before introduction into clinical practice.

Does three-dimensional power Doppler ultrasound help in discrimination between benign and malignant ovarian masses?

OBJECTIVES

To determine if tumor vascularity as assessed by three-dimensional (3D) power Doppler ultrasound can be used to discriminate between benign and malignant ovarian tumors, if adding 3D power Doppler ultrasound to gray-scale imaging improves differentiation between benignity and malignancy, and if 3D power Doppler ultrasound adds more to gray-scale ultrasound than does two-dimensional (2D) power Doppler ultrasound.

METHODS

One hundred and six women scheduled for surgery because of an ovarian mass were examined with transvaginal gray-scale ultrasound and 2D and 3D power Doppler ultrasound. The color content of the tumor scan was rated subjectively by the ultrasound examiner on a visual analog scale. Vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were calculated in the whole tumor and in a 5-cm(3) sample taken from the most vascularized area of the tumor. Logistic regression analysis was used to build models to predict malignancy.

RESULTS

There were 79 benign tumors, six borderline tumors and 21 invasive malignancies. A logistic regression model including only gray-scale ultrasound variables (the size of the largest solid component, wall irregularity, and lesion size) was built to predict malignancy. It had an area under the receiver-operating characteristics (ROC) curve of 0.98, sensitivity of 100%, false positive rate of 10%, and positive likelihood ratio (LR) of 10 when using the mathematically best cut-off value for risk of malignancy (0.12). The diagnostic performance of the 3D flow index with the best diagnostic performance, i.e. VI in a 5-cm(3) sample, was superior to that of the color content of the tumor scan (area under ROC curve 0.92 vs. 0.80, sensitivity 93% vs. 78%, false positive rate 16% vs. 27% using the mathematically best cut-off value). Adding the color content of the tumor scan or FI in a 5-cm(3) sample to the logistic regression model including the three gray-scale variables described above improved diagnostic performance only marginally, an additional two tumors being correctly classified.

CONCLUSIONS

Even though 2D and 3D power Doppler ultrasound can be used to discriminate between benign and malignant ovarian tumors, their use adds little to a correct diagnosis of malignancy in an ordinary population of ovarian tumors. Objective quantitation of the color content of the tumor scan using 3D power Doppler ultrasound does not seem to add more to gray-scale imaging than does subjective quantitation by the ultrasound examiner using 2D power Doppler ultrasound.

Reference data representative of normal findings at three-dimensional power Doppler ultrasound examination of the cervix from 17 to 41 gestational weeks

OBJECTIVES

To develop normal reference ranges for cervical volume and vascular indices using three-dimensional (3D) power Doppler ultrasonography from 17 to 41 gestational weeks.

METHODS

This was a cross-sectional study of 352 nulliparous and 291 parous women who delivered at term and underwent transvaginal 3D power Doppler ultrasound examination of the cervix once at 17 to 41 weeks' gestation. We examined approximately 25 women in each gestational week. Cervical volume, vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were calculated.

RESULTS

There was no change in cervical volume between 17 and 40 weeks' gestation. At 41 weeks cervical volume was slightly smaller than it was at 17-40 weeks (P=0.03 for nulliparous women and P=0.08 for parous women). The cervical volume was larger in parous than it was in nulliparous women (median 38 cm3 vs. 32 cm3 at 17-40 weeks, P<0.0001; median 31 cm3 vs. 22 cm3 at 41 gestational weeks, P=0.288). FI did not differ between nulliparous and parous women and remained unchanged between 17 and 41 weeks' gestation (median 30.6, range 21.2-55.2). VI and VFI did not change consistently from 17 to 41 weeks, but the values were higher in parous than they were in nulliparous women at 17-30 weeks (median VI 5.3% vs. 3.1%, P<0.0001; median VFI 1.6 vs. 0.9, P<0.0001). At 31-41 gestational weeks the median VI for all women irrespective of parity was 4.9% and the median VFI was 1.4.

CONCLUSION

Reference values for cervical volume and blood flow indices as assessed by 3D power Doppler ultrasonography have been established for the second half of pregnancy. These lay the basis for studies of pathological conditions.

Bishop score and ultrasound assessment of the cervix for prediction of time to onset of labor and time to delivery in prolonged pregnancy

OBJECTIVES

To determine the ability of Bishop score and sonographic cervical length to predict time to spontaneous onset of labor and time to delivery in prolonged pregnancy.

METHODS

Ninety-seven women underwent transvaginal ultrasound examination and palpation of the cervix at 291-296 days' gestation according to ultrasound fetometry at 12-20 weeks' gestation. Sonographic cervical length and Bishop score were recorded. Multivariate logistic regression analysis was used to determine which variables were independent predictors of the onset of labor/delivery < or = 24 h, < or = 48 h, and < or = 96 h. Receiver-operating characteristics (ROC) curves were drawn to assess diagnostic performance.

RESULTS

In nulliparous women (n = 45), both Bishop score and sonographic cervical length predicted the onset of labor/delivery < or = 24 h and < or = 48 h (area under ROC curve for the onset of labor < or = 24 h 0.79 vs. 0.80, P = 0.94; for delivery < or = 24 h 0.81 vs. 0.85, P = 0.64; for the onset of labor < or = 48 h 0.73 vs. 0.74, P = 0.90; for delivery < or = 48 h 0.77 vs. 0.71, P = 0.50). Only Bishop score discriminated between nulliparous women who went into labor/delivered < or = 96 h or > 96 h. A logistic regression model including Bishop score and cervical length was superior to Bishop score alone in predicting delivery < or = 24 h (area under ROC curve 0.93 vs. 0.81, P = 0.03) and superior to Bishop score alone and cervical length alone in predicting the onset of labor < or = 24 h (area under ROC curve 0.90 vs. 0.79, P = 0.06; and 0.90 vs. 0.80, P = 0.06). In parous women (n = 52), Bishop score and sonographic cervical length predicted the onset of labor/delivery < or = 24 h (area under ROC curve for the onset of labor 0.75 vs. 0.69, P = 0.49; for delivery 0.74 vs. 0.70, P = 0.62), but only Bishop score discriminated between women who went into labor/delivered < or = 48 h and > 48 h. Three parous women had not gone into labor and six had not given birth at 96 h. In parous women logistic regression models including both Bishop score and cervical length did not substantially improve prediction of the time to onset of labor/delivery.

CONCLUSIONS

In prolonged pregnancy Bishop score and sonographic cervical length have a similar ability to predict the time to the onset of labor and delivery. In nulliparous women the use of logistic regression models including Bishop score and cervical length is likely to offer better prediction of the onset of labor/delivery < or = 24 h than the use of the Bishop score alone.

Three-dimensional ultrasound assessment of the cervix for predicting time to spontaneous onset of labor and time to delivery in prolonged pregnancy

OBJECTIVES

To determine whether three-dimensional (3D) ultrasound including power Doppler examination of the cervix is useful for predicting time to spontaneous onset of labor or time to delivery in prolonged pregnancy.

METHODS

A prospective study was conducted in 60 women who went into spontaneous labor. All underwent transvaginal 3D power Doppler ultrasound examination of the cervix immediately before a prolonged-pregnancy check-up at > or = 41 + 5 gestational weeks. Univariate and multivariate logistic regression analysis was used to determine which of the following variables predicted spontaneous onset of labor > 24 h and > 48 h and vaginal delivery > 48 h and > 60 h: length, anteroposterior (AP) diameter and width of the cervix and of any cervical funneling; cervical volume (cm3); vascularization index (VI); flow index (FI); vascularization flow index (VFI); parity; and Bishop score. Multivariate logistic regression analysis was carried out both with and without Bishop score as a predictive variable. Receiver-operating characteristics (ROC) curves were used to describe the diagnostic performance of the tests.

RESULTS

The areas under the ROC curves for Bishop score, cervical length, and logistic regression models did not differ significantly (areas ranging from 0.72 to 0.82). If Bishop score was not included in the logistic regression model, cervical length, VI and FI independently predicted delivery > 48 h, the likelihood increasing with increasing cervical length, decreasing VI and increasing FI.

CONCLUSIONS

In prolonged pregnancy cervical vascularization as estimated by 3D power Doppler ultrasound is related to time to delivery > 48 h, but the likelihood of delivery > 48 h can be predicted equally well using Bishop score alone or sonographic cervical length alone.

Assessment of changes in endometrial and subendometrial volume and vascularity during the normal menstrual cycle using three-dimensional power Doppler ultrasound

OBJECTIVES

To describe changes in endometrial and subendometrial volume and vascularity during the normal menstrual cycle using three-dimensional (3D) power Doppler ultrasonography.

METHODS

Fourteen healthy volunteers, 24-44 years old with regular menstrual cycles, underwent serial transvaginal 3D power Doppler ultrasound examinations of the uterus on cycle day 2, 3 or 4, then daily from cycle day 9 until follicular rupture and 1, 2, 5, 7 and 12 days after follicular rupture. Endometrial and subendometrial volume (cm3), vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were calculated using the VOCAL (Virtual Organ Computer-aided AnaLysis) software.

RESULTS

Endometrial and subendometrial vascularity indices increased throughout the follicular phase, decreased to a nadir 2 days after follicular rupture and then increased again during the luteal phase. Endometrial and subendometrial volume increased rapidly during the follicular phase and then remained almost unchanged during the luteal phase.

CONCLUSIONS

Substantial changes occur in endometrial volume and vascularization during the normal menstrual cycle. There is the potential for 3D power Doppler ultrasonography to become a useful tool for assessing pathological changes associated with female subfertility and abnormal uterine bleeding.

Reference data representative of normal findings at two-dimensional and three-dimensional gray-scale ultrasound examination of the cervix from 17 to 41 weeks' gestation

OBJECTIVES

To create reference values representative of normal findings on two-dimensional (2D) and three-dimensional (3D) transvaginal ultrasound (TVS) examination of the cervix from 17 to 41 weeks' gestation and to determine the agreement between cervical measurements taken by 2D and 3D TVS.

METHODS

Cross-sectional study covering 17 to 41 weeks in 419 nulliparous and 360 parous women who delivered at term and who underwent 2D and 3D TVS examination of the uterine cervix. We examined approximately 25 women in each gestational week. The length, anteroposterior (AP) diameter and width of the cervix (and of any cervical funnel) and AP diameter of the cervical canal were measured. Results were plotted against gestational age. The agreement between 2D and 3D ultrasound results was expressed as the mean (+/- 2 SDs) difference between the results of the two methods and as the interclass correlation coefficient (inter-CC).

RESULTS

There was excellent agreement between measurements taken by 2D and 3D ultrasound (inter-CC values, 0.80-0.98) but measurements of cervical length taken using 3D ultrasound were greater than measurements taken by 2D ultrasound (mean difference, -0.04 +/- 0.36 cm). Cervical length did not change substantially between 17 and 32 gestational weeks but decreased progressively thereafter. Cervical length was similar in nulliparous and parous women at 17-32 weeks, but from 33 weeks the cervix tended to be longer in parous women. In nulliparae, cervical length decreased from a median of 3.8 (range, 0.7-6.1) cm at 17-32 weeks to 2.3 (range, 0.4-6.0) cm at 33-40 weeks and to 0.7 (range, 0.2-1.5) cm at 41 weeks. In parous women, the corresponding figures were 3.9 (range, 1.0-6.1) cm, 3.0 (range, 0.4-5.7) cm and 0.8 (range, 0.4-3.4) cm (results obtained by 3D ultrasound). Cervical AP diameter and width did not differ between nulliparous and parous women. Median AP diameter increased from 3.0 (range, 2.0-4.6) cm at 17-30 weeks to 3.5 (range, 1.8-5.5) cm at 31-40 weeks and to 4.0 (range, 2.8-5.9) cm at 41 weeks. Cervical width was 3.7 (range, 2.3-6.0) cm at 17-30 weeks and 4.5 (range, 2.3-6.1) cm at 31-41 weeks. The percentage of women with funneling increased from 4% (3/84) at 17-18 weeks to 63% (12/19) at 41 weeks and the percentage of women with an open cervical canal increased from 19% (15/84) to 72% (13/19). Funneling and opening of the cervical canal were equally common in nulliparous and parous women.

CONCLUSIONS

Reference data provide the basis for studies of pathological conditions. Common reference values for nulliparous and parous women can be used for cervical AP diameter and width from 17 to 41 weeks and for cervical length from 17 to 32 weeks. Separate reference values for cervical length for nulliparous and parous women should be used from 33 to 41 weeks.

Evaluation of endometrial receptivity during in-vitro fertilization using three-dimensional power Doppler ultrasound

OBJECTIVE

To compare sonographic endometrial characteristics in in-vitro fertilization (IVF) cycles between women who conceive and those who do not.

METHODS

Thirty-five women undergoing IVF treatment participated in the study. Using three-dimensional (3D) power Doppler ultrasound, we assessed endometrial patterns, volume and vascularization, after follicle stimulating hormone (FSH) stimulation but before human chorionic gonadotropin (hCG) administration (referred to hereafter as 'after FSH stimulation') and again on the day of oocyte retrieval.

RESULTS

The pregnancy rate was 37% (13/35). After FSH stimulation, 29 of the 35 women had a triple-line endometrial pattern, compared with five out of 35 on the day of oocyte retrieval. In those who had a triple-line pattern after FSH stimulation the pregnancy rate was 44.8% (13/29) and it was 0% (0/6) in those with a homogeneous pattern (chi-square test, P = 0.039). If a triple-line pattern was present on the day of oocyte retrieval the pregnancy rate was 80.0% (4/5), whereas if the pattern was homogeneous the pregnancy rate was 30.0% (9/30) (P = 0.032). There were no differences between those who conceived and those who did not in endometrial thickness, volume or vascularization on either day examined. Endometrial volume decreased significantly after hCG injection in women who conceived, but not in those who did not conceive. In both groups endometrial and subendometrial vascularization decreased after hCG injection, while the endometrial thickness remained unchanged.

CONCLUSIONS

The existence of a homogeneous endometrial pattern after FSH stimulation seems to be a prognostic sign of an adverse outcome in IVF, while a triple-line pattern after FSH stimulation and a decrease in endometrial volume appear to be associated with conception.

Ultrasound dating at 12-14 weeks of gestation. A prospective cross-validation of established dating formulae in in-vitro fertilized pregnancies

OBJECTIVES

To determine the accuracy of established ultrasound dating formulae when used at 12-14 weeks of gestation.

METHODS

One-hundred and sixty-seven singleton pregnancies conceived after in-vitro fertilization (IVF) underwent a dating scan at 12-14 weeks of gestation. Gestational age at the dating scan was calculated by adding 14 days to the number of days between the date of oocyte retrieval and the date of the ultrasound scan. Gestational age according to oocyte retrieval was regarded as the true gestational age. True gestational age was compared to gestational age calculated on the basis of 21 dating formulae based on fetal crown-rump length (CRL) measurements and to three dating formulae based on fetal biparietal diameter (BPD) measurements. In a previous study the three BPD formulae tested here had been shown to be superior to four other BPD formulae when used at 12-14 weeks of gestation. The mean of the differences between estimated and true gestational age and their standard deviation (SD) were calculated for each formula. The SD of the differences was assumed to reflect random measurement error. Systematic measurement error was assumed to exist if zero lay outside the mean difference+/-2SE (SE: standard error of the mean).

RESULTS

The three best CRL formulae were associated with mean (non-systematic) measurement errors of -0.0, -0.1 and -0.3 days, and the SD of the measurement errors of these formulae varied from 2.37 to 2.45. All but two of the remaining CRL formulae were associated with systematic over- or under-estimation of gestational age, and the SDs of their measurement error varied between 2.25 and 4.86 days. Dating formulae using BPD systematically underestimated gestational age by -0.4 to -0.7 days, and the SDs of their measurement errors varied from 1.86 to 2.09.

CONCLUSIONS

We have identified three BPD formulae that are suitable for dating at 12-14 weeks of gestation. They are superior to all 21 CRL formulae tested here, because their random measurement errors were much smaller than those of the three best CRL formulae. The small systematic negative measurement errors associated with the BPD formulae are likely to be clinically unimportant.

Intraobserver and interobserver reproducibility of three-dimensional gray-scale and power Doppler ultrasound examinations of the cervix in pregnant women

OBJECTIVES

To determine intraobserver and interobserver reproducibility of three-dimensional (3D) gray-scale and power Doppler ultrasound examinations of the cervix in pregnant women.

METHODS

Thirty-two pregnant women underwent transvaginal 3D gray-scale and power Doppler ultrasound examination of the cervix by two examiners. Each observer acquired two volumes, and they each analyzed their volumes twice using the commercially available software Virtual Organ Computer-aided AnaLysis (VOCAL). The variables analyzed were cervical volume (cm3), vascularization index (VI), flow index (FI) and vascularization flow index (VFI). Intraobserver repeatability was expressed as the difference between two measurement results (mean difference +/- 2 SD, i.e. limits of agreement) and as intraclass correlation coefficient (intra-CC). Interobserver agreement was expressed as the difference between the results of the two observers (limits of agreement) and as interclass correlation coefficient (inter-CC). The contribution of various factors (examiner, acquisition, analysis of acquired volume) to intrasubject variance was estimated using different analysis of variance models. All statistical analyses were performed using log-transformed data. The results presented are those obtained after antilogarithmic transformation, i.e. the results are presented as ratios between two results of the same observer, or as ratios between the results of Observer 1 and Observer 2.

RESULTS

All intraobserver and interobserver log-transformed differences were normally distributed. There was no systematic bias between the two observers. Both intra- and inter-CC values were high (0.93-0.98) for all variables except FI (0.63-0.88), despite the limits of agreement being wide, especially for VI (widest range 0.4-2.4) and VFI (widest range 0.3-2.6). Acquisition explained most of the intrasubject variance of the flow indices, the contribution of examiner and analysis being unimportant.

CONCLUSIONS

Given the wide range between the lower and upper limits of agreement, it would probably not be possible to detect anything but large differences or changes in cervical volume or cervical flow indices using current 3D ultrasound techniques. Because acquisition explained most of the intrasubject variance, the average of several repeated acquisitions should be used to enhance reproducibility. However, it is not worth doing more than one analysis of an acquired volume, because the effect of analysis on measurement results is small.

Intraobserver and interobserver variability of ovarian volume, gray-scale and color flow indices obtained using transvaginal three-dimensional power Doppler ultrasonography

OBJECTIVE

To assess intraobserver and interobserver variability in ovarian volume and gray-scale and color flow index measurements using transvaginal, three-dimensional, power Doppler ultrasonography.

METHODS

Eleven women (22 ovaries) were examined on day 8 of controlled ovarian hyperstimulation therapy, which was part of their in vitro fertilization treatment protocol. The patients were examined twice by the first observer and once by the second observer. The acquired volume datasets were analyzed using the VOCAL imaging program, enabling the assessment of ovarian volume, vascularization index (VI), flow index (FI), vascularization flow index (VFI) and mean grayness (MG). For these parameters the intraclass (intra-CC) and interclass (inter-CC) correlation coefficients, within-observer and between-observers repeatability coefficient (r) and limits of agreement were calculated.

RESULTS

Both intraobserver and interobserver repeatability of ovarian volume measurements were considered very good with an intra-CC value of 1.00 and inter-CC value of 0.99, respectively. Also VI, FI, VFI and MG measurements were repeatable by a single observer, the intra-CC ranging from 0.82 to 0.91. The interobserver reproducibility was also good for VI, VFI and MG measurements (inter-CC values 0.73, 0.70 and 0.81, respectively), but for FI measurements the reproducibility was poor (inter-CC = 0.29, r = 7.87).

CONCLUSIONS

In general, the intraobserver reproducibility was better than interobserver reproducibility for all parameters. The volume assessments were reproducible both by one observer and by two separate observers. The intraobserver and interobserver variabilities were acceptable for VI, VFI and MG, whereas for FI the interobserver reproducibility was poor. Our results suggest that measurement of gray-scale and color Doppler flow indices is reproducible thus allowing them to be used in clinical practice and research.

Characterization of normal and polycystic ovaries using three-dimensional power Doppler ultrasonography

PURPOSE

To evaluate the characteristics of polycystic compared to normal ovaries using three-dimensional (3-D) power Doppler ultrasonography.

METHODS

We recruited 42 volunteers, all of whom were commencing IVF treatment. Each patient was examined in the cycle preceeding the start of drug therapy during the late follicular phase. If eight or more subcapsular follicles of 2-8 mm in diameter in one two-dimensional (2-D) plane were detected in either of the ovaries, the patient was categorized as having polycystic ovaries (PCO); otherwise the ovaries were considered normal. The parameters examined were volume of the ovary, vascularization index (VI), flow index (FI), vascularization flow index (VFI), and mean greyness (MG). In addition, the ovary was arbitrarily divided into cortex and stroma, and thereafter volume, VI, FI, VFI, and MG were calculated for these two regions.

RESULTS

Twenty-eight women had normal ovaries and 14 had PCO. The comparison between normal and PCO showed that as a group the PCO were larger, without any differences in VI, Fl, VFI, or MG. In patients with PCO, the right ovary was larger than the left one. In patients with normal ovaries, Fl was higher on the left side. Division into cortex and stroma revealed that there were no differences in cortical or stromal VI, FI, VFI, or MG between normal and PCO on either side.

CONCLUSIONS

The ovaries defined as polycystic were larger than normal ovaries, but there was no difference in the echogenicity of the stroma between polycystic and normal ovaries. We were also unable to demonstrate that the polycystic ovarian stroma was more vascularized than the stroma in the normal ovaries.

Three-dimensional sonographic and power Doppler characterization of ovaries in late follicular phase

OBJECTIVE

To determine ovarian blood flow characteristics using three-dimensional power Doppler ultrasound.

METHODS

We examined 30 patients (30 cycles) prior to the start of their in vitro fertilization treatment in the late follicular phase using three-dimensional power Doppler ultrasound. The volume, vascularization index, flow index, vascularization flow index, mean grayness and the presence of the dominant follicle were determined for each ovary separately.

RESULTS

The dominant follicle could be detected in 24 out of 30 cycles (80.0%). The volume of the dominant ovary was 9.9 (standard deviation, 4.0) cm3 and the volume of the non-dominant ovary 6.8 (standard deviation, 2.8) cm3 (P < 0.001). Mean grayness in the dominant ovary was 43.3 (standard deviation, 5.0) and in the non-dominant 47.2 (standard deviation, 4.0) (P < 0.001), but no other differences could be observed between dominant and non-dominant ovaries. The shell with a diameter of 2 mm surrounding the dominant follicle had a higher vascularization index (mean, 9.0; standard deviation, 5.9) and vascularization flow index (mean, 4.2; standard deviation, 2.8) than the whole dominant ovary (mean, 5.5; standard deviation, 2.5 and mean, 2.5; standard deviation, 1.3, respectively) (P = 0.003 and 0.002, respectively). In the cycles without a dominant follicle (n = 6), flow index (mean, 50.0; standard deviation, 5.9) and vascularization flow index (mean, 7.3; standard deviation, 6.2) on the left side were higher than on the right side (mean, 40.2; standard deviation, 3.1; mean, 1.5; standard deviation, 1.4; P-values 0.013 and 0.046, respectively).

CONCLUSION

In the dominant ovary, the volume was higher and mean grayness lower than in the non-dominant ovary. The vascularization index in the shell surrounding the dominant follicle was higher than the average vascularization index in the whole dominant ovary. In addition, there were differences in the vascularization and flow indices between right and left ovaries, which may be related to the anatomical difference in the venous drainage between right and left ovaries.

Investigation of the infertile couple: a one-stop ultrasound-based approach

The appropriateness of many investigations for subfertility will continue to be of debate for some time yet. Of most benefit to the concerned couple would be a process that is diagnostically accurate, expeditious and reliable. It should be performed with a minimum of invasion and provide both patient and clinician with useful prognostic information regarding possible future treatment. This article is intended to illustrate the advantages of an ultrasound-based process of subfertility investigation. Discussed is the role of ultrasound compared with more invasive investigative methods such as laparoscopy and hysteroscopy. In addition, the potential capacity of newer advanced ultrasound technologies is reviewed.

Intraobserver reproducibility of Doppler measurements of uterine artery blood flow velocity in premenopausal women

OBJECTIVE

To determine the intraobserver repeatability of Doppler measurements of uterine artery blood flow velocity and the contribution of various factors to within-subject variance.

DESIGN

Seventeen healthy premenopausal women underwent vaginal Doppler ultrasound examination of the uterine artery by the same observer. Three measurements were taken at each of three sites: 1) the currently recommended sampling site; 2) the ascending branch of the uterine artery at a level between the lower and middle third of the corpus uteri; 3) 1.5 cm lateral to the recommended sampling site. Three measurements were taken at each site. For each measurement, three uniform consecutive cardiac cycles were analyzed. Peak systolic velocity, time-averaged maximum velocity, and pulsatility index were calculated. Each Doppler shift spectrum was analyzed twice. Thus, for each women, 18 measurement results per sampling site were obtained. Analysis of variance was used.

RESULTS

The effect of sampling site on measurements of peak systolic velocity and time-averaged maximum velocity was non-significant, but pulsatility index values obtained at the distal sampling site were slightly higher than those obtained at the other sites (P = 0.01). Repetition accounted for most of the within-subject variance. Averaging the results of the three repeat measurements yielded increased intraclass correlation coefficients: 0.79-0.89 for peak systolic velocity, 0.80-0.92 for time-averaged maximum velocity and 0.86-0.93 for pulsatility index.

CONCLUSION

As the effect of repetition on the results of Doppler measurements of uterine artery blood flow velocity is large, the average of several repeat measurements should be used to enhance measurement reproducibility. However, it is not worth doing more than one analysis of a Doppler shift spectrum, and it is not worth analyzing more than one cardiac cycle per spectrum.