Spherical tissue sampling in 3-dimensional power Doppler angiography: a new approach for evaluation of ovarian tumors

4D Doppler Ultrasound in High Grade Serous Ovarian Cancer Vascularity Evaluation-Preliminary Study

The aim of the study was to evaluate the usefulness of 4D Power Doppler tissue evaluation to discriminate between normal ovaries and ovarian cancer tumors. This was a prospective observational study. Twenty-three cases of surgically confirmed ovarian High Grade Serous Carcinoma (HGSC) were analyzed. The control group consisted of 23 healthy patients, each matching their study-group counterpart age wise (±3 years) and according to their menopausal status. Transvaginal Doppler 4D ultrasound scans were done on every patient and analyzed with 3D/4D software. Two 4D indices-volumetric Systolic/Diastolic Index (vS/D) and volumetric Pulsatility Index (vPI)-were calculated. To keep results standardized and due to technical limitations, virtual 1cc spherical tissue samples taken from the part with highest vascularization as detected by bi-directional Power Doppler were analyzed for both groups of ovaries. Values of volumetric S/D indices and volumetric PI indices were statistically lower in ovarian malignant tumors compared to normal ovaries: 1.096 vs. 1.794 and 0.092 vs. 0.558, respectively (p < 0.001). The 4D bi-directional Power Doppler vascular indices were statistically different between malignant tumors and normal ovaries. These findings could support the rationale for future studies for assessing this technology to discriminate between malignant and benign tumors.

Past, present and future ultrasonographic techniques for analyzing ovarian masses

Ultrasonography is today the method of choice for distinguishing between benign and malignant adnexal pathologies. Using pattern recognition several types of tumors can be recognized according to their characteristic appearance on gray-scale imaging. Color Doppler imaging should be used only to perform a semiquantitative color score or evaluate the flow location. International Ovarian Tumor Analysis group had standardized definitions characterizing adnexal masses and suggested the use of 'simple rules' in premenopausal women. Recently, the use of 3D vascular indices has been proposed but its potential use in clinical practice is debated. Also computerized aided diagnosis algorithms showed encouraging results to be confirmed in the future.

Limitations of three-dimensional power Doppler angiography in preoperative evaluation of ovarian tumors

Background

This study describes the accuracy of three-dimensional power Doppler (3D-PD) angiography as secondary method for differential diagnosis of ovarian tumors.

Method

Seventy-five women scheduled for surgical removal of adnexal masses were assessed by transvaginal ultrasound. Ovarian tumors were classified by IOTA simple rules and two three-dimensional blocks were recorded. In a second step analyses, a 4 cm³ spherical sample was obtained from the highest vascularized solid area of each stored block. Vascularization index (VI), flow index (FI) and vascularization-flow index (VFI) were calculated. The repeatability was assessed by concordance correlation coefficient (CCC) and limits of agreement (LoA), and diagnostic accuracy by area under ROC curve.

Results

IOTA simple rules classified 26 cases as benign, nine as inconclusive and 40 as malignant. There were eight false positive and no false negative. Among the masses classified as inconclusive or malignant by IOTA simple rules, the CCCs were 0.91 for VI, 0.70 for FI, and 0.86 for VFI. The areas under ROC curve were 0.82 for VI, 0.67 for FI and 0.81 for VFI.

Conclusions

3D-PD angiography presented considerable intraobserver variability and low accuracy for identifying false positive results of IOTA simple rules.

Performance of three-dimensional power Doppler angiography as third-step assessment in differential diagnosis of adnexal masses

OBJECTIVE

To evaluate the contribution of three-dimensional (3D) power Doppler angiography (3D-PDA) to the differential diagnosis of adnexal masses.

METHODS

This was a prospective study in women diagnosed with a persistent adnexal mass and subsequently scheduled for surgery in a tertiary university hospital. All women were evaluated by transvaginal/transrectal ultrasound according to a predetermined three-step protocol, with transabdominal ultrasound being performed in some cases. First, morphological evaluation of the mass was performed using gray-scale 'pattern recognition' (first step). Lesions diagnosed as having a benign pattern were considered as being at low risk of malignancy whereas tumors with solid components, ascites and/or signs of carcinomatosis were considered as being at high risk of malignancy. In both cases no further test was performed and a decision regarding clinical management, either for follow-up or surgery, was taken. Tumors with solid components but without signs of ascites or carcinomatosis were considered as being at intermediate risk of malignancy. These lesions were assessed by two-dimensional (2D) PDA to evaluate tumor vascularity (color score) (second step). Solid tumors with a color score of 1 or 2 were considered as benign and no further test was performed, while tumors with a color score of 2, 3 or 4 within solid components or a color score of 3 or 4 in the case of a solid tumor were considered as malignant. The latter group underwent 3D-PDA assessment (third step). Vascularization index (VI) was calculated in a 1-mL sphere of the most vascularized area of the tumor. When a VI ≥ 24.015% was found, the tumor was considered as malignant. All masses were removed surgically and definitive histological diagnosis was used as the gold standard. Sensitivity and specificity for each strategy were calculated and compared. In the case of bilateral tumors, only the more suspicious one was used for analysis.

RESULTS

A total of 367 adnexal masses diagnosed in 367 women (mean age, 46.5 (range, 18-80) years) were evaluated during the study period. Of these, 86 masses were malignant and 281 were benign. The sensitivity and specificity for each assessment strategy were as follows: one-step, 97.7% and 78.6%; two-step, 94.2% and 97.9% (P < 0.001 for specificity when compared with that of one-step); three-step, 90.7% and 98.9% (not statistically significant when compared with that of two-step).

CONCLUSIONS

The addition of 2D-PDA in the differential diagnosis of an adnexal mass significantly increases specificity while sensitivity remains high; however performing subsequent 3D-PDA does not provide additional information or further improve diagnostic performance subsequent to 2D-PDA.

Role of Three-Dimensional Ultrasound in Gynecology

Three-dimensional ultrasound (3D USG) is a fast-evolving imaging technique that holds a great potential for use in gynecology. Its sensitivity and specificity is reported to be close to 100 % for diagnosing congenital uterine anomalies, comparable with those of magnetic resonance imaging (MRI) and laparoscopy. With 3D USG, a coronal view of the uterus can be obtained, clearly outlining the external contour of the uterus and providing accurate information about the shape of the cavity. Although 3D USG may not perform well in thin endometria, combining it with saline infusion sonography (SIS) overcomes this problem. Research shows that 3D USG is more sensitive and specific than two-dimensional ultrasound (2D USG) in defining and mapping uterine lesions, such as fibroids, adenomyosis, and intrauterine synechia. In cases of suspected malignancy, 3D USG is mainly used in the initial evaluation of patients. Measuring various indices and mapping vascular architecture with 3D power Doppler have been proposed for evaluating adnexal masses. Although some studies raised hope, no consensus is reached about its use, success, and limitations. In urogynecology, translabial 3D USG is proved to be a valuable tool, as it provides instant access to the axial plane, which clearly depicts the relationship of the vagina, urethra, rectum, and the muscular pelvic floor. Studies report no significant differences between translabial 3D USG and MRI measurements for evaluation of the pelvic floor. In conclusion, adding 3D USG to routine gynecological workup can be beneficial for clinicians, as it provides fast and accurate results in a relatively cost-effective setting.

[Sonographic diagnosis of presumed benign ovarian tumors]

To discriminate ovarian lesions is of particular importance in gynecological practice. Two main problems need answers: discrimination of benign and malignant adnexal masses and choice of the appropriate surgical treatment if necessary. Nearly 2% of the adnexal masses are ovarian carcinomas or borderline tumors. It is now, well established that ultrasonography is the gold standard for ovarian cyst diagnosis. The purpose of this data was to review the literature and to establish, with the evidence base medicine model, which parameters and existing diagnostic models using ultrasound and Doppler perform best in the evaluation of adnexal masses. Transvaginal sonography has demonstrated considerable advantage over conventional transabdominal sonography. However, transparietal sonography is still useful in large tumors. Definition of the nomenclature and classification was done and should be used. Unilocular ovarian cyst characterization seems easy using sonography and Doppler. In front of complication, discrimination of such functional cyst may be difficult but spontaneous regression confirms usually the expectative management. Dermoid cysts and endometriomas seem to be easier to discriminate from other adnexal masses. Ultrasound and morphologic parameters have a sensitivity of about 90% and a specificity of 80%; that makes this exam the gold standard for ovarian masses diagnosis. Only 50% of ovarian masses are characterized by sonography. Scoring systems help to differentiate benign from malignant masses (sensitivity of about 90%). Logistic regression and models are good methods especially for LR1 and 2 and RMI and may be useful for malignancy prediction but are difficult to use in current practice. Expert diagnosis is a subjective but most important performing parameter. Any suspicious ovarian mass or not easily diagnosed mass requires sonography by an expert, which can first use all the techniques and the different parameters to discriminate benign and malignant tumors. An explicit report will help the physician to define the right attitude for an appropriate management. Six to 16% of adnexial masses are complex or not classified and will result in MRI prescription or surgery.

Does three-dimensional power Doppler ultrasound predict histopathological findings of uterine fibroids? A preliminary study

OBJECTIVES

To compare three-dimensional (3D) power Doppler sonographic characteristics of fibroids with histopathological parameters.

METHODS

We evaluated sonographically 73 fibroids before myomectomy or hysterectomy. For each, the total fibroid volume, a shell of 3 mm and a 1-cm(3) spherical sample from the most vascularized area on subjective assessment were captured. 3D power Doppler vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were generated in the acquired volumes. The degree of cellularity, ischemic necrosis and fibrosclerosis, as well as CD31 and Ki-67 staining for vascular density and proliferation index, respectively, were estimated using the surgical sample. Pathological data were considered as dependent variables and ultrasound data as independent variables in multivariable logistic regression models including patients' characteristics.

RESULTS

A high histological 'cellular activity score', combining hypercellularity, a fibrosclerosis rate < 25% and positive Ki-67 staining, was statistically related in multivariate analyses to high 3D power Doppler VI in spherical samples (odds ratio (OR), 1.1 (95% CI, 1.0-1.3), P < 0.05) and VFI (OR, 1.3 (95% CI, 1.0-1.8), P < 0.05). Positive CD31 staining was statistically related to high 3D power Doppler VI in spherical samples (OR, 1.1 (95% CI, 1.0-1.3), P < 0.05). In contrast, ischemic necrosis was statistically related to low 3D power Doppler VI in the total volume (OR, 0.6 (95% CI, 0.4-1.0), P < 0.05) and VFI (OR, 0.4 (95% CI, 0.1-1.1), P < 0.05).

CONCLUSION

Vascular density, ischemic necrosis and histological cellular activity score are statistically significantly associated with some 3D power Doppler indices.

Does sphere volume affect the performance of three-dimensional power Doppler virtual vascular sampling for predicting malignancy in vascularized solid or cystic-solid adnexal masses?

OBJECTIVE

To assess whether, when using spherical sampling with Virtual Organ Computer-Aided Analysis (VOCAL) for calculating three-dimensional (3D) power Doppler angiography (PDA) indices, the sphere volume affects performance in the prediction of malignancy in vascularized cystic-solid or solid adnexal masses.

METHODS

One hundred and thirty-eight women (mean +/- SD age, 51.8 +/- 14.1 years) diagnosed as having vascularized cystic-solid or solid adnexal masses on B-mode and two-dimensional (2D) power Doppler ultrasound were evaluated by 3D-PDA prior to surgery. Five women had bilateral masses, giving a total number of 143 masses analyzed. Vascularization was assessed using VOCAL software. 3D-PDA vascular indices (vascularization index (VI), flow index (FI) and vascularization flow index (VFI)) from the most vascularized area within papillary projections and solid areas were calculated automatically using spherical sampling. Five different volumes of sphere were used (1 cm(3), 2 cm(3), 3 cm(3), 4 cm(3) and 5 cm(3)) in each case. A definitive histological diagnosis was obtained in each case after surgical tumor removal.

RESULTS

One hundred and seventeen (82%) masses were malignant and 26 (18%) were benign. Morphological evaluation revealed 34 (24%) unilocular solid masses, 49 (34%) multilocular solid masses and 60 (42%) mostly solid masses. The 1-cm(3) sphere could be used in 100% of the cases, the 2-cm(3) sphere could be used in 98.2% of the cases and the 3-5-cm(3) spheres could be used in 97.2% of the cases. The median VI, FI and VFI for all sphere volumes were significantly higher in malignant compared with non-malignant tumors. Receiver-operating characteristics curve analysis showed that VI and VFI, independently of sphere volume, were better predictors of malignancy than was FI. The best cut-off values for the 3D-PDA indices differed depending on sphere volume. VI was significantly more specific than were VFI and FI.

CONCLUSIONS

Sphere volume does not affect the performance of 3D-PDA. We recommend the use of different cut-off values for 3D-PDA indices for discriminating between benign and malignant adnexal masses, depending on the sphere volume used. Use of VI is preferable due to its higher specificity.

Three-dimensional power Doppler angiography of cyclic ovarian blood flow

OBJECTIVE

The purpose of this study was to assess the vascular indices generated by 3-dimensional (3D) power Doppler angiography by evaluating the cyclic changes in the vascularity of normal ovaries, including those that were ovulating, nonovulating, and hormonally suppressed.

METHODS

In this prospective longitudinal observational study, a cohort of premenopausal regularly menstruating women with no known ovarian disease underwent 3D power Doppler imaging every 2 to 3 days for the duration of 1 menstrual cycle. Four indices were generated: vascularization index (VI), flow index (FI), vascularization-flow index (VFI), and mean grayness. Comparisons of vascularity were made between ovulating, nonovulating, and hormonally suppressed ovaries. Normal ranges were established and graphed longitudinally.

RESULTS

Eighteen participants (36 ovaries) ages 28 to 45 years underwent an average of 10 examinations, yielding 368 acquired ovarian volumes for analysis. Seven participants used hormonal contraception. The VI, FI, and VFI were closely correlated (Pearson product moment correlation coefficients, 0.52-0.95). The vascular indices of ovulating ovaries were significantly higher than those of nonovulating ovaries (VI, FI, and VFI, all P < .001), with the largest discrepancies during the luteal phase. Hormonally suppressed ovaries had significantly lower vascularity throughout the cycle (VI, P < .002; FI, P < .001; VFI, P < .007). The vascular indices of all groups appeared to drop during the late follicular period and then rise again.

CONCLUSIONS

The VI would suffice as the principal vascular parameter for 3D power Doppler analysis. Preovulatory scans may be more useful for distinguishing pathologic vascularization. Hormonally suppressed ovaries have significantly lower vascularity throughout the cycle. Normal-appearing ovaries with vascular indices above the normal ranges established by these data may warrant further investigation.

Three-dimensional power Doppler vascular sonographic sampling for predicting ovarian cancer in cystic-solid and solid vascularized masses

OBJECTIVE

The purpose of this study was to explore the role of 3-dimensional (3D) power Doppler (PD) sonography to discriminate between benign and malignant cystic-solid and solid vascularized adnexal masses and to define cutoff values for 3D PD indices to be used in a clinical setting.

METHODS

A total of 143 consecutive women (mean age, 50.4 years; range, 17-82 years) with diagnoses of cystic-solid or solid vascularized adnexal masses on B-mode and 2-dimensional PD sonography were evaluated by 3D PD sonography before surgery. Three-dimensional PD sonography was used to assess vascularization within papillary projections and solid areas with a virtual organ computer-aided analysis program. Three-dimensional PD vascular indices (vascularization index [VI], flow index [FI], and vascularization-flow index [VFI]) were automatically calculated. A definitive histologic diagnosis was obtained in each case.

RESULTS

A total of 113 masses (74%) were malignant, and 39 (26%) were benign. Morphologic evaluation revealed 30 unilocular solid masses (19.7%), 43 multilocular solid masses (28.3%), and 79 mostly solid masses (52%). The mean VI (9.365% versus 3.3%; P< .001), FI (34.318 versus 28.794; P< .001), and VFI (3.233 versus 1.15; P<0.01) were significantly higher in malignant tumors. No differences were found in the resistive index, pulsatility index, and peak systolic velocity. Receiver operating characteristic analysis revealed an area under the curve of 0.77 (95% confidence interval, 0.69-0.85), 0.71 (0.60-0.81), and 0.75 (0.66-0.83) for the VI, FI and VFI, respectively. For reducing the false-positive rate by almost one-third, sensitivity values for the VI (cutoff, 1.556%), FI (25.212), and VFI (0.323) were 92%, 95%, and 93%, respectively.

CONCLUSIONS

Three-dimensional PD vascular indices could be helpful for reducing the false-positive rate in cystic-solid and solid vascularized adnexal masses.