A comparison of intratumoural indices of blood flow velocity and impedance for the diagnosis of ovarian cancer

Validity of ultrasound with color Doppler to differentiate between benign and malignant ovarian tumours

OBJECTIVE

To assess the utility of ultrasound and color Doppler and the Accuracy of International Ovarian Tumor Analysis (IOTA) group classification in the preoperative evaluation of ovarian neoplasms to assess benign or malignant histopathology in the diagnosis of ovarian tumors.

METHODS

This observational longitudinal prospective analysis of 60 patients was performed over a period of 2 years (2017- 2019). The mean age of the patients was 43.75 years. Ultrasonography of ovarian masses were evaluated, and cancer antigen-125 (CA-125) levels were evaluated. Based on the IOTA classification, the B and M features of adnexal masses were studied. Color Doppler imaging was performed to evaluate the patterns of vascularity and indices.

RESULTS

Sixty patients with 35 benign, 23 malignant, and two borderline lesions were included in the study. In malignant lesions, 17 women (73.9%) were above the age of 45. The CA-125 cut off was ≥35 internatioal units/mL. Based on the IOTA classification, 27/35 (77.1%) benign cases, were correctly identified as benign, 6/35 (17.1%) benign cases were incorrectly identified as malignant, and two (5.7%) were found to be inconclusive. In the malignant group, 17 of the 23 patients were identified as having malignancy. Color Doppler showed three (18.8%) benign tumors had a pulsatality index (PI) of <0.8 and 21 malignant tumors had a PI of <0.8. Four benign tumors had an resistive index (RI) of <0.6 and 100% of malignant tumors had an RI <0.6.

CONCLUSION

The IOTA classification is a reliable scoring system for adnexal masses, and color Doppler can help to minimize interobserver variation.

A 96-well microplate bioreactor platform supporting individual dual perfusion and high-throughput assessment of simple or biofabricated 3D tissue models

Traditional 2D monolayer cell cultures and submillimeter 3D tissue construct cultures used widely in tissue engineering are limited in their ability to extrapolate experimental data to predict in vivo responses due to their simplistic organization and lack of stimuli. The rise of biofabrication and bioreactor technologies has sought to address this through the development of techniques to spatially organize components of a tissue construct, and devices to supply these tissue constructs with an increasingly in vivo-like environment. Current bioreactors supporting both parenchymal and barrier tissue constructs in interconnected systems for body-on-a-chip platforms have chosen to emphasize study throughput or system/tissue complexity. Here, we report a platform to address this disparity in throughput and both system complexity (by supporting multiple in situ assessment methods) and tissue complexity (by adopting a construct-agnostic format). We introduce an ANSI/SLAS-compliant microplate and docking station fabricated via stereolithography (SLA), or precision machining, to provide up to 96 samples (Ø6 × 10 mm) with two individually-addressable fluid circuits (192 total), loading access, and inspection window for imaging during perfusion. Biofabricated ovarian cancer models were developed to demonstrate the in situ assessment capabilities via microscopy and a perfused resazurin-based metabolic activity assay. In situ microscopy highlighted flexibility of the sample housing to accommodate a range of sample geometries. Utility for drug screening was demonstrated by exposing the ovarian cancer models to an anticancer drug (doxorubicin) and generating the dose-response curve in situ, while achieving an assay quality similar to static wellplate culture. The potential for quantitative analysis of temporal tissue development and screening studies was confirmed by imaging soft- (gelatin) and hard-tissue (calcium chloride) analogs inside the bioreactor via spectral computed tomography (CT) scanning. As a proof-of-concept for particle tracing studies, flowing microparticles were visualized to inform the design of hydrogel constructs. Finally, the ability for mechanistic yet high-throughput screening was demonstrated in a vascular coculture model adopting endothelial and mesenchymal stem cells (HUVEC-MSC), encapsulated in gelatin-norbornene (gel-NOR) hydrogel cast into SLA-printed well inserts. This study illustrates the potential of a scalable dual perfusion bioreactor platform for parenchymal and barrier tissue constructs to support a broad range of multi-organ-on-a-chip applications.

Estimation of probability of malignancy using a logistic model combining color Doppler ultrasonography, serum CA125 level in women with a pelvic mass

The goal of this study was to develop a scoring system using combination of Doppler characterization of pelvic/ovarian lesions and serum CA125 level. Our purpose was to maximize the preoperative discrimination between benign and malignant entities. In a prospective study, a total of 101 patients were evaluated preoperatively using a standard transvaginal ultrasound and color Doppler imaging with pulse spectral analysis and serum CA125 level within a week prior to surgery. The variables that were analyzed by the multivariate logistic regression method are as follows: tumor structure, ascites, presence of septum, the peak systolic velocity (PSV), the resistance index (RI), and serum CA125 level. Of the 101 patients qualified for the study, 48 patients were diagnosed with benign (47.5%) and 53 (52.5%) with malignant tumors. Each criterion used alone provides statistically significant discrimination between benign and malignant tumors. Four criteria could be combined in a malignancy score which is calculated using the product of the serum CA125 level (1 if CA125 > or =40 U/mL and 0 if CA125 <40 U/mL), the result of sonography for presence of septum in tumor (1 if there was septum > or =3 mm, 0 if there was no septum or <3 mm), result of Doppler flow imaging as RI (1 if RI < or =0.5 and 0 if RI >0.5) and the PSV (1 if PSV > or =40 cm/s and 0 if PSV <40 cm/s). This scoring system devised was statistically more effective discriminator between cancer and benign lesions than formal methods. Using malignancy score cutoff level of two, the sensitivity was 98% (CI 88.62-99.9.), the specificity was 85% (CI 71.62-93.45), the positive predictive value was 87.5%, and the negative predictive value was 97.6%. Area under curve of receiver operative characteristic curves was 0.987 (CI 0.971-1.004). These values were statistically more significant than those obtained from the independent use of RI, PSV, or serum CA125 level at their optimum decision values (P < 0.05). There is a need for a prospective evaluation of this score using a larger sample of patients.

Power Doppler vascularity index for predicting malignancy of adnexal masses

OBJECTIVE

To assess the performance of a power Doppler vascularity index in the preoperative diagnosis of ovarian malignancy.

METHODS

Adnexal masses (n = 101) were examined prospectively with power Doppler ultrasonography before surgical treatment. The tumor vascularity index (power Doppler index, PDI) was determined by quantification of the number of pixels in a defined region of interest according to the formula: number of colored pixels/(total number of pixels minus the number of pixels in the fluid or avascular areas). It was estimated on selected frames of the tumors using an in-house color-quantifying program added to MATLAB 6.0 software. Inter- and intraobserver reproducibilities of PDI assessment were evaluated. Intratumoral blood flow velocity waveforms were obtained to determine the lowest resistance index (RI). A subjective visual score of power Doppler signals in the tumor was used to classify it as having low, moderate or high vascularity. The discriminatory ability of this score was compared to that of RI and PDI measurement.

RESULTS

Histology identified 23 malignant and 78 benign lesions. The PDI was considerably higher in malignant than in benign lesions (0.34 +/- 0.04 vs. 0.12 +/- 0.06; P < 0.001). The intra- and interobserver variabilities of PDI were low (intraclass correlation coefficients of 0.99 and 0.97, respectively). The PDI cut-off value to differentiate malignant from benign tumors was set at 0.265 (26.5% of the tumor being colored). Using this cut-off, sensitivity and specificity were 100% (95% CI, 87.8-100.0) and 97.4% (95% CI, 91.0-99.7) compared to 78.3% (95% CI, 56.3-92.5) and 83.1% (95% CI, 72.9-90.7) for RI (cut-off value of 0.53) and 78.3% (95% CI, 56.3-92.5) and 94.9% (95% CI, 87.4-98.6) for visual scoring. Logistic regression demonstrated that PDI was the best parameter for differentiating between malignant and benign tumors.

CONCLUSION

The power Doppler vascularity index obtained using customized color quantifying software has high diagnostic value in discriminating between benign and malignant adnexal masses.

Color Doppler energy prediction of malignancy in adnexal masses using logistic regression models

OBJECTIVE

The aim of this study was to assess the usefulness of color Doppler energy in the preoperative diagnosis of ovarian malignancy using multivariate logistic regression analysis.

METHODS

One hundred and thirty adnexal masses were studied with transvaginal B-mode, color energy, and pulsed Doppler ultrasonography before surgery in order to develop a model that could be used to determine malignancy. Each ultrasonographic variable (tumor size, wall thickness, septal structure, echogenicity, papillary projection, density (solid or not)) was included individually or combined together as part of the Sassone ultrasound score. Intratumoral blood flow velocity waveforms were obtained to determine pulsatility index and resistance index and a more subjective parameter, location of tumor vascularity, was also assessed. Menopausal status and serum CA 125 levels were also entered as categorical variables. Sonographic parameters were entered alone, then associated with menopausal status and CA 125 serum levels, and finally with Doppler energy measurements. Our model was then validated in a group of 68 adnexal masses and compared to the model of Alcazar.

RESULTS

Eighteen adnexal masses (13.8%) were malignant or of low malignant potential. Multivariate analysis showed that papillary projection of the tumor wall, cyst with solid parts, resistance index with a cut-off value of 0.53, CA 125, and central blood flow location, were the only factors to be independent predictors of malignancy. Menopausal status was not an independent factor. For the final model including the Doppler energy parameter the best sensitivity and specificity were 83% and 93%, respectively, at a cut-off value of 10% probability of malignancy compared to 83% and 87% for the morphological variables alone. Validation of the model showed its diagnostic performance to be as good as that reported in the original population and better than the model of Alcazar.

CONCLUSION

Sonographic analysis of adnexal masses including color Doppler energy shows the best predictive properties according to histological diagnosis, and improves preoperative diagnosis of malignancy.

Gynecologic ultrasound

For most women, pelvic sonography using a transvaginal probe is the imaging modality of choice for evaluating the uterus and adnexae. It is reliable for detecting ovarian cysts and other adnexal masses, and it can often determine if a lesion can be observed on serial examinations or if it requires more urgent attention. Uterine ultrasound is reliable for evaluating both the normal and abnormal endometrium and myometrium. In cases that are technically limited, or in those that are difficult to interpret, a tailored MR imaging examination often can be helpful.

US characterization of ovarian masses: a meta-analysis

PURPOSE

To compare the effectiveness of current ultrasonographic (US) techniques for characterizing ovarian masses.

MATERIALS AND METHODS

Through a MEDLINE literature search, articles with imaging-histopathologic correlation and data that allowed calculation of contingency tables were identified. Results of morphologic assessment, Doppler US, color Doppler flow imaging, and combined techniques were compared.

RESULTS

Among 89 data sets from 46 included studies (5,159 subjects), 35 sets used morphologic information, 36 measured Doppler US indexes, 10 assessed tumor vascularity with color Doppler flow imaging, and eight used combined techniques. Summary receiver operating characteristic curves revealed significantly higher performance for combined techniques than for morphologic information (P: =.003), Doppler US indexes (P: =.003), or color Doppler flow imaging alone (P: =.001). The Q* point (and 95% CI) for combined techniques was 0.92 (0.87, 0.96) versus 0. 85 (0.83, 0.88) for morphology, 0.82 (0.78, 0.86) for Doppler US, and 0.73 (0.58, 0.87) for color Doppler flow imaging. Morphologic assessment showed a trend toward better performance than color Doppler flow imaging (P: =.09) or Doppler US indexes (P: =.07). Doppler US index results were better in earlier studies (P: =.005).

CONCLUSION

Combined US techniques and a diagnostic algorithm perform significantly better than morphologic assessment, color Doppler flow imaging, or Doppler US indexes alone in characterizing ovarian masses.

Pelvic Doppler

This article reviews gray-scale and Doppler evaluation of the adexae and endometrium. Color Doppler is useful in distinguishing between cystic and solid masses. However, spectral Doppler is of limited utility in improving the gray-scale morphologic impression of a mass being either benign or malignant.

Sonographic prediction of malignancy in adnexal masses using an artificial neural network

OBJECTIVE

To generate a neural network algorithm which computes a probability of malignancy score for pre-operative discrimination between malignant and benign adnexal tumours.

DESIGN

A retrospective analysis of previously collected data. Information from 75% of the study group was used to train an artificial neural network and the remainder was used for validation.

SETTING

The Gynaecological Ultrasound Research Unit at King's College Hospital, London.

POPULATION

Sixty-seven women with known adnexal mass who had been examined using transvaginal B-mode ultrasonography and colour Doppler imaging with pulse spectral analysis immediately before surgery. The excised masses were classified histologically as benign (n = 52) or malignant (n = 15), of which three were borderline.

METHODS

The variables that were put into the artificial neural network were: age, menopausal status, maximum tumour diameter, tumour volume, locularity, the presence of papillary projections, the presence of random echogenicity, the presence of analysable blood flow velocity waveforms, the peak systolic velocity, time-averaged maximum velocity, the pulsatility index, and resistance index. Histological classification, categorised as benign or malignant, was the output result.

RESULTS

A variant of the back propagation method was selected to train the network. The overall architecture of the network with the best performance contained an input layer with four variables (age, time-averaged maximum velocity, papillary projection score and maximum tumour diameter), a hidden layer with three units and an output layer with one. The sensitivity and specificity at the optimum diagnostic decision value for the artificial neural network output (0.45) were 100% (95% CI 78.2%-100%) and 98.1% (95% CI 89.5%-100%), respectively. These values were significantly better than those obtained from the independent use of the resistance index, pulsatility index, time-averaged maximum velocity or peak systolic velocity at their optimum decision values (P < 0.01).

CONCLUSION

Artificial neural networks may be used on clinical and ultrasound derived end-points to accurately predict ovarian malignancy. There is a need for a prospective evaluation of this technique using a larger number of patients.

A multivariate logistic regression analysis in predicting malignancy for patients with ovarian tumors

OBJECTIVE

Our objective was to improve the preoperative diagnosis of ovarian malignancy using a multivariate logistic regression analysis on the basis of demographic, serologic, gray-scale morphological, and Doppler variables.

METHODS

One hundred seventy-one patients with ovarian tumors (120 benign, 51 malignant including 9 tumors of low malignant potential) were studied with transvaginal B-mode, color, and pulsed Doppler ultrasonography before surgery. Based on the gray-scale ultrasound imaging, each tumor was classified as a unilocular cyst, multilocular cyst, unilocular cyst with solid parts, multilocular cyst with solid parts, or solid tumor. Intratumoral blood flow velocity waveforms were recorded on all tumors except unilocular cyst and were evaluated for resistance index (RI) and peak systolic velocity (PSV). Serum CA 125 levels were also measured.

RESULTS

Twenty tumors were unilocular cysts and were all benign. Seventy tumors including all unilocular cysts which showed no flows were all benign. The remaining 101 tumors (50 benign, 51 malignant including 9 tumors of low malignant potential) presented intratumoral blood flows. Univariate and multivariate logistic regression analyses were conducted to identify variables predictive of ovarian malignancy in these 101 tumors. The variables included age, menstrual state, serum CA 125 levels, B-mode classification, RI, and PSV. In univariate analysis, menopause, the positivity of CA 125 (> or = 35 U/ml), and PSV larger than or equal to 10.4 cm/s were found to be significantly associated with malignant tumors. The PSV value of 10.4 cm/s was the median in benign tumors. Multivariate analysis showed that serum CA 125 levels (> or = 35 U/ml) (P = 0.002) and PSV (> or = 10.4 cm/s) (P < 0.001) were to be independent predictors of malignancy.

CONCLUSION

These results suggest that intratumoral PSV is the strongest means of differentiating benign from malignant ovarian tumors with suspicious gray-scale ultrasonographic findings.

Screening strategies for ovarian cancer

Alternative procedures have been proposed for the detection of early ovarian cancer in asymptomatic women. Transvaginal ultrasonography, with or without colour Doppler imaging and intra-tumoural blood flow analysis, is used as the definitive technique in all current screening programmes. Target populations for clinical trials are recruited on the basis of risk factors for the disease (e.g. age or postmenopausal status, family history of ovarian cancer). Whether or not a participant is scanned may depend on results from the immunoassay of tumour antigens in peripheral serum, or from pedigree analysis. New developments include the use of: (i) intra-tumoural blood velocity as an end-point of colour Doppler imaging, (ii) serial measurements of serum tumour antigens to identify women for ultrasonography, and (iii) tests which detect regionally clustered germ-line BRCA1 mutations. More research is required to assess the beneficial and adverse effects of the new strategies.

Association of thymidine phosphorylase concentration with ultrasound-derived indices of blood flow in ovarian masses

BACKGROUND

The aim of this study was to determine the relationship between the concentration of thymidine phosphorylase (a known angiogenic factor) and indices of blood flow in physiologic ovarian tissues and overt (benign and malignant) tumors.

METHODS

The ovaries of all patients were examined by transvaginal ultrasonography, with color Doppler imaging and pulsed Doppler spectral analysis, within the 24 hours preceding laparotomy. Ovaries removed at surgery were dissected into their main components (follicles, corpus luteum, and tumor) and, where possible, into areas of high blood velocity according to the results of color Doppler imaging. The concentration of thymidine phosphorylase was measured by an enzyme-linked immunosorbent assay.

RESULTS

Thirty-eight tissue aliquots (16 from normal ovaries and 22 from ovarian tumors) were obtained from 33 patients. Twenty-nine tissue samples (76%) came from areas of measurable (high) blood velocity. The concentration of thymidine phosphorylase was significantly higher in tissue associated with high blood velocity (median 17.9, range 1.8-78.3 units per mg of protein vs. median 6.8, range 1.3-24.7 units per mg of protein, respectively; P < 0.05, Mann-Whitney U test). All of 8 corpora lutea, 12 of 14 benign tumors, and 7 of 7 malignant tumors had measurable blood velocity. There was a significant correlation between the concentration of thymidine phosphorylase and the peak systolic velocity in benign tumors (correlation coefficient [r] = 0.79, P < 0.01) and malignant tumors (r = 0.87, P < 0.05).

CONCLUSIONS

High intratumoral peak systolic velocity as determined by transvaginal color Doppler imaging and spectral analysis reflects high production of thymidine phosphorylase. This finding may aid the development of antivascular therapy for patients with ovarian carcinoma.