Scholarly article on topic 'Three-dimensional power Doppler indices of ovarian stromal blood flow and serum vascular endothelial growth factor after laparoscopic ovarian drilling in women with polycystic ovary syndrome'

Three-dimensional power Doppler indices of ovarian stromal blood flow and serum vascular endothelial growth factor after laparoscopic ovarian drilling in women with polycystic ovary syndrome Academic research paper on "Health sciences"

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Abstract of research paper on Health sciences, author of scientific article — Mohammed T. Gad Al-Rab, Abdel-Baset F. Mohammed, Mo’men M. Hassan, Mohammed A. Razek

Abstract Objective To evaluate the effects of laparoscopic ovarian drilling (LOD) on three-dimensional (3D) power Doppler indices of ovarian stromal blood flow and serum vascular endothelial growth factor (VEGF) levels in women with polycystic ovary syndrome (PCOS). Design Prospective controlled study. Setting Minia University Hospital, Minia, Egypt. Material and methods 30 clomiphene citrate resistant women with PCOS undergoing LOD and 30 fertile women with normal ovaries were recruited in this study. Hormonal profile, Doppler indices of ovarian stromal blood flow and serum VEGF assays before and after LOD were evaluated and compared between the two groups. Evaluation was done at the beginning of the study, 1 week after LOD and at 3 and 6 month follow up periods. Main outcome measures 3-D power Doppler indices of both ovaries and serum VEGF concentration. Results Before LOD, serum levels of VEGF, total testosterone (T), free androgen index (FAI), LH, LH:FSH ratio, total antral follicle count (AFC), total ovarian volume (OV) and the 3D power Doppler blood flow indices were significantly higher in the PCOS group than in the control group. After LOD, there was a significant reduction in the serum levels of VEGF, T, sex-hormone binding globulin (SHBG), FAI, LH, LH:FSH ratio, AFC, OV and the 3D power Doppler indices and remained all low at 3 and 6month follow up. There were significant positive correlations between power Doppler flow indices (VI, FI, and VFI) with serum VEGF, total T, and LH before and after LOD. Conclusions Serum VEGF and ovarian blood flow indices were higher in women with PCOS than in normal women. LOD reduced serum levels of VEGF, in addition to ovarian blood flow indices, in women with PCOS.

Academic research paper on topic "Three-dimensional power Doppler indices of ovarian stromal blood flow and serum vascular endothelial growth factor after laparoscopic ovarian drilling in women with polycystic ovary syndrome"

Middle East Fertility Society Journal (2014) xxx, xxx-xxx

Middle East Fertility Society Middle East Fertility Society Journal

www.mefsjournal.org www.sciencedirect.com

ORIGINAL ARTICLE

Three-dimensional power Doppler indices of ovarian stromal blood flow and serum vascular endothelial growth factor after laparoscopic ovarian drilling in women with polycystic ovary syndrome

Mohammed T. Gad Al-Rab b, Abdel-Baset F. Mohammed a *, Mo'men M. Hassan b, Mohammed A. Razek b

a Department of Obstetrics & Gynecology, Faculty of Medicine, El-Minia University, El-Minia, Egypt b Department of Clinical Pathology, Faculty of Medicine, El-Minia University, El-Minia, Egypt

Received 23 January 2014; revised 1 April 2014; accepted 10 April 2014

KEYWORDS

Ovarian drilling; VEGF;

Doppler indices

Abstract Objective: To evaluate the effects of laparoscopic ovarian drilling (LOD) on three-dimensional (3D) power Doppler indices of ovarian stromal blood flow and serum vascular endo-thelial growth factor (VEGF) levels in women with polycystic ovary syndrome (PCOS).

Design: Prospective controlled study.

Setting: Minia University Hospital, Minia, Egypt.

Material and methods: 30 clomiphene citrate resistant women with PCOS undergoing LOD and 30 fertile women with normal ovaries were recruited in this study. Hormonal profile, Doppler indices of ovarian stromal blood flow and serum VEGF assays before and after LOD were evaluated and compared between the two groups. Evaluation was done at the beginning of the study, 1 week after LOD and at 3 and 6 month follow up periods.

Main outcome measures: 3-D power Doppler indices of both ovaries and serum VEGF concentration.

Results: Before LOD, serum levels of VEGF, total testosterone (T), free androgen index (FAI), LH, LH:FSH ratio, total antral follicle count (AFC), total ovarian volume (OV) and the 3D power Doppler blood flow indices were significantly higher in the PCOS group than in the control group. After LOD, there was a significant reduction in the serum levels of VEGF, T, sex-hormone binding

Corresponding author. Address: Hamad Medical Corporation, Women Hospital, Department of Obstetrics and Gynecology, P.B. 3050, Doha, Qatar. Tel.: +974 55458229. E-mail address: abdu163@hotmail.com (A.-B.F. Mohammed). Peer review under responsibility of Middle East Fertility Society.

1110-5690 © 2014 Production and hosting by Elsevier B.V. on behalf of Middle East Fertility Society. http://dx.doi.org/10.1016/j.mefs.2014.04.007

globulin (SHBG), FAI, LH, LH:FSH ratio, AFC, OV and the 3D power Doppler indices and remained all low at 3 and 6 month follow up. There were significant positive correlations between power Doppler flow indices (VI, FI, and VFI) with serum VEGF, total T, and LH before and after LOD.

Conclusions: Serum VEGF and ovarian blood flow indices were higher in women with PCOS than in normal women. LOD reduced serum levels of VEGF, in addition to ovarian blood flow indices, in women with PCOS.

© 2014 Production and hosting by Elsevier B.V. on behalf of Middle East Fertility Society.

1. Introduction

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder. It affects 5-10% of women of reproductive age and at least 75% of cases with anovulatory infertility. It is characterized by a marked increase in preantral follicle number arranged peripherally around a dense core of stroma or scattered throughout an increased amount of stroma. This is associated with menstrual disturbance, hyperandrogenism, and anovulation (1-4).

Laparoscopic ovarian drilling (LOD) is currently the method of choice to treat anovulatory women with PCOS resistant to clomiphene citrate (CC) (5). LOD causes minimal morbidity, precludes the need to monitor cycles, and has a low risk of multiple pregnancies. A reduction has been observed in the incidence of ovarian hyperstimulation syndrome (OHS) after LOD. This may be an advantage for women with PCOS who will receive gonadotropins for IVF (6).

Ovarian stromal blood flow can be assessed by both color Doppler and power Doppler ultrasound. The power Doppler technique is more sensitive (7). Ovarian stromal blood flow abnormalities in PCOS have been previously described (8,9). Ovarian stromal peak systolic blood flow velocity and time-averaged maximum velocity were found to be significantly greater in women with PCOS than in infertile women with healthy ovaries (10).

Vascular endothelial growth factor (VEGF) not only mediates angiogenesis but also induces connective tissue stromal growth by increasing microvascular permeability. Increased expression of VEGF has been described in the hyperthecotic stroma of polycystic ovaries; in addition, higher serum concentrations of VEGF have been found in women with PCOS than in normal women (11).

There are few studies addressing the effects of LOD on ovarian stromal blood flow using 3D power Doppler ultrasonography in women with PCOS (12-14). Evaluation of ovarian stromal blood flow before and after LOD may be considered a way to study the effects of this therapeutic intervention or the mechanism by which the ovary may respond (15). Therefore, this study was conducted to evaluate the effects of LOD on 3D power Doppler indices of ovarian stromal blood flow and VEGF levels in women with PCOS.

2. Patients and methods

This prospective controlled study was conducted in the department of Obstetrics and Gynecology, Minia University Hospital, Egypt during the period from January 2012 to April 2013 after being accepted by local research committee.

Thirty infertile patients with clomiphene-resistant PCOS and scheduled for LOD were recruited in this study. PCOS was diagnosed according to the 2003 ESHRE/ASRM (Rotterdam criteria) (4). Clomiphene resistance was defined as three consecutive cycles with CC 150 mg daily without ovulation (16). Thirty fertile women with regular menstrual cycle and normal ovaries (by ultrasound examination) were taken as the control group. Women selected for this study were fulfilling the following inclusion criteria: age between 19 and 35 years; primary anovulatory infertility for more than one year; BMI between 20 and 30 kg/m; normal hysterosalpingogram and their partners had normal semen analysis according to WHO criteria (17). Patients with other causes of infertility, organic pelvic diseases at laparoscopy or diseases potentially affecting the ovarian environment and/or function (e.g. endometriosis and leiomyomas), hyperprolactinemia, and those with chronic medical illnesses were excluded from the study. Thorough counseling was given and a written informed consent was obtained from each patient before recruitment in this study.

The recruited patients were subjected to history taking and clinical examination. Hormonal profile, Doppler indices of ovarian stromal blood flow and serum VEGF assays before and after LOD were evaluated and compared between the two groups. Evaluation was done at the beginning of the study, one week after LOD and at 3 and 6 month follow up periods.

All ultrasound examinations were performed using a 3D transvaginal 7.5-MHz power Doppler ultrasound machine (Voluson 530 D; Medison-kretz, Seoul-Zipf, Korea-Austria). All the quantitative measures were taken by experienced gynecologist. To determine the intra-observer error, thirty healthy controls were evaluated by the same operator in this study. During the examination, the Doppler settings were not changed. The region of interest included the whole ovarian region and excluded the supplying vessels. Both ovaries were accessible for evaluation (3-5 cm from the probe). After weighing the total color percentage and flow amplitude in the total volume of interest (18), the VOCAL (virtual organ computer aided analysis) software (Medison-Kretz) for the 3D power Doppler histogram analysis is used to analyze with computer algorithms to form indices of blood flow and vascularization. In brief, as reported by Pairleitner et al. (18), the vascularization index (VI) indicates the proportion of the volume showing a flow signal in the total volume of the ovary. It does not contain any information on the flow signal and intensity. The flow index (FI) is an average of the intensity of flow signal inside the ovary that carries no significance by itself. The vasculariza-tion flow index (VFI) is a combination of the information of vessel presence and amount of flow made by multiplying the FI and VI. During the analysis and calculation, the manual

mode of the VOCAL program was used to cover the whole 3D volume of the ovary. The setting conditions of this study were: Angio Mode: Cent, FRQ, Mid. Frame filter: 3. Line density: 254. Enhance: 3. Far gain: Max 62. Persist: 0.3/0.4. Quality: 12. Density: 6. Enhance: 3. Balance: G > 192. Reject: 79. Two experienced gynecologists analyzed the images independently.

On day 3 of the natural or progestin induced cycle, venous blood samples for hormonal assays were obtained from all patients. In the control group, examination was done in the early follicular phase of any cycle. The following hormones were assessed; follicle stimulating hormones (FSH), luteinizing hormone (LH), total testosterone (T), free androgen index (FAI; T/SHBG X100), dehydroepiandrosterone acetate (DHEAS), sex hormone binding globulin (SHBG) and vascular endothelial growth factor (VEGF). Blood samples (5 ml) were collected in tubes containing EDTA and were immediately centrifuged for 20 min at 1600 rpm, and sera were stored at —70 0C until assayed.

Assays for LH and FSH were performed by automated micro particle enzyme-immunoassay (Abbott Axsym analyzer, Abbott Diagnostics). Assays for SHBG were performed by automated chemiluminescent immunoassay (IMMULITE®; Diagnostic Product Corporation, Los Angeles, CA, USA). The assay used for T was a coated tube radioimmunoassay (Coat-A-Count, Diagnostic Products Corporation). All assays were done according to manufacturer's protocol. The intra-and inter-assay coefficients of variation, respectively, were: LH, 4.5%, 10.4%; FSH, 5.9%, 8.0%; T, 7.5%, 8.0%; and SHBG, 6.8%, 9.4%. Serum VEGF was measured by a quantitative sandwich enzyme immunoassay technique (Quantikine, R&D Systems, Oxon, UK). The minimum detectable VEGF concentration by the assay was 9 pg/ml. The inter-assay coefficients of variation were 8.8%, 7.0% and 6.2% concentrations of 65, 250 and 1003 pg/ml, respectively, whereas the intra-assay coefficients of variation were 6.7%, 4.5% and 5.1% at the concentrations of 54, 235 and 910 pg/ml respectively.

LOD was carried out in the early follicular phase of the menstrual cycle within two weeks from recruitment into this study. Each ovary was cauterized at 4 points, for 4 s at each point, by using 40 W of power with a high-frequency monopolar micro needle, regardless of the size of the ovary. The whole length of the needle (10 mm) was inserted into the ovary to ensure stromal damage.

Statistical analysis was done using Statistical Package for Social Sciences software (for Windows 17.0, SPSS Inc. Chicago, IL, USA). For comparison between parametric data, unpaired t-test was used to compare between two independent study groups. Comparisons of values before and after LOD in the PCOS group were done by using a paired t-test. For comparison of not normally distributed data, non parametric statistical tests (Mann-Whitney U-test and Wilcoxon signed ranks test) were used. A P value <.05 was considered statistically significant. The correlation between VEGF levels with other variables was evaluated by Spearman's rank correlation.

3. Results

Thirty CC-resistant women with PCOS undergoing LOD (PCOS group) and 30 fertile women with regular menstrual cycle and normal ovaries (control group) were recruited in this study. The baseline clinical characteristics, hormonal profile and 3D Doppler blood flow indices in the two groups are shown in Table 1. Acne and hirsutism were statistically more evident in the PCOS group. Before LOD, serum levels of VEGF, total T, FAI, LH, LH: FSH ratio, total AFC, total OV and the 3D power Doppler blood flow indices were significantly higher in the PCOS group.

After LOD, there was a significant reduction in the serum levels of VEGF, total T, SHBG, FAI, LH, LH:FSH ratio, total AFC, total OV and the 3D power Doppler blood flow indices and remained all low at 3- and 6-month follow-up (Table 2).

Table 1 Baseline clinical characteristics, hormonal profile and 3-D Doppler blood flow indices in the two groups.

Baseline patients characteristics PCOS group (n = 30) Control group (n = 30) p value

Age (years) 30.5 ± 1.4 30.6 ± 1.2 NS

Body mass index (kg/m2) 29.1 ± 1.2 28.9 ± 1.3 NS

Waist-hip ratio 0.87 ± 0.3 0.84 ± 0.4 NS

Acne 12 (40%) 1 (3.3%) <0.01

Hirsutism 8 (26.6%) 0 (0%) <0.05

Androgens:

T (nmol/l) 2.8 ± 0.2 1.21 ± 0.4 <0.001

DHEAS (ig/dl) 134.5 ± 12.2 131.1 ± 9.5 NS

SHBG (nmol/l) 42 ± 2.9 44 ± 1.7 NS

FAI 6.6 ± 1.2 2.75 ± 0.8 <0.001

LH (IU/l) 11.4 ± 1.4 4.6 ± 1.2 <0.001

FSH (IU/ml) 4.3 ± 1.2 3.9 ± 1.1 NS

LH/FSH ratio 2.65 ± 0.3 1.18 ± 0.2 <0.001

Serum VEGF (pg/ml) 669.4 ± 128.8 69.9 ± 24.4 <0.001

Antral follicular count 22 ± 2.5 13 ± 1.4 <0.001

Ovarian volume (cm3) 18.9 ± 1.7 7.5 ± 1.2 <0.001

Total ovarian VI 4.29 ± 1.8 2.2 ± 1.2 <0.05

Total ovarian FI 57.4 ± 4.6 40.2 ± 3.5 <0.001

Total ovarian VFI 2.1 ± 0.5 0.82 ± 0.3 <0.01

PCOS, poly cystic ovary syndrome; VEGF, vascular endothelial growth factor. Data are shown as mean ± SD.

Table 2 Pre LOD versus post LOD hormonal profile and 3D Doppler blood flow indices in the two groups.

Hormonal profile and 3-D Doppler blood flow indices Pre LOD 1-week 3-months 6-months

post LOD post LOD post LOD

Mean ± SD Mean ± SD p value* Mean ± SD p value** Mean ± SD p value***

Androgens:

T (nmol/l) 2.8 ± 0.2 1.5 ± 0.1 <0.001 1.56 ± 0.2 <0.001 1.58 ± 0.1 <0.001

DHEAS (ig/dl) 134.5 ± 12.2 132.5 ± 10.2 NS 134.1 ± 11.5 NS 135.2 ± 10.3 NS

SHBG (nmol/l) 42 ± 2.9 33.3 ± 3.1 <0.001 37.1 ± 2.6 <0.001 33.2 ± 4.5 <0.001

FAI 6.6 ± 1.2 4.5 ± 0.8 <0.001 4.2 ± 0.4 <0.001 2.5 ± 0.2 <0.001

LH (IU/l) 11.4 ± 1.4 7 ± 1.3 <0.001 6.18 ± 1.4 <0.001 6.14 ± 1.4 <0.001

FSH (Iu/ml) 4.3 ± 1.2 4.6 ± 2.3 NS 4.5 ± 2.1 NS 4.45 ± 2.4 NS

LH/FSH ratio 2.65 ± 0.3 1.52 ± 0.2 <0.001 1.37 ± 0.2 <0.001 1.38 ± 0.3 <0.001

VEGF (pg/ml) 669.4 ± 98.2 452 ± 95.3 <0.001 369.4 ± 88 <0.001 239.7 ± 92.2 <0.001

Total AFC 22 ± 2.5 16.75 ± 3.2 <0.001 15.2 ± 2.8 <0.001 14.5 ± 2.6 <0.001

Total OV (cm3) 18.9 ± 1.7 11.2 ± 1.6 <0.001 10.5 ± 1.8 <0.001 8.5 ± 2.1 <0.001

Total ovarian VI (%) 4.29 ± 1.8 2.3 ± 1.2 <0.001 2.25 ± 1.3 <0.001 2.28 ± 1.1 <0.001

Total ovarian FI 57.4 ± 4.6 45.8 ± 4.2 <0.001 46 ± 4.5 <0.001 44.3 ± 4.6 <0.001

Total ovarian VFI 2.1 ± 0.5 1.7 ± 0.4 <0.001 1.73 ± 0.3 <0.001 1.69 ± 0.6 <0.01

Data are shown as mean ± SD. * Pre LOD vs. 1-week post LOD. Pre LOD vs. 3-months post LOD. Pre LOD vs. 6-months post LOD.

There were significant positive correlations between power Doppler flow indices (VI, FI, and VFI) with serum VEGF, total T, and LH before and after LOD. No significant correlations were found between power Doppler flow indices and age, BMI, DHEAS, SHBG, FAI, FSH, LH/FSH ratio, total OV, or the total AFC (Table 3).

3.1. Reliability assessment

For intra-observer error, there was a good correlation of the consecutively repeated measurements for the right ovary (r = 0.871) and the left ovary (r = 0.873), and there was no significant difference between the two repeated measurement (P > 0.05). In addition because all the measurements were performed by the same operator in this study, there was no interobserver error in this study.

4. Discussion

Power Doppler ultrasound has been in clinical practice for several years. It has the advantage of being more sensitive to low flow, and thus overcomes the angle-dependence and aliasing of standard color Doppler. It displays the total flow in a confined area, giving an impression similar to that of angiography. This implementation of the 3D display permits the physician to see three dimensions on the screen interactively, rather than mentally assembling the sectional images. Thus, the 3D power Doppler system may enable physicians to study the region of interest in more detail (19).

The size and position of the ovaries make it an ideal organ for using transvaginal 3D power Doppler ultrasonography to quantify the Doppler signals within the entire ovary. We believe it is more accurate than the methods previously

Table 3 Correlation between 3D power Doppler indices and other study parameters in the PCOS group before and after LOD. Other study parameters Total ovarian VI Total ovarian FI Total ovarian VFI

Pre LOD Post LOD Pre LOD Post LOD Pre LOD Post LOD

r p value r p value r p value R p value r p value r p value

Age -0.104 0.756 -0.098 0.875 -0.084 0.915 -0.066 0.868 -0.115 0.679 -0.124 0.856

BMI -0.271 0.365 -0.202 0.465 -0.169 0.756 -0.112 0.664 -0.194 0.567 -0.148 0.657

Total T 0.745 0.001 0.668 0.001 0.641 0.001 0.682 0.001 0.563 0.001 0.621 0.001

DHEAS 0.114 0.891 0.054 0.786 0.051 0.985 0.016 0.768 0.088 0.690 0.064 0.848

SHBG 0.021 0.854 0.100 0.756 -0.022 0.689 -0.013 0.987 -0.005 0.765 0.011 0.816

FAI 0.326 0.113 0.311 0.203 0.256 0.412 0.306 0.208 0.226 0.531 0.235 0.542

LH 0.572 0.001 0.566 0.001 0.465 0.01 0.468 0.01 0.438 0.01 0.426 0.01

FSH 0.067 0.854 0.102 0.785 0.068 0.859 0.023 0.874 0.006 0.942 0.069 0.864

LH/FSH ratio 0.214 0.648 0.224 0.685 0.125 0.752 0.111 0.768 0.095 0.853 0.097 0.822

VEGF 0.694 0.001 0.684 0.001 0.662 0.001 0.611 0.001 0.614 0.001 0.589 0.001

Total AFC 0.421 0.124 0.387 0.167 0.368 0.223 0.334 0.225 0.189 0.457 0.219 0.462

Total OV 0.325 0.168 0.226 0.356 0.275 0.256 0.154 0.725 0.333 0.165 0.296 0.452

r, correlation coefficient; LOD, laparoscopic ovarian drilling; p, probability; BMI, body mass index.

reported used to measure blood flow changes in PCOS because the 3D power Doppler histogram analysis can quantify the whole ovarian stroma Doppler signal via a 3D reconstructive figure, which can really reflect the whole stroma flow data while 2D power Doppler cannot (19). Three-dimensional ultrasound is a more appropriate new tool to assess PCOS because it facilitates an objective measurement of follicle count, total ovarian and stromal echogenicity, OV and ovarian blood flow in a way that has not been possible before (20).

Ovarian blood flow has been shown by 2D ultrasound to increase in patients with PCOS (20). Studies using 3D sono-graphic techniques have reported conflicting results. Some studies reported an increased OV and vascularization in patients with PCOS (19,22). Other studies showed no differences in ovarian blood flow compared to healthy controls (21,23). These conflicting results may be explained by the fact that many of these studies have limited power because of small sample sizes and open inclusion/exclusion criteria that resulted in the recruitment of inappropriate controls. In addition, different criteria for the diagnosis of PCOS, variable Doppler settings and inconsistencies in the phase of cycle when the examinations were conducted.

In the present study, ovarian stromal blood flow was shown to be significantly higher in patients with PCOS than the control group. This was in agreement with previous studies (11,14,25,28). The increased vascularity in patients with PCOS may be due to over expression of ovarian VEGF secondary to higher serum LH levels in these women (11). The rise in VEGF may also explain the higher risk of OHSS in patients with PCOS (26) which is minimized by LOD as one of its advantages (27).

The present study has reported a significant reduction in the serum levels of VEGF, total T, SHBG, FAI, LH, LH: FSH ratio and the 3-D power Doppler indices after LOD. These results are in agreement with many previous reports (11,12,14,15,25). In contrast, Vizer and co-workers (13) reported an increased intra-ovarian blood flow after the procedure.

The mechanism of action of LOD is unclear and its beneficial effect is apparently due to the destruction of the androgen-producing ovarian stroma with subsequent decrease in ovarian stromal blood flow, decreased serum levels of VEGF and IGF-I which are significantly higher in PCOS (14,25).

The present study has reported a significantly higher AFC and total ovarian volume [OV] in patients with PCOS before LOD. After LOD, there was a significant reduction in AFC and total OV and remained low at 3 and 6 month intervals. These findings are in agreement with previous studies (5,14,29-31). The mechanism of reduction of OV after LOD is not clear. It may be explained by normalization of ovarian function after LOD (30). The reduction in the androgen level after LOD may partly play a role in lowering AFC (32,33).

The present study has reported significant positive correlations between power Doppler blood flow indices with serum VEGF, total T, and LH before and after LOD. This was in agreement with previous studies (11,14,15,24,25). These findings may be attributed to tonic secretion of LH in early follic-ular phase in PCOS which is associated with theca and stromal cell hyperplasia and consequent androgen production. Moreover, stromal vascularity is significantly higher in women with PCOS who are hyperandrogenic and lean rather than nor-moandrogenic and obese (33). Also, these findings may be explained by a mechanism of neovascularization or activation of vasoactive factors that in turn may influence the androgen

synthesis within the ovary (28). This mechanism suggests that PCOS represents the end of a spectrum that includes ovarian stromal hypertrophy, increased stromal blood flow, and androgen overproduction.

It may be postulated that the use of 3D power Doppler sonography facilitates objective assessment of the whole ovarian stromal vascularization, whereas 2D color and power Doppler techniques provide information about a specific area of the ovary. However, 3D power Doppler ultrasound has limitation in terms of computer algorithms, mathematical and biophysical limitations associated with the flow indices, the need for standardized Doppler settings, and the lack of uniformity in previous studies. This may explain possible delay in the clinical use of 3D Doppler imaging as a new sonographic marker for the diagnosis of PCOS.

One shortcoming of the present study is its small sample size, which makes it underpowered; another is that the risk of damaging ovarian reserve by LOD should have been more fully assessed by a longer follow-up of FSH in the PCOS group. In conclusion, serum VEGF and ovarian blood flow indices were higher in women with PCOS than in normal women. LOD reduced serum levels of VEGF, in addition to ovarian blood flow indices, in women with PCOS. 3D power Doppler ultrasound may provide substantial assistance to the management of the PCOS and is worthy of further research. A large prospective multicenter study is recommended to study more the correlation between LOD, ovarian stromal blood flow, and ovarian steroidogenesis.

Conflict of interest

We have no conflict of interest to declare. References

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