ORIGINALARTICLE

SIGNIFICANCE AND DIAGNOSTIC ACCURACY OF RESISTIVE INDEX IN PREDICTING

MALIGNANT OVARIAN MASSES KEEPING HISTOPATHOLOGY AS GOLD STANDARD

Sana Iqbal¹, Anam Safdar¹, Shandana Khan²

How to cite this article

ABSTRACT

OBJECTIVE

Iqbal S, Safdar A, Khan S.

This study aimed to determine the signicance and diagnostic accuracy of the

resistive index (RI) in predicting malignancy in ovarian masses, using

histopathology as the gold standard.

Signicance and Diagnostic Accuracy

of Resistive Index in Predicting

Malignant Ovarian Masses Keeping

Histopathology as Gold Standard. J

Gandhara Med Dent Sci.

2026;13(2):87-91

https://doi.org/10.37762/jgmds.13-2.813

METHODOLOGY

This prospective study was conducted at the Department of Radiology,

Northwest General Hospital and Research Centre, Peshawar, from Jan 1

2024, to Jul 31 2025. A sample size of 159 was calculated using the WHO

calculator. Patients were selected through convenience sampling. Trans-

abdominal Doppler Ultrasound was performed using a 3.5 MHz transducer

on a GE Logic 5 Doppler Ultrasound machine. The Resistive Index (RI) was

calculated for each case, and a threshold of 0.6 was used to dierentiate

benign from malignant lesions. Data analysis was done using SPSS version

25.

Date of Submission: 25-10-2025

Date Revised:

Date Acceptance:

19-02-2026

08-03-2026

²Assistant Professor, HOD, Department

of Radiology, Northwest General

Hospital and Research Centre, Peshawar

RESULTS

The sensitivity of the resistive index in predicting malignancy in ovarian

masses was 75.2%, and the specicity was 63.2%. The positive predictive

value of the RI was 86.7%, and the negative predictive value was 44.4% when

histopathology served as the gold standard. The mean age of patients in our

study was 48.3 ± 8.1 years.

Correspondence

¹Anam Safdar, Assistant Professor,

Department of Radiology, Northwest

General Hospital and Research Centre,

Peshawar

CONCLUSION

Doppler ultrasound and the resistive index are pivotal non-invasive tools for

predicting malignant risk in ovarian masses, with high diagnostic accuracy.

It has not only dramatically improved our ability to dierentiate benign from

malignant adnexal masses but also helped surgeons with preoperative

planning. Eect modiers like patient body habits and the performing

sonologist’s expertise. should be included in further studies to determine their

eect on the diagnostic accuracy of RI.

+92-332-9840175

anamsafdar33@gmail.com

KEYWORDS: Doppler Ultrasound, Resistive Index, Histopathology, Ovarian

Carcinoma

INTRODUCTION

diagnosis at an advanced stage largely drives the high

mortality rate of this disease.³The overall survival rate

Ovarian cancer is the fth most common cause of

cancer death among women and the second most

common gynecological malignancy.¹The incidence of

ovarian cancer has been rising signicantly among

younger women, likely due to the growing prevalence

of obesity, metabolic syndrome, increased estrogen

exposure, and lower birth rates.²The global incidence

and mortality rates of ovarian cancer for 185 countries

in 2020 were retrieved from the Global Cancer

Observatory (GLOBOCAN) database. In 2020, a total

of 313,959 new cases of ovarian cancer were recorded

globally, with an ASR (age-standardized rate) incidence

of 6.6 per 100,000. In 2020, a total of 207,252 new

deaths due to ovarian cancer were reported globally,

with an ASR mortality of 4.2 per 100,000.²Ovarian

cancer has the highest mortality rate of all gynecologic

cancers. The delayed onset of clinical symptoms and

for this disease is below 50%, but it can reach up to

90% when detected at stage I. Unfortunately, only

about 15% of cases are diagnosed this early. In contrast,

more than 60% of cases are identied at advanced

stages (III and IV), where the 5-year survival rate falls

to just 28%.⁴For ovarian cancer, screening tests tend to

have low specicity, leading to numerous false

positives and potentially unnecessary surgical or

therapeutic interventions. At the same time, low

sensitivity means that many cancers may go undetected.

As a result, true screening for ovarian cancer is not

currently feasible.⁴The best alternative is achieving an

accurate diagnosis at an early stage. For patients at high

risk of ovarian cancer, the most employed screening

method is yearly testing for serum CA125 and

transvaginal ultrasound (TVS). A major problem with

CA125 is its lack of specicity: it may be elevated in

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J Gandhara Med Dent Sci

Signicance and Diagnostic Accuracy of Resistive Index

Centre, Peshawar, from Jan 1 2024, to 31st july 2025.

other cancers, such as lung or pancreas, as well as many

benign conditions such as pelvic inammatory disease

and inammatory bowel disease etc.⁵Using CA125

levels to triage patients before proceeding to

transvaginal sonography (TVS), rather than performing

both tests simultaneously, results in better outcomes

with fewer false positives. Ultrasound is the primary

choice for evaluating pelvic masses due to its easy

availability, cost-eectiveness, and lack of ionizing

radiation.^3,5The International Ovarian Tumor Analysis

(IOTA) classies a tumor as benign, malignant, or

indeterminate.⁶This classication consists of two sets

of descriptors: Benign (B) features: unilocular cyst,

smooth multilocular tumor, solid component <7 mm in

Ethical approval for this study was obtained from the

Ethical Committee of Northwest General Hospital prior

to the commencement of data collection on 01-01-2024

(IRB 0239). Written informed consent was obtained

from all patients before their inclusion in the study.

Participants were informed about the purpose,

procedures, potential benets, and risks of the study, as

well as their right to withdraw at any time without

affecting their medical care. Participants' condentiality

and privacy were strictly maintained throughout the

study. Personal identiers were removed, and all data

were coded and analyzed anonymously. In this study,

we included 159 patients using convenience sampling.

diameter, the presence of acoustic shadows and no Females with an age range of 18-64 years and having

detectable Doppler signal and Malignant (M) features: symptoms of pelvic pain, abdominal bloating, weight

irregular solid tumor, irregular multilocular mass

>10 cm in diameter, ≥4 papillary structures, ascites and

high Doppler signal. An adnexal mass is classied as

malignant if at least one M-feature and no B-features

are present, and vice versa. Color Doppler imaging

combined with pulsed Doppler spectral analysis

enhances the assessment of ovarian masses by

evaluating blood ow within tumor tissue. The

neovascularization in tumors typically lacks a muscular

layer and exhibits low impedance with high-velocity

flow, resulting in a low resistive index.⁷Therefore,

benign and malignant tumors can be dierentially

diagnosed by RI.⁸82.5 % of malignant tumors had RI

less than 0.6, in contrast to only 6.81 % of benign

tumors in a study conducted in India.⁹In another study,

4 (11%) benign tumors with vascularity had an RI of

<0.6, compared to 100% of malignant tumors with an

RI of <0.6.¹⁰According to a study, the sensitivity and

specificity of various cut-o values of RI were

calculated. A cut-o value of RI <0.6 had sensitivities

of 82.1%, specicities of 100%, and positive and

negative predictive values of 72.2%, respectively.¹⁰

These ndings suggest a notable dierence in the

distribution of Resistive Index values between benign

and malignant neovascular ovarian tumors.⁷This study

aims to highlight the diagnostic accuracy of color

Doppler resistive index in the detection of malignant

ovarian masses. The gold standard for the diagnosis of

ovarian malignancy is histopathology. We stress again

that ultrasound‘s importance is to provide the

gynecologist with a simple tool to triage patients with

an ovarian mass. This study aims to evaluate the

diagnostic accuracy of Doppler resistive index in

distinguishing malignant from benign ovarian masses,

with histopathology as the gold standard.

loss, and/or positive family history were included.

Females with an age of less than 18 years, cysts less

than 2.5cm, and with obvious benign lesions like corpus

luteal cysts, and incomplete imaging or clinical data

were excluded. The exclusion criteria were strictly

adhered to to control for confounders and prevent bias

in the study results. Informed written consent was taken

from the patients. Doppler abdominopelvic ultrasound

was performed by senior sonologists who were blinded

to the clinical and surgical outcomes. In cases of

ambiguity, another sonologist was consulted to provide

an additional opinion and resolve the discrepancy. After

assessing the morphology, color ow Doppler was

activated. Flow was considered present when it

appeared centrally, and absent when no signal was

detected or when blood ow was only peripheral. Once

a central vessel was identied by the color Doppler US,

the spectral Doppler parameter "resistive index (RI)"

was automatically calculated. The lowest RI was used

for analysis if more than one vessel was within the

lesion. A threshold resistive index of 0.6 was used to

dierentiate benign from malignant lesions. Masses

were characterized as probably benign or possibly

malignant based on their sonographic appearance. The

perioperative ndings and histopathology reports of the

patients were traced. The data was entered into a

devised form. Data analysis was done using SPSS

version 25.

RESULTS

The study was conducted on 159 women presenting

with clinical features suspicious of an ovarian mass.

The mean age of women was 48.3 + 8.1 years. Patients

were divided into three age groups (Table 1). The

majority of malignant adnexal masses were noted in old

METHODOLOGY

age.

High-resolution

Doppler

ultrasound

was

performed, and a cut-o of 0.6 was used to predict

malignancy in an ovarian lesion. RI <0.6 was labelled

as possibly malignant, R1>0.6 was labelled as probably

This prospective study was conducted in the Radiology

Department, Northwest General Hospital, and Research

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J Gandhara Med Dent Sci

Signicance and Diagnostic Accuracy of Resistive Index

benign (Table 2). The histopathology reports were

sensitivity and specicity and have limited ecacy in

detecting early-stage OC.¹¹Approximately 66% of

patients are diagnosed at advanced stages, "FIGO"

stage III or IV, which have a 5 -year survival rate of

41% and 20%, respectively. Conversely, the 5-year

survival rates for stages I and II are approximately 93%

and 74%, respectively. Therefore, early-stage detection

and treatment of OC are vital.^11,12Ultrasonography is

typically the rst-line imaging modality for assessing

adnexal masses because of its high sensitivity in

traced. Results are shown in Table 3. The sensitivity of

RI on Doppler was found to be 75.2% and, specifically,

63.2%. The positive predictive value of the RI on

Doppler was 86.7%, and the negative predictive value

was 44.4% (Table 4).

Table 1: Age-Wise Distribution of the Sample (n = 159)

Frequency

%age

Age

Groups

(years)

Up to 35.00

10.1

35.01 to 50.00

50.01 & above

48.4

41.5

detecting

and

conrming

ovarian

masses,

distinguishing them from uterine masses, and ruling out

other pathologies. The addition of color Doppler

imaging with pulsed Doppler spectral analysis further

enhances the characterization of ovarian masses by

evaluating blood ow within tumor tissue.⁴The

theoretical basis lies in the observation that newly

formed tumor vessels resulting from angiogenesis dier

from normal vessels in terms of cellular composition,

basement membrane structure, and permeability.

Consequently, these dierences lead to altered

hemodynamic properties within the vessels. Resistive

index is an ultrasound parameter used to assess vascular

system resistance. Calculated as RI = peak systole- end

diastole/peak systole, the RI evaluates arterial

waveforms in which the reverse ow component is

absent. The value may be determined from just two

well-dened spots in the spectral display, and it is not

sensitive to changes in beam or vessel angle.⁷Study

showed that a cut-o value of RI <0.6 had a sensitivity,

specificity, positive predictive value, and negative

predictive value of 82.1%, 100%, 100%, and 72.2%,

respectively.¹⁰In another study, the results showed that

using a cut-o resistance index value of 0.6, the

sensitivity and specicity of color Doppler in the

detection of malignant tumors were 82% and 72%,

respectively.¹³A notable dierence was found in the

Resistive Index values between benign and malignant

ovarian tumors. Among the benign tumors (n=12), none

had an RI <0.4. Three tumors (25.0%) fell within the RI

range of 0.4-0.6, and most benign tumors (9, 75.0%)

had an RI >0.6. A considerable proportion of malignant

tumors (35.0%) exhibited an RI <0.4, indicating a lower

resistance pattern.⁷Yet another study showed that

considering the RI value of 0.64 as the cut-o point, the

sensitivity and specicity were 95.1% and 90.3%,

respectively.¹⁴In our study, the sensitivity of RI on

Doppler was found to be 75.2% and the specicity

63.2%. The positive predictive value of the RI on

Doppler was 86.7%, and the negative predictive value

was 44.4%. These ndings highlight the importance of

using color Doppler imaging and hemodynamic

parameters to dierentiate between benign and

Table 2: Malignant Ovarian Mass on Doppler U/S Using RI

(n=159)

Frequency

%age

Ovarian mass

classification

using RI on

Doppler

Possibly

Malignant

Probably

benign

105

66.0

34.0

Table 3: Classication of Ovarian Mass on Histopathology

(n=159)

Frequency

121

%age

76.1

23.9

Ovarian mass on Malignant

histopathology

Benign

Table 4: RI On Doppler & Histopathology 2 X2 Table (n = 159)

Malignant Ovarian Mass on

Histopathology

Positive

Negative

Malignant

ovarian mass

on RI

Positive

Negative

91 (TP)

14 (FP)

30 (FN)

24 (TN)

Note: Sensitivity: TP/TP + FN = 75.2%, Specicity:

TN/TN + FP = 63.2%, Positive Predictive Value:

TP/TP + FP = 86.7%, Negative Predictive Value:

TN/TN + FN = 44.4%.

DISCUSSION

Ovarian cancer (OC) ranks as the seventh most

common cancer among women and remains the

deadliest gynecologic malignancy. It poses a major

global health concern, with over 324,000 new cases and

more than 200,000 deaths reported each year.¹¹OC is

characterized by late-stage diagnosis, a poor prognosis,

and 5-year survival rates ranging from 93% (early

stage) to 20% (advanced stage).¹¹Despite progress in

genomics and proteomics, eective early-stage

diagnostic tools and population-wide screening

strategies remain elusive, contributing to high mortality

rates. Current diagnostic modalities, including imaging

techniques (transvaginal ultrasound, computed/positron

emission tomography, and

magnetic resonance

malignant

ovarian

tumors.

The

detection

imaging) and biomarkers (CA-125 and human

epididymis protein 4) oer varying degrees of

neovascularity, together with spectral Doppler indices

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J Gandhara Med Dent Sci

Signicance and Diagnostic Accuracy of Resistive Index

2. Huang J, Chan WC, Ngai CH, Lok V, Zhang L, Lucero-Prisno

such as RI values, can help characterize and distinguish

these lesions. Although opinions vary regarding optimal

DE III, et al. Worldwide burden, risk factors, and temporal

trends of ovarian cancer: A global study. Cancers (Basel).

cut-o

values,

there

consensus

that

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neovascularization is

fundamental feature of

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malignant transformation, and recognizing it may allow

detection of the earliest stages of ovarian oncogenesis.

In the future, research should be directed at comparing

the new color e-flow abdominopelvic Doppler

ultrasound with other modalities, especially three-

dimensional color Doppler, for detecting ovarian

malignancy. Because of the low incidence of ovarian

cancer, one can initiate this ovarian malignancy

screening program in the high-risk population so that

the ecacy of this method can be evaluated. Advanced

imaging modalities, such as MRI, should be used when

US results are indeterminate or equivocal.¹⁵

2022;14(12):2885.

https://doi.org/10.3390/cancers14122885.

PMID: 35740455; PMCID: PMC9225201.

4. Abramowicz JS, Condous G, Timmerman D. Ovarian mass—

dierentiating benign from malignant: Why the International

Ovarian Tumour Analysis rules should be implemented in

Australasia. Australas J Ultrasound Med. 2018;21(3):121-125.

https://doi.org/10.1002/ajum.12092 PMID: 30459943; PMCID:

PMC6223954.

5. Yu Z, Sun Y. Evaluating pretreatment serum CA-125 levels as

prognostic biomarkers in endometrial cancer: A comprehensive

meta-analysis.

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Oncol.

2024;14:1442814.

https://doi.org/10.3389/fonc.2024.1442814.

6. Sujata P, Mishra SP, Kurra J, Kar D, Bhuyan R. Preoperative

risk assessment of adnexal masses using simple rules from the

International Ovarian Tumor Analysis group. Ann Rom Soc

Cell Biol. 2021;25(2):1340-1351.

CONCLUSIONS

Resistive index in abdominopelvic Doppler imaging is

the non-invasive modality of choice, with high

diagnostic accuracy in dierentiating benign and

malignant adnexal masses; however, it is not an

alternative to CT or MRI. It has signicantly enhanced

preoperative dierentiation and supports surgeons in

making informed clinical decisions. This review

underscores the urgent need for ongoing research and

innovation to improve early detection, reduce mortality,

and optimize patient outcomes in ovarian cancer.

Advancements in personalized medicine, the integration

of emerging technologies, and the development of

targeted global initiatives and collaborative eorts are

essential to address disparities in access to care and to

promote cost-eective, scalable screening strategies as

key approaches to combat ovarian cancer.

7. Dhir YR, Roy A, Maji S, Karim R. Sonological accuracy in

defining benign and malignant ovarian neoplasms with colour

Doppler and histopathological correlation. Int J Acad Med

Pharm. 2023;5(3):2308-2311.

8. Kodali S, Sundari LD, Shah D. Correlation of clinical, Doppler

study and histopathological features of ovarian tumors. J South

Asian

Feder

Obstet

Gynaecol.

2022;14:257-260.

https://doi.org/10.5005/jp-journals-10006-2057.

9. Shah D, Shah S, Parikh J, Bhatt CJ, Vaishnav K, Bala DV.

Doppler ultrasound: A reliable predictor of ovarian malignancy.

Obstet

Gynaecol

India.

2013;63(3):186-189.

https://doi.org/10.1007/s13224-012-0255-8 PMID: 24426372;

PMCID: PMC3893995.

10. Mahale N, Kumar N, Mahale A, Ullal S, Fernandes M, Prabhu

S. Validity of ultrasound with color Doppler to dierentiate

between benign and malignant ovarian tumours. Obstet Gynecol

Sci. 2024;67(2):227-234. https://doi.org/10.5468/ogs.23167

PMID: 38395074; PMCID: PMC10901352.

11. Hong MK, Ding DC. Early diagnosis of ovarian cancer:

Advances, challenges, and future directions. Diagnostics

(Basel).

2025;15(4):406.

https://doi.org/10.3390/diagnostics15040406.

LIMITATIONS

12. Torre LA, Trabert B, DeSantis CE, Miller KD, Samimi G,

Runowicz CD, et al. Ovarian cancer statistics, 2018. CA Cancer

J Clin. 2018;68(4):284-296. https://doi.org/10.3322/caac.21456

PMID: 29809280.

Conducting the study at a single center limits its

generalizability. Eect modiers such as patient body

habitus, the expertise of the performing sonologist, etc.,

should be included in future studies to determine their

effect on the diagnostic accuracy of RI.

13. Nighat S, Tariq A, Iqbal N, Nadeem J, Imran H, Ishaque S.

Accuracy of ultrasonography and color Doppler in the diagnosis

of ovarian masses and correlation with histopathology. Pak J

Med Dent. 2025;14(4).

14. Miao K, Zhao N, Lv Q, He X, Xu M, Dong X, et al. Prediction

of benign and malignant ovarian tumors using ResNet34 on

ultrasound images. J Obstet Gynaecol Res. 2023;49(12):2910-

2917. https://doi.org/10.1111/jog.15849PMID: 37754803.

15. Abd Elrahman EO, Hemida R, Ghanem AA, Shams-Eldin N,

Mohamed AA. Doppler ultrasound versus pelvic magnetic

resonance imaging in diagnosis of ovarian mass in teenagers: A

prospective study. Egypt J Hosp Med. 2023;92(1):5508-5518.

16. Sujana K, Pranathi L, Jyothi S. To evaluate the ecacy of

ultrasonography and colour Doppler in the diagnosis and

characterization of gynaecological pelvic masses. J Popul Ther

Clin Pharmacol. 2024.

CONFLICT OF INTEREST: None

FUNDING SOURCES: None

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AUTHORS CONTRIBUTION

in ovarian masses and correlation with CA-125. Eur

Cardiovasc Med. 2025;15(7).

Sana Iqbal - Concept & Design; Data Acquisition; Data

Analysis/Interpretation; Drafting Manuscript; Critical

Revision; Supervision; Final Approval

Anam Safdar - Concept & Design; Data Acquisition; Data

Analysis/Interpretation; Drafting Manuscript; Critical

Revision; Supervision; Final Approval

Shandana Khan - Concept & Design; Data Acquisition; Data

Analysis/Interpretation; Drafting Manuscript; Critical

Revision; Supervision; Final Approval

The authors accept responsibility for all aspects of the work

and will ensure that any concerns regarding the accuracy or

integrity of any part are properly investigated and resolved.

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