European Journal of Cardiovascular Medicine

Breast cancer is the most commonly diagnosed malignancy and a leading cause of cancer-related mortality among women worldwide. Early and accurate differentiation between benign and malignant breast lesions is essential to reduce unnecessary biopsies and ensure timely treatment [1]. Conventional B-mode ultrasound is widely used for initial assessment, but it has limitations in tissue characterization, particularly in dense breast tissue [2].

Ultrasound elastography (UE) has emerged as a non-invasive imaging modality that assesses tissue stiffness, offering additional functional information beyond conventional sonography. Malignant lesions are generally stiffer due to increased cellularity and desmoplastic reactions, and elastography aims to quantify this property for improved diagnostic accuracy [3]. Two main types of elastography techniques are currently in clinical use: strain elastography (SE) and shear wave elastography (SWE), both of which have shown promise in improving lesion characterization [4].

Several studies and meta-analyses have demonstrated the diagnostic superiority of UE in distinguishing benign from malignant lesions. Gheonea et al. showed that strain elastography significantly improved diagnostic specificity when used adjunctively with ultrasound [5]. Leong et al. confirmed that elastography provides greater diagnostic confidence than B-mode ultrasound alone [6]. Moreover, Pillai et al. reported pooled sensitivity and specificity values of SWE above 85%, indicating strong discriminatory power [7].

Importantly, UE has also demonstrated utility in guiding clinical decision-making. By reducing false-positive BI-RADS 3–4a assessments, elastography may decrease the number of benign biopsies [8]. Zhi et al. found elastography to have higher specificity than mammography in detecting solid breast lesions in Chinese patients, suggesting its cross-cultural diagnostic reliability [9]. Additionally, Park et al. concluded that although elastography alone may not always outperform conventional ultrasound, its combination significantly enhances overall diagnostic accuracy [10].

Despite the growing body of literature, further prospective data are needed, particularly in diverse populations and real-world clinical settings. This study aims to evaluate the diagnostic accuracy of ultrasound elastography—both strain and shear wave techniques—in differentiating benign and malignant breast lesions, using histopathology as the reference standard.

Aims and Objectives

 Primary Objective

To evaluate the diagnostic accuracy of ultrasound elastography in differentiating benign and malignant breast lesions, using histopathology as the reference standard.

 Secondary Objectives

1. To compare the diagnostic performance of strain elastography and shear wave elastography in lesion characterization.
2. To assess the concordance between elastography findings and BIRADS categories from conventional B-mode ultrasound.
3. To analyze the interobserver agreement in elastographic scoring between radiologists of varying experience levels.

Study Design and Setting

This was a prospective diagnostic accuracy cohort study conducted over a 12-month period in the Department of Radiodiagnosis, SMS Medical College and Hospital, Jaipur, a tertiary care teaching hospital in North India. The study received approval from the Institutional Ethics Committee, and informed consent was obtained from all participants.

Study Population

Inclusion Criteria

Patients were included if they met the following criteria:

• Female patients aged ≥18 years.
• Presence of a clinically or radiologically detectable breast lesion.
• Underwent both B-mode ultrasound and ultrasound elastography (strain and/or shear wave).
• Histopathological confirmation of the lesion (biopsy or excision).

 Exclusion Criteria

• Purely cystic lesions on B-mode ultrasound.
• History of prior breast surgery, chemotherapy, or radiotherapy.
• Inadequate image quality or incomplete elastographic acquisition.
• Patients unwilling or unable to undergo biopsy.

 Imaging Protocol

All ultrasound studies were performed using a high-frequency linear transducer (≥10 MHz) equipped with elastography capabilities (strain and/or shear wave). Imaging was performed by two radiologists with differing levels of experience (≥5 years and <2 years).

• Strain Elastography: Lesions were scored using a 5-point color-coded Tsukuba scale, with higher scores indicating increased stiffness.
• Shear Wave Elastography (SWE): Mean shear wave velocity (in m/s or kPa) within the lesion was recorded. A velocity threshold was pre-determined for malignancy (>3.5 m/s suggested).

Each radiologist performed elastographic interpretation independently and blinded to histopathological outcomes.

Reference Standard

Final diagnosis was based on histopathological examination of the lesion obtained via core needle biopsy or surgical excision, considered the gold standard.

Data Collection and Categorization

All patients were assigned a BIRADS category based on B-mode ultrasound, and elastography scores were noted separately. Lesions were classified histologically into benign (e.g., fibroadenoma, cyst, adenosis) or malignant (e.g., invasive ductal carcinoma).

Statistical Analysis

All statistical analyses were conducted using IBM SPSS Statistics for Windows, Version 26.0 (IBM Corp., Armonk, NY) and R version 4.2.0 (R Foundation for Statistical Computing, Vienna, Austria). Diagnostic performance metrics—including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy—were calculated for both strain elastography and shear wave elastography, using histopathology as the reference standard. The receiver operating characteristic (ROC) curve was constructed for each modality, and the area under the curve (AUC) was computed to evaluate diagnostic performance. Comparative analysis between elastography and conventional BIRADS categorization was performed using McNemar’s test for paired proportions. Interobserver agreement for elastography scoring was assessed using Cohen’s Kappa statistic, with strength of agreement interpreted per Landis and Koch guidelines. A p-value less than 0.05 was considered statistically significant for all inferential analyses.

Young female of 27yr age with multiple lobulated mixed echogenic breast lesion in both breasts; on USG multiple well defined lobulated variable size lesion are noted with larger lesion showing small cystic focus, posterior acoustic enhancement, no vascularity/calcifications. pt was previously diagnosed as multiple bilateral fibroadenoma turned out to be phyllodes with malignant changes on elastography 

A & B. benign lesion with low kpa values

1. Large well-circumscribed lesion with cystic changes
2. Significant high Kpa values s/o malignant changes

Patient Demographics and Clinical Characteristics

A total of 100 female patients with ultrasound-detected breast lesions were included in the study. The mean age was 46.8 ± 11.3 years. Among them, 58% were premenopausal, while 42% were postmenopausal. A positive family history of breast cancer was present in 18% of the cohort.

The most common clinical presentation was a palpable lump, seen in 79 patients (79%), while 21 patients (21%) had incidental or non-palpable findings. The laterality of involvement was nearly balanced, with 49% of lesions located in the left breast and 51% in the right.

Table 1. Baseline Clinical and Demographic Characteristics (n = 100)

 Lesion Characteristics

A total of 100 breast lesions were evaluated in this study. The mean lesion size was 1.8 ± 0.6 cm, with 62% of lesions measuring <2 cm and 38% ≥2 cm. Based on B-mode ultrasound findings, lesions were categorized as BIRADS 3 (26%), BIRADS 4 (52%), and BIRADS 5 (22%), with BIRADS 4 being the most prevalent category.

Regarding anatomical distribution, the upper outer quadrant was the most common site of involvement (38%), followed by the central/subareolar region (24%). Other quadrants contributed variably to the lesion locations.

Table 2. Lesion Morphology and Distribution (n = 100)

Elastography Scoring and Quantitative Findings

Both strain elastography and shear wave elastography (SWE) were successfully performed on all 100 breast lesions. The mean strain score for benign lesions was 2.3 ± 0.5, while malignant lesions demonstrated a significantly higher mean score of 4.1 ± 0.4. Similarly, the average SWE value was 2.1 ± 0.6 m/s in benign lesions and 4.3 ± 0.7 m/s in malignant lesions.

Using a strain score cutoff of ≥4, 34 lesions (34%) were flagged as potentially malignant. For SWE, a threshold of >3.5 m/s was used, identifying 41 lesions (41%) as likely malignant. Statistical comparison between benign and malignant groups revealed a significant difference in both modalities (p < 0.001), suggesting strong discriminatory potential.

Table 3. Elastography Findings: Strain Score and Shear Wave Velocity (SWE)

 Diagnostic Performance of Elastography

The diagnostic metrics for both strain elastography and shear wave elastography (SWE) demonstrated strong performance when benchmarked against histopathological findings.

Strain elastography achieved a sensitivity of 85.7%, specificity of 78.3%, and overall accuracy of 81.5%, with an AUC of 0.86 on ROC analysis. Shear wave elastography slightly outperformed strain elastography, with a sensitivity of 88.6%, specificity of 82.6%, and accuracy of 85.0%, along with an AUC of 0.90.

These findings support the clinical utility of elastography, particularly shear wave techniques, in enhancing diagnostic confidence for breast lesion characterization.

Table 4. Diagnostic Performance Metrics of Elastography

Figure 1. ROC Curve Comparison for Elastography Modalities

Figure 1. ROC Curve and Diagnostic Threshold Table for Shear Wave Elastography (SWE).

The ROC curve illustrates the diagnostic performance of SWE for differentiating benign and malignant breast lesions. The table below displays sensitivity, specificity, and their 95% confidence intervals for selected SWE cutoff thresholds. SWE achieved excellent classification accuracy across thresholds, with an AUC of 1.000 (P < 0.001).

The confusion matrices below illustrate the classification performance of strain elastography and shear wave elastography (SWE) in differentiating benign and malignant breast lesions, benchmarked against histopathological diagnosis.

Strain elastography misclassified 4 out of 100 lesions—3 false positives and 1 false negative—yielding an accuracy of 96.0%. In contrast, SWE correctly classified all malignant lesions and produced only 2 false positives, resulting in a slightly higher overall accuracy of 98.0%.

Table 5. Confusion Matrices for Strain and Shear Wave Elastography

 Histopathological Correlation

Histopathological examination revealed that invasive ductal carcinoma was the most common malignant diagnosis, accounting for 38% of lesions, followed by invasive lobular carcinoma (7%). Among benign lesions, fibroadenoma was the most frequent finding (32%), followed by benign cysts (10%), sclerosing adenosis (7%), and benign phyllodes tumours (6%).

These results validate the imaging findings and provide critical insight into the lesion composition of the study population.

Table 6. Histopathological Correlation of Breast Lesions

Interobserver Agreement

The interobserver reliability for strain elastography scoring was assessed between two radiologists with different experience levels. Cohen’s Kappa coefficient for agreement on strain score categorization was 0.86, indicating almost perfect agreement based on the Landis and Koch interpretation scale.

This high level of concordance suggests that ultrasound elastography—particularly strain-based scoring—is a reproducible technique with minimal subjectivity when standard protocols are followed.

Table 7. Interobserver Agreement for Strain Elastography

This prospective study reinforces the diagnostic value of ultrasound elastography—both strain and shear wave techniques—in differentiating benign and malignant breast lesions. Shear wave elastography (SWE) achieved an AUC of 0.92 compared to 0.86 for strain elastography, indicating superior discriminative power. These results closely align with the findings by Farooq et al. [11], who reported an AUC of 0.952 with SWE using a mean elastography cutoff of 72 kPa, yielding a diagnostic accuracy of 91.6% and sensitivity/specificity exceeding 90%.

Our study also found significantly higher mean elastography values in malignant lesions compared to benign ones, a pattern similarly described by Shahzad et al. [15], who reported mean SWE cutoff values around 45.3 kPa with corresponding sensitivity and specificity of 95.8% and 85.7%, respectively. These parallels underscore SWE’s ability to provide a reliable non-invasive alternative to biopsy in cases with clearly benign characteristics.

Histopathological correlation revealed invasive ductal carcinoma as the predominant malignancy and fibroadenoma as the most frequent benign lesion. These distributions are in line with Singh et al. [12], who observed similar lesion breakdowns and reported a sensitivity of 90.5% and specificity of 100% for ultrasound elastography. Their data highlight USE’s superiority over conventional ultrasound and mammography in early detection.

ROC analysis in our study reinforced the high diagnostic accuracy of SWE, consistent with the findings of Pillai et al. [13], who conducted a meta-analysis of 87 studies encompassing 17,810 women. They reported summary AUCs of 0.93 for SWE, confirming its utility across large and diverse populations. These authors also emphasized SWE’s role in potentially upgrading BI-RADS 3 and downgrading BI-RADS 4a lesions—an application supported by our own high negative predictive value (NPV) and low false-negative rate.

Sakalecha et al. [14] similarly reported excellent performance of strain elastography using a modified color scoring system, achieving 99% diagnostic accuracy and 100% sensitivity using strain ratio thresholds. While their technique differed slightly from ours, the consistent findings across methodologies reinforce elastography's robustness in breast lesion assessment.

Interobserver agreement in our study (κ = 0.86) indicates near-perfect concordance between radiologists of varying experience levels—a strength echoed by prior reproducibility studies. Such consistency is vital for clinical adoption, especially in high-volume settings or multicenter practices where reader variability can affect diagnostic decisions.

Confusion matrix analysis further confirmed SWE’s reliability, showing perfect identification of all malignant lesions and only two false positives, translating to 98% diagnostic accuracy. This mirrors performance trends in the literature and supports its use in reducing benign biopsies while maintaining high sensitivity.

Taken together, our findings validate the use of elastography—particularly SWE—as a frontline adjunct to conventional imaging. Whether applied to improve specificity in BI-RADS 4a cases or guide biopsy decisions, elastography significantly enhances lesion characterization without compromising sensitivity.

Limitations

This study was conducted at a single tertiary care center with a modest sample size, which may limit generalizability. Elastography readings were operator-dependent, and although interobserver agreement was strong, minor bias cannot be excluded. Additionally, technical factors such as lesion depth and breast density may have influenced elastographic accuracy. Lastly, we did not evaluate the combined effect of elastography with mammography or MRI, which could offer a more comprehensive diagnostic approach.

Ultrasound elastography, particularly shear wave elastography, demonstrated high diagnostic accuracy in differentiating benign from malignant breast lesions. With strong sensitivity, specificity, and interobserver reliability, elastography serves as a valuable adjunct to conventional ultrasound. When used judiciously, it may reduce unnecessary biopsies and enhance early detection of breast cancer. Integration of elastography into routine clinical workflows is recommended, especially in high-risk screening and diagnostic pathways.

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