The Evaluation of focal breast lesions using ultrasound elastography with FNAC and/or histopathology correlation among patients visiting breast ultrasound and mammography units at Tikur Anbessa Specialized Teaching Hospital, Ethiopia, August, 2025

Abstract

Background: Breast cancer continues to be a major cause of illness and death worldwide, including in Ethiopia. Traditionally, diagnosis in Ethiopia has relied on clinical palpation, mammography, and B-mode ultrasonography (US). Histopathological examination continues to be the gold standard for definitive diagnosis. Recently, elastography has emerged as a promising adjunct to B-mode ultrasonography, enhancing specificity and aiding in the early detection of breast cancer. Methodology: A prospective analytical cross-sectional study was carried out at Tikur Anbessa Specialized Hospital (TASH) between January 1 and April 30, 2025. Results: The study involved 100 patients, 72% had malignant breast lesions, 26% benign, and 2% atypical, with invasive carcinoma and fibroadenoma being the most common. BI-RADS alone showed high sensitivity (98.6%) but low specificity (10.7%). Adding elasticity scoring and strain ratio improved diagnostic accuracy. Elasticity scoring achieved 96% sensitivity and 68% specificity, while strain ratio had 97.2% sensitivity and 57.2% specificity. Serial testing method provided a more balanced approach with 91.3% sensitivity, 87.7% specificity, and 91% accuracy, reducing false positives while maintaining diagnostic strength. Conclusion: This study highlights the clinical value of integrating BI-RADS, elasticity scoring, and strain ratio in the ultrasound assessment of breast lesions. --------------------------------------------------- Introduction Breast cancer is the most common malignancy among women worldwide, with approximately 2.3 million new cases and 670,000 deaths reported in 2022(1). In Ethiopia, breast cancer is the leading cancer among women, accounting for about one-third of female cancers and one-fifth of all cancers overall. Despite this high burden, early and accurate diagnosis remains a major challenge (2). Traditionally, breast cancer diagnosis in Ethiopia has relied on clinical examination, mammography, and conventional B-mode ultrasonography, with histopathology as the diagnostic gold standard (3). Although ultrasound is widely used because of its availability, non-invasiveness, and real-time imaging capability, its relatively low specificity limits its ability to reliably distinguish benign from malignant lesions. This limitation is particularly evident in BI-RADS category 3 and 4A lesions, where malignancy risk is low but not negligible. As a result, many patients undergo frequent follow-up or unnecessary biopsies, which increase cost, patient anxiety, and healthcare burden. Poor patient adherence to imaging follow-up, largely due to financial limitations and inadequate awareness, often compels clinicians to opt for biopsy even in cases with a low likelihood of malignancy (4, 5). Ultrasound elastography, introduced as a technique to assess tissue stiffness, provides additional functional information that complements conventional ultrasound (6, 7). Both strain elastography and shear wave elastography have demonstrated improved specificity in differentiating benign from malignant breast lesions, particularly in equivocal cases (8, 9). Several international studies have shown that elastography, especially quantitative parameters such as strain ratio, can safely downgrade a significant proportion of BI-RADS 4A lesions, thereby reducing unnecessary biopsies without compromising cancer detection. Consequently, elastography has been incorporated into the ACR BI-RADS lexicon as an adjunct imaging tool (11, 12, 13). While extensive evidence from Asia, the Middle East, South America, and other regions supports the diagnostic value of elastography, data from sub-Saharan Africa, including Ethiopia, are scarce. Differences in patient demographics, breast cancer biology, healthcare access, and imaging practice patterns limit the direct applicability of foreign data to the Ethiopian population (14 -28). Therefore, there is a critical need to evaluate the role of ultrasound elastography in the characterization of breast lesions in Ethiopia. Generating local evidence on its diagnostic performance, particularly for BI-RADS 3 and 4A lesions, may help optimize patient management, reduce unnecessary biopsies, and improve cost-effective breast cancer care in resource-limited setting. Objective General Objective: To evaluate focal breast and post-mastectomy chest wall lesions using ultrasound elastography and correlate findings with FNAC/CNB results at TASH. Specific Objective: To determine the diagnostic performance (sensitivity, specificity, PPV, NPV, and accuracy) of ultrasound elastography in differentiating benign from malignant lesions. Materials and Methods The study was conducted at Tikur Anbessa Specialized Hospital (TASH) in Addis Ababa, the main teaching hospital of the School of Medicine at Addis Ababa University, which provides a wide range of clinical services. This single-center prospective analytical cross-sectional study was carried out from December 1, 2024 to April 30, 2025, to evaluate focal breast and post-mastectomy chest wall lesions using ultrasound elastography with correlation to FNAC/CNB findings. The source population included all patients attending the Breast and Mammography Unit of the Radiology Department, while the study population consisted of eligible patients who met the predefined inclusion and exclusion criteria. The study included females aged 16 to 80 years who had sonographically visible solid breast lesions smaller than 3 cm and categorized as BI-RADS 3, 4, or 5 on conventional ultrasound. For BIRADS 3 lesions, only those that had undergone fine needle aspiration cytology (FNAC) or biopsy were considered. Exclusion criteria were cystic lesions, solid lesions classified as BIRADS 2, lesions larger than 3 cm, lesions situated close to the skin surface or chest wall, and lesions without cytological or histopathological confirmation. The sample size was calculated to be 138 based on a proportion estimate of p=0.9. After accounting for a 5% non-response rate, the final adjusted sample size was 145. A biopsy enriched convenience sampling technique was employed. A pre-prepared data collection checklist adapted from ACR BIRADS guideline was used as the primary tool for data collection. The imaging equipment we used was the Mindray DC-60 Exp system, using the L14-6NE high-frequency linear array transducer. Data collection tool and procedure Lesions were initially evaluated using conventional B-mode ultrasonography, following a radial scanning pattern with patients in the supine position. Each lesion was classified into an appropriate BIRADS category based on conventional ultrasound features. Elastography Technique and Parameters Strain elastography data were obtained by positioning the field-of-view box to encompass the area from the subcutaneous fat layer down to the pectoralis muscle, while carefully avoiding the rib cage. Proper compression was verified by the appearance of two to three green blocks on the vertical column display on the left side of the ultrasound monitor; one or no block indicated insufficient compression, while four to five blocks signaled excessive pressure. Elasticity scores (ES) were assigned according to the 5-point Tsukuba classification system introduced by Itoh et al (31). Lesions scoring 1 to 3 were classified as benign, while scores of 4 or 5 were considered suspicious for malignancy. The strain ratio (SR) was calculated by positioning the first region of interest (ROI) within the lesion and the second ROI in adjacent subcutaneous fat at a similar size and depth. This measurement was repeated three times, and the average value was used to provide a quantitative evaluation of tissue stiffness. Histopathology The lesions underwent fine-needle aspiration cytology (FNAC), ultrasound-guided core biopsy, or surgical excision, with histopathological findings serving as the reference standard for evaluating the results of conventional ultrasound and elastography. Data Quality Control and Statistical Analysis Radiological image acquisition and evaluation were performed by a single radiologist trained in breast strain elastography. To ensure quality control, the operator received prior training in strain elastography techniques and adhered strictly to the standardized data collection procedures described above. The primary investigator checked the data for accuracy and consistency to ensure its completeness and quality, and then entered it into IBM SPSS version 25.0 for analysis. Nominal variables were summarized using frequencies and percentages. The associations between BI-RADS score, elasticity score, and strain ratio with biopsy results were analyzed, and a p-value of <0.05 was considered statistically significant. Receiver operating characteristic (ROC) curves were generated to evaluate the diagnostic performance of the methods by calculating the area under the curve (AUC). Comparisons between AUC values were performed descriptively, and no formal statistical test for differences between AUCs was applied. Correlations among the different diagnostic modalities were also assessed. The results were presented using tables and charts. Operational Definitions BIRADS score (BS)- Negative or Benign lesions:1 to 3, positive or Suspicious lesions: 4 and 5 (ACR BI-RADS Atlas, 5th Edition, Breast Imaging Reporting and Data System) Elasticity Score (ES)- Negative or Benign lesions: ES 1 to 3, Positive or Suspicious lesions: ES 4 and 5 (Itoh A et al. Breast disease: clinical application of US elastography) Strain Ratio (SR) - Negative or Benign lesions: SR < 3.1, Positive or Suspicious lesions: SR ≥ 3.1 (Zhi et al ultrasonic in breast cancer diagnosis) Parallel testing method:A lesion is classified as positive or suspicious if any one of the following parameters is positive or suspicious: BI-RADS score, elasticity score, or strain ratio. Serial testing method:A lesion is classified as positive or suspicious only when all three para