Research ArticleOriginal Article
Open Access

Accuracy of imaging of BI-RADS 4 subcategorizations in breast lesion diagnosis

Radiologic-pathologic correlation

Hadeel A. Ghunaim, Rana E. Alatawi, Walaa M. Borhan, Tareef S. Daqqaq, Ayman S. Alhasan, Mervat M. Aboualkheir and Reem M. Elkady
Saudi Medical Journal November 2024, 45 (11) 1228-1237; DOI: https://doi.org/10.15537/smj.2024.45.11.20240001

Article Figures & Data

Figures

  • Figure 1
    Figure 1

    - Pathological distribution of benign lesions found (n=206). UDH: usual ductal hyperplasia, ADH: atypical ductal hyperplasia

  • Figure 2
    Figure 2

    - Pathological distribution of malignant lesions found (n=41). IDC: invasive ductal carcinoma, ILC: invasive lobular carcinoma

  • Appendix 1
    Appendix 1

    - Data handling, imaging, and biopsy of the raters.

  • Appendix 2
    Appendix 2

    - Mammography and sonography of a 65-year-old woman presented with clear right nipple discharge. A) Standard craniocaudal and B) mediolateral oblique views were obtained. Focal asymmetry in the right inner lower anterior to middle third (arrows) was detected. C-D) Sonography. It showed an avascular branching mass with posterior acoustic enhancement measuring 2x1.7x3 cm at 4 O’clock. Bilateral Abnormal axillary lymph nodes with cortical thickening approximately 0.4 cm. The histology of US-guided biopsy revealed intraductal papilloma.

  • Appendix 3
    Appendix 3

    - Mammography and sonography of 43-year-old women. A) Standard craniocaudal and B) mediolateral oblique views were obtained. Focal asymmetry was detected in the upper outer quadrant left breast (arrows). C) Sonography. It showed a heterogenous mass with an indistinct border measuring 7mm at 2 O’clock (arrow). The histology of the US-guided biopsy revealed benign breast tissue.

Tables

  • Table 1

    - Baseline characteristics of the studied sample (N=247).

    Variablesn (%)
    Age (years), mean±SD44.47±14.35
    Age (years), median (IQR)44.5 (35.0-54.0)
    Ultrasound
    Yes246 (99.6)
    No1 (0.4)
    Mammography
    Yes197 (79.8)
    No50 (20.2)
    Affected side
    Left127 (51.4)
    Right120 (48.6)
    Lesion size (cm), mean±SD2.25±1.80
    Lesion size (cm), median (IQR)1.5 (1.0-2.8)
    Pathology
    Benign199 (80.6)
    Malignant41 (16.6)
    Hyperplasia7 (2.8)
    Imaging findings
    Mass164 (66.4)
    Mass with calcification14 (5.7)
    Calcification only5 (2.0)
    Asymmetry39 (15.8)
    Architectural distortion26 (10.5)
    Intraductal mass37 (15.0)
    Complex mass18 (7.3)
    Skin thickening6 (2.4)
    Nipple retraction2 (0.8)
    Mammography breast density (n=197)
    A28 (14.4)
    B84 (43.0)
    C75 (38.5)
    D8 (4.1)
    Lesion location
    Retroareolar57 (23.1)
    Upper outer quadrant133 (53.8)
    Lower outer quadrant22 (8.9)
    Upper inner quadrant20 (8.1)
    Lower inner quadrant15 (6.1)

    Values are presented as numbers and percentages (%), or mean ± standard deviation (SD), or median interquartile range (IQR).

    • Table 2

      - Validity of Rater 1 and Rater 2 decision according to pathology of the lesion.

      BIRADSPathologyP-value*
      BenignMalignant
      Rater 1
      4A (n=135)133 (98.5)2 (1.5)<0.001
      4B (n=68)63 (92.6)5 (7.4)
      4C (n=44)10 (22.7)34 (77.3)
      Rater 2
      4A (n=151)149 (98.7)2 (1.3)<0.001
      4B (n=48)44 (91.7)4 (8.3)
      4C (n=48)13 (27.1)35 (72.9)

      Values are presented as numbers and percentages (%).

      BIRADS: breast-imaging reporting and data system

      • ↵* Chi-square test for proportions was used to estimate the p-values.

    • Table 3

      - Comparison of positive predictive value of breast imaging-reporting and data system 4 subcategories with reference value.

      Rater BI-RADS subcategoryTotalBenignMalignantPPV for malignancyBIRADS PPV
      Actual (95% CI)Reference
      Rater 1
      4A135133 (98.5)2 (1.5)1.5 (0.2-5.2)>2 - ≤10
      4B6863 (92.6)5 (7.4)7.4 (2.4-16.3)>10 - ≤50
      4C4410 (22.7)34 (77.3)77.3 (62.2-88.5)>50 - <95
      Total247206 (83.4)41 (16.6) >2 - <95
      Rater 2
      4A151149 (98.7)2 (1.3)1.3 (0.2-4.7)>2 - ≤10
      4B4844 (91.7)4 (8.3)8.3 (2.3-20.0)>10 - ≤50
      4C4813 (27.1)35 (72.9)72.9 (58.2-84.7)>50 - <95
      Total247206 (83.4)41 (16.6) >2 - <95

      Values are presented as numbers and percentages (%).

      BI-RADS: breast-imaging reporting and data system, PPV: positive predictive value, CI: confidence interval

      • Table 4

        - Inter-rater agreement between the 2 raters of the lesions.

        Inter-raterRater 1K-values*
        Rater 2BIRADS
        Observer 24A4B4C
        BIRADS 4A121 (89.6)30 (44.1)0 (0.0)0.79 (0.73-0.85)
        BIRADS 4B12 (8.9)30 (44.1)6 (13.6) 
        BIRADS 4C2 (1.5)8 (11.8)38 (86.4)p<0.001
        Total1356844 

        Values are presented as numbers and percentages (%).

        BIRADS: breast-imaging reporting and data system

        • ↵* Weighted Cohen’s Kappa (K) value and 95% confidence interval (CI).

      • Table 5

        - Issues of differences in the feature assignment reported By Rater 1 and Rater 2.

        MammographyRater (n=52)P-values
        Rater 1Rater 2
        Density
        Hypo-1 (1.9)0 (0.0) 
        Iso-42 (77.8)31 (58.5)0.025*
        Hyper-11 (20.4)22 (41.5) 
        Shape (n=24)
        Oval7 (29.2)13 (54.2)0.041**
        Round11 (45.8)4 (16.7)0.044**
        Irregular6 (25.0)7 (29.1)0.124**
        Ultrasound (n=54)
        Echo
        Hypo-36 (66.7)43 (76.8) 
        Iso-1 (1.9)3 (7.1)0.264*
        Mixed17 (31.5)11 (16.1) 
        Vascularity (n=24)20 (83.3)3 (12.5)0.017**
        Borders (n=54)
        Circumscribed13 (24.1)24 (44.4)0.046**
        Indistinct13 (24.1)18 (33.3)0.102**
        Angular23 (42.6)1 (1.9)0.015***
        Micro-lobular29 (53.7)21 (38.9)0.048**
        Spiculated2 (3.7)1 (1.9)0.214***
        Anti-parallel7 (13.9)3 (5.6)0.084***

        Values are presented as numbers and percentages (%).

        • ↵* Monte Carlo exact test was used to compare the frequency differences between groups.

        • ↵** The Chi-square test was used to compare the frequency differences between groups.

        • ↵*** Fisher’s exact test was used to compare the frequency differences between groups.

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