TABLE 2.
Likelihood of Malignancy for MRI BI-RADS Category 4 Lesions
| BI-RADS Category | No. of Examinations | No. of Malignancies | PPV2 (%) | 95% CI | Likelihood Range for Mammography and Ultrasound (%)a |
|---|---|---|---|---|---|
|
| |||||
| 4A | 40 | 1 | 2.5b | 0.0–14.7 | > 2 to ≤ 10 |
| 4B | 29 | 8 | 27.6b | 13.4–47.5 | > 10 to ≤ 50 |
| 4C | 6 | 5 | 83.3b | 36.5–99.1 | > 50 to < 95 |
| 4 (NOS) | 7 | 2 | 28.6 | 5.1–69.7 | |
| 5 | 2 | 2 | 100.0 | 19.8–100 | ≥ 95 |
|
| |||||
| Total | 84 | 18 | 21.4 | 13.5–32.0 | |
Note—PPV2 = positive predictive value level 2 (based on recommendation for tissue diagnosis), NOS = not otherwise specified.
a
Benchmark ranges for likelihood of malignancy for mammography and ultrasound in accordance with American College of Radiology BI-RADS fifth edition [1].
b
PPV2 values for all three categories are statistically significantly different (p < 0.05) from one another.