Table 2. MRI BI-RADS Assessments and Recommendations and Post-MRI Biopsies Performed .
| Variable | No. (%) of Patients |
|---|---|
| Pure DCIS Preoperative MRI Final Surgery Known (n = 339) | |
| MRI BI-RADS assessment category | |
| 0 | 12 (3.5) |
| 1 or 2 | 6 (1.8) |
| 3 | 1 (0.3) |
| 4 or 5 | 63 (18.6) |
| 6 | 254 (74.9) |
| Not reported or unknown | 3 (0.9) |
| MRI BI-RADS recommendation | |
| Surgical excision or routine follow-up | 222 (65.5) |
| Tissue diagnosis | 77 (22.7) |
| Targeted ultrasonography | 27 (8.0) |
| Short-interval (6-mo) follow-up | 7 (2.1) |
| Not reported or unknown | 6 (1.8) |
| Additional Biopsy Performed After MRI (n = 66) | |
| No. of lesions biopsied | |
| 1 | 48 (72.7) |
| 2 | 16 (24.2) |
| 3 | 2 (3.0) |
| Biopsy side | |
| Ipsilateral | 39 (59.1) |
| Contralateral | 16 (24.2) |
| Both | 11 (16.7) |
| Post-MRI biopsy guidancea | |
| MRI | 37 (56.1) |
| Ultrasonography | 21 (31.8) |
| Mammography | 8 (12.1) |
| Most severe histologic findingsb | |
| Benign | 28 (42.4) |
| High risk | 17 (25.8) |
| Malignant | 21 (31.8) |
| DCIS | 15 (22.7) |
| Invasive | 6 (9.1) |
Abbreviations: BI-RADS, Breast Imaging Reporting and Data System; DCIS, ductal carcinoma in situ; MRI, magnetic resonance imaging.
a
For instances of multiple lesions biopsied, guidance is reported at the patient level using the following highest-order ranking: MRI greater than ultrasonography greater than mammography.
b
For instances of multiple lesions biopsied, histologic findings are reported at the patient level using the following highest-order ranking: invasive greater than DCIS greater than high risk greater than benign.