Table 3. Frequency and Malignant Risk of Suspicious Ultrasonography (US) Features According to Solidity, Echogenicity, and Combination of Solidity and Echogenicity.
| Group | Microcalcifications (n = 189) | Non-Parallel Orientation (n = 216) | Spiculated/Microlobulated Margin (n = 161) | Any Three Suspicious US Features (n = 368) | None of Three Suspicious US Features (n = 534) | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| Malignancy Risk (%) | Frequency (%) | Malignancy Risk (%) | Frequency (%) | Malignancy Risk (%) | Frequency (%) | Malignancy Risk (%) | Frequency (%) | Malignancy Risk (%) | Frequency (%) | |
| All (n = 902) | 61.4 (116/189) | 21.0 (189/902) | 65.3 (141/216) | 23.9 (216/902) | 83.2 (134/161) | 17.8 (161/902) | 60.3 (222/368) | 40.8 (368/902) | 8.2 (44/534) | 59.2 (534/902) |
| Solidity | ||||||||||
| Solid (n = 715) | 64.5 (111/172) | 24.1 (172/715) | 70.4 (138/196) | 27.4 (196/715) | 84.0 (131/156) | 21.8 (156/715) | 65.3 (216/331) | 46.3 (331/715) | 9.6 (37/384) | 53.7 (384/715) |
| Partially cystic (n = 179) | 31.3 (5/16) | 8.9 (16/179) | 15.0 (3/20) | 11.2 (20/179) | 60.0 (3/5) | 2.8 (5/179) | 16.7 (6/36) | 20.1 (36/179) | 4.9 (7/143) | 79.9 (143/179) |
| Echogenicity | ||||||||||
| Hypoechoic (n = 474) | 74.0 (111/150) | 31.6 (150/474) | 75.5 (139/184) | 38.8 (184/474) | 83.3 (130/156) | 32.9 (156/474) | 71.9 (215/299) | 63.1 (299/474) | 20.0 (35/175) | 36.9 (175/474) |
| Isohyperechoic (n = 428) | 12.8 (5/39) | 9.1 (39/428) | 6.3 (2/32) | 7.5 (32/428) | 80.0 (4/5) | 1.2 (5/428) | 10.1 (7/69) | 16.1 (69/428) | 2.5 (9/359) | 83.9 (359/428) |
| Combination | ||||||||||
| Solid hypoechoic (n = 436) | 74.1 (106/143) | 32.8 (143/436) | 77.0 (137/178) | 40.8 (178/436) | 84.1 (127/151) | 34.6 (151/436) | 73.4 (210/286) | 65.6 (286/436) | 21.3 (32/150) | 34.4 (15/436) |
| Solid isohyperechoic (n = 279) | 17.2 (5/29) | 10.4 (29/279) | 5.6 (1/18) | 6.5 (18/279) | 80.0 (4/5) | 1.8 (5/279) | 13.3 (6/45) | 16.1 (45/279) | 2.1 (5/234) | 83.9 (234/279) |
| Partially cystic hypoechoic (n = 38) | 71.4 (5/7) | 18.4 (7/38) | 33.3 (2/6) | 15.8 (6/38) | 60.0 (3/5) | 13.2 (5/38) | 38.5 (5/13) | 34.2 (13/38) | 12.0 (3/25) | 65.8 (25/38) |
| Partially cystic isohyperechoic (n = 141) | 0 (0/9) | 6.4 (9/141) | 7.1 (1/14) | 9.9 (14/141) | 0 (0/0) | 0 (0/141) | 4.3 (1/23) | 16.3 (23/141) | 3.4 (4/118) | 83.7 (118/141) |
| Partially cystic or isohyperechoic (n = 466) | 21.7 (10/46) | 9.9 (46/466) | 10.5 (4/38) | 8.2 (38/466) | 70.0 (7/10) | 2.1 (10/466) | 14.6 (12/82) | 17.6 (82/466) | 3.1 (12/384) | 82.4 (384/466) |