Table 2. Magnetic resonance imaging findings of internal mammary lymph nodes.
| Variable | Benign (n = 19) No. (%) |
Malignant (n = 40) No. (%) |
p-value |
|---|---|---|---|
| Short axis length (mm)* | 3.6 ± 1.3 | 8.2 ± 2.9 | 0.000 |
| Long axis length (mm)* | 8.1 ± 2.4 | 14.5 ± 4.8 | 0.000 |
| S/L ratio* | 0.45 ± 0.10 | 0.59 ± 0.17 | 0.041 |
| Fatty hilum | 0.000 | ||
| Absence | 0 | 38 (95.0) | |
| Presence | 19 (100.0) | 2 (5.0) | |
| Multiplicity | 0.795 | ||
| Single | 13 (68.4) | 26 (65.0) | |
| Multiplicity | 6 (31.6) | 14 (35.0) | |
| Intercostal space | 0.907 | ||
| 1st | 1 (5.3) | 10 (25.0) | |
| 2nd | 16 (84.2) | 17 (42.5) | |
| 3rd | 1 (5.3) | 12 (30.0) | |
| 4th | 1 (5.3) | 1 (2.5) | |
| DWI signal intensity | 0.000 | ||
| Hyperintense | 8 (42.1) | 35 (87.5) | |
| Isointense | 7 (36.8) | 4 (10.0) | |
| Hypointense | 1 (5.3) | 0 | |
| Unknown† | 3 (15.8) | 1 (2.5) | |
| ADC map‡ | 0.000 | ||
| Decreased | 3 (15.8) | 34 (85.0) | |
| Isointense | 12 (63.2) | 4 (10.0) | |
| Increased | 1 (5.3) | 0 | |
| Unknown† | 3 (15.8) | 2 (5.0) |
S/L ratio=short axis length/long axis length ratio; DWI=diffusion weighted imaging; ADC=apparent diffusion coefficient.
*Mean±SD; †Signal intensity on DWI and ADC map could not be evaluated due to poor image quality; ‡Signal intensity on ADC map in comparison with DWI.