Comparison of structural changes observed on MRI with structural changes on conventional radiographs based on the modified New York criteria
| Structural changes on MRI | Radiographs of SI joint* | Total | |
|---|---|---|---|
| Abnormal | Normal | ||
| *Patients fulfilled the modified New York criteria on MRI if structural changes were present and on conventional radiography if there were bilateral changes of at least grade 2 or unilateral of at least grade 3. | |||
| MRI, magnetic resonance imaging; SI, sacroiliac. | |||
| (a) Single sacroiliac joint analysis | |||
| Present | 18 | 2 | 20 |
| Absent | 19 | 97 | 116 |
| Total | 37 | 99 | 136 |
| (b) Per patient analysis | |||
| Present in both SI joints | 8 | 0 | 8 |
| Present in one SI joint | 2 | 2 | 4 |
| Absent | 4 | 52 | 56 |
| Total | 14 | 54 | 68 |