Table 1.
Utility of Early MRI Screening for Extensive Osteonecrosis Affecting ≥ 30% of the Epiphyseal Surface in Pediatric Patients Treated With Fixed Doses and Schedules of Glucocorticoids for Acute Lymphoblastic Leukemia
| Patient Group | No. of Hips |
Sensitivity (%) |
Specificity (%) |
No. of Joints Needed to Screen |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total* | True-Positive Screening | False-Positive Screening | False-Negative Screening | True-Negative Screening | Positive Final Outcome | Rate | 95% CI | Rate | 95% CI | No. | 95% CI | |
| All patients* | 744 | 37 | 4 | 7 | 696 | 44 | 84.1 | 70.6 to 99.8 | 99.4 | 98.5 to 99.8 | 20.1 | 14.8 to 27.6 |
| Age at diagnosis, years | ||||||||||||
| 1-10 | 595 | 3 | 4 | 1 | 587 | 4 | 75.0 | 30.1 to 95.4 | 99.3 | 98.3 to 99.7 | 198 | 67.9 to 583 |
| 11-20 | 149 | 34 | 0 | 6 | 109 | 40 | 85.0 | 70.2 to 94.3 | 100 | 96.7 to 100 | 4.4 | 3.3 to 5.9 |
Abbreviation: MRI, magnetic resonance imaging.
Although 462 patients had at least one screening MRI and are included in calculations of cumulative incidence and risk factors for osteonecrosis, only 374 patients (744 joints) had both an early screening MRI and a final screening MRI and are included in calculations of the sensitivity, specificity, and the number of joints and patients needed to screen to identify each case of extensive osteonecrosis. In all patients, MRI was performed on both hips when it was performed. To understand the apparent discrepancy between 374 patients and 744 joints, see Screening Outcomes under Results.