Variables in the chronic nonbacterial osteomyelitis MRI scoring (CROMRIS) system14.
| CNO characteristics applicable for all CNO lesions | |
| Variables | Score values |
| Bone marrow hyperintensity | Absent, < fluid signal, and similar to fluid signal# |
| Signal size | Absent, < 25%, 25–50%, and > 50% of the bone involved |
| Soft tissue or periosteal hyperintensity | Absent or present |
| Bony expansion | Absent or present |
| Region-specific CNO features | |
| Variables of interest | Score values |
| Vertebral compression | Normal, some height loss, and vertebra plana |
| Kyphosis | Absent or present |
| Limb hypertrophy | Absent or present |
| Joint effusion | Absent or present |
| Grouping of bones | |
| Complex bones | Scapula, sacrum (combine S1–5 for each side), pelvis (ilium, periacetabulum, pubis/ischium), ribs, mandible, skull, patella, clavicle, divided into laterality (right and left side), and sternum (manubrium and sternal body) |
| Long bones | Humerus, ulna, radius, femur, tibia, fibula. These bones were divided anatomically into proximal epiphysis, proximal metaphysis, diaphysis, distal metaphysis, and distal epiphysis |
| Less-commonly affected bones | Hand: carpals, metacarpals, and phalanges; hindfoot: talus and calcaneus; fore/mid-foot: tarsals, metatarsals, phalanges |
| Spine | Sum of individual vertebral bodies from cervical to lumbar region with concomitant dichotomous scoring of abnormal signals within lateral and posterior spinal structures. |
↵# Additional scoring of confidence level as low, medium, or high. CNO: chronic nonbacterial osteitis; MRI: magnetic resonance imaging.