A retrospective study of 96 cases comparing x-ray radiography and MRI for diagnosing paediatric subacute osteomyelitis

Background Subacute hematogenous osteomyelitis (SAHOM) presents a diagnostic challenge, requiring robust validation of imaging accuracy. Purpose To determine the superior diagnostic performance of MRI vs. radiography (x-ray) in detecting and classifying SAHOM. Methods This retrospective study included 96 proven SAHOM cases (2000–2025). Demographic data, involved bones, and microbiological results were collected. Two independent readers assessed x-Ray and MRI for detection of SAHOM, and classified lesions using the modified Roberts classification. Inter-reader disagreements were resolved by consensus. Sensitivity of x-Ray was evaluated against MRI as the reference standard. Results x-ray radiographs and MRI from 96 proven cases of SAHOM involving 49 males and 47 females (mean age 47.1 ± 47.6 months) were evaluated. MRI was markedly more sensitive, with significantly more correct imaging findings than radiography for detecting the features of SAHOM (100% vs. 47.9%). Moreover, 21.3% of the SAHOM lesions on x-ray radiography were misclassified. Radiography's limitations were most pronounced for lesions of the spine, tarsal/carpal bones, pelvis, and epiphysis, as well as for infections caused by Kingella kingae ( K. kingae ). Conclusions MRI is a more effective method than x-ray radiography for diagnosing SAHOM; it reveals lesions with higher definition and enables their more precise classification. This is especially true of lesions involving the spine, pelvis, tarsal or carpal bones, and the epiphysis, or when SAHOM is caused by K. kingae . MRI also provides much better imaging of the involvement of growth cartilage and damage to articular cartilage.