Bone Abstracts

Objectives: The main aim of the study is to describe a new method of quantitative, MRI-based assessment of inflammation in children with chronic recurrent multifocal osteomyelitis (CRMO).

General hypothesis: The main hypothesis is that the bone marrow edema, as detected in CRMO with MRI, can be quantified to aid early diagnosis and help identify clinically silent lesions.

Methods: We performed a retrospective analysis of static MRI scans from six children with CRMO at the Royal National Orthopaedic Hospital. Five of the patients were female and one male. They were 4–14 years of age and they all had multiple lesions on whole-body MRI. The MRIs were further analysed with a specialized computer software. Analysis of static MRI (STIR) was based on a computer-guided, manually selected, region-of-interest (ROI) method, and quantitative, pixel-by-pixel processing was performed. We looked at the bone marrow signal intensity (SI), described as bone marrow edema (BME) in conventional fat suppression STIR sequences. We calculated the changes in intensity from BME lesions (lesion MI–mean intensity), to areas of healthy bone marrow from the same patient as internal control (internal control MI–mean intensity). This calculation is presented as ratio (lesion MI by internal control MI) and also as percentage changes.

Results: There is a persistent increase in signal intensity in the areas of bone marrow edema, compared to control, ranging from 1.26 to 3.35 ratio (mean 2.25), corresponding to percentage changes from 25.67 to 235.06% (mean change 125.41%). Our results show that this method can detect bone inflammation with at least the same sensitivity as STIR MRI. They also show that it is possible to capture inflammatory bone lesions that have gone undetected in conventional MRI, which are depicted as ‘hot spots’. Finally, they show various degrees of intensity of the inflammatory process, which can be used to ‘titrate’ inflammation in the bone.

Conclusions: This method can detect and titrate inflammation from bone marrow edema lesions. Further research is needed to formally evaluate the sensitivity and specificity of the method.

Disclosure: The authors declared no competing interests.