Radiology: Whole-body MR useful in detecting rare bone disease
Whole-body MRI, because it is more likely to show abnormalities, can help detect chronic recurrent multifocal osteomyelitis (CRMO), according to a study in the September issue of Radiology.

CRMO is a rare disease characterized by aseptic inflammatory lesions of bone in children and adolescents, the cause and pathogenesis of which are poorly understood.

In the study, Jan Fritz, MD, from the department of radiology and radiological science at Johns Hopkins University School of Medicine in Baltimore, and colleagues reviewed two-plane radiographs, clinical findings and lab data for 13 children (median age, 13 years) with CRMO. They evaluated lesion depiction, location and characterization and extraskeletal abnormalities, and compared MRI findings with clinical and lab data and radiographic results.

The authors whole-body MRI depicted 101 lesions—an average of eight affected anatomic sites per patient. It was seen most frequently in the distal femur (21 of 101 lesions), proximal tibia (17 of 101), distal tibia (14 of 101) and distal fibula (14 of 101). No lesions were found in the cranium, clavicle or upper extremity.

In tubular bones (90 anatomic sites) involvement of the metaphysis was present in 86 percent of patients; of the epiphysis, in 67 percent; of the diaphysis, in 14 percent; and of the apophysis, in 3 percent, according to Fritz and colleagues. For the 74 lesions located in the periphyseal region, a contiguous physeal relationship was present in 89 percent. Multifocality was present in all patients.

The authors found that CRMO “manifests with a whole-body MRI pattern of ill-defined edemalike lesions, most frequently located in the lower appendicular skeleton in a periphysial location.” Multifocality was virtually always present, most distributed symmetrically in the lower extremities and was frequently subclinical. “

“Whole-body MRI depicted this pattern at a higher rate than did radiography and clinical examination,” the authors reported, adding that whole-body MRI is more likely  to show abnormalities than are ESR and CRP values.

Whole-body MRI, the authors concluded, is useful in the radiation-free detection of asymptomatic and radiographically hidden multifocal sites of disease in patients with CRMO. The reason, the authors say, is that whole-body MRI identifies characteristic, ill-defined, edemalike, periphyseal osseous lesions predominantly in symmetrical lower extremity distribution.