Magnetic resonance imaging in osteomalacic insufficiency fractures of the pelvis

AIMS: To report the magnetic resonance imaging (MRI) findings of osteomalacic insufficiency fractures of the pelvis. MATERIALS AND METHODS: In all, 12 persons presenting with chronic pelvic pain and with a definitive diagnosis of osteomalacia (OM) were enrolled in this study. Radiological work-up included direct radiographs (n = 12), computed tomography (n = 5), scintigraphy (n = 12) and MRI (n = 12). The location of the insufficiency fractures and corresponding MRI appearances were evaluated. Depending on the presence or absence of signal intensity around the fractures, the lesions were grouped into active and chronic forms. RESULTS: A total of 34 insufficiency fractures were depicted on imaging studies. MRI demonstrated 33 of the lesions. All the insufficiency fractures were seen as a hypointense lines or fissures on T1- and T2-weighted and STIR MR images. There was a high frequency of insufficiency fractures at the sacrum and iliac bone (16/34, 47%). Overall, 11 chronic-type (no abnormal signal intensity around the fissure) and 22 active-type (abnormal signal intensity around the fissure) insufficiency fractures were detected by MRI. Follow-up MR examinations of 2 subjects showed that abnormal signal intensity had disappeared after appropriate treatment. CONCLUSION: The results of this study showed that the iliac and sacral bones are frequently involved in patients with OM. MRI can determine the clinical activity of the disease, and can monitor the response to treatment of the active type of insufficiency fractures.