Diagnosis of insufficiency fractures caused by severe osteoporosis on bone scintigraphy

Objectives To explore bone scintigraphic characteristics of insufficiency fractures caused by severe osteoporosis, and correlate its occurrence to bone mineral density (BMD).

Methods From Jun 2007 to Dec 2010, there were a total of 1222 patients underwent bone scintigraphy for ruling out bone metastases and had positive results, which excluded those with history of skeleton malignancy, skeleton metabolic disease, trauma and osteoarthritis. Fifty-three of the patients with insufficiency fractures caused by severe osteoporosis were studied, including 40 females and 13 males, and their age ranged from 29 to 87 years (mean, 69years). All patients were followed for more than one year, and the clinical diagnosis was based on the serologic test, imaging examination and BMD measurement. Incidence of insufficiency fractures was noticed, its imaging feature was analyzed; and the occurrence of fractures was correlated to the BMD of the lumbar and femoral neck.

Results Insufficiency fracture occurred in 4.3% of the patients in the group, which include 28 with primary osteoporosis, 17 with immune system disease and 8 with beast cancer and a long term of anti-estrogen treatment. On bone scintigraphy, single or double lesions were found in 20 patients, and multiple lesions, in 33. Most of the fractures occurred in vertebra and ribs, and it also can be seen in pubis, sacrum and humerus. Lesions all showed high uptakes and shipped as “linear” in vertebra, “spot” in ribs, and “H” type in sacrum, whereas, no expansive growth or distribution along the skeleton courser was found. BMD measurement showed that all patients had osteoporosis, the mean T score for lumbar and femoral neck was -3.2±1.0 and -3.3±0.9, respectively. T scores in lumbar and femoral neck were both lower in the patients with multiple lesions than those with one or two lesions.

Conclusions Insufficiency fracture caused by severe osteoporosis can be found in 4.3% patients with positive bone scintigraphy, and usually presented as multiple lesions. The image manifestation and BMD measurement can help the differential diagnosis