[Osteoporotic stress fractures of the sacrum: MR-tomography findings].

PURPOSE: Evaluation of the morphologic appearance of sacral osteoporotic insufficiency fractures in MRI.

PATIENTS AND METHOD: 6 patients (5 female and one male, 54-80 years) with osteoporotic insufficiency fractures of the sacrum were examined with CT and MRI. Plain and contrast-enhanced T1- and T2-weighted spin-echo images were acquired, three patients were studied with T1-weighted gradient-echo-sequences with fat suppression.

RESULTS

Fracture-lines and sclerotic areas of the massae laterales were visible in 5 of 6 CT examinations, one patient showed no abnormalities of the sacrum on the initially performed CT scans. All patients had a diffuse bone marrow oedema of the fractured massae laterales with a decreased signal on the T1-weighted spin-echo images and an increased signal on the T1-weighted gradient-echo images with fat suppression and in the T2-weighted SE-sequences. Gadopentate dimeglumine enhanced MRI images showed a remarkable diffuse configurated high signal of the whole sacrum in bilateral fractures (H-pattern). An additional soft tissue mass could be excluded in each case.

CONCLUSION

Gadopentate dimeglumine enhanced MRI of sacral insufficiency fractures allows early diagnosis and helps to exclude intraosseous tumour formation.