Diffusion-weighted magnetic resonance imaging of sacral insufficiency fractures: comparison with metastases of the sacrum.
METHODS
Retrospective analysis of magnetic resonance imaging (MRI) for differentiating sacral insufficiency fractures from metastases of the sacrum.


OBJECTIVE
To determine if a steady-state free precession (SSFP) diffusion-weighted MRI is useful for differentiating sacral insufficiency fractures from metastases of the sacrum.


BACKGROUND
Conventional spin-echo sequence MRI is very sensitive for the detection of pathologic lesions in the sacrum, but the differential findings between sacral insufficiency fracture and metastasis are often not obvious because of the nonspecific changes of signal intensity. Another MR sequences for differentiation is needed.


METHODS
Fourteen patients with sacral insufficiency fractures and 8 patients with metastasis at the sacrum were examined with MRI. Both the diffusion-weighted MRI and the spin-echo MRI were performed in all patients. Diffusion-weighted MRI sequences were based on a SSFP sequence.


RESULTS
All the insufficiency fractures and metastasis at the sacrum revealed low signal intensity on T1-weighted MRI; low or high signal intensity was revealed on T2-weighted MRI. The contrast enhanced T1-weighted MRI showed strong enhancement at the sacrum in all cases of insufficiency fracture and metastasis. Diffusion-weighted MRI of the sacrum showed low signal intensity in all cases with sacral insufficiency fracture, but these images revealed high signal intensity in all cases with metastasis.


CONCLUSIONS
SSFP diffusion-weighted MRI is capable of differentiating benign sacral insufficiency fractures from metastatic tumors of the sacrum.
Byun
Woo Mok
WM
Department of Diagnostic Radiology, College of Medicine, Yeungnam University, Namku, Daegu, Korea. wmbyun@med.yu.ac.kr
Jang
Han Won
HW
Kim
Sang Woo
SW
Jang
Sung Ho
SH
Ahn
Sang Ho
SH
Ahn
Myun Whan
MW
D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008875:Middle Aged; D012189:Retrospective Studies; D012447:Sacrum / Q000473:pathology*; D016103:Spinal Fractures / Q000473:pathology*; D013125:Spinal Neoplasms / Q000473:pathology* / Q000556:secondary*