MR-IMAGING OF THE LOWER SPINE - DIFFERENTIATION BETWEEN INFECTIOUS AND MALIGNANT DISEASE

The findings on MR imaging of 28 patients with spinal infection and 40 patients with spinal malignant disease were compared. Spinal infectio ns involved one to 4 vertebrae, usually (23/28) 2 vertebrae. The poste rior elements were involved with certainty in 26/40 patients with mali gnancy but in none with infection. In the latter group, the posterior elements might have been involved in 3/28. The intervertebral disk bet ween the infected vertebrae was involved in 26/28 patients and 21/28 h ad a paravertebral mass. Spinal malignancies affected the vertebrae al one in 19 patients and paravertebral extension was found in 21/40 pati ents. The intervertebral disk was involved only in one patient with ma lignancy. The differences in the distribution of the MR findings betwe en spinal infection and spinal malignancy were highly significant (p<0 .001). The highest signal intensity of the infectious lesions on T2-we ighted images was equal to or higher than that of the cerebrospinal fl uid (CSF) in 26/28 patients. In contrast, the sinal intensity of the m alignant lesions was hypointense as compared to the CSF in 29/40 patie nts (p<0.001). MR is a useful method for differentiating between infec tion and malignancy in the lower spine; T2-weighted images are especia lly valuable for differentiation.