Differentiation of tuberculosis and metastatic cancer in the spine using dynamic contrast-enhanced MRI.

PURPOSE: To investigate the differences between imaging features of spinal tuberculosis (TB) and metastatic cancer measured by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). The presentation of TB on convention MRI may not show the typical TB signs, and they may be mis-diagnosed as malignant diseases. DCE-MRI may provide additional information to help making differential diagnosis.

MATERIALS AND METHODS: DCE-MRI was performed in 24 TB and 22 metastatic cancer patients. The DCE kinetic pattern was determined as "wash-out", "plateau" or "persistent enhancement". The characteristic DCE parameters were calculated from the signal intensity time course. The two-compartmental pharmacokinetic model was used to obtain K (trans), which is the parameter associated with the delivery of MR contrast agents into the lesion, and k ep, which is the parameter associated with the distribution and clearance of contrast agents from the lesion.

RESULTS: Of the 24 TB, one case showed the wash-out kinetic pattern, 12 cases showed the plateau pattern, and 11 cases showed the persistent enhancement pattern. Of the 22 metastatic cancers, 12 cases showed wash-out, 7 cases showed plateau, and 3 cases showed persistent enhancement patterns. Compared to the metastatic cancer group, the TB group had a lower k ep (0.27 ± 0.15 vs. 0.49 ± 0.23 min(-1), P < 0.001). The ROC analysis showed that the area under the curve was 0.780 for k ep.

CONCLUSIONS: DCE-MRI may provide additional information for differentiation between spinal TB and metastasis, when their manifestations on conventional imaging were similar.