Usefulness of dynamic contrast-enhanced magnetic resonance images for distinguishing between pyogenic spondylitis and tuberculous spondylitis

Purpose Dynamic contrast-enhanced (DCE)-MRI is used for examining the features of malignant tumours in radiology, and we can obtain more information in terms of the diffusion of the media over the course of time. The purpose of this study was to clarify the usefulness of DCE-MRI for distinguishing pyogenic spondylitis (PS) and tuberculous spondylitis (TB). Methods Forty-five consecutive patients diagnosed with PS (68.6 +/- 11.1 years old, males 30 and females 15) and 14 with TB (73.9 +/- 9.1 years old, males 6 and females 8) were involved. DCE-MRI consisted of serial six sagittal images which were taken every 20 s after intravenous gadolinium administration. Degree of enhancement, presence of epidural abscess, presence of necrosis in vertebra, presence of enhancement in disc lesion, pattern of diffusion, and maximum contrast index were examined and compared between PS and TB. Results Degree of enhancement, percentage of epidural abscess, and percentage of necrosis in vertebra were 2.1 +/- 0.5 and 1.8 +/- 0.8, 60.7% and 100%, 50.0% and 66.7% for PS and TB, respectively, without statistical difference. Maximum contrast index, percentage of the diffusion pattern from the disc, and percentage of enhanced disc were 108.1 +/- 22.3 and 78.2 +/- 35.6 s, 89.3% and 0%, and 53.6% and 0% for PS and TB, respectively, with statistical significance. Conclusions This study indicated that longer maximum contrast index, higher likelihood of diffusion pattern from the disc, and higher likelihood of enhanced disc are more specific to PS than TB. This less invasive imaging technique is useful for more accurate diagnosis of PS and TB. Graphic abstract These slides can be retrieved under Electronic Supplementary Material.