[MR imaging of infected spondylodiskitis: interval signal change in vertebral body (including enhanced image of vertebral body)].

A retrospective evaluation of MRI was carried out in 22 patients with spondylodiskitis. Low signal intensity on T1-weighted images and high or low signal intensity on T2-weighted images were observed. Sixteen patients underwent follow-up examinations after the initial examination. Various signal changes in the vertebral body were recognized. The longer the period of follow-up, the less abnormal the signal intensity became on both T1- and T2-weighted images. Several cases showed no change in signal intensity. In all of 17 patients re-examined after injection of Gd-DTPA, infected vertebral bodies were enhanced. We classified the enhancing patterns of infected vertebral bodies in three types: A) homogeneous, B) homogeneous with strong enhancement adjacent to the end plate, C) inhomogeneous. Pyogenic spondylodiskitis tended to show patterns A or B, and tuberculous spondylodiskitis pattern C. The enhancement effect disappeared after normalization or remission of laboratory findings. In two cases, the enhancement effect remained even after laboratory findings became normal. Contrast MRI was useful for understanding infectious state.