Langerhans' cell histiocytosis of the spine: use of MRI in guiding biopsy

The MRI features of two cases of spinal Langerhans' cell histiocytosis with multilevel involvement are presented in which MRI was of help in different iating active from inactive healing lesions by the demonstration of signal changes in the vertebral body marrow of the active lesion, manifest as low signal intensity on T1-weighted sequences and high signal intensity on T2-w eighted sequences. This distinction could not be made by plain radiography or bone scintigraphy. In cases where biopsy is required for diagnosis, MRI is recommended to guide the biopsy towards levels suggestive of active invo lvement.