Comparison of spinal anatomy between 3-Tesla MRI and CT-myelography under healthy and pathological conditions.

PURPOSE: In many centres both MRI and CT-myelography are performed for treatment planning of degenerative spine disease. More and more centres acquire 3-Tesla MRI scanners in which some artefacts, which lead to difficulties in image evaluation, are more pronounced than at 1.5 Tesla. Aim of this study was to compare spinal physiological and pathological anatomy between 3-Tesla MRI and CT-myelography and to review current imaging standards. METHODS: In 47 spinal segments commonly used 3-Tesla T2-weighted sequences and CT-myelography studies were evaluated retrospectively. Spinal canal, neural foraminal, spinal cord and disc protrusion diameters were measured. RESULTS: The spinal canal was found to be 10% tighter with the utilized MRI sequences, in comparison to CT-M and foraminal diameters were found to be 19.7% tighter in MRI. This was more pronounced in narrowed than in healthy segments. Spinal cord size and size of disc protrusions displayed no significant difference between MRI and CT-myelography. CONCLUSIONS: The main advantage of CT-myelography, in comparison to 3-Tesla MRI, is the reliable information about the bony structures. Soft tissues like the spinal cord or disc protrusions were visualised equivalently with both modalities concerning diameters.