The Application of MRI Subtraction in Imaging of Meninges

Objective To assess the potential of MRI subtraction in demonstration of normal meninges.Methods The appearance of normal meninges after administration of Gd-DTPA was evaluated in subtraction images (SI) and conventional T 1W images (T 1WI) in 45 normal volunteers in different anatomic levels (1～4). We evaluated the enhancement subjectively and measured them objectively.Results In 87% of the subjects, T 1WI showed short segments (3 cm) of meningeal enhancement,while continuous patterns were most frequently observed in SI. The differences of the dimensions and maximum length of enhanced meninges were statistically high significant in all levels(Ρ0.01). The relative signal intensities of enhanced meninges and pia mater vessels were significantly higher in SI than that in T 1WI. Mild to moderate enhancements were detected in both SI and T 1WI.Conclusion The subtraction technique can be used clinically for improving enhancement in MRI examinations of meninges.