Contrast enhancement of normal intervertebral disks: time and dose dependence.

PURPOSE To determine the dose of contrast medium and the imaging strategy sufficient to detect diffusion of low-molecular-weight gadolinium-containing contrast media into normal intervertebral disks. METHODS In 11 rabbits, sequential MR images were obtained of the spine for 120 minutes after intravenous injection of gadopentetate dimeglumine in doses of 0.1 to 2.8 mmol/kg. Images were inspected for evidence of contrast enhancement. Signal intensity was measured and plotted as a function of time and dose. RESULTS Contrast enhancement was detected by inspection of images and by measurement in animals receiving doses of 0.3 mmol/kg and larger. CONCLUSIONS Diffusion of gadolinium-containing chelates into the intervertebral disk can be detected with clinically used doses of commercially available contrast medium. Therefore, with MR and a gadolinium-containing contrast medium, diffusion into intervertebral disks can be studied.