Pharmacokinetic Modeling of dynamic contrast-enhanced MRI of the hand and wrist in rheumatoid arthritis and the response to anti-tumor necrosis factor-α therapy

Dynamic contrast-enhanced MRI (DCE-MRI) of the hand an wrist was performed in 11 patients with rheumatoid arthriti twice before and once 2 weeks after treatment with anti-tumor necrosis factor (TNF)-alpha therapy. A rapid, T-1-weighted 3D spoiled gradient echo (SPGR) sequence was used for the dy namic imaging. T, estimation was performed using similar im ages obtained at different flip angles. The relative radiofre quency field was estimated from the known T, of the periartic ular fatty marrow. The arterial input function (AIF) wa measured at each examination, and normalized to the expectec plasma concentration to reduce partial volume effects. Synovia enhancement was modeled to yield values for K-trans, v(e), and v(p) Ktrans and v. showed good reproducibility. There was a signifi cant decrease of about 20% in K-trans after 2 weeks of treatment This study demonstrates the potential of DCE-MRI and phar macokinetic modeling to study early changes in inflammatory activity in rheumatoid arthritis following treatment.