Tenosynovitis of the flexor tendons of the hand detected by MRI: an early indicator of rheumatoid arthritis.

OBJECTIVE: To evaluate the potential of MRI of finger and wrist joints for diagnosing early RA. MRI was evaluated as a stand-alone tool and in combination with ACR criteria and serum markers such as RF.
METHODS: Ninety-nine patients (31 men, 68 women; median age 46 years) with unspecified arthritis or suspected RA and negative X-ray findings were included. MR images of the hand and wrist of these patients were retrospectively evaluated for the presence of synovitis, erosions and tenosynovitis. The clinical diagnosis (early RA or non-RA) was made by a rheumatologist after clinical follow-up for 6-41 months. Clinical and laboratory data were collected from all patients.
RESULTS: Fifty-eight patients had a clinical diagnosis of RA and 41 were diagnosed as non-RA. Step-wise logistic regression of all MR parameters evaluated identified tenosynovitis of the flexor tendons to be the most powerful predictor of early RA (sensitivity = 60%, specificity = 73%). Including ACR criteria in the analysis, positive serum RF and tenosynovitis were the strongest predictors of early RA (sensitivity = 83%, specificity = 63%). When serum anti-cyclic citrullinated peptides (CCP), ANA and CRP were included as additional parameters, anti-CCP and flexor tenosynovitis were the strongest predictors of early RA (sensitivity = 79%, specificity = 73%).
CONCLUSIONS: Flexor tenosynovitis diagnosed by MRI of the hand is a strong predictor of early RA. Combining flexor tenosynovitis on MRI with positive serum anti-CCP or positive RF is an even stronger predictor of early RA.