A simplified fluid-sensitive MRI protocol for the hands to detect inflammation without contrast administration: a large study of symptom-free subjects from the general population as a reference for normality

Abstract

Objective MRI of the hands is valuable for risk-stratification in patients with arthralgia at-risk for developing rheumatoid arthritis (RA). Contrast-enhanced MRI is considered standard for assessment of RA, but has practical disadvantages. It also shows inflammation-like features in the general population, especially at older age, which should be considered in image interpretation. The modified-Dixon (mDixon) technique is reliable compared to contrast-enhanced sequences. Moreover, this short protocol without contrast-enhancement is patient-friendly. Whether it also shows inflammation-like features in the general population is unknown. We studied this to support accurate use in the clinic. Methods Two hundred twenty symptom-free volunteers from different age-categories were recruited from the general population and underwent mDixon MRI of both hands. Two readers independently scored MRIs for synovitis, tenosynovitis, and bone marrow edema (BME) in the metacarpophalangeal-joints (MCP) and wrists according to the RAMRIS. Features were considered present if scored by both readers; frequencies > 5% were considered relevant in terms of specificity and determined per age-category (< 40/40- < 60/ ≥ 60-years). Results Higher age correlated with higher BME-scores (p-value < 0.005), but not with synovitis and tenosynovitis-scores. BME (grade 1) occurred in some bones in people aged ≥ 60, 14% had BME in the lunate, 7% in metacarpal-1, and 6% in the trapezium. Synovitis and tenosynovitis did not occur in > 5%, except for grade-1 synovitis in the right distal radio-ulnar-joint in people aged ≥ 60 (11%). Conclusion On mDixon MRI, inflammatory features in the hands of the general population are rare. This facilitates image interpretation. To prevent overinterpretation, only several locations should be considered when evaluating people aged ≥ 60-years.