Small bone lesions resembling erosions can frequently be found in bilateral wrist MRI of healthy individuals.

OBJECTIVE: To examine magnetic resonance imaging (MRI) scans for bone lesions typical of rheumatoid arthritis (RA) in the wrist joints of healthy individuals. METHODS: Thirty-one symptomless healthy persons (13/18 men/women), mean age 49 years (range 32-64 years), were included. MRI scans and radiographs of both wrists were obtained (62 wrists). The MRI scans and the radiographs were evaluated by two specialists according to the OMERACT recommendations and the Larsen method, respectively. RESULTS: MRI showed erosive-like lesions in either one or both wrists in 14 [45%, 95% confidence interval (CI) 27-64] out of 31 subjects. Altogether, 24 erosive-like changes were found in the 930 wrist bones evaluated (15 bones in each wrist). No more than two lesions per wrist were detected. All the changes were small (22 were grade 1 and two were grade 2; scale 0-10) and were found more often in the older subjects (55 vs. 43 years, p<0.001). Most lesions (54%) were located on the volar side of the wrist and adjacent to the ligament insertions. Intravenous administration of the contrast medium gadolinium diethylenetriaminepentaacetate (Gd-DTPA) was used in 10 subjects, and mild to moderate Gd-DTPA enhancement in the synovial compartments was seen in six of them: five had enhancement in both wrists and one in one wrist. The plain radiographs showed one erosive-like change in the wrist (pisiforme) that was not recorded with MRI. CONCLUSIONS: A few small bone lesions that could potentially be confused as erosions were detected in about half of the normal volunteers. These findings should always be evaluated with reference to the clinical picture.

Contrast-enhanced dynamic and static MRI correlates with quantitative 99Tcm-labelled nanocolloid scintigraphy. Study of early rheumatoid arthritis patients.

OBJECTIVE: The aim of this study was to evaluate the roles of contrast-enhanced dynamic and static magnetic resonance imaging (MRI) and quantitative 99Tcm-labelled nanocolloid (NC) scintigraphy in detecting wrist joint inflammation in early rheumatoid arthritis (RA) patients. METHODS: Twenty-eight early RA patients (median symptom duration 5 months, range 1-12 months) underwent MRI, NC scintigraphy, laboratory and clinical examinations. Static wrist MRI scans were retrospectively scored for synovitis, bone oedema and erosions by two independent readers using the recently published rheumatoid arthritis MRI scoring system (RAMRIS). Twenty NC scans were analysed quantitatively by measuring maximum 99Tcm-NC uptake in three small areas of each wrist. From the same locations on the wrists, dynamic MRI gadolinium-diethylenetriaminepenta-acetic acid (Gd-DTPA) enhancement rates (E-rate) were measured. The average 99Tcm-NC uptake of the whole wrist region was also measured and average E-rates were calculated. Correlations between MRI and NC scintigraphy measurements were calculated. Correlations between imaging methods of the wrist and the global measures of inflammation (laboratory and clinical examinations) were also assessed. RESULTS: Strong correlations emerged between maximal 99Tcm-NC uptake and MRI E-rates, reflecting similar performance of the methods in detecting local synovial inflammation. 99Tcm-NC uptake and MRI E-rate correlated with semiquantitative scoring of synovitis and bone oedema from static MRI scans. The erythrocyte sedimentation rate (ESR) correlated with MRI scores, E-rate and 99Tcm-NC uptake. No correlation between the clinical parameters and the imaging methods was detected. Inter-observer reliability for scoring synovial hypertrophy, bone oedema and bone erosions from static MR images were high (single-measure fixed-effects intra-class correlations 0.87, 0.93 and 0.91 respectively). Intra-observer reliability for E-rate and 99Tcm-NC measurements of 10 randomly picked scans was found to be high, with an intra-class correlation of 0.92; 95% confidence interval (CI) 0.84-0.96 and 0.99; 95% CI 0.98-1.00, respectively. CONCLUSIONS: Objective information about wrist joint inflammation can be obtained with contrast-enhanced dynamic MRI and quantitative 99Tcm-labelled NC scintigraphy. MRI also allows visualization and semiquantitative scoring of bone oedema and erosions of the wrist. Dynamic MRI and NC scintigraphy are safe and easy to perform, and they can be used in a long-term follow-up of rheumatoid patients.