Magnetic resonance imaging, radiography, and scintigraphy of the finger joints: one year follow up of patients with early arthritis

Objectives-To evaluate synovial membrane hypertrophy, tenosynovitis, and er osion development of the 2nd to 5th metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints by magnetic resonance imaging in a group of pa tients with rheumatoid arthritis (RA) or suspected RA followed up for one y ear. Additionally, to compare the results with radiography, bone scintigrap hy, and clinical findings. Patients and methods-Fifty five patients were examined at baseline, of whom 34 were followed up for one year. Twenty one patients already fulfilled th e American College of Rheumatology (ACR) criteria for RA at baseline, five fulfilled the criteria only after one year's follow up, whereas eight maint ained the original diagnosis of early unclassified polyarthritis. The follo wing MRI variables were assessed at baseline and one year: synovial membran e hypertrophy score, number of erosions, and tenosynovitis score. Results-MRI detected progression of erosions earlier and more often than di d radiography of the same joints; at baseline the MRI to radiography ratio was 28:4. Erosions were exclusively found in patients with RA at baseline o r fulfilling the ACR criteria at one year. At one year follow up, scores of MR synovial membrane hypertrophy, tenosynovitis, and scintigraphic tracer accumulation had not changed significantly from baseline; in contrast, swol len and tender joint counts had declined significantly (p < 0.05). Conclusions-MRI detected more erosions than radiography. MR synovial membra ne hypertrophy and scintigraphy scores did not parallel the changes seen ov er time in clinically assessed swollen and tender joint counts. Although jo int disease activity may be assessed as quiescent by conventional clinical methods, a more detailed evaluation by MRI may show that a pathological con dition is still present within the synovium.