Magnetic Resonance and Radiography in Rheumatoid Arthritis: Intermodality Comparisons of Erosion Detection

Abstract

<p><strong>BACKGROUND</strong>.<strong> </strong>Classically, radiography (x-ray) has been used to visualize the destructive effects of uncontrolled rheumatoid arthritis (RA) on articular bones. Both x-ray and magnetic resonance imaging (MRI) may be used to visualize erosive disease. The multi-slice and multi-planar characteristics of MRI provide greater detail per anatomy imaged than x-ray.</p> <p><strong>OBJECTIVE</strong>. The objective of this dissertation was to compare the relative merits of x-ray and MRI erosion detection.</p> <p><strong>METHODS</strong>. In Chapters 1 through 3, RA, its clinical management, and the role of diagnostic imaging were introduced. In Chapter 4, the overall objective was first investigated by evaluating the current state of knowledge using a systematic review. In Chapter 5, inter-rater reliability across four participating radiologists was investigated. In Chapter 6, reliability-adjusted evaluations were used to directly compare paired x-ray and MR images.</p> <p><strong>RESULTS</strong>. The systematic review indicated that x-ray has low sensitivity and high specificity for MRI erosions. The associations were dependent on RA symptom duration. The findings from the prospective studies conducted were consistent with the literature. In a patient-centred analysis, the proportion of patients with erosive disease detected on either modality was dependent on the anatomy compared. Despite similar proportions of patients with erosive disease detected in comparable diagnostic imaging sittings, the proportions were comprised of markedly different patients.</p> <p><strong>CONCLUSIONS</strong>. The literature comparing x-ray and MRI erosion detection was systematically reviewed. The dependence of the relative diagnostic test accuracy on symptom duration was highlighted. At the patient level of analysis, the greater number of anatomical sites examined on x-ray overcomes the superiority of MRI to detect erosions at the unit of measurement. The two modalities are complementary insofar that they detect erosive disease in distinct patients. Further investigation into the merit of imaging varied anatomy on MR and optimally accounting for inter-rater reliability in such comparisons is warranted.</p>