Article type
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Abstract
Background: The Cochrane Collaboration has decided to include systematic reviews of diagnostic test accuracy studies. We have completed a review on the accuracy of magnetic resonance imaging (MRI) to diagnose multiple sclerosis (MS).
Objective: To examine the accuracy of MRI in the diagnosis of MS. We focus on how we applied the Cochrane recommendations at each review stage.
Methods: We followed the methods of the draft Cochrane diagnostic reviewers' handbook. We searched electronic databases, bibliographies of included studies, and contacted experts. Diagnostic accuracy studies that compared MRI to a reference standard, or that compared MRI results in patients with and without MS, were eligible. Studies were excluded if they did not report data to construct a 2x2 table of test performance.
Results: We identified >6000 references; 29 studies were included. There was heterogeneity between studies in populations, MRI protocol, quality and the criterion used to define a positive result. Many studies published data for multiple criteria. Studies based on inappropriate patient spectra reported greater diagnostic accuracy (See Figure 1 on the following page). Of studies with appropriate spectra, five studies reported positive likelihood ratios (LR+) in excess of five, and one in excess of 10. Only six studies reported negative likelihood ratios (LR-) below 0.1. The Paty criteria were the most frequently evaluated (assessed in seven studies) and showed poor accuracy for ruling in disease (pooled LR+=2.3, considerable heterogeneity), and some potential for ruling out disease (pooled LR-=0.36, no heterogeneity). The Barkhof criteria were evaluated in two independent studies which reported poor accuracy (LR+=2.3, LR- = 0.5, no heterogeneity). The criterion-generating study reported higher accuracy.
Conclusions: The new Cochrane methods provided a practical framework for a diagnostic systematic review. The accuracy of MRI is not high enough to give likelihood ratios sufficient to rule in or rule out MS with high certainty.
Objective: To examine the accuracy of MRI in the diagnosis of MS. We focus on how we applied the Cochrane recommendations at each review stage.
Methods: We followed the methods of the draft Cochrane diagnostic reviewers' handbook. We searched electronic databases, bibliographies of included studies, and contacted experts. Diagnostic accuracy studies that compared MRI to a reference standard, or that compared MRI results in patients with and without MS, were eligible. Studies were excluded if they did not report data to construct a 2x2 table of test performance.
Results: We identified >6000 references; 29 studies were included. There was heterogeneity between studies in populations, MRI protocol, quality and the criterion used to define a positive result. Many studies published data for multiple criteria. Studies based on inappropriate patient spectra reported greater diagnostic accuracy (See Figure 1 on the following page). Of studies with appropriate spectra, five studies reported positive likelihood ratios (LR+) in excess of five, and one in excess of 10. Only six studies reported negative likelihood ratios (LR-) below 0.1. The Paty criteria were the most frequently evaluated (assessed in seven studies) and showed poor accuracy for ruling in disease (pooled LR+=2.3, considerable heterogeneity), and some potential for ruling out disease (pooled LR-=0.36, no heterogeneity). The Barkhof criteria were evaluated in two independent studies which reported poor accuracy (LR+=2.3, LR- = 0.5, no heterogeneity). The criterion-generating study reported higher accuracy.
Conclusions: The new Cochrane methods provided a practical framework for a diagnostic systematic review. The accuracy of MRI is not high enough to give likelihood ratios sufficient to rule in or rule out MS with high certainty.