Is Nørgaard's Radiological Sign for Early Rheumatoid Arthritis Reliable?: An Epidemological Approach

Abstract

From two population surveys in Sweden and Iceland, hand X-rays of 170 persons between 34 and 70 years of age were read by three sets of observers. Special attention was paid to the features of N9rgaard's sign, namely small erosions at the base of the lateral ends of the phalanges, visible only in the oblique projection, attributable to earIy rheumatoid arthritis. The 1966 criteria for rheumatoid artMtis were applied and two rheumatoid factor tests were wed (AFT and SSCT). Only 16% of the persons were graded identically for X-ray findings by the three sets of observers. In population contexts, N9rgaard's sign was shown to have poor reproducibillty and low specificity and not to contribute significanay to the radiological diagnosis of rheumatoid arthritis. The "overdiaposis" of radiological signs of rheumatoid arthritis made by the radiologists might be due to ethnical difference in the bone structure of the populations examined. Scand J Rheumatology 2Scand J Rheumatol Downloaded from informahealthcare.com by QUT Queensland University of Tech on 11/21/14 For personal use only. Erik Allander, Avd. for socialmedicin, Karolinska Institutet, Stockholm, Sweden Scand J Rheumatol Downloaded from informahealthcare.com by QUT Queensland University of Tech on 11/21/14 For personal use only.

The value of conventional views and radiographic magnification in evaluating early rheumatoid arthritis

“…The Brewerton and reverse oblique, the 2 least sensitive in evaluating the other 3 abnormalities, performed better than the PA in the detection of erosive disease. Similarly, Norgaard has argued that the reverse oblique is more sensitive in detecting erosions (14,15), although others have disputed that claim (16,17). Our findings would also indicate that the PA may not be the single best conventional film for detecting erosions.…”

The ‘pre-erosive’ radiologic signs of rheumatoid arthritis in soft tissue radiography of the hands

“…13. A n epidemiologic app r o a c h to 170 persons from Iceland and Sweden subsequently showed the p o o r reproducibility and low specificity of this sign [1]. Note the sclerotic margins of the punched-out areas In a prospective study of 202 patients having 'early R A ' , periarticular ' p u n c h e d -o u t ' areas were found to be a statistically highly significant sign in the prediction of R A [40].…”