Internet hand x-rays: A comparison of joint space narrowing and erosion scores (Sharp/Genant) of plain versus digitized x-rays in rheumatoid arthritis patients

Abstract

Background: The objective of the study is to examine the reliability of erosion and joint space narrowing scores derived from hand x-rays posted on the Internet compared to scores derived from original plain x-rays.

Methods: Left and right x-rays of the hands of 36 patients were first digitized and then posted in standard fashion to a secure Internet website. Both the plain and Internet x-rays were scored for erosions and joint space narrowing using the Sharp/Genant method. All scoring was completed in a blind and randomized manner. Agreement between plain and Internet x-ray scores was calculated using Lin's concordance correlations and Bland-Altman graphical representation.

Results: Erosion scores for plain x-rays showed almost perfect concordance with x-rays read on the Internet (concordance 0.887). However, joint space narrowing scores were only "fair" (concordance 0.365). Global scores demonstrated substantial concordance between plain and Internet readings (concordance 0.769). Hand x-rays with less disease involvement showed a tendency to be scored higher on the Internet versions than those with greater disease involvement. This was primarily evident in the joint space narrowing scores.

Conclusions: The Internet represents a valid medium for displaying and scoring hand x-rays of patients with RA. Higher scores from the Internet version may be related to better viewing conditions on the computer screen relative to the plain x-ray viewing, which did not include magnifying lens or bright light. The capability to view high quality x-rays on the Internet has the potential to facilitate information sharing, education, and encourage collaborative studies.

Figure 1

Steps involved in the conversion of plain film x-rays to digital x-rays posted on a secure Internet web site.

Figure 2

Sharp with Genant modification scoring protocol for erosions and joint space narrowing.

Figure 3

Erosion scoring sites for Sharp score with the Genant modification.

Figure 4

Joint space narrowing sites for Sharp score with the Genant modification.

Figure 5

Lin's concordance for Internet and plain x-ray erosion scores.

Figure 6

Lin's concordance for Internet and plain x-ray joint space narrowing scores.

Figure 7

Bland-Altman data-scale assessment of the degree of agreement between plain and Internet global scores.

Figure 8

Bland-Altman data-scale assessment of the degree of agreement between plain and Internet joint space narrowing scores.

Figure 9

Bland-Altman data-scale assessment of the degree of agreement between plain and Internet erosion scores.