Background Conventional radiography has shown an incremental benefit to assess the condition of the rheumatoid arthritis (RA), however it converts the view of three-dimensional structure to two-dimensional image. Tomosynthesis is a method to produce section imaging with X-ray equipment and allows to providing three-dimensional information at lower doses and lower cost than computed tomography (CT). Recent studies have demonstrated that tomosynthesis is superior to radiography for the detection of bone erosion in patients with RA.
Objectives To clarify the validity of tomosynthesis for evaluation of joint space narrowing and bone erosions in very early RA.
Methods 24 patients with early RA diagnosed by ACR/EULAR2010 (female 18, male 6), underwent radiography and tomosynthesis of hands and wrists, were included in this study. All of the patients were confidently diagnosed as definitive RA based on ACR 1987 classification criteria for diagnosing RA in the following observations. Mean age was 57.3 years old and mean duration of disease was 3.71 months. One rheumatologist scored joints of the hands and wrists using modified Total Sharp Score from two imaging modalities.
Results Scores for total joints evaluated were 112 vs 143 for joint space narrowing and 60 vs 142 for bone erosion in radiography and tomosynthesis respectively. The mean erosion scores per patient were 5.91±4.98 (range 0-14) with tomosynthesis, 2.5±4 (range 0-17) with radiography. The mean score was significantly higher with tomosynthesis than with radiography (P <0.005). Using Steinbrocker's staging system, 11 cases were Stage I and 13 cases Stage II assessed by radiography and 2 cases Stage I and 22 cases Stage II by tomosynthesis. In cases double negative for rheumatoid factor and anti-cyclic citrullinated peptide antibody, 3 cases in 6 were classified as Stage I by radiography, while all 6 cases were classified as Stage II by tomosynthesis.
Conclusions Tomosynthesis is useful for evaluation of bone erosions in patients with early RA. Especially, tomosynthesis contributes more greatly to making a diagnosis of double negative early RA compared to conventional radiography.
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Aoki T, et. Al. Am J Rhoentgenol. 2014
Disclosure of Interest None declared