Assessment of disease activity in patients with rheumatoid arthritis using optical spectral transmission measurements, a non-invasive imaging technique

Ann Rheum Dis. 2016 Mar;75(3):511-8. doi: 10.1136/annrheumdis-2015-207315. Epub 2015 Oct 9.


Objectives: In rheumatoid arthritis (RA), treat-to-target strategies require instruments for valid detection of joint inflammation. Therefore, imaging modalities are increasingly used in clinical practice. Optical spectral transmission (OST) measurements are non-invasive and fast and may therefore have benefits over existing imaging modalities. We tested whether OST could measure disease activity validly in patients with RA.

Methods: In 59 patients with RA and 10 patients with arthralgia, OST, joint counts, Disease Activity Score (DAS) 28 and ultrasonography (US) were performed. Additionally, MRI was performed in patients with DAS28<2.6. We developed and validated within the same cohort an algorithm for detection of joint inflammation by OST with US as reference.

Results: At the joint level, OST and US performed similarly inproximal interphalangeal-joints (area under the receiver-operating curve (AUC) of 0.79, p<0.0001) andmetacarpophalangeal joints (AUC 0.78, p<0.0001). Performance was less similar in wrists (AUC 0.62, p=0.006). On the patient level, OST correlated moderately with clinical examination (DAS28 r=0.42, p=0.001), and US scores (r=0.64, p<0.0001). Furthermore, in patients with subclinical and low disease activity, there was a correlation between OST and MRI synovitis score (RAMRIS (Rheumatoid Arthritis MRI Scoring) synovitis), r=0.52, p=0.005.

Conclusions: In this pilot study, OST performed moderately in the detection of joint inflammation in patients with RA. Further studies are needed to determine the diagnostic performance in a new cohort of patients with RA.

Keywords: Disease Activity; Magnetic Resonance Imaging; Rheumatoid Arthritis; Synovitis; Ultrasonography.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Arthralgia / diagnosis
  • Arthritis, Rheumatoid / diagnosis*
  • Case-Control Studies
  • Female
  • Hand Joints / diagnostic imaging
  • Hand Joints / pathology*
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Optical Imaging
  • Pilot Projects
  • Severity of Illness Index
  • Spectrum Analysis
  • Synovitis / diagnosis*
  • Ultrasonography