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FRI0471 A comparative analysis of erosion repair in rheumatoid arthritis (RA) patients by magnetic resonance imaging (MRI) and hr-pqct
  1. A. Regensburger1,
  2. P. Koch1,
  3. S. Kraus1,
  4. C. Hecht1,
  5. M. Englbrecht1,
  6. J. Rech1,
  7. G. Schett1,
  8. F. Faustini1,
  9. S. Finzel1
  1. 1Department Of Internal Medicine 3, Rheumatology And Immunology, University Clinic Of Erlangen-Nuremberg, Erlangen, Germany

Abstract

Background The detection of bone erosions is fundamental both for monitoring of disease activity and therapy decisions in rheumatoid arthritis (RA). Recently, it could be shown by high-resolution peripheral quantitative computed tomography (HR-pQCT) that erosion repair is associated with bone apposition at the bottom of the erosion (“sclerosis”) [1;2]. MRI however is more widely available in clinical settings and used as a monitoring tool of disease activity in RA.

Objectives To investigate whether MRI allows visualization of sclerosis at the bottom of erosive lesions in comparison to HR-pQCT as a reference.

Methods 53 RA patients fulfilling the new ACR/EULAR criteria received a 1.5T MRI (Siemens, Vario) and an HR-pQCT (Scanco Medical AG, XtremeCT) of the metacarpophalangeal joints 2 and 3 of the clinically dominant hand. Prevalence of erosions as well as sclerosis was assessed in both imaging modalities in the coronal plane. All MRI- and CT-images were evaluated twice by two readers in a blinded fashion. Demographic and clinical data were collected for each patient.

Results 69.8% of patients were females, mean ±SD age was 53.15±15.90 years; mean disease duration ±SD was 34.9±64.5 months, and mean DAS28±SD was 3.61±1.81. Prevalence of RF and ACPA was 52.8% and 58.5% respectively.

A mean number of 66.5 erosions were detected by MRI per reading as compared to 81.5 erosions per reading by HR-pQCT (4 readings, 2 readers for each modality).

The average proportion of correctly classified non sclerosed lesions in the MRI compared to HR-pQCT was 94% (specificity), while the average proportion of correctly classified sclerosed lesions was 31% (sensitivity). Hence, our results show a good concordance of the two imaging modalities for absence of sclerosis, but poor agreement for presence of sclerosis.

On average, the observation of a “non sclerosed lesion” in the MRI was correct in 80.5% of cases after validation by HR-pQCT (negative predictive value-NPV), whereas it was 62% for “sclerosed lesions” in the MRI (positive predictive value-PPV).

Conclusions According to our results, MRI has limitations to detect repair of bone lesions in RA.

References

  1. Finzel S, Rech J, Schmidt S, et al. Ann Rheum Dis. 2011 Sep;70(9):1587-93.

  2. Finzel S, Rech J, Schmidt S, et al. Ann Rheum Dis. 2012 May 14. [Epub ahead of print]

Disclosure of Interest None Declared

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