Title:Early Identification of Sacroiliitis in Patients with Suspected Spondyloarthritis:
A Challenging Task
Volume: 19
Issue: 4
Author(s): Dorra Ben Nessib*, Mouna Chelli Bouaziz, Kaouther Maatallah, Mohamed Fethi Ladeb, Mohamed Montacer Kchir, Hend Riahi and Wafa Hamdi
Affiliation:
- Rheumatology Department, Kassab Orthopedics Institute, Mannouba, 2010, Tunisia
- Faculty of Medicine of Tunis, University Tunis el Manar, Tunis, Tunisia
- Research unit UR17SP04, 2010, Ksar Said 2010, Tunis, Tunisia; Institute, Mannouba 2010, Tunisia
Keywords:
Spondyloarthritis, sacroiliac joints, computed tomography, magnetic resonance imaging, diagnosis, sacroiliitis.
Abstract:
Objective: The purpose of this study was to assess the performance of computed tomography
(CT) scan and magnetic resonance imaging (MRI) for detecting sacroiliitis in nonradiographic
SpA (nr-SpA).
Methods: This cross-sectional monocentric double-blind study included 63 patients consulting for
symptoms suggestive of SpA between February 2014 and February 2017. Patients with conventional
radiographs showing a confirmed sacroiliitis (grade 3 or 4) were not included. Eligible patients
underwent CT and MRI of sacroiliac joints (SIJ). CT and MR images were interpreted by 2 experienced
musculoskeletal radiologists blinded to clinical and laboratory data. Two professors in rheumatology
blinded to radiologists’ conclusions analyzed clinical data, laboratory tests, HLA typing,
X-rays, CT and MRI images, and divided the patients into 2 groups: confirmed nr-SpA or no SpA.
This classification was considered the gold standard when analyzing the results.
Results: 46 women and 17 men were included in this study. 47 patients were classified as confirmed
nr-SpA (74.6%) and 16 patients as no SpA (25.4%). Sensitivity, specificity, and positive and
negative predictive values of CT and MRI for detecting sacroiliitis were, respectively, estimated at
71.7%, 71.4%, 89.2%, 43.5%, and 51.2%, 100%, 100%, and 40%. CT and MRI findings were
found to be statistically associated (p<0.001).
Conclusion: SIJ MRI is a highly specific method in the detection of sacroiliitis, but with a moderate
sensitivity. SIJ CT scan, usually known as the third option after radiography and MRI, has much
greater diagnostic utility than it has been documented previously.