Rheumatologists Overcall Sacroiliitis on X-ray and MRI in Axial Spondyloarthritis Patients: Data from the BelGian Inflammatory Arthritis and SpoNdylitis cohorT (Be-GIANT)

Abstract

patients with high clinical risk for MSG lymphoma underwent US and histological examination. More recently, in the work up of LSG biopsy, UHFUS was introduced to scan LSG and to locate biopsy sites. MSG-US was performed with an 18 MHz probe, whereas UHFUS-LSG was performed with a 70 MHz probe. OMERACT score was assessed both in MSG and LSG. For suspected lesions additional ultrasonographic features were also analyzed. Patients' clinical, biological, and histological features were collected. Results: We included 45 consecutive pSS patients with suspected MSG-NHL (MSG group) and 34 consecutive pSS patients undergoing UHFUS-guided LSG biopsy (LSG group). Of suspected MSG-NHL, the diagnosis of NHL was confirmed in 14 patients (17 parotids and 1 submandibular gland) whereas out of 34 pSS patients undergoing UHFUS-guided LSG biopsy (LSG group), 5 atypical inflammatory infiltrate or LSG-NHL were detected (2/5 atypical inflammatory infiltrate and 3/5 labial NHLs, respectively). In MSG group, 16 MSG-NHL glands presented an OMERACT grade 3 while the other two MSG-NHL glands had a score 2. MSG-NHL appeared as very hypoechoic lesions with posterior enhancement, hyper-echoic strands or septa and a high peri/intralesional doppler. In LSG group, all 5 atypical inflammatory infiltrate/LSG-NHL had OMERACT score 3, whereas the highest OMERACT score was detected only in 10/29 no-LSG-NHL patients (p=0.05). Of 5 typical inflammatory infiltrate/LSG-NHL patients, 4 presented a diffuse change, while the other patient presented a focal lesion. Atypical inflammatory infiltrate/LSG-NHL appeared as very hypoechoic lesion with high perilesional doppler. Conclusion: LSG-NHL showed US features similar to MSG-NHL. Patients with an OMERACT score 3 in both their MSG and LSG, presenting very hypoechoic areas and high perilesional doppler, deserve a careful screening for lymphoma. Background/Purpose: To investigate (1) agreement between local and central reading of sacroiliac joint images (X-ray and magnetic resonance imaging [MRI]) from axial spondylarthritis (axSpA) patients, and (2) to explore potential differences between patients diagnosed in an academic hospital compared to community centres.