AB1311 SOFT TISSUE ENHANCEMENT IN MRI IN PATIENTS WITH GCA AND PMR
Authors: K. V. Guggenberger, M. Fröhlich, M. Schmalzing, B. Dasgupta, M. Gernert, P. P. Strunz, H. Labinsky, S. E. Serfling, R. A. Werner, T. Bley
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are considered to belong to a spectrum of inflammatory diseases with a broad overlap in clinical presentation called GPSD (GCA-PMR Spectrum Disease) [1]. Soft tissue abnormalities around the joints in patients with GPSD have already been detected using [<sup>18</sup>F]FDG PET/CT [2]. However, the resolution is limited for methodological reasons and soft tissue structures are often difficult to impossible to differentiate. Magnetic resonance imaging (MRI) offers the possibility of examining soft tissue structures with high resolution to better differentiate which structures are affected. <h3>Objectives:</h3> The aim of our study was therefore to analyze typical predilection sites of the soft tissue in GPSD with high-resolution MRI. <h3>Methods:</h3> Retrospective analysis of MRI examinations of patients with newly diagnosed GPSD according to current recommendations. High-resolution contrast-enhanced MRI was performed on a 3 Tesla scanner, using a T1-weighted VIBE sequence. The following structures were analyzed separately by two experienced radiologists, blinded to clinical data: Shoulders on both sides with glenohumeral joints, periarticular tendons, cervical spine. Enhancement was judged in a 4-point Lickert scale reaching from "no inflammation" to "surely inflamed" (0=no signs of inflammation, 1=mild contrast enhancement, unclear whether degenerative or inflammatory genesis, 2=accentuated contrast enhancement, suspicious of inflammatory changes, 3=strong contrast enhancement, highly suspicious of inflammatory changes). The analysis with regard to inflammatory changes was carried out in binary form; 0 and 1 were considered inflammation negative, 2 and 3 were considered inflammation positive. <h3>Results:</h3> 78 patients with GPSD [mean age 72±8 years; predominant vasculitis: 43(55.1%); predominant PMR 19(24.4%); overt symptoms of GCA and PMR 16(20.5%)] were analyzed. Analysis of the shoulders and spine revealed significant enhancement indicative of inflammatory activity in 51%, while only 44.9% had corresponding clinical symptoms. In detail, analysis revealed signs of glenohumeral synovitis in 27 patients (27/78=35%, 24 left side, 24 right side, 21 bilateral), shoulder joint effusion in 5 patients (5/78=6%, 5 left side, 4 right side, 4 bilateral), enhancement of the long biceps tendon in 20 patients (20/78=26%, 16 left side, 18 right side, 14 bilateral), enhancement of the subscapularis tendon in 33 patients (33/78=42%, 33 left side, 33 right side, 33 bilateral) and enhancement of the supraspinous ligament in 23 patients (23/78=29%) (Table 1). <h3>Conclusion:</h3> Signs of inflammation were found in more than half of the GPSD patients. Due to the high resolution of the MRI, various inflamed articular structures could be identified, including glenohumeral joints and various tendons. A new finding is that tendinitis can also be detected. MRI provides a differentiated overview of inflamed soft tissue structures in GPSD. <h3>REFERENCES:</h3> [1] Tomelleri, A., et al., <i>Disease stratification in GCA and PMR: state of the art and future perspectives.</i> Nat Rev Rheumatol, 2023. <b>19</b>(7): p. 446-459. [2] Fröhlich, M., et al., <i>Whole-Body [(18)F]FDG PET/CT Can Alter Diagnosis in Patients with Suspected Rheumatic Disease.</i> Diagnostics (Basel), 2021. <b>11</b>(11). <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> Konstanze V. Guggenberger: None declared, Matthias Fröhlich: None declared, Marc Schmalzing BMS, Novartis, AbbVie, AstraZeneca, Chugai/Roche, Janssen-Cilag, Gilead, Boehringer/Ingelheim, Mylan, onkowissen.de, Galapagos, EUSA-Pharma, Chugai/Roche, Hexal/Sandoz, Gilead, AbbVie, Janssen-Cilag, Boehringer/Ingelheim, onkowissen.de, EUSA-Pharma, Novartis, AstraZeneca, Amgen, medac, Lilly, Galapagos, UCB, Chugai, Novartis, Bhaskar Dasgupta: None declared, Michael Gernert: None declared, Patrick P. Strunz: None declared, Hannah Labinsky: None declared, Sebastian E. Serfling: None declared, Rudolf A. Werner: None declared, Torsten Bley: None declared.