THU0603 SUITABILITY OF PET-CT IN REFRACTORY POLYMYALGIA RHEUMATICA
Authors: Maria Emilia Corica, Patricia Moya, Alejandro Fernandez, Berta Magallares, Ignasi Gich, Ana Milena Millán Arciniegas, Hyesang Park, Monica Paola Sarmiento, Ana Laiz, Cesar Díaz-Torné, Josep Maria Llobet, Ivan Castellví, Hector Corominas
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Polymyalgia rheumatica (PMR) is characterized by pain in the shoulders and hips, elevation of acute phase reactants and a rapid response to treatment with corticosteroids. Currently, there is no specific test for its diagnosis, and it presents a wide differential diagnosis. Positron Emission Tomography - Computed tomography (PET-CT) is a non-invasive technique, capable of measuring metabolic activity by locating and quantifying glucose consumption. The use of PET-CT in the study of neoplastic, infectious or inflammatory processes suggests that it may be a suitable technique for the study of the differential diagnosis of patients with PMR. It is unknown if there are differences in the result of the technique in patients with debut PMR vs. patients with cortico-resistant PMR. <h3>Objectives:</h3> To describe the findings of PET-CT in patients with PMR. To analyze if there are significant differences between the results of patients with onset PMR and those of cortico-resistant PMR patients. <h3>Methods:</h3> This is a cross-sectional prospective study performed in a cohort of patients with PMR. Out of all patients with PMR who do follow up treatment in our centre, the patients selected for this study included those who underwent a PET scan at the time of diagnosis and those who presented corticosteroid resistance (patients who did not respond to conventional therapy with corticosteroids or with a relapse with doses &lt;7.5mg/day of prednisone or equivalent). Demographic, epidemiological data of the disease, treatment, as well as analytical parameters (CRP, ESR, Hematological and Biochemical) were collected from all the patients at the time the PET-CT was performed. For the categorical variables, the chi-square test or Fisher's exact test were used, as appropriate. In the case of quantitative variables, we used the comparison of the mean values, by means of a "t" test. The level of statistical significance was established for those values of p &lt;0.05. <h3>Results:</h3> 103 patients with a PMR diagnosis who had undergone a PET-TC were included, out of the total number of patients that we visited in our service. 52 (50.4%) patients had an onset PMR and 51 (49.9%) had PMR refractory to treatment. The demographic, clinical and serological characteristics of the patients at the time of PET-CT are shown in Table 1. The PET-CT showed a distribution of uptake compatible with the diagnosis of PMR in 73 (70.9%) patients, vasculitis of large vessels in 16 (15%) and contributed in the diagnosis of neoplastic processes in 5 (4.8%). Table 2 shows the final diagnoses. When analyzing the results of PET in patients with onset PMR vs. those who are corticosteroids resistant, no significant differences were observed in the final diagnoses (p = 0.078). <h3>Conclusion:</h3> PET-CT confirms the diagnosis of PMR in the significant majority of patients included in the study. In this cohort, PET-CT allowed to diagnose vasculitis of large vessels and neoplasms in 16% and 5% of the patients respectively. We did not observe differences in the PET findings in those patients who underwent a PET at the time of diagnosis vs. those who are corticosteroid resistant. <h3>References:</h3> [1] Ann Nucl Med. 2018 Oct;32(8):573-577; [2] Semin Nucl Med. 2017 Jul;47(4):408-424; [3] Br J Radiol. 2017 Aug;90(1076):20170198 <h3>Disclosure of Interests:</h3> Maria Emilia Corica: None declared, Patricia Moya: None declared, Alejandro Fernandez: None declared, Berta Magallares: None declared, Ignasi Gich: None declared, Ana Milena Millán Arciniegas: None declared, HyeSang Park: None declared, Monica Paola Sarmiento: None declared, Ana Laiz Consultant for: Lilly, Novartis, AbbVvie, MSD, UCB and Janssen, Speakers bureau: Lilly, Novartis, Abvvie, MSD, UCB and Janssen, Cesar Díaz-Torné: None declared, Josep Maria Llobet: None declared, Ivan Castellví Consultant for: I received fees less than 5000USD as a consultant for Kern and Actelion, Paid instructor for: I received fees less than 2000USD as a instructor for Boehringer -Ingelheim, Novartis and Gebro, Speakers bureau: ND, Hector Corominas: None declared