PP1. REPETITIVE 18-FLUORODEOXYGLUCOSE POSITRON EMISSION TOMOGRAPHY IN ISOLATED POLYMYALGIA RHEUMATICA: A PROSPECTIVE STUDY IN 35 PATIENTS

Abstract

Objective: To study fluorodeoxyglucose (FDG)-deposition in different vascular beds and in the large joints of patients with isolated polymyalgia rheumatica (PMR) and to investigate whether there is a relation between FDG-positron emission tomography (PET) results and risk of relapse. Methods: All consecutive patients with isolated PMR underwent a FDG- PET scan before treatment with steroids was started and – if logistics allowed – at 3 and 6 months. PET-scans were scored at 7 different vascular areas and a total vascular score (TVS) was calculated, ranging from 0 to 21. FDG uptake in the shoulders, the hips and the processi spinosi of the vertebrae was scored as 0 (no uptake), 1 (moderate uptake) or 2 (intense uptake). Results: Thirty-five patients entered the study. At diagnosis, vascular FDG-uptake was noted in 11 patients (31%), predominantly at the subclavian arteries. Mean TVS was low. FDG-uptake in the shoulders was noted in 94% of patients, in the hips in 89% and in the processi spinosi of the vertebrae in 51%. The intensity of FDG-uptake in the large vessels or in the shoulders, hips or processi spinosi did not correlate with the risk of relapse. Conclusions: Only 1 in 3 patients has a (moderately) increased vascular FDG-uptake, especially in the subclavian arteries. The vast majority has inflammation of shoulders and hips and half of them have increased FDG-uptake at the processi spinosi. Results of FDG-PET scans in patients with PMR do not correlate with their risk of relapse.