PET/CT imaging in polymyalgia rheumatica: praepubic 18F-FDG uptake correlates with pectineus and adductor longus muscles enthesitis and with tenosynovitis
Article Category: Research Article
Online veröffentlicht: 14. Jan. 2017
Seitenbereich: 8 - 14
Eingereicht: 29. Aug. 2016
Akzeptiert: 14. Dez. 2016
DOI: https://doi.org/10.1515/raon-2017-0001
© 2017 Zdenek Rehak, Andrea Sprlakova-Pukova, Zbynek Bortlicek, Zdenek Fojtik, Tomas Kazda, Marek Joukal, Renata Koukalova, Jiri Vasina, Jana Eremiasova, Petr Nemec
This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Background
The role of 18F-fluorodeoxyglucose positron emission computed tomography (18F-FDG PET/CT) is increasing in the diagnosis of polymyalgia rheumatica (PMR), one of the most common inflammatory rheumatic diseases. In addition to other locations, increased 18F-FDG accumulation has been detected in the praepubic region in some patients. However, a deeper description and pathophysiological explanation of this increased praepubic accumulation has been lacking. The aim of the presented study is to confirm a decrease in praepubic 18F-FDG accumulation in response to therapy and to describe potential correlations to other 18F-FDG PET/CT scan characteristics during the course of disease. As a secondary objective, we describe the pathological aspects of the observed praepubic 18F-FDG uptake.
Patients and methods
A retrospective review of patients with newly suspected PMR undergoing baseline and follow up 18F-FDG PET/CT between February 2010 and March 2016 is given. Those with a visually detected presence of praepubic 18F-FDG accumulation were further analysed. The uptake was assessed visually and also semi-quantitatively in the defined region of interest by calculation of target-to-liver ratios. Other regions typical for PMR were systematically described as well (shoulders, hips, sternoclavicular joints, ischiogluteal bursae, spinous interspaces).
Results
Twenty-three out of 89 screened patients (26%) presented with initial praepubic 18F-FDG PET/CT positivity, 15 of whom also underwent follow up 18F-FDG PET/CT examination. Five out of 15 patients presented with increased 18F-FDG accumulation in large arteries as a sign of giant cell arteritis. During follow up examination, decrease in 18F-FDG accumulation caused by therapeutic intervention was observed in all evaluated locations in all analysed patients and no new positivity was indicated, including periarticular, extraarticular tissues or target large vessels. Praepubical accumulation of 18F-FDG was diminished in all patients (15/15, 100%) after treatment with steroids.
Conclusions
Increased praepubic 18F-FDG uptake in patients with PMR is relatively common and this region should be systematically evaluated during differential diagnosis of rheumatic and malignant disease. Praepubic inflammation is probably related to enthesitis and tenosynovitis at the origin of pectineus and adductor longus muscles ventrally from the pubis.