Role of¹⁸F-FDG PET/CT in Large Vessel Vasculitis and Polymyalgia Rheumatica

Abstract

Learning Objectives: On successful completion of this activity, participants should be able to (1) understand the role of 18 F-FDG PET/CT for diagnosis and therapy monitoring of LVV and PMR; (2) learn about the strengths and limitations of 18 F-FDG PET/CT in LVV and PMR, including the pitfalls;(3) know the PET procedures around LVV and PMR; and (4) realize the potential of more specific PET tracers in LVV and PMR, particularly in monitoring disease activity. Financial Disclosure: Kornelis van der Geest received a speaker fee from Roche and research support from AbbVie. In accordance with ACCME Revised Standards for Commercial Support and SNMMI Conflict-of-Interest Policy, the authors have indicated no other relevant relationships that could be perceived as a real or apparent conflict of interest. Disclosure of a relationship is not intended to suggest or to condone bias but is made to provide participants with information that might be of potential importance to their evaluation of the activity. CME Credit: SNMMI is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to sponsor continuing education for physicians. SNMMI designates each JNM continuing education article for a maximum of 2.0 AMA PRA Category 1 Credits. Physicians should claim only credit commensurate with the extent of their participation in the activity. For CE credit, SAM, and other credit types, participants can access this activity through the SNMMI website (http://www.snmmilearningcenter.org) through April 2026.Systemic vasculitides comprise a group of autoimmune diseases affecting blood vessels, including large vessel vasculitis (LVV) and medium-sized vessel vasculitis such as giant cell arteritis (GCA) and Takayasu arteritis (TAK). GCA frequently overlaps with polymyalgia rheumatica (PMR), a rheumatic inflammatory condition affecting bursae, tendons or tendon sheaths, and joints. 18 F-FDG PET/CT plays an important role in the diagnostic work-up of GCA, PMR, and TAK and is increasingly used to monitor treatment response. This continuing education article provides up-to-date guidance on the role of 18 F-FDG PET/CT in patients with LVV, medium-sized vessel vasculitis, and PMR. It provides a general introduction on the clinical presentation and challenges in the diagnostic work-up of LVV and medium-sized vessel vasculitis, with a focus on the 2 major LVV subtypes: GCA, including PMR, and TAK. Next, practice points to perform and interpret the results of 18 F-FDG PET/CT are described in line with the published procedure recommendations. Furthermore, the diagnostic performance and its role for treatment monitoring are discussed, taking into account recent international recommendations for the use of imaging in LVV and medium-sized vessel vasculitis in clinical practice. This is illustrated by several clinically representative PET/CT scan examples. Lastly, knowledge of limitations and pitfalls is essential to understand the role of 18 F-FDG PET/CT in LVV, medium-sized vessel vasculitis, and PMR. Challenges and opportunit...

New thresholds in semi-quantitative [18F]FDG PET/CT are needed to assess large vessel vasculitis with long-axial field-of-view scanners

“…As such, there is a clear rationale to pursue a semi-quantitative evaluation in PET imaging interpretation, although to-date there is still insufficient evidence of a superiority over visual interpretation only [ 3 , 14 ]. However, another two questions arise: (1) what is the best semi-quantitative parameter and with which separator?…”

“…18 F-2-Fluoro-2-deoxy- d -glucose ([ 18 F]FDG) positron emission tomography/computed tomography (PET/CT) has secured an important role in the diagnosis and follow-up of large vessel vasculitis (LVV) [ 1 – 3 ]. Current guidelines recommend a visual evaluation of [ 18 F]FDG PET with a standardized grading system based on the comparison with liver uptake, wherein uptake in a vessel equal to that of the liver is rated as possibly positive (grade 2) and uptake greater than that in the liver as definitively positive (grade 3) [ 4 ].…”

PET-CT in Polymyalgia Rheumatica: When and for what—A Critical Review

“…All of these observations are in line with the recommendations put forward by van der Geest et al, who highlight the importance of evaluating multiple anatomic sites, including the shoulders, sternoclavicular joints, interspinous bursae, ischial tuberosities, hips, and greater trochanters, using 18F-FDG PET-CT to detect suspected PMR. As these authors concluded, the significant FDG uptake at multiple anatomic sites is a strong indication of PMR [42,58]. In this regard, Slart et al confirmed that 18F-FDG PET-CT is highly effective to identify inflammation in large vessels, offering precise imaging that correlates well with clinical and histopathological findings [58].…”

“…As these authors concluded, the significant FDG uptake at multiple anatomic sites is a strong indication of PMR [42,58]. In this regard, Slart et al confirmed that 18F-FDG PET-CT is highly effective to identify inflammation in large vessels, offering precise imaging that correlates well with clinical and histopathological findings [58]. Moreover, this imaging technique was also found to be very useful for detecting inflammation in characteristic areas such as the shoulders, hips, and ischial tuberosities.…”

Utility of multimodal molecular imaging in the diagnosis and decision-making in arterial diseases

“…18 F-FDG is the most studied PET/CT radiotracer for the diagnosis of LVV, with a sensitivity of 76 to 90% for GCA and 70-87% for TA [ 44 ]. The key imaging feature is the increased mural tracer uptake that can also help to distinguish between aortitis and periaortitis [ 45 ]. Additionally, 18 F-FDG uptake is an indicator of active disease, being a potential tool for follow-up ( Figure 3A - C )Blockmans et al .…”