Whole-Body [18F]FDG PET/CT Can Alter Diagnosis in Patients with Suspected Rheumatic Disease

Abstract

The 2-deoxy-d-[18F]fluoro-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) is widely utilized to assess the vascular and articular inflammatory burden of patients with a suspected diagnosis of rheumatic disease. We aimed to elucidate the impact of [18F]FDG PET/CT on change in initially suspected diagnosis in patients at the time of the scan. Thirty-four patients, who had undergone [18F]FDG PET/CT, were enrolled and the initially suspected diagnosis prior to [18F]FDG PET/CT was compared to the final diagnosis. In addition, a semi-quantitative analysis including vessel wall-to-liver (VLR) and joint-to-liver (JLR) ratios was also conducted. Prior to [18F]FDG PET/CT, 22/34 (64.7%) of patients did not have an established diagnosis, whereas in 7/34 (20.6%), polymyalgia rheumatica (PMR) was suspected, and in 5/34 (14.7%), giant cell arteritis (GCA) was suspected by the referring rheumatologists. After [18F]FDG PET/CT, the diagnosis was GCA in 19/34 (55.9%), combined GCA and PMR (GCA + PMR) in 9/34 (26.5%) and PMR in the remaining 6/34 (17.6%). As such, [18F]FDG PET/CT altered suspected diagnosis in 28/34 (82.4%), including in all unclear cases. VLR of patients whose final diagnosis was GCA tended to be significantly higher when compared to VLR in PMR (GCA, 1.01 ± 0.08 (95%CI, 0.95–1.1) vs. PMR, 0.92 ± 0.1 (95%CI, 0.85–0.99), p = 0.07), but not when compared to PMR + GCA (1.04 ± 0.14 (95%CI, 0.95–1.13), p = 1). JLR of individuals finally diagnosed with PMR (0.94 ± 0.16, (95%CI, 0.83–1.06)), however, was significantly increased relative to JLR in GCA (0.58 ± 0.04 (95%CI, 0.55–0.61)) and GCA + PMR (0.64 ± 0.09 (95%CI, 0.57–0.71); p < 0.0001, respectively). In individuals with a suspected diagnosis of rheumatic disease, an inflammatory-directed [18F]FDG PET/CT can alter diagnosis in the majority of the cases, particularly in subjects who were referred because of diagnostic uncertainty. Semi-quantitative assessment may be helpful in establishing a final diagnosis of PMR, supporting the notion that a quantitative whole-body read-out may be useful in unclear cases.

PET-Derived Increased Inflammation in Large Vessels is linked to Relapse-Free Survival in Patients with Giant Cell Arteritis

“…[ 18 F]FDG PET data was reconstructed following recommendations of the manufacturer. Further details can be found in 14 . Image analysis was performed according to the current guidelines 12 and performed by a first reader (MF, KVG) and confirmed by an expert reader (RAW) in inconclusive cases.…”

“…As such, from a cohort of 60 patients with GCA who underwent [ 18 F]FDG-PET/CT at initial diagnosis, 21 patients were retrospectively selected who were therapy-naïve at the time of imaging and were followed up for at least six months after imaging. Parts of this cohort have already been investigated in [14] and [15], but without assessing predictive performance of PET signal in treatment-naïve subjects. Clinical parameters and blood-based inflammatory biomarkers (C-reactive protein [CRP] and white blood cell count [WBC]) were collected at time of scan (i. e., prior to any treatment).…”

Could [18F]FDG PET/CT or PET/MRI Be Useful in Patients with Skull Base Osteomyelitis?

“…At first, this tracer was used mainly for the assessment of neoplastic diseases, given its ability to detect hypermetabolic lesions on the basis of their glycolytic metabolism [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. However, high glucose metabolism characterizes also activated inflammatory cells, and the use of [ 18 F]FDG PET has emerged for the evaluation of infectious and inflammatory diseases [ 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. In this setting, the role of [ 18 F]FDG PET imaging for the assessment of SBO is emerging.…”