Diagnostics (Nov 2021)

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

  • Matthias Fröhlich,
  • Sebastian Serfling,
  • Takahiro Higuchi,
  • Martin G. Pomper,
  • Steven P. Rowe,
  • Marc Schmalzing,
  • Hans-Peter Tony,
  • Michael Gernert,
  • Patrick-Pascal Strunz,
  • Jan Portegys,
  • Eva-Christina Schwaneck,
  • Ottar Gadeholt,
  • Alexander Weich,
  • Andreas K. Buck,
  • Thorsten A. Bley,
  • Konstanze V. Guggenberger,
  • Rudolf A. Werner

DOI
https://doi.org/10.3390/diagnostics11112073
Journal volume & issue
Vol. 11, no. 11
p. 2073

Abstract

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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 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.

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