In vivo molecular imaging of experimental joint inflammation by combined (18)F-FDG positron emission tomography and computed tomography.
BACKGROUND
The purpose of this work was to establish and validate combined small animal positron emission tomography - computed tomography (PET/CT) as a new in vivo imaging method for visualisation and quantification of joint inflammation.


METHODS
Signalling of radioisotope ¹⁸F labelled Fluorodeoxyglucose (¹⁸F-FDG) injected in mice with glucose-6-phosphate isomerase (G6PI)-induced arthritis was analysed by PET/CT. Accumulation of ¹⁸F-FDG in tissue was quantified by PET measurement, whereas high definition CT delivered anatomical information. The fusion of both images revealed in detail spatial and temporal distribution and metabolism of ¹⁸F-FDG.


RESULTS
A distinct ¹⁸F-FDG signal could be measured by PET in carpal and tarsal joints, from mice with early or established arthritis. In contrast, no accumulation of ¹⁸F-FDG was detectable before arthritis onset. Comparison of ¹⁸F-FDG joint uptake with histopathological evaluation revealed a significant correlation of both methods.


CONCLUSIONS
Small animal PET/CT using ¹⁸F-FDG is a feasible method for monitoring and, more importantly, quantitative assessment of inflammation in G6PI-arthritis. Since it is possible to perform repeated non-invasive measurements in vivo, not only numbers of animals in preclinical studies can markedly be reduced by this method, but also longitudinal studies come into reach, e. g. for individual flare-up reactions or monitoring therapy response in progressive arthritis.
Institute of Immunology, Jena University Hospital, Leutragraben 3, 07743 Jena, Germany.
Ingo M
IM
Irmler
Thomas
T
Opfermann
Peter
P
Gebhardt
Mieczyslaw
M
Gajda
Rolf
R
Bräuer
Hans P
HP
Saluz
Thomas
T
Kamradt
D000818:Animals; D001169:Arthritis, Experimental / Q000000981:diagnostic imaging*; D019788:Fluorodeoxyglucose F18; D051379:Mice; D008811:Mice, Inbred DBA; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed / Q000379:methods*
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18