s36_ab3

Additional value of positron emission tomography in diagnosis and follow-up of patients with large vessel vasculitides

K. de Leeuw¹ , M. Bijl¹ , P.L. Jager²

Department of Clinical Immunology, ²Department of Nuclear Medicine and PET center, University Hospital, Groningen, The Netherlands.

ABSTRACT
Objectives
To determine the value of Positron Emission Tomography (PET) in the diagnosis of Takayasu arteritis (TA) and giant cell arteritis (GCA) and its value in the assessment of disease activity and response to therapy.

Methods
In 5 consecutive patients diagnosed with TA or GCA, PET using the tracer F18-deoxyglucose (FDG) was performed when disease activity was suspected based on clinical and laboratory parameters. PET was repeated after therapeutic intervention when disease remission was achieved. PET findings were compared with an-giography, MRA and clinical parameters.

Results
PET visualised inflamed ar-teries in all 5 patients, but there was a discrepancy between PET and angiog-raphy or MRA. In 8 arteries of 4 patients only PET showed disease involve-ment, while in 5 arteries of 2 patients only angiography or MRA showed in-volvement. After treatment and the disappearance of clinical symptoms, FDG uptake was clearly reduced compared to the initial scan in all patients. In all but one the acute phase response declined. In that patient a urinary tract infection explained the elevated acute phase response, as this normalised after antibiotic treatment.

Conclusion
PET is a promising new technique for the diagnosis of large vessel vasculitides. Furthermore, PET appears to be a valuable tool for the as-sessment of disease activity during follow-up and of the response to therapy.

Key words
Large vessel vasculitides, follow-up, response to therapy, positron emission tomography.

Please address correspondence to: Marc Bijl, MD, PhD, Department of Internal Medicine, Division of Clinical Immunology, University Hospital, PO Box 30.001, 9700 RB Groningen, The Netherlands.
E-mail: m.bijl@int.azg.nl.