FDG Uptake in Large-Vessel Giant Cell Arteritis After Short-term, High-Dose Steroid Treatment

Giant Cell Arteritis Clinical Trial

Official title: Fluorine-18-fluorodeoxyglucose Uptake in Large-Vessel Giant Cell Arteritis After Short-term, High-Dose Steroid Treatment - A Diagnostic Window of Opportunity?

Status Completed

Clinical Trial Summary

Giant cell arteritis (GCA) affects large and medium sized vessels. Large vessel-GCA (LV-GCA) affecting aorta and/or its main branches is seen a) together with temporal arteritis (AT-GCA), b) as isolated LV-GCA but also c) with polymyalgia rheumatica.

There is a risk of vision loss and cerebral thromboembolic events or great vessel injury in GCA. With delayed or inadequate treatment mortality and morbidity increases. This highlights the need of fast diagnosis and early treatment.

The cornerstone in the diagnosis of GCA is a positive temporal artery biopsy. Patients with LV-GCA have more general, but less cephalic symptoms than patients with AT-GCA. Also, biopsy from large vessels can rarely be done and only 50% have a positive temporal artery biopsy (TAB). Hence, diagnosis often rely on imaging.

Fluorine-18-fluorodeoxyglucose positron-emission tomography (FDG PET)/CT has shown high diagnostic sensitivity and specificity and is believed to be superior to other imaging modalities in the diagnosis of LV-GCA . The impact of FDG PET/CT in the management of LV-GCA has been evaluated and has shown to increase the diagnostic accuracy in a significant proportion of patients. However, studies have indicated a lower sensitivity in steroid treated patients.

The aim of this study, was to evaluate the effect of steroid treatment on large-vessel FDG uptake in new-onset, treatment-naive LV-GCA by repetitive FDG PET/CT pre- and post therapeutic. With insights into the diagnostic capabilities after treatment is initiated, the possibility of timely treatment and confident diagnostic work up will improve.

Clinical Trial Description

As standard of care, patients suspected of GCA undergo clinical examination, laboratory screening, temporal artery biopsy, vascular ultrasound examination and FDG PET/CT.

All patients with a diagnosis of GCA will be treated with 60 mg af prednisolone and tapered according to a predefined algorithm.

In patients with FDG PET/CT verified LV-GCA, FDG PET/CT is repeated after either 3 (n=12) or 10 (n=12) days of steroid treatment.

An experienced nuclear medicine physician (LCG), blinded to clinical symptoms and findings, qualitatively assesses PET scans. A semiquantitative approach is applied (a.m. Meller) in which FDG uptake in vascular regions is graded on a 5-point scale (0 = no uptake, 1 = uptake below or equal to blood pool, 2 = above blood pool but below liver, 3 = above liver, 4 = 2 times above liver). Any score ≥3 is considered consistent with vasculitis. Sensitivity of post-therapeutic FDG PET/CT will be evaluated.

Moreover, standard uptake values (SUV) mean and maximum values in vascular regions will be calculated. A ratio SUV(wall)/SUV(blood pool) and a total metabolic burden (TMB) based on affected vascular volume and SUV mean values are obtained as measures of vascular wall inflammation. ;

Related Conditions & MeSH terms

• Arteritis
• Giant Cell Arteritis
• Polymyalgia Rheumatica

• NCT number: NCT03285945
• Study type: Observational
• Source: University of Aarhus
• Status: Completed
• Phase: N/A
• Start date: October 2014
• Completion date: September 2016