Development of a simple standardized scoring system for assessing large vessel vasculitis by 18F-FDG PET-CT and differentiation from atherosclerosis

European Journal of Nuclear Medicine and Molecular Imaging, vol. 50, pp. 2647–2655

Abstract

PURPOSE: This study is to develop a structured approach to distinguishing large-artery vasculitis from atherosclerosis using 18-fluorodeoxyglucose positron emission tomography combined with low-dose computed tomography (FDG PET/CT). METHODS: FDG PET/CT images of 60 patients were evaluated, 30 having biopsy-proven giant cell arteritis (GCA; the most common form of large-artery vasculitis), and 30 with severe atherosclerosis. Images were evaluated by 12 nuclear medicine physicians using 5 criteria: FDG uptake pattern (intensity, distribution, circularity), the degree of calcification, and co-localization of calcifications with FDG-uptake. Criteria that passed agreement, and reliability tests were subsequently analysed for accuracy using receiver operator curve (ROC) analyses. Criteria that showed discriminative ability were then combined in a multi-component scoring system. Both initial and final 'gestalt' conclusion were also reported by observers before and after detailed examination of the images. RESULTS: Agreement and reliability analyses disqualified 3 of the 5 criteria, leaving only FDG uptake intensity compared to liver uptake and arterial wall calcification for potential use in a scoring system. ROC analysis showed an area under the curve (AUC) of 0.90 (95%CI 0.87-0.92) for FDG uptake intensity. Degree of calcification showed poor discriminative ability on its own (AUC of 0.62; 95%CI 0.58-0.66). When combining presence of calcification with FDG uptake intensity into a 6-tiered scoring system, the AUC remained similar at 0.91 (95%CI 0.88-0.93). After exclusion of cases with arterial prostheses, the AUC increased to 0.93 (95%CI 0.91-0.95). The accuracy of the 'gestalt' conclusion was initially 89% (95%CI 86-91%) and increased to 93% (95%CI 91-95%) after detailed image examination. CONCLUSION: Standardised assessment of arterial wall FDG uptake intensity, preferably combined with assessment of arterial calcifications into a scoring method, enables accurate, but not perfect, distinction between large artery vasculitis and atherosclerosis.

Authors 9

1. Y. A. A. Bacour

   Amsterdam University Medical Centers

   Affiliation as printed

   Department of Internal Medicine, Amsterdam University Medical Center, Amsterdam 1007MB, PO Box 7057, Amsterdam, The Netherlands

   Department of Internal Medicine, Amsterdam University Medical Center, Amsterdam 1007MB, PO Box 7057, Amsterdam, The Netherlands

2. M. P. van Kanten

   Amsterdam University Medical Centers

   Affiliation as printed

   Department of Internal Medicine, Amsterdam University Medical Center, Amsterdam 1007MB, PO Box 7057, Amsterdam, The Netherlands

   Department of Internal Medicine, Amsterdam University Medical Center, Amsterdam 1007MB, PO Box 7057, Amsterdam, The Netherlands

3. Frits Smit Aachen Department of Radiology and Nuclear Medicine

   Alrijne Ziekenhuis

   Affiliation as printed

   Department of Radiology and Nuclear Medicine, Alrijne Hospital, Simon, Smitweg 1, 2353GA, Leiderdorp, The Netherlands

4. Emile F.I. Comans

   Amsterdam University Medical Centers

   Affiliation as printed

   Department of Radiology and Nuclear Medicine, Amsterdam University Medical Center, PO Box 7057, Amsterdam 1007MB, Amsterdam, The Netherlands

5. Mohammed Akarriou

   Spaarne Ziekenhuis

   Affiliation as printed

   Department of Radiology and Nuclear Medicine, Spaarne Hospital, PO Box 770, Hoofddorp, 2130AT, The Netherlands

6. Henrica C. W. de Vet

   Amsterdam Public Health · Amsterdam University Medical Centers · Vrije Universiteit Amsterdam · Amsterdam UMC Location Vrije Universiteit Amsterdam

   Affiliation as printed

   Department of Epidemiology and Data Science, Amsterdam Public Health Research Institute, Amsterdam University Medical Center, VrijeUniversiteit Amsterdam, Amsterdam 1007MB, PO Box 7057, Amsterdam, The Netherlands

7. Alexandre E. Voskuyl

   Amsterdam UMC Location Vrije Universiteit Amsterdam

   Affiliation as printed

   Amsterdam UMC-Location VUmc, Amsterdam Rheumatology and Immunology Center (ARC), Amsterdam 1007MB, PO Box 7057, Amsterdam, The Netherlands

8. Conny J. van der Laken

   Amsterdam UMC Location Vrije Universiteit Amsterdam

   Affiliation as printed

   Amsterdam UMC-Location VUmc, Amsterdam Rheumatology and Immunology Center (ARC), Amsterdam 1007MB, PO Box 7057, Amsterdam, The Netherlands

9. Yvo Michiel Smulders corresponding

   Amsterdam University Medical Centers

   Affiliation as printed

   Department of Internal Medicine, Amsterdam University Medical Center, Amsterdam 1007MB, PO Box 7057, Amsterdam, The Netherlands. y.smulders@amsterdamumc.nl

   Department of Internal Medicine, Amsterdam University Medical Center, Amsterdam 1007MB, PO Box 7057, Amsterdam, The Netherlands