Clinical value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography combined with computed tomography angiography in large-vessel vasculitis

Abstract

Abstract OBJECTIVES: The objectives of this study were to investigate the clinical application of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) combined with CT angiography (CTA) fusion images at diagnosis and assessment in large-vessel vasculitis (LVV). MATERIALS AND METHODS: Forty-six patients with LVV who underwent both 18F-FDG-PET/CT and CTA procedures were studied in the Second Hospital of Harbin Medical University from September 2019 to June 2022, and the clinical disease activity of patients was judged by the Physician Global Assessment. Clinical data, acute-phase reactants (APRs), and imaging data were collected. Meanwhile, the APRS must be obtained within 1 week of 18F-FDG-PET/CT. 18F-FDG-PET/CT was primarily used to evaluate LVV activity, while CTA was primarily used to observe morphological changes in arteries, including arterial wall thickening, narrowing, and corresponding complications. PET/CT images were evaluated by two nuclear medicine physicians, both of them unaware of the patients’ laboratory tests and clinical signs. Two nuclear medicine specialists evaluated the PET/CT images and PET/CTA images, who were blinded to the patients’ information. The concordance of two physicians in the LVV visual grading scale was studied by calculating the Cohen’s kappa index (k) which evaluates the power of concordance. The paired t-test was used to analyze the differences between PET/CTA images and PET/CT images. RESULTS: The sensitivity and specificity of the semi-quantitative analysis to assess LVV activity was 94.1% and 93.1%, respectively, when a cutoff of the mean SUVmax/SUVmeanliver of 1.15. It was found that the images obtained after delayed phase were clearer and the contrast between the arterial wall and the lumen was higher in 19 patients. We also concluded that PET/CTA examinations were able to detect more lesion sites compared to PET/CT examinations in 28 patients (P < 0.001), especially for patients with long-term treatment, and the interpretation of PET/CTA images took less time than PET/CT images(P < 0.001), ultimately achieving a shorter time, more comprehensive and accurate interpretation. CONCLUSION: Although 18F-FDG-PET/CT can assess the activity of LVV, it is poor at observing morphological changes in arteries. The use of 18F-FDG-PET/CTA imaging scans in LVV can accurately assess disease activity while at the same time providing a comprehensive, accurate, and efficient determination of disease severity, allowing patients to receive comprehensive diagnostic information from PET/CTA examination.