WITHDRAWN: A re-evaluation of 18F-FDG PET/CT for diagnosing relapsing polychondritis and monitoring the therapeutic response to treatment

Abstract

Background: Relapsing polychondritis (RP) is a rare degenerative disease and its diagnosis is often delayed and difficult. Although the use of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (18 F-FDG PET/CT) for diagnosing RP has been reported previously, its true diagnostic value is uncertain due to the limited number of published case reports. Moreover, its value for biopsy guidance and therapeutic response monitoring remain controversial. Materials and Methods: Data on 30 patients with a clinical diagnosis of RP who underwent PET/CT scans were retrospectively reviewed. Follow-up scans were performed in 10 patients, and visual scores (VS) and maximal standard uptake (SUV max) values were analysed. Results: With the initial scan, 83.3% of patients showed lesions in more than one cartilage. Mean VS and SUV max values in the cartilages were 2.92 ± 0.38 and 4.06 ± 0.18, respectively. In 18 patients with no history of corticosteroid treatment, more cartilages were affected than in patients who previously received corticosteroids (3.89 ± 0.29 vs 2.75 ± 0.63, respectively; p = 0.07). Positive rates for PET/CT-guided biopsy in nasal, auricular and tracheal/bronchial cartilages were 100%, 88.9% and 10.5%, respectively. In comparison, the positive rate for non-PET/CT-guided biopsy of auricular cartilage was 92.3%. Compared with the initial scan, the second scan had significantly lower mean VS (1.41 ± 0.20 vs 2.92 ± 0.38, respectively; p < 0.0001) and SUVmax values (2.76 ± 0.14 vs 4.06 ± 0.18, respectively; p < 0.001). Conclusions: FDG uptake in multiple cartilages suggests a diagnosis of RP, but repeated administration of corticosteroids may undermine the diagnostic value of 18 F-FDG PET/CT. Further investigation of its use in locating biopsy sites and in monitoring the response to treatment is required.