18F-FDG PET/CT plays a unique role in the management of Takayasu arteritis patients with atypical manifestations

Abstract

Objective The present study aimed to evaluate the value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) aiding in diagnosing and evaluating disease activity in Takayasu arteritis (TA) patients with atypical clinical manifestations. Methods A retrospective study of 22 TA patients was conducted. All the participants were classified into two groups. Group one including 12 patients, who did not fulfill American College of Rheumatology (ACR) criteria, were diagnosed by modified Ishikawa criteria. Group two involving ten patients, who did not satisfy the modified Ishikawa criteria or ACR criteria, were clinically diagnosed as TA after panel discussion by a combination of clinical data, excluding other diagnoses. PET/CT results were analyzed using quantitative and qualitative metrics. Disease activity was evaluated using the US National Institutes of Health (NIH) criteria. Results In group one, nine patients in active stage and two patients in inactive stage had active FDG uptake. One patient in inactive stage had inactive PET/CT results. In group two, five patients in active stage had active FDG uptake and five patients in inactive stage had inactive FDG uptake with SUVmax values of several vascular lesions slightly lower than livermean in each person. The sensitivity of PET/CT scans for evaluating disease activity was 100.0%, specificity was 75.0%, positive predictive value was 87.5%, and negative predictive value was 100.0% compared to NIH criteria. Conclusions PET/CT plays a unique role in diagnosing these TA with atypical manifestation and assisting in evaluating disease activity. Key Points • Diagnosis of these TA patients with atypical manifestations may be difficult. • PET/CT plays a unique role in diagnosing these TA patients and assisting in evaluating disease activity.