Use of positron emission tomography (PET) for the diagnosis of large-vessel vasculitis

Clinical characterization of aortitis and periaortitis: study of 134 patients from a single university hospital

Aortitis and periaortitis refer to the inflammation of the aortic wall and the surrounding tissues. Both conditions are associated with various diseases and express nonspecific manifestations. Early diagnosis and treatment are crucial to improve the prognosis of the disease. This study aimed to assess the causes and main clinical features of aortitis and periaortitis in patients from a single centre in Spain. Observational, retrospective study of patients diagnosed with aortitis or periaortitis at a Spanish referral center over the last decade. 134 patients (87 female; mean age of 55.1 ± 9.1 years) were recruited, 132 of which had aortitis and two periaortitis. Aortitis was associated with giant cell arteritis (n = 102), Takayasu's arteritis (n = 6), IgG4-related disease (n = 6), infectious diseases (n = 3), malignancy (n = 1), drugs (n = 1), isolated aortitis (n = 1), and other immune-mediated inflammatory diseases (IMIDs) (n = 12). IMIDs included were Sjögren's syndrome (n = 2), sarcoidosis (n = 2), rheumatoid arthritis (n = 2), axial spondyloarthritis (n = 2), inflammatory bowel disease (n = 1), primary biliary cirrhosis (n = 1), idiopathic pulmonary fibrosis (n = 1), and polyarteritis nodosa (n = 1). Periaortitis was due to idiopathic retroperitoneal fibrosis in both cases. Imaging techniques used for diagnosis included 18F-FDG PET/CT scan (n = 133), CT-angiography (n = 44), and/or MRI-angiography (n = 33). Polymyalgia rheumatica (52.2%) and asthenia (53.7%) were the most common manifestations, followed by limb claudication (23.9%) and inflammatory back pain (26.9%). Acute-phase reactants were typically increased. Aortitis is a common condition and may be associated with multiple non-infectious diseases. Its clinical presentation is often unspecific, requiring a high level of suspicion to get an early diagnosis and treatment.

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

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.