Diagnostic accuracy of positron emission tomography for assessment of disease activity in large vessel vasculitis

The Italian Society of Rheumatology clinical practice guidelines for the management of large vessel vasculitis

Objective: Since of the last publication of last recommendations on primary large-vessel vasculitis (LVV) endorsed by the Italian Society of Rheumatology (SIR) in 2012, new evidence emerged regarding the diagnosis and the treatment with conventional and biologic immunosuppressive drugs. The associated potential change of clinical care supported the need to update the original recommendations. Methods: Using the grading of recommendations assessment, development and evaluation (GRADE)-ADOLOPMENT framework, a systematic literature review was performed to update the evidence supporting the European Alliance of Associations for Rheumatology (EULAR) guidelines on LVV as reference. A multidisciplinary panel of 12 expert clinicians, a trained nurse, and a patients’ representative discussed the recommendation in cooperation with an Evidence Review Team. Sixty-one stakeholders were consulted to externally review and rate the recommendations. Results: Twelve recommendations were formulated. A suspected diagnosis of LVV should be confirmed by imaging or histology. In active GCA or TAK, the prompt commencement of high dose of oral glucocorticoids (40-60 mg prednisone-equivalent per day) is strongly recommended to induce clinical remission. In selected patients with GCA (e.g., refractory or relapsing disease or patients at risk of glucocorticoid related adverse effects) the use of an adjunctive therapy (tocilizumab or methotrexate) is recommended. In all patients diagnosed with TAK, adjunctive therapies, such as conventional synthetic or biological immunosuppressants, should be given in combination with glucocorticoids. Conclusions: The new set of SIR recommendations was formulated in order to provide a guidance on both diagnosis and treatment of patients suspected of or with a definite diagnosis of LVV.

18F-FDG PET/CT in Late Acquisition Identifies Sites of Active Disease in Treated Takayasu Arteritis

OBJECTIVE

Few studies have taken advantage of 18F-fluorodeoxyglucose positron emission tomography associated with computed tomography (18F-FDG PET/CT) to personalize patient evaluation and identify sites of more active disease in Takayasu arteritis (TA)-treated patients. This study aimed to evaluate the utility of 18F-FDG PET/CT in late acquisition in identifying sites of active disease in patients under full treatment for TA.

METHODS

In this cross-sectional study, patients under full treatment underwent whole-body 18F-FDG PET/CT. Sites of increased 18F-FDG uptake were classified by a score of 3 on the visual scale using the liver uptake as reference. A quantitative analysis was also performed by measuring the maximum standardized uptake value (SUV) of the vascular wall of affected arteries. Disease activity using the National Institutes of Health criteria was also evaluated.

RESULTS

Of the 20 patients, there were 18 female and 2 male patients, with a mean age of 43.6 (±11.58) years and a disease duration of 8.3 (±6.25) years. Thirteen participants (65%) were in inflammatory activity according to the criteria proposed by the National Institutes of Health. All patients received immunosuppressive agents, and one of them received immunobiological treatment. The highest SUV value was 6.2 in the aortic arch, and the lowest was 1.0 in the subclavian artery. The mean maximum SUV did not differ between clinically active and inactive patients. In the visual analysis, all participants had at least 1 vascular site with inflammatory activity, with an uptake ≥2 in relation to the liver. The aortic arch was the most frequently involved site.

CONCLUSIONS

This study showed that 18F-FDG PET/CT in late acquisition is an effective imaging method to assess TA activity even in fully treated patients.

Current advances in giant cell arteritis

PURPOSE OF REVIEW

The aim of this study was to present the latest advances in giant cell arteritis (GCA) care, and recent national and international rheumatology societies guidance which influences clinical practice.

RECENT FINDINGS

Cranial ultrasound reduces diagnostic delay and improves clinical outcomes. Immediate high dose glucocorticoids remain the standard treatment for GCA. Controlled trial evidence using Tocilizumab, an interleukin-6 receptor antagonist, shows good clinical efficacy with steroid-sparing effects.

SUMMARY

Improved patient outcomes require formalizing pathways to diagnosis and closer liaison with rheumatology for long-term management with second-line therapies.

A novel model to assess disease activity in Takayasu arteritis based on 18F-FDG-PET/CT: a Chinese cohort study

OBJECTIVE

To investigate the utility of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) in assessing disease activity in Takayasu arteritis (TA).

METHODS

Ninety-one patients with TA, were recruited from a Chinese cohort. Clinical data, acute-phase reactants (APRs), and 18F-FDG-PET/CT findings were simultaneously recorded. The value of using 18F-FDG-PET/CT to identify active disease was evaluated, using erythrocyte sedimentation rate (ESR) as a reference. Disease activity assessment models were constructed and concordance index (C-index), net reclassification index (NRI), and integrated discrimination index (IDI) were evaluated to compare the benefits of the new modes with ESR and Kerr score.

RESULTS

In total, 64 (70.3%) cases showed active disease. Higher levels of ESR and CRP, and lower interleukin (IL)-2R levels, were observed in active cases. 18F-FDG-PET/CT parameters, including SUVmean, SUVratio1, SUVratio2, sum of SUVmean, and sum of SUVmax, were significantly higher in active disease groups. The C index threshold of ESR to indicate active disease was 0.78 (95% CI: 0.69-0.88). The new activity assessment model combining ESR, sum of SUVmean, and IL-2R showed significant improvement in C index over the ESR method (0.96 vs 0.78, p < 0.01; NRI 1.63, p < 0.01; and IDI 0.48, p < 0.01). The new model also demonstrated modest superiority to Kerr score assessment (0.96 vs 0.87, p = 0.03; NRI 1.19, p < 0.01; and IDI 0.33 p < 0.01).

CONCLUSIONS

A novel 18F-FDG-PET/CT-based method that involves combining the sum of SUVmean with ESR score and IL-2R levels demonstrated superiority in identifying active TA compared with conventional methods.

Diagnostic value of [18F]FDG-PET/CT for treatment monitoring in large vessel vasculitis: a systematic review and meta-analysis

PURPOSE

Monitoring disease activity in patients with large vessel vasculitis (LVV) can be challenging. [18F]FDG-PET/CT is increasingly used to evaluate treatment response in LVV. In this systematic review and meta-analysis, we aimed to summarize the current evidence on the value of [18F]FDG-PET/CT for treatment monitoring in LVV.

METHODS

PubMed/MEDLINE and the Cochrane library database were searched from inception through October 21, 2020. Studies containing patients with LVV (i.e. giant cell arteritis, Takayasu arteritis and isolated aortitis) that received treatment and underwent [18F]FDG-PET/CT were included. Screening, full-text review and data extraction were performed by 2 investigators. The risk of bias was examined with the QUADAS-2 tool. Meta-analysis of proportions and diagnostic test accuracy was performed by a random-effects model and bivariate model, respectively.

RESULTS

Twenty-one studies were included in the systematic review, of which 8 studies were eligible for meta-analysis. Arterial [18F]FDG uptake decreased upon clinical remission in longitudinal studies. High heterogeneity (I² statistic 94%) precluded meta-analysis of the proportion of patients in which the scan normalized during clinical remission. Meta-analysis of cross-sectional studies indicated that [18F]FDG-PET/CT may detect relapsing/refractory disease with a sensitivity of 77% (95%CI 57-90%) and specificity of 71% (95%CI 47-87%). Substantial heterogeneity was observed among the cross-sectional studies. Both variation in clinical aspects and imaging procedures contributed to the heterogeneity.

CONCLUSION

Treatment of LVV leads to reduction of arterial [18F]FDG uptake during clinical remission. [18F]FDG-PET/CT has moderate diagnostic accuracy for detecting active LVV. [18F]FDG-PET/CT may aid treatment monitoring in LVV, but its findings should be interpreted in the context of the clinical suspicion of disease activity. This study underlines the relevance of published procedural recommendations for the use of [18F]FDG-PET/CT in LVV.

The importance of FDG PET/CT in the diagnostic process of the middle aortic syndrome in a 15-year-old boy patient with suspected systemic vasculitis and final diagnosis of Williams-Beuren syndrome

The differential diagnosis in children with the systemic vasculopathy is still a challenge for clinicians. The progress in vascular imaging and the latest recommendations improve the diagnostic process, but only single reports describe the use of new imaging tests in children. The publication aims to demonstrate the important role of 18F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography combined with anatomical computed tomography angiography (PET/CTA) imaging in the case of a 15-year-old boy with chest pain, intermittent claudication, hypertension and features of middle aortic syndrome in computed tomography angiography (CTA). The patient was suspected to have Takayasu arteritis, but was finally diagnosed with Williams–Beuren syndrome. The case indicates that the FDG PET/CT imaging might be essential in the diagnostic process of middle aortic syndrome in children. We suggest that this imaging technique should be considered in the diagnostic process of systemic vasculopathy particularly in children.