MRI and FDG-PET in the assessment of inflammatory aortic arch syndrome in complicated courses of giant cell arteritis

Beyond the symptoms: Personalizing giant cell arteritis care through multidimensional patient reported outcome measure

BACKGROUND

Giant Cell Arteritis (GCA) is the commonest form of systemic vasculitis in people over the age of 50. Published research highlighted the lack of a disease-specific patient reported outcomes (PROMs) for GCA.

OBJECTIVES

To assess the validity, reliability and responsiveness to change of a devised disease specific patient self-reported outcome measures questionnaire for Giant Cell Arteritis (GCA).

METHODS

The GCA-PROMs was conceptualized based on frameworks outlined in the OMERACT developed core set of Outcome Measures for Large-Vessel Vasculitis and the guiding principles of the FDA guidance. Initially, cognitive interviews were conducted to identify item pool of questions. Item selection and reduction was achieved based on patients as well as an interdisciplinary group of specialists. Rasch and internal consistency reliability analyses were implemented.

RESULTS

A total of 54 GCA patients completed the questionnaire. The GCA-PROMs questionnaire was reliable as demonstrated by a high standardized alpha (0.878-0.983). Content construct assessment of the GCA-PROMs functional disability and QoL revealed significant correlation (p< 0.01) with both HAQ and EQ-5D. Changes in functional disability, QoL showed significant (p< 0.01) variation with diseases activity status in response to therapy.

CONCLUSIONS

The developed GCA-PROMs questionnaire is a reliable and valid instrument for assessment of GCA patients. A stratified treatment regimen depending on the individual patient's risk factors as well as preferences and associated comorbidities is the best approach to tailored patient management.

18-Fluorodeoxyglucose positron emission tomography/computed tomography for large vessel vasculitis in clinical practice

Diagnosis, prognostic assessment, and monitoring disease activity in patients with large vessel vasculitis (LVV) can be challenging. Early recognition of LVV and treatment adaptation is essential because vascular complications (aneurysm, dilatations, ischemic complications) or treatment related side effects can occur frequently in these patients. 18-fluorodeoxyglucose positron emission tomography/computed tomography (2-[18F]FDG-PET/CT) is increasingly used to diagnose, follow, and evaluate treatment response in LVV. In this review, we aimed to summarize the current evidence on the value of 2-[18F]FDG-PET/CT for diagnosis, follow, and treatment monitoring in LVV.

Magnetic resonance imaging-based diagnosis of aortitis preceding development of a thoracic aneurysm in a patient with giant cell arteritis: a case report

Background

Inflammatory manifestation in the aortic arch can be a complication of giant cell arteritis (GCA), potentially requiring surgical therapy in the case of aneurysmatic dilatation.

Case summary

We report the case of a 73-year-old female patient with GCA in whom a typical appearance of arteritis was visualized on magnetic resonance imaging of the superficial temporal arteries. Additionally, ectasia (4.7 cm) of the ascending aorta with a mural rim of increased contrast media uptake was detected at the time of the initial diagnosis, which is an indicator of aortitis. While the diameter had only minimally increased in a computed tomography angiography (CTA) examination after 8 months, a subsequent CTA revealed an increased diameter of 5.8 cm and maximum at the level of the ascending aorta another 22 months later, indicating urgent surgery to replace the ascending aorta.

Discussion

Magnetic resonance imaging can detect silent, generalized manifestations of GCA such as severe aortitis, which may possibly lead to aneurysmatic dilatation, urging closer follow-up imaging. Detection of the ongoing process and subsequent follow-up imaging protects patients by avoiding rupture.

Imaging features of 18F-FDG PET/CT in different types of systemic vasculitis

OBJECTIVE

To analyze ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) image features in different types of systemic vasculitis and explore its classification and diagnostic significance for systemic vasculitis.

METHODS

Clinical and ¹⁸F-FDG PET/CT imaging data of 71 consecutive patients (34 males, 37 females, mean age 53.4 ± 20.5 years) who were examined at Peking University People's Hospital and diagnosed with active systemic vasculitis were analyzed retrospectively, and ¹⁸F-FDG PET/CT imaging features of different types of systemic vasculitis were analyzed in patients with positive ¹⁸F-FDG PET/CT findings.

RESULTS

The proportions of large-, medium-, small-, and variable-vessel vasculitis were 36.6%, 15.5%, 29.6%, and 18.3%, respectively, and 93.0% of patients had positive findings on PET/CT, of which 63.6% had vascular involvement and 53.0% had extravascular involvement. Different types of vasculitis had different lesion sites, distribution patterns, and morphological changes. Large-vessel vasculitis mainly affected the aorta and its branches to the head and neck. Takayasu arteritis showed segmental involvement of the vascular and morphological changes of the vessel wall. Giant cell arteritis manifested as diffuse vascular involvement, which usually involved the temporal artery and the abdominal aorta and its branches. Medium-vessel vasculitis polyarteritis nodosa manifested as diffuse vascular involvement of both lower extremities. Small-vessel vasculitis anti-neutrophil cytoplasmic antibody-associated vasculitis manifested as granulomatous inflammation of extravascular regions. Variable-vessel vasculitis Behcet's disease involved both blood vessels and extravascular regions.

CONCLUSION

Different types of systemic vasculitis show characteristic manifestations in ¹⁸F-FDG PET/CT images, which may be useful for the diagnosis and classification of systemic vasculitis.

KEY POINTS

• Determining an early diagnosis of systemic vasculitis may be challenging. • Different types of systemic vasculitis show characteristic manifestations in ¹⁸F-FDG PET/CT images. • ¹⁸F-FDG PET/CT may be useful for the diagnosis and classification of systemic vasculitis.

Diagnostic utility of serum biomarkers in large vessel vasculitis and their correlation with positron emission tomography

OBJECTIVES

To investigate the association between vascular inflammation, as detected by positron emission tomography (PET) imaging and interleukin-6 (IL-6), pentraxin3, and B-cell-activating factor (BAFF) in subjects with LVV.

METHODS

The study included newly diagnosed giant cell arteritis (GCA, n = 27) or Takayasu arteritis (n = 9) patients and healthy control (HC, n = 31) subjects. PET scan and blood samples were obtained before the introduction of treatments. IL-6, PTX3, and BAFF levels were determined quantitatively by enzyme-linked immunosorbent assay kits.

RESULTS

Thirty-six patients with LVV (20 females, 16 males; age 64.5 ± 16.6 years) and 31 HC (14 females, 17 males; age 37.1 ± 9.6 years) were included. Serum levels of IL-6, PTX3, and BAFF were increased in patients with newly diagnosed LVV compared with healthy control subjects. In receiver operating characteristics (ROC) analysis, serum IL-6 and BAFF provided excellent discrimination of newly diagnosed LVV patients from HC (area under the ROC curve of >0.90 and >0.80, respectively). None of the inflammatory markers correlated with vascular inflammatory activity determined by PET scanning.

CONCLUSIONS

Our results suggest that IL-6 and BAFF may serve as markers of large vessel vasculitis, while PTX3 is not useful. None of the inflammatory markers correlated with PET assessed vasculitis activity.

Comparing Semi-quantitative and Qualitative Methods of Vascular FDG-PET Activity Measurement in Large-Vessel Vasculitis

The study rationale was to assess the performance of qualitative and semi-quantitative scoring methods for ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) assessment in large-vessel vasculitis (LVV). Methods: Patients with giant cell arteritis (GCA) or Takayasu's arteritis (TAK) underwent clinical and imaging assessment, blinded to each other, within a prospective observational cohort. FDG-PET-CT scans were interpreted for active vasculitis by central reader assessment. Arterial FDG uptake was scored by qualitative visual assessment using the PET vascular activity score (PETVAS) and by semi-quantitative assessment using standardized uptake values (SUV) and target-to-background ratios (TBR) relative to liver/blood activity. Performance of each scoring method was assessed by intra-rater reliability using the intra-class coefficient (ICC) and area under receiver-operator characteristic curves (AUC), using physician assessment of clinical disease activity and reader interpretation of vascular PET activity as independent reference standards. Wilcoxon signed-rank test was used to analyze change in arterial FDG uptake over time. Results: Ninety-five patients (GCA=52; TAK=43) contributed 212 FDG-PET studies. The ICC for semi-quantitative evaluation [0.99 (range 0.98-1.00)] was greater than the ICC for qualitative evaluation [0.82 (range 0.56-0.93)]. PETVAS and TBR metrics were more strongly associated with reader interpretation of PET activity than SUV metrics. All assessment methods were significantly associated with physician assessment of clinical disease activity, but the semi-quantitative metric TBRLiver¬ achieved the highest AUC (0.66). Significant but weak correlations with C-reactive protein were observed for SUV metrics (r = 0.19, p<0.01) and TBRLiver (r = 0.20, p<0.01) but not for PETVAS. In response to increased treatment in 56 patients, arterial FDG uptake was significantly reduced when measured by semi-quantitative (TBRLiver 1.31 to 1.23, 6.1% ∆, p<0.0001) or qualitative (PETVAS 22 to 18, p<0.0001) methods. Semi-quantitative metrics provided complementary information to qualitative evaluation in cases of severe vascular inflammation. Conclusion: Both qualitative and semi-quantitative methods to measure arterial FDG uptake are useful to assess and monitor vascular inflammation in LVV. Compared to qualitative metrics, semi-quantitative methods have superior reliability and better discriminate treatment response in cases of severe inflammation.

Giant Cell Arteritis: A Systematic Review and Meta-Analysis of Test Accuracy and Benefits and Harms of Common Treatments

This systematic review compares treatment options for patients with giant cell arteritis (GCA) and evaluates the test accuracy of studies used in diagnosing and monitoring GCA. These studies were used to inform evidence-based recommendations for the American College of Rheumatology (ACR)/Vasculitis Foundation (VF) vasculitis management guidelines. A systematic review and search of articles in English in Ovid Medline, PubMed, Embase, and the Cochrane Library was conducted. Articles were screened for suitability, and studies presenting the highest level of evidence were given preference. Three hundred ninety-nine full-text articles addressing GCA questions were reviewed to inform 27 Population, Intervention, Comparison, and Outcome questions. No benefit was found with intravenous glucocorticoids (GCs) compared with high-dose oral GCs in patients with cranial ischemic symptoms (27.4% vs 12.3%; odds ratio [OR] 2.39 [95% confidence interval (CI) 0.75-7.62], [very low certainty of evidence]). Weekly tocilizumab with a 26-week GC taper was superior to a 52-week GC taper in patients achieving remission (risk ratio 4.00 [95% CI 1.97-8.12], [low certainty of evidence]). Non-GC immunosuppressive therapies with GCs compared with GCs alone showed no statistically significant in relapse at 1 year (OR 0.87 [95% CI 0.73-1.04], [moderate certainty of evidence]) or serious adverse events (OR 0.81 [95% CI 0.54-1.20]; [moderate certainty of evidence]). Temporal artery biopsy has a sensitivity of 61% (95% CI 38%-79%) and a specificity of 98% (95% CI 95%-99%) in patients with a clinical diagnosis of suspected GCA. This comprehensive systematic review synthesizes and evaluates the benefits and harms of different treatment options and the accuracy of commonly used tests for the diagnosis and monitoring of GCA.

Cardiac imaging of a patient with unusual presentation of granulomatosis with polyangiitis: A case report and review of the literature

BACKGROUND

Recent evidence suggests that cardiac involvement in patients with granulomatosis with polyangiitis (GPA) occurs more frequently than previously reported. Multimodality cardiac imaging is gaining attention in the diagnosis, prognostication, and follow-up of such patients; however, the data remain scarce.

RESULTS

2D-TTE was useful for initial screening; while both cardiac magnetic resonance imaging and 18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography (18FDG-PET/CT) metabolic imaging with rubidium-82 PET perfusion imaging were useful for characterization of myocardial disease. 18FDG-PET/CT was very useful for the follow-up of cardiac disease activity following treatment.

CONCLUSION

18FDG-PET/CT is sensitive for the detection of cardiac involvement by GPA and is useful for the tissue characterization and follow-up of disease activity following treatment.

[Long-term complications, monitoring and interventional treatment of large vessel vasculitis]

Giant cell arteritis (GCA) and Takayasu's arteritis (TAK) both belong to the group of large vessel vasculitides and require long-term drug treatment. Glucocorticoids (GC) are the first choice for the treatment of both diseases. For GCA immunosuppressants, such as tocilizumab or methotrexate should be considered in cases of treatment refractory and relapses or if there is a high risk for GC-related adverse events. In TAK patients the use of immunosuppressive agents should be considered for all patients. In the course of the disease, severe disease-associated and treatment-associated complications can occur. The most frequent disease-associated complications include visual impairment up to blindness in GCA, as well as vascular stenoses with ischemia and aortic aneurysms with possible dissection in GCA and TAK. Percutaneous transluminal angioplasty (PTA) and stenting are minimally invasive, low-risk interventional procedures for GCA and TAK patients with clinically significant vascular stenoses, despite a tendency to restenosis. Interventional procedures should be weighed up against vascular surgical approaches depending on the localization and the total clinical situation. All interventions should be conducted in a phase of stable remission when possible. For monitoring of disease activity in patients with GCA and TAK, assessment of clinical manifestations as well as C‑reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) are useful; however, both are unreliable under interleukin‑6 block with tocilizumab. The value of new biomarkers independent from interleukin‑6 and the importance of imaging (sonography, magnetic resonance angiography, computed tomography and positron emission tomography-CT) for monitoring GCA and TAK still have to be investigated in future studies.

[The current place of non-invasive large-vessel imaging in the diagnosis and follow-up of giant cell arteritis]

Large vessel involvement in giant cell arteritis has long been described, although its right frequency and potential prognostic value have only been highlighted for two decades. Large vessel involvement not only is associated with a high incidence of late aortic aneurysms, but also might cause greater resistance to glucocorticoids and longer treatment duration, as well as worse late cardiovascular outcomes. These data were brought to our attention, thanks to substantial progress recently made in large vessel imaging. This relies on four single, often complementary, approaches of varying availability: colour Doppler ultrasound, contrast-enhanced computed tomography with angiography and, magnetic resonance imaging, which all demonstrate homogeneous circumferential wall thickening and describe structural changes; 18F-fluorodeoxyglucose positron emission tomography-computed tomography (PET/CT), which depicts wall inflammation and assesses many vascular territories in the same examination. In addition, integrated head-and-neck PET/CT can accurately and reliably diagnose cranial arteritis. All four procedures exhibit high diagnostic performance for a large vessel arteritis diagnosis so that the choice is left to the physician, depending on local practices and accessibility; the most important is to carry out the chosen modality without delay to avoid false or equivocal results, due to early vascular oedema changes as a result of high dose glucocorticoid treatment. Yet, ultrasound study of the superficial cranial and subclavian/axillary arteries remains a first line assessment aimed at strengthening and expediting the clinical diagnosis as well as raising suspicion of large-vessel involvement. In treated patients, vascular imaging results are poorly correlated with clinical-biological controlled disease so that it is strongly recommended not to renew imaging studies unless a large vessel relapse or complication is suspected. On the other hand, a structural monitoring of aorta following giant cell arteritis is mandatory, but uncertainties remain regarding the best procedural approach, timing of first control and spacing between controls. Individuals at greater risk of developing aortic complication, e.g. those with classic risk factors for aneurysm and/or visualised aortitis, should be monitored more closely.

Etiology, Diagnosis and Management of Aortitis

Aortitis includes conditions with infectious or non-infectious etiology, characterized by inflammatory changes in one or more layers in aortic wall. Age at onset, geographic predilections, distribution and pattern of involvement in aorta, its branches and pulmonary arteries, and systemic associations provide a clue to etiology. Clinical presentations are often non-specific. An integrated approach including clinical, laboratory and imaging assessment is essential to confirm diagnosis and plan treatment. Assessment of disease activity is the key as it influences timing and outcome of treatment. Markers of activity include clinical, laboratory and imaging. Medical management remains the first-line therapy. Revascularization is indicated in the presence of hemodynamically significant stenosis and inactive disease. In the presence of flash pulmonary edema, left ventricular dysfunction or hypertensive encephalopathy, revascularization is performed irrespective of disease activity. Endovascular management is favored over surgery due to its high success and low restenosis rates. Symptomatic aneurysmal disease is usually managed by surgery.

Diagnosis of giant cell arteritis

GCA is the most common form of primary systemic vasculitis affecting older people. It is considered a clinical emergency because it can lead to irreversible blindness in around 20% of untreated cases. High doses of glucocorticoids should be initiated promptly to prevent disease-related complications; however, glucocorticoids therapy usually results in significant toxicity. Therefore, correct diagnosis is crucial. For many years, temporal artery biopsy has been considered the diagnostic ‘gold standard’ for GCA, but it has many limitations (including low sensitivity). US has proven to be effective for diagnosing GCA and can reliably replace temporal artery biopsy in particular clinical settings. In cases of suspected GCA with large-vessel involvement, other imaging modalities can be used for diagnosis (e.g. CT and PET). Here we review the current evidence for each diagnostic modality and propose an algorithm to diagnose cranial-GCA in a setting with rapid access to high quality US.

Fully integrated 18F-FDG PET/MR in large vessel vasculitis

BACKGROUND

To evaluate the usefulness of [18F] fluorodeoxyglucose (FDG) positron emission tomography (PET)/magnetic resonance (MR) in large vessels vasculitis (LVV) patients.

METHODS

We performed an observational retrospective study based on our records. Images were acquired on a PET/MR scanner using 18F-FDG-PET whole body imaging. For each PET scan, a qualitative analysis and a semi-quantitative measure using the maximum of the standardized uptake value (SUVMax) were performed. SUVMax measurements normalized to the liver uptake were categorized using a grading scale. Vessel's wall thickness (WT) was measured at five fixed points (inferior margin of T5, T9, T12, L3, thickest area-max WT).

RESULTS

23 LVV patients were included, 56.5% giant cells arteritis, 34.8% Takayasu's arteritis and 8.7% isolated aortitis, all Caucasian, mostly females (82%). We considered 32 PET scans for the LVV group (from min. 1 to max. 3 scans/patient) mainly during follow-up (29/32 scans), and 23 PET scans from a control group of non-metastatic malignancies patients. We found higher SUVMax compared to controls, in all sites, irrespective of clinical disease activity. Mean WT resulted higher in patients than in controls but was not correlated to SUVMax. Mean WT positively correlated with age in both cohorts, inversely correlated to disease duration, while no correlation with SUVMax was observed. The concordance between clinically active disease and PET hypermetabolism was poor (K Cohen 0.33).

CONCLUSIONS

PET/MR is a safe imaging technique capable of detecting inflammation in aortic wall. Low radiological exposure of PET/MR should be considered especially in young women receiving follow-up studies.

Treat to Target: A Valid Concept for Management of Polymyalgia Rheumatica and Giant Cell Arteritis?

Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are common inflammatory diseases of the elderly. They have variable clinical courses and are usually treated with glucocorticoids (GCs). Relapses are frequent in both conditions. Physicians should balance the tradeoff of treatment-related adverse events and risk of relapse. The ultimate goal of treatment is control of the disease while maintaining patient well-being. A treat-to-target approach may achieve the aim of controlling inflammation and preserving patient's functioning and quality of life, and would require pursuit and evaluation of clinical, laboratory, imaging, and structural targets to tackle the different manifestations of GCA and PMR.

Advances in Therapies and Imaging for Systemic Vasculitis

Vasculitis is a systemic disease characterized by immune-mediated injury of blood vessels. Current treatments for vasculitis, such as glucocorticoids and alkylating agents, are associated with significant side effects. Furthermore, the management of both small and large vessel vasculitis is challenging because of a lack of robust markers of disease activity. Recent research has advanced our understanding of the pathogenesis of both small and large vessel vasculitis, and this has led to the development of novel biologic therapies capable of targeting key cytokine and cellular effectors of the inflammatory cascade. In parallel, a diverse range of imaging modalities with the potential to monitor vessel inflammation are emerging. Continued expansion of combined structural and molecular imaging using positron emission tomography with computed tomography or magnetic resonance imaging may soon provide reliable longitudinal tracking of vascular inflammation. In addition, the emergence of radiotracers able to assess macrophage activation and immune checkpoint activity represents an exciting new frontier in imaging vascular inflammation. In the near future, these advances will allow more precise imaging of disease activity enabling clinicians to offer more targeted and individualized patient management.

Three-dimensional fat-saturated T1-weighted Cartesian volumetric interpolated breath-hold examination (VIBE) for the diagnosis of aortitis in patients with suspected large vessel vasculitis: a comparative study with 18F-FDG PET applying fully integrated PET/MRI

AIM

To evaluate the feasibility of T1-weighted (T1W) three-dimensional (3D) fat saturated Cartesian volumetric interpolated breath-hold examination (VIBE) magnetic resonance imaging (MRI) sequence for the diagnosis of aortitis in patients with suspected large vessel vasculitis (LVV) applying fully integrated 2-[¹⁸F]-fluoro-2-deoxy-d-glucose (¹⁸F-FDG) positron-emission tomography (PET)/MRI.

MATERIAL AND METHODS

Fourteen patients with aortitis and 14 patients with a negative study for aortitis using ¹⁸F-FDG PET as the standard of reference for the evaluation of inflammatory aortic involvement were included retrospectively. All patients were imaged at 3 T using T1W VIBE pre- and post-contrast. Four aortic segments were evaluated for image quality (IQ), diagnostic confidence (DC), and the degree of inflammatory activity (IA) using a Likert scale. Binomial and generalised estimating equation model tests were used to assess the diagnostic performance of T1W VIBE. Cohen's k was applied to test for interobserver reproducibility with respect to IA. Spearman's rank correlation coefficient was calculated to examine correlations between IQ, DC, IA, and PET results.

RESULTS

On a patient- and segment-based analysis, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 85.7% and 59.8%, 100% and 100%, 100% and 100%, 87.5% and 68%, and 92.9% and 82.1%, respectively. IQ and DC were acceptable to good in all examinations and substantial interobserver agreement was observed for IA (Cohen's k = 0.69). IQ and DC as well as IA and ¹⁸F-FDG vessel wall uptake were significantly correlated (r=0.763 and 0.679, respectively; p<0.0001).

CONCLUSION

T1W 3D fat saturated VIBE MRI allows diagnosis of aortitis and may aid in the management of patients with suspected LVV.

Use of 18F-fluorodeoxyglucose positron emission tomography in the diagnosis of polymyalgia rheumatica-A prospective study of 99 patients

Objective

Previous studies have shown that the majority of patients with PMR have increased 18F-fluorodeoxyglucose (FDG) uptake around the shoulders, hips and processes of the cervical and lumbar spine on PET. The specificity of these findings for PMR is, however, not known.

Methods

We prospectively included 99 consecutive patients with a possible clinical diagnosis of PMR. All patients underwent 18F-FDG-PET scanning before treatment with glucocorticoids was started. The clinical suspicion of PMR was quantified by the treating physician on a scale from 1 to 5. FDG uptake was scored visually in 12 articular regions (scores 0-2) and a total skeletal score was calculated reflecting the FDG uptake in these 12 articular regions. Receiver operating characteristics analysis was performed to determine the optimal clinical and total skeletal score for diagnosing PMR. The gold standard for a diagnosis of PMR was the judgement of an experienced clinician after at least 6 months of follow-up.

Results

Sixty-seven patients were diagnosed with PMR while 32 patients got another diagnosis. A clinical score of 4 or more had a sensitivity of 67.2%, specificity of 87.5%, positive predictive value (PPV) of 91.8% and a negative predictive value (NPV) of 56.0% for the diagnosis of PMR. A total skeletal score of 16 or more had a sensitivity, specificity, PPV and NPV of, respectively, 85.1, 87.5, 93.4 and 73.7%.

Conclusion

18F-FDG-PET before starting glucocorticoid therapy improves the diagnostic accuracy compared with a clinical scoring system in patients with clinical suspicion of PMR.

The Role of Vascular Imaging to Advance Clinical Care and Research in Large-Vessel Vasculitis

Purpose of the Review

The two main forms of large-vessel vasculitis (LVV) are giant cell arteritis (GCA) and Takayasu's arteritis (TAK). Vascular imaging can characterize disease activity and disease extent in LVV. This review critically analyzes the clinical utility of vascular imaging in LVV and highlights how imaging may be incorporated into the management and study of these conditions.

Recent Findings

There are multiple imaging modalities available to assess LVV including ultrasonography, CT angiography (CTA), magnetic resonance angiography (MRA), and ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET). As these techniques are refined, imaging may be increasingly useful to evaluate the cranial arteries and the aorta and its primary branches. In addition, vascular imaging may be useful to monitor disease activity and may have prognostic value to predict future clinical events.

Summary

There are strengths and weaknesses associated with vascular imaging that should be considered when evaluating patients with LVV. Vascular imaging will likely play an increasingly important role in the clinical management of patients and the conduct of research in LVV and may ultimately be incorporated as outcome measures in clinical trials in these conditions.

F-18 FDG PET for assessment of disease activity of large vessel vasculitis: A systematic review and meta-analysis

BACKGROUND

The aim of this study is to investigate the performance of F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) or positron emission tomography/computed tomography (PET/CT) for the assessment of disease activity in patients with large vessel vasculitis (LVV) through a meta-analysis.

METHODS

The MEDLINE via PubMed and EMBASE were searched for the studies evaluating the performance of F-18 FDG PET or PET/CT in the assessment of disease activity in patients with LVV. Pooled sensitivity, specificity, diagnostic odds ratios (DORs), and summary receiver-operating characteristic (sROC) curve were estimated across the included studies. Possible publication bias was assessed by Deek's funnel plot asymmetry tests.

RESULTS

A total of 439 PET images from 298 patients pooled from nine studies showed that the pooled sensitivity was 0.88 [95% confidence interval (CI) 0.79-0.93] without heterogeneity (χ2 = 14.42, P = .07) and the pooled specificity was 0.81 (95% CI 0.64-0.91) with heterogeneity (χ2 = 63.72, P = .00) for the detection of active LVV. The pooled DOR was 30 (95% CI 8-107). Hierarchical sROC curve indicates that the area under the curve was 0.91 (95% CI 0.89-0.94). There was no significant publication bias (P = .42), and meta-regression analysis revealed that none of the variables was the source of the study heterogeneity.

CONCLUSIONS

F-18 FDG PET has a good performance for the detection of active disease status in patients with LVV. Revised criteria for the assessment of disease activity incorporated with F-18 FDG PET or PET/CT should be introduced and validated. Further studies are warranted to determine if PET-based treatment of LVV can improve outcomes.

Large-vessel giant cell arteritis: diagnosis, monitoring and management

GCA is a chronic, idiopathic, granulomatous vasculitis of medium and large arteries. It comprises overlapping phenotypes including classic cranial arteritis and extra-cranial GCA, otherwise termed large-vessel GCA (LV-GCA). Vascular complications associated with LV-GCA may be due, in part, to delayed diagnosis, highlighting the importance of early identification and prompt initiation of effective therapy. Advancements in imaging techniques, including magnetic resonance angiography, CT angiography, PET and colour duplex ultrasonography, have led to improvements in the diagnosis of LV-GCA; however, the role imaging modalities play in the assessment of disease activity and long-term outcomes remains unclear. Glucocorticoids are the mainstay of therapy in LV-GCA, but their prolonged use is associated with multiple, sometimes serious, adverse effects. Recent data suggest that biologic therapies, such as tocilizumab, may be effective and safe steroid-sparing options for patients with GCA. However, data specifically evaluating the management of LV-GCA are limited.

Comparison of magnetic resonance angiography and 18F-fluorodeoxyglucose positron emission tomography in large-vessel vasculitis

OBJECTIVES

To assess agreement between interpretation of magnetic resonance angiography (MRA) and ¹⁸F-fluorodeoxyglucose positron emission tomography (PET) for disease extent and disease activity in large-vessel vasculitis (LVV) and determine associations between imaging and clinical assessments.

METHODS

Patients with giant cell arteritis (GCA), Takayasu's arteritis (TAK) and comparators were recruited into a prospective, observational cohort. Imaging and clinical assessments were performed concurrently, blinded to each other. Agreement was assessed by per cent agreement, Cohen's kappa and McNemar's test. Multivariable logistic regression identified MRA features associated with PET scan activity.

RESULTS

Eighty-four patients (GCA=35; TAK=30; comparator=19) contributed 133 paired studies. Agreement for disease extent between MRA and PET was 580 out of 966 (60%) arterial territories with Cohen's kappa=0.22. Of 386 territories with disagreement, MRA demonstrated disease in more territories than PET (304vs82, p<0.01). Agreement for disease activity between MRA and PET was 90 studies (68%) with Cohen's kappa=0.30. In studies with disagreement, MRA demonstrated activity in 23 studies and PET in 20 studies (p=0.76). Oedema and wall thickness on MRA were independently associated with PET scan activity. Clinical status was associated with disease activity by PET (p<0.01) but not MRA (p=0.70), yet 35/69 (51%) patients with LVV in clinical remission had active disease by both MRA and PET.

CONCLUSIONS

In assessment of LVV, MRA and PET contribute unique and complementary information. MRA better captures disease extent, and PET scan is better suited to assess vascular activity. Clinical and imaging-based assessments often do not correlate over the disease course in LVV.

TRIAL REGISTRATION NUMBER

NCT02257866.

FDG-PET/CT(A) imaging in large vessel vasculitis and polymyalgia rheumatica: joint procedural recommendation of the EANM, SNMMI, and the PET Interest Group (PIG), and endorsed by the ASNC

Large vessel vasculitis (LVV) is defined as a disease mainly affecting the large arteries, with two major variants, Takayasu arteritis (TA) and giant cell arteritis (GCA). GCA often coexists with polymyalgia rheumatica (PMR) in the same patient, since both belong to the same disease spectrum. FDG-PET/CT is a functional imaging technique which is an established tool in oncology, and has also demonstrated a role in the field of inflammatory diseases. Functional FDG-PET combined with anatomical CT angiography, FDG-PET/CT(A), may be of synergistic value for optimal diagnosis, monitoring of disease activity, and evaluating damage progression in LVV. There are currently no guidelines regarding PET imaging acquisition for LVV and PMR, even though standardization is of the utmost importance in order to facilitate clinical studies and for daily clinical practice. This work constitutes a joint procedural recommendation on FDG-PET/CT(A) imaging in large vessel vasculitis (LVV) and PMR from the Cardiovascular and Inflammation & Infection Committees of the European Association of Nuclear Medicine (EANM), the Cardiovascular Council of the Society of Nuclear Medicine and Molecular Imaging (SNMMI), and the PET Interest Group (PIG), and endorsed by the American Society of Nuclear Cardiology (ASNC). The aim of this joint paper is to provide recommendations and statements, based on the available evidence in the literature and consensus of experts in the field, for patient preparation, and FDG-PET/CT(A) acquisition and interpretation for the diagnosis and follow-up of patients with suspected or diagnosed LVV and/or PMR. This position paper aims to set an internationally accepted standard for FDG-PET/CT(A) imaging and reporting of LVV and PMR.

Imaging in diagnosis, outcome prediction and monitoring of large vessel vasculitis: a systematic literature review and meta-analysis informing the EULAR recommendations

Objectives

To perform a systematic literature review on imaging techniques for diagnosis, outcome prediction and disease monitoring in large vessel vasculitis (LVV) informing the European League Against Rheumatism recommendations for imaging in LVV.

Methods

Systematic literature review (until 10 March 2017) of diagnostic and prognostic studies enrolling >20 patients and investigating ultrasound, MRI, CT or positron emission tomography (PET) in patients with suspected and/or established primary LVV. Meta-analyses were conducted, whenever possible, obtaining pooled estimates for sensitivity and specificity by fitting random effects models.

Results

Forty-three studies were included (39 on giant cell arteritis (GCA), 4 on Takayasu arteritis (TAK)). Ultrasound ('halo' sign) at temporal arteries (8 studies, 605 patients) and MRI of cranial arteries (6 studies, 509 patients) yielded pooled sensitivities of 77% (95% CI 62% to 87%) and 73% (95% CI 57% to 85%), respectively, compared with a clinical diagnosis of GCA. Corresponding specificities were 96% (95% CI 85% to 99%) and 88% (95% CI 81% to 92%). Two studies (93 patients) investigating PET for GCA diagnosis reported sensitivities of 67%-77% and specificities of 66%-100% as compared with clinical diagnosis or temporal artery biopsy. In TAK, one study each evaluated the role of magnetic resonance angiography and CT angiography for diagnostic purposes revealing both a sensitivity and specificity of 100%. Studies on outcome prediction and monitoring disease activity/damage were limited and mainly descriptive.

Conclusions

Ultrasound and MRI provide a high diagnostic value for cranial GCA. More data on the role of imaging for diagnosis of extracranial large vessel GCA and TAK, as well as for outcome prediction and monitoring in LVV are warranted.

Repetitive 18F-FDG-PET/CT in patients with large-vessel giant-cell arteritis and controlled disease

OBJECTIVE

¹⁸F-FDG PET/CT can detect large-vessel involvement in giant-cell arteritis (GCA) with a good sensitivity. In patients with clinically and biologically controlled disease, we aimed to assess how vascular uptakes evolve on repetitive FDG-PET/CT.

PATIENTS AND METHODS

All included patients had to satisfy the 4 following criteria: 1) diagnosis of GCA was retained according to the criteria of the American College of Rheumatology or based on the satisfaction of 2 criteria associated with the demonstration of large-vessel involvement on FDG-PET/CT; 2) all patients had a positive PET/CT that was performed at diagnosis before treatment or within the first 10days of treatment; 3) another FDG-PET/CT was performed after at least 3months of controlled disease without any relapse; 4) patients were followed-up at least for 12months.

RESULTS

Twenty-five patients (17 [68%] women, median age: 69 [65-78]) with large-vessel inflammation on a baseline FDG-PET/CT and with repetitive imaging during the period with controlled disease were included and followed-up for 62 [25-95] months. Four repeated procedures revealed total extinction of vascular uptakes at 11.5 [8-12] months after the first FDG-PET/CT. Eight PET/CT revealed decreased numbers of vascular uptakes, and 10 procedures revealed no changes. The 3 remaining procedures indicated worsening of the numbers of vascular uptakes in the absence of relapse.

CONCLUSIONS

Our study revealed long-term persistent vascular uptake on repeated FDG-PET/CT in >80% of our GCA patients with large-vessel inflammation and clinical-biological controlled disease. Prospective studies are required to confirm these findings.

Paediatric nuclear medicine imaging

BACKGROUND

Nuclear medicine imaging explores tissue viability and function by using radiotracers that are taken up at cellular level with different mechanism. This imaging technique can also be used to assess blood flow and transit through tubular organs. Nuclear medicine imaging has been used in paediatrics for decades and this field is continuously evolving.

SOURCES OF DATA

The data presented comes from clinical experience and some milestone papers on the subject.

AREAS OF AGREEMENT

Nuclear medicine imaging is well-established in paediatric nephro-urology in the context of urinary tract infection, ante-natally diagnosed hydronephrosis and other congenital renal anomalies. Also, in paediatric oncology, I-123-meta-iodobenzyl-guanidine has a key role in the management of children with neuroblastic tumours. Bone scintigraphy is still highly valuable to localize the source of symptoms in children and adolescents with bone pain when other imaging techniques have failed. Thyroid scintigraphy in neonates with congenital hypothyroidism is the most accurate imaging technique to confirm the presence of ectopic functioning thyroid tissue.

AREAS OF CONTROVERSY

Radionuclide transit studies of the gastro-intestinal tract are potentially useful in suspected gastroparesis or small bowel or colonic dysmotility. However, until now a standardized protocol and a validated normal range have not been agreed, and more work is necessary. Research is ongoing on whether magnetic resonance imaging (MRI), with its great advantage of great anatomical detail and no ionizing radiations, can replace nuclear medicine imaging in some clinical context. On the other hand, access to MRI is often difficult in many district general hospitals and general anaesthesia is frequently required, thus adding to the complexity of the examination.

GROWING POINTS

Patients with bone pain and no cause for it demonstrated on MRI can benefit from bone scintigraphy with single photon emission tomography and low-dose computed tomography. This technique can identify areas of mechanical stress at cortical bone level, difficult to demonstrate on MRI, which can act as pain generators. Positron emission tomography (PET) is being tested in the staging, response assessment and at the end of treatment of several paediatric malignancies. PET is becoming more widely utilized in neurology in the pre-surgical assessment of some children with drug resistant epilepsy.

AREAS TIMELY FOR DEVELOPING RESEARCH

The use of PET/MRI scanners is very attractive as it combines benefits of MR imaging with the assessment of cellular viability and metabolism with PET in one examination. This imaging technique will allow important research on tumour in-vivo metabolism (possible applications include lymphomas, neuroblastomas, malignant germ cell tumours andbrain tumours), with the aim of offering a personalized biological profile of the tumour in a particular patient. Ground-breaking research is also envisaged in neurosciences, especially in epilepsy, using PET tracers that would enable a better identification of the epileptogenic focus, and in psychiatry, with the use of radiolabeled neurotransmitters. In paediatric nephro-urology, the identification of the asymptomatic child with ante-natally diagnosed hydronephrosis at risk of losing renal parenchymal function if left untreated is another area of active research involving radionuclide renography.

Giant-cell arteritis: concordance study between aortic CT angiography and FDG-PET/CT in detection of large-vessel involvement

PURPOSE

The purpose of our study was to assess the concordance of aortic CT angiography (CTA) and FDG-PET/CT in the detection of large-vessel involvement at diagnosis in patients with giant-cell arteritis (GCA).

METHODS

We created a multicenter cohort of patients with GCA diagnosed between 2010 and 2015, and who underwent both FDG-PET/CT and aortic CTA before or in the first ten days following treatment introduction. Eight vascular segments were studied on each procedure. We calculated concordance between both imaging techniques in a per-patient and a per-segment analysis, using Cohen's kappa concordance index.

RESULTS

We included 28 patients (21/7 women/men, median age 67 [56-82]). Nineteen patients had large-vessel involvement on PET/CT and 18 of these patients also presented positive findings on CTA. In a per-segment analysis, a median of 5 [1-7] and 3 [1-6] vascular territories were involved on positive PET/CT and CTA, respectively (p = 0.03). In qualitative analysis, i.e., positivity of the procedure suggesting a large-vessel involvement, the concordance rate between both procedures was 0.85 [0.64-1]. In quantitative analysis, i.e., per-segment analysis in both procedures, the global concordance rate was 0.64 [0.54-0.75]. Using FDG-PET/CT as a reference, CTA showed excellent sensitivity (95%) and specificity (100%) in a per-patient analysis. In a per-segment analysis, sensitivity and specificity were 61% and 97.9%, respectively.

CONCLUSIONS

CTA and FDG-PET/CT were both able to detect large-vessel involvement in GCA with comparable results in a per-patient analysis. However, PET/CT showed higher performance in a per-segment analysis, especially in the detection of inflammation of the aorta's branches.

Polymyalgia rheumatica and giant cell arteritis-three challenges-consequences of the vasculitis process, osteoporosis, and malignancy: A prospective cohort study protocol

INTRODUCTION

Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) are common inflammatory conditions. The diagnosis of PMR/GCA poses many challenges since there are no specific diagnostic tests. Recent literature emphasizes the ability of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) to assess global disease activity in inflammatory diseases. 18F-FDG PET/CT may lead to the diagnosis at an earlier stage than conventional imaging and may also assess response to therapy. With respect to the management of PMR/GCA, there are 3 significant areas of concern as follows: vasculitis process/vascular stiffness, malignancy, and osteoporosis.

METHODS AND ANALYSIS

All patients with suspected PMR/GCR referred to the Rheumatology section of Medicine Department at Svendborg Hospital, Denmark. The 4 separate studies in the current protocol focus on: the association of clinical picture of PMR/GCA with PET findings; the validity of 18F-FDG PET/CT scan for diagnosis of PMR/GCA compared with temporal artery biopsy; the prevalence of newly diagnosed malignancies in patients with PMR/GCA, or PMR-like syndrome, with the focus on diagnostic accuracy of 18F-FDG PET/CT scan compared with conventional workup (ie, chest X-ray/abdominal ultrasound); and the impact of disease process, and also steroid treatment on bone mineral density, body composition, and vasculitis/vascular stiffness in PMR/GCA patients.

ETHICS AND DISSEMINATION

The study has been approved by the Regional Ethics Committee of the Region of Southern Denmark (identification number: S-20160098) and Danish Data Protection Agency (J.nr 16/40522). Results of the study will be disseminated via publications in peer-reviewed journals, and presentation at national and international conferences.

The Birmingham Vasculitis Activity Score as a Measure of Disease Activity in Patients with Giant Cell Arteritis

OBJECTIVE

To evaluate the performance of the Birmingham Vasculitis Activity Score (BVAS) in the assessment of disease activity in giant cell arteritis (GCA).

METHODS

Patients with GCA enrolled in a prospective, multicenter, longitudinal study with symptoms of active vasculitis during any visit were included. Spearman's rank correlation was used to explore the association of the BVAS with other measures of disease activity.

RESULTS

During a mean (SD) followup of 2.3 (1.6) years, symptoms of active GCA were present in 236 visits in 136 subjects (100 female, 74%). Median (range) BVAS1 (new/worse symptoms) was 1 (0-10) and median (range) BVAS2 (persistent symptoms) was 0 (0-5). Median (range) physician's global assessment (PGA) was 4 (0-9) for disease activity in the past 28 days and 2 (0-9) for activity on the day of the visit. Important ischemic manifestations of active vasculitis not recorded by the BVAS included tongue/jaw claudication (27%), upper extremity claudication (15%), lower extremity claudication (5%), carotidynia (7%), and ischemic retinopathy (5%). During 25 visits (11%) with active disease, all symptoms of active vasculitis were placed in the "Other" category yet still resulted in a BVAS1 and BVAS2 of 0. BVAS1 moderately correlated with PGA for the past 28 days (Spearman's correlation 0.50) and physician-rated disease activity for the past 28 days (Spearman's correlation 0.46).

CONCLUSION

The BVAS has limited utility in GCA. Patients with active GCA can have a BVAS of 0. Many important ischemic symptoms attributable to active vasculitis are not included in the composite score.

Assessment of Therapy Response by FDG PET in Infection and Inflammation

Positron emission tomography (PET) is a well-known imaging modality in assessing the treatment response to chemotherapy or radiotherapy in various malignancies. A systematic review of the literature reveals a few publications reporting evaluation of the treatment response in benign conditions using PET/computed tomography. PET holds a promising future role in the follow-up of inflammatory or infectious diseases. In this article, [(18)F]Fluorodeoxyglucose PET as a tool in the evaluation, treatment, and follow-up of infectious and inflammatory diseases is discussed.

Imaging in Giant Cell Arteritis

Much progress has been made in the use of imaging as a diagnostic tool in giant cell arteritis (GCA), which assists in the management of patients where the initial diagnosis is unclear. This includes patients with atypical cranial symptoms, or with predominantly systemic, constitutional or limb symptoms. Ultrasound and magnetic resonance imaging are capable of visualising both the cranial and extracranial large vessel circulation, with vessel wall thickening and stenotic lesions being visualised. Computed tomographic angiography is helpful in visualising the aorta for aneurysm complicating GCA but can also detect vessel wall thickening in established large vessel vasculitis. PET-CT is a very sensitive test for early vascular inflammation in extracranial large vessel vasculitis, before aneurysmal or stenotic lesions have developed, of use in the patient with unexplained constitutional symptoms. The place of imaging in the follow-up of GCA is being investigated, and repeated imaging may be useful in select cases. Generally, vascular abnormalities become less defined once glucocorticoid treatment has been started, and therefore, imaging studies must be conducted early as part of a GCA fast-track assessment.

MRI parametric monitoring of biological therapies in primary large vessel vasculitides: a pilot study

OBJECTIVE

To evaluate the development of characteristic MRI changes in patients with primary large-vessel vasculitis (LVV) when treated with biological therapies.

METHODS

12 patients with primary LVV (8 patients with Takayasu arteritis and 4 patients with giant-cell arteritis) received biological therapy with tumour necrosis factor-α blockers (n = 9) or an interleukin-6 inhibitor (n = 3). MRI investigations were performed at baseline (pre-treatment) and follow-up. All patients underwent the same MRI/MR angiography (MRA) protocol. Laboratory parameters (C-reactive protein and erythrocyte sedimentation rate) and clinical response (Birmingham Vasculitis Activity Score) were assessed.

RESULTS

Wall thickness was 4.2 ± 0.3 mm pre-treatment and significantly decreased to 3.2 ± 0.3 mm post treatment in 9/12 patients. Mural enhancement was increased in all 12/12 patients with LVV, and subsided with therapy in 5/12 patients. Mural oedema or ill-defined contour were less prevalent but also improved with biological treatment. C-reactive protein and erythrocyte sedimentation rate levels decreased, and clinical assessment revealed a significant improvement from pre-treatment to post-treatment. However, the course of imaging characteristics often did not parallel that of laboratory or clinical parameters. In all three patients receiving interleukin-6 blockade, laboratory markers and clinical scores normalized despite persistent vascular inflammation in one patient which was disclosed by MRI.

CONCLUSION

Contrast-enhanced MRI/MRA may be useful when evaluating the development of disease activity in primary LVV under biological therapies. A high degree of suspicion and regular imaging follow-up is needed to detect persistent inflammation.

ADVANCES IN KNOWLEDGE

This is the first study investigating the applicability of different MRI/MRA parameters for monitoring biological therapy in patients with primary LVV.

Giant cell arteritis: Current treatment and management

Glucocorticoids remain the cornerstone of medical therapy in giant cell arteritis (GCA) and should be started immediately to prevent severe consequences of the disease, such as blindness. However, glucocorticoid therapy leads to significant toxicity in over 80% of the patients. Various steroid-sparing agents have been tried, but robust scientific evidence of their efficacy and safety is still lacking. Tocilizumab, a monoclonal IL-6 receptor blocker, has shown promising results in a number of case series and is now being tested in a multi-centre randomized controlled trial. Other targeted treatments, such as the use of abatacept, are also now under investigation in GCA. The need for surgical treatment is rare and should ideally be performed in a quiescent phase of the disease. Not all patients follow the same course, but there are no valid biomarkers to assess therapy response. Monitoring of disease progress still relies on assessing clinical features and measuring inflammatory markers (C-reactive protein and erythrocyte sedimentation rate). Imaging techniques (e.g., ultrasound) are clearly important screening tools for aortic aneurysms and assessing patients with large-vessel involvement, but may also have an important role as biomarkers of disease activity over time or in response to therapy. Although GCA is the most common form of primary vasculitis, the optimal strategies for treatment and monitoring remain uncertain.

¹⁸F-FDG PET/CT for Therapy Control in Vascular Graft Infections: A First Feasibility Study

The aim of this study was to evaluate the clinical value of PET/CT with (18)F-FDG for therapy control in patients with prosthetic vascular graft infections (PVGIs).

METHODS

In this single-center, observational, prospective cohort study, 25 patients with a median age of 66 y (range, 48-81 y) who had a proven PVGI were included. Follow-up (18)F-FDG PET/CT was performed at a median of 170 d (range, 89-249 d) after baseline examination. Two independent and masked interpreters measured maximum standardized uptake values to quantify metabolic activity and analyzed whole-body datasets for a secondary diagnosis (i.e., infectious foci not near the graft). The metabolic activity of the graft was correlated with clinical information and 2 laboratory markers (C-reactive protein and white blood cell count).

RESULTS

(18)F-FDG PET/CT had an impact on management in all patients. In 19 of 25 patients (76%), antibiotic treatment was continued because of the results of follow-up (18)F-FDG PET/CT. Antibiotic treatment was stopped or changed in 8% and 16% of patients, respectively. In 8 patients (32%), additional incidental findings were detected on follow-up (18)F-FDG PET/CT and had a further impact on patient management. Only in a subgroup of patients with PVGI and no other sites of infection was a significant correlation found between the difference in C-reactive protein at the time of baseline and follow-up (18)F-FDG PET/CT and the difference in maximum standardized uptake value (n = 11; R(2) = 0.67; P = 0.002).

CONCLUSION

(18)F-FDG PET/CT represents a useful tool in therapy monitoring of PVGI and has an impact on patient management.

Positron emission tomography scanning in anti-neutrophil cytoplasmic antibodies-associated vasculitis

Tools for evaluation of disease activity in patients with anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) include scoring clinical manifestations, determination of biochemical parameters of inflammation, and obtaining tissue biopsies. These tools, however, are sometimes inconclusive. 2-deoxy-2-[F]-fluoro-D-glucose (FDG) positron emission tomography (PET) scans are commonly used to detect inflammatory or malignant lesions. Our objective is to explore the ability of PET scanning to assess the extent of disease activity in patients with AAV.Consecutive PET scans made between December 2006 and March 2014 in Maastricht (MUMC) and between July 2008 and June 2013 in Brussels (EUH) to assess disease activity in patients with AAV were retrospectively included. Scans were re-examined and quantitatively scored using maximum standard uptake values (SUVmax). PET findings were compared with C-reactive protein (CRP) and ANCA positivity at the time of scanning.Forty-four scans were performed in 33 patients during a period of suspected active disease. All but 2 scans showed PET-positive sites, most commonly the nasopharynx (n = 22) and the lung (n = 22). Forty-one clinically occult lesions were found, including the thyroid gland (n = 4 patients), aorta (n = 8), and bone marrow (n = 7). The amount of hotspots, but not the highest observed SUVmax value, was higher if CRP levels were elevated. Seventeen follow-up scans were made in 13 patients and showed decreased SUVmax values.FDG PET scans in AAV patients with active disease show positive findings in multiple sites of the body even when biochemical parameters are inconclusive, including sites clinically unsuspected and difficult to assess otherwise.

FDG PET/CT in infection and inflammation--current and emerging clinical applications

Integrated positron emission tomography/computed tomography (PET/CT) with the glucose analogue, 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG), is an evolving hybrid imaging technique in the evaluation of an important and diverse group of pathological conditions, which are characterised by infection and aseptic inflammation. With a rapidly expanding body of evidence, it is being increasingly recognised that, in addition to its established role in oncological imaging, FDG PET/CT also has clinical utility in suspected infection and inflammation. The technique can identify the source of infection or inflammation in a timely fashion ahead of morphological changes on conventional anatomical imaging techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI), map the extent and severity of disease, identify sites for tissue sampling, and assess therapy response. FDG PET/CT exhibits distinct advantages over traditional radionuclide imaging techniques in terms of shorter duration of examination, higher spatial resolution, non-invasive nature of acquisition, ability to perform quantitative analyses, and the provision of a synergistic combination of functional and anatomical imaging. With the use of illustrative clinico-radiological cases, this article discusses the current and emerging evidence for the use of FDG PET/CT in a broad spectrum of disorders, such as fever of unknown origin, sarcoidosis, large vessel vasculitis, musculoskeletal infections, joint prosthesis or implant-related complications, human immunodeficiency virus (HIV)-related infections, and miscellaneous indications, such as IgG4-related systemic disease. It will also briefly summarise the role of more novel tracers such as FDG-labelled leukocytes and gallium-68 PET tracers in this arena.

Management of large-vessel vasculitis with FDG-PET: a systematic literature review and meta-analysis

We aimed to clarify the role of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in the management of large-vessel vasculitis (LVV), focusing on 3 issues which are as follows: describe and determine the different FDG-PET criteria for the diagnosis of vascular inflammation, the performance of FDG-PET for the diagnosis of large-vessel inflammation in giant cell arteritis (GCA) patients, and the performance of FDG-PET to evaluate the disease inflammatory activity in Takayasu arteritis (TA) patients. MEDLINE, Cochrane Library, and EMBASE database were searched for articles that evaluated the value of FDG-PET in LVV, from January 2000 to December 2013. Inclusion criteria were American College of Rheumatology criteria for GCA or TA, definition PET positivity threshold, and >4 cases included. Sensitivity (Se) and specificity (Sp) of FDG-PET for the diagnosis of large-vessel inflammation were calculated from each included individual study, and then pooled for meta-analysis with a random-effects model. Twenty-one studies (413 patients, 299 controls) were included in the systematic review. FDG-PET showed FDG vascular uptake in 70% (288/413) of patients and 7% (22/299) of controls. Only vascular uptake equal to or higher than the liver uptake was significantly different between GCA/TA patients and controls (P < 0.001). The meta-analysis of GCA patients (4 studies, 57 patients) shows that FDG-PET has high Se and Sp for the diagnosis of large-vessel inflammation in GCA patients in comparison to controls, with a pooled Se at 90% (95% confidence interval [CI], 79%-93%) and a pooled Sp at 98% (95% CI, 94%-99%). The meta-analysis of TA patients (7 studies, 191 patients) shows that FDG-PET has a pooled Se at 87% (95% CI, 78%-93%) and Sp at 73% (95% CI, 63%-81%) for the assessment of disease activity in TA, with up to 84% Sp, with studies using National Institutes of Health criteria as the disease activity assessment scale. FDG-PET showed good performances in the diagnosis of large-vessel inflammation, with higher accuracy in GCA patients than in TA patients. Although a vascular uptake equal to or higher than the liver uptake appears to be a good criterion for the diagnosis of vascular inflammation, further studies are needed to define the threshold of significance as well as the clinical significance of the vascular uptake.

Impact of cranial and axillary/subclavian artery involvement by color duplex sonography on response to treatment in giant cell arteritis

OBJECTIVE

Color duplex sonography (CDS) today is broadly used in the diagnostic workup of patients with suspected cranial or extracranial giant cell arteritis (GCA). This study aimed to determine the prognostic impact of the disease pattern assessed by CDS on the treatment response in GCA.

METHODS

This was a retrospective, longitudinal follow-up study of 43 patients who were diagnosed with GCA at our institution between 2002 and 2010. All patients underwent CDS of the temporal and subclavian/axillary arteries at baseline and were observed for at least 6 months. Vasculitis was sonographically characterized by a circumferential, hypoechogenic wall thickening. According to the CDS findings, patients were categorized into patients with involvement of the subclavian/axillary arteries only (group A1, n = 17), patients with involvement of both the subclavian/axillary arteries and the temporal arteries (group A2, n = 9), and patients with isolated cranial GCA (group B, n = 17). Data on recurrences, corticosteroid doses, and steroid-sparing agents were extracted from the medical records. Treatment response over time was analyzed by Kaplan-Meier curves with log-rank testing.

RESULTS

The mean follow-up time was 25.4 months and did not differ between groups (P = .4). Patients in group A1 were significantly younger than patients in groups A2 and B (P < .01). The interval between symptom onset and diagnosis was significantly longer in groups A1 and A2 compared with group B (P < .01). The number of recurrences per month was significantly higher in group A2 compared with group A1 and group B (A1, 0.07; A2, 0.13; B, 0.03; P < .01). Whereas there were no significant differences in the mean time until a daily prednisolone dose <10 mg was reached, patients in group A2 more frequently required steroid-sparing agents (A1, 24%; A2, 56%; B, 24%; P = .04).

CONCLUSIONS

Extensive vascular involvement of both the temporal and subclavian/axillary arteries, as depicted by CDS, may be associated with a poor treatment response in GCA.

Large-vessel vasculitis: interobserver agreement and diagnostic accuracy of 18F-FDG-PET/CT

Introduction. ¹⁸F-FDG-PET visualises inflammation. Both atherosclerosis and giant cell arteritis cause vascular inflammation, but distinguishing the two may be difficult. The goal of this study was to assess interobserver agreement and diagnostic accuracy of ¹⁸F-FDG-PET for the detection of large artery involvement in giant cell arteritis (GCA). Methods. 31 ¹⁸F-FDG-PET/CT scans were selected from 2 databases. Four observers assessed vascular wall ¹⁸F-FDG uptake, initially without and subsequently with predefined observer criteria (i.e., vascular wall ¹⁸F-FDG uptake compared to liver or femoral artery ¹⁸F-FDG uptake). External validation was performed by two additional observers. Sensitivity and specificity of ¹⁸F-FDG-PET were determined by comparing scan results to a consensus diagnosis. Results. The highest interobserver agreement (kappa: 0.96 in initial study and 0.79 in external validation) was observed when vascular wall ¹⁸F-FDG uptake higher than liver uptake was used as a diagnostic criterion, although agreement was also good without predefined criteria (kappa: 0.68 and 0.85). Sensitivity and specificity were comparable for these methods. The criterion of vascular wall ¹⁸F-FDG uptake equal to liver ¹⁸F-FDG uptake had low specificity. Conclusion. Standardization of image assessment for vascular wall ¹⁸F-FDG uptake promotes observer agreement, enables comparative studies, and does not appear to result in loss of diagnostic accuracy compared to nonstandardized assessment.

Crohns disease with central nervous system vasculitis causing subarachnoid hemorrhage due to aneurysm and cerebral ischemic stroke

Cerebral vasculitis secondary to Crohn's disease (CD) seems to be a very rare phenomenon. We report a 39-year-old male who presented with headache, vomiting, and left-sided weakness in the known case of CD. Cross-sectional imaging (computed tomography and magnetic resonance imaging,) showed right gangliocapsular acute infarct with supraclinoid cistern subarachnoid hemorrhage (SAH). Cerebral digital substraction angiography (DSA) showed dilatation and narrowing of right distal internal carotid artery (ICA). Left ICA was chronically occluded. His inflammatory markers were significantly raised. Imaging features are suggestive of cerebral vasculitis. Arterial and venous infarcts due to thrombosis are known in CD. Our case presented with acute subarachnoid hemorrhage in supraclinoid cistern due to rupture of tiny aneurysm of perforator arteries causing SAH and infarction in right basal ganglia. Patient was treated conservatively with immunosuppression along with medical management of SAH.

Giant cell arteritis: a systematic review of the qualitative and semiquantitative methods to assess vasculitis with 18F-fluorodeoxyglucose positron emission tomography

Giant cell arteritis (GCA) is the most common vasculitis affecting medium and large vessels. It shows a close clinical association with polymyalgia rheumatica (PMR), a musculoskeletal inflammatory disorder, which is clinically characterized by girdles pain and stiffness. 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) is an effective tool for the diagnosis, grading, and follow-up of patients affected by GCA involving the aorta and its proximal branches, but the lack of a standardized method for the assessment of vascular inflammation remains a critical issue, potentially leading to misclassification. In our systematic review, including 19 original articles for a total of 442 GCA patients (with or without PMR symptoms) and 535 healthy controls, we described the different qualitative, semiquantitative and combined methods that have been proposed throughout the literature for assessing the presence and grading the severity of GCA-related vascular inflammation on 18F-FDG PET scans, focusing on the diagnostic performance and examining their respective advantages and limitations. The majority of the included studies adopted qualitative methods of PET image analysis, which are less sensitive but more specific than semiquantitative ones. Among the semiquantitative approaches, the aortic-to-blood pool uptake ratio of the aortic arch seems to be the most accurate method.

The role of 18F-FDG PET/CT in large-vessel vasculitis: appropriateness of current classification criteria?

Patients with clinical suspicion of large-vessel vasculitis (LVV) may present with nonspecific signs and symptoms and increased inflammatory parameters and may remain without diagnosis after routine diagnostic procedures. Both the nonspecificity of the radiopharmaceutical ¹⁸F-FDG and the synergy of integrating functional and anatomical images with PET/CT offer substantial benefit in the diagnostic work-up of patients with clinical suspicion for LVV. A negative temporal artery biopsy, an ultrasonography without an arterial halo, or a MRI without aortic wall thickening or oedema do not exclude the presence of LVV and should therefore not exclude the use of ¹⁸F-FDG PET/CT when LVV is clinically suspected. This overview further discusses the notion that there is substantial underdiagnosis of LVV. Late diagnosis of LVV may lead to surgery or angioplasty in occlusive forms and is often accompanied by serious aortic complications and a fatal outcome. In contrast to the American College of Rheumatology 1990 criteria for vasculitis, based on late LVV effects like arterial stenosis and/or occlusion, ¹⁸F-FDG PET/CT sheds new light on the classification of giant cell arteritis (GCA) and Takayasu arteritis (TA). The combination of these observations makes the role of ¹⁸F-FDG PET/CT in the assessment of patients suspected for having LVV promising.