Imaging of vasculitis: State of the art

Fibroblast activation protein inhibitor-positron emission tomography in aortitis: fibroblast pathology in active inflammation and remission

OBJECTIVES

Epigenetically modified fibroblasts contribute to chronicity in inflammatory diseases. Reasons for the relapsing character of large vessel vasculitis (LVV) remain obscure, including the role of fibroblasts, in part due to limited access to biopsies of involved tissue.68Ga FAPI-46 (FAPI)-PET/CT detects activated fibroblasts in vivo. In this exploratory pilot study, we tested the detection of fibroblast activation in vessel walls using FAPI-PET/CT in LVV with aortitis.

METHODS

Eight LVV patients with aortitis and eight age- and gender-matched controls were included. The distribution of FAPI uptake was evaluated in the aorta and large vessels. FAPI-uptake was compared with MRI inflammatory activity scores. Imaging results were compared with clinical parameters such as serum inflammatory markers, time of remission and medication.

RESULTS

Three aortitis patients were clinically active and five in remission. Irrespective of activity, FAPI uptake was significantly enhanced in aortitis compared with controls. Patients in remission had a mean duration of remission of 2.8 years (range 1-4 years), yet significant FAPI uptake in the vessel wall was found. In remitted aortitis, MRI inflammatory scores were close to be negative, while in 4/5 patients visually identifiable FAPI uptake was observed.

CONCLUSIONS

This pilot feasibility study shows significant tracer uptake in the aortic walls in LVV. FAPI positivity indicates ongoing fibroblast pathology in clinically remitted LVV.

Treatment of giant cell arteritis with ultra-short glucocorticoids and tocilizumab: the role of imaging in a prospective observational study

OBJECTIVES

To assess the impact of tocilizumab (TCZ) monotherapy after ultra-short-pulse glucocorticoids (GCs) on clinical manifestations, and vessel inflammation and damage in large vessel-GCA (LV-GCA).

METHODS

In this prospective observational study, we enrolled patients with active LV-GCA. All patients received 500 mg per day i.v. methylprednisolone for three consecutive days and weekly s.c. TCZ injections from day 4 until week 52. PET/CT was performed on all patients at baseline and at weeks 24 and 52. The primary end points were the reduction in the PET vascular activity score (PETVAS) at weeks 24 and 52 compared with baseline, and the proportion of patients with relapse-free remission at weeks 24 and 52. The secondary end point was the proportion of patients with new aortic dilation at weeks 24 and 52.

RESULTS

A total of 18 patients were included (72% female, mean age 68.5 years). Compared with the baseline value, a significant reduction in the PETVAS was observed at weeks 24 and 52, mean (95% CI) reductions -8.6 (-11.5 to -5.7) and -10.4 (-13.6 to -7.2), P = 0.001 and 0.002, respectively. The proportion of patients with relapse-free remission at weeks 24 and 52 was 10/18 (56%, 95% CI 31-78) and 8/17 (47%, 95% CI 23-72), respectively. At weeks 24 and 52, no patient had shown new aortic dilation. However, 4 patients who had shown aortic dilation at baseline showed a significant increase in aortic diameter (≥5 mm) at week 52.

CONCLUSION

TCZ monotherapy after ultra-short-pulse GCs controlled the clinical symptoms of GCA and reduced vascular inflammation.

TRIAL REGISTRATION

ClinicalTrials.gov, https://clinicaltrials.gov, NCT05394909.

Non-infectious diseases of the aorta and large arteries

This article describes the various forms of inflammatory lesions of the aorta and large arteries, including chronic periaortitis, as well as the diagnostic methods are considered. Large vessel vasculitis represent the most common entities, however, there is also an association with other rheumatological or inflammatory diseases, drug-induced or paraneoplastic entities. Instrumental imaging modalities play an important role in the diagnosis.

The role of PET/CT in disease activity assessment in patients with large vessel vasculitis

OBJECTIVES

To evaluate the accuracy of PET/CT and of PET vascular activity score (PETVAS) in assessing disease activity and the ability of PETVAS in predicting relapses in a large single-centre cohort of patients with large vessel vasculitis (LVV).

METHODS

We conducted a retrospective cohort study of prospectively collected data of consecutive patients diagnosed with LVV who underwent at least one PET/CT scan between 2007 and 2020. The nuclear medicine physician's interpretation of each PET/CT scan (active/inactive vasculitis) was compared with disease activity clinical judgement (active disease/remission). For each PET/CT scan, the PETVAS score was calculated and its accuracy in assessing disease activity was evaluated. The ability of PETVAS in predicting subsequent relapses was evaluated.

RESULTS

A total of 100 consecutive LVV patients (51 large vessel GCA, 49 Takayasu arteritis) underwent a total of 476 PET/CT scans over a mean follow-up period of 97.5 months. Physician-determined PET/CT grading was able to distinguish between clinically active and inactive LVV with a sensitivity of 60% (95% CI 50.9, 68.7) and specificity of 80.1% (95% CI 75.5, 84.1); the area under the curve (AUC )was 0.70 (95% CI 0.65, 0.75). PETVAS was associated with disease activity, with an age and sex-adjusted odds ratio for active disease of 1.15 (95% CI 1.11, 1.19). A PETVAS ≥10 provided 60.8% sensitivity and 80.6% specificity in differentiating between clinically active and inactive LVV; the AUC was 0.73 (95% CI 0.68, 0.79). PETVAS was not associated with subsequent relapses, with an age and sex-adjusted hazard ratio of 1.04 (95% CI 0.97, 1.11).

CONCLUSIONS

The visual PET/CT grading scale and PETVAS had moderate accuracy to distinguish active LVV from remission. PETVAS did not predict disease relapses.

Pediatric cardiothoracic vasculitis: multimodality imaging review

The pediatric vasculitides are a relatively uncommon and heterogeneous group of disorders characterized by vessel inflammation, often with cardiothoracic involvement. Diagnosis and monitoring are often clinically challenging because of the nonspecific symptoms and laboratory markers. Thus, imaging has assumed increasing importance for early detection of disease activity, extent and complications as well as long-term monitoring pre- and post-treatment. Herein, we review the major pediatric vasculitides with frequent chest manifestations, including Takayasu arteritis, Kawasaki disease, granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, microscopic polyangiitis, Behçet disease and potential mimics. We highlight key clinical features and management considerations, emphasizing the central role of imaging.

ACR Appropriateness Criteria® Noncerebral Vasculitis

Noncerebral vasculitis is a wide-range noninfectious inflammatory disorder affecting the vessels. Vasculitides have been categorized based on the vessel size, such as large-vessel vasculitis, medium-vessel vasculitis, and small-vessel vasculitis. In this document, we cover large-vessel vasculitis and medium-vessel vasculitis. Due to the challenges of vessel biopsy, imaging plays a crucial role in diagnosing this entity. While CTA and MRA can both provide anatomical details of the vessel wall, including wall thickness and enhancement in large-vessel vasculitis, FDG-PET/CT can show functional assessment based on the glycolytic activity of inflammatory cells in the inflamed vessels. Given the size of the vessel in medium-vessel vasculitis, invasive arteriography is still a choice for imaging. However, high-resolution CTA images can depict small-caliber aneurysms, and thus can be utilized in the diagnosis of medium-vessel vasculitis. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Vascular Imaging Techniques to Diagnose and Monitor Patients with Takayasu Arteritis: A Review of the Literature

Takayasu arteritis (TA) is a large vessel vasculitis that causes stenosis, occlusion, and sometimes the aneurysm of the aorta and its major branches. TA often occurs in young women, and because the symptoms are not obvious in the early stages of the disease, diagnosis is difficult and often delayed. In approximately 10% to 20% of patients, TA is reportedly complicated by ischemic stroke or transient ischemic attack. It is important to diagnose TA early and provide appropriate treatment to prevent complications from stroke. Diagnostic imaging techniques to visualize arterial stenosis are widely used in clinical practice. Even if no signs of cerebrovascular events are present at the time of the most recent evaluation of patients with TA, follow-up vascular imaging is important to monitor disease progression and changes in the cerebrovascular risk. However, the optimal imaging technique for monitoring of TA has not been established. Therefore, the purpose of this review is to describe newly available evidence on the usefulness of conventional imaging modalities (digital subtraction angiography, computed tomography angiography, magnetic resonance imaging/angiography, duplex ultrasound, and positron emission tomography) and novel imaging modalities (optical coherence tomography, infrared thermography, contrast-enhanced ultrasonography, and superb microvascular imaging) in the diagnosis and monitoring of TA.

Resolution of vascular inflammation in patients with new-onset giant cell arteritis: data from the RIGA study

OBJECTIVES

Efficacy evaluation of GCA treatment is primarily based on non-specific symptoms and laboratory markers. We aimed to assess the change in vascular inflammation in patients with large vessel (LV)-GCA under different treatments using [18F]FDG PET/CT.

METHODS

Observational study on patients with new-onset, active LV-GCA starting treatment with either prednisolone monotherapy (PRED) or combination with MTX or tocilizumab (TOC). All patients underwent baseline and follow-up PET/CT. The aorta and its major branches were assessed using PET vascular activity score (PETVAS) by independent readers. Cumulative glucocorticoid doses and cessation of glucocorticoid treatment were documented in all patients.

RESULTS

We included 88 LV-GCA patients, 27 were treated with PRED, 42 with MTX and 19 with TOC. PETVAS decreased from 18.9-8.0 units at follow-up in the overall population (P <0.001). PETVAS changes were numerically higher in patients receiving MTX (-12.3 units) or TOC (-11.7 units) compared with PRED (-8.7). Mean cumulative prednisolone dosages were 5637, 4418 and 2984 mg in patients treated with PRED, MTX and TOC (P =0.002). Risk ratios for glucocorticoid discontinuation at the time of follow-up PET/CT were 6.77 (95% CI: 1.01, 45.29; P =0.049) and 16.25 (95% CI: 2.60, 101.73; P =0.003) for MTX and TOC users compared with PRED users.

CONCLUSION

Treatment of LV-GCA inhibits vascular inflammation in the aorta and its major branches. While similar control of vascular inflammation was achieved with PRED, MTX and TOC treatments, TOC showed a strong glucocorticoid sparing effect, supporting the concept of initial combination therapy.

Cul de Sac : An Unusual Presentation of Giant Cell Arteritis

Giant cell arteritis (GCA), previously referred to as temporal arteritis, continues to pose significant diagnostic challenges to clinicians as it could have unusual and atypical presentations. We present the case of a 69-year-old Caucasian male who had presented with painful scrotal swelling and bilateral arm pain and was eventually diagnosed with GCA based on histological findings. His symptoms resolved completely with the initiation of high-dose steroids. It is important to note that some clinical manifestations of GCA could be subtle, atypical, and maybe entirely extracranial. A high index of suspicion is helpful when diagnosing patients who present with non-specific or constitutional symptoms as delay in diagnosis or treatment in these patients could result in severe adverse outcomes.

Diagnosing Giant Cell Arteritis: A Comprehensive Practical Guide for the Practicing Rheumatologist

Giant cell arteritis (GCA) is the most common large vessel vasculitis in the elderly population. In recent years, advanced imaging has changed the way GCA can be diagnosed in many locations. The GCA fast-track clinic (FTC) approach combined with ultrasound (US) examination allows prompt treatment and diagnosis with high certainty. FTCs have been shown to improve prognosis while being cost effective. However, all diagnostic modalities are highly operator dependent, and in many locations expertise in advanced imaging may not be available. In this paper, we review the current evidence on GCA diagnostics and propose a simple algorithm for diagnosing GCA for use by rheumatologists not working in specialist centres.

Aortitis - An Interdisciplinary Challenge

The term 'aortitis' comprises a heterogeneous spectrum of diseases, with varied etiology and clinical presentations, whose common characteristic is the inflammation of the aortic wall. Since aortitis can mimic almost all common cardiovascular disorders, its clinical recognition remains a challenge. Some cases of aortitis remain undetected for a long time and may be diagnosed after severe life-threatening complications have already arisen. The diagnosis of aortitis is based on the presence of homogeneous circumferential thickening of the aortic wall detected on aortic imaging, or typical histological features in combination with clinical findings and laboratory parameters. Management of aortitis is usually conservative (immunosuppressive drugs in noninfectious aortitis; antimicrobial drugs in infectious). However, if vascular complications such as aortic aneurysm, rupture, or steno-occlusive events appear, aortic surgery or endovascular therapy may be required. This review article summarizes the current knowledge regarding the etiology, clinical presentation, diagnosis, and treatment of inflammatory diseases of the aorta to promote better clinical management of these entities.

Incidence and prevalence of large vessel vasculitis (giant cell arteritis and Takayasu arteritis) in northern Italy: A population-based study

OBJECTIVES

To investigate the epidemiology of the entire spectrum of large vessel vasculitis (LVV) in a well-defined population from a Northern Italian area.

METHODS

All patients with incident giant cell arteritis (GCA) diagnosed from 2005 to 2016 and all patients with incident Takayasu arteritis (TAK) diagnosed from 1998 to 2016 living in the Reggio Emilia area were identified. Only patients satisfying the modified inclusion criteria of the GiACTA trial, and the 1990 ACR classification criteria for TAK were included. The epidemiology of cranial- and LV-GCA was separately evaluated.

RESULTS

207 patients were diagnosed with GCA and 5 with TAK. 123 patients had cranial-GCA, 53 patients had LV-GCA, and the remaining 31 patients had overlapping features. The standardized annual incidence rate of GCA was 8.3 (95% CI 7.1, 9.4) per 100,000 population ages ≥50 years. The standardized annual incidence rate of cranial-GCA (6.1 [95% CI 5.1, 7.1] per 100,000 population ages ≥50 years) was double the rate of LV-GCA (3.4 [95% CI 2.7, 4.2]). The age-specific incidence rates were similar in the <70 and >90 years age groups, but they were higher in cranial-GCA than in LV-GCA in the age groups 70-79 and 80-89 years. The age- and sex-adjusted annual incidence rate of TAK was 0.5 (95% CI 0.1, 1.2) per 1,000,000 population.

CONCLUSION

Incidence of GCA is higher than previously reported by study evaluating only biopsy-proven or ACR classification criteria confirmed cases. Cranial-GCA and LV-GCA have epidemiological differences. TAK is an extremely rare disease also in Italy.

Diagnostic Approaches for Large Vessel Vasculitides

The large vessel vasculitides comprise giant cell arteritis (GCA), Takayasu arteritis (TAK), and chronic periaortitis. The diagnostic approach to these conditions involves the correct use and interpretation of clinical criteria, imaging techniques, and, in case of GCA, temporal artery biopsy. Ultrasound, magnetic resonance imaging (MRI), and computed tomography (CT) reveal a homogeneous, concentric, thickening of the arterial wall. MRI and CT may also reveal aneurysms and stenoses. 18F-Fluorodeoxyglucose (FDG)-PET shows increased FDG uptake of inflamed artery walls delineating increased metabolic activity. Ultrasound, FDG-PET, and MRI are the recommended imaging techniques in GCA and TAK. In patients with a high suspicion of GCA who present with visual disturbances, initiation of high-dose intravenous corticosteroids should not be delayed by imaging. Extracranial large vessel vasculitis may be confirmed by all three modalities, particularly by FDG-PET in case of atypical clinical pictures. In this article, we review the role of the GCA and TAK ACR classification criteria, temporal artery biopsy, conventional angiography, ultrasound, MRI, magnetic resonance angiography (MRA), CT angiography (CTA), and FDG-PET in the diagnostic approach of large vessel vasculitis.

Systemic vasculitides and the role of multitechnique imaging in the diagnosis

Vasculitis, a systemic disease characterised by inflammation of the blood vessels, remains challenging to diagnose and manage. Vessel size has been the basis for classifying systemic vasculitides. Imaging plays a vital role in diagnosing this challenging disease. This review article aims (a) to summarise up-to-date literature in this field, as well as include classification updates and (b) to review available imaging techniques, recent advances, and emphasis on imaging findings to diagnose large vessel vasculitides.

Clinical, Laboratory and Ultrasonographic Interrelations in Giant Cell Arteritis

OBJECTIVES

The diagnosis of giant cell arteritis (GCA) is based on the presence of clinical and laboratory features. Color-duplex sonography (CDS) may supplant the limited sensitivity of temporal artery biopsy. The aim of our work was to characterize clinical and laboratory findings in patients with positive CDS for GCA.

MATERIALS AND METHODS

Retrospective study of all consecutive patients of our center fulfilling American College of Rheumatology criteria for GCA who performed CDS study between 2009-2019. Data on clinical and laboratory features were compared in two groups: with and without halo sign.

RESULTS

Ninety-one patients were included. Temporal halo sign was identified in 46% of patients. Halo sign was more often present in older patients (77 ± 8 vs 73 ± 8 years, p = 0.022), associated with systemic features (58% vs 42%, p = 0.011), higher erythrocyte sedimentation rate (84 ± 26 vs 74 ± 34 mm/hour, p = 0.020), and lower hemoglobin values (10.9 ± 1.5 vs 12.1 ± 1.6 g/dL, p < 0.001). The number of patients under corticosteroids before CDS was higher in the group without halo (62% vs 33%, p = 0.005). Ischemic stroke occurred in 17 patients (19%), 76% in the vertebrobasilar territory, and stroke was associated with vertebral halo sign (p < 0.001).

CONCLUSIONS

Halo sign was present in half of our patients. Previous corticosteroids treatment decreased positive CDS findings. Systemic symptoms and laboratory findings are more notorious in halo sign subgroup of patients. Stroke cases in GCA patients disproportionally affected the posterior circulation. Ultrasonography provides information about a more pronounced systemic involvement and a higher risk of major complications.

Diagnosis and management of giant cell arteritis: Major review

Giant cell arteritis is a medical emergency because of the high risk of irreversible blindness and cerebrovascular accidents. While elevated inflammatory markers, temporal artery biopsy and modern imaging modalities are useful diagnostic aids, thorough history taking and clinical acumen still remain key elements in establishing a timely diagnosis. Glucocorticoids are the cornerstone of treatment but are associated with high relapse rates and side effects. Targeted biologic agents may open up new treatment approaches in the future.

State of the art of 18F-FDG PET/CT application in inflammation and infection: a guide for image acquisition and interpretation

AIM

The diagnosis, severity and extent of a sterile inflammation or a septic infection could be challenging since there is not one single test able to achieve an accurate diagnosis. The clinical use of 18F-fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography/computed tomography (PET/CT) imaging in the assessment of inflammation and infection is increasing worldwide. The purpose of this paper is to achieve an Italian consensus document on [¹⁸F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases, such as osteomyelitis (OM), prosthetic joint infections (PJI), infective endocarditis (IE), prosthetic valve endocarditis (PVE), cardiac implantable electronic device infections (CIEDI), systemic and cardiac sarcoidosis (SS/CS), diabetic foot (DF), fungal infections (FI), tuberculosis (TBC), fever and inflammation of unknown origin (FUO/IUO), pediatric infections (PI), inflammatory bowel diseases (IBD), spine infections (SI), vascular graft infections (VGI), large vessel vasculitis (LVV), retroperitoneal fibrosis (RF) and COVID-19 infections.

METHODS

In September 2020, the inflammatory and infectious diseases focus group (IIFG) of the Italian Association of Nuclear Medicine (AIMN) proposed to realize a procedural paper about the clinical applications of [¹⁸F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases. The project was carried out thanks to the collaboration of 13 Italian nuclear medicine centers, with a consolidate experience in this field. With the endorsement of AIMN, IIFG contacted each center, and the pediatric diseases focus group (PDFC). IIFG provided for each team involved, a draft with essential information regarding the execution of [¹⁸F]FDG PET/CT or PET/MRI scan (i.e., indications, patient preparation, standard or specific acquisition modalities, interpretation criteria, reporting methods, pitfalls and artifacts), by limiting the literature research to the last 20 years. Moreover, some clinical cases were required from each center, to underline the teaching points. Time for the collection of each report was from October to December 2020.

RESULTS

Overall, we summarized 291 scientific papers and guidelines published between 1998 and 2021. Papers were divided in several sub-topics and summarized in the following paragraphs: clinical indications, image interpretation criteria, future perspectivess and new trends (for each single disease), while patient preparation, image acquisition, possible pitfalls and reporting modalities were described afterwards. Moreover, a specific section was dedicated to pediatric and PET/MRI indications. A collection of images was described for each indication.

CONCLUSIONS

Currently, [¹⁸F]FDG PET/CT in oncology is globally accepted and standardized in main diagnostic algorithms for neoplasms. In recent years, the ever-closer collaboration among different European associations has tried to overcome the absence of a standardization also in the field of inflammation and infections. The collaboration of several nuclear medicine centers with a long experience in this field, as well as among different AIMN focus groups represents a further attempt in this direction. We hope that this document will be the basis for a "common nuclear physicians' language" throughout all the country.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40336-021-00445-w.

The utility of PET/CT in large vessel vasculitis

18F-FDG PET/CT occupies a growing role in the diagnosis of large vessel vasculitis (LVV), illustrating enhanced uptake in the lining of large vessels. A retrospective single center study was conducted of patients who underwent 18F-FDG PET/CT scans between 2009 and 2019 at Sheba Medical Center, Israel. The imaging results were analyzed for evidence of LVV. We reviewed the PET/CT scans of 126 patients and identified 57 studies that either showed evidence of active LVV or that had been performed in patients previously treated for systemic vasculitis. In 6 patients with fevers of unknown origin and elevated inflammatory markers, PET/CT revealed LVV. Six of 13 patients previously treated for systemic vasculitis demonstrated persistent large vessel uptake. LVV was identified in 8 patients with other autoimmune diseases, and in 4 diagnosed with infectious aortitis. In 26 patients who underwent malignancy surveillance, PET/CT revealed more localized large vessel wall inflammation. Our results illustrate that PET/CT may identify large vessel wall inflammation in patients with a suspicion of LVV, and incidentally in patients who undergo malignancy surveillance. PET/CT may also help delineate the presence and extent of vessel inflammation in patients with LVV and in those with other autoimmune diseases.

The Role of Multimodality Imaging in Monitoring Disease Activity and Therapeutic Response to Tocilizumab in Giant Cell Arteritis

Introduction

Giant cell arteritis (GCA) is a large vessel (LV) vasculitis, mainly affecting elder patients. Monitoring GCA activity during tocilizumab (TCZ) treatment is an unmet need, since low serum levels of C-reactive protein (CRP) during treatment may underestimate disease activity. To date, few data are available on the role of different imaging techniques in monitoring GCA activity and response to treatment. We report herein a cohort of GCA patients treated with TCZ and followed up with multimodal imaging. Patients and Methods. We collected clinical, laboratory, and imaging data of 11 GCA patients treated with TCZ 162 mg subcutaneously every week. Disease activity was assessed at baseline and within 12 months from the start of treatment using different imaging techniques such as color Doppler ultrasonography (CDUS), magnetic resonance imaging/angiography (MRI/MRA), computed tomography angiography (CTA), and/or positron emission tomography (PET).

Results

Four patients were affected by cranial and 7 by LV-GCA. All patients were treated with oral glucocorticoids (GCs) (mean dose 55.68 mg ± 8.19 of prednisone or equivalent) in combination with TCZ. Treatment was preceded in 5 cases by 3 intravenous boluses of 1000 mg methylprednisolone. A significant decrease of the mean dose of oral GCs was observed between baseline and the last follow-up visit (4.65 ± 3.69 mg) (p = 0.003). TCZ treatment significantly decreased erythrocyte sedimentation rate (p < 0.01) and CRP levels (p < 0.01). At follow-up (mean 8.18 ± 3.63 months), all patients were in clinical and serological remission. Moreover, PET, CDUS, MRI/MRA, and CTA did not show any LVV finding.

Conclusions

Our study highlights TCZ efficacy in inducing GCA remission and its steroid-sparing effect. We highlighted a reliability of imaging procedures in the evaluation of disease activity and treatment response. A close disease monitoring with imaging techniques should be taken into account in GCA patients during TCZ treatment.

Imaging for Diagnosis, Monitoring, and Outcome Prediction of Large Vessel Vasculitides

Purpose of Review

To discuss and summarize the latest evidence on imaging techniques in giant cell arteritis (GCA) and Takayasu arteritis (TAK). This is a report on the performance of ultrasound (US), magnetic resonance imaging (MRI), computed tomography (CT), 18F-fluorodeoxyglucose positron emission tomography (18-FDG-PET), and other emerging imaging techniques in diagnosis, outcome prediction, and monitoring of disease activity.

Recent Findings

Imaging techniques have gained an important role for diagnosis of large vessel vasculitides (LVV). As signs of vasculitis, US, MRI, and CT show a homogeneous arterial wall thickening, which is mostly concentric. PET displays increased FDG uptake in inflamed artery walls. US is recommended as the initial imaging modality in GCA. MRI and PET/CT may also detect vasculitis of temporal arteries. For TAK, MRI is recommended as the first imaging modality as it provides a good overview without radiation. Extracranial LVV can be confirmed by all four modalities. In addition, MRI and PET/CT provide consistent examination of the aorta and its branches. New techniques such as contrast-enhanced ultrasound, PET/MRI, and auxiliary methods such as “computer-assisted quantitative analysis” have emerged and need to be further validated.

Summary

Imaging has partly replaced histology for confirming LVV. Provided experience and adequate training, US, MRI, CT, or PET provide excellent diagnostic accuracy. Imaging results need to complement history and clinical examination. Ongoing studies are evaluating the role of imaging for monitoring and outcome measurement.

Halo score (temporal artery, its branches and axillary artery) as a diagnostic, prognostic and disease monitoring tool for Giant Cell Arteritis (GCA)

BACKGROUND

Giant cell arteritis (GCA) is a common large vessel vasculitis of the elderly, often associated with sight loss. Glucocorticoids (GC remain the mainstay of treatment, although biologic treatments have been approved. Biomarkers predicting disease severity, relapse rates and damage are lacking in GCA.EULAR recommends ultrasound (US) as the first investigation for suspected GCA. The cardinal US finding, a non-compressible halo, is currently categorised as either negative or positive. However, the extent and severity of this finding may vary.In this study, we hypothesise whether the extent and severity of the halo sign [calculated as a single composite Halo score (HS)] of temporal and axillary arteries may be of diagnostic, prognostic and monitoring importance; whether baseline HS is linked to disease outcomes, relapses and damage; whether HS can stratify GCA patients for individual treatment needs; whether HS can function as an objective monitoring tool during follow up.

METHODS

This is a prospective, observational study. Suspected GCA Participants will be selected from the GCA FTC at the participating centres in the UK. Informed consent will be obtained, and patients managed as part of standard care. Patients with GCA will have HS (temporal and axillary arteries) measured at baseline and months 1,3,6 and 12 long with routine clinical assessments, blood sampling and patient-reported outcomes (EQ5D). Non-GCA patients will be discharged back to the referral team and will have a telephone interview in 6 months.We aim to recruit 272 suspected GCA referrals which should yield 68 patients (25% of referrals) with confirmed GCA. The recruitment will be completed in 1 year with an estimated total study period of 24 months.

DISCUSSION

The identification of prognostic factors in GCA is both timely and needed. A prognostic marker, such as the HS, could help to stratify GCA patients for an appropriate treatment regimen. Tocilizumab, an IL-6R blocking agent, switches off the acute phase response (C-Reactive Protein), making it difficult to measure the disease activity. Therefore, an independent HS, and changes in that score during treatment and follow-up, maybe a more objective measure of response compare to patient-reported symptoms and clinical assessment alone.

Potential Applications of PET Scans, CT Scans, and MR Imaging in Inflammatory Diseases: Part II: Cardiopulmonary and Vascular Inflammation

Detecting inflammation is among the most important aims of medical imaging. Inflammatory process involves immune system activity and local tissue response. The role of PET with fludeoxyglucose F 18 has been expanded. Systemic vasculitides and cardiopulmonary inflammatory disorders constitute a wide range of diseases with multisystemic manifestations. PET with fludeoxyglucose F 18 is useful in their diagnosis, assessment, and follow-up. This article provides an overview of the current status and potentials of hybrid molecular imaging in evaluating cardiopulmonary and vascular inflammatory diseases focusing on the potential for PET with fludeoxyglucose F 18/MR imaging and PET/CT scans.

Imaging in Vasculitis

Purpose of Review

Vasculitides are characterized by mostly autoimmunologically induced inflammatory processes of vascular structures. They have various clinical and radiologic appearances. Early diagnosis and reliable monitoring are indispensable for adequate therapy to prevent potentially serious complications. Imaging, in addition to laboratory tests and physical examination, constitutes a key component in assessing disease extent and activity. This review presents current standards and some typical findings in the context of imaging in vasculitis with particular attention to large vessel vasculitides.

Recent Findings

Recently, imaging has gained importance in the management of vasculitis, especially regarding large vessel vasculitides (LVV). Recently, EULAR (European League Against Rheumatism) has launched its recommendations concerning the diagnosis of LVVs. Imaging is recommended as the preferred complement to clinical examination. Color-coded duplex sonography is considered the first choice imaging test in suspected giant cell arteritis, and magnetic resonance imaging is considered the first choice in suspected Takayasu’s arteritis.

Summary

Due to diversity of clinical and radiologic presentations, diagnosis and therapy monitoring of vasculitides may constitute a challenge. As a result of ongoing technological progress, a variety of non-invasive imaging modalities now play an elemental role in the interdisciplinary management of vasculitic diseases.

Update on vasculitis: an overview and dermatological clues for clinical and histopathological diagnosis - part I

The term vasculitis refers to the inflammation of vessel walls. It may range in severity from a self-limited disorder in one single organ to a life-threatening disease due to multiple organ failure. It has many causes, although they result in only a few histological patterns of vascular inflammation. Vessels of any type and in any organ can be affected, a fact that results in a broad variety of signs and symptoms. Different vasculitides with indistinguishable clinical presentations have quite different prognosis and treatments. This condition presents many challenges to physicians in terms of classification, diagnosis, appropriate laboratory workup, and treatment. Moreover, it compels a careful follow-up. This article reviews the Chapel-Hill 2012 classification, etiology, recent insights in pathophysiology, some important dermatological clues for the diagnosis and summarizes treatment of some of these complex vasculitis syndromes.

The Impact of Temporal Artery Biopsy at a UK Tertiary Plastic Surgery Unit

Guidelines recommend temporal artery biopsy (TAB) for patients suspected of having giant cell arteritis (GCA). We evaluated the impact of TAB on the diagnosis and management of patients with suspected GCA at a tertiary plastic surgery unit.

Methods

A retrospective review of all TAB procedures performed at our centre over 7 years was performed. One hundred and one patients were included in the study. Patients were classified into 3 diagnostic groups: confirmed (positive TAB), presumed (negative TAB with high clinical suspicion) and unlikely (negative TAB with low clinical suspicion). The clinical presentation and management for each group were compared.

Results

The average American College of Rheumatology (ACR) score was 3.07. The number of patients with an ACR score of ≥3 before TAB was 72 (71.3%) and remained the same after TAB. The number of patients who remained on steroid therapy was lower in the group with an unlikely diagnosis of GCA compared to the group with a confirmed diagnosis (p<0.05). Conversely, there was no significant difference in steroid therapy between those with a presumed and confirmed diagnosis (p>0.05).

Conclusions

This study found a significant difference in steroid treatment between those with confirmed GCA and those where the diagnosis was unlikely showing that TAB may support decisions regarding steroid therapy. However, TAB was inappropriately requested for patients whose pre-TAB ACR score was ≥3 as this score is sufficient for the diagnosis of GCA. Therefore, the use of TAB should be limited to cases of diagnostic uncertainty.

Vasculitis: A Checklist to Approach and Treatment Update for Dermatologists

Vasculitis poses a great diagnostic, investigative and therapeutic challenge to the treating physician. The classification of vasculitides itself still eludes universal acceptance. Comprehensive management comprises establishing the diagnosis of true vasculitis after ruling out vasculitis mimics, finding the etiology if feasible, assessing the caliber of the vessels involved, deciphering the pathological process of vessel damage, investigating for the existence and extent of systemic involvement and finally planning the therapy in the background of co-morbidities. Successful management also entails regular monitoring to foresee complications arising from the disease process itself as well as complications of immunosuppressive treatment. Although steroids remain first line drug, biologics are emerging as popular agents in the treatment of immune-mediated vasculitis. Triphasic treatment is the best plan of action comprising induction, maintenance of remission and treatment of relapses.

Magnetic resonance angiography versus 18F-fluorodeoxyglucose positron emission tomography in large vessel vasculitis

With advances in our understanding of the pathogenesis of large vessel vasculitides, we recognise the persistence of inflammation in large vessels, sometimes despite therapy to control clinical symptoms. Achieving an early diagnosis and establishing the extent of disease are important steps in improving our management of these diseases. Imaging is playing an increasing role in the assessment of these patients from diagnosis to prognosis. We review the current and potential role of two important and potentially complementary imaging techniques of magnetic resonance angiography and 18F-fluorodeoxyglucose positron emission tomography in the evaluation of patients with giant cell arteritis and Takayasu arteritis.

[Large vessel vasculitis : Giant cell arteritis and Takayasu arteritis]

According to the Chapel Hill Classification, large vessel vasculitides encompass giant cell arteritis (GCA) and the histologically related Takakaysu arteritis (TAK). The two diseases lack autoantibodies and present with a systemic inflammatory response. GCA typically shows a sudden onset with profound sickness, loss of appetite and of body weight, and temporal headache. Due to the substantial risk of sudden blindness, diagnostic work-up has to be performed immediately and treatment started without delay. A close association between polymyalgia rheumatica (PMR) and GCA is well established. Takayasu arteritis very often begins in adolescence. In contrast to GCA, the general symptoms are much less pronounced and aside from occasional carotidodynia there is a lack of diagnostic symptoms. TAK is often diagnosed in late stages due to exercise-induced claudication.

[Large-vessel vasculitis-giant cell and Takayasu arteritis]

Large-vessel vasculitis includes giant cell arteritis (GCA) and Takayasu arteritis (TA). GCA can affect persons from the age of 50 years and is more frequent among women. The disease course generally begins with an acute phase, with patients feeling very unwell and experiencing temporal headaches. Rapid diagnosis and treatment are necessary to reduce the risk of blindness. A suspected diagnosis must be confirmed by imaging, histology is optional. Initial treatment comprises oral prednisone. Recent studies have demonstrated inhibition of interleukin‑6 with tocilizumab (TCZ) to be highly effective. Alternatively, methotrexate can be administered in a steroid-sparing approach. In contrast, TA onset is generally during childhood or adolescence, and begins with moderate systemic inflammation. The aorta and its main branches are affected. Treatment comprises steroids, disease-modifying antirheumatic drugs, and the tumor necrosis factor inhibitor infliximab or TCZ.

Ultrasound imaging of the arterial system

Ultrasound (US) and Doppler are often the first imaging to be carried out for arterial disease, and with good reason. US is noninvasive, free of radiation exposure and crucial for follow up imaging. The review that follows aims to highlight the various applications of US in imaging of the arterial system.

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

AIM

To determine the diagnostic yield of ¹⁸ F-fluorodeoxyglucose positron emission tomography (PET) in disease activity assessment of large vessel vasculitides (LVV).

METHODS

Patients with LVV who had undergone PET (between 2004 and June 2010) or PET co-registered with computed tomography (PET/CT; since June 2010) were identified. Clinical disease activity was assessed using established scoring systems. PET images were reviewed by two blinded nuclear medicine physicians. Uptake of the aortic wall was compared to the liver uptake utilizing a visual 4-point score, with a vessel wall uptake similar or higher than liver uptake considered as active disease. Various target-to-background ratios were calculated. Receiver operator characteristics analysis was applied to determine the diagnostic accuracy of PET for detecting clinically active disease. Interobserver agreement of visual readings was measured with Cohen´s kappa.

RESULTS

Eighty examinations in 62 patients were analyzed, with a mean time between diagnosis and PET of 106 ± 171 weeks. Fifty-seven cases were finally classified as clinically active and 23 cases as clinically inactive. With a cut-off value of 1.3, the aorta-to-liver ratio yielded a sensitivity and specificity of 84.2% and 82.6% (area under the curve 0.9). Overall, sensitivity and specificity of visual analysis were 68.4% and 91.3%, but sensitivity decreased to 54% in patients treated for more than 3 months. Interobserver agreement of visual rating was excellent (κ: 0.93).

CONCLUSION

Positron emission tomography is specific and reliable in disease activity assessment of LVV, but lacks sensitivity for detecting active disease in patients under long-term immunosuppressive treatment.

Giant cell arteritis presenting as bilateral anterior ischemic optic neuropathy: a biopsy-proven case report in Chinese patient

Background

Giant cell arteritis (GCA) is a systemic vasculitis of medium and large-size vessels and can led to permanent visual loss in elderly patients. GCA is very rare among Asians. We report a Chinese patient presenting with acute bilateral anterior ischemic optic neuropathy, and the temporal artery biopsy proved the diagnose of GCA.

Case presentation

A 77-year-old Chinese man presented with sudden bilateral blindness for 5 days with a severe headache. Funduscopic examination revealed bilateral optic disc swollen with “chalky white” pallid appearance. The blood tests showed the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) elevated dramatically. The color duplex ultrasonography (CDUS) of the superficial temporal artery revealed the inflammation of the vessel wall as a “halo sign”. The temporal artery biopsy was perfumed and the pathology revealed luminal occlusion with multinuclear giant cell infiltration. The patient was treated with intravenous methylprednisolone for 3 days and oral prednisone weaning for 12 months. The visual acuity remained no light perception at one year follow-up.

Conclusions

Although very rare in Asian, GCA can led to permanent blindness in elderly Chinese caused by anterior ischemic optic neuropathy. The noninvasive CDUS might be a promising technique for diagnose GCA in highly suspected patients.

Aortic dilatation in patients with large vessel vasculitis: A longitudinal case control study using PET/CT

OBJECTIVE

To evaluate aortic diameter and predictors of aortic dilatation using ¹⁸FDG-PET/CT in a longitudinally followed cohort of patients with large vessel vasculitis (LVV) compared with controls.

METHODS

All consecutive patients with LVV who underwent at least 2 PET/CT scans between January 2008 and May 2015 were included. The first and last PET/CT study was evaluated by a radiologist and a nuclear medicine physician. Diameter and FDG uptake of the aorta was measured at 4 different levels: ascending, descending thoracic, suprarenal and infrarenal abdominal aorta. Twenty-nine age- and sex-matched patients with lymphoma who underwent at least 2 PET/CT scans in the same time interval were selected as controls.

RESULTS

93 patients with LVV were included in the study. In the time interval between first and last PET/CT study (median time 31 months), the diameter of the ascending, descending thoracic and suprarenal abdominal aorta significantly increased in LVV patients but not in controls. At last PET/CT, patients with LVV compared with controls had higher diameter of ascending [35.41 (5.54) vs 32.97 (4.11) mm, p = 0.029], descending thoracic [28.42 (4.82) vs 25.72 (3.55) mm, p = 0.007] and suprarenal abdominal aorta, mean [25.34 (7.01) vs 22.16 (3.26) mm, p = 0.005] and more frequently had aortic dilatation [19% vs 3%, p = 0.023]. Significant predictors of aortic dilatation were male sex [OR 7.27, p = 0.001] and, only for GCA, hypertension [OR 6.30, p = 0.031]. Finally, GCA patients with aortic FDG uptake grade 3 at first PET/CT, compared to those with aortic FDG uptake ≤2, had significantly higher aortic diameter.

CONCLUSIONS

Patients with LVV are at increased risk of aortic dilatation compared with age- and sex-matched controls. Significant predictors of aortic dilatation are male sex and, only for GCA, hypertension. GCA patients with aortic FDG uptake grade 3 are at increased risk of aortic dilatation.

Investigations in systemic vasculitis - The role of imaging

Imaging plays an increasing role for confirming a suspected diagnosis of giant cell arteritis (GCA) or Takayasu arteritis (TAK). Ultrasound, magnetic resonance imaging (MRI), and computed tomography demonstrate a homogeneous, most commonly concentric, arterial wall thickening. 18F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) displays increased FDG uptake of inflamed artery walls delineating increased metabolism. Ultrasound and MRI are recommended to be the initial imaging modalities in cranial GCA and TAK, respectively. Extracranial disease can be confirmed by all four modalities, particularly by PET in case of inflammation of unknown origin. If the diagnosis remains uncertain, additional investigations including biopsy and/or additional imaging are recommended. Imaging should be performed by a trained specialist using appropriate operational procedures and settings with appropriate equipment. Further research is necessary on the role of imaging for disease monitoring. This review will discuss advantages and disadvantages of imaging modalities in the diagnosis of vasculitis.

Diagnosis and differential diagnosis of large-vessel vasculitides

There are no universally accepted diagnostic criteria for large-vessel vasculitides (LVV), including giant cell arteritis (GCA) and Takayasu arteritis (TAK). Currently, available classification criteria cannot be used for the diagnosis of GCA and TAK. Early diagnosis of these two diseases is quite challenging in clinical practice and may be accomplished only by combining the patient symptoms, physical examination findings, blood test results, imaging findings, and biopsy results, if available. Awareness of red flags which lead the clinician to investigate TAK in a young patient with persistent systemic inflammation is helpful for the early diagnosis. It should be noted that clinical presentation may be highly variable in a subgroup of GCA patients with predominant large-vessel involvement (LVI) and without prominent cranial symptoms. Imaging modalities are especially helpful for the diagnosis of this subgroup. Differential diagnosis between older patients with TAK and this subgroup of GCA patients presenting with LVI may be difficult. Various pathologies may mimic LVV either by causing systemic inflammation and constitutional symptoms, or by causing lumen narrowing with or without aneurysm formation in the aorta and its branches. Differential diagnosis of aortitis is crucial. Infectious aortitis including mycotic aneurysms due to septicemia or endocarditis, as well as causes such as syphilis and mycobacterial infections should always be excluded. On the other hand, the presence of non-infectious aortitis is not unique for TAK and GCA. It should be noted that aortitis, other large-vessel involvement or both, may occasionally be seen in various other autoimmune pathologies including ANCA-positive vasculitides, Behçet's disease, ankylosing spondylitis, sarcoidosis, and Sjögren's syndrome. Besides, aortitis may be idiopathic and isolated. Atherosclerosis should always be considered in the differential diagnosis of LVV. Other pathologies which may mimic LVV include, but not limited to, congenital causes of aortic coarctation and middle aortic syndrome, immunoglobulin G4-related disease, and hereditary disorders of connective tissue such as Marfan syndrome and Ehler-Danlos syndrome.

Unmet Needs in the Pathogenesis and Treatment of Vasculitides

Despite the progress in the last years on the field of vasculitides, there are several unmet needs regarding classification, disease activity assessment, predictors of flares and complications, and type of treatment for the different forms. The 1990 American College of Rheumatology (ACR) classification criteria currently used to define giant cell arteritis and Takayasu arteritis were designed to discriminate between different types of vasculitides but not to differentiate vasculitis from other disorders. Recently, efforts have been made to overcome the shortcomings of the ACR criteria. The lack of an accepted definition of disease activity in large-vessel vasculitides presents a major challenge in creating useful and valid outcome tools for the assessment of disease course. Identification of predictors of flares can aid in optimizing therapeutic strategies, minimizing disease flares, and reducing treatment-related side effects. It is furthermore important to recognize and characterize the risk factor that might predict the manifestations associated with poor outcome and prognosis. Two RCTs have evidenced the efficacy of tocilizumab in addition to glucocorticoids (GCs) in the treatment of giant cell arteritis (GCA). However, the role of tocilizumab or other biological agents without GCs needs to be investigated. Recent observational studies have suggested that rituximab is also effective in patients with eosinophilic granulomatosis with polyangiitis and in antineutrophil cytoplasmic antibodies (ANCA)-negative patients with granulomatosis with polyangiitis and microscopic polyangiitis. Rituximab or anti-TNF alfa may represent a possible alternative therapy in case of refractory or difficult to treat polyarteritis nodosa (PAN) patients. The new International Criteria for Behçet's Disease have shown a better sensitivity and a better accuracy compared to the older International Study Group on Behçet's Disease criteria. The EULAR recommendations for the management of Behçet's disease (BD) have been recently updated. However, the treatment of refractory disease is still a real challenge.

Ultrasound in the diagnosis and management of giant cell arteritis

US has become an important diagnostic tool for musculoskeletal diseases. Because of its wide availability in rheumatology practice, US has also been applied in other rheumatic diseases such as GCA. In acute GCA, US displays a non-compressible, hypoechoic, most commonly concentric arterial wall thickening. Temporal and axillary arteries should be examined in patients with suspected GCA and PMR. Additionally, almost all other large arteries, with the exception of the thoracic aorta, can be easily delineated by US. Many studies and several meta-analyses have been conducted to evaluate the diagnostic performance of US. US is more sensitive than temporal artery biopsy (TAB) because TAB evaluates only a limited anatomical region in a systemic disease. Most US studies arrive at specificities between 90 and 100% compared with the final clinical diagnosis. Reliability for reading US images and videos is excellent and comparable to reliability for reading TAB specimens. The advantage of US over other imaging techniques in GCA is its availability, safety and tolerability and its high resolution of 0.1 mm. Rheumatology departments are increasingly establishing fast-track clinics. Physicians can refer patients with suspected GCA within 24 h. Patients receive clinical and US examination by experienced specialists, establishing a clear diagnosis either before TAB or without the need for TAB. The introduction of fast-track clinics has led to a significant reduction of permanent vision loss. Furthermore, a process that primarily includes US is significantly more cost-effective than TAB.

Assessing Vasculitis in Giant Cell Arteritis by Ultrasound: Results of OMERACT Patient-based Reliability Exercises

Objective.

To test the reliability of Outcome Measures in Rheumatology Clinical Trials (OMERACT) consensus-based ultrasound definitions for normal and vasculitic temporal and axillary arteries in patients with giant cell arteritis (GCA) and in controls.

Methods.

A preliminary 1-day meeting and a full 3-day meeting fulfilling OMERACT Ultrasound Group guidelines were held. Temporal and axillary arteries were examined at 2 timepoints by 12 sonographers on 4 patients with GCA and 2 controls. The aim was to test inter- and intrareader reliability for normal findings, halo sign, and compression sign. In both meetings, patients had established GCA. Pathology was more recent in the full meeting, which was preceded by 6 h of training. Scanning time was 15–20 min instead of 10–13 min.

Results.

In the preliminary exercise, interreader reliabilities were fair to moderate for the overall diagnosis of GCA (Light κ 0.29–0.51), and poor to fair for identifying vasculitis in the respective anatomical segments (Light κ 0.02–0.46). Intrareader reliabilities were moderate (Cohen κ 0.32–0.64). In the main exercise, interreader reliability was good to excellent (Light κ 0.76–0.86) for the overall diagnosis of GCA, and moderate to good (Light κ 0.46–0.71) for identifying vasculitis in the respective anatomical segments. Intrareader reliability was excellent for diagnosis of GCA (Cohen κ 0.91) and good (Cohen κ 0.71–0.80) for the anatomical segments.

Conclusion.

OMERACT-derived definitions of halo and compression signs of temporal and axillary arteries are reliable in recent-onset GCA if experienced sonographers (> 300 examinations) have 15–20 min for a standardized examination with prior training and apply > 15 MHz probes.

Giant cell arteritis: beyond temporal artery biopsy and steroids

Giant cell arteritis is the most common primary vasculitis of the elderly. The acute complications of untreated giant cell arteritis, such as vision loss or occasionally stroke, can be devastating. The diagnosis is, however, not altogether straightforward due to variable sensitivities of the temporal artery biopsy as a reference diagnostic test. In this review, we discuss the increasing role of imaging in the diagnosis of giant cell arteritis. Glucocorticoid treatment is the backbone of therapy, but it is associated with significant adverse effects. A less toxic alternative is required. Conventional and novel immunosuppressive agents have only demonstrated modest effects in a subgroup of steroid refractory Giant cell arteritis due to the different arms of the immune system at play. However, recently a study of interleukin-6 blockade demonstrated benefits of giant cell arteritis. The current status of these immunosuppressive agents and novel therapies are also discussed in this review.

Definitions and reliability assessment of elementary ultrasound lesions in giant cell arteritis: a study from the OMERACT Large Vessel Vasculitis Ultrasound Working Group

Objectives

To define the elementary ultrasound (US) lesions in giant cell arteritis (GCA) and to evaluate the reliability of the assessment of US lesions according to these definitions in a web-based reliability exercise.

Methods

Potential definitions of normal and abnormal US findings of temporal and extracranial large arteries were retrieved by a systematic literature review. As a subsequent step, a structured Delphi exercise was conducted involving an expert panel of the Outcome Measures in Rheumatology (OMERACT) US Large Vessel Vasculitis Group to agree definitions of normal US appearance and key elementary US lesions of vasculitis of temporal and extracranial large arteries. The reliability of these definitions on normal and abnormal blood vessels was tested on 150 still images and videos in a web-based reliability exercise.

Results

Twenty-four experts participated in both Delphi rounds. From originally 25 statements, nine definitions were obtained for normal appearance, vasculitis and arteriosclerosis of cranial and extracranial vessels. The ‘halo’ and ‘compression’ signs were the key US lesions in GCA. The reliability of the definitions for normal temporal and axillary arteries, the ‘halo’ sign and the ‘compression’ sign was excellent with inter-rater agreements of 91–99% and mean kappa values of 0.83–0.98 for both inter-rater and intra-rater reliabilities of all 25 experts.

Conclusions

The ‘halo’ and the ‘compression’ signs are regarded as the most important US abnormalities for GCA. The inter-rater and intra-rater agreement of the new OMERACT definitions for US lesions in GCA was excellent.

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.

Diagnosis and management of giant cell arteritis: an Asia-Pacific perspective

Giant cell arteritis is the commonest primary vasculitis of the elderly. However, the prevalence does vary widely between populations with highest incidence amongst Northern Europeans and lowest amongst East Asians. Preliminary studies suggest that clinical manifestations may differ between different populations. Newer diagnostic approaches including ultrasound, MR angiography and PET imaging are under review. While there have been recent advances in the diagnosis of GCA particularly with regard to imaging, there is an urgent need for improvements in methods of diagnosis, treatment and requirement for screening. Glucocorticoid treatment remain the backbone of therapy. However, glucocorticoid therapy is associated with significant adverse effects. Conventional and novel immunosuppressive agents have only demonstrated modest effects in a subgroup of steroid refractory GCA due to the different arms of the immune system at play. However, recently a study of IL-6 blockade demonstrated benefit in GCA. Newer approaches such as fast-track pathways can also result in improvements in consequences of GCA including blindness.

Takayasu arteritis and giant cell arteritis: are they a spectrum of the same disease?

Giant cell arteritis (GCA) and Takayasu arteritis (TAK) are forms of large-vessel vasculitides that affect the aorta and its branches. There is ongoing debate about whether they are within a spectrum of the same disease or different diseases. Shared commonalities include clinical features, evidence of systemic inflammation, granulomatous inflammation on biopsy, role of T-helper (Th)-1 and Th17 in the pathogenesis, and, abnormalities of the aorta and its branches on imaging. However, there are also several differences in the geographic distribution, genetics, inflammatory cells and responses to treatment. This review highlights the similarities and differences in the epidemiology, pathogenesis, clinical manifestations, imaging findings and treatment responses in these conditions. Current data supports that they are two distinct conditions despite the numerous similarities.

Tocilizumab in Giant Cell Arteritis: A Real-Life Retrospective Study

This study aims to evaluate (1) the efficacy and safety of tocilizumab (TCZ) as a steroid-sparing agent in patients with giant cell arteritis (GCA) and (2) the usefulness of ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) in the follow-up and to detect disease activity. We retrospectively evaluated 12 patients with GCA treated with TCZ (8 mg/kg/mo). Pre- and posttherapy data about clinical signs and symptoms, laboratory results, FDG-PET imaging study, and the mean glucocorticoid (GC) dose were used to assess disease activity. Tocilizumab achieved complete disease remission in all patients. Mean FDG-PET-detected standard uptake value decreased from 2.05 ± 0.64 to 1.78 ± 0.45 ( P = .005). In 2 patients in whom temporal arteries color Doppler sonography examination was consistent with temporal arteritis, the hypoechoic halo disappeared after TCZ treatment. Mean GC dose was tapered from 26.6 ± 13.4 mg/d to 3.3 ± 3.1 mg/d ( P < .0001). One-half of the patients discontinued GC therapy. Three patients experienced severe adverse reactions and had to stop TCZ therapy. In accordance with previous reports, TCZ is an effective steroid-sparing agent for GCA, although careful monitoring of adverse drug reactions is needed. ¹⁸F-fluorodeoxyglucose positron emission tomography could be used to monitor disease activity in TCZ-treated patients, but prospective studies are needed to confirm these data.