Incidence of temporal arteritis in patients with polymyalgia rheumatica: a prospective study using colour Doppler ultrasonography of the temporal arteries

Should all patients with polymyalgia rheumatica have a vascular ultrasound assessment?

There is a growing appreciation that both giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are closely interrelated conditions that have significant overlap in aetiology, clinical characteristics and treatment regimens. Subclinical GCA in PMR is becoming increasingly recognised, and there is evolving evidence that this may be a more aggressive disease phenotype than PMR. Ultrasound (US) lends itself well as a screening tool for GCA in PMR; it is inexpensive, non-invasive, widely available, lacks ionising radiation, may be performed at the bedside and is recommended by EULAR as a first-line investigation for suspected GCA. There is insufficient evidence to currently recommend that all patients with PMR should have a US assessment for vascular involvement. However, as clinical and laboratory parameters alone do not accurately diagnose patients with subclinical GCA, we suggest that vascular US will be increasingly performed by rheumatologists in practice to identify these patients with PMR, preferably as part of larger prospective outcome studies.

Review of phase 2/3 trials in polymyalgia rheumatica and giant cell arteritis

INTRODUCTION

GCA (giant cell arteritis) and PMR (polymyalgia rheumatica) are two overlapping inflammatory rheumatic conditions that are seen exclusively in older adults, sharing some common features. GCA is a clinical syndrome characterized by inflammation of the medium and large arteries, with both cranial and extracranial symptoms. PMR is a clinical syndrome characterized by stiffness in the neck, shoulder, and pelvic girdle muscles. Both are associated with constitutional symptoms.

AREAS COVERED

In this review, we assess the established and upcoming treatments for GCA and PMR. We review the current treatment landscape, completed trials, and upcoming trials in these conditions, to identify new and promising therapies.

EXPERT OPINION

Early use of glucocorticoids (GC) remains integral to the immediate management of PMR and GCA but being aware of patient co-morbidities that may influence treatment toxicity is paramount. As such GC sparing agents are required in the treatment of PMR. Currently there are limited treatment options available for PMR and GCA, and significant unmet needs remain. Newer mechanisms of action, and hence therapeutic options being studied include CD4 T cell co-stimulation blockade, IL-17 inhibition, IL-12/23 inhibition, GM-CSF inhibition, IL-1β inhibition, TNF-α antagonist and Jak inhibition, among others, which will be discussed in this review.

Halo sign on temporal artery ultrasound versus temporal artery biopsy for giant cell arteritis

BACKGROUND

Giant cell arteritis (GCA) is a systemic, inflammatory vasculitis primarily affecting people over the age of 50 years. GCA is treated as a medical emergency due to the potential for sudden, irreversible visual loss. Temporal artery biopsy (TAB) is one of the five criteria of the American College of Rheumatology (ACR) 1990 classification, which is used to aid the diagnosis of GCA. TAB is an invasive test, and it can be slow to obtain a result due to delays in performing the procedure and the time taken for histopathologic assessment. Temporal artery ultrasonography (US) has been demonstrated to show findings in people with GCA such as the halo sign (a hypoechoic circumferential wall thickening due to oedema), stenosis or occlusion that can help to confirm a diagnosis more swiftly and less invasively, but requiring more subjective interpretation. This review will help to determine the role of these investigations in clinical practice.

OBJECTIVES

To evaluate the sensitivity and specificity of the halo sign on temporal artery US, using the ACR 1990 classification as a reference standard, to investigate whether US could be used as triage for TAB. To compare the accuracy of US with TAB in the subset of paired studies that have obtained both tests on the same patients, to investigate whether it could replace TAB as one of the criteria in the ACR 1990 classification.

SEARCH METHODS

We used standard Cochrane search methods for diagnostic accuracy. The date of the search was 13 September 2022.

SELECTION CRITERIA

We included all participants with clinically suspected GCA who were investigated for the presence of the halo sign on temporal artery US, using the ACR 1990 criteria as a reference standard. We included studies with participants with a prior diagnosis of polymyalgia rheumatica. We excluded studies if participants had had two or more weeks of steroid treatment prior to the investigations. We also included any comparative test accuracy studies of the halo sign on temporal artery US versus TAB, with use of the 1990 ACR diagnostic criteria as a reference standard. Although we have chosen to use this classification for the purpose of the meta-analysis, we accept that it incorporates unavoidable incorporation bias, as TAB is itself one of the five criteria. This increases the specificity of TAB, making it difficult to compare with US. We excluded case-control studies, as they overestimate accuracy, as well as case series in which all participants had a prior diagnosis of GCA, as they can only address sensitivity and not specificity.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the studies for inclusion in the review. They extracted data using a standardised data collection form and employed the QUADAS-2 tool to assess methodological quality. As not enough studies reported data at our prespecified halo threshold of 0.3 mm, we fitted hierarchical summary receiver operating characteristic (ROC) models to estimate US sensitivity and also to compare US with TAB. We graded the certainty of the evidence using the GRADE approach.

MAIN RESULTS

Temporal artery ultrasound was investigated in 15 studies (617 participants with GCA out of 1479, 41.7%), with sample sizes ranging from 20 to 381 participants (median 69). There was wide variation in sensitivity with a median value of 0.78 (interquartile range (IQR) 0.45 to 0.83; range 0.03 to 1.00), while specificity was fair to good in most studies with a median value of 0.91 (IQR 0.78 to 1.00; range 0.40 to 1.00) and four studies with a specificity of 1.00. The hierarchical summary receiver operating characteristic (HSROC) estimate of sensitivity (95% confidence interval (CI)) at the high specificity of 0.95 was 0.51 (0.21 to 0.81), and 0.84 (0.58 to 0.95) at 0.80 specificity. We considered the evidence on sensitivity and specificity as of very low certainty due to risk of bias (-1), imprecision (-1), and inconsistency (-1). Only four studies reported data at a halo cut-off > 0.3 mm, finding the following sensitivities and specificities (95% CI): 0.80 (0.56 to 0.94) and 0.94 (0.81 to 0.99) in 55 participants; 0.10 (0.00 to 0.45) and 1.00 (0.84 to 1.00) in 31 participants; 0.73 (0.54 to 0.88) and 1.00 (0.93 to 1.00) in 82 participants; 0.83 (0.63 to 0.95) and 0.72 (0.64 to 0.79) in 182 participants. Data on a direct comparison of temporal artery US with biopsy were obtained from 11 studies (808 participants; 460 with GCA, 56.9%). The sensitivity of US ranged between 0.03 and 1.00 with a median of 0.75, while that of TAB ranged between 0.33 and 0.92 with a median of 0.73. The specificity was 1.00 in four studies for US and in seven for TAB. At high specificity (0.95), the sensitivity of US and TAB were 0.50 (95% CI 0.24 to 0.76) versus 0.80 (95% CI 0.57 to 0.93), respectively, and at low specificity (0.80) they were 0.73 (95% CI 0.49 to 0.88) versus 0.92 (95% CI 0.69 to 0.98). We considered the comparative evidence on the sensitivity of US versus TAB to be of very low certainty because specificity was overestimated for TAB since it is one of the criteria used in the reference standard (-1), together with downgrade due to risk of bias (-1), imprecision (-1), and inconsistency (-1) for both sensitivity and specificity.

AUTHORS' CONCLUSIONS

There is limited published evidence on the accuracy of temporal artery US for detecting GCA. Ultrasound seems to be moderately sensitive when the specificity is good, but data were heterogeneous across studies and either did not use the same halo thickness threshold or did not report it. We can draw no conclusions from accuracy studies on whether US can replace TAB for diagnosing GCA given the very low certainty of the evidence. Future research could consider using the 2016 revision of the ACR criteria as a reference standard, which will limit incorporation bias of TAB into the reference standard.

Giant Cell Arteritis: Advances in Understanding Pathogenesis and Implications for Clinical Practice

Giant cell arteritis (GCA) is a noninfectious granulomatous vasculitis of unknown etiology affecting individuals older than 50 years. Two forms of GCA have been identified: a cranial form involving the medium-caliber temporal artery causing temporal arteritis (TA) and an extracranial form involving the large vessels, mainly the thoracic aorta and its branches. GCA generally affects individuals with a genetic predisposition, but several epigenetic (micro)environmental factors are often critical for the onset of this vasculitis. A key role in the pathogenesis of GCA is played by cells of both the innate and adaptive immune systems, which contribute to the formation of granulomas that may include giant cells, a hallmark of the disease, and arterial tertiary follicular organs. Cells of the vessel wall cells, including vascular smooth muscle cells (VSMCs) and endothelial cells, actively contribute to vascular remodeling responsible for vascular stenosis and ischemic complications. This review will discuss new insights into the molecular and cellular pathogenetic mechanisms of GCA, as well as the implications of these findings for the development of new diagnostic biomarkers and targeted drugs that could hopefully replace glucocorticoids (GCs), still the backbone of therapy for this vasculitis.

Prevalence and characteristics of subclinical giant cell arteritis in polymyalgia rheumatica

OBJECTIVE

The main objective of this study was to analyse the prevalence and characteristics of subclinical GCA in patients with PMR.

METHODS

This was a cross-sectional multicentre international study of consecutive patients with newly diagnosed PMR without symptoms or signs suggestive of GCA. All patients underwent US of the temporal superficial, common carotid, subclavian and axillary arteries. Patients with halo signs in at least one examined artery were considered to have subclinical GCA. The clinical, demographic and laboratory characteristics of the PMR group without subclinical vasculitis were compared with subclinical GCA, and the pattern of vessel involvement was compared with that of a classical single-centre GCA cohort.

RESULTS

We included 346 PMR patients, 267 (77.2%) without subclinical GCA and 79 (22.8%) with subclinical GCA. The PMR patients with subclinical GCA were significantly older, had a longer duration of morning stiffness and more frequently reported hip pain than PMR without subclinical GCA. PMR with subclinical GCA showed a predominant extracranial large vessel pattern of vasculitic involvement compared with classical GCA, where the cranial phenotype predominated. The patients with PMR in the classical GCA group showed a pattern of vessel involvement similar to classical GCA without PMR but different from PMR with subclinical involvement.

CONCLUSION

More than a fifth of the pure PMR patients had US findings consistent with subclinical GCA. This specific subset of patients showed a predilection for extracranial artery involvement. The optimal screening strategy to assess the presence of vasculitis in PMR remains to be determined.

Early referral of patients with suspected polymyalgia rheumatica - A systematic review

INTRODUCTION

Prompt diagnosis and treatment of polymyalgia rheumatica (PMR) is crucial to prevent long-term complications and improve patient outcomes. However, there is currently no standardized approach to referral of suspected PMR patients to rheumatologists, leading to inconsistent management practices. The objective of this systematic review was to clarify the existing evidence regarding the following aspects of early management strategies in patients with suspected PMR: diagnostic strategies, GCA screening, glucocorticoid initiation prior to referral, value of shared care and value of fast track clinic.

METHODS

Two authors performed a systematic literature search, data extraction and risk of bias assessment independently. The literature search was conducted in Embase, MEDLINE (PubMed) and Cochrane. Studies were included if they contained cohorts of suspected PMR patients and evaluated the efficacy of different diagnostic strategies for PMR, screening for giant cell arteritis (GCA), starting glucocorticoids before referral to secondary care, shared care, or fast-track clinics.

RESULTS

From 2,437 records excluding duplicates, 14 studies met the inclusion criteria. Among these, 10 studies investigated the diagnostic accuracy of various diagnostic strategies with the majority evaluating different clinical approaches, but none of them showed consistently high performance. However, 4 studies on shared care and fast-track clinics showed promising results, including reduced hospitalization rates, lower starting doses of glucocorticoids, and faster PMR diagnosis.

CONCLUSION

This review emphasizes the sparse evidence of early management and referral strategies for patients with suspected PMR. Additionally, screening and diagnostic strategies for differentiating PMR from other diseases, including concurrent GCA, require clarification. Fast-track clinics may have potential to aid patients with PMR in the future, but studies will be needed to determine the appropriate pre-referral work-up.

Polymyalgia rheumatica

Polymyalgia rheumatica is an inflammatory disease producing pain and stiffness, mainly in the shoulders and pelvic girdle, in people older than 50 years. Elevation of acute phase reactants is common due to the inflammatory nature of the disease. Since there are no specific diagnostic tests, diagnosis requires the exclusion of other diseases with similar presentations. Imaging has helped to identify the pathological substrate of polymyalgia rheumatica and it is increasingly used to support clinical diagnosis or to detect coexistent giant cell arteritis. Although polymyalgia rheumatica does not clearly impair survival or organ function, it can have a detrimental effect on quality of life. Glucocorticoids at 12·5-25·0 mg prednisone per day are effective in inducing remission in most individuals but, when tapered, relapses occur in 40-60% of those affected and side-effects are common. Assessment of disease activity can be difficult because pain related to common comorbidities such as osteoarthritis and tendinopathies, can return when glucocorticoids are reduced, and acute phase reactants are increased less during flares in individuals undergoing treatment or might increase for other reasons. The role of imaging in assessing disease activity is not yet completely defined. In the search for more efficient and safer therapies, tocilizumab and sarilumab have shown efficacy in randomised controlled trials and additional targeted therapies are emerging. However, judicious risk-benefit balance is essential in applying therapeutic innovations to people with polymyalgia rheumatica.

Disease stratification in GCA and PMR: state of the art and future perspectives

Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are closely related conditions characterized by systemic inflammation, a predominant IL-6 signature, an excellent response to glucocorticoids, a tendency to a chronic and relapsing course, and older age of the affected population. This Review highlights the emerging view that these diseases should be approached as linked conditions, unified under the term GCA-PMR spectrum disease (GPSD). In addition, GCA and PMR should be seen as non-monolithic conditions, with different risks of developing acute ischaemic complications and chronic vascular and tissue damage, different responses to available therapies and disparate relapse rates. A comprehensive stratification strategy for GPSD, guided by clinical findings, imaging and laboratory data, facilitates appropriate therapy and cost-effective use of health-economic resources. Patients presenting with predominant cranial symptoms and vascular involvement, who usually have a borderline elevation of inflammatory markers, are at an increased risk of sight loss in early disease but have fewer relapses in the long term, whereas the opposite is observed in patients with predominant large-vessel vasculitis. How the involvement of peripheral joint structures affects disease outcomes remains uncertain and understudied. In the future, all cases of new-onset GPSD should undergo early disease stratification, with their management adapted accordingly.

Vascular ultrasound in rheumatology practice

Rheumatologists are increasingly using vascular ultrasound. Several guidelines now recommend ultrasound as the first diagnostic modality in giant cell arteritis (GCA). The German curriculum for rheumatology training has recently included ultrasound for the acute diagnosis of vasculitis. Recent studies have shown that ultrasound of temporal, axillary, subclavian, and vertebral arteries has sensitivities and specificities of >90%. Vascular ultrasound detects subclinical GCA in approximately 20% of patients with "pure" polymyalgia rheumatica. GCA fast-track clinics might regularly include these patients. A new score based on the intima-media thickness of the temporal and axillary arteries allows the monitoring of structural changes with treatment. The score decreases faster for the temporal arteries than it does for the axillary arteries. Measuring the diameter of the ascending aorta and the aortic arch might become a fast and cost-effective tool for the long-term monitoring of aortic aneurysms in extracranial GCA. Vascular ultrasound also has a role for Takayasu arteritis, thrombosis, Behçet's syndrome, and Raynaud's phenomenon.

Imaging methods in polymyalgia rheumatica: a systematic review

Polymyalgia rheumatica (PMR) is an inflammatory joint disease in patients over 50 years of age with pain and prolonged morning stiffness in the shoulder and hip girdles and neck. The lack of specific clinical findings, laboratory signs, biomarker and established imaging methods makes it difficult to diagnose patients with this disease. The aim of the systematic review is to present the literature data on the use of imaging methods for early diagnosis, assessment of disease activity and therapeutic response in PMR. At the same time, the advantages, disadvantages and contraindications of each method are considered. A literature search was carried out in PubMed and Scopus up to June 2022. Studies were selected that met the following criteria: (1) English language publications in peer-reviewed journals, (2) cohort or case-control studies and a series of more than five clinical cases, (3) studies of newly diagnosed or suspected PMR patients according to classification criteria or expert opinion, (4) imaging evaluation of articular, extraarticular and vascular impairment in PMR. Out of a total of 1431 publications, 61 articles were selected, which differed in the imaging techniques used: radiography (5), scintigraphy (4), magnetic resonance imaging (14), PET/CT (14) and ultrasound (24). Prevalence of extraarticular involvement (tendons, entheses and bursae) was identified in patients with PMR. In a significant number of cases, subclinical vasculitis of the large vessels was found, confirming the common pathogenetic pathways of the two diseases. The diagnostic, therapeutic and prognostic potential of imaging methods in PMR has been relatively poorly studied and remains to be clarified.

Prevalence and characteristics of giant cell arteritis in patients with newly diagnosed polymyalgia rheumatica - a prospective cohort study

Background

It is known that giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) often occur together. So far, the prevalence of GCA in newly diagnosed PMR patients has not been evaluated in a prospective ultrasound study.

Objective

The aim of this study was to assess the prevalence of GCA using vascular ultrasound in patients with newly diagnosed PMR.

Design

A consecutive cohort of newly diagnosed PMR patients was prospectively evaluated for the presence of GCA with the use of systematic musculoskeletal and vascular ultrasound examination.

Methods

Overall, 60 patients with newly diagnosed PMR were prospectively enrolled. Symptoms and laboratory findings were collected. All patients underwent ultrasound of shoulder and hip joints, and vascular ultrasound evaluating the facial, temporal, carotid, vertebral and axillary arteries. Patients were diagnosed with GCA if they had ultrasound imaging findings of GCA. Patients with PMR (PMR-group) and patients with PMR and GCA (PMR-GCA-group) were compared, and a C-reactive protein (CRP) cut-off value was evaluated.

Results

GCA was diagnosed in 28 of 60 PMR patients (46%). The PMR-group consisted of 20 (62.5%) females with a mean age of 69 (±9.9) years, while the PMR-GCA-group consisted of 11 (39.3%) females with a mean age of 74 (±8.4) years. In 13 of 28 patients (46%) in the PMR-GCA-group, GCA was subclinical and only diagnosed by ultrasound. The PMR-GCA-group showed higher values of joint effusion and significantly higher CRP values. A CRP cut-off value of 26.5 mg/litre (reference range 0-5 mg/litre) yielded a sensitivity of 66% with a specificity of 73% for GCA.

Conclusion

GCA was found in 46% of newly diagnosed PMR patients; 22% of the patients with PMR had asymptomatic GCA. Joint effusions were higher in the PMR-GCA-group, with significant results for the hip joint. A CRP cut-off value of ⩾26.5 mg/litre in PMR can help in the identification of subclinical GCA.

Predictive Factors of Giant Cell Arteritis in Polymyalgia Rheumatica Patients

Polymyalgia rheumatica (PMR) is an inflammatory rheumatism of the shoulder and pelvic girdles. In 16 to 21% of cases, PMR is associated with giant cell arteritis (GCA) that can lead to severe vascular complications. Ruling out GCA in patients with PMR is currently a critical challenge for clinicians. Two GCA phenotypes can be distinguished: cranial GCA (C-GCA) and large vessel GCA (LV-GCA). C-GCA is usually suspected when cranial manifestations (temporal headaches, jaw claudication, scalp tenderness, or visual disturbances) occur. Isolated LV-GCA is more difficult to diagnose, due to the lack of specificity of clinical features which can be limited to constitutional symptoms and/or unexplained fever. Furthermore, many studies have demonstrated the existence-in varying proportions-of subclinical GCA in patients with apparently isolated PMR features. In PMR patients, the occurrence of clinical features of C-GCA (new onset temporal headaches, jaw claudication, or abnormality of temporal arteries) are highly predictive of C-GCA. Additionally, glucocorticoids' resistance occurring during follow-up of PMR patients, the occurrence of constitutional symptoms, or acute phase reactants elevation are suggestive of associated GCA. Research into the predictive biomarkers of GCA in PMR patients is critical for selecting PMR patients for whom imaging and/or temporal artery biopsy is necessary. To date, Angiopoietin-2 and MMP-3 are powerful for predicting GCA in PMR patients, but these results need to be confirmed in further cohorts. In this review, we discuss the diagnostic challenges of subclinical GCA in PMR patients and will review the predictive factors of GCA in PMR patients.

An update on polymyalgia rheumatica

Polymyalgia rheumatica (PMR) is the most common inflammatory rheumatic disease affecting people older than 50 years and is 2-3 times more common in women. The most common symptoms are pain and morning stiffness in the shoulder and pelvic girdle and the onset may be acute or develop over a few days to weeks. General symptoms such as fatigue, fever and weight loss may occur, likely driven by systemic IL-6 signalling. The pathology includes synovial and periarticular inflammation and muscular vasculopathy. A new observation is that PMR may appear as a side effect of cancer treatment with checkpoint inhibitors. The diagnosis of PMR relies mainly on symptoms and signs combined with laboratory markers of inflammation. Imaging modalities including ultrasound, magnetic resonance imaging and positron emission tomography with computed tomography are promising new tools in the investigation of suspected PMR. However, they are still limited by availability, high cost and unclear performance in the diagnostic workup. Glucocorticoid (GC) therapy is effective in PMR, with most patients responding promptly to 15-25 mg prednisolone per day. There are challenges in the management of patients with PMR as relapses do occur and patients with PMR may need to stay on GC for extended periods. This is associated with high rates of GC-related comorbidities, such as diabetes and osteoporosis, and there are limited data on the use of disease-modifying antirheumatic drugs and biologics as GC sparing agents. Finally, PMR is associated with giant cell arteritis that may complicate the disease course and require more intense and prolonged treatment.

Concurrent baseline diagnosis of giant cell arteritis and polymyalgia rheumatica - A systematic review and meta-analysis

INTRODUCTION

Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) can be concurrent diseases. We aimed to estimate the point-prevalence of concurrent GCA and PMR. Additionally, an incidence rate (IR) of GCA presenting after PMR diagnosis in patients was estimated.

METHODS

Two authors performed a systematic literature search, data extraction and risk of bias assessment independently. Studies assessing cohorts of patients presenting with both GCA and PMR were included. The outcomes were point-prevalence of concurrent GCA and PMR and IR for development of GCA after PMR diagnosis. A meta-analysis was performed to calculate a pooled prevalence of concurrent PMR and GCA.

RESULTS

We identified 29 studies investigating concurrent GCA and PMR. Only two studies applied imaging systematically to diagnose GCA and none to diagnose PMR. GCA presenting after PMR diagnosis was assessed in 12 studies but imaging was not applied systematically. The point-prevalence of concurrent GCA present at PMR diagnosis ranged from 6%-66%. The pooled estimate of the point-prevalence from the meta-analysis was 22%. The point-prevalence of PMR present at GCA diagnosis ranged from 16%-65%. The pooled estimate of the point-prevalence from the meta-analysis was 42%. The IR ranged between 2-78 cases of GCA presenting after PMR per 1000 person-years.

CONCLUSION

This review and meta-analysis support that concurrent GCA and PMR is frequently present at the time of diagnosis. Additionally, we present the current evidence of GCA presenting in patients after PMR diagnosis. These results emphasize the need for studies applying imaging modalities to diagnose GCA.

Polymyalgia Rheumatica: a Common Disease in Seniors

PURPOSE OF THE REVIEW

Polymyalgia rheumatica (PMR) is one of the most common inflammatory rheumatologic condition occurring in older adults. It is characterized by proximal pain and stiffness in the shoulders, neck, and/or pelvic girdle in individuals over 50 years of age along with evidence of an intense systemic inflammatory response. Although the above clinical symptoms are very characteristic for the condition, it can be mimicked by other autoimmune, infectious, malignant, and endocrine disorders chief among which are giant cell arteritis (GCA) and elderly-onset rheumatoid arthritis (EORA). Recently, PMR was reported in relation to treatment with immune checkpoint inhibitors. Current treatment of PMR consists of low-to-medium doses of glucocorticosteroids (GC) with variable response rates and disease recurrence estimated to occur in 50% of patients while tapering down GC doses. In addition, GC-based regimens cause much of the morbidity associated with PMR in older adults, requiring close monitoring for GC-induced toxicity during therapy and highlighting the need for novel therapeutic strategies. Here, we review the latest findings in the field regarding specific etiologic factors, genetic associations, diagnostic methods, and advancements in treatment strategies and disease monitoring indices.

RECENT FINDINGS

Recent discoveries involving novel therapeutic targets in GCA have accelerated the study of PMR pathophysiology and have advanced treatment strategies in PMR management leading to current trials in IL-6 blocking agents. PMR remains an enigmatic inflammatory condition affecting older adults, with current treatment approach causing much morbidity in this patient population. Advancements in our understanding of novel immunopathologic targets can serve as a solid foundation for future treatment strategies in the field.

Handheld Photoacoustic Imager for Theranostics in 3D

A handheld approach to 3D photoacoustic imaging is essential in clinical applications. To this end, we develop a 3D handheld photoacoustic imager for dynamic (temporally and spatially) volumetric visualization. In this 3D imager, the optically transmitting part and the acoustically receiving part are integrated into a single handheld probe with a compact size about 160 mm ×64 mm ×40 mm. Besides, a dedicated imaging reconstruction algorithm for the heterogeneous medium is developed based on the phase-shift migration method in the frequency domain, which deals well with the stratified condition in the designed system. Dynamic 3D imaging supporting flexible handheld operation is demonstrated with needle biopsy and in vitro temperature measurement for photothermal therapy. The development of such a 3D handheld photoacoustic system paves the way for compact and handheld-operating implementations, and its further clinical exploration is promising.

Reviewing the Pathophysiology Behind the Advances in the Management of Giant Cell Arteritis

Improving understanding of the underlying pathophysiology of giant cell arteritis (GCA) is transforming clinical management by identifying novel avenues for targeted therapies. One key area of concern for both clinicians and patients with GCA is glucocorticoid (GC) morbidity. The first randomised controlled trials of targeted treatment to reduce cumulative GC use in GCA have been published, with tocilizumab, an interleukin (IL)-6 receptor inhibitor, now the first ever licensed treatment for GCA. Further potential therapies are emerging owing to our enhanced understanding of the pathophysiology of the disease. Other improvements in the care of our patients are rapid access pathways and imaging techniques, such as ultrasound, which are becoming part of modern rheumatology practice in the UK, Europe and beyond. These have been highlighted in the literature to reduce delay in diagnosis and improve long-term outcomes for those investigated for GCA.

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.

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.

The Role of Ultrasound Compared to Biopsy of Temporal Arteries in the Diagnosis and Treatment of Giant Cell Arteritis (TABUL): a diagnostic accuracy and cost-effectiveness study

BACKGROUND

Giant cell arteritis (GCA) is a relatively common form of primary systemic vasculitis, which, if left untreated, can lead to permanent sight loss. We compared ultrasound as an alternative diagnostic test with temporal artery biopsy, which may be negative in 9-61% of true cases.

OBJECTIVE

To compare the clinical effectiveness and cost-effectiveness of ultrasound with biopsy in diagnosing patients with suspected GCA.

DESIGN

Prospective multicentre cohort study.

SETTING

Secondary care.

PARTICIPANTS

A total of 381 patients referred with newly suspected GCA.

MAIN OUTCOME MEASURES

Sensitivity, specificity and cost-effectiveness of ultrasound compared with biopsy or ultrasound combined with biopsy for diagnosing GCA and interobserver reliability in interpreting scan or biopsy findings.

RESULTS

We developed and implemented an ultrasound training programme for diagnosing suspected GCA. We recruited 430 patients with suspected GCA. We analysed 381 patients who underwent both ultrasound and biopsy within 10 days of starting treatment for suspected GCA and who attended a follow-up assessment (median age 71.1 years; 72% female). The sensitivity of biopsy was 39% [95% confidence interval (CI) 33% to 46%], which was significantly lower than previously reported and inferior to ultrasound (54%, 95% CI 48% to 60%); the specificity of biopsy (100%, 95% CI 97% to 100%) was superior to ultrasound (81%, 95% CI 73% to 88%). If we scanned all suspected patients and performed biopsies only on negative cases, sensitivity increased to 65% and specificity was maintained at 81%, reducing the need for biopsies by 43%. Strategies combining clinical judgement (clinician's assessment at 2 weeks) with the tests showed sensitivity and specificity of 91% and 81%, respectively, for biopsy and 93% and 77%, respectively, for ultrasound; cost-effectiveness (incremental net monetary benefit) was £485 per patient in favour of ultrasound with both cost savings and a small health gain. Inter-rater analysis revealed moderate agreement among sonographers (intraclass correlation coefficient 0.61, 95% CI 0.48 to 0.75), similar to pathologists (0.62, 95% CI 0.49 to 0.76).

LIMITATIONS

There is no independent gold standard diagnosis for GCA. The reference diagnosis used to determine accuracy was based on classification criteria for GCA that include clinical features at presentation and biopsy results.

CONCLUSION

We have demonstrated the feasibility of providing training in ultrasound for the diagnosis of GCA. Our results indicate better sensitivity but poorer specificity of ultrasound compared with biopsy and suggest some scope for reducing the role of biopsy. The moderate interobserver agreement for both ultrasound and biopsy indicates scope for improving assessment and reporting of test results and challenges the assumption that a positive biopsy always represents GCA.

FUTURE WORK

Further research should address the issue of an independent reference diagnosis, standards for interpreting and reporting test results and the evaluation of ultrasound training, and should also explore the acceptability of these new diagnostic strategies in GCA.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Giant Cell Arteritis and Polymyalgia Rheumatica: 2016 Update

Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are both more common among people of North European decent than among Mediterranean people. Women are 2-3 times more commonly affected. Giant cell arteritis and PMR are extremely rare before age 50 years. Polymyalgia rheumatica may be "isolated" or associated with GCA. There is increased expression of inflammatory cytokines in temporal arteries of PMR patients, without overt histological evidence of arteritis. One-third of "isolated" PMR patients have vascular uptake in positron emission tomography (PET) scans, suggesting clinically unrecognized, "hidden" GCA. Typical manifestations of GCA are headache, tenderness over temporal arteries, jaw claudication, PMR, acute vision loss, and low-grade fever. Bilateral aching of the shoulders with morning stiffness is typical for PMR. In both conditions sedimentation rate and C-reactive protein are elevated, and anemia and thrombocytosis may occur. Color duplex ultrasonography of the temporal arteries may aid in GCA diagnosis. Temporal artery biopsy showing vasculitis, often with giant cells, confirms GCA diagnosis. In cases with negative biopsy one must rely on the clinical presentation and laboratory abnormalities. The diagnosis of PMR is made primarily on clinical grounds. Other conditions that may mimic GCA or PMR must be excluded. Glucocorticoids are the treatment of choice for both conditions. Prompt treatment is crucial in GCA, to prevent irreversible complications of acute vision loss and stroke. Addition of low-dose aspirin may further prevent these complications. The average duration of treatment is 2-3 years, but some patients require a prolonged course of treatment, and some may develop disease-related or treatment-related complications. No steroid-sparing agent has been proven to be widely effective thus far, but some promising therapeutic agents are currently being studied.

Advances and challenges in the diagnosis and treatment of polymyalgia rheumatica

Polymyalgia rheumatica (PMR) is a common inflammatory condition that often affects people over the age of 50 years. Characteristic symptoms are shoulder and hip girdle pain and prolonged morning stiffness. Markers of inflammation are often elevated. Clinicians are often faced with the challenge of distinguishing PMR from other conditions, particularly rheumatoid arthritis and spondyloarthropathy that can mimic symptoms of PMR in older people. Additionally, there is an association between PMR and giant cell arteritis, a common large-vessel vasculitis which also affects people over the age of 50 years. Imaging of the large vessels in asymptomatic patients with PMR often reveals findings of subclinical vasculitis. Presently, there are no tests that are specific for the diagnosis of PMR and clinicians rely on a combination of history, physical examination, laboratory tests and imaging studies to make a diagnosis. A recent undertaking by the European League Against Rheumatism/American College of Rheumatology has led to the publication of provisional classification criteria of PMR. Ultrasonography, which is being increasingly used by rheumatologists, can greatly aid in the diagnosis of PMR and often shows changes of synovitis and tenosynovitis. Treatment consists of low doses of glucocorticoids which are associated with morbidity. Evaluation of newer biologic therapies targeting inflammatory cytokines is underway. Despite treatment, relapses are common.

Role of ultrasound in the understanding and management of vasculitis

Vasculitis is characterized by a circumferential vessel-wall thickening ('halo'), which can be visualized by modern imaging techniques. In particular, the resolution of ultrasound has increased to 0.1 mm. Ultrasound detects abnormalities that are pathognomonic even in arteries with a diameter below 1 mm. It is particularly helpful in the diagnosis of large-vessel vasculitides, such as classic temporal arteritis, large-vessel giant-cell arteritis (GCA), Takayasu arteritis and idiopathic aortitis. Echocardiography is important for determining cardiac involvement in Takayasu arteritis and also for examining the coronary arteries of children with suspected Kawasaki disease, which is a medium-vessel vasculitis. In small vessel vasculitides ultrasound has only a role for determining the distribution or organ involvement. Fast-track clinics for the diagnosis of GCA help to initiate treatment before complications such as blindness occur; patients receive appointments within 24 h in these clinics. Clinical examination and ultrasound of temporal and axillary arteries are performed by an experienced rheumatologist. In most cases this is able to determine if GCA is present. Temporal artery biopsy can be still carried out in ambivalent cases. The wall swelling of temporal arteries disappears after 2-3 weeks of glucocorticoid treatment. After 3 days of treatment, diagnosis becomes more difficult with ultrasound in some cases. In larger arteries, such as the axillary arteries, wall thickening disappears within months. It tends to be darker (more hypoechoic) in acute disease because of oedema.

Primary systemic Al amyloidosis presenting as temporal arteritis

Temporal arteritis is most common vasculitis in elderly and imitated by miscellaneous disorders. Temporal artery biopsy is the gold standard test in the diagnosis of giant cell arteritis (GCA). Hereby, we describe a case of a 67-year-old man who presented initially with temporal arteritis; however, a lip biopsy then revealed AL amyloidosis. In this respect, temporal artery biopsy should be performed for definitive diagnosis of GCA particularly patients with systemic symptoms and treatment resistant.

[Polymyalgia rheumatica]

Polymyalgia rheumatica is characterized by bilateral pain in the shoulder and pelvic girdles, malaise, morning stiffness and weight loss. The erythrocyte sedimentation rate (ESR) and the C-reactive protein (CRP) level are elevated. Imaging using ultrasound, magnetic resonance imaging (MRI) or positron emission tomography (PET) displays inflammatory changes in the painful anatomical areas. Nearly all patients are older than 50 years and the average age is 70-75 years. Polymyalgia rheumatica occurs 2-3 times more often in women than in men and some patients exhibit temporal arteritis or giant cell arteritis. Symptoms rapidly decrease with glucocorticoid treatment and the dose can normally be reduced during the course of the disease. Methotrexate may be given only if high glucocorticoid doses do not sufficiently control symptoms. On average treatment can be stopped after 2 years.

Ultrasound applications for the practicing rheumatologist

Musculoskeletal ultrasound is an increasingly used tool for the evaluation and management of rheumatologic diseases. Its utilisation by rheumatologists is varied around the world and is dependent upon training and local expertise. Its applications can be broadly categorised into three main areas; for the education of patients, to aid the rheumatologist in the diagnosis and monitoring of disease, and therapeutically for joint aspiration and injection. Ultrasound is a safe, portable, easily repeatable, dynamic images in multiple planes and cheap form of imaging. Ultrasound however, is operator dependent and has a number of artefacts that can result in misinterpretation. Musculoskeletal Ultrasound uses a number of modes to characterise joint pathology, including grey scale, colour and power Doppler, spectral Doppler, 3D imaging, elastography. Musculoskeletal ultrasound can detect and monitor multiple joint pathologies including synovitis, tenosynovitis, and tendon pathologies, entheseal processes, bone erosions and osteophytes, cartilage changes and bursal pathologies.

Therapeutic approach to giant cell arteritis

Giant cell arteritis (GCA) affects middle-sized or large arteries in individuals over 50 years of age. GCA is characterized by a combination of focal inflammation responsible for arterial stenosis or occlusion and of systemic inflammation manifesting as polymyalgia rheumatica, a decline in general health, and inflammatory anemia. In addition to the typical involvement of the branches of the external carotid arteries, relatively common sites of involvement include the aorta, most notably in its thoracic segment, and the subclavian, axillary, brachial, vertebral, and femoral arteries. The treatment of GCA rests on daily glucocorticoid administration, which should be started on an emergency basis in patients with incipient visual impairments (diplopia or amaurosis fugax). The duration of glucocorticoid therapy is unpredictable and side effects are common. Initial megadose glucocorticoid therapy does not decrease subsequent glucocorticoid requirements. Glucocorticoid therapy regulates the Th17 pathway, which is involved in the prominent vascular and systemic manifestations; but not the Th1 pathway, which may underlie the chronic course of the disease (whereas aspirin, in addition to decreasing platelet aggregation, blocks the Th1 mediator interferon-gamma). Although GCA is classically described as resolving within 1 to 3 years, clinical practice often teaches otherwise. Many patients experience rebound abnormalities in laboratory tests and/or relapses, and some of them have recurrences after an apparently full recovery. Histological documentation is useful to confirm the diagnosis. The effect of methotrexate and TNFα antagonists is modest at best. A few patients have responded to tocilizumab, which suppresses IL-6, a key cytokine in GCA. Life expectancy in GCA patients is similar to that in same-age controls except for a slight excess in vascular mortality shortly after the diagnosis.

Imaging of polymyalgia rheumatica: indications on its pathogenesis, diagnosis and prognosis

OBJECTIVES

Imaging is one of the most appealing techniques to explore PMR, a disease whose causes, development mechanisms and anatomical targets of inflammatory damage are still scarcely known. This review is concerned with an appraisal of PMR with different imaging modalities with a view to highlighting possible clues to its pathogenesis, diagnosis and prognosis.

METHODS

A systematic literature research was performed searching PubMed until July 2010. The Cochrane Library was searched for the relevant reviews, and the abstracts of the ACR and European League Against Rheumatism congresses of the period 2005-10 were reviewed.

RESULTS

A total of 1059 papers were retrieved, 46 of which were selected at the end of the review process; 6 of them were concerned with two different imaging techniques. Of these papers, 6 (11.5%) were concerned with conventional radiology; 8 (15.4%) with scintigraphy; 17 (32.7%) with ultrasonography (US); 15 (28.8%) with MRI; and 6 (11.5%) with PET. MRI, US and PET appeared to be the most promising imaging techniques. Bilateral subacromial bursitis, biceps long head tenosynovitis and trochanteric bursitis were particularly consistent findings. In addition, MRI and PET showed interspinous bursitis and PET frequently showed large-vessel vasculitis. Few papers have addressed the role of imaging for diagnosis, differential diagnosis and prognosis of PMR.

CONCLUSIONS

Imaging plays an important role in the comprehensive evaluation of PMR, including its pathogenesis, diagnosis and prognosis. Most of its potential is still unexplored, which fact should stimulate further research.

Role of ultrasonography in the diagnosis of temporal arteritis

Background

Temporal artery (TA) biopsy is the current standard for diagnosing temporal arteritis, but has limited sensitivity. Colour duplex ultrasonography is a newer, non-invasive method of diagnosing temporal arteritis.

Methods

A systematic review was performed of trials comparing TA biopsy with duplex ultrasonography. Duplex results (halo sign, stenosis or vessel occlusion) were compared with either TA biospy findings or the American College of Rheumatology research criteria for diagnosing temporal arteritis. Trials were identified from MEDLINE, Embase and the Cochrane Library trials register. The performance of duplex ultrasonography was assessed with weighted independent sensitivity and specificity values, and summary receiver operating characteristic curve analysis.

Results

There were 17 eligible studies containing 998 patients. When the halo sign on duplex imaging was compared with TA biopsy, the sensitivity was 75 (95 per cent confidence interval 67 to 82) per cent and the specificity was 83 (78 to 88) per cent. There was no heterogeneity across the eligible studies.

Conclusion

Duplex ultrasonography was relatively accurate for diagnosing temporal arteritis. It should become the first-line investigation, with biopsy reserved for patients with a negative scan.

The diagnostic value of ultrasonography-derived edema of the temporal artery wall in giant cell arteritis: a second meta-analysis

BACKGROUND

Ultrasonography of temporal arteries is not commonly used in the approach of patients with suspected giant cell arteritis (GCA) in clinical practice. A meta-analysis of primary studies available through April 2004 concluded that ultrasonography could indeed be helpful in diagnosing GCA. We specifically re-examined the diagnostic value of the ultrasonography-derived halo sign, a dark hypoechoic circumferential thickening around the artery lumen, indicating vasculitic wall edema, in GCA.

METHODS

Original, prospective studies in patients with suspected GCA that examined ultrasonography findings of temporal arteries using the ACR 1990 classification criteria for GCA as reference standard, published through 2009, were identified. Only eight studies involving 575 patients, 204 of whom received the final diagnosis of GCA, fulfilled technical quality criteria for ultrasound. Weighted sensitivity and specificity estimates of the halo sign were assessed, their possible heterogeneity was investigated and pooled diagnostic odds ratio was determined.

RESULTS

Unilateral halo sign achieved an overall sensitivity of 68% (95% CI, 0.61-0.74) and specificity of 91% (95% CI, 0.88-0.94) for GCA. The values of inconsistency coefficient (I2) of both sensitivity and specificity of the halo sign, showed significant heterogeneity concerning the results between studies. Pooled diagnostic odds ratio, expressing how much greater the odds of having GCA are for patients with halo sign than for those without, was 34 (95% CI, 8.21-138.23). Diagnostic odds ratio was further increased to 65 (95% CI, 17.86-236.82) when bilateral halo signs were present (sensitivity/specificity of 43% and 100%, respectively). In both cases, it was found that DOR was constant across studies.

CONCLUSION

Temporal artery edema demonstrated as halo sign should be always looked for in ultrasonography when GCA is suspected. Providing that currently accepted technical quality criteria are fulfilled, halo sign's sensitivity and specificity are comparable to those of autoantibodies used as diagnostic tests in rheumatology. Validation of revised GCA classification criteria which will include the halo sign may be warranted.

[Myalgia in polymyalgia rheumatica, temporal arteritis and other vasculitides]

Myalgias most commonly occur in polymyalgia rheumatica (PMR). About 45% of patients with giant cell arteritis present with symptoms of PMR. Other vasculitides may also lead to arthralgia and myalgia. While shoulder and pelvic pain is characteristic for PMR pain often also occurs in the back of the neck and in the region of the thoracic spine. In addition, patients often present with malaise, morning stiffness and weight loss. CRP and ESR are elevated. Ultrasound and MRI delineate minor synovitis, tenosynovitis and bursitis in the shoulder. Hip joint synovitis and trochanteric bursitis are also commonly seen. PMR should be distinguished from rheumatoid arthritis. The initial treatment comprises a prednisolone dose of 15-25 mg/day, followed by a weekly decrease of 1-2.5 mg. Once 10 mg/day has been reached the dose should be reduced more slowly.

Imaging for large-vessel vasculitis

PURPOSE OF REVIEW

Ultrasonography, MRI, and PET are increasingly studied in large-vessel vasculitis. They have broadened our knowledge on these disorders and have a place in the diagnostic approach of these patients.

RECENT FINDINGS

Temporal artery ultrasonography can be used to guide the surgeon to that artery segment with the clearest 'halo' sign to perform a biopsy, or in experienced hands can even replace biopsy. The distal subclavian, axillary, and brachial arteries can also be examined. High-resolution MRI depicts superficial cranial and extracranial involvement patterns in giant cell arteritis (GCA). Contrast enhancement is prominent in active inflammation and decreases under successful steroid therapy. Presence of aortic complications such as aneurysm or dissection can be ruled out within the same investigation. Large thoracic vessel FDG-uptake is seen in the majority of patients with GCA, especially at the subclavian arteries and the aorta. FDG-PET cannot predict which patients are bound to relapse, and once steroids are started, interpretation is hazardous, which makes its role in follow-up uncertain. Increased thoracic aortic FDG-uptake at diagnosis of GCA may be a bad prognostic factor for later aortic dilatation. In patients with isolated polymyalgia rheumatica - who have less intense vascular FDG uptake - symptoms are caused by inflammation around the shoulders, hips, and spine.

SUMMARY

Ultrasonography, MRI, and PET remain promising techniques in the scientific and clinical approach of large-vessel vasculitis.

Limits and perspectives of ultrasound in the diagnosis and management of rheumatic diseases

Musculoskeletal sonography (MSUS) has played a growing role in the diagnosis and management of rheumatic diseases, enabling the imaging of synovitis, bone erosion, and cartilage damage in the early phase of arthritis. "Dynamic" evaluation of tendons and help in guiding needle positioning in interventional manoeuvres are some of the other reasons for its success. MSUS, particularly when coupled with power Doppler (PD) examination, has recently been shown to be an efficient tool for monitoring disease activity and progression in rheumatoid arthritis, spondyloarthritis, crystal-related arthropathy, and osteoarthritis, with general consensus on its interesting results. More specifically, the PD signal has proved to be a simple and promising tool for short-term monitoring of synovial vascularity changes induced by steroids or biological agents in RA patients. MSUS has some limits, because of the physical properties of US and the quality of the equipment; it is, moreover, an operator-related imaging technique, with few standardized protocols. Future goals should be standardization of the examining approach in grey scale and Doppler ultrasound (US), including use of new equipment (3D US), extensive use in other fields (i.e. connective tissue diseases and vasculitis), and possible new applications (e.g. thoracic US).

[Value of the Doppler-ultrasonography for the diagnosis of temporal arteritis]

BACKGROUND AND OBJECTIVE

The aim of this study was to investigate the accuracy of color Doppler-ultrasonography (CDU) compared with biopsy for the diagnosis of temporal arteritis (TA).

PATIENTS AND METHOD

Twenty-three patients with suspected TA on the basis of clinical criteria were evaluated with CDU prior to temporal artery biopsy. The presence of a hypoechoic halo, suggesting edema of the inflamed vessel, and inflammatory stenoses were registered. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and eficiency or global test value (GTV) were evaluated.

RESULTS

All patients completed a bilateral CDU examination of temporal arteries, and in 72% of patients the biopsy was negative for TA. When the presence of an halo in CDU examination was regarded as determinant for disease, sensitivity, specificity, PPV, NPV and GTV compared with TA histologic confirmation were 80%, 92%, 80%, 92% and 88%, respectively. When the criteria used was presence of the halo sign with or without inflammatory stenosis, the values were 100%, 77%, 62.5%, 100% and 83% respectively.

CONCLUSIONS

Because of the high sensitivity and NPV, we consider CDU as a good screening test for the diagnosis of TA.

[Imaging procedures in rheumatology: imaging in vasculitis]

In small vessel vasculitides, imaging studies aid in determining disease extent and activity, localization for biopsy, and for disease monitoring. They do not directly delineate the vasculitic lesion. Imaging studies focus on the upper and lower respiratory tract. Cranial magnetic resonance imaging (MRI) shows upper respiratory and retrobulbar granuloma in Wegener's granulomatosis. Furthermore, MRI depicts both mastoiditis and mucosal inflammation of the ear, nose, and throat. It is sensitive but not specific for the detection of cerebral vasculitis. Computed tomography (CT) reliably detects osseous facial lesions. Chest radiography in two planes remains the standard method of investigation for the lower respiratory tract. High-resolution CT aids in detecting further interstitial pathologies. Medium-sized vasculitides frequently occur with aneurysms. The classification criteria for polyarteritis nodosa involve the angiographic detection of visceral aneurysms. Patients with Kawasaki disease may develop coronary aneurysms that may be described by echocardiography or angiography according to diagnostic criteria. In large-vessel vasculitides such as temporal arteritis (giant cell arteritis) and Takayasu arteritis, MRI, MR-angiography, CT, CT-angiography, and duplex sonography delineate characteristic homogenous wall thickening with or without stenoses in the aorta and other arteries. There is a high correlation with angiography and positron emission tomography. Duplex sonography of the temporal arteries has a high sensitivity and specificity for the diagnosis. Data on temporal artery MRI in giant cell arteritis have recently been published.

Colour duplex sonography of temporal arteries before decision for biopsy: a prospective study in 55 patients with suspected giant cell arteritis

Although a temporal artery biopsy is the gold standard for the diagnosis of giant cell arteritis (GCA), there is considerable evidence that characteristic signs demonstrated by colour duplex sonography (CDS) of the temporal arteries may be of diagnostic importance. We aimed to test the hypothesis that CDS can replace biopsy in the algorithm for the approach to diagnose GCA. Bilateral CDS was performed in consecutive patients older than 50 years with clinically suspected GCA, as well as in 15 age- and gender-matched control subjects with diabetes mellitus and/or stroke and 15 healthy subjects, to assess flow parameters and the possible presence of a dark halo around the arterial lumen. Unilateral temporal artery biopsy was then performed in patients with suspected GCA, which was directed to a particular arterial segment in case a halo was detected in CDS. Final diagnoses, after completion of a 3-month follow-up in 55 patients, included GCA (n = 22), polymyalgia rheumatica (n = 12), polyarteritis nodosa, Wegener's, and Adamantiades-Behçet's diseases (n = 3), and neoplastic (n = 8) and infectious diseases (n = 10). A dark halo of variable size (0.7-2.0 mm) around the vessel lumen was evident at baseline CDS in 21 patients (in 12 and 9 uni- or bilaterally, respectively) but in none of the controls. The presence of unilateral halo alone yielded 82% sensitivity and 91% specificity for GCA, whereas the specificity reached 100% when halos were found bilaterally. Blood-flow abnormal parameters (temporal artery diameter, peak systolic blood-flow velocities, stenoses, occlusions) were common in GCA and non-GCA patients, as well as in healthy and atherosclerotic disease-control, elderly subjects. At follow-up CDS examinations performed at 2 and 4 weeks after initiation of corticosteroid treatment for GCA, halos disappeared in all 18 patients (9 and 9, respectively). We conclude that CDS, an inexpensive, non-invasive, and easy-to-perform method, allows a directional biopsy that has an increased probability to confirm the clinical diagnosis. Biopsy is not necessary in a substantial proportion of patients in whom bilateral halo signs can be found by CDS.