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

Optic Nerve Sheath Measurement on Ultrasound: A Novel Diagnostic Test for Giant Cell Arteritis

OBJECTIVE

Optic nerve sheath enhancement on magnetic resonance imaging has been reported in patients with giant cell arteritis (GCA), with or without visual manifestations. Whether similar findings can be documented on ultrasound is unknown. Optic nerve ultrasound is a point-of-care, easy to learn, rapid, and noninvasive technique. This study aims to investigate whether optic nerve sheath diameter (ONSD) measured on ultrasound is useful in the diagnosis of active, new-onset GCA.

METHODS

A single-center, diagnostic accuracy study was performed from June to November 2022 on consecutive eligible patients referred for suspected GCA. Optic nerve ultrasound was performed on both eyes. The ONSD (includes the optic nerve and its sheath) and optic nerve diameter (OND) were measured 3 mm behind the ocular globe. The presence or absence of GCA was confirmed clinically 6 months later. Multivariable linear regression, adjusting for age and sex, was used to determine the association between optic nerve ultrasound measures and final GCA diagnosis.

RESULTS

Thirty participants were enrolled, including nine participants with a final diagnosis of GCA. Mean ± SD ONSD was 5.98 ± 1.17 mm in patients with GCA and 4.02 ± 0.99 mm in patients without GCA. Mean ONSD was greater by 1.26 mm in patients with GCA (95% confidence interval 0.30-2.21 mm, P = 0.01) compared with those without GCA, adjusting for age and sex. Mean ± SD OND was 2.97 ± 0.46 mm in patients with GCA and 2.47 ± 0.58 mm in patients without GCA. There was no evidence of an association between GCA diagnosis and OND.

CONCLUSION

Patients with GCA had a significantly greater ONSD on ultrasound than patients without GCA. Optic nerve ultrasound may represent a novel, rapid, bedside diagnostic test for GCA. A large prospective study is required to confirm these findings and evaluate whether ONSD can be used as a disease activity biomarker in GCA.

The DANIsh VASculitis cohort study: protocol for a national multicenter prospective study including incident and prevalent patients with giant cell arteritis and polymyalgia rheumatica

The DANIsh VASculitis cohort study, DANIVAS, is an observational national multicenter study with the overall aim to prospectively collect protocolized clinical data and biobank material from patients with polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) diagnosed and/or followed at Danish rheumatology departments. A long-term key objective is to investigate whether the use of new clinically implemented diagnostic imaging modalities facilitates disease stratification in the GCA-PMR disease spectrum. In particular, we aim to evaluate treatment requirements in GCA patients with and without large-vessel involvement, treatment needs in PMR patients with and without subclinical giant cell arteritis, and the prognostic role of imaging with respect to aneurysm development. Hence, in GCA and PMR, imaging stratification is hypothesized to be able to guide management strategies. With an established infrastructure within rheumatology for clinical studies in Denmark, the infrastructure of the Danish Rheumatologic Biobank, and the possibility to cross-link data with valid nationwide registries, the DANIVAS project holds an exceptional possibility to collect comprehensive real-world data on diagnosis, disease severity, disease duration, treatment effect, complications, and adverse events. In this paper, we present the research protocol for the DANIVAS study. Clinical trial registration: https://clinicaltrials.gov/, identifier NCT05935709.

Polymyalgia rheumatica shows metabolomic alterations that are further altered by glucocorticoid treatment: Identification of metabolic correlates of fatigue

OBJECTIVE

In polymyalgia rheumatica (PMR), glucocorticoids (GCs) relieve pain and stiffness, but fatigue may persist. We aimed to explore the effect of disease, GCs and PMR symptoms in the metabolite signatures of peripheral blood from patients with PMR or the related disease, giant cell arteritis (GCA).

METHODS

Nuclear magnetic resonance spectroscopy was performed on serum from 40 patients with untreated PMR, 84 with new-onset confirmed GCA, and 53 with suspected GCA who later were clinically confirmed non-GCA, and 39 age-matched controls. Further samples from PMR patients were taken one and six months into glucocorticoid therapy to explore relationship of metabolites to persistent fatigue. 100 metabolites were identified using Chenomx and statistical analysis performed in SIMCA-P to examine the relationship between metabolic profiles and, disease, GC treatment or symptoms.

RESULTS

The metabolite signature of patients with PMR and GCA differed from that of age-matched non-inflammatory controls (R2 > 0.7). There was a smaller separation between patients with clinically confirmed GCA and those with suspected GCA who later were clinically confirmed non-GCA (R2 = 0.135). In PMR, metabolite signatures were further altered with glucocorticoid treatment (R2 = 0.42) but did not return to that seen in controls. Metabolites correlated with CRP, pain, stiffness, and fatigue (R2 ≥ 0.39). CRP, pain, and stiffness declined with treatment and were associated with 3-hydroxybutyrate and acetoacetate, but fatigue did not. Metabolites differentiated patients with high and low fatigue both before and after treatment (R2 > 0.9). Low serum glutamine was predictive of high fatigue at both time points (0.79-fold change).

CONCLUSION

PMR and GCA alter the metabolite signature. In PMR, this is further altered by glucocorticoid therapy. Treatment-induced metabolite changes were linked to measures of inflammation (CRP, pain and stiffness), but not to fatigue. Furthermore, metabolite signatures distinguished patients with high or low fatigue.

Diagnostic Strategy Using Color Doppler Ultrasound of Temporal Arteries in Patients With High Clinical Suspicion of Giant Cell Arteritis : A Prospective Cohort Study

BACKGROUND

Giant cell arteritis (GCA) is the most prevalent systemic vasculitis in people older than 50 years. Any delay in diagnosis impairs patients' quality of life and can lead to permanent damage, particularly vision loss.

OBJECTIVE

To evaluate a diagnostic strategy for GCA using color Doppler ultrasound of the temporal artery as a first-line diagnostic test, temporal artery biopsy (TAB) as a secondary test, and physician expertise as the reference method.

DESIGN

Prospective multicenter study with a 2-year follow-up. (ClinicalTrials.gov: NCT02703922).

SETTING

Patients were referred by their general practitioner or ophthalmologist to a physician with extensive experience in GCA diagnosis and management in one of the participating centers: 4 general and 2 university hospitals.

PATIENTS

165 patients with high clinical suspicion of GCA, aged 79 years (IQR, 73 to 85 years).

INTERVENTION

The diagnostic procedure was ultrasound, performed less than 7 days after initiation of corticosteroid therapy. Only ultrasound-negative patients underwent TAB.

MEASUREMENTS

Bilateral temporal halo signs seen on ultrasound were considered positive. Ultrasound and TAB results were compared with physician-diagnosed GCA based on clinical findings and other imaging.

RESULTS

Diagnosis of GCA was confirmed in 44%, 17%, and 21% of patients by ultrasound, TAB, and clinical expertise and/or other imaging tests, respectively. Their diagnosis remained unchanged at 1 month, and 2 years for those with available follow-up data. An alternative diagnosis was made in 18% of patients. The proportion of ultrasound-positive patients among patients with a clinical GCA diagnosis was 54% (95% CI, 45% to 62%).

LIMITATION

Small sample size, no blinding of ultrasound and TAB results, lack of an objective gold-standard comparator, and single diagnostic strategy.

CONCLUSION

By using ultrasound of the temporal arteries as a first-line diagnostic tool in patients with high clinical suspicion of GCA, further diagnostic tests for patients with positive ultrasound were avoided.

PRIMARY FUNDING SOURCE

Tender "Recherche CH-CHU Poitou-Charentes 2014."

Cranial involvement in giant cell arteritis

Since its first clinical description in 1890, extensive research has advanced our understanding of giant cell arteritis, leading to improvements in both diagnosis and management for affected patients. Imaging studies have shown that the disease frequently extends beyond the typical cranial arteries, also affecting large vessels such as the aorta and its proximal branches. Meanwhile, advances in comprehending the underlying pathophysiology of giant cell arteritis have given rise to numerous potential therapeutic agents, which aim to minimise the need for glucocorticoid treatment and prevent flares. Classification criteria for giant cell arteritis, as well as recommendations for management, imaging, and treat-to-target have been developed or updated in the last 5 years, and current research encompasses a broad spectrum covering basic, translational, and clinical research. In this Series paper, we aim to discuss the current understanding of giant cell arteritis with cranial manifestations, describe the clinical approach to this condition, and explore future directions in research and patient care.

Broadening the clinical spectrum of giant cell arteritis: from the classic cranial to the predominantly extracranial pattern of the disease

INTRODUCTION

Giant cell arteritis (GCA) is a large vessel (LV) vasculitis that affects people aged 50 years and older. Classically, GCA was considered a disease that involved branches of the carotid artery. However, the advent of new imaging techniques has allowed us to reconsider the clinical spectrum of this vasculitis.

AREASCOVERED

This review describes clinical differences between patients with the cranial GCA and those with a predominantly extracranial LV-GCA disease pattern. It highlights differences in the frequency of positive temporal artery biopsy depending on the predominant disease pattern and emphasizes the relevance of imaging techniques to identify patients with LV-GCA without cranial ischemic manifestations. The review shows that so far there are no well-established differences in genetic predisposition to GCA regardless of the predominant phenotype.

EXPERT COMMENTARY

The large branches of the extracranial arteries are frequently affected in GCA. Imaging techniques are useful to identify the presence of 'silent' GCA in people presenting with polymyalgia rheumatica or with nonspecific manifestations. Whether these two different clinical presentations of GCA constitute a continuum in the clinical spectrum of the disease or whether they may be related but are definitely different conditions needs to be further investigated.

Giant Cell Arteritis

Giant cell arteritis (GCA) is the most common primary vasculitis and is associated with potential bilateral blindness. Neither clinical nor laboratory evidence is simple and unequivocal for this disease, which usually requires rapid and reliable diagnosis and therapy. The ophthalmologist should consider GCA with the following ocular symptoms: visual loss or visual field defects, transient visual disturbances (amaurosis fugax), diplopia, eye pain, or new onset head or jaw claudication. An immediate ophthalmological examination with slit lamp, ophthalmoscopy, and visual field, as well as color duplex ultrasound of the temporal artery should be performed. If there is sufficient clinical suspicion of GCA, corticosteroid therapy should be initiated immediately, with prompt referral to a rheumatologist/internist and, if necessary, temporal artery biopsy should be arranged. Numerous developments in modern imaging with colour duplex ultrasonography, MRI, and PET-CT have the potential to compete with the classical, well-established biopsy of a temporal artery. Early determination of ESR and CRP may support RZA diagnosis. Therapeutically, steroid-sparing immunosuppression with IL-6 blockade or methotrexate can be considered. These developments have led to a revision of both the classification criteria and the diagnostic and therapeutic recommendations of the American College of Rheumatologists and the European League against Rheumatism, which are summarised here for ophthalmology.

Development of a diagnostic prediction model for giant cell arteritis by sequential application of Southend Giant Cell Arteritis Probability Score and ultrasonography: a prospective multicentre study

BACKGROUND

Giant cell arteritis is a critically ischaemic disease with protean manifestations that require urgent diagnosis and treatment. European Alliance of Associations for Rheumatology (EULAR) recommendations advocate ultrasonography as the first investigation for suspected giant cell arteritis. We developed a prediction tool that sequentially combines clinical assessment, as determined by the Southend Giant Cell Arteritis Probability Score (SGCAPS), with results of quantitative ultrasonography.

METHODS

This prospective, multicentre, inception cohort study included consecutive patients with suspected new onset giant cell arteritis referred to fast-track clinics (seven centres in Italy, the Netherlands, Spain, and UK). Final clinical diagnosis was established at 6 months. SGCAPS and quantitative ultrasonography of temporal and axillary arteries with three scores (ie, halo count, halo score, and OMERACT GCA Score [OGUS]) were performed at diagnosis. We developed prediction models for diagnosis of giant cell arteritis by multivariable logistic regression analysis with SGCAPS and each of the three ultrasonographic scores as predicting variables. We obtained intraclass correlation coefficient for inter-rater and intra-rater reliability in a separate patient-based reliability exercise with five patients and five observers.

FINDINGS

Between Oct 1, 2019, and June 30, 2022, we recruited and followed up 229 patients (150 [66%] women and 79 [34%] men; mean age 71 years [SD 10]), of whom 84 were diagnosed with giant cell arteritis and 145 with giant cell arteritis mimics (controls) at 6 months. SGCAPS and all three ultrasonographic scores discriminated well between patients with and without giant cell arteritis. A reliability exercise showed that the inter-rater and intra-rater reliability was high for all three ultrasonographic scores. The prediction model combining SGCAPS with the halo count, which was termed HAS-GCA score, was the most accurate model, with an optimism-adjusted C statistic of 0·969 (95% CI 0·952 to 0·990). The HAS-GCA score could classify 169 (74%) of 229 patients into either the low or high probability groups, with misclassification observed in two (2%) of 105 patients in the low probability group and two (3%) of 64 of patients in the high probability group. A nomogram for easy application of the score in daily practice was created.

INTERPRETATION

A prediction tool for giant cell arteritis (the HAS-GCA score), combining SGCAPS and the halo count, reliably confirms and excludes giant cell arteritis from giant cell arteritis mimics in fast-track clinics. These findings require confirmation in an independent, multicentre study.

FUNDING

Royal College of Physicians of Ireland, FOREUM.

Cost-effectiveness analysis of the diagnosis of temporal arteritis

Temporal arteritis (TA) is the most common form of systemic vasculitis. Its diagnosis is based on criteria proposed by the American College of Rheumatology (1990), and its treatment is high-dose corticosteroids. Our objective is to assess the cost of diagnosing TA, and secondarily, cost-effective analysis of different diagnostic strategies (clinical, biopsy, doppler ultrasound) and therapeutic strategies (corticosteroid suspension).

MATERIAL AND METHOD

Observational, retrospective study has been carried out on patients with AT (2012-2021). Demographic data, comorbidities, signs and symptoms suggestive of AT were collected. AT was diagnosed with a score ≥ 3 according to American College of Rheumatoloy criteria (ACR-SCORE). The costs of diagnosis and treatment modification were analysed.

RESULTS

Seventy-five patients have been included, median age 77 (46-87) years. Headache, temporal pain and jaw claudication were significant for the diagnosis of TA. Patients with a halo on Doppler ultrasound and a positive biopsy have significantly elevated ESR and CRP compared to patients who do not. The cost of the AT diagnosis was 414.7 euros/patient. If we use ACR-SCORE ≥ 3-echodoppler it is 167.2 є/patient (savings 59.6%) and ACR-SCORE ≥ 3-biopsy 339.75 є/patient (savings 18%). If the corticosteroid was removed and a biopsy was performed, 21.6 є/patient (94.7% savings), if the corticosteroid was removed and Doppler ultrasound was performed, 10.6 є/patient (97.4% savings).

CONCLUSIONS

Headache, temporary pain and jaw claudication are predictors of AT. Elevated ESR and CRP are predictors of positive biopsy and presence of halo on ultrasound. The uses of ACR-SCORE ≥ 3 with Doppler ultrasound or biopsy, and with corticosteroid suspension, are cost-effective.

Tomographic ultrasound for three-dimensional visualization of temporal arteries

OBJECTIVE

Conventional two-dimensional ultrasound has been assessed for the non-invasive diagnosis of giant cell arteritis (GCA), but the results are operator dependent, resulting in low sensitivity. Tomographic three-dimensional (3D) ultrasound is a novel technique that enables the objective documentation of vessel geometry. Here, for the first time, its utility is assessed for visualizing temporal arteries.

METHOD

The temporal artery of 14 healthy subjects and three subjects with suspected GCA was examined using tomographic 3D ultrasound.

RESULTS

This technique enabled 3D mapping of the architecture of the temporal artery. The inner and outer vessel diameters showed considerable interindividual variability. However, calculation of the vessel wall fraction revealed the combination of vessel wall thickening and lumen narrowing, which may be indicative of GCA.

CONCLUSIONS

This proof-of-concept study indicates that tomographic 3D ultrasound can be used for objective mapping of the temporal artery. The technique must be evaluated regarding its diagnostic sensitivity in GCA before it can be introduced in clinical practice.

The role of color doppler ultrasonography in the diagnosis of giant cell arteritis in ophthalmic patients

PURPOSE

In the case of ischemic optic neuropathy (ION) or retinal artery occlusion (RAO), distinguishing arteritic from non-arteritic can limit or prevent irreversible bilateral blindness. Here, the utility of color Doppler ultrasonography (CDUS) in diagnosing giant cell arteritis (GCA) was evaluated.

METHODS

In this retrospective analysis, a total of 38 cases diagnosed with ION or RAO were included, that presented to our department in the years 2018 up to 2021 and underwent both CDUS and temporal artery biopsy (TAB). The evaluation is based on TAB as reference standard.

RESULTS

CDUS resulted in a sensitivity of 65.0% and a specificity of 100% (when excluding two inconclusive assessments). Therefore, when limiting TAB to only suspected cases with negative or unclear CDUS findings, the sensitivity and the specificity would remain unchanged at 100%, while reducing the need for TAB by 42.1%.

CONCLUSION

Overall, the data suggest the implementation of a stepwise diagnostic algorithm to confirm or rule out GCA, in which the CDUS plays a key role, thus omitting the requirement for TAB in many cases.

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.

Predictive Factors for Biopsy-Negative Giant Cell Arteritis and Alternative Diagnoses in a Neuro-Ophthalmology Context

Giant cell arteritis is a challenging diagnosis for patients given the high prevalence of negative temporal artery biopsies (TAB). Despite the lack of histopathological evidence of giant cell arteritis in the TAB, patients can still have TAB-negative giant cell arteritis. The purpose of this paper is to analyse the predictors for TAB-negative giant cell arteritis and the alternative diagnosis of biopsy-negative patients without a giant cell arteritis diagnosis. A retrospective electronic database review of all TABs performed at the Royal Victorian Eye and Ear Hospital from February 2015 to May 2020. Logistic regression analysis was performed to determine predictive factors for a diagnosis of TAB-negative giant cell arteritis. In all cases, a clinical diagnosis of TAB-negative giant cell arteritis was determined by a neuro-ophthalmologist. Alternative diagnoses for negative TABs were identified and explored. A total of 368 TABs were analysed with 287 (78%) negative for histopathological evidence of GCA. Twenty-seven (9.4%) patients were diagnosed and treated as TAB-negative giant cell arteritis. The clinical predictors of a TAB-negative giant cell arteritis diagnosis were the presence of jaw claudication (OR 2.77, 95% CI 1.10-6.98) and CRP (OR 1.02, 95% CI 1.00-1.03). Alternative diagnoses included non-specific headache, non-arteritic anterior ischaemic optic neuropathy, retinal vessel occlusions, and ocular nerve palsies. Predictive factors for a diagnosis of TAB-negative giant cell arteritis were jaw claudication and an elevated CRP. Several alternative diagnoses can be considered for patients with a negative TAB in a neuro-ophthalmology context.

Determination of the Value of Color Doppler Ultrasound in Patients With a Clinical Suspicion of Giant Cell Arteritis

OBJECTIVE

It is urgent to diagnose giant cell arteritis (GCA) as quickly as possible to prevent irreversible blindness. The traditional gold standard for diagnosing GCA is temporal artery biopsy (TAB). However, TAB lacks diagnostic performance and carries out risks of surgical intervention. The noninvasive color Doppler ultrasound (CDU) seems to be a promising alternative. This study is designed to assess the diagnostic value of CDU in daily clinical practice.

METHODS

In this prospective cohort study, patients with a clinical suspicion of active GCA were included and underwent a CDU of the temporal arteries. If deemed necessary by the referrer, a TAB and/or 18F-fluorodeoxyglucose positron emission tomography with computed tomography was performed. The retrospective clinical diagnosis was determined 1 year after inclusion by two physicians experienced in the field of vasculitis.

RESULTS

242 patients were included and GCA was diagnosed in 73 (30%) patients by the defined retrospective clinical diagnosis. Compared with the retrospective diagnosis, CDU has a sensitivity of 60% (48-72), specificity of 94% (89-97), positive predictive value (PPV) of 81% (70-89), negative predictive value (NPV) of 85% (80-88), and an accuracy of 84% (78-88). A total of 84 (35%) patients underwent TAB. TAB has a sensitivity of 66% (51-79), specificity of 100% (90-100), PPV of 100% (100), NPV of 67% (58-75), and an accuracy of 80% (70-88).

CONCLUSION

This study shows comparable diagnostic performance for CDU and TAB and even better CDU results with a bilateral halo present. Considering the advantages of the noninvasive CDU, it is the diagnostic tool of choice.

Utility of applying a diagnostic algorithm in giant cell arteritis based on the level of clinical suspicion

INTRODUCTION

To reach the diagnosis of giant cell arteritis (GCA), signs, symptoms, laboratory tests, imaging findings, and occasionally anatomopathological results from temporal artery biopsy are evaluated. This study describes the results of an algorithm analysis based on clinical and ultrasound evaluation of patients with suspected GCA, highlighting its diagnostic utility by contrasting its use in different clinical suspicion scenarios.

METHOD

Prospective multicenter study evaluating patients referred with suspected GCA through a preferential circuit (fast track), grouping them according to low or high clinical suspicion of GCA. Each of these scenarios is evaluated by biopsy and ultrasound for all patients, resulting in positive, indeterminate, or negative outcomes, yielding six possible groups. Potential areas of improvement are explored, emphasizing that, following a negative or indeterminate ultrasound, 18-FDG-PET-CT could be recommended. We analyze the results and application of a diagnostic algorithm, confirming its efficiency and applicability based on whether there is high or low clinical suspicion.

RESULTS

Sixty-nine patients (41 in the high suspicion group and 28 in the low suspicion group). There were 41 new diagnoses of GCA: 35 in the high suspicion group and 6 in the low suspicion group. Using ultrasound alone, the initial algorithm has an overall diagnostic efficiency of 72.5%, which improves to 80.5% when including 18F-FDG-PET/CT. The negative predictive value of ultrasound in patients with low clinical suspicion is 84.6%, and the positive predictive value of ultrasound in patients with high suspicion is 100%, improving sensitivity from 57.1% to 80.8% with 18F-FDG-PET/CT in this scenario. Temporal artery biopsy was performed on all patients, with no differences in sensitivity or specificity compared to ultrasound. In cases where all three tests - ultrasound, biopsy, and 18F-FDG-PET/CT - are performed, sensitivity increases to 92.3% in patients with high clinical suspicion.

CONCLUSION

In situations of high clinical suspicion, the algorithm provides sufficient information for the diagnosis of GCA if ultrasound is positive. A negative ultrasound is sufficient to rule out the diagnosis in the context of low clinical suspicion. 18-FDG-PET-CT may be useful in patients with high suspicion and negative or indeterminate ultrasound results.

Multimodality Imaging in Cranial Giant Cell Arteritis: First Experience with High-Resolution T1-Weighted 3D Black Blood without Contrast Enhancement Magnetic Resonance Imaging

In order to support or refute the clinical suspicion of cranial giant cell arteritis (GCA), a supplemental imaging modality is often required. High-resolution black blood Magnetic Resonance Imaging (BB MRI) techniques with contrast enhancement can visualize artery wall inflammation in GCA. We compared findings on BB MRI without contrast enhancement with findings on 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/low-dose computed tomography (2-[18F]FDG PET/CT) in ten patients suspected of having GCA and in five control subjects who had a 2-[18F]FDG PET/CT performed as a routine control for malignant melanoma. BB MRI was consistent with 2-[18F]FDG PET/CT in 10 out of 10 cases in the group with suspected GCA. In four out of five cases in the control group, the BB MRI was consistent with 2-[18F]FDG PET/CT. In this small population, BB MRI without contrast enhancement shows promising performance in the diagnosis of GCA, and might be an applicable imaging modality in patients.

Transitions in vascular ultrasonography findings of temporal arteritis in a GCA case with progressive temporal headache and visual impairment

The European League Against Rheumatism and the American College of Rheumatology have stated that the halo sign on vascular ultrasonography (v-US) is relevant in diagnosing giant cell arteritis (GCA) and is equivalent to temporal artery biopsy. However, there are only a few reports about transitions in v-US findings after glucocorticoid (GC) therapy. We report the transitions in the v-US findings in a case of GCA after GC therapy. The patient had rapidly progressive symptoms, and there were concerns about blindness. After GC therapy, we first observed improvement in headache and visual impairment symptoms within 1 week, followed by rapid improvement in laboratory findings within 2 weeks. Subsequently, there were improvements in v-US findings after more than 2 months. In conclusion, these findings showed a dissociation between improvements in clinical symptoms and v-US findings of the temporal artery. Additionally, this case suggests that regular examination of v-US findings is useful in evaluating GCA with evident vascular wall thickness before GC therapy.

Comparing Diagnostic Performance of Short and Long [18F]FDG-PET Acquisition Times in Giant Cell Arteritis

(1) Background: In giant cell arteritis (GCA), the assessment of cranial arteries using [18F]fluorodeoxyglucose ([18F]FDG) positron emission tomography (PET) combined with low-dose computed tomography (CT) may be challenging due to low image quality. This study aimed to investigate the effect of prolonged acquisition time on the diagnostic performance of [18F]FDG PET/CT in GCA. (2) Methods: Patients with suspected GCA underwent [18F]FDG-PET imaging with a short acquisition time (SAT) and long acquisition time (LAT). Two nuclear medicine physicians (NMPs) reported the presence or absence of GCA according to the overall image impression (gestalt) and total vascular score (TVS) of the cranial arteries. Inter-observer agreement and intra-observer agreement were assessed. (3) Results: In total, 38 patients were included, of whom 20 were diagnosed with GCA and 18 were without it. Sensitivity and specificity for GCA on SAT scans were 80% and 72%, respectively, for the first NMP, and 55% and 89% for the second NMP. On the LAT scans, these values were 65% and 83%, and 75% and 83%, respectively. When using the TVS, LAT scans showed especially increased specificity (94% for both NMPs). Observer agreement was higher on the LAT scans compared with that on the SAT scan. (4) Conclusions: LAT combined with the use of the TVS may decrease the number of false-positive assessments of [18F]FDG PET/CT. Additionally, LAT and TVS may increase both inter and intra-observer agreement.

Giant cell temporal arteritis: a clinicopathological study with emphasis on unnecessary biopsy

Introduction

Temporal artery (TA) biopsy is commonly used for the diagnosis of giant cell arteritis (GCA). However, a positive biopsy is no longer mandatory for diagnosis. This study aims to correlate the histopathological findings of TA biopsies in suspected cases of GCA to the clinical presentation in an ophthalmic tertiary eye care center to draw useful conclusions and advocate the possible implementation of guidelines for TA biopsy.

Methods

Data was collected from patients' medical records including, demographics, clinical data, and histopathological findings and diagnosis. The 2022 American College of Rheumatology/ European Alliance of Associations for Rheumatology (ACR/EULAR) criteria have been used and partially adopted as a guide to compare the variables between TA biopsy-positive and negative groups as well as the TA biopsy-positive group and the group of patients with TA biopsy showing atherosclerosis.

Results

Out of the total 35 patients who underwent a TA biopsy during the period of 23 years, 22.9% of patients had histopathological findings consistent with GCA and 42.9% had TA atherosclerotic changes, while the remaining 34.3% had histologically unremarkable TA. The mean age of all patients was 66 ± 10.9 years. Slightly more than half were females (54.3%) and the remaining were males (45.7%). In the group with positive TA biopsies, the mean age was 71 ± 8.4 years with a higher female predominance (female-to-male ratio of 5:3). The mean diagnostic clinical score used in our study was higher (7.5 ± 2.33) in the GCA-positive group when compared to the other groups with statistical significance (mean of 4.85 ± 2.01 in patients with overall GCA-negative biopsies and 5.13 ± 2.10 in the group with atherosclerosis). Other three clinical variables that were found to be statistically significant in the GCA biopsy-positive group were scalp tenderness, jaw claudication, and optic nerve pallor.

Discussion

The mean age (71 ± 8.4 years) and the female predominance of GCA in our group of patients with positive TA biopsy (62.5%) was like other reports. In our study 22.9% of performed TA biopsies over the period of the study were positive confirming the diagnosis of GCA on histological exam, which was similar to another report and is considered to be relatively low. The incorporation of increased clinically focused assessments and algorithms, with the aid of the ACR/EULAR criteria, may decrease the frequency of TA biopsies that carries unnecessary cost and risk of procedure-related morbidity. We highly recommend applying the age of ≥ 50 years as an initial criterion for diagnosis, followed by the consideration of the statistically significant clinical features: scalp tenderness, jaw claudication, and optic nerve pallor.

Estimating overdiagnosis in giant cell arteritis diagnostic pathways using genetic data: genetic association study

OBJECTIVES

Giant cell arteritis (GCA) may be confirmed by temporal artery biopsy (TAB) but false negatives can occur. GCA may be overdiagnosed in TAB-negative cases, or if neither TAB nor imaging is done. We used Human Leucocyte Antigen (HLA) genetic association of TAB-positive GCA as an "unbiased umpire" test to estimate historic overdiagnosis of GCA.

METHODS

Patients diagnosed with GCA between 1990-2014 were genotyped. During this era, vascular imaging alone was rarely used to diagnose GCA. HLA region variants were jointly imputed from genome-wide genotypic data of cases and controls. Per-allele frequencies across all HLA variants with p< 1.0x1 0 -5 were compared with population control data to estimate overdiagnosis rates in cases without a positive TAB.

RESULTS

Genetic data from 663 GCA patients were compared with data from 2619 population controls. TAB-negative GCA (n = 147) and GCA without TAB result (n = 160) had variant frequencies intermediate between TAB-positive GCA (n = 356) and population controls. For example, the allele frequency of HLA-DRB1*04 was 32% for TAB-positive GCA, 29% for GCA without TAB result, 27% for TAB-negative GCA and 20% in population controls. Making several strong assumptions, we estimated that around two-thirds of TAB-negative cases and one-third of cases without TAB result may have been overdiagnosed. From these data, TAB sensitivity is estimated as 88%.

CONCLUSIONS

Conservatively assuming 95% specificity, TAB has a negative likelihood ratio of around 0.12. Our method for utilising standard genotyping data as an "unbiased umpire" might be used as a way of comparing the accuracy of different diagnostic pathways.

Mycophenolate mofetil in giant cell arteritis

Introduction

Giant cell arteritis (GCA) is a systemic granulomatous vasculitis affecting the large arteries. Abnormal lymphocyte function has been noted as a pathogenic factor in GCA. Mycophenolate mofetil (MMF) inhibits inosine monophosphate dehydrogenase and is therefore a highly lymphocyte-specific immunosuppressive therapy. We aimed to assess the efficacy of MMF for inducing remission in GCA.

Methods

Seven patients (5 female, 2 male) with GCA under therapy with MMF and who were treated at the outpatient clinic for rare inflammatory systemic diseases at Hannover Medical School between 2010 and 2023 were retrospectively included in the study. All patients underwent duplex sonography, 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET), magnetic resonance imaging (MRI), and/or biopsy to confirm the diagnosis. The primary endpoints were the number of recurrences, CRP levels at 3-6 and 6-12 months, and the period of remission.

Results

All patients in this case series showed inflammatory activity of the arterial vessels in at least one of the imaging modalities: duplex sonography (n = 5), 18F-FDG PET (n = 5), MRI (n = 6), and/or biopsy (n = 5). CRP levels of all patients decreased at the measurement time points 3-6 months, and 6-9 months after initiation of therapy with MMF compared with CRP levels before MMF therapy. All patients with GCA in this case series achieved disease remission.

Discussion

The results of the present case series indicate that MMF is an effective therapy in controlling disease activity in GCA, which should be investigated in future randomized controlled trials.

Does the halo count on temporal and axillary ultrasound predict time to relapse in giant cell arteritis?

OBJECTIVES

To determine whether the halo count (HC) on temporal and axillary artery US (TAUS) predicts time to relapse in giant cell arteritis (GCA).

METHODS

We conducted a single-centre retrospective study of GCA patients. HC, the number of vessels with non-compressible halo on the TAUS at diagnosis, was determined by retrospective review of the US report and images. Relapse was defined as increase in GCA disease activity requiring treatment escalation. Cox proportional hazard regression was used to identify predictors of time to relapse.

RESULTS

A total of 72 patients with confirmed GCA were followed up for a median of 20.9 months. Thirty-seven of 72 (51.4%) relapsed during follow-up, at a median prednisolone dose of 9 mg (range 0-40 mg). Large-vessel (axillary artery) involvement did not predict relapse. On univariable analysis, a higher HC was associated with shorter time to relapse (per-halo hazard ratio 1.15, 95% CI 1.02, 1.30; P = 0.028). However, statistical significance was lost when the 10 GCA patients with an HC of zero were excluded from analysis.

CONCLUSION

In this real-world setting, relapse occurred at a wide range of glucocorticoid doses and was not predicted by axillary artery involvement. GCA patients with a higher HC at diagnosis were significantly more likely to relapse, but significance was lost on excluding those with HC of zero. HC is feasible in routine care and may be worth incorporating into future prognostic scores. Further research is required to determine whether confirmed GCA patients with negative TAUS represent a qualitatively different subphenotype within the GCA disease spectrum.

Age-related histopathological findings in temporal arteries

AIMS

Giant cell arteritis (GCA) is a systemic vasculitis affecting medium and large arteries in patients aged over 50 years. Involvement of temporal arteries (TA) can lead to complications such as blindness and stroke. While the diagnostic gold standard is temporal artery biopsy (TAB), comorbidities and age-related changes can make interpretation of such specimens difficult. This study aims to establish a baseline of TA changes in subjects without GCA to facilitate the interpretation of TAB.

METHODS AND RESULTS

Bilateral TA specimens were collected from 100 consecutive eligible postmortem examinations. Subjects were divided into four age groups and specimens semiquantitatively evaluated for eccentric intimal fibroplasia, disruption and calcification of the internal elastic lamina (IEL), medial attenuation and degree of lymphocytic inflammation of the peri-adventitia, adventitia, media and intima. The individual scores of intimal fibroplasia, IEL disruption and medial attenuation were added to yield a 'combined score (CS)'. Seventy-eight 78 decedents were included in the final analysis following exclusion of 22 individuals for either lack of clinical information or inability to collect TA tissue. A total of 128 temporal artery specimens (50 bilateral from individual decedents, 28 unilateral) were available for examination. Intimal proliferation, IEL loss, IEL calcification and CS increased with age in a statistically significant fashion. Comparison of the oldest age group with the others showed statistically significant differences, although this was not uniformly preserved in comparison between the three youngest groups.

CONCLUSION

Senescent arterial changes and healed GCA exhibit histological similarity and such changes increase proportionally with age. The CS demonstrates significant association with age overall and represents a potential avenue for development to 'normalise' TA biopsies from older individuals.

Temporal artery biopsy for suspected giant cell arteritis: A mini review

Giant cell arteritis (GCA) is a granulomatous inflammation involving medium and large vessels that can lead to serious clinical manifestations associated with tissue ischemia. Temporal artery biopsy (TAB) is currently the gold standard method for the diagnosis of GCA, with a specificity of 100% and a sensitivity of 77%. However, the false-negative rate for TAB ranges from 9% to 61%. False negatives may be related to the timing of biopsy, the length of specimen, and the existence of "skip lesions." We reviewed the relevant evidence for methods to improve the sensitivity and reduce the false-negative rate for TAB. To reduce the false-negative rate for TAB, it is recommended to perform TAB within 1 week of starting corticosteroid therapy. Although there is currently no consensus, we suggest that the temporal artery is cut to a length of 20‒30 mm and to prepare serial pathological sections. It is necessary to attach great importance to patients suspected of having GCA, and complete TAB should be performed as soon as possible while starting corticosteroid therapy promptly. We also discuss the clinical value of non-invasive vascular imaging technologies, such as DUS, CTA, MRA, and 18F-FDG-PET/CT, as auxiliary methods for GCA diagnosis that could partially replace TAB.

[Imaging of large vessel vasculitis]

Giant cell arteritis (GCA) and Takayasu arteritis (TAK) are the most important primary large vessel vasculitides. A rapid and reliable confirmation of the diagnosis is necessary to prevent ischemic complications. Patients with extracranial GCA and TAK often present with unspecific symptoms. Since 2018 the EULAR has recommended imaging as an alternative to histology for confirming the diagnosis. Ultrasound is particularly recommended as the primary imaging modality for cranial GCA. Alternatively, MRI and PET can be used for the diagnostics of temporal arteritis. Ultrasound is also valuable for extracranial GCA, alternatively MRI, CT or PET-CT can be used. This review discusses the current status of imaging techniques in large vessel vasculitis as well as the advantages and disadvantages. The focus is on ultrasound, which is increasingly being used as the primary diagnostic modality due to its excellent diagnostic quality, wide availability, noninvasiveness, and patient friendliness. Technical aspects, prerequisites, and normal and pathological findings are also presented. Finally, an outlook is given on promising new developments, such as scores for evaluating disease progression and contrast-enhanced ultrasound.

MR and CT angiography in the diagnosis of vasculitides

Vasculitides represent the wide-ranging series of complex inflammatory diseases that involve inflammation of blood vessel walls. These conditions are characterized according to the caliber of the predominantly involved vessels. The work-up of vasculitides often includes imaging to narrow a differential diagnosis and guide management. Findings from CT and MR angiography in conjunction with a thorough history and physical exam are of utmost importance in making an accurate diagnosis. Further, imaging can be used for follow-up, in order to monitor disease progression and response to treatment. This wide-ranging literature review serves as the primary resource for clinicians looking to diagnose and monitor the progression of rare vascular inflammatory conditions. This article provides a comprehensive summary of the main findings on imaging related to each of these vasculitides. For each of the named vasculitis conditions, a thorough overview of the diagnostic modalities and their respective findings is described. Many specific hallmarks of pathology are included in this review article.

The Role of Imaging in Diagnosis and Monitoring of Large Vessel Vasculitis

Technological advances and increased recognition of the prevalence and implications of large vessel vasculitis have led to robust research into various imaging techniques. Although there is still debate about which modality to choose in specific clinical scenarios, Ultrasound, PET/CT, MRI/A, and CT/A offer complementary information regarding diagnosis, disease activity, and vascular complication monitoring. Recognition of the strengths and limitations of each technique is important for appropriate application in clinical practice.

Giant cell arteritis: reviewing the advancing diagnostics and management

Giant Cell Arteritis (GCA) is well known to be a critical ischaemic disease that requires immediate medical recognition to initiate treatment and where one in five people still suffer visual loss. The immunopathophysiology has continued to be characterised, and the influencing of ageing in the development of GCA is beginning to be understood. Recent national and international guidelines have supported the directed use of cranial ultrasound to reduce diagnostic delay and improve clinical outcomes. Immediate high dose glucocorticoids remain the standard emergency treatment for GCA, with a number of targeted agents that have been shown in clinical trials to have superior clinical efficacy and steroid sparing effects. The aim of this review was to present the latest advances in GCA that have the potential to influence routine clinical practice.

Temporal Artery Ultrasound for the Diagnosis of Giant Cell Arteritis in the Emergency Department

Giant cell arteritis (GCA), known as temporal arteritis, is a serious condition requiring immediate treatment to prevent complications. GCA can be difficult to diagnose, especially in emergency department (ED) settings where ophthalmology and rheumatology services may be unavailable. Temporal artery ultrasound (TAUS) is a valuable tool for diagnosing GCA. In the ED, TAUS can be used to quickly rule out GCA and avoid unindicated steroid treatment, which can cause serious morbidity in elderly patients. This article discusses the use of TAUS for evaluating patients with suspected GCA in the ED and its potential to expedite treatment and ensure appropriate, timely follow-up for patients with this potential vision and life-threatening condition.

Role of Temporal artery biopsy in a sequential Giant Cell Arteritis fast-track pathway: a 5-year prospective study

BACKGROUND

Increasing number of centres are establishing sequential fast track pathways (FTP) for management of giant cell arteritis (GCA), with temporal artery ultrasound (US) replacing temporal artery biopsy (TAB) as the first investigational method. Biopsy is performed as second investigation, when US is negative/inconclusive. This study investigates the role of TAB in a sequential GCA-FTP and its utility in those with negative/inconclusive US.

METHODS

Prospective study of patients referred for TAB as part of Coventry sequential GCA-FTP May 2014-June 2019. Analysis included sensitivity and specificity of TAB, impact of arterial specimen length and duration of treatment with corticosteroids on sensitivity of TAB and the clinical predictors for a positive biopsy.

RESULTS

A total of 1149 patients with suspected GCA were referred to this GCA-FTP, with 109 (9.5%) referred for TAB. Overall sensitivity of TAB was 47% (specificity: 100%) and in patients with negative/inconclusive US sensitivity was 39% (specificity:100%). Post-fixation arterial specimen length <15 mm showed lower sensitivity (14%), which increased to 52% when specimen length was ≥15 mm. Sensitivity of TAB was highest in first 7 (60%) to 10 days (59%) from starting corticosteroids. Predictors of positive biopsy using univariate logistic regression analysis were jaw claudication (OR = 5.40; p = 0.0057), elevated erythrocyte sedimentation rate (OR = 5.50; p = 0.013) and elevated C-reactive protein (OR = 23.7; p = 0.0043).

CONCLUSION

This is the first study to look at the role of TAB in a sequential GCA-FTP. Biopsy plays an important role in GCA-FTP, when US is negative/inconclusive. Sensitivity of TAB improved when specimen length was ≥15 mm and performed within 10 days of commencing corticosteroids.

Diagnostic yield of combined cranial and large vessel PET/CT, ultrasound and MRI in giant cell arteritis: A systematic review and meta-analysis

OBJECTIVES

To estimate the diagnostic accuracy of combined cranial and large vessel imaging by PET/CT, ultrasound and MRI for giant cell arteritis (GCA).

METHODS

PubMed, Embase, Cochrane and Web of Science databases were searched from inception till August, 312,022. Studies were included if they involved patients with suspected GCA and assessed the diagnostic accuracy of combined cranial and large vessel imaging by PET/CT, ultrasound or MRI with the final clinical diagnosis as reference standard.

RESULTS

Eleven (1578 patients), 3 (149 patients) and 0 studies were included for the diagnostic accuracy of ultrasound, PET/CT and MRI, respectively. Combined cranial and large vessel ultrasound had a sensitivity of 86% (76-92%) and specificity of 96% (92-98%). PET/CT of both cranial and large vessels yielded a sensitivity of 82% (61-93%) and specificity of 79% (60-90%). No studies assessed both PET/CT and ultrasound, which precluded head-to-head comparison. Addition of large vessel ultrasound to ultrasound of the temporal arteries (7 studies) significantly increased sensitivity (91% versus 80%, p < 0.001) without decrease in specificity (96% versus 95%, p = 0.57). Evaluating cranial arteries in addition to large vessels on PET/CT (3 studies) tended to increase the sensitivity (82% versus 68%, p = 0.07) without decrease in specificity (81% versus 79%, p = 0.70).

CONCLUSION

Combined cranial and large vessel ultrasound and PET/CT provided excellent accuracy for the diagnosis of GCA. Either PET/CT or ultrasound may be preferred depending on setting, expertise and clinical presentation. The diagnostic accuracy of combined cranial and large vessel MRI needs to be determined in future studies.

Extended ultrasound examination identifies more large vessel involvement in patients with giant cell arteritis

OBJECTIVES

To compare limited with a more extended ultrasound examination (anteromedial ultrasound, A2-ultrasound) to detect large vessel (LV) involvement in patients with newly diagnosed GCA.

METHODS

Patients with new-onset GCA were included at the time of diagnosis. All patients were examined using limited ultrasound (ultrasound of the axillary artery as visualized in the axilla) and an extended A2-ultrasound method (which also includes the carotid, vertebral, subclavian and proximal axillary arteries), in addition to temporal artery ultrasound.

RESULTS

One hundred and thirty-three patients were included in the study. All patients fulfilled the criteria according to a proposed extension of the 1990 ACR classification criteria for GCA and had a positive ultrasound examination at diagnosis. Ninety-three of the 133 GCA patients (69.9%) had LV involvement when examined by extended A2-ultrasound, compared with only 56 patients (42.1%) by limited ultrasound (P < 0.001). Twelve patients (9.0%) had vasculitis of the vertebral arteries as the only LVs involved. Five patients (3.8%) would have been missed as having GCA if only limited ultrasound was performed. Forty patients (30.0%) had isolated cranial GCA, 21 patients (15.8%) had isolated large vessel GCA and 72 patients (54.1%) had mixed-GCA.

CONCLUSION

Extended A2-ultrasound examination identified more patients with LV involvement than the limited ultrasound method. However, extended A2-ultrasound requires high expertise and high-end equipment and should be performed by ultrasonographers with adequate training.

Fast-track pathway for early diagnosis and management of giant cell arteritis: the combined role of vascular ultrasonography and [18F]-fluorodeoxyglucose PET-computed tomography imaging

Giant cell arteritis (GCA) is a medical emergency, which can lead to irreversible blindness and other ischaemic vascular events if left untreated. Prompt access to specialist assessment, diagnostics in the form of a fast-track pathway (FTP) and access to appropriate treatment are key factors in preventing morbidity associated with this disease. Recent developments in vascular imaging prompted review of our management of GCA patients. Here, we present the newly implemented FTP in GCA at the University College London Hospital, with added vascular imaging in the form of temporal artery ultrasound (TAUS) and [18F]-fluorodeoxyglucose PET-computed tomography ( 18 F-FDG PET-CT) with temporal artery biopsy. The initial pilot data on the FTP showed a significant negative predictive value of the combined TAUS and 18 F-FDG PET-CT, and the vast majority of cases positive on imaging were confirmed by biopsy. Through the new FTP in GCA, the diagnosis was completed within 48-72 h, compared with the conventional pathway time of up to 2-3 weeks awaiting biopsy results. Prompt and accurate diagnosis of GCA enables commencement of corticosteroid (prednisolone) treatment in the appropriate patient population while avoiding unnecessary steroid exposure and toxicity in GCA-negative patients.

Diagnostic validity of ultrasound including extra-cranial arteries in giant cell arteritis

OBJECTIVES

Color Doppler ultrasound (CDUS) of the temporal arteries (TA) is becoming the first test to be performed for suspected giant cell arteritis (GCA). Our aim was to assess the added value of including CDUS of large vessels (LV) in the diagnosis of GCA.

METHODS

We performed an observational and retrospective study of consecutive patients with suspected GCA. Baseline CDUS of the TA and LV (axillary, subclavian, and carotid) were conducted. We defined the CDUS finding as positive if the halo sign was present.

RESULTS

Of 198 patients with suspected GCA, 87 were eventually diagnosed with GCA: 45 (51.7%) had a cranial pattern exclusively, 31 (35.6%) had both a cranial and an LV pattern, and 11 (12.6%) had an isolated LV pattern. CDUS of the TA had a sensitivity of 83.9%, specificity of 97.3%, and positive and negative predictive values (PPV, NPV) of 96.1% and 88.5%, respectively. When LV was added, sensitivity increased to 96.6% and NPV to 98.2%. Specificity was 97.3% and PPV was 96.6%. As for LVs, the axillary, subclavian, and carotid arteries were involved in 87.8%, 77.4%, and 34.4%, respectively. Isolated axillary examination resulted in a loss of 12.2% of patients with LV involvement; however, inclusion of the axillary and subclavian arteries retained 100% of patients with LV involvement.

CONCLUSIONS

Detection of GCA by ultrasound should routinely include examinations of the TA and LV (at least the axillary and subclavian arteries) to improve diagnostic accuracy. More than 12% of patients in our cohort had isolated LV involvement. Key Points • Extracranial involvement in GCA is very common: half of patients have extracranial vasculitis and more than 12% isolated LV involvement that can be demonstrated with CDUS. • Adding a CDUS examination of LV to TA increased sensitivity (from 83.9 to 96.6%) and the negative predictive value (from 88.5 to 98.2%) for diagnosis of GCA. • In our cohort, if we only examined the axillary arteries, 12.2% of the CGA with LV involvement would not have been diagnosed. • We propose a CDUS protocol that includes examination of the TA and LV (at least the axillary and subclavian arteries) routinely in cases of suspected GCA.

Imaging of giant cell arteritis - recent advances

Imaging is increasingly being used to guide clinical decision-making in patients with giant cell arteritis (GCA). While ultrasound has been rapidly adopted in fast-track clinics worldwide as an alternative to temporal artery biopsy for the diagnosis of cranial disease, whole-body PET/CT is emerging as a potential gold standard test for establishing large vessel involvement. However, many unanswered questions remain about the optimal approach to imaging in GCA. For example, it is uncertain how best to monitor disease activity, given there is frequent discordance between imaging findings and conventional disease activity measures, and imaging changes typically fail to resolve completely with treatment. This chapter addresses the current body of evidence for the use of imaging modalities in GCA across the spectrum of diagnosis, monitoring disease activity, and long-term surveillance for structural changes of aortic dilatation and aneurysm formation and provides suggestions for future research directions.

The role of autoimmunity and autoinflammation in giant cell arteritis: A systematic literature review

Giant cell arteritis is the most common form of large vessel vasculitis and preferentially involves large and medium-sized arteries in patients over the age of 50. Aggressive wall inflammation, neoangiogenesis and consecutive remodeling processes are the hallmark of the disease. Though etiology is unknown, cellular and humoral immunopathological processes are well understood. Matrix metalloproteinase-9 mediated tissue infiltration occurs through lysis of basal membranes in adventitial vessels. CD4+ cells attain residency in immunoprotected niches, differentiate into vasculitogenic effector cells and enforce further leukotaxis. Signaling pathways involve the NOTCH1-Jagged1 pathway opening vessel infiltration, CD28 mediated T-cell overstimulation, lost PD-1/PD-L1 co-inhibition and JAK/STAT signaling in interferon dependent responses. From a humoral perspective, IL-6 represents a classical cytokine and potential Th-cell differentiator whereas interferon-γ (IFN- γ) has been shown to induce chemokine ligands. Current therapies involve glucocorticoids, tocilizumab and methotrexate application. However, new agents, most notably JAK/STAT inhibitors, PD-1 agonists and MMP-9 blocking substances, are being evaluated in ongoing clinical trials.

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.

Accuracy of Doppler ultrasound in the diagnosis of giant cell arteritis: a systematic review and meta-analysis

BACKGROUND

Giant cell arteritis (GCA) is the most common primary systemic vasculitis in people 50 years of age and over, and it is considered a medical emergency due to the potential risk of permanent visual loss. Color Doppler ultrasound (CDU) of the temporal arteries is a rapid, noninvasive method to diagnose GCA. This study aims to determine the diagnostic accuracy of the halo sign in temporal arteries by CDU in people with suspected GCA.

METHODS

The systematic literature review included the search for publications in the following electronic databases: PubMed, Embase, CENTRAL, LILACS, WHO ICTRP, ClinicalTrials.gov, gray literature up to December 2022, and no date or language restrictions were applied. We analyzed studies including patients over 50 years of age with suspected GCA evaluating CDU of temporal arteries as a diagnostic tool against clinical diagnosis as a standard reference. Paper titles and abstracts were selected by two investigators independently for all available records. The quality of the studies was assessed using the Quality of Diagnostic Accuracy Studies tool (QUADAS-2) and the R software (version 4.2.1) was used for data analysis. The protocol of this review is registered with PROSPERO (CRD42016033079).

RESULTS

Twenty-two studies including 2893 participants with suspected GCA who underwent temporal artery CDU were evaluated. The primary analysis results showed a sensitivity of 0.76 [95% confidence interval (95 CI) 0.69-0.81] and specificity of 0.93 (95 CI 0.89-0.95) when the halo sign was compared to clinical diagnosis. The sensitivity value of 0.84 (95 CI 0.72-0.92) and specificity of 0.95 (95 CI 0.88-0.98) were found in five studies involving 1037 participants that analyzed the halo sign and temporal artery compression sign. A sensitivity of 0.86 (95 CI 0.78-0.91) and specificity of 0.95 (95 CI 0.89-0.98) were found in four studies with 603 participants where the halo sign was evaluated CDU on temporal and axillary arteries.

CONCLUSION

The detection of the halo sign by CDU of temporal arteries has good accuracy for the diagnosis of cranial GCA. The compression sign in temporal arteries and the addition of axillary arteries assessment improves the diagnostic performance of CDU for GCA.

TRIAL REGISTRATION

PROSPERO CRD42016046860.

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.

Comparison of temporal artery ultrasound versus biopsy in the diagnosis of giant cell arteritis

BACKGROUND/OBJECTIVES

Giant cell arteritis (GCA) is a medical and ophthalmological emergency due to risk of stroke and sudden irreversible loss of vision. Fast and accurate diagnosis is important to prevent complications and long-term high dose glucocorticoids toxicity. Temporal artery biopsy is gold standard for diagnosing GCA. However, temporal artery ultrasound is a fast and non-invasive procedure which may provide a supplement or an alternative to biopsy. This study assesses the diagnostic performance of ultrasound and biopsy in the diagnosis of GCA.

SUBJECTS/METHODS

Examination results of patients suspected of having GCA in the period from August 2018 to June 2019 were reviewed. Patients underwent clinical examination and blood tests. Within a few days of starting glucocorticoid treatment, temporal ultrasound and unilateral biopsy were performed. Experienced physicians established the final clinical diagnosis at 6-months follow-up.

RESULTS

Seventy-eight patients underwent both ultrasound and biopsy. Thirty-five (45%) received the final clinical diagnosis of GCA. Compared with the final clinical diagnosis, biopsy had a sensitivity of 69% (51-83%) and a specificity of 100% (92-100%), and ultrasound a sensitivity of 63% (45-79%) and a specificity of 79% (64-94%). Area under the receiver operating characteristics curves were 0.84 and 0.71 for biopsy and ultrasound respectively (p = 0.048). False negative rate of ultrasound was 4 out of 78 (5%).

CONCLUSION

Sensitivity of ultrasound is almost on par with that of biopsy although the overall diagnostic accuracy of ultrasound was slightly lower. We find that ultrasound is a reliable tool for first line diagnosis of GCA.

Optimizing the use of temporal artery biopsy: a retrospective study

BACKGROUND

Giant cell arteritis is an inflammatory disease of the large- and medium-sized vessels. It is the most common primary vasculitis, with lifetime incidences of 0.5% and 1% in men and women, respectively. Its diagnosis is based upon clinical criteria, which may include temporal artery biopsy. Expected positivity rates of temporal artery biopsies and patient selection remain controversial topics in the literature.

METHODS

A cross-sectional retrospective study of 127 patients referred for temporal artery biopsy with a diagnosis of suspected giant cell arteritis between January 2014 and December 2018 was performed. The primary outcome was the positivity rate. The relationships between positivity rates, symptoms, clinical suspicion, biopsy delay, biopsy length and corticosteroid treatment were also studied.

RESULTS

A positivity rate of 23.7% (16.6-32.6%) was shown, along with a significant association between jaw claudication and specimen positivity (odds ratio 8.1, p < 0.05). Moreover, there were significant associations between a high initial clinical suspicion of disease and specimen positivity (p < 0.05), as well as a high initial clinical suspicion of disease and pursuit of corticosteroid treatment following biopsy results, regardless of positivity (p < 0.05). The duration of corticosteroid treatment prior to biopsy was not associated with a change in positivity rate.

CONCLUSIONS

The positivity rate of temporal artery biopsy was 23.7%. Treatment of patients with negative temporal artery biopsy was associated with maintenance of corticosteroid treatment when the initial clinical suspicion of arteritis was high. Therefore, temporal artery biopsy may not be necessary for patients with a high initial clinical suspicion of giant cell arteritis.

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

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

Evaluation of Arterial Histopathology and microRNA Expression That Underlie Ultrasonography Findings in Temporal Arteries of Patients with Giant Cell Arteritis

The aim of this study was to assess the interrelation between vascular ultrasonography (US) findings, histopathological data, and the expression of selected dysregulated microRNAs (miRNAs) in giant cell arteritis (GCA). The study included data on the clinical parameters, US measurements, and temporal artery biopsies (TABs) of 46 treatment-naïve patients diagnosed with GCA and 22 age-matched non-GCA patient controls. We performed a comprehensive comparative and correlation analysis along with generation of receiver operating characteristic (ROC) curves to ascertain the diagnostic performance of US examination parameters and selected miRNAs for GCA diagnosis. We showed significant differences in the US-measured intima-media thickness of the temporal arteries, the presence of a halo sign, and the presence of luminal stenosis between GCA-positive/TAB-positive, GCA-positive/TAB-negative, and non-GCA patients. Correlation analysis revealed significant associations between several histopathological parameters, US-measured intima-media thickness, and the halo sign. We found that the significant overexpression of miR-146b-5p, miR-155-5p, miR-511-5p, and miR-21-5p, and the under-expression of the miR-143/145 cluster, miR-30a-5p, and miR-125a-5p, coincides and is associated with the presence of a halo sign in patients with GCA. Notably, we determined a high diagnostic performance of miR-146b-5p, miR-21-3p, and miR-21-5p expression profiles in discriminating GCA patients from non-GCA controls, suggesting their potential utilization as putative biomarkers of GCA. Taken together, our study provides an insight into the US-based diagnostic evaluation of GCA by revealing the complex interrelation of clearly defined image findings with underlying vascular immunopathology and altered arterial tissue-specific miRNA profiles.

Validating the Clinical Value of Temporal Artery Biopsy

BACKGROUND

Giant cell arteritis (GCA) is a potentially devastating disease that may require treatment with high-dose steroids. Traditionally, diagnosis requires patients to meet at least 3 of 5 clinical criteria, one of which is a positive temporal artery biopsy (TAB). Vascular surgeons are often asked to perform TAB though it is not necessarily required for diagnosis or management. This study aimed to determine if TAB results altered management of patients with a concern for GCA by changing steroid use postoperatively in our health care system.

METHODS

A retrospective review at a single-center tertiary care hospital was performed between 2007 and 2018. The inclusion criteria were patients greater than 18 years old with complete steroid treatment records who underwent a temporal artery biopsy due to concern for GCA. Steroid use and duration of treatment both pre- and post-operative were collected and analyzed.

RESULTS

Eighty-three of 117 cases reviewed met inclusion criteria. Ninety-one percent (76) of patients had a negative biopsy. Twenty-nine percent (23) of negative biopsies met criteria for GCA prior to biopsy. Of those with a negative biopsy, steroids were continued in 68% (52) of patients after 30 days, 49% (37) after 90 days and 45% (34) after 180 days. Steroids were never started in 11% (6). One patient with a positive biopsy was discontinued on steroids due to intolerance. There was no statistically significant difference in duration of steroids between those with a positive and negative biopsy (average 610 and 787 days respectively; P = 0.682). Average follow up was 33 months.

DISCUSSION

The duration of steroid use for patients with concern for GCA was not found to be altered by the performance of a TAB at our institution. Given the extremely low yield and absence of impact on steroid duration, TAB is not a useful diagnostic test at our institution. Similar reviews are recommended to determine the utility of TAB at other institutions that may differ in patient population or prescribing practices.