Ultrasonography of the superficial temporal and axillary arteries in giant cell arteritis diagnosis

OBJECTIVES

Giant cell arteritis (GCA) is the main systemic vasculitis in individuals aged ≥ 50 years. Color Doppler ultrasound (CDS) has an established role in GCA diagnosis and management. This study aims to assess the clinical characteristics associated with a positive CDS evaluation and the impact of additional axillary artery examination on diagnostic sensitivity.

MATERIAL AND METHODS

We conducted a retrospective analysis of patients undergoing CDS of the superficial temporal arteries, with or without axillary artery assessment, at our hospital, between 2009 and 2023. Patients meeting the new 2022 diagnostic criteria for GCA were included and their characteristics were analyzed according to the presence of the halo sign on CDS.

RESULTS

Of the 135 included patients (54 % female, mean age 75 ± 8 years), the halo sign was observed in 57 %, correlating with higher systemic symptom prevalence (61 % vs 42 %, p = 0.035), lower hemoglobin (p < 0.001), and higher erythrocyte sedimentation rate (p = 0.028). The halo sign inversely related to prior corticosteroid therapy (p = 0.033). Patients with axillary halo sign had fewer external carotid symptoms and a higher vertebral halo sign prevalence. Vertebral halo sign was associated with posterior circulation ischemic stroke (65 %, p < 0.001). Axillary artery studies improved diagnostic sensitivity by 9 %.

CONCLUSION

In our study, the halo sign correlated with higher systemic symptoms and analytical abnormalities. Axillary artery examination enhanced CDS sensitivity, linked to severe outcomes like stroke. Prior corticosteroid therapy reduced CDS sensitivity. The correlation of clinical, laboratory, and ultrasound findings provides a more comprehensive understanding of GCA pathogenesis and evolution.

[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.

The spectrum of giant cell arteritis through a rheumatology lens

Treatment of giant cell arteritis (GCA) aims initially to prevent acute visual loss, and subsequently to optimise long-term quality of life. Initial prevention of acute visual loss in GCA is well-standardised with high-dose glucocorticoid therapy but in the longer term optimising quality of life requires tailoring of treatment to the individual. The licensing of the IL-6 receptor inhibitor tocilizumab combined with advances in vascular imaging have resulted in many changes to diagnostic and therapeutic practice. Firstly, GCA is a systemic disease that may involve multiple vascular territories and present in diverse ways. Broadening of the "spectrum" of what is called GCA has been crystallised in the 2022 GCA classification criteria. Secondly, the vascular inflammation of GCA frequently co-exists with the extracapsular musculoskeletal inflammation of the related disease, polymyalgia rheumatica (PMR). Thirdly, GCA care must often be delivered across multiple specialities and healthcare organisations requiring effective interprofessional communication. Fourthly, both GCA and PMR may follow a chronic or multiphasic disease course; long-term management must be tailored to the individual patient's needs. In this article we focus on some areas of current rheumatology practice that ophthalmologists need to be aware of, including comprehensive assessment of extra-ocular symptoms, physical signs and laboratory markers; advanced imaging techniques; and implications for multi-speciality collaboration.

Diagnosing vasculitis with ultrasound: findings and pitfalls

Rheumatologists are increasingly utilizing ultrasound for suspected giant cell arteritis (GCA) or Takayasu arteritis (TAK). This enables direct confirmation of a suspected diagnosis within the examination room without further referrals. Rheumatologists can ask additional questions and explain findings to their patients while performing ultrasound, preferably in fast-track clinics to prevent vision loss. Vascular ultrasound for suspected vasculitis was recently integrated into rheumatology training in Germany. New European Alliance of Associations for Rheumatology recommendations prioritize ultrasound as the first imaging tool for suspected GCA and recommend it as an imaging option for suspected TAK alongside magnetic resonance imaging, positron emission tomography and computed tomography. Ultrasound is integral to the new classification criteria for GCA and TAK. Diagnosis is based on consistent clinical and ultrasound findings. Inconclusive cases require histology or additional imaging tests. Robust evidence establishes high sensitivities and specificities for ultrasound. Reliability is good among experts. Ultrasound reveals a characteristic non-compressible 'halo sign' indicating intima-media thickening (IMT) and, in acute disease, artery wall oedema. Ultrasound can further identify stenoses, occlusions and aneurysms, and IMT can be measured. In suspected GCA, ultrasound should include at least the temporal and axillary arteries bilaterally. Nearly all other arteries are accessible except the descending thoracic aorta. TAK mostly involves the common carotid and subclavian arteries. Ultrasound detects subclinical GCA in over 20% of polymyalgia rheumatica (PMR) patients without GCA symptoms. Patients with silent GCA should be treated as GCA because they experience more relapses and require higher glucocorticoid doses than PMR patients without GCA. Scores based on intima-thickness (IMT) of temporal and axillary arteries aid follow-up of GCA, particularly in trials. The IMT decreases more rapidly in temporal than in axillary arteries. Ascending aorta ultrasound helps monitor patients with extracranial GCA for the development of aneurysms. Experienced sonologists can easily identify pitfalls, which will be addressed in this article.

EULAR recommendations for the use of imaging in large vessel vasculitis in clinical practice: 2023 update

OBJECTIVES

To update the EULAR recommendations for the use of imaging modalities in primary large vessel vasculitis (LVV).

METHODS

A systematic literature review update was performed to retrieve new evidence on ultrasound, MRI, CT and [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) for diagnosis, monitoring and outcome prediction in LVV. The task force consisted of 24 physicians, health professionals and patients from 14 countries. The recommendations were updated based on evidence and expert opinion, iterating until voting indicated consensus. The level of agreement was determined by anonymous votes.

RESULTS

Three overarching principles and eight recommendations were agreed. Compared to the 2018 version, ultrasound is now recommended as first-line imaging test in all patients with suspected giant cell arteritis, and axillary arteries should be included in the standard examination. As an alternative to ultrasound, cranial and extracranial arteries can be examined by FDG-PET or MRI. For Takayasu arteritis, MRI is the preferred imaging modality; FDG-PET, CT or ultrasound are alternatives. Although imaging is not routinely recommended for follow-up, ultrasound, FDG-PET or MRI may be used for assessing vessel abnormalities in LVV patients with suspected relapse, particularly when laboratory markers of inflammation are unreliable. MR-angiography, CT-angiography or ultrasound may be used for long-term monitoring of structural damage, particularly at sites of preceding vascular inflammation.

CONCLUSIONS

The 2023 EULAR recommendations provide up-to-date guidance for the role of imaging in the diagnosis and assessment of patients with LVV.

Headache attributed to giant cell arteritis complicated with rheumatic polymyalgia diagnosed with F18-fluorodeoxyglucose positron emission tomography and computed tomography: a case report

Giant cell arteritis (GCA) is a kind of systemic vasculitis affecting individuals over 50 years old and is often the cause of new-onset headaches in older adults. Patients with GCA sometimes have rheumatic polymyalgia (PMR). The diagnosis of GCA generally depends on clinical manifestation, elevated erythrocyte sedimentation rate (ESR) or C-reactive protein, and positive imaging findings commonly obtained by ultrasound or temporal artery biopsy. In this study, we report a case of an 83-year-old woman with a new-onset headache and an elevated ESR. The result of the temporal artery ultrasound did not distinguish between vasculitis and atherosclerosis. The F18-fluorodeoxyglucose positron emission tomography and computed tomography (18F FDG PET-CT) were performed and suggested large vessel vasculitis with temporal artery involvement. In addition, polyarticular synovitis and bursitis were also revealed. Finally, the diagnosis of secondary headache attributed to CGA complicated with PMR was established. The patient experienced remission of symptoms after glucocorticoid therapy. PET can become a powerful tool for diagnosis and differential diagnosis when the ultrasound result is ambiguous and a biopsy is not obtained.

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.

Giant Cell Arteritis: State of the Art in Diagnosis, Monitoring, and Treatment

Giant cell arteritis (GCA) is the most prevalent subtype of vasculitis in adults. In recent years, there has been substantial improvement in the diagnosis and treatment of GCA, mainly attributed to the introduction of highly sensitive diagnostic tools, incorporation of modern imaging modalities for diagnosis and monitoring of large-vessel vasculitis, and introduction of highly effective novel biological therapies that have revolutionized the field of GCA. This article reviews state-of-the-art approaches for the diagnosis, monitoring, and treatment options of 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.

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.

Vaskulitis mimics

Idiopathische Vaskulitiden sind seltene entzündliche Systemerkrankungen, die nach der Chapel-Hill Konsensus-Nomenklatur nach der Größe der prädominant betroffenen Gebiete von Blutgefäßen (große, mittelgroße, kleine Gefäße und Gefäße variabler Größe) eingeteilt werden. Vaskulitis mimics sind Syndrome, die ein ähnliches klinisches Bild hervorrufen oder leicht mit einer idiopathischen Vaskulitis verwechselt werden und teils sogar ein Krankheitsbild, das klinisch und histologisch einer Vaskulitis gleicht, auslösen können. Die Zahl der Vaskulitis mimics ist groß, je nach betroffenem Gefäßgebiet kommen hereditäre Erkrankungen des Bindegewebes, genetisch bedingte Immundefekt- und Autoinflammationssyndrome, infektiöse Erkrankungen, seltene entzündliche Systemerkrankungen, Tumorerkrankungen, medikamenteninduzierte Syndrome und zahlreiche weitere infrage. In diesem Review wird eine Auswahl klassischer Imitatoren von Vaskulitiden, orientiert an der Größe der betroffenen Blutgefäße präsentiert und Konstellationen, die typische „Fallstricke“ in der klinischen Abklärung darstellen können, diskutiert.

Can a Giant Cell Arteritis (GCA) Risk Stratification Score Be Helpful in Clinical Practice?

INTRODUCTION

Giant cell arteritis (GCA) is the most common type of large vessel vasculitis. The diagnosis of GCA is often challenging and there is a difficult balance of over- and underinvestigation. There have been several proposed scoring systems to help clinicians risk stratify patients who may present with suspected GCA.

METHODS

A retrospective cohort study was performed using electronic medical records of patients referred for a temporal artery biopsy (TAB) and temporal artery ultrasound scan (USS) for suspected GCA. All TABs performed at the Royal Wolverhampton NHS Trust between June 2014 and June 2018 and all USS procedures performed between January 2015 and January 2019 were analysed. Patients who undergo a USS for suspected GCA at our centre routinely have scanned bilateral temporal and axillary arteries. Patients were excluded if they already had a previous diagnosis of GCA (and the clinical question was suspected flare), or if there was insufficient information available.

RESULTS

The total number of patients who underwent a confirmatory diagnostic test (either TAB or USS) for suspected GCA was 187. Thirteen of these patients met the exclusion criteria, the remaining 174 patients were included for analysis. A total of 126 of 174 patients underwent a TAB and 63 of 174 had a USS performed; 15 of 174 who had both these were included in the USS cohort because for all these patients, the ultrasound was the first diagnostic test performed. Our results appear to closely mirror the original multi-centre results with regard to the prediction of biopsy-positive GCA, with the centiles closely following those in the inception cohort. Also, 0% of the 'low' risk probability biopsy cohort were misclassified; none had a positive biopsy. However, 8% of the low-risk-probability ultrasound cohort were misclassified, as two had a positive ultrasound.

CONCLUSION

 Our study highlights that a probability score for GCA derived from a large multi-centre cohort of patients who were biopsy positive predicts ultrasound positivity with similar accuracy. Our work reveals that scoring systems are not infallible but can be helpful in guiding clinical decision making.

Comparison of halo and compression signs assessed by a high frequency ultrasound probe for the diagnosis of Giant Cell Arteritis

OBJECTIVE

To evaluate the diagnosis performances of halo and compression signs alone and combined, assessed by a high frequency 22-MHz probe, and test their agreement in giant cell arteritis (GCA).

METHODS

In this cross-sectional study on patients suspected with GCA, halo sign was defined as hypo or iso-echogenic circumferential aspect of the vessel wall in transverse or longitudinal view; and compression sign was defined as visibility of the vessel wall upon transducer-imposed compression of the artery. Agreement of the two signs was tested using the Cohen's kappa statistic.

RESULTS

A total of 80 patients (50% women) were included with a mean age of 74.4 years. Twenty participants (25%) were ultimately treated for GCA. Halo and compression signs have respective prevalences of 35% and 48%, with respective sensitivity and specificity of 80% and 80% for the halo sign; and 85% and 65% for the compression sign. The kappa coefficient for the global agreement of the two signs was 0.67 (95% confident interval: 0.54-0.85). Combination of the two signs give a sensitivity of 80% and a specificity of 81.7%.

CONCLUSION

Halo and compression signs assessed by a high frequency probe, show a good level of agreement for the diagnosis of GCA and improve ultrasound specificity when combined together.

Impact of cardiovascular risk on the diagnostic accuracy of the ultrasound Halo Score for giant cell arteritis

OBJECTIVE

To evaluate the impact of cardiovascular risk (CVR) on the diagnostic accuracy of the ultrasonographic (US) Halo Score in patients with suspected giant cell arteritis (GCA).

METHODS

Retrospective observational study of patients referred to our US fast track clinic with suspected GCA for a 2-year period. The intima-media thickness (IMT) of cranial and extra-cranial arteries and the Halo Score was determined to assess the extent of vascular inflammation. The European Society of Cardiology Guidelines on CV Disease Prevention were used to define different categories of CVR and patients were classified according to the Systemic Coronary Risk Evaluation (SCORE). The gold standard for GCA diagnosis was clinical confirmation after a 6-month follow-up.

RESULTS

Of the 157 patients included, 47 (29.9%) had GCA after a 6-month follow-up. Extra-cranial artery IMT was significantly higher in patients with high/very high CVR than in those with low/moderate CVR, but only among patients without GCA. Non-GCA patients with high/very high CVR had also a significantly higher Halo Score in contrast with low/moderate CVR [9.38 (5.93) vs 6.16 (5.22); p = 0.007]. The area under the ROC curve of the Halo Score to identify GCA was 0.835 (95% CI 0.756-0.914), slightly greater in patients with low/moderate CVR (0.965 [95% CI 0.911-1]) versus patients with high/very high CVR (0.798 [95% CI 0.702-0.895]). A statistically weak positive correlation was found between the Halo Score and the SCORE (r 0.245; c = 0.002).

CONCLUSIONS

Elevated CVR may influence the diagnostic accuracy of the US Halo Score for GCA. Thus, CVR should be taken into consideration in the US screening for GCA.

Giant Cell Arteritis: Focusing on Current Aspects From the Clinic to Diagnosis and Treatment

Giant cell arteritis (GCA) is a granulomatous arteritis involving large arteries, particularly the aorta and its major proximal branches, including the carotid and temporal arteries. GCA involves individuals over 50 years old. The etiopathogenesis of GCA may involve a genetic background triggered by unknown environmental factors (eg infections), the activation of dendritic cells as well as inflammatory and vascular remodeling. However, its pathogenetic mechanism still remains unclear, although progress has been made in recent years. In the past, inflammatory markers and arterial biopsy were considered as gold standard for the diagnosis of GCA. However, emerging imaging methods have been made more sensitive and specific for the diagnosis of GCA. Treatment includes biological and other modalities including interleukin-6 (IL-6) inhibitors.

Ultrasound intima media thickness cut-off values for cranial and extracranial arteries in patients with suspected giant cell arteritis

Objective

To determine the optimal ultrasound (US) cut-off values for cranial and extracranial arteries intima media thickness (IMT) to discriminate between patients with and without giant cell arteritis (GCA).

Methods

Retrospective observational study including patients referred to an US fast-track clinic. All patients underwent bilateral US examination of the cranial and extracranial arteries including the IMT measurement. Clinical confirmation of GCA after 6 months was considered the gold standard for diagnosis. A receiver operating characteristic (ROC) analysis was performed to select the cut-off values on the basis of the best tradeoff values between sensitivity and specificity.

Results

A total of 157 patients were included, 47 (29.9%) with clinical confirmation of GCA after 6 months. 41 (87.2%) of patients with GCA had positive US findings (61.7% had cranial and 44.7% extracranial involvement). The best threshold IMT values were 0.44 mm for the common temporal artery; 0.34 mm for the frontal branch; 0.36 mm for the parietal branch; 1.1 mm for the carotid artery and 1 mm for the subclavian and axillary arteries. The areas under the ROC curves were greater for axillary arteries 0.996 (95% CI 0.991-1), for parietal branch 0.991 (95% CI 0.980-1), for subclavian 0.990 (95% CI 0.979-1), for frontal branch 0.989 (95% CI 0.976-1), for common temporal artery 0.984 (95% CI 0.959-1) and for common carotid arteries 0.977 (95% CI 0.961-0.993).

Conclusion

IMT cut-off values have been identified for each artery. These proposed IMT cut-off values may help to improve the diagnostic accuracy of US in clinical practice.

The Role of Ultrasound and FDG-PET/CT to Detect Extracranial Artery Involvement in Patients with Suspected Large Vessel Vasculitis

OBJECTIVE

To assess the accuracy of ultrasound (US) versus FDG-PET/CT to identify extracranial involvement in suspected large vessel vasculitis (LVV) patients.

METHODS

Retrospective observational study of patients referred to our US fast track clinic with suspected LVV. All patients underwent US exam within 24 hours per protocol. FDG-PET/CT was performed according to clinician criteria. The gold standard for LVV diagnosis was clinical confirmation after 6 months.

RESULTS

Of the 113 patients included (74.3% female, mean age 74 years), 37(32.7%) were diagnosed of LVV after 6 months. Sensitivity and specificity of US was 86.5% and 96.1%, respectively (85.7% and 87.1% for intracranial and 94.1% and 80.2% for extracanial arteries, respectively). Only 12(42.9%) of 28 patients undergoing a FDG-PET/CT per clinician criteria, showed positive findings. Sensitivity and specificity of FDG-PET/CT for LVV was 61.1% and 90%, respectively (55.6% and 63.2% for intracranial and 84.6% and 93.3% for extacranial arteries). Taking FDG-PET/CT as the reference, US showed extracranial inflammation in 10/12(83.3%) and detected 2(12.5%) additional cases of extracranial involvement with negative FDG-PET/CT. Conversely, FDG-PET/CT showed extracranial inflammation in 2 patients with negative US (1 isolated aortitis and 1 aortoiliac involvement). FDG-PET/CT showed cranial artery uptake in none of patients.

CONCLUSIONS

US and FDG-PET/CT are both valid tools to detect extracranial involvement. Presence of US extracranial artery inflammation is consistent with FDG-PET/CT examination, although a negative US scan does not rule out extracranial involvement. Our data support the use of US as first-line investigation in patients suspected of cranial, but also extracranial LVV.

Validity of the EULAR recommendations on the use of ultrasound in the diagnosis of giant cell arteritis

Objectives

The European Alliance of Associations for Rheumatology (EULAR) recommendations for the use of imaging in large vessel vasculitis establish that an imaging test supported by clinical pretest probability (PTP) is sufficient for the diagnosis of giant cell arteritis (GCA). Our objective was to determine the validity of the EULAR recommendations on the use of Colour duplex ultrasound (CDUS) in GCA after calculating the PTP.

Methods

We collected data of all patients referred to our fast-track clinic between 2016 and 2020. The Southend pretest probability score (SPTPS) was calculated and classified as low (LR), intermediate and high risk (HR) according to the values obtained by its authors, <9, 9–12 and >12, respectively. All patients underwent a CDUS of the temporal arteries with their common, parietal and frontal branches, and the most also axillary (86.5%), and subclavian and carotid arteries. The gold-standard diagnosis was made according to the physician’s criteria after at least 9 months of follow-up.

Results

Of the 297 referred patients, 97 (32.7%) were diagnosed with GCA. The SPTPS area under the ROC curve was 0.787. The LR category included 105 patients (35.4%), of which 10 (9.5%) had GCA and 1 had a CDUS false negative result. The HR category included 67 patients (22.5%), 47 with GCA, and in 1 case the CDUS result was a false positive.

Conclusion

Combining the results of a PTP score, such as SPTPS, and the CDUS allows for an accurate diagnosis of GCA, as established by the EULAR group, with less than 2% misclassification of diagnosis.

Cranial giant cell arteritis mimickers: A masquerade to unveil

Giant cell arteritis (GCA) is a large-vessel vasculitis that affects cranial and extra-cranial arteries. Extra-cranial GCA presents mainly with non-specific symptoms and the differential diagnosis is very broad, while the cranial form has more typical clinical picture and physicians have a lower threshold for diagnosis and treatment. Although temporal artery biopsy (TAB) has an established role, ultrasound (US) is being increasingly used as the first-line imaging modality in suspected GCA. Vasculitides (especially ANCA-associated), hematological disorders (mainly amyloidosis), neoplasms, infections, atherosclerosis and local disorders can affect the temporal arteries or might mimic the symptoms of cranial GCA and produce US and TAB findings that resemble those of temporal vasculitis. Given that prompt diagnosis is essential and proper treatment varies significantly among these diseases, in this review we aimed to collectively present disorders that can masquerade cranial GCA.

Temporal Artery Vascular Diseases

In the presence of temporal arteritis, clinicians often refer to the diagnosis of giant cell arteritis (GCA). However, differential diagnoses should also be evoked because other types of vascular diseases, vasculitis or not, may affect the temporal artery. Among vasculitis, Anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis is probably the most common, and typically affects the peri-adventitial small vessel of the temporal artery and sometimes mimics giant cell arteritis, however, other symptoms are frequently associated and more specific of ANCA-associated vasculitis prompt a search for ANCA. The Immunoglobulin G4-related disease (IgG4-RD) can cause temporal arteritis as well. Some infections can also affect the temporal artery, primarily an infection caused by the varicella-zoster virus (VZV), which has an arterial tropism that may play a role in triggering giant cell arteritis. Drugs, mainly checkpoint inhibitors that are used to treat cancer, can also trigger giant cell arteritis. Furthermore, the temporal artery can be affected by diseases other than vasculitis such as atherosclerosis, calcyphilaxis, aneurysm, or arteriovenous fistula. In this review, these different diseases affecting the temporal artery are described.

Colour Doppler ultrasound and the giant cell arteritis probability score for the diagnosis of giant cell arteritis: a Canadian single-centre experience

Objectives

The aim was to compare the accuracy of colour Doppler ultrasonography (CDUS) and temporal artery biopsy (TAB) to establish the final diagnosis of GCA and to determine how the GCA probability score (GCAPS) performs as a risk stratification tool.

Methods

Descriptive statistics were performed on a retrospective cohort of patients referred to our vasculitis referral centre between 1 July 2017 and 1 October 2020 for suspected GCA. CDUS, TAB, centre-specific TAB (vasculitis centre vs referring hospitals) and GCAPS were compared against the final diagnosis of GCA as determined by a GCA expert; CDUS was also compared with TAB results.

Results

Data from 198 patients were included: 60 patients with GCA and 138 patients without GCA. Sixty-two patients had a TAB. Using the final diagnosis by a GCA expert as a reference, the sensitivity, specificity, positive predictive value and negative predictive value were 93.3%, 98.5%, 96.6% and 97.1% for CDUS and 69.2%, 100%, 100% and 81.8% for TAB, respectively. The false-negative rate was 6.7% for CDUS and 30.8% for TAB. False-negative TAB mostly occurred when performed in referring hospitals (57.1%) as opposed to our vasculitis centre (21.1%). With a cut-off at 9.5 points, sensitivity for GCAPS was 98.3% and specificity 74.3%.

Conclusion

CDUS of the temporal and axillary arteries showed a high sensitivity and specificity and helped to diagnose GCA in patients with negative TAB. We validated that GCAPS is a useful clinical tool, with a score of <9.5 making the diagnosis of GCA improbable.

Current advances in giant cell arteritis

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

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

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

Comparison of 18- and 22-MHz probes for the ultrasonographic diagnosis of giant cell arteritis

PURPOSE

Little is known about the diagnostic concordance of images provided by ultrasound probes with emitting frequencies below or above 20 MHz for the diagnosis of giant cell arteritis (GCA).

METHODS

We compared, using Cohen's kappa statistic, data obtained with an 18-MHz and a 22-MHz probe for the ultrasonographic evaluation of temporal arteries in 80 patients referred for suspected GCA.

RESULTS

The halo sign was found in 25% of cases with the 18-MHz probe and in 35% with the 22-MHz probe. The compression sign was positive in 42% of cases with the 18-MHz probe and 48% with the 22-MHz probe. GCA was finally diagnosed in 20 patients (25%). The kappa coefficient of agreement was 0.76 (P < .001) for the halo sign, and 0.75 (P < .001) for the compression sign.

CONCLUSIONS

Images obtained by 18 MHz and 22-MHz frequency probes showed a good level of agreement for the diagnosis of GCA, but the 22-MHz probe yielded a correct diagnosis of GCA in 3 of the 7 patients in whom examination with the 18-MHz probe was negative.

A Review on the Value of Imaging in Differentiating between Large Vessel Vasculitis and Atherosclerosis

Imaging is becoming increasingly important for the diagnosis of large vessel vasculitis (LVV). Atherosclerosis may be difficult to distinguish from LVV on imaging as both are inflammatory conditions of the arterial wall. Differentiating atherosclerosis from LVV is important to enable optimal diagnosis, risk assessment, and tailored treatment at a patient level. This paper reviews the current evidence of ultrasound (US), 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography (FDG-PET), computed tomography (CT), and magnetic resonance imaging (MRI) to distinguish LVV from atherosclerosis. In this review, we identified a total of eight studies comparing LVV patients to atherosclerosis patients using imaging—four US studies, two FDG-PET studies, and two CT studies. The included studies mostly applied different methodologies and outcome parameters to investigate vessel wall inflammation. This review reports the currently available evidence and provides recommendations on further methodological standardization methods and future directions for research.

Is the intima-media thickness of temporal and axillary arteries influenced by cardiovascular risk?

Objectives

To measure with US the intima-media thickness (IMT) of temporal (superficial, parietal and frontal branches) and axillary arteries in subjects without a diagnosis of GCA and/or PMR with different cardiovascular (CV) risk; and to assess the performance of previously proposed cut-off values for normal IMT.

Methods

Subjects ≥ 50 years without a diagnosis of GCA or PMR were included. Bilateral US of the temporal arteries, including the frontal and parietal branches, and axillary arteries was performed by two sonographers using a 10–22 MHz and 6–18 MHz probe. The following previously proposed cut-offs were considered: superficial temporal artery: 0.42 mm; frontal branch: 0.34 mm; parietal branch: 0.29 mm; axillary artery: 1.0 mm.

Results

A total of 808 arteries in 101 subjects were evaluated; of these, 31 (30.7%) were classified as very high CV risk, seven (6.9%) as high, 34 (33.7%) as moderate and 29 (28.7%) as low risk. Subjects with very high or high risk showed higher IMT than those with moderate or low risk in the superficial temporal arteries [0.23 (s.d. 0.07) vs 0.20 (s.d. 0.04), P &lt; 0.01] and in the axillary arteries [0.54 (s.d. 0.17) vs 0.48 (s.d. 0.10), P = 0.002]. The IMT was higher than the reference cut-off in 13/808 (1.6%) arteries, in ≥1 artery in 10/101 subjects (10.1%). Of these 10 subjects, 8 (80%) were classified as having very high or high risk.

Conclusion

Our results suggest that CV risk might influence the US-determined IMT of the temporal and axillary arteries in subjects without GCA. Therefore, in patients with suspected GCA, particular attention should be paid when measuring the IMT in those patients with very high/high CV risk.

A Case of Microscopic Polyangiitis Presenting as Cranial Giant Cell Arteritis

We present a case of a 63-year old man with microscopic polyangiitis (MPA) in which the initial clinical presentation resembled the cranial form of giant cell arteritis (GCA) (headache, jaw claudication, low grade fever and raised inflammation markers). Ultrasound of both superficial common temporal arteries revealed signs indicative of vessel wall inflammation. Based on clinical picture and compatible imaging findings, treatment with corticosteroids for GCA was started. After initial improvement and steroid tapering, lung infiltrations, mononeuritis of the right peroneal nerve and cutaneous necrosis appeared and p-Antineutrophil cytoplasmic antibodies (ANCA) turned out to be positive. Three intravenous cyclophosphamide pulses for MPA led in disease remission and maintenance treatment with azathioprine followed. Two years later, the patient has no symptoms and laboratory parameters are normal. This case highlights that MPA can affect temporal arteries and can masquerade as cranial GCA.

One Giant Step for Giant Cell Arteritis: Updates in Diagnosis and Treatment

Purpose of Review

Giant cell arteritis (GCA), a medium and large vessel vasculitis occurring in the aged, remains a formidable disease, capable of taking both vision and life, through a multitude of vascular complications. Our understanding of the spectrum of its manifestations has grown over the years, to include limb claudication, aortitis, and cardiac disease, in addition to the more classic visual complications resulting from of ischemia to branches of the external and internal carotid arteries. While a clinical presentation of headache, jaw claudication, scalp tenderness, fever and other systemic symptoms and serum markers are together highly suggestive of the disease, diagnosis can be challenging in those cases in which classic symptoms are lacking. The purpose of this review is to update the reader on advances in the diagnosis and treatment of giant cell arteritis and to review our evolving understanding of the immunological mechanism underlying the disease, which have helped guide our search for novel therapies.

Recent Findings

There is increasing evidence supporting the use of Doppler ultrasound, dedicated post-contrast T1-weighted spin echo MRI of the scalp arteries and PET scan, which can together improve our diagnostic accuracy in cases in which temporal artery biopsy is either inconclusive or not feasible. Advances in our understanding of the immunological cascades underlying the disease have helped guide our search for steroid-sparing treatments for the GCA, the most important of which has been the IL-6 receptor antibody inhibitor tocilizumab, which has been shown to reduce cumulative steroid dose in a large multicenter, placebo-controlled prospective study. Other biologic agents, such as abatacept and ustekinumab have shown promise in smaller studies.

Summary

GCA is no longer a disease whose diagnosis is based exclusively on temporal artery biopsy and whose complications are prevented solely with the use of corticosteroids. Modern vascular imaging techniques and targeted immunologic therapies are heralding a new era for the disease, in which practitioners will hopefully be able to diagnosis it with greater accuracy and treat it with less ischemic complications and iatrogenic side effects.

Beyond Giant Cell Arteritis and Takayasu's Arteritis: Secondary Large Vessel Vasculitis and Vasculitis Mimickers

PURPOSE OF REVIEW

To provide an overview of mimickers of large vessel vasculitis (LVV), by the main presenting manifestation, i.e., systemic, vascular, and cranial manifestations.

RECENT FINDINGS

The main differential diagnoses in patients with giant cell arteritis (GCA) and Takayasu arteritis (TAK) presenting with systemic manifestations (i.e., fever, anorexia, weight loss, night sweats, arthralgia/myalgia, and/or increased inflammatory indexes) are neoplastic, infectious, or other inflammatory conditions. In patients with vascular manifestations (such as peripheral ischemia, vascular stenoses, or aneurysms), atherosclerosis and non-inflammatory vascular diseases should be excluded. In those presenting with predominant cranial symptoms (i.e., temporal headache, jaw claudication, scalp tenderness, transient or permanent vision loss), other causes of headache, cerebrovascular accidents, optic neuropathy, and neuromuscular syndromes need to be considered. The diagnosis of LVV maybe challenging, especially when patients present with atypical or incomplete clinical forms. In these cases, a multidisciplinary approach is strongly recommended.

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

Purpose of Review

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

Recent Findings

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

Summary

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