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

Imaging in vasculitis

PURPOSE OF REVIEW

Systemic vasculitides are characterized by inflammation of blood vessels. Their classification is based on the size of the blood vessels involved - large, medium, or small. Vasculitis early diagnosis and reliable monitoring are crucial to establish a treatment plan and prevent serious complications. Based on these considerations and depending on the location of the affected vessels, the importance of imaging modalities including ultrasonography (US), magnetic resonance Imaging (MRI), magnetic resonance angiography (MRA), computed tomography (CT), computed tomography angiography (CTA), and [18F]-fluoro-2-deoxy- d -glucose positron emission tomography/computed tomography (FDG-PET/CT) has progressively increased. In addition to physical exam and laboratory data, these imaging tools offer complementary information about vascular changes occurring in vasculitis.This review summarizes the different imaging modalities being utilized to diagnose and monitor vasculitis.

RECENT FINDINGS

The most recent update for the use of imaging in vasculitis is referenced in the 2023 European Alliance of Associations for Rheumatology (EULAR) recommendations and the American College of Rheumatology (ACR) guidelines in 2021. Recent advances in PET imaging in large vessel vasculitis include improved technological imaging acquisition and the use of novel radiotracers for cellular and immune targets. FDG-PET has now been demonstrated to have high sensitivity and specificity to detect temporal arteritis.

SUMMARY

Imaging plays a significant role in the evaluation of vasculitis and continues to gain importance in the diagnosis and monitoring of disease activity. Differences exist between the ACR guidelines, which advocates for temporal artery biopsy, and the EULAR guidelines, which favors imaging modalities for the initial evaluation and diagnosis of large vessel vasculitis (LVV). Prerequisites for appropriate clinical management utilizing imaging in patients with vasculitis are the availability and access to skilled clinicians to interpret the images and the cost of these techniques not being prohibitive.

Current and Emerging Approaches to Imaging Large Vessel Vasculitis

Large vessel vasculitides (LVV) comprise a group of inflammatory disorders that involve the large arteries, such as the aorta and its primary branches. The cause of LVV is often rheumatologic and includes giant cell arteritis and Takayasu arteritis. Giant cell arteritis is the most common form of LVV affecting people >50 years of age with a slight female predominance. Takayasu arteritis is more frequently seen in younger populations and is significantly more common in women. Prompt identification of LVV is crucial as it can lead to debilitating complications if left untreated, including blindness in the case of giant cell arteritis and large artery stenosis and aneurysms in the case of all forms of LVV. Noninvasive imaging methods have greatly changed the approach to managing LVV. Today, imaging (with ultrasound, magnetic resonance imaging, computed tomography, and positron emission tomography) is routinely used in the diagnosis of LVV. In patients with giant cell arteritis, imaging often spares the use of invasive procedures such as temporal artery biopsy. In addition, vascular imaging is also crucial for longitudinal surveillance of arterial damage. Finally, imaging is currently being studied for its role in assessing treatment response and ongoing disease activity and its potential value in determining the presence of vascular wall remodeling (eg, scarring). This review explores the current uses of noninvasive vascular imaging in LVV.

Clinical features, imaging use, and management in giant cell arteritis: a retrospective single-center study

This study examines the characteristics of patients with giant cell arteritis (GCA), the utilization of imaging in GCA diagnosis, and variations in GCA management among specialties. Subjects were identified from the Dallas VAMC database spanning 2010 to 2021 using ICD-9/10 codes for GCA and polymyalgia rheumatica, and a list of temporal artery biopsies (TAB). Patients lacking sufficient data to meet the ACR 1990 classification criteria for GCA were excluded. Categorical variables were compared using Fisher's exact test. Continuous variables were analyzed with the Kruskal-Wallis test. Among 209 identified patients, 41 were excluded due to insufficient data for ACR classification. The cohort comprised 91.9% males with a median age of 69. Of the remaining 168 patients, 42 received a final diagnosis of GCA, and 15 of these were confirmed with a positive TAB. The most reported initial symptoms were visual disturbances (75.5%) and headaches (67.7%). Ophthalmology was the initial physician for 46% of patients. GCA correlated with co-existing autoimmune diseases, glucocorticoid-sparing treatments, and consultation with a rheumatologist (p < 0.05). There were no significant differences in clinical features or management of the positive and negative TAB GCA groups. GCA presents with heterogeneous symptoms making diagnosis challenging. Scalp tenderness and headaches were significantly higher in GCA patients, but sub-group analysis revealed no significant differences among GCA patients. Vascular assessments and adjunct imaging modalities are underutilized. The establishment of multidisciplinary or fast-track clinics may enhance the optimization of GCA management. Key Points • The most common presenting symptoms were blurry vision/visual loss (75.5%), headache (67.7%), and scalp tenderness (35.9%) in descending order. • In sub-group analysis, no significant differences were found between GCA sub-groups, but when compared to the non-GCA group, were found to have significantly higher rates of headache and scalp tenderness. • Compared to other specialties, rheumatologists were more likely to use advanced imaging, and to prescribe glucocorticoid-sparing treatments. • Systematic and comprehensive assessment and multidisciplinary approach could improve diagnosis and management.

Hybrid PET/MRI of large vessel vasculitis : Radiation dose compared to PET/CT with view on cumulative effective dose

BACKGROUND

The diagnosis of large vessel vasculitis (LVV) is often challenging due to the various clinical appearances and the low prevalence. Hybrid imaging by positron emission tomography and computed tomography (PET/CT) is a highly relevant imaging modality for diagnostics and disease surveillance but may be associated with a significant amount of radiation dose especially in patients with complications.

OBJECTIVE

The aim of this retrospective analysis was to compare the image quality and impact of hybrid imaging methods PET/CT and PET/MRI on the potential for dose reduction.

METHODS

This retrospective single-center study included a cohort of 32 patients who were referred to PET/MRI for the evaluation of LVV, including graft infections and fever of unknown origin. This cohort was compared to a similar cohort of 37 patients who were examined with PET/CT in the same period. Mean radiation dose as well as image quality to establish a diagnosis were compared between the groups.

RESULTS

The mean radiation dose applied in PET/MRI was significantly lower when compared to PET/CT (mean 6.6 mSV vs. 31.7 mSV; p < 0.001). This effect was based on the partially multiphasic CT protocols. At the same time, diagnostic image quality using a 4-point scale showed similar results for both imaging modalities in the work-up of LVV.

CONCLUSION

With PET/MRI, the radiation exposure can be significantly reduced with similar image quality and diagnostic impact. Patients with LVV have a higher risk of receiving a clinically relevant cumulative effective dose (CED) and PET/MRI should be made available to them.

Imaging in Large Vessel Vasculitis-A Narrative Review

Vasculitis refers to a group of rare conditions characterized by the inflammation of blood vessels, affecting multiple systems. It presents a diagnostic and therapeutic challenge due to its broad clinical manifestations. Vasculitis is classified based on the size of the affected vessels: small, medium, large, or variable-sized. Large vessel vasculitis (LVV), particularly giant cell arteritis (GCA) and Takayasu arteritis (TAK), has garnered attention due to its significant morbidity and mortality. Both conditions involve immune-mediated inflammation of the vascular wall, despite differing in epidemiology and presentation. Early identification is crucial to prevent complications like organ ischemia and hemorrhage. Diagnostic accuracy can be hampered by false negative results, making comprehensive investigation essential. Vascular imaging, including computed tomography angiography (CTA), ultrasound (US), magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET-CT), is key in diagnosing vasculitis, revealing vessel wall thickening and other suggestive features. This article reviews typical and atypical CT and CTA findings in LVV, discusses imaging modalities, and highlights their role in therapeutic management and prognosis. It emphasizes the importance of a multidisciplinary approach and the critical role of radiologists in improving patient outcomes in LVV.

Comparison and Significance of Contrast-Enhanced Computed Tomographic Findings of Large-Vessel Vasculitis Before and After Treatment: Differences Between Takayasu Arteritis and Giant Cell Arteritis

Objective

Imaging is essential for diagnosing large-vessel vasculitis (LVV). During diagnostic imaging, assessing disease activity and vascular damage separately is important. Acute-phase findings represent disease activity, while chronic-phase findings represent vascular damage; however, whether the imaging findings are acute or chronic may be unclear. We investigated how vascular lesions change before and after treatment and whether they were acute- or chronic-phase findings.

Methods

Fifty-one patients with LVV who had undergone contrast-enhanced computed tomography (CT) scans from the neck to the pelvis before treatment and 1-4 months after treatment were recruited. Wall thickening, wall contrast enhancement, stenosis, occlusion, dilation, aneurysm, and calcification were semi-quantitatively assessed in 21 vessels from the common carotid to the common iliac artery.

Results

Twenty-four patients were diagnosed with Takayasu arteritis (TAK), and 27 with giant cell arteritis (GCA). Wall thickening and wall contrast enhancement improved after the treatment, which was especially significant in the GCA group. No significant differences in stenosis, occlusion, dilation, aneurysm, or calcification were observed before and after treatment. Stenosis and occlusion were more common with TAK, while calcification was more common with GCA.

Conclusion

Wall thickening and wall contrast enhancement are acute-phase findings (activity), while stenosis, occlusion, dilation, aneurysm, and calcification are chronic-phase findings (damage). The frequencies of these findings differ between TAK and GCA.

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.

Transorbital ultrasound in the diagnosis of giant cell arteritis

OBJECTIVES

The objective of this study was to prospectively evaluate the diagnostic efficacy of transorbital ultrasound (TOS) in patients newly diagnosed with giant cell arteritis (GCA), presenting with visual symptoms.

METHODS

Patients with newly diagnosed, untreated GCA were examined using TOS, assessing central retinal artery flow velocity [peak systolic velocity (PSV), end-diastolic velocity (EDV), resistance index (RI)], and optic nerve diameter (OND). Vascular ultrasound was conducted to evaluate the superficial temporal arteries, their branches, facial, axillary, carotid, and vertebral arteries.

RESULTS

We enrolled 54 GCA patients, 27 with visual symptoms, and 27 healthy controls. Eyes of GCA patients with visual symptoms demonstrated significantly lower PSV and EDV (PSV: β = -1.91; P = 0.029; EDV: β = -0.57; P = 0.032) and significantly elevated OND (β = 0.79; P = 0.003) compared with controls. RI did not significantly differ from controls (β = -0.06, P = 0.129). Vascular ultrasound identified an average of 8.7 (SD ± 2.8) pathological vessels per GCA patient. A significant negative association was observed between the number of affected vessels and both PSV (P = 0.048) and EDV (P = 0.040). No association was found with RI (P = 0.249), while a positive significant association was noted with OND (P < 0.001).

CONCLUSIONS

This study pioneers the application of TOS to assess structural eye changes in newly diagnosed, untreated GCA patients with visual symptoms. Our findings suggest reduced central retinal artery flow and increased optic nerve diameter as potential biomarkers for serious ocular involvement in GCA. The detected association between internal and external carotid artery involvement indicates a common pathophysiological mechanism underlying systemic and ocular manifestations of GCA.

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.

Molecular imaging of large vessel vasculitis

Large vessel vasculitis (LVV) affects mainly large arteries with giant cell arteritis (GCA) and Takayasu arteritis (TAK) being the two most frequent forms. Clinical symptoms can be non-specific, including headache, fatigue, weight loss, and change in vision. Untreated, LVV may also lead to serious complications such as blindness, aortic aneurysm and dissection. Therefore, rapid recognition of the disease leading to accurate diagnosis and appropriate treatment is essential. FDG-PET/CT imaging has emerged as a sensitive marker of active vascular inflammation and its use in the management of LVV is now integrated in guidelines. In this article, we will discuss the role of FDG-PET/CT for the diagnosis of LVV and monitoring of therapy, as well as review technical and interpretation parameters.

Diffusion-weighted magnetic resonance imaging for the diagnosis of giant cell arteritis: a comparison with T1-weighted black-blood imaging

OBJECTIVES

To investigate the diagnostic performance of diffusion-weighted imaging (DWI) of the superficial cranial arteries in the diagnosis of GCA.

METHODS

Retrospectively, 156 patients with clinically suspected GCA were included. A new 4-point ordinal DWI rating scale was developed. A post-contrast, fat-suppressed, T1-weighted 'black-blood' sequence (T1-BB) was rated for comparison. Ten arterial segments were assessed: common superficial temporal arteries, temporal and parietal branches, occipital and posterior auricular arteries bilaterally. The expert clinical diagnosis after ≥6 months of follow-up was the diagnostic reference standard. Diagnostic accuracy was evaluated for different rating methods.

RESULTS

The study cohort consisted of 87 patients with and 69 without GCA. For DWI, the area under the curve was 0.90. For a cut-off of ≥2 consecutive pathological slices, DWI showed a sensitivity of 75.9%, a specificity of 94.2% and a positive likelihood ratio of 13.09. With a cut-off of ≥3 consecutive pathological slices, sensitivity was 70.1%, specificity was 98.6% and the positive likelihood ratio was 48.38. For the T1-BB, values were 88.5%, 88.4% and 7.63, respectively. The inter-rater analysis for DWI with a cut-off of ≥2 pathological slices showed a kappa of 1.00 on the patient level and 0.85 on the arterial segment level. For the T1-BB the kappa was 0.78 and 0.79, respectively.

CONCLUSION

DWI of the superficial cranial arteries demonstrates a good diagnostic accuracy and reliability for the diagnosis of GCA. DWI is widely available and can be used immediately in clinical practice for patients with suspected GCA.

Primary Large Vessel Vasculitis: Takayasu Arteritis and Giant Cell Arteritis

Takayasu arteritis (TA) and Giant cell arteritis (GCA) are large vessel vasculitides, with TA targeting the aorta and its branches, and GCA targeting both large and medium-sized arteries. Early diagnosis of TA and GCA are of great importance, since delayed, inappropriate or no treatment can result in severe and permanent complications. Imaging plays a central role in establishing diagnosis, targeting lesions for confirmational diagnostic biopsy, specifically for GCA, and longitudinal disease evolution. In this article, we discuss imaging diagnosis of large artery vasculitis and the value of different imaging modalities.

[Diagnostics and treatment of large vessel vasculitis]

BACKGROUND

Giant cell arteritis (GCA) and Takayasu arteritis (TAK), as the main representatives of large vessel vasculitis, are rheumatological autoimmune disorders associated with inflammatory vessel wall changes in the arterial system that can lead to many types of organ damage.

MATERIAL AND METHODS

In this review the current scientific evidence on the diagnostics and treatment of large vessel vasculitis is evaluated and discussed.

RESULTS

In addition to the medical history and clinical presentation, imaging techniques nowadays represent the core of large vessel vasculitis diagnostics and have largely replaced the histological confirmation of GCA. After the diagnosis, acute treatment with glucocorticoids should be initiated as rapidly as possible but in the long term this should be tapered out or replaced by a steroid-sparing basic treatment. In contrast to GCA with already available options and other biologic disease-modifying antirheumatic drugs (DMARDs) about to be approved, there are still no approved biologic DMARD treatment options available for the less common TAK.

CONCLUSION

In contrast to the substantial progress in imaging diagnostics of large vessel vasculitis and with respect to the treatment of GCA, the much rarer TAK still requires intensive research efforts, especially to improve the treatment situation.

PET vascular activity score for predicting new angiographic lesions in patients with Takayasu arteritis: a Chinese cohort study

OBJECTIVE

To investigate the ability of 18F-fluorodeoxyglucose PET/CT to predict new lesions in Takayasu arteritis.

METHODS

Eighty-two Chinese patients with newly diagnosed Takayasu arteritis were recruited. Their clinical characteristics, serum biomarkers and imaging results were recorded at baseline and every visit. They were followed up for at least 2 years. New angiographic lesions were evaluated by magnetic resonance angiography. Baseline PET vascular activity scores (PETVAS) for predicting new lesions were evaluated.

RESULTS

At baseline, a moderate correlation was observed between PETVAS and ESR (r = 0.74, P < 0.01) and CRP level (r = 0.69, P < 0.01). Overall, 18 (22%) patients showed new lesions on imaging during a median follow-up time of 36 months. The median time to the first occurrence of new lesions was 18 months. Compared with patients without new lesions, the patients with new lesions included more female patients (67.2% vs 94.4%, P = 0.03), patients with higher ESR values (20 vs 49, P = 0.02) and patients with active disease (62.5% vs 94.4%, P < 0.01). Multivariate Cox regression analysis revealed PETVAS was an independent risk factor for new angiographic lesions (PETVAS ≥8, hazard ratio = 7.56; 95% CI 2.20, 26.01, P < 0.01) with adjustment of age, sex, chest pain, ESR and Physician Global Assessment. Furthermore, patients with PETVAS ≥8 at baseline were more likely to experience adverse events including arterial ischaemic events during the follow-up.

CONCLUSION

PETVAS showed good performance in predicting new lesions in Takayasu arteritis.

The role of 18F-fluorodeoxyglucose PET/computed tomography in the diagnosis and monitoring of large vessel vasculitides - a review article

In the last two decades, advancements in positron emission tomography (PET) technology have increased the diagnostic accuracy of patients with large-vessel vasculitis (LVV). Numerous systematic reviews and meta-analyses have been conducted, and patients suspected of having LVV can be diagnosed earlier with 18F-FDG PET. Two subtypes, giant cell arteritis (GCA) and Takayasu arteritis (TA), will progress when their response to corticosteroids and enhanced immunosuppression is inadequate. In the majority of patients, disease activity cannot be monitored solely through laboratory procedures; consequently, glucose metabolism may be a source of potential biomarkers. In this article, we discuss the current state of 18F-FDG PET/CT imaging standards.

Takayasu Arteritis: A Difficult Diagnosis in a Patient With an Extensive Cardiovascular History

Large vessel vasculitides, such as Takayasu arteritis (TAK), are rare inflammatory conditions primarily affecting the aorta and its major branches. Its nonspecific symptoms and potential resemblance to atherosclerotic disease often pose diagnostic challenges. We present a case of a 57-year-old male with a history of extensive cardiovascular disease, initially attributed to atherosclerosis, resulting in several interventions, such as catheterization and major cardiac surgery, which didn't help improve his symptoms. Further evaluation revealed diffuse wall thickening of the aorta and its roots, as well as labs that suggested elevated inflammatory markers, comprehensive review of his chart and previous admissions, revealed that he had a well-documented aortitis for which he underwent a biopsy, which at the time was unrevealing. Furthermore, as he had significant aortic aneurysmal dilation, a thoracic cardiovascular surgeon remitted him to the rheumatology clinic, where he was placed on a prednisone taper and methotrexate regimen. Unfortunately, he redeveloped symptoms, and plans were made to transition to a tumor necrosis alpha (TNF-alpha) inhibitor. Our case highlights the importance of an accurate diagnosis and the prompt initiation of appropriate treatment in challenging cases of large vessel vasculitides. This case also underscores the need for heightened clinical awareness and interdisciplinary collaboration to ensure optimal patient care.

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.

Takayasu arteritis in peripartum period-A clinical paradox

Takayasu arteritis is a primary systemic vasculitides occurring among women in the childbearing age group. This interaction between TA and pregnancy is an area of interest that has to be addressed. Preconception and antepartum management of arterial hypertension and TAK disease activity is important to improve maternal and fetal outcomes.

Positron Emission Tomography Imaging in Vasculitis

Systemic vasculitides comprise a group of autoimmune diseases affecting blood vessels. [18F]-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (FDG-PET/CT) plays an important role in the diagnosis and therapeutic monitoring of vasculitides affecting large-sized and medium-sized vessels. FDG-PET/CT also provides complementary information to other vascular imaging tools. The resolution and sensitivity of newer generation scanners continues to increase, hereby improving the ability of FDG-PET/CT to accurately assess the full disease extent in patients with vasculitis. Novel tracers targeting specific immune cells will allow for more detailed detection of vascular infiltrates.

Temporal artery biopsy: time for a rethink on training?

BACKGROUND

Temporal artery biopsy (TAB) is often performed by ophthalmology trainees without direct supervision. The traditional model of 'see one, do one, teach one' still prevails in most units. Whilst it is generally a safe procedure, damage to the temporal branch of the facial nerve has been reported when harvesting the frontal branch of the superficial temporal artery.

METHODS

A survey of trainees from Wessex, Wales, London and Severn deaneries was performed to look at current training techniques, anatomical knowledge and practice.

RESULTS

38 trainees responded to the survey, with complete responses from 28 participants. Formal teaching of the anatomical considerations in TAB was not reported by any trainee, with informal teaching being standard practice. Whilst 61% of respondents reported having learnt about the anatomical 'danger zone' for facial nerve damage, 97% of trainees chose an incision that fell within this zone when given a choice between potential incision sites.

CONCLUSION

TAB remains a largely trainee-taught, trainee-performed procedure. Most trainees are not aware of how to avoid the risk of damage to the temporal branch of the facial nerve. We suggest harvesting the parietal branch of the temporal artery via an incision outside the anatomical 'danger zone'. In our experience, this is an easily taught technique that minimises the potential risk of damage to the frontal branch of the facial nerve.

Differentiation of lower limb vasculitis from physiological uptake on FDG PET/CT imaging

PURPOSES

To analyze the difference of 2-deoxy-2-[¹⁸F]fluoro-D-glucose (¹⁸F-FDG) uptake between vasculitis and non-vasculitic patients in PET/CT imaging and the factors related to vascular uptake in non-vasculitic patients. To investigate the feasibility of identifying vasculitis of the lower limb and physiological uptake with delayed imaging.

PROCEDURES

Among 244 patients who underwent PET/CT examination, imaging features of patients with or without vasculitis were retrospectively analyzed. The factors related to FDG uptake in the lower limb vessels of non-vasculitic patients were analyzed. Another 44 patients with suspected systemic vasculitis in PET/CT were prospectively studied to analyze the efficacy of delayed imaging on differentiating vascular uptake in lower limbs.

RESULTS

In PET/CT imaging of patients with vasculitis, involvement of trunk vessels showed segmental or diffuse FDG distribution. Lower limb vascular involvement showed reticular uptake accompanied by nodular or patchy changes. In non-vasculitic patients, vascular uptake mainly showed linear uptake in lower limb vessels and there was no significant difference in uptake degree compared with vasculitis patients. Body weight and interval time were the independent influence factors of vascular uptake in lower limbs of non-vasculitic patients. In delayed imaging, lower limb vasculitis all showed reticular uptake and physiological uptake all showed a linear pattern. ROC analysis showed the change rate of SUV_max (≥ 20%) between early and delayed imaging could delineate physiological vascular uptake with a sensitivity of 100% and specificity of 81.0%.

CONCLUSIONS

When PET/CT is used for the diagnosis and classification of vasculitis, the physiological uptake of lower limb vessels may mislead the diagnosis. PET/CT imaging features or delayed imaging improved diagnostic efficacy.

A role of FDG PET/CT for Response Assessment in Large Vessel Disease?

Currently, a large amount of evidence-based data clearly demonstrates the usefulness of [¹⁸F]FDG PET/CT in the diagnosis of several infectious and inflammatory diseases, including those related to the large vessels. The aim of this article is to clarify whether, beyond initial diagnosis, [¹⁸F]FDG PET/CT may have a role in treatment response assessment in inflammatory or infectious diseases of the large vessels, including large vessel vasculitis, vascular graft infection, retroperitoneal fibrosis/chronic periaortitis and infective native aortic aneurysms. Rapidly accumulating data suggest that [¹⁸F]FDG PET/CT could be a valuable imaging method for therapy monitoring in some infectious and inflammatory diseases of large vessels. The available data, albeit preliminary, indicate that [¹⁸F]FDG PET/CT could even play a pivotal role in the management of these diseases, leading to better drug dosage, confirmation of the usefulness of the treatment, and early modification of the therapeutic strategy. However, to date, the role of [¹⁸F]FDG PET/CT for treatment assessment in large vessel diseases, in particular large vessel vasculitis, is not clearly defined and well-designed prospective studies are needed to confirm its possible role in treatment monitoring and treatment guidance.

Giant Cell Arteritis: A Case-Based Narrative Review of the Literature

Purpose of Review

Giant cell arteritis (GCA) is a chronic, inflammatory condition, primarily affecting the medium and larger arteries. The purpose of this narrative review is to describe GCA in the context of headache and facial pain, based on a case and the available current literature. Understanding the etiology, pathophysiology, the associated conditions, and the differential diagnoses is important in managing GCA.

Recent Findings

In a patient presenting with unilateral facial/head pain with disturbances of vision, GCA should be considered in the differential diagnosis. There is an association of GCA with several comorbid conditions, and infections including coronavirus-19 (COVID-19) infection. Management of GCA primarily depends upon the identification of the affected artery and prompt treatment. Permanent visual loss and other serious complications are associated with GCA.

Summary

GCA is characterized by robust inflammation of large- and medium-sized arteries and marked elevation of systemic mediators of inflammation. An interdisciplinary approach of management involving the pertinent specialties is strongly recommended.

Affected Microcirculation and Vascular Hemodynamics in Takayasu Arteritis

Introduction: Takayasu arteritis (TAK) is a rare inflammatory disease affecting aorta and its major branches. Ultrasound (US) can detect inflammatory features in the arterial wall, but less is known regarding skin microcirculation and vascular hemodynamics. The aim was to study if assessment of these variables could add valuable information regarding vascular affection in TAK.

Methods: 17 patients diagnosed with TAK and 17 age- and sex-matched healthy controls were included. Microcirculatory peak oxygen saturation (OxyP) in the skin after induced ischemia was evaluated with laser Doppler flowmetry/diffuse reflectance spectroscopy. Cerebrovascular reserve capacity (CVR) in the brain was assessed with transcranial Doppler (TCD). Pulse waves were recorded in the radial artery by the aid of applanation tonometry, for calculation of central augmentation index (AIx75). Intima-media thickness (IMT) and stenosis/occlusions were evaluated using US in carotid and central arteries.

Results: Reduced OxyP (79 ± 8% vs. 87 ± 4%, p &lt; 0.001) was seen in patients with TAK regardless of significant arterial stenosis/occlusion or not. Increased AIx75 (22.3 ± 13.6 vs. 9.2 ± 16.3, p = 0.01) was seen in TAK patients without significant stenosis/occlusions. No differences were found in CVR, regardless of proximal stenosis. However, signs of a more high-resistance flow profile were seen in arteria cerebri media.

Conclusion: Regardless of arterial stenosis or not, impaired microcirculation of the skin and preserved CVR in the brain were found in subjects with TAK. Signs of increased arterial stiffness in the brain and central arteries were observed. The value of these findings for prediction of future cardiovascular events needs to be clarified in further studies.

Carotid intima-media thickness/diameter ratio and peak systolic velocity as risk factors for neurological severe ischemic events in Takayasu's arteritis

Objective

To characterize Takayasu arteritis (TAK) with supra-aortic involvement and determine the associations between clinical features, carotid ultrasonographic (US) parameters, and neurological severe ischemic events (SIE).

Methods

Patients with supra-aortic involvement including brachiocephalic trunk, bilateral common carotid artery and internal carotid artery, and bilateral subclavian and vertebral artery and baseline carotid US examination were enrolled from the East China Takayasu arteritis cohort. Bilateral carotid diameter, intima-media thickness (IMT), and peak systolic velocity (PSV) were measured by US. Then, IMT/diameter ratio (IDR) was calculated. Risk factors associated with neurological SIE were analyzed by multivariate logistic regression.

Results

Totally, 295 patients were included, of whom 260 (88.14%) were female, and 93 (31.53%) experienced neurological SIE. Involved supra-aortic artery distribution (p=0.04) and number (p<0.01) differed between neurologic and non-neurologic SIE subjects, showing higher prevalence of common carotid and vertebral artery involvement after Bonferroni correction and 56.99% patients having more than four involved arteries in neurological SIE group. The bilateral IDR (p<0.01) differed between patients with and without neurological SIE. The carotid IDR (left: cut-off value ≥0.55, odds ratio [OR] 2.75, 95% confidence interval [CI] 1.24-6.07, p=0.01; right: ≥0.58, OR 2.70, 95% CI 1.21-6.02, p=0.01) and left carotid PSV (≤76.00 cm/s, OR 3.09; 95% CI 1.53-6.27; p<0.01) as well as involved supra-aortic artery number (≥4, OR 2.33, 95% CI 1.15-4.72, p =0.02) were independently associated with neurological SIE.

Conclusion

The carotid IDR and PSV might be performed as valuable markers for recognizing neurological SIE in TAK patients with supra-aortic lesions.

Vertebral and carotid artery aneurysms and polyarthritis in a patient with Takayasu arteritis: A case report

Takayasu arteritis (TA) is a common autoimmune disease in the clinical setting. However, vertebral artery aneurysms caused by TA are rarely reported. We herein describe a 28-year-old man with multiple vertebral artery aneurysms and carotid artery aneurysms caused by TA, which showed typical wall thickening and lumen dilation with a "string of beads" appearance by Doppler ultrasound and radiology. Previous studies have shown that most TA-associated vertebral artery lesions are stenosis, occlusion, and dissection of the intracranial part of the artery. In this case, TA mainly affected the cervical segment of the vertebral artery (the intracranial segment was not obviously involved), and the main manifestations were aneurysms and occlusion. This case provides more information for further understanding of TA-associated vertebral artery lesions.

PET-Based Imaging with 18F-FDG and 18F-NaF to Assess Inflammation and Microcalcification in Atherosclerosis and Other Vascular and Thrombotic Disorders

Positron emission tomography (PET) imaging with ¹⁸F-fluorodeoxyglucose (FDG) represents a method of detecting and characterizing arterial wall inflammation, with potential applications in the early assessment of vascular disorders such as atherosclerosis. By portraying early-stage molecular changes, FDG-PET findings have previously been shown to correlate with atherosclerosis progression. In addition, recent studies have suggested that microcalcification revealed by ¹⁸F-sodium fluoride (NaF) may be more sensitive at detecting atherogenic changes compared to FDG-PET. In this review, we summarize the roles of FDG and NaF in the assessment of atherosclerosis and discuss the role of global assessment in quantification of the vascular disease burden. Furthermore, we will review the emerging applications of FDG-PET in various vascular disorders, including pulmonary embolism, as well as inflammatory and infectious vascular diseases.

Atypical Posterior Reversible Encephalopathy Syndrome (PRES) in a Patient with Polymyalgia Rheumatica and Giant Cell Arteritis

Posterior reversible encephalopathy syndrome (PRES) is a potentially life-threatening condition, composed of focal neurologic symptoms and peculiar magnetic resonance imaging (MRI) findings suggestive for cerebral vasogenic edema. PRES has been predominantly associated with severe hypertension, but a concomitant inflammatory state, common in vasculitis, can contribute to worsening cerebral vasogenic edema towards cytotoxic edema, and it should be promptly treated with glucocorticoids (GC). Atypical cases of PRES should be suspected in cases of focal neurologic symptoms, associated with severe hypertension, and systemic inflammation. We report the first description of a patient with polymyalgia rheumatica and giant cell arteritis who developed PRES after GC discontinuation for arthroscopic surgery.

Post-operative outcomes of inflammatory thoracic aortitis: a study of 41 patients from a cohort of 1119 surgical cases

Aortitis is found in 2-12% of thoracic aortic aneurysm repair/replacement surgeries. Yet little is known about such patients' post-operative outcomes or the role of post-operative corticosteroids. The study was undertaken across three tertiary referral hospitals in Sydney, Australia. Prospectively collected data for all thoracic aortic repair/replacement patients between 2004 and 2018 was accessed from a national surgical registry and analysed. Histopathology records identified cases of inflammatory aortitis which were subclassified as clinically isolated aortitis (CIA), giant cell arteritis (GCA), Takayasu (TAK) or other aortitis. Between-group outcomes were compared utilising logistic and median regression analyses. Between 2004 and 2018, a total of 1119 thoracic aortic surgeries were performed of which 41 (3.7%) were inflammatory aortitis cases (66% CIA, 27% GCA, 5% TAK, 2% other). Eight out of 41 (20%) aortitis patients received post-operative corticosteroids. Compared to non-aortitis patients, the aortitis group was predominantly female (53.7% vs. 28.1%, p < 0.01), was older (mean 70 vs. 62 years, p < 0.01) and had higher prevalence of hypertension (82.9% vs. 67.1%, p = 0.03) and pre-operative immunosuppression (9.8% vs. 1.4%, p < 0.01). There was no difference (p > 0.05) between aortitis and non-aortitis groups for 30-day mortality (7.3% vs 6.5%), significant morbidity (14.6% vs. 22.4%), or infection (9.8% vs. 6.4%). Outcomes were similar for the non-corticosteroid-treated aortitis subgroup. Histologic evidence of inflammatory thoracic aortitis following surgery did not affect post-operative mortality or morbidity. Withholding corticosteroids did not adversely affect patient outcomes. These findings will assist rheumatologists and surgeons in the post-operative management of aortitis.

Quantitative ultrasound to monitor the vascular response to tocilizumab in giant cell arteritis

OBJECTIVES

To characterize the effect of ultra-short glucocorticoids followed by Tocilizumab monotherapy on the intima-media thickness (IMT) in GCA.

METHODS

Eighteen GCA patients received 500 mg for 3 consecutive days (total of 1500mg) i.v. methylprednisolone on days 0-2, followed by i.v. Tocilizumab (8 mg/kg) on day 3 and thereafter weekly s.c. Tocilizumab injections (162 mg) over 52 weeks. US of temporal (TAs), axillary (AAs) and subclavian (SAs) arteries was performed at baseline, on days 2-3, and at weeks 4, 8, 12, 24 and 52. The largest IMT of all segments and IMT at landmarks of AA/SA were recorded. IMT was scaled by mean normal values and averaged. Each segment was classified according to diagnostic cut-offs.

RESULTS

Of the 18 GCA patients, 16 patients had TA and 6 had extracranial large artery involvement. The IMT showed a sharp decline on day 2/3 in the TAs and AAs/SAs. In TAs, this was followed by an increase to baseline levels at week 4 and a subsequent slow decrease, which was paralleled by decreasing symptoms and achievement of clinical remission. The AAs/SAs showed a new signal of vasculitis at week 4 in three patients, with an IMT increase up to week 8.

CONCLUSION

Glucocorticoid pulse therapy induced a transient decrease of the IMT in TAs and AAs/SAs. Tocilizumab monotherapy resulted in a slow and steady decrease in IMT of the TAs and a smaller and delayed effect on the AAs/SAs. The data strongly support a remission-inducing effect of Tocilizumab and argue the case for US having an important role in monitoring disease activity in GCA.

TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT03745586.

Giant cell arteritis: A case report and review of literature

Giant cell arteritis, the most common form of vasculitis in the elderly, is characterized by granulomatous inflammation of arteries, which can lead to serious, life-threatening conditions including aortic aneurysms, ruptures, and dissections as well as blindness. Since GCA can be treated by immunosuppressant therapy, such as corticosteroids, early diagnosis and treatment may reduce the risk of serious disability and morbidity. While temporal artery biopsy is considered the gold standard to diagnosis giant cell arteritis, it is intrusive with inherent risks as well as unreliable due to tissue sampling. Imaging studies, such as computerized tomography, are nonintrusive and have been shown to identify vasculitis including giant cell arteritis. We present a case of a 72-year-old male patient who was diagnosed with giant cell arteritis by temporal artery biopsy during surgery for aortic aneurysm and coronary artery bypass graft. Computerized tomography imaging studies, prior to the surgery and biopsy, were suggestive of vasculitis. This case serves to emphasize the beneficial role of imaging studies to assess vasculitis, including giant cell arteritis, that can be done prior to the progressive development of more serious debilitating and potentially fatal pathology.

Fecal S100A12 in Takayasu arteritis predicts disease activity and intestinal involvement

Gastrointestinal involvement in Takayasu Arteritis (TA) requires invasive or expensive diagnostic studies. Instead a fecal biomarker can be used as an initial screening test. In this context, S100A12 is promising as an established biomarker in intestinal inflammation and its role in TA pathogenesis. As such we aimed to test the feasibility of fecal S100A12 as a means of the fecal biomarker in gastrointestinal involvement in TA in this pilot study. Our study population consisted of 30 TA patients and 14 control patients with non-inflammatory arthralgia. Patients with inflammatory or infectious gastrointestinal tract diseases, or used oral antibiotics or NSAIDs for the 3 weeks were excluded. Vasculitis involvements were determined with cross-sectional radiologic studies. TA disease activity was evaluated per Indian Takayasu's Activity Score (2010) criteria and vascular involvements were classified according to Numano classification. ELISA test was used to determine fecal S100A12 levels. Fecal S100A12 levels were higher in TA patients when compared to the controls (37.9 ng/ml vs. 12.5 ng/ml p = 0.038). ESR and CRP levels were also higher in the TA group, however not correlated with fecal S100A12. Among TA patients, fecal S100A12 levels were higher inactive ones with ITAS2010 > 1 (72.9 ng/ml vs. 16.7 ng/ml p = 0.016) correlated with total ITAS2010 scores. (R = 0.52 p = 0.003). TA patients with abdominal symptoms had higher fecal S100A12 levels when compared to the remaining TA population (327.8 ng/ml vs. 28.0 ng/ml p = 0.003). However, fecal S100A12 levels in patients with or without mesenteric vessel involvement did not differ. Fecal S100A12 shows promise as a fecal biomarker to screen intestinal ischemia and inflammatory bowel disease in TA patients.

Role of temporal artery resection in Horton's arteritis (Review)

Horton's arteritis is found in the literature under various names, such as temporal arteritis, Horton's disease senile arteritis, granulomatous arteritis or giant cell arteritis (GCA). The pathogenic mechanism is the result of an inflammatory cascade triggered by a still unknown factor that causes dendritic cells in vessels to recruit T cells and macrophages, which form granulomatous infiltrates. The clinical picture consists of a daily headache with temporal localization, with moderate to severe intensity, unilateral or bilateral, with a history of months, years. Other changes may include pain in the cheek or tongue during chewing (claudication), weight loss, generalized fatigue, low-grade fever, and frequent pain in the limbs, in the context of coexisting rheumatic polymyalgia. Visual symptoms represent a special category, involving blurred vision, scotomas, and even sudden blindness. Histopathological examination of the temporal artery biopsy reveals focal thickening of the intima, with interruption of the lamina propria, with transmural inflammatory infiltrates, sometimes with multinucleated giant cells. In this article, we aim to review the role of temporal artery resection in the diagnosis of Horton's arteritis, but we also discuss the hypothesis of a potential therapeutic benefit of this procedure. However, there are also clinical situations in which there has been a considerable improvement in clinical symptoms and especially in vision deficit, with the improvement of the visual field after surgery performed for biopsy. It is difficult to estimate the influence of temporal artery resection alone, given that most patients also have concomitant cortisone treatment. However, in some cases, the rapid improvement of symptoms immediately after surgery, with the improvement of visual acuity and visual field, along with the disappearance of the headaches, can create the premises for future studies on a therapeutic contribution of temporal artery resection in GCA.

Imaging Tests in the Early Diagnosis of Giant Cell Arteritis

Early recognition of giant cell arteritis (GCA) is crucial to avoid the development of ischemic vascular complications, such as blindness. The classic approach to making the diagnosis of GCA is based on a positive temporal artery biopsy, which is among the criteria proposed by the American College of Rheumatology (ACR) in 1990 to classify a patient as having GCA. However, imaging techniques, particularly ultrasound (US) of the temporal arteries, are increasingly being considered as an alternative for the diagnosis of GCA. Recent recommendations from the European League Against Rheumatism (EULAR) for the use of imaging techniques for large vessel vasculitis (LVV) included US as the first imaging option for the diagnosis of GCA. Furthermore, although the ACR classification criteria are useful in identifying patients with the classic cranial pattern of GCA, they are often inadequate in identifying GCA patients who have the extracranial phenotype of LVV. In this sense, the advent of other imaging techniques, such as magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET)/CT, has made it possible to detect the presence of extracranial involvement of the LVV in patients with GCA presenting as refractory rheumatic polymyalgia without cranial ischemic manifestations. Imaging techniques have been the key elements in redefining the diagnostic work-up of GCA. US is currently considered the main imaging modality to improve the early diagnosis of GCA.

Application progress of multiple imaging modalities in Takayasu arteritis

Takayasu arteritis (TA) is a chronic, idiopathic, granulomatous large vessel vasculitis of unknown etiology. The clinical manifestations of TA are incredibly variable, mainly depending on the location of the lesions. In the light of its insidious progress and the diversity of clinical manifestations, a substantial proportion of patients might experience a considerable delay in diagnosis, which leads to irreversible malignant complications, highlighting the importance of early diagnosis. There has been accumulating evidence that early identification of disease is pivotal to initiate timely therapy and ameliorate the prognosis. Therefore, this review discusses and summarizes the latest evidence on the application progress of multiple imaging modalities.

Tocilizumab in refractory Caucasian Takayasu's arteritis: a multicenter study of 54 patients and literature review

Objective:

To assess the efficacy and safety of tocilizumab (TCZ) in Caucasian patients with refractory Takayasu’s arteritis (TAK) in clinical practice.

Methods:

A multicenter study of Caucasian patients with refractory TAK who received TCZ. The outcome variables were remission, glucocorticoid-sparing effect, improvement in imaging techniques, and adverse events. A comparative study between patients who received TCZ as monotherapy (TCZ_MONO) and combined with conventional disease modifying anti-rheumatic drugs (cDMARDs) (TCZ_COMBO) was performed.

Results:

The study comprised 54 patients (46 women/8 men) with a median [interquartile range (IQR)] age of 42.0 (32.5–50.5) years. TCZ was started after a median (IQR) of 12.0 (3.0–31.5) months since TAK diagnosis. Remission was achieved in 12/54 (22.2%), 19/49 (38.8%), 23/44 (52.3%), and 27/36 (75%) patients at 1, 3, 6, and 12 months, respectively. The prednisone dose was reduced from 30.0 mg/day (12.5–50.0) to 5.0 (0.0–5.6) mg/day at 12 months. An improvement in imaging findings was reported in 28 (73.7%) patients after a median (IQR) of 9.0 (6.0–14.0) months. Twenty-three (42.6%) patients were on TCZ_MONO and 31 (57.4%) on TCZ_COMBO: MTX (n = 28), cyclosporine A (n = 2), azathioprine (n = 1). Patients on TCZ_COMBO were younger [38.0 (27.0–46.0) versus 45.0 (38.0–57.0)] years; difference (diff) [95% confidence interval (CI) = -7.0 (-17.9, -0.56] with a trend to longer TAK duration [21.0 (6.0–38.0) versus 6.0 (1.0–23.0)] months; diff 95% CI = 15 (-8.9, 35.5), and higher c-reactive protein [2.4 (0.7–5.6) versus 1.3 (0.3–3.3)] mg/dl; diff 95% CI = 1.1 (-0.26, 2.99). Despite these differences, similar outcomes were observed in both groups (log rank p = 0.862). Relevant adverse events were reported in six (11.1%) patients, but only three developed severe events that required TCZ withdrawal.

Conclusion:

TCZ in monotherapy, or combined with cDMARDs, is effective and safe in patients with refractory TAK of Caucasian origin.

Development and Proof of Concept of a Low-Cost Ultrasound Training Model for Diagnosis of Giant Cell Arteritis Using 3D Printing

Objectives: Currently, ultrasound (US) is widely used for the diagnosis of giant cell arteritis (GCA). Our aim was to develop a low-cost US training model for diagnosis of GCA of the temporal and axillary artery using a modern 3D printing system. Methods: We designed an US training model, which enables measurement of the intima-media thickness (IMT) of temporal and axillary arteries using Autodesk Fusion360. This model was printed using a modern 3D printer (Formlabs Form3) and embedded in ballistic gelatine. The ultrasound images including measurement of the IMT by ultrasound specialists in GCA were compared to ultrasound images in acute GCA and healthy subjects. Results: Our ultrasound training model of the axillary and temporal artery displayed a very similar ultrasound morphology compared to real US images and fulfilled the OMERACT ultrasound definitions of normal and pathological temporal and axillary arteries in GCA. The IMT measurements were in line with published cut-off values for normal and pathological IMT values in GCA and healthy individuals. When testing the models on blinded US specialists in GCA, they were identified correctly in all test rounds with an intra-class coefficient of 0.99. Conclusion: The production of low-cost ultrasound training models of normal and pathological temporal and axillary arteries in GCA, which fulfil the OMERACT ultrasound definitions and adhere to the published IMT cut-off values in GCA, is feasible. Ultrasound specialists identified each respective model correctly in every case.