The spectrum of findings in supra-aortic Takayasu's arteritis as seen on spiral CT angiography and digital subtraction angiography

Childhood-Onset Takayasu Arteritis (c-TA): Current and Future Drug Therapy

Childhood-onset Takayasu arteritis (c-TA) is the third most common systemic vasculitic disorder in children. Vascular stenosis is the main complication, and aneurysms are reported in 19-65% of cases, often in combination with stenotic lesions. Management of patients with c-TA is largely based on studies involving predominantly patients with adult-onset TA (a-TA). More widely used criteria for patients with c-TA have been devised by the joint European League Against Rheumatism, Pediatric Rheumatology International Trials Organization, and Pediatric Rheumatology European Society. Of the available imaging modalities, those that do not use radiation (color Doppler ultrasound and magnetic resonance angiogram) are preferred over ¹⁸F-labeled fluoro-2-deoxyglucose (¹⁸F-FDG) positron-emission tomography, computed tomography (CT), and CT angiogram in children. Remission rates have been reported to be lower in c-TA than in a-TA, and published mortality rates in c-TA range from 16 to 40%, which is much higher than reported in patients with a-TA. The usual drug therapy options include steroids plus steroid-sparing second-line immunosuppressants, such as mycophenolate, azathioprine, methotrexate, cyclophosphamide, and cyclosporine, along with antiplatelet agents. Interleukin-6 inhibitors such as tocilizumab, as well as the tumor necrosis factor inhibitors, are other aggressive therapeutic options. As yet, no randomized controlled trials have been conducted in c-TA.

Diagnosis and differential diagnosis of large-vessel vasculitides

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

Application of imaging techniques for Takayasu arteritis

Arterial injury with subsequent remodelling and predisposition to arterial stenosis and/or dilation are the hallmarks of Takayasu arteritis. The degree of arterial damage closely aligns with prognosis and therefore its prevention is the predominant aim of therapy. Non-invasive imaging has greatly improved our ability to identify the extent and severity of disease and to monitor its progress. However, many questions remain concerning the optimal use of individual modalities at different stages of disease. Imaging methods for the quantification of arterial damage are lacking. Likewise, no single technique can accurately determine disease activity within the arterial wall or distinguish inflammatory and non-inflammatory disease progression. The aim of this review is to outline current imaging strategies in Takayasu arteritis, their individual roles in diagnosis and disease monitoring and potential future advances.

Other cerebrovascular occlusive disease

In this chapter we review the optimal imaging modalities for subacute and chronic stroke. We discuss the utility of computed tomography (CT) and multimodal CT imaging. Further, we analyze the importance of specific magnetic resonance imaging sequences, such as diffusion-weighted imaging for acute ischemic stroke, T2/fluid-attenuated inversion recovery for subacute and chronic stroke, and susceptibility imaging for detection of intracranial hemorrhages. Different ischemic stroke mechanisms are reviewed, and how these imaging modalities may aid in the determination of such. Further, we analyze how topographic patterns in ischemic stroke may provide important clues to the diagnosis, in addition to the temporal evolution of the stroke. Lastly, specific cerebrovascular occlusive diseases are reviewed, with emphasis on the optimal imaging modalities and their findings in each condition.

Cardiovascular magnetic resonance in rheumatology: Current status and recommendations for use

Targeted therapies in connective tissue diseases (CTDs) have led to improvements of disease-associated outcomes, but life expectancy remains lower compared to general population due to emerging co-morbidities, particularly due to excess cardiovascular risk. Cardiovascular magnetic resonance (CMR) is a noninvasive imaging technique which can provide detailed information about multiple cardiovascular pathologies without using ionizing radiation. CMR is considered the reference standard for quantitative evaluation of left and right ventricular volumes, mass and function, cardiac tissue characterization and assessment of thoracic vessels; it may also be used for the quantitative assessment of myocardial blood flow with high spatial resolution and for the evaluation of the proximal coronary arteries. These applications are of particular interest in CTDs, because of the potential of serious and variable involvement of the cardiovascular system during their course. The International Consensus Group on CMR in Rheumatology was formed in January 2012 aiming to achieve consensus among CMR and rheumatology experts in developing initial recommendations on the current state-of-the-art use of CMR in CTDs. The present report outlines the recommendations of the participating CMR and rheumatology experts with regards to: (a) indications for use of CMR in rheumatoid arthritis, the spondyloarthropathies, systemic lupus erythematosus, vasculitis of small, medium and large vessels, myositis, sarcoidosis (SRC), and scleroderma (SSc); (b) CMR protocols, terminology for reporting CMR and diagnostic CMR criteria for assessment and quantification of cardiovascular involvement in CTDs; and (c) a research agenda for the further development of this evolving field.

Non-invasive imaging of vascular inflammation

In large-vessel vasculitides, inflammatory infiltrates may cause thickening of the involved arterial vessel wall leading to progressive stenosis and occlusion. Dilatation, aneurysm formation, and thrombosis may also ensue. Activated macrophages and T lymphocytes are fundamental elements in vascular inflammation. The amount and density of the inflammatory infiltrate is directly linked to local disease activity. Additionally, patients with autoimmune disorders have an increased cardiovascular (CV) risk compared with age-matched healthy individuals as a consequence of accelerated atherosclerosis. Molecular imaging techniques targeting activated macrophages, neovascularization, or increased cellular metabolic activity can represent effective means of non-invasive detection of vascular inflammation. In the present review, novel non-invasive imaging tools that have been successfully tested in humans will be presented. These include contrast-enhanced ultrasonography, which allows detection of neovessels within the wall of inflamed arteries; contrast-enhanced CV magnetic resonance that can detect increased thickness of the arterial wall, usually associated with edema, or mural enhancement using T2 and post-contrast T1-weighted sequences, respectively; and positron emission tomography associated with radio-tracers such as [¹⁸F]-fluorodeoxyglucose and the new [¹¹C]-PK11195 in combination with computed tomography angiography to detect activated macrophages within the vessel wall. Imaging techniques are useful in the diagnostic work-up of large- and medium-vessel vasculitides, to monitor disease activity and the response to treatments. Finally, molecular imaging targets can provide new clues about the pathogenesis and evolution of immune-mediated disorders involving arterial vessels.

Takayasu arteritis presenting with massive cerebral ischemic infarction in a 35-year-old woman: a case report

Introduction

Takayasu arteritis is a relatively rare type of large-vessel arteritis that primarily affects the aorta and its major branches, the coronary arteries, and the pulmonary arteries. Depending on the different groups of blood vessels involved in the disease process, the clinical presentation of Takayasu arteritis varies. Here we report a case of a woman presenting with a debilitating massive cerebral ischemic infarct that turned out to be a relatively rare first presentation of Takayasu arteritis.

Case presentation

A 35-year-old Chinese woman presented to the Emergency Department with left hemiparesis, pain and numbness of her arms and weak radial pulses. Her laboratory results showed an elevated C-reactive protein and erythrocyte sedimentation rate, and subsequent digital subtraction angiography demonstrated narrowing and occlusion of the major branches of her aortic arch. We report the case of a patient with Takayasu arteritis presenting with a massive cerebral ischemic infarct and review the current literature on this topic.

Conclusion

Takayasu arteritis is a relatively rare disease with various and sometimes devastating clinical manifestations, such as massive cerebral ischemic infarction as in our case. Currently, there are multiple diagnostic tools and treatment options available, and more under investigation. Early, appropriate diagnosis and initiation of proper therapy could avoid further progression and reduce complications of the disease.

Role of imaging in the diagnosis of large and medium-sized vessel vasculitis

In large-vessel vasculitis, imaging studies are useful to document temporal artery involvement and crucial to show large-vessel involvement. Color Doppler sonography, magnetic resonance, and computed tomography show early vasculitic lesions. Angiography delineates later vascular complications well. Color Doppler sonography, magnetic resonance angiography, and computed tomography angiography can also be used to show vascular luminal changes. Positron emission tomography is very sensitive in detecting large-vessel inflammation. Imaging procedures can also be used to monitor the course of large-vessel vasculitis. In medium-vessel vasculitis, imaging studies can be used to show both vascular changes and internal organ changes.

Advances in the diagnosis, assessment and outcome of Takayasu's arteritis

Takayasu's arteritis (TAK) is a rare, chronic large-vessel vasculitis (LVV) that predominantly affects aorta, its major branches, and the pulmonary arteries. Segmental stenosis, occlusion, dilatation, or aneurysm formation may occur in the vessel wall during the course of the disease. The vascular involvement can be shown with different imaging modalities to make the diagnosis of TAK. Conventional angiography, the gold standard method for initial diagnosis, seems to be replaced with the new imaging modalities such as magnetic resonance angiography (MRA) and (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in recent years. The data coming from the new studies support that MRA and FDG-PET are also promising for the assessment of disease activity. Prognosis is possibly getting better with lower mortality in recent years; however, it is difficult to assess the widely different vascular intervention rates among the clinical series. Leflunomide, TNF-α antagonists, and tocilizumab are new options in patients resistant to conventional therapies. There is a clear need to develop a validated set of outcome measures for use in clinical trials of TAK. The OMERACT Vasculitis Working Group has taken on this task and aims to develop a core set of outcomes for LVV.

Takayasu arteritis--advances in diagnosis and management

Takayasu arteritis, a rare granulomatous vasculitis affecting young people, is associated with considerable morbidity and premature mortality. In most patients the diagnosis is delayed until after the development of substantial arterial injury. Studies of noninvasive imaging techniques suggest that these approaches might facilitate earlier diagnosis and have a role in monitoring disease progress; however, they remain limited in their ability to accurately quantify inflammatory disease activity in the arterial wall. A lack of controlled clinical trial data complicates the choice of therapy for Takayasu arteritis, and clinical indices for monitoring disease activity are currently suboptimal. Increasing knowledge of the pathogenesis of the large vessel vasculitides might eventually lead to novel targeted therapies. Preliminary data from open-label trials of anti-tumor necrosis factor therapy are encouraging, but there is an urgent need for controlled clinical trials to establish optimum therapeutic approaches for this disease. These trials should include a prospective assessment of the use of noninvasive imaging modalities in the diagnosis and subsequent management of Takayasu arteritis.

[Imaging techniques in the evaluation of primary large vessel vasculitides: Part 2: duplex ultrasound, positron emission tomography, computed tomography, and ophthalmological methods]

This article focuses on the clinical application and technical aspects of imaging methods which are used alternatively or additionally to angiography or magnetic resonance imaging in patients with Takayasu's arteritis or giant cell arteritis. Providing a high spatial resolution, duplex ultrasound is particularly suitable for the evaluation of peripheral arteries. With the exception of cranial arteries, positron emission tomography as a whole body examination is the best imaging modality for the assessment of inflammatory activity. Computed tomography is used for angiographic examinations and enables evaluation of wall thickening in large arteries. It is the method of choice in the case of emergencies due to aortic aneurysm or dissection. In addition to angiographic and ultrasound techniques, ophthalmological methods comprise biomicroscopy, including funduscopy and optical coherence tomography.

[Large-vessel vasculitis. Imaging and interventional therapy]

Giant cell arteritis and Takayasu's arteritis are classified as primary large-vessel vasculitides. Inflammatory cell infiltrates and cytokines induce destruction and hyperplasia of the vessel wall, leading to stenoses or aneurysms. When extracranial large arteries are involved, there is often a similar clinical and radiologic disease pattern of an inflammatory aortic arch syndrome. Rare causes of large-vessel vasculitis include Behçet's disease, association with other autoimmune diseases, and infection. Depending on the localization, imaging is usually performed by means of duplex ultrasound, magnetic resonance imaging, computed tomography, or positron emission tomography. These imaging modalities are used not only to establish the diagnosis but also to determine the disease extent and activity and to perform follow-up in the course of medical therapy. Angiography offers the option to perform interventional therapy for vascular stenoses and occlusions.

Takayasu's disease: a review

Takayasu's disease is a rare chronic vasculitis of unknown aetiology. Initial symptoms and signs are non-specific, and a high index of suspicion is needed to make the correct diagnosis. The disease is associated with a high incidence of morbidity, and a significant risk of premature death. Serological tests have proved unreliable in distinguishing active from quiescent disease, with non-invasive imaging currently offering the best option for early diagnosis, and monitoring the response to treatment. In this review, we detail the epidemiology, pathophysiology, clinical features, imaging characteristics, and currently available treatments.

Giant cell arteritis: a systemic vascular disease

Abstract

Giant cell arterits (GCA) is increasingly being recognized as a systemic vascular disease, not confined to the cranial arteries. Epidemiological studies have shown that almost one-third of the patients with GCA develop serious peripheral vascular complications during long-term follow up, and there is growing evidence that unrecognized extracranial involvement may be even more common. GCA of large- and medium-sized peripheral arteries typically leads to long tapering and occlusion of the arterial lumen due to concentric intimal thickening, sometimes accompanied by spontaneous dissection. Depending on the extent of the arterial obliteration and on the anatomy of the involved arterial segment, this may result in severe ischemia of the limbs during the acute phase of the disease. GCA of the aorta usually remains asymptomatic for many years, and leads to a markedly increased risk of aneurysms and dissections, particularly of the thoracic aorta. Evolving vascular imaging techniques such as duplex ultrasound, computer tomography (CT), magnetic resonance imaging (MRI), and fluorine-18-desoxyglucose positron emission tomography (18F-FDG-PET) have greatly improved our ability to detect and study arterial changes in large-artery vasculitis. Boosted by these advances in vascular imaging, vascular specialists are increasingly involved in the early diagnosis, follow-up and treatment of patients with large-vessel vasculitis.

Diagnostic imaging in Takayasu arteritis

PURPOSE OF REVIEW

New imaging modalities may help accurately diagnose and monitor Takayasu arteritis (TAK). Examination of the published literature on arterial imaging studies other than conventional angiography will help guide appropriate use of these studies in TAK. MRI, magnetic resonance angiography (MRA), Doppler ultrasound, CT, and positron emission tomography (PET) are all potentially useful for evaluation of TAK.

RECENT FINDINGS

MRI/A avoids the risks of arterial puncture, iodinated contrast load, and radiation exposure, while providing information on arterial wall anatomy and obtaining a generalized arterial survey in TAK. Ultrasound can be helpful in detecting sub-millimeter changes in wall thickness of the carotid arteries and in differentiating TAK from atherosclerotic disease based on minimal plaque content, concentric and long segmental involvement, and location of lesion. Like MRI, CT angiography can be used to detect areas of aortic wall thickening and obtain a generalized survey of the aorta and its proximal branches for areas of stenosis and without the risks associated with arterial puncture. However, CT provides less detailed resolution than ultrasound and incurs the risks of contrast administration. Finally, PET scanning may provide valuable information about cellular activity within an inflamed arterial wall before morphologic changes on other imaging studies.

SUMMARY

Although it is still unclear how often early arterial wall changes lead to stenotic lesions, use of these modalities in combination, for both routine monitoring and evaluation of new symptoms, may facilitate the detection of TAK disease activity at a more treatable stage.