Takayasu arteritis: diagnosis with MR imaging and MR angiography in acute and chronic active stages

A review of histopathologic and radiologic features of non-atherosclerotic pathologies of the extracranial carotid arteries

Diseases of the carotid arteries can be classified into different categories based on their origin. Atherosclerotic carotid disease remains the most encountered arterial wall pathology. However, other less-common non-atherosclerotic diseases can have detrimental clinical consequences if not appropriately recognized. The underlying histological features of each disease process may result in imaging findings that possess features that are obvious of the disease. However, some carotid disease processes may have histological characteristics that manifest as non-specific radiologic findings. The purpose of this manuscript is to review various non-atherosclerotic causes of carotid artery disease as well as their histologic-radiologic characteristics to aid in the appropriate recognition of these less-commonly encountered pathologies.

Multimodality Evaluation of Aortic Insufficiency and Aortitis in Rheumatologic Diseases

Aortic insufficiency is commonly observed in rheumatologic diseases such as ankylosing spondylitis, systemic lupus erythematosus, antiphospholipid syndrome, Behçet's disease, granulomatosis with polyangiitis, and Takayasu arteritis. Aortic insufficiency with an underlying rheumatologic disease may be caused by a primary valve pathology (leaflet destruction, prolapse or restriction), annular dilatation due to associated aortitis or a combination of both. Early recognition of characteristic valve and aorta morphology on cardiac imaging has both diagnostic and prognostic importance. Currently, echocardiography remains the primary diagnostic tool for aortic insufficiency. Complementary use of computed tomography, cardiac magnetic resonance imaging and positron emission tomography in these systemic conditions may augment the assessment of underlying mechanism, disease severity and identification of relevant non-valvular/extracardiac pathology. We aim to review common rheumatologic diseases associated with aortic insufficiency and describe their imaging findings that have been reported in the literature.

Overview of imaging in adult- and childhood-onset Takayasu arteritis

Takayasu Arteritis is an idiopathic large vessel vasculitis, that affects young adults and children and can lead to ischemia and end-organ damage. Vascular imaging is crucial for diagnosis, assessment of disease extent and management of the disease. In this article, we critically review evidence for the clinical use of the different imaging modalities conventional angiography, magnetic resonance imaging, computed tomography, Doppler ultrasound and ¹⁸fluorodeoxyglucose positron emission tomography. We thereby focus on their clinical applicability, challenges and specific use in children.

Current Clinical Applications of Intracranial Vessel Wall MR Imaging

Intracranial vessel wall MR imaging (VWI) is increasingly being used as a valuable adjunct to conventional angiographic imaging techniques. This article will provide an updated review on intracranial VWI protocols and image interpretation. We review VWI technical considerations, describe common VWI imaging features of different intracranial vasculopathies and show illustrative cases. We review the role of VWI for differentiating among steno-occlusive vasculopathies, such as intracranial atherosclerotic plaque, dissections and Moyamoya disease. We also highlight how VWI may be used for the diagnostic work-up and surveillance of patients with vasculitis of the central nervous system and cerebral aneurysms.

Aortitis - An Interdisciplinary Challenge

The term 'aortitis' comprises a heterogeneous spectrum of diseases, with varied etiology and clinical presentations, whose common characteristic is the inflammation of the aortic wall. Since aortitis can mimic almost all common cardiovascular disorders, its clinical recognition remains a challenge. Some cases of aortitis remain undetected for a long time and may be diagnosed after severe life-threatening complications have already arisen. The diagnosis of aortitis is based on the presence of homogeneous circumferential thickening of the aortic wall detected on aortic imaging, or typical histological features in combination with clinical findings and laboratory parameters. Management of aortitis is usually conservative (immunosuppressive drugs in noninfectious aortitis; antimicrobial drugs in infectious). However, if vascular complications such as aortic aneurysm, rupture, or steno-occlusive events appear, aortic surgery or endovascular therapy may be required. This review article summarizes the current knowledge regarding the etiology, clinical presentation, diagnosis, and treatment of inflammatory diseases of the aorta to promote better clinical management of these entities.

Vessel wall MR imaging of central nervous system vasculitis: a systematic review

PURPOSE

Beyond vessel wall enhancement, little is understood about vessel wall MR imaging (VW-MRI) features of vasculitis affecting the central nervous system (CNS). We reviewed vessel wall MR imaging patterns of inflammatory versus infectious vasculitis and also compared imaging patterns for intracranial versus extracranial arteries of the head and neck.

METHODS

Studies reporting vasculitis of the CNS/head and neck and included MR imaging descriptions of vessel wall features were identified by searching PubMed, Scopus, Cochrane, Web of Science, and EMBASE up to June 10, 2020. From 6065 publications, 115 met the inclusion criteria. Data on study characteristics, vasculitis type, MR details, and VW-MRI descriptions were extracted.

RESULTS

Studies used VW-MRI for inflammatory (64%), infectious (17%), or both inflammatory and infectious vasculitides (19%). Vasculitis affecting intracranial versus extracranial arteries were reported in 58% and 39% of studies, respectively. Commonly reported VW-MRI features were vessel wall enhancement (89%), thickening (72%), edema (10%), and perivascular enhancement (16%). Inflammatory vasculitides affecting the intracranial arteries were less frequently reported to have vessel wall thickening (p = 0.006) and perivascular enhancement (p = 0.001) than extracranial arteries. Varicella zoster/herpes simplex vasculitis (VZV/HSV, 45%) and primary angiitis of the CNS (PACNS, 22%) were the most commonly reported CNS infectious and inflammatory vasculitides, respectively. Patients with VZV/HSV vasculitis more frequently showed decreased or resolution of vessel wall enhancement after therapy compared to PACNS (89% versus 59%).

CONCLUSIONS

To establish imaging biomarkers of vessel wall inflammation in the CNS, VW-MRI features of vasculitis accounting for disease mechanism and anatomy should be better understood.

Beyond plaque: A pictorial review of non-atherosclerotic abnormalities of extracranial carotid arteries

The common carotid artery (CCA) and extracranial internal carotid artery are subject to a wide variety of non-atheromatous pathologies. These entities are often overshadowed in both research and clinical realms by atherosclerotic disease. Nevertheless, non-atherosclerotic disease of the carotid arteries may have profound, even devastating, neurologic consequences. Hence, this review will cover both common and uncommon forms of extracranial carotid artery pathologies in a pictorial format, in order to aid the diagnostician in identifying and differentiating such pathologies.

Cardiovascular magnetic resonance in the diagnosis and management of cardiac and vascular involvement in the systemic vasculitides

PURPOSE OF REVIEW

Cardiac manifestations in systemic vasculitides, either primary or secondary due to infection, malignancy or autoimmune rheumatic diseases may be life-threatening. Cardiovascular (CVD) magnetic resonance (CMR) has been recently proposed as an ideal noninvasive tool to evaluate systemic vasculitides. In the present article, we present an overview of CMR in the diagnosis and follow-up of cardiac involvement in systemic vasculitides.

RECENT FINDINGS

CMR is a noninvasive, nonradiating modality, capable to assess cardiac function, perfusion and tissue characterization that can be of great diagnostic value in both primary and secondary systemic vasculitides. It has been already documented that CMR is superior to other imaging modalities, because it has great versatility and higher spatial resolution that allows the detection of early CVD phenomena occurring during systemic vasculitides. Magnetic resonance angiography and oedema-fibrosis imaging detect early CVD involvement such as acute and/or chronic inflammation, coronary macro-micro-circulation abnormalities and/or small vessel vasculitis.

SUMMARY

CMR due to its great versatility gives valuable information about cardiac function, perfusion, type of fibrosis and vascular integrity that may significantly contribute to treatment decisions beyond vascular scores, other disease activity or severity indices or the acute phase response.

Detection of Inflammatory Aortopathies Using Multimodality Imaging

Diagnosis of the inflammatory aortopathies and importantly, their distinction in the later stages of disease from genetically mediated or acquired (degenerative) aortopathy remains a challenging clinical problem. Historically, the diagnosis of inflammatory aortopathy has required tissue sampling and pathological assessment. Although histological diagnosis remains an important diagnostic criterion, the ability to obtain sufficient tissue samples is problematic and requires invasive approaches that pose important risk. Continuing refinement in the capabilities of multimodality imaging, including ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography provides important insights into the broad spectrum of disease which comprise the inflammatory aortopathies. This review examines the current and emerging role of multimodality imaging in the evaluation of aortitis.

Advances in Therapies and Imaging for Systemic Vasculitis

Vasculitis is a systemic disease characterized by immune-mediated injury of blood vessels. Current treatments for vasculitis, such as glucocorticoids and alkylating agents, are associated with significant side effects. Furthermore, the management of both small and large vessel vasculitis is challenging because of a lack of robust markers of disease activity. Recent research has advanced our understanding of the pathogenesis of both small and large vessel vasculitis, and this has led to the development of novel biologic therapies capable of targeting key cytokine and cellular effectors of the inflammatory cascade. In parallel, a diverse range of imaging modalities with the potential to monitor vessel inflammation are emerging. Continued expansion of combined structural and molecular imaging using positron emission tomography with computed tomography or magnetic resonance imaging may soon provide reliable longitudinal tracking of vascular inflammation. In addition, the emergence of radiotracers able to assess macrophage activation and immune checkpoint activity represents an exciting new frontier in imaging vascular inflammation. In the near future, these advances will allow more precise imaging of disease activity enabling clinicians to offer more targeted and individualized patient management.

Evaluation of takayasu arteritis with delayed contrast-enhanced MR imaging by a free-breathing 3D IR turbo FLASH

The primary aim of our case-control study was to observe delayed contrast-enhanced magnetic resonance imaging (DCE-MRI) in patients with Takayasu arteritis (TA) in comparison with magnetic resonance angiography (MRA). Twenty-seven patients including 15 with active TA and 12 with stable TA who underwent both aortic MRA and DCE-MRI were included. A total of 27 sex- and age-matched healthy volunteers were enrolled as the control group. MRA were obtained with T1WI-volume-interpolated breath-hold examination sequence or fast low-angle shot (FLASH) sequence. DCE-MRI was acquired with a free-breathing three-dimensional inversion recovery Turbo fast low-angle shot (3D IR Turbo FLASH). Neither stenosis nor delayed enhancement of arterial wall was shown in the control group. In patients with stable TA, arterial stenosis was observed on MRA. On DCE-MR, delayed enhancement of arterial walls could be observed in the active TA group but not in the stable TA group or the control group. Stenotic arteries on MRA were comparable in the active TA and stable TA (χ = 2.70, P = .259); however, delayed enhancement of arterial walls in the active-TA group were more than those in the stable group (χ = 27.00, P < .001). Our results suggest that DCE-MRI with the free-breathing 3D IR Turbo FLASH sequence could assess TA and delayed enhancement on DCE-MRI is one characteristics of the active TA.

Intracranial Vessel Wall MRI: Principles and Expert Consensus Recommendations of the American Society of Neuroradiology

Intracranial vessel wall MR imaging is an adjunct to conventional angiographic imaging with CTA, MRA, or DSA. The technique has multiple potential uses in the context of ischemic stroke and intracranial hemorrhage. There remain gaps in our understanding of intracranial vessel wall MR imaging findings and research is ongoing, but the technique is already used on a clinical basis at many centers. This article, on behalf of the Vessel Wall Imaging Study Group of the American Society of Neuroradiology, provides expert consensus recommendations for current clinical practice.

Wall enhancement on high-resolution magnetic resonance imaging may predict an unsteady state of an intracranial saccular aneurysm

INTRODUCTION

The aneurysm wall has been reported to play a critical role in the formation, development, and even rupture of an aneurysm. We used high-resolution magnetic resonance imaging (HRMRI) to investigate the aneurysm wall in an effort to identify evidence of inflammation invasion and define its relationship with aneurysm behavior.

METHODS

Patients with intracranial aneurysms who were prospectively evaluated using HRMRI between July 2013 and June 2014 were enrolled in this study. The aneurysm's wall enhancement and evidence of inflammation invasion were determined. In addition, the relationship between aneurysm wall enhancement and aneurysm size and symptoms, including ruptured aneurysms, giant unruputred intracranial aneurysms (UIAs) presenting as mass effect, progressively growing aneurysms, and aneurysms associated with neurological symptoms, was statistically analyzed.

RESULTS

Twenty-five patients with 30 aneurysms were available for the current study. Fourteen aneurysms showed wall enhancement, including 6 ruptured and 8 unruptured aneurysms. Evidence of inflammation was identified directly through histological studies and indirectly through intraoperative investigations and clinical courses. The statistical analysis indicated no significant correlation between aneurysm wall enhancement and aneurysm size. However, there was a strong correlation between wall enhancement and aneurysm symptoms, with a kappa value of 0.86 (95 % CI 0.68-1).

CONCLUSIONS

Aneurysm wall enhancement on HRMRI might be a sign of inflammatory change. Symptomatic aneurysms exhibited wall enhancement on HRMRI. Wall enhancement had a high consistent correlation of symptomatic aneurysms. Therefore, wall enhancement on HRMRI might predict an unsteady state of an intracranial saccular aneurysm.

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.

Increasing echogenicity of diffuse circumferential thickening ("macaroni sign") of the carotid artery wall with decreasing inflammatory activity of Takayasu arteritis

We report a case of sonographic follow-up showing brightening of the diffuse circumferential thickening (halo) of the carotid artery wall (the so-called "macaroni sign") in a patient with decreasing inflammatory activity of Takayasu arteritis over a 6-month period. Sonographic follow-up in patients with Takayasu arteritis may be a useful complementary tool for evaluation of inflammatory activity. Besides a reduction of halo diameter, an increase in wall echogenicity appears to be a sign of decreasing inflammation.

[Clinical indications for the use of cardiac MRI. By the SIRM Study Group on Cardiac Imaging]

Cardiac magnetic resonance (CMR) is considered an useful method in the evaluation of many cardiac disorders. Based on our experience and available literature, we wrote a document as a guiding tool in the clinical use of CMR. Synthetically we describe different cardiac disorders and express for each one a classification, I to IV, depending on the significance of diagnostic information expected.

Imaging of thoracic aortic disease

Aortic pathology can be more complex to understand on imaging than is initially appreciated. There are a number of imaging modalities that provide excellent assessment of aortic pathology and enable the accurate monitoring of disease. This review discusses the imaging of the most common disease processes that affect the aorta in adults, with the primary focus being on CT and MRI.

Sudden mono-ocular blindness with recurrent transient diplopia and ptosis in a middle-aged woman

Sudden painless loss of vision is an ophthalmologic and a medical emergency resulting from various causes such as occlusion of retinal artery or vein, macular or vitreous haemorrhages, retinal detachment, and anterior and posterior ischaemic optic neuropathy. We report a 48-year-old woman presenting with right monocular blindness due to branch retinal artery occlusion whose vision recovered due to timely paracentesis coupled with treatment with adequate antiplatelet agents and anticoagulants. The patient had transient diplopia and ptosis despite adequate antiplatelet agents and anticoagulants. Thorough search for aetiology revealed the underlying cause to be aortoarteritis. Aortoarteritis is a rare disease, and ocular involvement occurs late in the disease. We review ophthalmologic manifestation of aortoarteritis and diagnostic utilities of various modalities for aortoarteritis.

Cardio-ankle vascular index for evaluating immunosuppressive therapy in a patient with aortitis syndrome

Aortitis syndrome is a chronic vasculitis that leads to arterial wall thickening and stiffening in large elastic arteries. However, there are no established markers for assessing arterial stiffening in aortitis syndrome. The cardio-ankle vascular index (CAVI) has recently been utilized to assess arterial stiffening that is associated with atherosclerosis-related diseases. We hypothesized that CAVI can be applicable for assessing alterations in arterial stiffness during immunosuppressive therapy for aortitis syndrome. A 69-year-old woman with a 2-month history of recurrent fever, fatigue, and malaise, showed intense 18F-fluorodeoxyglucose (18F-FDG) uptake in the thoracic aorta and common carotid arteries in 18F-FDG-positron emission tomography. These clinical and imaging findings resulted in the diagnosis of aortitis syndrome. The patient also showed the elevated CAVIs on both sides (right, 10.3; left, 10.4) (normal value for her age, 9.1 +/- 0.8), indicating the arterial stiffness due to aortitis syndrome. The patient was treated for 34 weeks with immunosuppressive therapy, which included oral prednisolone and methotrexate. C-reactive protein (from 4.24 to 0.49 mg/dL) and immunoglobulin G (from 2,627 to 1,524 mg/dL) were decreased by 7 weeks after initiation of the treatment. The decrease in these inflammatory parameters suggests the effectiveness of the immunosuppressive therapy. In addition, after the 34-week treatment, the CAVIs on both sides (right, 9.3; left, 9.2) were within the normal range. These data indicate that the immunosuppressive therapy ameliorates the degree of arterial stiffness. In conclusion, CAVI may be a promising marker for evaluating the effectiveness of immunosuppressive therapy in patients with aortitis syndrome.

Detection of increased arterial stiffness in a patient with early stage of large vessel vasculitis by measuring cardio-ankle vascular index

Large vessel vasculitis leads to arterial wall thickening and stiffening because of chronic inflammatory changes. The cardio-ankle vascular index (CAVI) is recently utilized for assessing arterial stiffening caused by atherosclerosis-related diseases, including hypertension and diabetes, as well as aging. CAVI is mathematically calculated from stiffness index beta, which is established as a parameter of arterial stiffness independent of blood pressure. However, there are no data regarding arterial stiffness assessed by CAVI for large vessel vasculitis. We describe a patient with large vessel vasculitis who showed aortic wall thickening and increased CAVI without hypertension. A 68-year-old woman presented at our hospital with recurrent fever of 2-month duration, fatigue, neck pain, and weight loss. The images of 18F-fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) demonstrated significant 18FDG uptake (indicating increased metabolic activity and presence of inflammation) in the aorta and its major branches, including the carotid and subclavian arteries. Contrast-enhanced magnetic resonance imaging demonstrated wall thickening of the thoracic aorta. These imaging findings resulted in the diagnosis of large vessel vasculitis. The patient showed normal brachial blood pressure (right, 122/72 and left, 121/66 mmHg). However, CAVIs on both sides (right, 10.3 and left, 10.4) were elevated (normal value for her age, 9.1 +/- 0.8). In conclusion, arterial stiffness in patients with large vessel vasculitis may be increased because of the arterial wall thickening and inflammatory changes. Thus, CAVI may be promising for detection of increased arterial stiffness in patients with large vessel vasculitis in the early stage, in which blood pressure is normal.

Endovascular Management of Takayasu Arteritis: Is It a Durable Option?

Interim outcome of endovascular management of Takayasu arteritis (TA) was determined retrospectively to assess the efficacy of angioplasty and/or stenting in 24 patients with 35 lesions in the chronic inactive stage. The renal ( n = 16), subclavian/innominate ( n = 11), and carotid ( n = 5) arteries and abdominal aorta ( n = 3) were treated. Twenty-six lesions achieved excellent to good target lesion revascularization with no residual or only minimal residual stenosis, whereas five had a moderate result. Thirty lesions achieved satisfactory hemodynamic correction. Restenosis was observed in 8 lesions treated with angioplasty alone ( n = 18) and in 3 lesions treated with angioplasty and stenting ( n = 17). All recurrent stenoses underwent successful reintervention without significant complication. Treatment of inactive stage TA lesions with angioplasty alone or with angioplasty and stenting results in excellent to good clinical improvement in the majority of patients (follow-up at 46.8 months). Endovascular therapy is a durable treatment option in patients with chronic inactive stage TA.

Imaging for large-vessel vasculitis

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Assessment of systemic vasculitis

The systemic vasculitides are an uncommon group of autoimmune diseases capable of causing multi organ failure and death. Current immunosuppressive strategies have substantially improved the outcome, but the natural history of treated disease is unstable, typically characterised by frequent relapses, drug toxicity and an increasing burden of damage. Early diagnosis, accurate staging and regular evaluation of disease status are important in the management of the vasculitides. Clinical evaluation tools have been developed and provide a comprehensive assessment of patients. Serological markers, especially anti-neutrophil cytoplasm antibody (ANCA), pathology and imaging investigations are a useful addition, but are more valuable in diagnosis rather than monitoring of disease activity. Advances in magnetic resonance imaging in large vessel vasculitis have improved our ability to characterise disease and may lead to earlier diagnosis and better control in future. Development of new biomarkers is required in vasculitis, and this is likely to advance our understanding as well as the management of these complex conditions.

Advances in clinical applications of cardiovascular magnetic resonance imaging

Cardiovascular magnetic resonance (CMR) is an evolving technology with growing indications within the clinical cardiology setting. This review article summarises the current clinical applications of CMR. The focus is on the use of CMR in the diagnosis of coronary artery disease with summaries of validation literature in CMR viability, myocardial perfusion, and dobutamine CMR. Practical uses of CMR in non-coronary diseases are also discussed.

Diagnostic value of high-resolution MR imaging in giant cell arteritis

BACKGROUND AND PURPOSE

Clinical indications of giant cell arteritis may be unspecific, and noninvasive diagnosis is often difficult. This study investigated the hypothesis that high-resolution MR imaging of the superficial cranial arteries is a noninvasive imaging technique that can detect the occurrence of giant cell arteritis.

MATERIALS AND METHODS

Contrast-enhanced, high-resolution MR imaging was performed on 64 consecutive patients with suspected giant cell arteritis. Mural thickness, lumen diameter, and a mural contrast enhancement score were assessed with T1-weighted spin-echo images with submillimeter in-plane spatial resolution. The final rheumatologist's diagnosis according to the clinical criteria of the American College of Rheumatology including laboratory tests and results of temporal artery biopsies from 32 patients was used as a "gold standard" for the evaluation of the MR imaging findings.

RESULTS

All of the examinations provided diagnostic image quality. Evaluation of the mural inflammatory MR imaging signs for diagnosing vasculitis resulted in a sensitivity of 80.6% and a specificity of 97.0%. In comparison, histology results alone showed a sensitivity of 77.8% and specificity of 100%. The mean wall thickness increased significantly from 0.39 mm (+/-0.18 mm) to 0.74 mm (+/-0.32 mm; P < .001), and the lumen diameter decreased significantly from 0.84 mm (+/-0.29 mm) to 0.65 mm (+/-0.38 mm; P < .05) for patients with giant cell arteritis.

CONCLUSION

Contrast-enhanced, high-resolution MR imaging allows noninvasive assessment of mural inflammation in giant cell arteritis with good diagnostic certainty. Measures of mural thickening and contrast enhancement can be obtained in these small vessels and provide valuable vasculitic MR imaging findings.

[18F]fluorodeoxyglucose positron emission tomography is a useful tool to diagnose the early stage of Takayasu's arteritis and to evaluate the activity of the disease

Takayasu's arteritis (TA) is a rare disease that can be difficult to diagnose in its early stage. A young woman with a fever and neck pain was thought to have TA, although computed tomographic angiography did not show any specific changes of the arteries. [(18)F]fluorodeoxyglucose positron emission tomography ([(18)F]FDG-PET) was performed to detect the source of the inflammation. Specific accumulation of [(18)F]FDG-6-phosphate in the thoracic aorta and its direct branches was observed, leading to a diagnosis of TA. [(18)F]FDG-PET is therefore considered to be useful for the diagnosis of early-stage TA.

Influence of corticosteroid treatment on MRI findings in giant cell arteritis

Giant cell arteritis (GCA) remains a diagnostic challenge. With the use of a high-resolution MRI protocol, visualization of the superficial cranial arteries is feasible and mural inflammation can be assessed noninvasively. Until today, it is not known how soon inflammatory signals in diagnostic MR imaging vanish after initiation of treatment. Here, we report sequential MR imaging findings during the initial weeks of corticosteroid treatment in a 79-year-old female patient with histologically proven GCA. Mural inflammatory changes decreased within the first 2 weeks and have almost entirely vanished after 2 1/2 months of continued treatment. Moreover, MR angiography revealed sequential stenoses of the subclavian artery, which improved in variable extent with some residuals despite high dose steroid medication. This report underlines the value of high-resolution MRI in diagnosis and follow-up of GCA and illustrates the potential of MRI to detect and monitor intra- and extra-cranial involvement patterns of GCA in high detail.

Takayasu arteritis: Role of cardiovascular magnetic imaging

Takayasu arteritis (TA) is a primary arteritis of unknown cause that commonly affects the aorta and its main branches. Traditionally, X-ray contrast angiography has been the gold standard for diagnosis and review of this chronic disease but recent developments suggest that non-invasive imaging with multiplanar cardiovascular magnetic resonance imaging (CMR) and magnetic resonance angiography (MRA) have a number of advantages for use in routine care. This review utilises a series of cases referred for imaging at the Royal Brompton Hospital, London to illustrate these points of development.

Reduced aortic elastic properties in a child with Takayasu arteritis: case report and literature review

Takayasu arteritis (TA) is a chronic inflammatory vasculitis of the aorta and its major branches with a very low incidence in Europe and North America. Our objective was to determine the elastic properties of the affected ascending and descending aortic walls non-invasively in a 14-year-old Iraqi girl with a 3-year history of fever, fatigue, malaise and diffuse pain. Ultrasound and magnetic resonance angiography showed marked thickening of the aortic wall, dilatation of the aortic arch, and decreased luminal diameters of the abdominal aorta and both subclavian arteries, consistent with TA. Ascending and descending aortic elastic properties such as distensibility and stiffness index were markedly reduced compared to a group of healthy controls (n=39): ascending aortic distensibility was 20 kPa(-1) x 10(-3) versus 63+/-23 kPa(-1) x 10(-3) in controls, and the ascending aortic stiffness index 9.6 versus 3.5+/-1.3 in controls. Although the patient's general condition improved rapidly on oral prednisolone and azathioprine and inflammatory parameters normalised within 3 weeks, the aortic elastic parameters did not change during the first 2 weeks of anti-inflammatory treatment. Unfortunately, no further follow-up was possible.

CONCLUSION

In patients with Takayasu arteritis, non-invasive quantification of reduced aortic elastic properties can help to assess aortic involvement, and possibly to follow disease activity and vascular response to therapy.

Acquired diseases of the thoracic aorta: role of MRI and MRA

Diseases of the thoracic aorta can present with a broad clinical spectrum of symptoms and signs. Their prevalence appears to be increasing in western populations, most likely corresponding to aging and heightened clinical awareness but also influenced by the progress of high-resolution, noninvasive imaging modalities. Among them, MRI provides an excellent visualization of vascular structures and is well suited for evaluation of thoracic aorta disease. Currently, in many centers, noninvasive imaging modalities are the first choice in the cardiovascular system evaluation and diagnosis, reserving conventional angiography for use only before therapeutic intervention. Understanding the principle MRA techniques is essential for acquiring consistent diagnostic images. Basic technical considerations, which include fast spin-echo, fast gradient-echo, and MRA techniques with phase contrast and contrast-enhanced methods, are discussed and applied in the evaluation of acquired thoracic aorta diseases.

Role of magnetic resonance imaging in the early diagnosis of Takayasu arteritis

Takayasu arteritis is a non-specific inflammatory process of unknown aetiology affecting the aorta and its major branches. It may lead to stenosis or occlusion. We have examined eight patients with clinically diagnosed Takayasu arteritis using contrast-enhanced MRI and also 3-D MR angiography. All patients were female and their ages varied between 22 and 48 years. We were able to show subtle arteritic changes and stenotic lesions in branch vessels in the early phase of the disease by using this imaging modality. Thus, we can state that contrast-enhanced MRI with 3-D MR angiography can be used for the initial diagnosis of Takayasu arteritis. It provides a means to evaluate the vascular tree non-invasively and may replace conventional angiography.

Integrated head-thoracic vascular MRI at 3 T: Assessment of cranial, cervical and thoracic involvement of giant cell arteritis

Recently, high-resolution contrast-enhanced MRI has proven to be feasible for noninvasive diagnosis of giant cell arteritis in the cranium. In such examinations, thickening of the vessel wall and/or increased contrast enhancement demonstrate mural inflammation. Typically, the superficial cranial arteries with predominance of the superficial temporal artery are affected by the disease. However, giant cell arteritis can also involve other parts of the vascular system and an examination with extended coverage, including head, neck, and thorax would be advantageous. In this study, a novel approach for integrated head-thoracic vascular MRI at 3 T is presented. Combining first-pass imaging of a single-dose contrast agent with post-contrast imaging permits the assessment of both thoracic aortic geometry and wall, in addition to high-resolution head imaging needed for the analysis of the small superficial cranial arteries. Results from a patient feasibility study are presented and confirm that the protocol can successfully be completed in less than 40 min.

Delayed Contrast-Enhanced MRI of the Aortic Wall in Takayasu's Arteritis: Initial Experience

OBJECTIVE

Delayed contrast-enhanced MRI is increasingly being used for cardiac viability imaging. Takayasu's arteritis is a rare inflammatory disorder of unknown cause that affects the aorta, its major branches, and the pulmonary artery; it is characterized by inflammation and fibrosis in the arterial wall. We report our initial experience with seven patients (six women, one man; age range, 25-62 years) with delayed (20 min) gadolinium-enhanced MRI (inversion recovery prepared gated fast gradient-echo pulse sequence) in patients with known Takayasu's arteritis.

CONCLUSION

Patients with Takayasu's arteritis (particularly those with abnormal laboratory values) have evidence of delayed hyper-enhancement on delayed contrast-enhanced MRI. Thus, delayed contrast-enhanced MRI might be a useful technique to identify inflammation in arterial wall.

High-Resolution MRI in Giant Cell Arteritis: Imaging of the Wall of the Superficial Temporal Artery

OBJECTIVE

This study investigated the hypothesis that high-resolution MRI can reveal mural inflammatory changes of the superficial temporal artery in giant cell arteritis (GCA).

SUBJECTS AND METHODS

MRI of the temporal artery of 20 patients with suspected GCA was performed on a 1.5-T scanner using a dedicated eight-element phased-array head coil. Contrast-enhanced multislice T1-weighted spin-echo sequences were acquired perpendicular to the orientation of the vessel, with a submillimeter spatial resolution of 0.2 x 0.3 mm and a slice thickness of 3 mm. Mural thickness and lumen diameter of the temporal artery were measured, and mural contrast enhancement was graded on a four-point scale by two radiologists. For all patients, the MRI results were compared with the findings of clinical examination and laboratory tests. In addition, biopsy samples of the temporal artery were taken from 16 of these patients.

RESULTS

MRI sharply demonstrated the superficial temporal artery, allowing an evaluation of its lumen and wall. Seventeen patients were GCA-positive according to criteria of the American College of Rheumatology. Of these 17, 16 had true-positive MRI findings and one had false-negative MRI findings. The 3 patients who were GCA-negative according to the American College of Rheumatology criteria had true-negative MRI findings. The mean thickness of the vessel wall and the lumen diameter were 0.88 +/- 0.23 mm and 0.78 +/- 0.29 mm, respectively, in GCA-positive patients and 0.57 +/- 0.25 mm and 0.7 +/- 0.1 mm, respectively, in GCA-negative patients.

CONCLUSION

High-resolution contrast-enhanced MRI of the temporal artery allowed visualization of the temporal artery and evaluation of possible inflammation of the vessel wall. Our initial results with this noninvasive technique agreed well with histologic results and with the clinical criteria of the American College of Rheumatology.

Vascular imaging

Many rheumatic diseases affect the vasculature, either as a 'primary' manifestation of the disease process (as in vasculitis or scleroderma-spectrum disorders) or as a result of accelerated atherosclerosis. Recent years have seen very major developments in, and refinements of, vascular imaging methods. It is likely that this pace of development will continue, enhancing the rheumatologist's ability to diagnose different musculoskeletal conditions and follow their progression, using minimally invasive techniques. In this chapter, we describe these recent advances in vascular imaging techniques, concentrating on those most relevant to the practising clinician, but also discussing methods which are being used in clinical research. Three main groups of imaging modalities are described: large vessel imaging (X-ray, magnetic resonance (MR) and computed tomography (CT) angiography), nailfold microscopy and thermography. For each of these, the method(s) and then the clinical and research applications are discussed. Laser Doppler, a research technique, is also described.