The role of B-mode ultrasonography and electron beam computed tomography in evaluation of Takayasu's arteritis: a study of 43 patients

Ultrasound Examination of Common Carotid Adventitial Thickness Can Differentiate Takayasu Arteritis and Large Vessel Giant Cell Arteritis

Pathological studies have demonstrated that the adventitial layer is markedly thickened in Takayasu (TAK) as compared to large vessel giant cell arteritis (LV-GCA). An ultrasound (US) examination of the arterial vessels allows the determination of intima media thickness (IMT) and of adventitial layer thickness (extra media thickness (EMT)). No previous study has evaluated if there are differences in EMT thickness between TAK and LV-GCA. In this cross-sectional retrospective study of stored ultrasound (US) imaging, we have compared common carotid artery (CCA) EMT and IMT in a series of consecutive TAK and LV-GCA patients. US examination CCA IMT and EMT were significantly higher in TAK as compared to LV-GCA. With ROC curve analysis, we have found that an EMT > 0.76 mm has high sensitivity and specificity for TAK CCA examination. The percentage of CCA at EMT > 0.76 mm and the total arterial wall thickening were significantly higher in TAK group examinations. EMT thickness correlated with disease duration and IMT in the TAK group, as well as with the IMT and ESR values in the LV-GCA group. Upon multivariate logistic regression analysis, factors independently associated with TAK CCA were EMT > 0.76 mm and age. No significant variation in IMT and EMT could be demonstrated in subsequent US CCA examinations.

Outcome Measures and Biomarkers for Disease Assessment in Takayasu Arteritis

Takayasu arteritis (TAK) is a less common large vessel vasculitis where histopathology of involved arteries is difficult to access except during open surgical procedures. Assessment of disease activity in TAK, therefore, relies on surrogate measures. Clinical disease activity measures such as the National Institutes of Health (NIH) score, the Disease Extent Index in TAK (DEI.TAK) and the Indian TAK Clinical Activity Score (ITAS2010) inconsistently associate with acute phase reactants (APRs). Computerized tomographic angiography (CTA), magnetic resonance angiography (MRA), or color Doppler Ultrasound (CDUS) enables anatomical characterization of stenosis, dilatation, and vessel wall characteristics. Vascular wall uptake of 18-fluorodeoxyglucose or other ligands using positron emission tomography computerized tomography (PET-CT) helps assess metabolic activity, which reflects disease activity well in a subset of TAK with normal APRs. Angiographic scoring systems to quantitate the extent of vascular involvement in TAK have been developed recently. Erythrocyte sedimentation rate and C-reactive protein have a moderate performance in distinguishing active TAK. Numerous novel biomarkers are under evaluation in TAK. Limited literature suggests a better assessment of active disease by combining APRs, PET-CT, and circulating biomarkers. Validated damage indices and patient-reported outcome measures specific to TAK are lacking. Few biomarkers have been evaluated to reflect vascular damage in TAK and constitute important research agenda.

Headache and temporal arteritis: when to suspect and how to manage

Temporal arteritis, also termed giant cell arteritis, is one of the vasculitides affecting large and medium sized cranial arteries, particularly of the carotid tree. Clinical manifestations may vary from the classic constellation of temporal headache in the elderly accompanied by constitutional signs, jaw claudication, and visual symptoms; therefore, a high index of clinical suspicion may be necessary to identify the disorder. Once suspected, immediate treatment is crucial while exploring any number of diagnostic tools to confirm or refute the diagnosis, since morbidity from untreated temporal arteritis can be devastating. At the same time, achieving a definitive diagnosis is paramount, as treatment can be toxic with significant morbidity of its own. Temporal artery biopsy remains the gold standard, but noninvasive diagnostic approaches are being refined. Corticosteroids remain the cornerstone of treatment, but are ineffective for, not tolerated by, or contraindicated in some individuals, necessitating the exploration of alternatives.

Time to focus on outcome assessment tools for childhood vasculitis

Childhood systemic vasculitides are a group of rare diseases with multi-organ involvement and potentially devastating consequences. After establishment of new classification criteria (Ankara consensus conference in 2008), it is now time to establish measures for proper definition of activity and damage in childhood primary vasculitis. By comparison to adult vasculitis, there is no consensus for indices of activity and damage assessment in childhood vasculitis. Assessment of disease activity is likely to become a major area of interest in pediatric rheumatology in the near future. After defining the classification criteria for primary systemic childhood vasculitis, the next step was to perform a validation study using the original Birmingham vasculitis activity score as well as the disease extent index to measure disease activity in childhood vasculitis. Presently, there are efforts in place to develop a pediatric vasculitis activity score. This paper reviews the current understanding about the assessment tools (i.e., clinical features, laboratory tests, radiologic assessments, etc.) widely used for evaluation of the disease activity and damage status of the children with vasculitis.

Pediatric vasculitides: a generalists approach

Vasculitis is defined as the presence of inflammation in a blood vessel that may occur as a primary process or secondary to an underlying disease. Primary vasculitides are rare in children. These are defined by both the size of vessels involved and the type of inflammatory response. Clinical features consist of multi-organ involvement on a background of constitutional features reflecting the size and location of the blood vessels involved. Whilst some vasculitides are best diagnosed clinically, many forms require sophisticated imaging and other investigations (auto antibodies) to reveal the correct diagnosis. Prompt recognition and treatment is crucial as many of the vasculitides cause significant morbidity or mortality. Treatment options range from symptomatic therapy, immunosuppresive agents, intravenous immunoglobulin (IVIG) or biologic agents and are determined by the type of vasculitis, the severity of the inflammation, and the organ systems affected. Early detection and aggressive treatment is crucial for the best outcomes in the most severe forms of childhood vasculitis.

Takayasu arteritis in children and adolescents

Takayasu arteritis is a devastating vasculitis of the aorta and its major branches. The clinical manifestations in paediatric patients are less specific than in adults: in children the disease presents with fever, arthralgias and hypertension. Intramural inflammation results in narrowing of the blood vessel lumen and therefore hypoperfusion of the parenchyma. Conventional angiography is the gold standard diagnostic procedure. Corticosteroids, cyclophosphamide, MTX and biological therapies such as TNF-α blocking agents are treatment options.

Massive hemoptysis in an 11-year-old girl with isolated pulmonary arteritis

A 10-year-old girl developed recurrent bouts of massive hemoptysis over a 9-month period. No obvious bleeding source was detected. Her pulmonary angiogram showed a pulmonary aneurysm of the second branch of the left main pulmonary artery as well as widespread irregularities of the pulmonary arteries including areas of stenosis and pruning. Elective embolization of the aneurysm did not control hemoptysis and emergency left upper lobectomy had to be performed. Histology showed large artery wall injury with acute leucocytoclastic inflammation, fibrinoid necrosis, granulomatous inflammation, and ectasia of vessel wall. This combination of abnormalities has not been described to date and represents the first case of isolated pulmonary arteritis in children prior to puberty.

Atherosclerosis in Takayasu arteritis

OBJECTIVE

Chronic inflammatory diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis are associated with accelerated atherosclerosis. We hypothesised that atherosclerosis may also be increased in Takayasu arteritis.

METHODS

The frequency of atherosclerotic plaques and the intima-media thickness (IMT) were investigated in 30 female patients with Takayasu arteritis (mean age (standard deviation), 35.4 (8.0) years), along with 45 sex-matched and age-matched patients with SLE (37.4 (6.8)) and 50 healthy controls (38.2 (5.7)). Plaques were scanned and IMT was measured at both sides of the common carotids, carotid bulb, and internal and external carotid arteries by B-mode ultrasonography. Traditional risk factors for atherosclerosis were also assessed.

RESULTS

Most of the atherosclerotic risk factors were comparable between patients with Takayasu arteritis and SLE. More atherosclerotic plaques were observed among patients with Takayasu arteritis (8/30; 27%) and those with SLE (8/45; 18%) than among the healthy controls (1/50; 2%; p = 0.005). Logistic regression analyses showed that the presence of a plaque was associated only with age in both Takayasu arteritis and SLE (p = 0.04 and 0.02, respectively). The mean overall IMT was significantly higher among patients with Takayasu arteritis (0.95+/-0.31 mm) than among the patients with SLE (0.58+/-0.10 mm) and the healthy controls (0.59+/-0.08 mm; p<0.001).

CONCLUSION

Patients with Takayasu arteritis have a high rate of atherosclerotic plaques, at least as frequent as that observed among patients with SLE.

Maladie de Takayasu

Takayasu arteritis is an inflammatory arteritis affecting large vessels, predominantly the aorta and its main branches. Thickening of the vessel wall is an early hallmark of the disease and leads to stenosis, thrombosis, and sometimes aneurysm formation. Reported incidence ranges from 1.2 to 2.6/million/year. Women aged 20 to 40 are most likely to suffer from the disease than men. Manifestations are very polymorphous, with presentations ranging from asymptomatic to neurologic catastrophes. Prognosis depends essentially on complications (retinopathy, hypertension, aneurysm, aortic insufficiency) and initial disease aggressivity. Diagnosis is based on imaging methods. Doppler ultrasound, computed tomography, and magnetic resonance imaging are fast and reliable methods for assessing vessel anatomy and luminal status. Positron emission tomography with fluorodeoxyglucose appears to be a highly sensitive and effective method for detecting disease activity, especially since standard inflammatory markers seem ineffective. Until now, corticosteroids have been the treatment of choice. If remission does not occur, methotrexate is added. Percutaneous transluminal angioplasty and sometimes vascular surgery is necessary in cases of critical ischemia or threatening aneurysm. Duration of treatment, choice of second-line treatment, and protocol for tapering medication currently depend more on experience than on evidence-based medicine. Multicenter studies are needed to guide future practice.

What is the best approach to diagnosing large-vessel vasculitis?

Temporal arteritis, including large-vessel giant cell arteritis, and Takayasu's arteritis are the two primary large-vessel vasculitides. Patients with temporal arteritis often present with headache, swollen temporal arteries, impairment of vision or symptoms of polymyalgia rheumatica. Clinical examination includes palpation of the temporal arteries and radial pulses, auscultation of the subclavian and axillary region, and fundoscopy. The presence of jaw claudication, diplopia and temporal artery abnormalities correlates with a high probability of positive histology. Duplex ultrasonography of the temporal arteries delineates a characteristic hypoechoic, oedematous wall swelling, stenoses and occlusions. It detects the same pathologies in the axillary arteries and other arteries in large-vessel giant cell arteritis. Angiography, magnetic resonance imaging, magnetic resonance angiography, electron beam computed tomography, computed tomography angiography and positron emission tomography show characteristic changes in the aorta and its primary branches in large-vessel giant cell arteritis and Takayasu's arteritis. Takayasu's arteritis often begins with diffuse symptoms such as low-grade fever, arthralgia, fatigue and weight loss. Clinical examination is important to detect bruits, pulse reduction and blood pressure differences. Profound experience exists with angiography. Other imaging methods are interesting alternatives as they are less invasive and may depict the inflammatory wall swelling.

Les aortites inflammatoires

PRINCIPLE AND OTHER CAUSES: Takayasu's arteritis, giant cell arteritis and Behçet's disease are the three main causes of inflammatory aortitis. More rarely, aortitis can be observed in Cogan's syndrome, atrophic polychondritis, sarcoidosis, ankylosing spondylitis and in rheumatoid arthritis. RISKS OF PROGRESSION: Takayasu's arteritis is distinct with the development of stenotic lesions of the aorta. With the other causes, aortitis can be complicated by ectasia or even aneurysm, with the risk of rupture. Indeed, during giant cell arteritis, patients are 17 times more likely to develop thoracic aortic aneurysm. Aortic regurgitation is a frequent complication of inflammatory aortitis. Sometimes, aortitis is only manifested by general signs such as fever or an inflammatory syndrome. SUPPLEMENTARY EXPLORATIONS: Recent advances in diagnosis and follow-up of patients with inflammatory aortitis concern the use of non-invasive imaging techniques: Doppler ultrasonography, computed tomography with injection of a contrast product and magnetic resonance imaging, which currently replace the aortography.

DIAGNOSTIC PROBLEMS

Infectious aortitis, inflammatory atheromatous aneurysm and retroperitoneal fibrosis are sometimes misleading differential diagnoses.

Imagerie des pathologies vasculaires spécifiques

The diagnosis of vascularitis should be proposed when a concentric and regular thickening of the wall of the aorta or one of its branches is observed or when there is late enhancement of the arterial wall, on sites which are usually free from atheromatous lesions and in a young patient. The radiologist must be aware of the associated clinical signs: oral and genital ulcerative lesions in the Behçet syndrome; finger necrosis in a young male smoker in Buerger disease; hip and shoulder arthropathy and headache in a 70 Year old female and Horton disease; pulseless upper limbs and inflammatory syndrome in a young adult for the Takayasu arteritis. The diagnosis of popliteal entrapment or adventitial cyst should be proposed in young patients without atheromatous lesions.

Use of imaging studies in the diagnosis of vasculitis

Imaging studies are necessary to determine disease extension and disease activity in the small-vessel vasculitides. Computed tomography (CT) and magnetic resonance imaging (MRI) increase the number of pathologic findings compared with conventional radiography. MRI delineates mucosal inflammation and granulomas in the paranasal sinuses, whereas CT provides information about osseous lesions. CT is superior to MRI for the detection of pulmonary lesions. Radiograph angiography has been the gold standard for medium- and large-vessel vasculitides for decades. Echocardiography and MRI correspond well with conventional angiography to assess cardiac involvement in Kawasaki disease. MRI, CT, and CT angiography are alternative noninvasive techniques to delineate vasculitic lesions in polyarteritis nodosa, Takayasu's arteritis, and large-vessel giant cell arteritis. Duplex ultrasonography has the greatest resolution. It delineates typical artery wall swelling in temporal arteritis and Takayasu's arteritis. Positron emission tomography can assess inflammatory activity of large arteries.

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.

Microembolus detection in patients with Takayasu's arteritis

BACKGROUND AND PURPOSE

Takayasu's arteritis (TA) is a chronic inflammatory disease of unknown etiology that can affect the aorta and its branches. The cerebral ischemia in TA can be caused by a variety of mechanisms, and the focus of this study is to detect the possible contribution of microembolus in the pathogenesis of stroke.

METHODS

Eighteen patients with TA according to the criteria for the classification of TA of the American College of Rheumatology and 100 age-matched healthy controls were studied. Both middle cerebral arteries were monitored by transcranial Doppler (TCD) ultrasound for at least 30 minutes. All patients with TA were followed up for a mean duration of 2.1 months, and recurrent strokes were registered.

RESULTS

Microembolic signals (MES) were present in 22% of the patients overall, and the intensity of the MES varied between 9 and 30 dB. Moreover, MES were found in 30% of the patients with higher erythrocyte sedimentation rate. Two (67%) of 3 patients who did not receive any treatment had MES, but only 2 (13%) of 15 patients who received immunosuppressive and anticoagulant therapy before the TCD ultrasonography monitoring had MES. During the follow-up period after MES recording, we did not observe any recurrent stroke.

CONCLUSIONS

TCD ultrasonography monitoring can be used as an additional noninvasive procedure to detect microembolus in patients with TA during the acute and chronic phase of the disease. The monitoring of MES may also help in choosing better treatment for the long-term prophylaxis of the disease from acute ischemic stroke, but further large studies are required to justify the efficacy of immunosuppressive treatment in these patients.

Pulmonary Takayasu’s Arteritis Masquerading as Acute Pulmonary Embolism

Pulmonary involvement may sometimes be the initial presentation of Takayasu's arteritis (TA). Since the signs and symptoms of pulmonary TA may be subtle and may not be easily distinguishable from other pulmonary diseases, one has to maintain a high index of suspicion. Cases of pulmonary TA mimicking chronic thromboembolism have been reported. We describe a patient with TA whose initial presentation mimicked acute pulmonary embolism. The patient presented with a 3-day history of cough and shortness of breath and had multiple bilateral perfusion defects on ventilation-perfusion scan, typical of acute pulmonary embolism. However, the constellation of clinical features, elevated erythrocyte sedimentation rate and the angiographic appearance helped us establish the correct diagnosis of pulmonary Takayasu's arteritis. At a 6-year follow-up, the patient had no worsening of pulmonary symptoms but presented with postural dizziness with angiographic evidence of carotid and innominate artery stenosis; she underwent arterial bypass grafting. In young women presenting with a clinical picture of acute pulmonary embolism without the previous history (or risk factors) of thromboembolism, pulmonary TA must be considered in the differential diagnosis.

Follow-up electron beam CT for the management of early phase Takayasu arteritis

PURPOSE

The purpose of this work was to assess typical findings of Takayasu arteritis on serial CT examinations following therapy.

METHOD

Serial CT studies were performed on 16 patients with early phase Takayasu arteritis. Mural or luminal changes of the aorta on successive CT scans were compared with clinical data.

RESULTS

Vascular lesions progressed during follow-up in 6 of 16 patients. In one patient, progression of lesions was symptomatic. In the other five of six patients with worsening lesions, vascular progression occurred without new clinical symptoms and was first identified on CT scans. One of these five had dilatation of the ascending aorta and required aortic repair. Four others had progression of stenotic vascular lesions leading to changes in medical treatment only or in combination with either surgery or angioplasty. For two of them, CT examinations showed decreased mural lesions after changes in medical treatment.

CONCLUSION

CT examinations performed in treated patients with Takayasu arteritis demonstrate either regression, stabilization, or progression of vascular lesions. Serial CT examinations may thus be useful for evaluating response to treatment.

Diagnosis of vasculitis

Vasculitis is a process that results from the inflammation of blood vessels and can occur de novo or secondary to a variety of diseases or drugs. Clinical presentation depends on the size and distribution of vessels involved. Anti-neutrophil cytoplasmic antibodies (ANCA) have been shown to have variable sensitivity in making the diagnosis of specific vasculitic syndromes, therefore histological confirmation may be necessary. Angiography is a useful tool in evaluating disease of large and medium-sized vessels that are inaccessible or potentially dangerous to biopsy. New imaging modalities are becoming more useful in diagnosing vessel wall changes, particularly in large-vessel vasculitides. In clinical practice it is not always possible to classify or apply a specific label to a patient with vasculitis, but for appropriate patient management it is important to define the extent and severity of disease and to exclude underlying secondary causes.