Use of ultrasonography and positron emission tomography in the diagnosis and assessment of large-vessel vasculitis

Tomographic ultrasound for three-dimensional visualization of temporal arteries

OBJECTIVE

Conventional two-dimensional ultrasound has been assessed for the non-invasive diagnosis of giant cell arteritis (GCA), but the results are operator dependent, resulting in low sensitivity. Tomographic three-dimensional (3D) ultrasound is a novel technique that enables the objective documentation of vessel geometry. Here, for the first time, its utility is assessed for visualizing temporal arteries.

METHOD

The temporal artery of 14 healthy subjects and three subjects with suspected GCA was examined using tomographic 3D ultrasound.

RESULTS

This technique enabled 3D mapping of the architecture of the temporal artery. The inner and outer vessel diameters showed considerable interindividual variability. However, calculation of the vessel wall fraction revealed the combination of vessel wall thickening and lumen narrowing, which may be indicative of GCA.

CONCLUSIONS

This proof-of-concept study indicates that tomographic 3D ultrasound can be used for objective mapping of the temporal artery. The technique must be evaluated regarding its diagnostic sensitivity in GCA before it can be introduced in clinical practice.

Musculoskeletal ultrasonography in rheumatic diseases

Ultrasonography is an imaging technique based on sound waves used for the evaluation of soft tissues. Sound waves have been used for a long time in nonmedical fields, including military defense systems, radar systems, and detection of icebergs. Technological advances resulted in new techniques becoming available for medical imaging, including ultrasonography, magnetic resonance imaging, and computed tomography. Nowadays, the use of imaging has become a gold standard protocol in the diagnosis of many diseases, and recently developed diagnosis and therapy options provide more efficient treatment of rheumatic diseases. Thus, it has become possible to prevent structural damage and disability in patients with rheumatic disease. Musculoskeletal ultrasonography is becoming a preferred imaging technique for rheumatic diseases, as it has many advantages. Among its advantages are being inexpensive, being radiation-free, having a dynamic image capacity, helping to detect disease activity, and helping with early detection and diagnosis of structural damage. This review summarizes the use of ultrasonography in rheumatic diseases.

Diffusion-weighted Whole-body Imaging with Background Body Signal Suppression (DWIBS) as a Novel Imaging Modality for Disease Activity Assessment in Takayasu's Arteritis

A 26-year-old woman with Takayasu's arteritis (TAK) experienced back and neck pain during tocilizumab (TCZ) treatment. The levels of C-reactive protein were normal, and ultrasonography revealed no significant changes. Diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) showed signal enhancement in the walls of several arteries. Contrast computed tomography showed arterial inflammation in the same lesion. After increasing the dose of prednisolone and TCZ, all signal enhancements decreased and continued to decrease, as observed on days 76 and 132. Thus, DWIBS may be a novel imaging modality for assessing the disease activity of TAK, particularly during follow-up.

Large-vessel giant cell arteritis: diagnosis, monitoring and management

GCA is a chronic, idiopathic, granulomatous vasculitis of medium and large arteries. It comprises overlapping phenotypes including classic cranial arteritis and extra-cranial GCA, otherwise termed large-vessel GCA (LV-GCA). Vascular complications associated with LV-GCA may be due, in part, to delayed diagnosis, highlighting the importance of early identification and prompt initiation of effective therapy. Advancements in imaging techniques, including magnetic resonance angiography, CT angiography, PET and colour duplex ultrasonography, have led to improvements in the diagnosis of LV-GCA; however, the role imaging modalities play in the assessment of disease activity and long-term outcomes remains unclear. Glucocorticoids are the mainstay of therapy in LV-GCA, but their prolonged use is associated with multiple, sometimes serious, adverse effects. Recent data suggest that biologic therapies, such as tocilizumab, may be effective and safe steroid-sparing options for patients with GCA. However, data specifically evaluating the management of LV-GCA are limited.

Spectrum of Aortic Disease in the Giant Cell Arteritis Population

We report the spectrum of aortic involvement in patients with giant cell arteritis (GCA) following review of medical records of 4,006 patients including those with imaging studies. A total of 1,450 patients (36%) had a confirmed diagnosis of GCA. Of these, 974 had aortic imaging. Of the 974 patients with imaging, 435 (45%) had an identified aortopathy. The most common aortopathy was aneurysm/dilation (69%). Overall, an annual aneurysmal growth rate of 1.5 mm/y was calculated. In patients with aneurysm/dilation, aortic dissection occurred in 18 patients (6%), and these patients had a significantly higher aneurysmal growth rate compared with those without dissection (4.5 vs 1.4 mm/y, p = 0.005). The median size of the aorta at the time of dissection was 51 mm, with 7 (39%) occurring with a maximal aortic aneurysm/dilation <50 mm. In conclusion, our findings indicate higher aneurysmal growth rate in GCA compared with that reported for degenerative aortic disease. Moreover, patients who develop dissection had a significantly higher growth rate than those without dissection with over a third of these patients suffering dissection at a caliber <50 mm.

Development of a Core Set of Outcome Measures for Large-vessel Vasculitis: Report from OMERACT 2016

OBJECTIVE

Among the challenges in conducting clinical trials in large-vessel vasculitis (LVV), including both giant cell arteritis (GCA) and Takayasu arteritis (TA), is the lack of standardized and meaningful outcome measures. The Outcome Measures in Rheumatology (OMERACT) Vasculitis Working Group initiated an international effort to develop and validate data-driven outcome tools for clinical investigation in LVV.

METHODS

An international Delphi exercise was completed to gather opinions from clinical experts on LVV-related domains considered important to measure in trials. Patient interviews and focus groups were completed to identify outcomes of importance to patients. The results of these activities were presented and discussed in a "Virtual Special Interest Group" using telephone- and Internet-based conferences, discussions through electronic mail, and an in-person session at the 2016 OMERACT meeting. A preliminary core set of domains common for all forms of LVV with disease-specific elements was proposed.

RESULTS

The majority of experts agree with using common outcome measures for GCA and TA, with the option of supplementation with disease-specific items. Following interviews and focus groups, pain, fatigue, and emotional effect emerged as health-related quality of life domains important to patients. Current disease assessment tools, including the Birmingham Vasculitis Activity Score, were found to be inadequate to assess disease activity in GCA and standardized assessment of imaging tests were felt crucial to study LVV, especially TA.

CONCLUSION

Initial data from a clinician Delphi exercise and structured patient interviews have provided themes toward an OMERACT-endorsed core set of domains and outcome measures.

Head and neck giant cell arteritis: an autoimmune disease with many faces

CONCLUSION

A high rate of infrequent presentations of giant cell arteritis were seen in the ENT department and should be anticipated as a differential diagnosis in every older patient with odynophagia with high CRP values without cause in thorough ENT examination.

OBJECTIVE

To describe the clinical manifestation of head and neck giant cell arteritis and to derive a diagnostic pathway covering atypical cases.

METHOD

Single-center, retrospective analysis of cases with GCA in the head and neck region (HN-GCA) (2002-2012) to describe the clinical presentation and to derive a diagnostic pathway covering manifestations presenting to an ENT department.

RESULTS

Sixty-five patients were newly diagnosed with HN-GCA in the department of otolaryngology, ophthalmology and neurology. The most frequent symptoms were loss of vision (83%) and new onset headache (63%). Eight patients (12%) presented with infrequent manifestations, predominantly in the department of otorhinolaryngology. The most common atypical presentation (50%) was odynophagia in conjunction with high CRP values misleading to an infectious cause and delaying diagnosis. A diagnostic pathway for GCA was derived based on the ACR classification criteria and the clinical findings.

Magnetic resonance imaging in the diagnosis and follow-up of giant cell arteritis: case report and review of literature

A female patient with giant cell vasculitis of the abdominal aorta and its branches and strongly suspected of having extrapulmonary tuberculosis is presented. The diagnoses were based on the clinical picture, laboratory findings, and magnetic resonance imaging (MRI) findings. MRI is highly useful in cases where echosonography and/or vascular biopsy for histopathological analyses are not possible. A combination of giant cell vasculitis and extrapulmonary tuberculosis is extremely rare, and therefore, choosing the right treatment presents a considerable challenge. MRI performed after 6-month antituberculous therapy and 1-year glucocorticoid plus methotrexate therapy showed normal wall of the aorta and its branches, which was consistent with clinical and laboratory remission. Patients with large vessel vasculitis require regular follow-up by MRI.

Inflammatory diseases of the aorta: Part 2: Infectious aortitis

Infectious aortitis is a rare but life-threatening disease. Due to impending local and systemic complications, prompt diagnosis and initiation of effective causal treatment are essential for patient survival. Differentiating infectious aortitis from other aortic diseases, in particular non-infectious aortitis, is of great importance. This article discusses the various causes, diagnostic tools, and therapeutic strategies for infectious aortitis.

Cardiac involvement in antiphospholipid syndrome: The diagnostic role of noninvasive cardiac imaging

OBJECTIVES

The antiphospholipid syndrome (APS) is an autoimmune disorder of acquired hypercoagulability characterized by vascular thrombosis, increased pregnancy morbidity, and elevated levels of antiphospholipid antibodies. Cardiac involvement in APS may be presented as heart valve disease affecting approximately a third of patients or less frequently as intracardial thombosis, pulmonary hypertension, right or left ventricular dysfunction, micro-vascular thrombosis, coronary artery, or micro-vascular disease with overt or silent clinical presentation.

METHODS

Noninvasive cardiovascular imaging plays a crucial role in the evaluation of heart involvement in APS. Transthoracic or transoesophageal echocardiography enable early, accurate diagnosis and severity assessment of HVD as well as of ventricular dysfunction and pulmonary hypertension. Studies by echocardiography and nuclear imaging have detected abnormalities in myocardial perfusion in approximately 30% of primary APS. CT scan is the technique of choice for the assessment of pulmonary embolism and can effectively detect intracardiac thrombi. Myocardial perfusion defects have been detected by 13N-ammonia PET in 40% of APS. Cardiovascular magnetic resonance (CMR) has identified an unexpectedly high prevalence of occult myocardial scarring and endomyocardial fibrosis in APS, and is the technique of choice, if quantification of heart valve disease and stress myocardial perfusion-fibrosis is needed.

RESULTS

Noninvasive, nonradiating imaging techniques, such as echocardiography and CMR are superior to CT or nuclear techniques and are of great value for the diagnosis and follow-up of both clinically overt and silent cardiac disease in APS.

CONCLUSIONS

The high incidence of cardiac involvement in APS demands early diagnosis/treatment and multimodality cardiovascular imaging is of great importance.

Imaging in systemic vasculitis

PURPOSE OF REVIEW

Imaging is becoming a relevant tool for the assessment of patients with systemic vasculitis. This review focuses on recently generated data with potential clinical impact in the diagnosis, evaluation of disease extent and management of systemic vasculitis.

RECENT FINDINGS

Temporal artery examination by color duplex ultrasonography (CDUS) is a valuable approach to the diagnosis of giant-cell arteritis. Evaluation of additional arteries may increase its diagnostic performance. However, CDUS-specific findings may not be detected in arteries with early inflammation and CDUS-guidance of temporal artery biopsy does not seem to significantly increase its diagnostic yield. Large-vessel involvement detected by computed tomography angiography occurs in two out of three of patients with giant-cell arteritis at diagnosis. Furthermore, significant ascending aortic dilatation can be observed in one out of three of patients after long-term follow-up. Objective cut-offs for detecting large-vessel inflammation by positron emission tomography (PET) are trying to be established through prospective studies. PET may also contribute to the assessment of disease extent in patients with ANCA-associated vasculitis or Behçet's disease.

SUMMARY

Data generated by existing and emerging imaging techniques are expected to have a major impact in the diagnosis, appraisal of disease extent, evaluation of disease activity and response to treatment in patients with systemic vasculitis.

Temporal arteritis: improving patient evaluation with a new protocol

CONTEXT

The process of diagnosing temporal arteritis remains controversial. Although temporal artery biopsy has long been the standard tool of evaluation, its poor sensitivity has prompted investigation of other methods to aid in diagnosis. Improved clinical evaluation and various imaging techniques have been suggested as ways to establish the diagnosis through noninvasive means and to improve biopsy yield.

OBJECTIVE

To retrospectively report and evaluate the process and experience of the Kaiser Permanente Northwest Region in implementing a new protocol that includes an enhanced clinical evaluation as well as the incorporation of color duplex ultrasonography in addition to biopsy when appropriate for temporal arteritis evaluation.

RESULTS

A 38% reduction in the number of temporal artery biopsies performed was achieved through the new protocol, which was created by a multidisciplinary process, including stakeholders from all departments involved. The percentage of abnormal biopsy results rose from 8.5% at baseline to 24%. No cases of the disease were missed after careful evaluation of clinical and medical-legal records.

CONCLUSIONS

Adding specialist clinical evaluation and color duplex ultrasonography to the standard diagnostic workup for temporal arteritis creates a rapid, noninvasive, resource-sensible means to diagnose giant cell arteritis, to improve temporal artery biopsy yield, and to decrease the total number of biopsies done. The diagnosis can be made in some cases by clinical evaluation and color duplex ultrasonography alone, thereby saving the patient an unnecessary surgical procedure. Protocols such as this can be implemented by multidisciplinary cooperation in a patient-centered, integrated system.

Nonarteriosclerotic vascular disease

Thromboangiitis obliterans, or Buerger disease, is a chronic nonatherosclerotic endarteritis manifesting as inflammation and thrombosis of distal extremity small and medium-sized arteries resulting in relapsing episodes of distal extremity ischemia. Takayasu arteritis is a rare syndrome characterized by inflammation of the aortic arch, pulmonary, coronary, and cerebral vessels, presenting with cerebrovascular symptoms, myocardial ischemia, or upper extremity claudication in young, often female, patients. Kawasaki disease is a small- and medium-vessel acute systemic vasculitis of young children, with morbidity and mortality stemming from coronary artery aneurysms. Microscopic polyangiitis, Churg-Strauss syndrome, and Wegener granulomatosis are systemic small-vessel vasculitides, affecting arterioles, capillary beds and venules, and each presenting with variable effects on the pulmonary, renal and gastrointestinal systems.

The use of temporal artery ultrasound in the diagnosis of giant cell arteritis in routine practice

AIM

The exact diagnostic role of temporal artery ultrasound (TAU) remains unclear. The aim of this study was to determine the sensitivity and specificity of a positive halo sign in patients undergoing TAU in a clinical setting, and to perform a review of existing evidence.

METHOD

Patients who had undergone TAU at a single centre in Australia were included in the study. The presence or absence of a halo sign and whether it was unilateral or bilateral was determined retrospectively from radiology reports. Pathology results were used to determine which patients underwent a temporal artery biopsy and if the biopsy was positive or negative. A case note review was performed to determine presenting clinical features and if a clinical diagnosis of giant cell arteritis was made. The sensitivity, specificity and likelihood ratios of TAU compared to both biopsy and clinical diagnosis were calculated.

RESULTS

Fifty patients were identified as having had a TAU (28% male, mean age 69). When compared to biopsy-proven cases, the sensitivity of a halo sign was 40%, specificity 81%, positive likelihood ratio 2.1 and negative likelihood ratio 0.7. When compared to clinical diagnosis, the sensitivity was 42%, specificity 94%, positive likelihood ratio 7.1 and negative likelihood 0.6.

CONCLUSIONS

Sensitivity and specificity results were comparable to the literature. A halo sign may preclude the need for biopsy in cases of high clinical suspicion and contraindications to surgery. Biopsy remains necessary in most cases, irrespective of whether a halo sign is present.

Takayasu arteritis: diagnosis, treatment and prognosis

Takayasu arteritis (TA) is a chronic nonspecific granulomatous vasculitis affecting aorta and its main branches, coronary and pulmonary arteries. TA often occurs in young women and has a characteristic heterogeneity depending on ethnicity and geographical location. Although the pathogenesis of TA remains unclear, the interaction of many factors, such as autoimmunity, inflammation, genetic and environmental factors and so on, is involved in the occurrence and development of TA. Angiography, which is recognized as the gold standard in evaluating vascular lesions in TA, combined with computer tomography angiography (CTA), magnetic resonance angiography (MRA), ultrasonography, (18)Fluorodeoxyglucose positron emission tomography ((18)F-FDG-PET) could not only provide important information for early diagnosis but also detect disease activity, and thus further guide the treatment in TA. In addition, beside the commonly used corticosteroids, immunosuppressive agents, percutaneous transluminal angioplasty (PTA) and surgical revascularization, anti-tumor necrosis factor (TNF) agent has been more widely used in refractory cases of TA. The objective of this review is to systemically describe the pathogenesis, clinical characteristics, diagnosis, treatment and prognosis of TA.

Role of diagnostic ultrasound in the assessment of musculoskeletal diseases

The wide availability and recent improvement in technology coupled with portability, low cost and safety makes ultrasound the first choice imaging investigation for the evaluation of musculoskeletal diseases. Diagnostic use of ultrasound findings is greatly enhanced by knowledge of the clinical presentation. Conversely, ultrasound skills with its prerequisite anatomical knowledge make the clinical diagnosis more precise and reduce uncertainty in the choice of therapy. Therefore, it is essential for rheumatologists to acquire ultrasonography skills in order to improve patient care. Ultrasound examination provides an excellent opportunity for patient education and to explain the rationale for therapy. This review summarizes the indications for musculoskeletal ultrasound and describes its role in diagnosis, monitoring and prognosis.

Takayasu's arteritis presenting with temporary loss of vision in a 23-year-old woman with beta thalassemia trait: a case report

INTRODUCTION

The simultaneous presence of Takayasu's arteritis and beta thalassemia trait is a rare combination. To the best of our knowledge, this is the first case report on Takayasu's arteritis and beta thalassemia presenting together.

CASE PRESENTATION

This is a case report of a 23-year-old Asian woman of Pakistani descent who presented with a headache, blurred vision and dizziness.

CONCLUSION

The correct diagnosis of our patient was based on clinical suspicion, appropriate imaging studies, and deliberation of the differential diagnosis. The management of our patient depended on the correct diagnosis of both the diseases.

[Giant cell arteritis-related upper/lower limb vasculitis]

Upper/lower limb vasculitis has been considered an uncommon manifestation of giant cell arteritis, occurring in 3 to 16% of patients. Upper/lower limb vasculitis is still associated with significant morbidity, leading to limb/toe amputation in 5.6 to 15.8% of patients. Yearly clinical vascular examination should be performed systematically to screen upper/lower limb vasculitis at an early stage in patients with giant cell arteritis. Duplex ultrasound has proved to be a reliable non-invasive imaging method for detecting arterial stenoses of the upper/lower limbs in patients with giant cell arteritis. Patients with giant cell arteritis-related upper/lower limb vasculitis should undergo routine investigations to detect underlying aortic complications, concomitant aortic localizations being encountered in more than 50% of cases. Prednisone is the first-line therapy at an initial dose of 0.7-1 mg/kg daily. Prevention of platelet aggregation with low-dose aspirin is potentially effective in preventing ischemic complications of GCA. The indication of surgical therapy should be based on the severity of giant cell arteritis-related upper/lower limb clinical symptoms to avoid unnecessary morbidity in the course of interventional therapy.

Long-term follow-up of upper and lower extremity vasculitis related to giant cell arteritis: a series of 36 patients

We conducted this retrospective study to determine the prevalence of giant cell arteritis (GCA) in patients exhibiting nonatherosclerotic upper and/or lower extremity arterial involvement and to evaluate the clinical features and long-term outcome of those patients.From January 1997 to March 2008, 36 consecutive patients in the Department of Internal Medicine at the University of Rouen medical center received a diagnosis of symptomatic upper/lower extremity vasculitis related to GCA. In the 36 patients, upper/lower extremity vasculitis preceded the initial GCA diagnosis in 7 patients (19.4%), it was identified in association with GCA in 13 patients (36.1%), and it developed after the onset of GCA in the remaining 16 patients (44.4%). GCA clinical manifestations were severe resulting in ischemic complications of the extremities in 10 patients (27.8%). GCA-related large-vessel involvement was located in the upper extremity alone in 21 patients (58.3%), the lower extremity alone in 7 patients (19.4%), and both the upper and lower extremities in 8 patients (22.2%).Arterial involvement in GCA patients with upper extremity vasculitis was distributed in the subclavian (55.6%), axillary (47.2%), and brachial (22.2%) arteries. In patients with lower extremity vasculitis, involvement included the internal iliac artery (11.1%), common femoral artery (13.9%), superficial femoral artery (33.3%), deep femoral artery (5.6%), and popliteal and anterior tibial arteries (5.6%). Aortic localizations were common in GCA patients with upper/lower extremity vasculitis (68.9% of cases).All patients were given steroid therapy at a median daily dose of 1 mg/kg initially. Reconstructive study was performed in 10 patients (27.8%): venous bypass graft (n = 6), angioplasty (n = 1), thromboendarteriectomy (n = 2), or thrombectomy (n = 1); 2 other patients with extremity ischemia underwent amputation. The median observation time was 32 months; the outcome of upper/lower extremity vasculitis was disappearance of clinical symptoms (44.4%), improvement of clinical manifestations (44.4%), and deterioration of clinical manifestations (11.1%). At last follow-up, the median daily dose of prednisone was 6 mg. Steroid therapy could be discontinued in 12 patients (33.3%).We found that upper/lower extremity vasculitis is not uncommon in patients with GCA, and may be present in the early acute phase of GCA. Nevertheless, because upper/lower extremity vasculitis occurs during the course of GCA, yearly clinical vascular examinations may be adequate to screen for upper/lower extremity vasculitis at an early stage in GCA patients. Early diagnosis of GCA-related upper/lower extremity vasculitis is crucial, and can result in decreased severe ischemic complications. Because aortic localizations were common, GCA patients with upper/lower extremity vasculitis should undergo routine investigations for underlying life-threatening aortic complications (aortic ectasia/aneurysm). We also suggest that patients exhibiting aortic complications should undergo routine clinical vascular examination to detect upper/lower extremity vasculitis.

Is fluorine 18 fluorodeoxyglucose positron emission tomography scanning a suitable diagnostic test for histologically active large-vessel vasculitis?

Recent publications have highlighted the use of fluorine 18 fluorodeoxyglucose (F-FDG) positron emission tomography (PET) as a moderately sensitive, noninvasive diagnostic test for medium- and large-vessel vasculitis. We report the atypical case of a patient with biopsy-proven granulomatous vasculitis of the aorta in addition to a non-small cell lung cancer, whose whole-body F-FDG PET/computed tomography scan demonstrated metabolic activity within the lung malignancy but was metabolically inactive in the aorta. We submit that F-FDG PET may not be an accurate diagnostic test for histologically active large-vessel vasculitis and should be used with caution.

Imaging of pulmonary vasculitis

The presence of pulmonary vasculitis can be suggested by a clinical presentation that includes diffuse pulmonary hemorrhage, acute glomerulonephritis, chronic refractory sinusitis or rhinorrhea, imaging findings of nodules or cavities, mononeuritis multiplex, multisystemic disease, and palpable purpura. Serologic tests, including the use of cytoplasmic antineutrophil cytoplasmic antibody (ANCA) and perinuclear ANCA, are performed for the differential diagnosis of the diseases. A positive cytoplasmic ANCA test result is specific enough to make a diagnosis of ANCA-associated granulomatous vasculitis if the clinical features are typical. Perinuclear ANCA positivity raises the possibility of Churg-Strauss syndrome or microscopic polyangiitis. Imaging findings of pulmonary vasculitis are diverse and often poorly specific. The use of a pattern-based approach to the imaging findings may help narrow the differential diagnosis of various pulmonary vasculitides. Integration of clinical, laboratory, and imaging findings is mandatory for making a reasonably specific diagnosis.

[Vasculitis assessment with [18F]FDG positron emission tomography]

[18F]fluorodeoxyglucose positron emission tomography (PET) is a noninvasive metabolic imaging modality that is well-suited to the assessment of activity and extent of large vessel vasculitis. PET imaging has demonstrated its usefulness in diagnosing giant cell arteritis (notably in its silent form), Takayasu's arteritis, and unclassified aortitis. PET imaging could be more effective than magnetic resonance imaging in detecting the earliest stages of vascular wall inflammation. The visual grading of vascular [18F]FDG uptake makes it possible to discriminate arteritis from active atherosclerosis, providing therefore high specificity. High sensitivity can also be achieved provided scanning is performed during active inflammatory phase, preferably before starting corticosteroid treatment. Prospective studies are needed to determine the exact value of PET imaging in assessing other vasculitis subsets, infectious aortitis, and large vessel vasculitis outcome and response to immunosuppressive treatment.

The diagnostic value of ultrasonography-derived edema of the temporal artery wall in giant cell arteritis: a second meta-analysis

BACKGROUND

Ultrasonography of temporal arteries is not commonly used in the approach of patients with suspected giant cell arteritis (GCA) in clinical practice. A meta-analysis of primary studies available through April 2004 concluded that ultrasonography could indeed be helpful in diagnosing GCA. We specifically re-examined the diagnostic value of the ultrasonography-derived halo sign, a dark hypoechoic circumferential thickening around the artery lumen, indicating vasculitic wall edema, in GCA.

METHODS

Original, prospective studies in patients with suspected GCA that examined ultrasonography findings of temporal arteries using the ACR 1990 classification criteria for GCA as reference standard, published through 2009, were identified. Only eight studies involving 575 patients, 204 of whom received the final diagnosis of GCA, fulfilled technical quality criteria for ultrasound. Weighted sensitivity and specificity estimates of the halo sign were assessed, their possible heterogeneity was investigated and pooled diagnostic odds ratio was determined.

RESULTS

Unilateral halo sign achieved an overall sensitivity of 68% (95% CI, 0.61-0.74) and specificity of 91% (95% CI, 0.88-0.94) for GCA. The values of inconsistency coefficient (I2) of both sensitivity and specificity of the halo sign, showed significant heterogeneity concerning the results between studies. Pooled diagnostic odds ratio, expressing how much greater the odds of having GCA are for patients with halo sign than for those without, was 34 (95% CI, 8.21-138.23). Diagnostic odds ratio was further increased to 65 (95% CI, 17.86-236.82) when bilateral halo signs were present (sensitivity/specificity of 43% and 100%, respectively). In both cases, it was found that DOR was constant across studies.

CONCLUSION

Temporal artery edema demonstrated as halo sign should be always looked for in ultrasonography when GCA is suspected. Providing that currently accepted technical quality criteria are fulfilled, halo sign's sensitivity and specificity are comparable to those of autoantibodies used as diagnostic tests in rheumatology. Validation of revised GCA classification criteria which will include the halo sign may be warranted.

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.

Takayasu arteritis in children

Takayasu arteritis (TA) is a large vessel vasculitis that usually affects young female patients during the second and third decades of life, but has been reported in children as young as 24 months of age. Aim of this report was to describe four children (two girls) with TA, as well as summarizing main published studies. The mean age at presentation of our cases was 11 years (range 8-15). Three patients were Caucasians and one Asian. Arterial hypertension was the commonest mode of presentation followed by systemic symptoms. Other related symptoms were due to ischemia and consisted of abdomen, chest, and limb pain. An abdominal bruit was noted in only one patient. Inflammation markers were always abnormal. Angiography was performed in all cases; left subclavian artery and common carotid artery were more frequently involved. Renal artery stenosis was observed in two patients. One boy was diagnosed as having an associated immune deficiency (Wiskott-Aldrich syndrome). Treatment modalities included prednisone (n = 4), methotrexate (n = 3), and mycophenolate mofetil (MMF) (n = 1). Surgery was required in two patients. Follow-up ranged from 3 to 10 years since diagnosis. In three cases antihypertensive drugs and methotrexate were stopped, and prednisone was reduced to 7.5 mg/day.

Aortic involvement in recent-onset giant cell (temporal) arteritis: a case-control prospective study using helical aortic computed tomodensitometric scan

OBJECTIVE

The prevalence of the involvement of large vessels in giant cell arteritis (GCA) is 3-13%. Aortitis is the most serious complication of GCA. Computed tomodensitometric (CT) scan allows analysis of both the aortic wall and endoluminal part of the aorta. Therefore, we conducted a study using CT scan to analyze aortic abnormalities in patients with recent-onset GCA.

METHODS

This prospective controlled study compared patients with biopsy-proven GCA with a matched control group based on sex, age, and cardiovascular risk factors. During the 4-week period following diagnosis of GCA, patients underwent an aortic CT scan. The aortic imaging results were blindly compared between both groups.

RESULTS

From January 5, 1998 to January 11, 1999, 22 patients and 22 controls were screened by CT scan for aortic involvement. Thickening of the aortic wall was more frequent among patients than controls (45.4% versus 13.6%; P = 0.02). Aortic thickening (mean 3.3 mm) was located on the ascending part of the thoracic aorta in 22.7% of the patients, with no evidence of thickening in the controls (P = 0.05). Thickening of the abdominal aortic wall was noted in 27.3% of the patients and none of the controls (P = 0.02).

CONCLUSION

This study suggests that inflammatory aortic thickening, detected by CT scan, occurs frequently at the time of diagnosis of GCA, and that this condition predominantly occurs on the ascending part of the aorta.

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.

Development of aortic aneurysm/dilatation during the followup of patients with giant cell arteritis: a cross-sectional screening of fifty-four prospectively followed patients

OBJECTIVE

Giant cell arteritis (GCA) may involve the aorta. Retrospective studies have demonstrated a higher prevalence of aortic aneurysm among patients with GCA compared with the general population. We investigated the prevalence of aortic aneurysm in a cohort of patients with biopsy-proven GCA using a defined protocol and assessed whether persisting low-grade disease activity is associated with higher risk of developing aortic aneurysm.

METHODS

Fifty-four patients with GCA (14 men and 40 women) were cross-sectionally evaluated after a median followup of 5.4 years (range 4.0-10.5 years). The screening protocol included a chest radiograph, abdominal ultrasonography scan, and computed tomography scan when aortic aneurysm was suspected or changes with respect to the baseline chest radiograph were observed. Clinical and laboratory data, corticosteroid requirements, and relapses were prospectively recorded.

RESULTS

Twelve patients (22.2%) had significant aortic structural damage (aneurysm/dilatation), 5 of them candidates for surgical repair. Aortic aneurysm/dilatation was more frequent among men (50%) than women (12.5%; relative risk 3.5, 95% confidence interval 1.53-8.01, P = 0.007). At the time of screening, patients with aneurysm/dilatation had lower serum acute-phase reactants, lower relapse rate, and needed shorter periods to withdraw prednisone than patients without aortic structural damage.

CONCLUSION

There is a substantial risk of developing aortic aneurysm/dilatation among patients with GCA. Our data do not support that aneurysm formation mainly results from persistent detectable disease activity. Additional factors including characteristics of the initial injury or the target tissue may also determine susceptibility to aortic aneurysm/dilatation.