Evaluation of Disease Activity Using F-18 FDG PET-CT in Patients With Takayasu Arteritis

Design and Protocol for Beijing Hospital Takayasu Arteritis (BeTA) Biobank

BACKGROUND

Although hundreds of studies have been conducted, our understanding of the pathogenesis, indications for surgical intervention, and disease markers of Takayasu arteritis (TAK) are still limited. Collection of biological specimens, clinical data and imaging data will facilitate translational research and clinical studies. In this study, we aim to introduce the design and protocol for the Beijing Hospital Takayasu Arteritis (BeTA) Biobank.

METHODS

Based in the Department of Vascular Surgery of Beijing Hospital and Beijing Hospital Clinical Biological Sample Management Center, the BeTA Biobank is composed of clinical data and sample data from patients with TAK requiring surgical treatment. All clinical data of participants are collected, including demographic characteristics, laboratory tests, imaging results, operation information, perioperative complications, follow-up data, etc. Both blood samples including plasma, serum and cells, and vascular tissues or perivascular adipose tissue are collected and stored. These samples will promote the establishment of a multiomic database for TAK and help to identify disease markers and to explore potential targets for specific future drugs for TAK.

Derivation and Validation of a New Disease Activity Assessment Tool With Higher Accuracy for Takayasu Arteritis

Objective

To develop a new disease activity assessment tool with high accuracy for Takayasu arteritis.

Methods

Individual items from National Institute of Health (NIH) criteria and the Indian Takayasu Clinical Activity Score (ITAS2010) were tested as candidate variables to develop a new disease activity assessment tool in a derivation cohort (N = 100). Physician global assessment on disease activity was used as the gold standard. Multivariable logistic regression models were constructed and the model with the highest accuracy was identified. A formula assessing disease activity was generated using simplified β coefficients (rounded to decimal place). Diagnostic performance was evaluated through estimating the area under the curve (AUC). The new assessment tool was subsequently validated in a validation cohort (N = 46).

Results

The multivariable model yielding the highest accuracy consisted of a high erythrocyte sedimentation rate (ESR), NIH criteria 1 and 4, and carotidynia. Using simplified β coefficients, the following disease activity assessment tool was developed: high ESR (3 points), NIH criterion 1 (2 points), NIH criterion 4 (4 points), and carotidynia (3 points) (total score ≥5, active; total score <5, inactive). The new disease activity assessment tool had a higher AUC (89.37) for discriminating active and inactive diseases than NIH criteria (AUC 77.96), ITAS2010 (AUC 66.12), ITAS-ESR (AUC 75.58), and ITAS-C-reactive protein (AUC 71.34). The AUC (85.23) of the new assessment tool was similar in the validation cohort.

Conclusion

A new disease activity assessment tool that consists of high ESR, NIH criteria 1 and 4, and carotidynia had higher accuracy in discriminating active and inactive disease than currently used clinical assessment tools.

Vascular Uptake on 18F-FDG PET/CT During the Clinically Inactive State of Takayasu Arteritis Is Associated with a Higher Risk of Relapse

PURPOSE

To evaluate whether vascular uptake on ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) during the clinically inactive state of Takayasu arteritis (TAK) is associated with disease relapse.

MATERIALS AND METHODS

Patients with TAK who underwent ¹⁸F-FDG PET/CT during the clinically inactive state of the disease between 2006 and 2019 were included. Clinically inactive disease was defined as a status not fulfilling the National Institutes of Health (NIH) criteria for active disease in TAK. Relapse was defined as recurrence of clinically active disease after a clinically inactive period, requiring change in the treatment regimen. Vascular uptake on ¹⁸F-FDG PET/CT was assessed using target/background ratio (TBR), calculated as arterial maximum standardized uptake value (SUV)/mean SUV in venous blood pool. Multivariable Cox regression analysis was performed to identify factors associated with relapse.

RESULTS

A total of 33 patients with clinically inactive TAK were included. During a median observation period of 4.5 (0.9-8.1) years, relapse occurred in 9 (27.3%) patients at median 1.3 (0.7-6.9) years. Notably, TBR [1.5 (1.3-1.8) vs. 1.3 (1.1-1.4), p=0.044] was significantly higher in patients who relapsed than in those who did not. On multivariable Cox regression analysis, the presence of NIH criterion 2 [adjusted hazard ratio (HR): 7.044 (1.424-34.855), p=0.017] and TBR [adjusted HR: 11.533 (1.053-126.282), p=0.045] were significantly associated with an increased risk of relapse.

CONCLUSION

Vascular uptake on ¹⁸F-FDG PET/CT and the presence of NIH criterion 2 are associated with future relapse in patients with clinically inactive TAK.

Value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in the evaluation of pulmonary artery activity in patients with Takayasu's arteritis

AIMS

To explore the value of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in the detection of active pulmonary artery (PA) lesions in patients with Takayasu's arteritis (TA).

METHODS AND RESULTS

Consecutive TA patients with PA involvement were prospectively recruited. Clinical activity was assessed according to the National Institutes of Health (NIH) criteria. CT pulmonary angiography (CTPA) or magnetic resonance pulmonary angiography was performed for evaluation of vascular structural characteristics, and mural thickening was considered as radiologically active. A vascular segment with 18F-FDG uptake ≥ liver was considered as PET-active. A total of 38 18F-FDG PET/CT scans were performed in 29 patients. In terms of disease activity, the sensitivity of 18F-FDG PET/CT did not significantly differ from radiological imaging (71.4% vs. 92.9%, P = 0.250), but 18F-FDG PET/CT had higher specificity (91.7% vs. 37.5%, P = 0.001) and accuracy (84.2% vs. 57.9%, P = 0.022). Although the majority of PET-active PA segments (54.9%) showed mural thickening, 14 PA segments with normal structure were also PET-active. 18F-FDG activity did not significantly differ between the PA and aorta in clinically active patients. In addition, 18F-FDG activity of the PA was positively correlated with inflammatory markers. Changes in 18F-FDG activity in PA during follow-up reflected therapeutic effects.

CONCLUSION

18F-FDG PET/CT can effectively evaluate PA activity in TA patients, and its diagnostic performance is superior to radiological imaging. The 18F-FDG activity of PA shows a good correlation with clinical disease status and inflammatory markers and can be used to monitor therapeutic effects.

FDG PET/CT Suggesting Pulmonary Artery Involvement of Takayasu Arteritis

Pulmonary artery involvement can occur in about half of the patients suffering Takayasu arteritis. Increased FDG activity in the aorta and its main branches in patients with Takayasu arteritis on PET/CT had been well-reported. However, the FDG PET/CT appearance of pulmonary artery involvement in Takayasu arteritis is less known. We present FDG PET/CT findings in a 37-year-old patient with known Takayasu arteritis. The images showed rim-like FDG activity in opacities in the left lung, which was later proven due to narrowed left main pulmonary artery.

F-18 FDG PET for assessment of disease activity of large vessel vasculitis: A systematic review and meta-analysis

BACKGROUND

The aim of this study is to investigate the performance of F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) or positron emission tomography/computed tomography (PET/CT) for the assessment of disease activity in patients with large vessel vasculitis (LVV) through a meta-analysis.

METHODS

The MEDLINE via PubMed and EMBASE were searched for the studies evaluating the performance of F-18 FDG PET or PET/CT in the assessment of disease activity in patients with LVV. Pooled sensitivity, specificity, diagnostic odds ratios (DORs), and summary receiver-operating characteristic (sROC) curve were estimated across the included studies. Possible publication bias was assessed by Deek's funnel plot asymmetry tests.

RESULTS

A total of 439 PET images from 298 patients pooled from nine studies showed that the pooled sensitivity was 0.88 [95% confidence interval (CI) 0.79-0.93] without heterogeneity (χ2 = 14.42, P = .07) and the pooled specificity was 0.81 (95% CI 0.64-0.91) with heterogeneity (χ2 = 63.72, P = .00) for the detection of active LVV. The pooled DOR was 30 (95% CI 8-107). Hierarchical sROC curve indicates that the area under the curve was 0.91 (95% CI 0.89-0.94). There was no significant publication bias (P = .42), and meta-regression analysis revealed that none of the variables was the source of the study heterogeneity.

CONCLUSIONS

F-18 FDG PET has a good performance for the detection of active disease status in patients with LVV. Revised criteria for the assessment of disease activity incorporated with F-18 FDG PET or PET/CT should be introduced and validated. Further studies are warranted to determine if PET-based treatment of LVV can improve outcomes.

FDG-PET/CT(A) imaging in large vessel vasculitis and polymyalgia rheumatica: joint procedural recommendation of the EANM, SNMMI, and the PET Interest Group (PIG), and endorsed by the ASNC

Large vessel vasculitis (LVV) is defined as a disease mainly affecting the large arteries, with two major variants, Takayasu arteritis (TA) and giant cell arteritis (GCA). GCA often coexists with polymyalgia rheumatica (PMR) in the same patient, since both belong to the same disease spectrum. FDG-PET/CT is a functional imaging technique which is an established tool in oncology, and has also demonstrated a role in the field of inflammatory diseases. Functional FDG-PET combined with anatomical CT angiography, FDG-PET/CT(A), may be of synergistic value for optimal diagnosis, monitoring of disease activity, and evaluating damage progression in LVV. There are currently no guidelines regarding PET imaging acquisition for LVV and PMR, even though standardization is of the utmost importance in order to facilitate clinical studies and for daily clinical practice. This work constitutes a joint procedural recommendation on FDG-PET/CT(A) imaging in large vessel vasculitis (LVV) and PMR from the Cardiovascular and Inflammation & Infection Committees of the European Association of Nuclear Medicine (EANM), the Cardiovascular Council of the Society of Nuclear Medicine and Molecular Imaging (SNMMI), and the PET Interest Group (PIG), and endorsed by the American Society of Nuclear Cardiology (ASNC). The aim of this joint paper is to provide recommendations and statements, based on the available evidence in the literature and consensus of experts in the field, for patient preparation, and FDG-PET/CT(A) acquisition and interpretation for the diagnosis and follow-up of patients with suspected or diagnosed LVV and/or PMR. This position paper aims to set an internationally accepted standard for FDG-PET/CT(A) imaging and reporting of LVV and PMR.

18 F-Fluorodeoxyglucose-Positron Emission Tomography As an Imaging Biomarker in a Prospective, Longitudinal Cohort of Patients With Large Vessel Vasculitis

OBJECTIVE

To assess the clinical value of ¹⁸ F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in a prospective cohort of patients with large vessel vasculitis (LVV) and comparator subjects.

METHODS

Patients with Takayasu arteritis and giant cell arteritis were studied, along with a comparator group consisting of patients with hyperlipidemia, patients with diseases that mimic LVV, and healthy controls. Participants underwent clinical evaluation and FDG-PET imaging, and patients with LVV underwent serial imaging at 6-month intervals. We calculated sensitivity and specificity of FDG-PET interpretation for distinguishing patients with clinically active LVV from comparator subjects and from patients with disease in clinical remission. A qualitative summary score based on global arterial FDG uptake, the PET Vascular Activity Score (PETVAS), was used to study associations between activity on PET scan and clinical characteristics and to predict relapse.

RESULTS

A total of 170 FDG-PET scans were performed in 115 participants (56 patients with LVV and 59 comparator subjects). FDG-PET distinguished patients with clinically active LVV from comparator subjects with a sensitivity of 85% (95% confidence interval [95% CI] 69, 94) and a specificity of 83% (95% CI 71, 91). FDG-PET scans were interpreted as active vasculitis in most patients with LVV in clinical remission (41 of 71 [58%]). Clinical disease activity status, disease duration, body mass index, and glucocorticoid use were independently associated with activity on PET scan. Among patients who underwent PET during clinical remission, future clinical relapse was more common in patients with a high PETVAS than in those with a low PETVAS (55% versus 11%; P = 0.03) over a median follow-up period of 15 months.

CONCLUSION

FDG-PET provides information about vascular inflammation that is complementary to, and distinct from, clinical assessment in LVV. FDG-PET scan activity during clinical remission was associated with future clinical relapse.

Takayasu Arteritis

Takayasu arteritis is an idiopathic granulomatous vasculitis of the aorta and its main branches and it constitutes one of the more common vasculitides in children. Inflammation and intimal proliferation lead to wall thickening, stenotic or occlusive lesions, and thrombosis, while destruction of the elastica and muscularis layers originates aneurysms and dissection. Carotid artery tenderness, claudication, ocular disturbances, central nervous system abnormalities, and weakening of pulses are the most frequent clinical features. The diagnosis is usually confirmed by the observation of large vessel wall abnormalities: stenosis, aneurysms, occlusion, and evidence of increased collateral circulation in angiography, MRA or CTA imaging. The purpose of this revision is to address the current knowledge on pathogenesis, investigations, classification, outcome measures and management, and to emphasize the need for timely diagnosis, effective therapeutic intervention, and close monitoring of this severe condition.

Effect of CRP value on 18F-FDG PET vascular positivity in Takayasu arteritis: a systematic review and per-patient based meta-analysis

PURPOSE

The aim of this study was to quantify the association between the CRP value and ¹⁸F-FDG PET vascular positivity in Takayasu arteritis (TAK) through a structured dedicated systematic review and meta-analysis.

METHODS

From January 2000 to December 2016, the PubMed/MEDLINE database was searched for articles specifically dealing with the assessment of vascular inflammation using ¹⁸F-FDG PET and CRP biomarkers in TAK. Inclusion criteria for the qualitative analysis were (1) ¹⁸F-FDG PET used to assess the disease activity, (2) The use of the ACR criteria for the diagnosis of TAK, (3) No case mixed vasculitis (i.e., no giant cell arteritis), and (4) CRP concentration and clinical disease activity available. For the meta-analysis, PET-positive and PET-negative subgroups with the corresponding CRP concentrations were generated based on per patient data. The standard mean difference, which represents the effect of the CRP concentrations on the ¹⁸F-FDG PET vascular uptake, was computed for all studies, and then the results were pooled together.

RESULTS

Among the 33 initial citations, nine complete articles including 210 patients fulfilled the inclusion criteria. Five studies found a significant correlation between the ¹⁸F-FDG PET and CRP concentration, one provided a trend towards association and three did not find any association between the two biomarkers. Six studies found a significant association between ¹⁸F-FDG PET and clinical disease activity, one found a trend towards association and the last two studies did not evaluate this correlation. The meta-analysis (121 patients) provided the following results: Standard Mean Deviation = 0.54 [0.15;0.92]; Chi² = 3.35; I² = 0%; Test for overall effect: Z = 2.70 (P = 0.007).

CONCLUSION

The CRP concentration only moderately reflects the ¹⁸F-FDG PET vascular positivity in TAK, suggesting dissociated information. Standardized longitudinal prospective studies are necessary to assess the value of ¹⁸F-FDG PET as an independent biomarker for subtle vascular wall inflammation detection.

Assessment of Therapy Response by FDG PET in Infection and Inflammation

Positron emission tomography (PET) is a well-known imaging modality in assessing the treatment response to chemotherapy or radiotherapy in various malignancies. A systematic review of the literature reveals a few publications reporting evaluation of the treatment response in benign conditions using PET/computed tomography. PET holds a promising future role in the follow-up of inflammatory or infectious diseases. In this article, [(18)F]Fluorodeoxyglucose PET as a tool in the evaluation, treatment, and follow-up of infectious and inflammatory diseases is discussed.

Management of the renovascular disease in children with Takayasu arteritis

Takaysu arteritis (TA), together with fibromuscular dysplasia, is the most common cause for renovascular hypertension. The diagnosis of vasculitis is important to make as these children benefit from immunosuppressive treatment. In many cases, however, it is more difficult than commonly realised to differentiate between these two diagnoses. Imaging which allows the inflamed arterial wall to be outlined, such as magnetic resonance or positron emission tomography scans, can be very helpful in this context. Revascularisation, either with angioplasty or surgery, seems to be effective and safe, also in children with TA. Patients with inactive disease have a more successful outcome and experience fewer complications from the intervention than those with active on-going inflammation.

Patients with Takayasu's arteritis having persistent acute-phase response usually have an increased major vessel uptake by 18F-FDG-PET/CT

OBJECTIVES

Although not uniformly accepted, an increased uptake by 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in large vessels is accepted to be a sign of active disease in Takayasu's arteritis (TAK). We aimed to investigate the value of 18F-FDG-PET/CT for clinical assessment in a subset of TAK patients having a persistent acute-phase response (APR) without any signs or symptoms of clinical disease activity.

METHOD

We studied 14 patients (mean age: 38.6 ± 13.9 years, Female/Male: 11/3, and disease duration: 5.7 ± 5 years). Patients were clinically inactive (according to the definition of activity by Kerr et al.), while categorized as having "persistent" disease activity by physician's global assessment due only to APR. 18F-FDG uptake was graded using a four-point scale from grade 0 (no uptake present) to grade 3 (high grade: uptake higher than that of liver). Any uptake in major vessels with a grade ≥ 2 was accepted to be "active."

RESULTS

Mean erythrocyte sedimentation rate was 50.8 ± 13.2 mm/hour and mean C-reactive protein level was 28.5 ± 22.1 mg/L. Active vasculitic lesions were observed by 18F-FDG-PET/CT in 9 of 14 (64.3%) patients. The median number of active vascular lesions was 2 (range: 1-5). A step-up treatment change was decided in 8 patients according to 18F-FDG-PET/CT results.

CONCLUSION

We observed increased 18F-FDG uptake in the majority of TAK patients with an increased APR, but clinically silent disease. 18F-FDG-PET/CT showed the presence and localization of active inflammation in the aorta and its branches. Although specificity for observed lesions is not clear, 18F-FDG-PET/CT imaging may influence physician's assessment of clinical activity and treatment choices in TAK.

FDG PET/CT in infection and inflammation--current and emerging clinical applications

Integrated positron emission tomography/computed tomography (PET/CT) with the glucose analogue, 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG), is an evolving hybrid imaging technique in the evaluation of an important and diverse group of pathological conditions, which are characterised by infection and aseptic inflammation. With a rapidly expanding body of evidence, it is being increasingly recognised that, in addition to its established role in oncological imaging, FDG PET/CT also has clinical utility in suspected infection and inflammation. The technique can identify the source of infection or inflammation in a timely fashion ahead of morphological changes on conventional anatomical imaging techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI), map the extent and severity of disease, identify sites for tissue sampling, and assess therapy response. FDG PET/CT exhibits distinct advantages over traditional radionuclide imaging techniques in terms of shorter duration of examination, higher spatial resolution, non-invasive nature of acquisition, ability to perform quantitative analyses, and the provision of a synergistic combination of functional and anatomical imaging. With the use of illustrative clinico-radiological cases, this article discusses the current and emerging evidence for the use of FDG PET/CT in a broad spectrum of disorders, such as fever of unknown origin, sarcoidosis, large vessel vasculitis, musculoskeletal infections, joint prosthesis or implant-related complications, human immunodeficiency virus (HIV)-related infections, and miscellaneous indications, such as IgG4-related systemic disease. It will also briefly summarise the role of more novel tracers such as FDG-labelled leukocytes and gallium-68 PET tracers in this arena.

Management of large-vessel vasculitis with FDG-PET: a systematic literature review and meta-analysis

We aimed to clarify the role of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in the management of large-vessel vasculitis (LVV), focusing on 3 issues which are as follows: describe and determine the different FDG-PET criteria for the diagnosis of vascular inflammation, the performance of FDG-PET for the diagnosis of large-vessel inflammation in giant cell arteritis (GCA) patients, and the performance of FDG-PET to evaluate the disease inflammatory activity in Takayasu arteritis (TA) patients. MEDLINE, Cochrane Library, and EMBASE database were searched for articles that evaluated the value of FDG-PET in LVV, from January 2000 to December 2013. Inclusion criteria were American College of Rheumatology criteria for GCA or TA, definition PET positivity threshold, and >4 cases included. Sensitivity (Se) and specificity (Sp) of FDG-PET for the diagnosis of large-vessel inflammation were calculated from each included individual study, and then pooled for meta-analysis with a random-effects model. Twenty-one studies (413 patients, 299 controls) were included in the systematic review. FDG-PET showed FDG vascular uptake in 70% (288/413) of patients and 7% (22/299) of controls. Only vascular uptake equal to or higher than the liver uptake was significantly different between GCA/TA patients and controls (P < 0.001). The meta-analysis of GCA patients (4 studies, 57 patients) shows that FDG-PET has high Se and Sp for the diagnosis of large-vessel inflammation in GCA patients in comparison to controls, with a pooled Se at 90% (95% confidence interval [CI], 79%-93%) and a pooled Sp at 98% (95% CI, 94%-99%). The meta-analysis of TA patients (7 studies, 191 patients) shows that FDG-PET has a pooled Se at 87% (95% CI, 78%-93%) and Sp at 73% (95% CI, 63%-81%) for the assessment of disease activity in TA, with up to 84% Sp, with studies using National Institutes of Health criteria as the disease activity assessment scale. FDG-PET showed good performances in the diagnosis of large-vessel inflammation, with higher accuracy in GCA patients than in TA patients. Although a vascular uptake equal to or higher than the liver uptake appears to be a good criterion for the diagnosis of vascular inflammation, further studies are needed to define the threshold of significance as well as the clinical significance of the vascular uptake.

Outcome of takayasu arteritis with inactive disease at diagnosis: the extent of vascular involvement as a predictor of activation

OBJECTIVE

Some patients with Takayasu arteritis (TA) have inactive disease at the time of diagnosis. The objective of our study was to investigate the clinical outcomes and factors that predict disease activation in patients with clinically inactive TA.

METHODS

The medical records of patients diagnosed with TA between 1990 and 2012 were reviewed. At the time of diagnosis, patients were identified as having inactive disease according to the National Institutes of Health definition. Patients who went on to develop active disease during followup were classified as the "activation group". The pattern of vascular involvement was classified according to the International Conference on TA, 1994.

RESULTS

A total of 59 patients with TA were classified as having inactive disease at the time of diagnosis. During the followup, 13 (22.0%) of these experienced TA activation (median followup, 37.0 mos; activation group). The remaining 46 (78.0%) did not experience disease activation (stable group). Renovascular hypertension was more common in the activation group than in the stable group (5/13, 38.5% vs 4/46, 8.7%, p = 0.019). Further, type V, which is the most extensive, was more common in the activation group (12/13, 92.3%) than in the stable group (18/46, 39.1%, p = 0.008). Multivariate analysis identified type V disease (OR 10.969, 95% CI 1.144-105.182, p = 0.038) as being significantly associated with an increased risk of disease activation.

CONCLUSION

Substantial portions of patients with clinically inactive TA at the time of diagnosis experienced disease activation during followup. Type V disease may be an important predictive factor for disease activation in patients with clinically inactive TA.

Giant cell arteritis exclusively detected by 18F-fluorodeoxyglucose positron emission tomography: a case report

Introduction

This case of giant cell arteritis is noteworthy because it evaded standard diagnostic criteria and only emerged as fever of unknown origin. In this regard, we present ¹⁸F-fluorodeoxyglucose positron emission tomography as a valid diagnostic method.

Case presentation

This case report describes a 58-year-old Caucasian woman who is a cigarette smoker with a 10-week history of fever of unknown origin, night sweats and weight loss of 12kg. Initially, clinical presentation was suspicious of malignant disease. Laboratory findings detected significantly elevated inflammatory blood parameters including C-reactive protein and elevated erythrocyte sedimentation rate (110mm/hour). Extensive diagnostic workup including microbiological and rheumatological assessment, ultrasonography, endoscopy and computed tomography of abdomen and thorax did not indicate any septic or malignant focus. Eventually, ¹⁸F-fluorodeoxyglucose positron emission tomography was able to reveal arteritis of her aortic arch and supraaortic branches. Subsequently, she commenced steroid and methotrexate therapy that led to sustained remission.

Conclusions

This case of giant cell arteritis may promote discussion regarding a more specific classification for this disease entity. Furthermore, it confirms that ¹⁸F-fluorodeoxyglucose positron emission tomography might serve as a valuable tool for diagnosis of giant cell arteritis, because it could facilitate an accurate and non-invasive detection of lesions of large vessels.

F-18 FDG PET/CT in the evaluation of Takayasu arteritis: an experience from the tropics

OBJECTIVE

To evaluate the performance parameters of FDG PET/CT in patients with Takayasu arteritis at diagnosis and during immunosuppression.

METHODS

Retrospective analysis of 60 FDG PET/CT studies in 51 patients was performed (17 scans at diagnosis out of which 4 had follow-up scans also and 43 scans on immunosuppression). The degree of FDG uptake in the vessels was assessed visually using a 4-point scale and maximum standardized uptake value (SUVmax), SUVratio, extent of vasculitis and association with ESR were calculated.

RESULTS

PET/CT was positive for active vasculitis in all 17 patients at diagnosis. The mean SUVmax and mean SUV ratio of the active areas were 5.1 ± 3.0 and 3.2 ± 1.9, respectively. On immunosuppression, PET scan was positive for active vasculitis in 14/43 (32.5%) scans. The mean SUVmax and mean SUVratio of the active areas were 1.7 ± 2.1 and 0.95 ± 1.2, respectively. There was significant difference between the mean SUVmax and mean SUVratio at diagnosis and on immunosuppression, respectively (P < .01). The median number of vascular segments in each uptake grade group was also statistically different (P < .01) between scans at diagnosis and on immunosuppression. The median ESR level in PET positive scans was 29 mm/hour (2-53), whereas in PET negative scans was 35.5 mm/hour (6-50) and the difference was not statistically significant.

CONCLUSION

FDG PET/CT showed good sensitivity to detect active vasculitis at diagnosis and during immunosuppression. The change in SUVmax between the successive FDG PET/CT scans may give an objective assessment of response to immunosuppression.

[Update on the use of PET radiopharmaceuticals in inflammatory disease]

The use of molecular imaging with PET/CT technology using different radiotracers, especially the (18)F-FDG is currently spreading beyond the area of oncology, the most interest being placed on inflammatory and infectious diseases. This article presents a review of its contribution in different inflammatory conditions in the context of structural and conventional nuclear medicine imaging. Special emphasis is placed on the more significant diseases such as large-vessel vasculitis, sarcoidosis, rheumatoid arthritis and inflammatory bowel disease and the study of the atheroma plaque.

Renovascular hypertension--is it fibromuscular dysplasia or Takayasu arteritis

Renovascular hypertension (RVH) can be caused by many different diseases, with the most common being fibromuscular dysplasia (FMD) and Takayasu arteritis (TA). A strikingly different diagnostic pattern is seen in children with RVH from different parts of the world. In Europe and North America, these children are mainly diagnosed as having FMD while in Asia and South Africa they will most often get a diagnosis of TA. When comparing the clinical diagnosis for FMD and TA, it becomes obvious that there is a great deal of overlap between the definitions of these two conditions. Different ways to come to the most accurate diagnosis using imaging of the blood vessel wall and positron emission tomography (PET) will be discussed. How an accurate diagnosis should influence the treatment of the children with these conditions will also be addressed.

[How to manage Takayasu arteritis?]

Thorough clinical and imaging assessment of the arterial tree when a diagnosis of Takayasu arteritis is established. Glucocorticoïd as intiation therapy. Immunosuppresive agent should be considered as adjunctive therapy if resistance or dependance to glucocorticoïd therapy. Supportive care, antihypertensive drugs, glucocorticoïd induced osteoporosis preventive therapy, tuberculosis screening should not be forgiven. Monitoring of therapy should be clinical and supported by biological markers and imaging. Reconstructive surgery should be performed in the quiescent phase of disease.

FDG PET Imaging of Large-Vessel Vasculitis

Diagnosis of vasculitis is challenging given the nonspecific manifestations of the diseases. [(18)F]Fluorodeoxyglucose (FDG) positron emission tomography (PET) has been increasingly used for vasculitis in clinic and has been shown to have a potential role in diagnosing large-vessel vasculitis such as giant cell vasculitis and Takayasu vasculitis, in monitoring treatment response, and in predicting disease progression. However, the exact clinical role of FDG PET for vasculitis has not been determined. Diagnosis of vasculitis should not be made solely based on PET. It is also worth noting that FDG PET has limited role in small-size vasculitis, although case reports have shown some success.

Blind runner

Bilateral ocular ischemic syndrome and ischemic optic neuropathy have rarely been reported as initial manifestations of Takayasu arteritis (TA). Appearance of ocular symptoms in TA is related to the extent and severity of involvement of the aorta and its major branches. We report a case of bilateral ocular ischemic syndrome with unilateral ischemic optic neuropathy secondary to TA in a 42-year-old Pakistani man who had severe ocular and cerebral ischemia.

PET in vasculitis

[(18) F]Fluorodeoxyglucose positron emission tomography (FDG PET) can be used to visualize large-vessel inflammation in giant-cell arteritis, Takayasu arteritis, and other types of aortitis. In patients with symptoms compatible with polymyalgia rheumatica, findings of increased FDG-uptake in the shoulders, hips, as well as the spinous processes of the cervical and lumbar spine, may suggest this diagnosis. In patients with giant-cell arteritis, there is increased metabolic activity within the aortic wall on FDG PET scintigraphy, indicating inflammation of the aorta, which may be a predictor of a higher potential for aortic dilatation.

Usefulness of whole-body fluorine-18-fluorodeoxyglucose positron emission tomography in patients with large-vessel vasculitis: a systematic review

The objective of this study is to systematically review the role of positron emission tomography (PET) and PET/computed tomography (PET/CT) with fluorine-18-fluorodeoxyglucose (FDG) in patients with large-vessel vasculitis (LVV). A comprehensive literature search of published studies through April 2011 in PubMed/MEDLINE and Scopus databases regarding whole-body FDG-PET and PET/CT in patients with LVV was performed. We identified 32 studies including 604 LVV patients. The main findings of these studies are presented. The conclusions are the following: (1) FDG-PET and PET/CT are useful imaging methods in the initial diagnosis and in the assessment of activity and extent of disease in patients with LVV; (2) the correlation between FDG-PET findings and serological levels of inflammatory markers, as well as the usefulness of FDG-PET and PET/CT in evaluating treatment response, remains unclear; (3) it appears that there is a superiority of FDG-PET and PET/CT over conventional imaging methods in the diagnosis of LVV, but not in assessing disease activity under immunosuppressive treatment, in predicting relapse or in evaluating vascular complications; and (4) given the heterogeneity between studies with regard to PET analysis and diagnostic criteria, a standardization of the technique is needed.

[Useful imaging techniques in the diagnosis and follow up of large vessel vasculitis: eco-doppler, angio-CT, angio-RM]

Although most vasculitis require histological proof for a definitive diagnosis, diagnostic imaging can be very helpful in this regard, allowing a proper evaluation of the vascular system and monitoring the response to treatment. Even though vasculitis is constituted by different pathological substrates, they show a common semiologic pattern from a radiological standpoint which is represented by inflammation, arterial wall thickening, and potential secondary development of vascular stenosis, occlusions or aneurysms. Differential diagnosis among diverse entities is based, beside clinical criteria, on the anatomical location and topography of the affected vascular territory. The general radiologic semiology is described in this paper from the perspective of the different imaging techniques, addressing their main advantages and drawbacks. Proper knowledge of this techniques will allow us to select the most appropiate one for each clinical condition.

Development of outcome measures for large-vessel vasculitis for use in clinical trials: opportunities, challenges, and research agenda

Giant cell (GCA) and Takayasu's arteritis (TAK) are 2 forms of large-vessel vasculitis (LVV) that involve the aorta and its major branches. GCA has a predilection for the cranial branches, while TAK tends to affect the extracranial branches. Both disorders may also cause nonspecific constitutional symptoms. Although some clinical features are more common in one or the other disorder and the ages of initial presentation differ substantially, there is enough clinical and histopathologic overlap between these disorders that some investigators suggest GCA and TAK may be 2 processes within the spectrum of a single disease. There have been few randomized therapeutic trials completed in GCA, and none in TAK. The lack of therapeutic trials in LVV is only partially explained by the rarity of these diseases. It is likely that the lack of well validated outcome measures for LVV and uncertainties regarding trial design contribute to the paucity of trials for these diseases. An initiative to develop a core set of outcome measures for use in clinical trials of LVV was launched by the international OMERACT Vasculitis Working Group in 2009 and subsequently endorsed by the OMERACT community at the OMERACT 10 meeting. Aims of this initiative include: (1) to review the literature and existing data related to outcome assessments in LVV; (2) to obtain the opinion of experts and patients on disease content; and (3) to formulate a research agenda to facilitate a more data-based approach to outcomes development.

[New aspects of MRI for diagnostics of large vessel vasculitis and primary angiitis of the central nervous system]

Vasculitis is a rare disease and clinical symptoms are often unspecific. Accurate and early diagnosis is mandatory in order to prevent complications, such as loss of vision or stroke. Imaging techniques can contribute to establishing a definite diagnosis and to evaluate disease activity and the extent of the disease in various vascular regions. Conventional imaging methods, such as computed tomography (CT) and magnetic resonance (MR) angiography, as well as digital subtraction angiography allow the vessel lumen but not the vessel wall to be depicted. However, vasculitis is a disease which primarily affects the vessel wall, therefore conventional imaging modalities often fail to make a definite diagnosis. Recently black-blood high resolution MR in vivo imaging has been used to visualize cervical and intracranial vasculitis. This review article presents imaging protocols for intracranial and cervical black-blood MR imaging and clinical cases with large vessel vasculitis and vasculitis of the central nervous system. Furthermore the current literature, examples of the most common differential diagnoses of cervical and cranial arteriopathy and the potential of other imaging modalities, such as PET/CT and ultrasound will be discussed.

18F-Fludeoxyglucose PET/CT in the evaluation of large-vessel vasculitis: diagnostic performance and correlation with clinical and laboratory parameters

OBJECTIVE

To investigate the diagnostic performance of (18)F-fludeoxyglucose ((18)F-FDG) positron emission tomography (PET)/CT in patients with suspected large-vessel vasculitis and its potential to evaluate the extent and activity of disease.

METHODS

78 consecutive patients (mean age 63 years; 53 females) with suspected large-vessel vasculitis were evaluated with (18)F-FDG PET/CT.( 18)F-FDG uptake in the aorta and major branches was visually graded using a four-point scale and quantified with standardised uptake values (SUV(max)). According to clinical diagnosis, patients were classified into three groups: (a) steroid-naïve, large-vessel vasculitis (16 patients), (b) vasculitis on steroid treatment (18 patients) and (c) no evidence of vasculitis (44 patients). Analysis of variance and linear regression were used to investigate the association of (18)F-FDG uptake with clinical diagnosis and inflammatory markers.

RESULTS

(18)F-FDG PET/CT was positive (visual uptake ≥ 2; equal to or greater than liver) in all patients with steroid-naïve, large-vessel vasculitis. The thoracic aorta, the carotid and the subclavian arteries were most frequently involved. In these patients, SUV(max) values were significantly higher than in the other groups (analysis of variance; p<0.05). Linear regression showed a significant positive association (b-coefficients: 0.018-0.02; p<0.05) between SUV(max) of the thoracic aorta and inflammatory markers in patients with vasculitis (Groups a and b). Patients on steroid treatment showed low visual scores (uptake <2) and significantly lower SUV(max) values than steroid-naïve patients.

CONCLUSION

(18)F-FDG PET/CT can detect the extent and activity of large-vessel vasculitis in untreated patients and is unreliable in diagnosing vasculitis in patients on steroids.