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

Effectiveness Of Tocilizumab In Aortitis And Aneurysms Associated With Giant Cell Arteritis

OBJECTIVE

Aortitis in Giant Cell Arteritis (GCA-aortitis) is a frequent complication that may lead to aneurysms. Tocilizumab (TCZ) was approved in GCA, but the efficacy in GCA-aortitis and aneurysms has not been analyzed to date. Our aim was to assess the effectiveness and safety of TCZ in a wide series of GCA-aortitis and aneurysms.

METHODS

Multicentre observational study with GCA-aortitis treated with TCZ. GCA was diagnosed by: a) ACR criteria, b) temporal artery biopsy, and/or c) imaging techniques. Aortitis was diagnosed mainly by PET/CT. Main outcomes were EULAR and imaging remission. Others were clinical remission, analytical normalization, corticosteroid-sparing effect, and the prevention and improvement of aneurysms.

RESULTS

196 patients with GCA-aortitis treated with TCZ. After 6 months, 72.2% reached EULAR remission but only 12% an imaging remission; increasing up-to 81.4% and 31.8%, respectively, at 24 months. A rapid clinical remission, ESR and CRP normalization was observed in 47.4%, 84.3% and 55.6%, at 1 month, increasing to 89.6%, 85.3% and 80.3% at 24 months, respectively. Aneurysms were present in 10 (5%) patients. Five of them required early surgery, while 3 others enlarged. No patient on TCZ therapy developed aneurysms during follow-up.

CONCLUSION

In patients with GCA-aortitis treated with TCZ, a rapid and maintained clinical and analytical improvement was observed. However, there was an uncoupling between clinical and EULAR remission with imaging remission.

Automated multiclass segmentation, quantification, and visualization of the diseased aorta on hybrid PET/CT-SEQUOIA

BACKGROUND

Cardiovascular disease is the most common cause of death worldwide, including infection and inflammation related conditions. Multiple studies have demonstrated potential advantages of hybrid positron emission tomography combined with computed tomography (PET/CT) as an adjunct to current clinical inflammatory and infectious biochemical markers. To quantitatively analyze vascular diseases at PET/CT, robust segmentation of the aorta is necessary. However, manual segmentation is extremely time-consuming and labor-intensive.

PURPOSE

To investigate the feasibility and accuracy of an automated tool to segment and quantify multiple parts of the diseased aorta on unenhanced low-dose computed tomography (LDCT) as an anatomical reference for PET-assessed vascular disease.

METHODS

A software pipeline was developed including automated segmentation using a 3D U-Net, calcium scoring, PET uptake quantification, background measurement, radiomics feature extraction, and 2D surface visualization of vessel wall calcium and tracer uptake distribution. To train the 3D U-Net, 352 non-contrast LDCTs from (2-[18F]FDG and Na[18F]F) PET/CTs performed in patients with various vascular pathologies with manual segmentation of the ascending aorta, aortic arch, descending aorta, and abdominal aorta were used. The last 22 consecutive scans were used as a hold-out internal test set. The remaining dataset was randomly split into training (n = 264; 80%) and validation (n = 66; 20%) sets. Further evaluation was performed on an external test set of 49 PET/CTs. The dice similarity coefficient (DSC) and Hausdorff distance (HD) were used to assess segmentation performance. Automatically obtained calcium scores and uptake values were compared with manual scoring obtained using clinical softwares (syngo.via and Affinity Viewer) in six patient images. intraclass correlation coefficients (ICC) were calculated to validate calcium and uptake values.

RESULTS

Fully automated segmentation of the aorta using a 3D U-Net was feasible in LDCT obtained from PET/CT scans. The external test set yielded a DSC of 0.867 ± 0.030 and HD of 1.0 [0.6-1.4] mm, similar to an open-source model with a DSC of 0.864 ± 0.023 and HD of 1.4 [1.0-1.8] mm. Quantification of calcium and uptake values were in excellent agreement with clinical software (ICC: 1.00 [1.00-1.00] and 0.99 [0.93-1.00] for calcium and uptake values, respectively).

CONCLUSIONS

We present an automated pipeline to segment the ascending aorta, aortic arch, descending aorta, and abdominal aorta on LDCT from PET/CT and to accurately provide uptake values, calcium scores, background measurement, radiomics features, and a 2D visualization. We call this algorithm SEQUOIA (SEgmentation, QUantification, and visualizatiOn of the dIseased Aorta) and is available at https://github.com/UMCG-CVI/SEQUOIA. This model could augment the utility of aortic evaluation at PET/CT studies tremendously, irrespective of the tracer, and potentially provide fast and reliable quantification of cardiovascular diseases in clinical practice, both for primary diagnosis and disease monitoring.

[Clinical characteristics and follow-up of 60 patients with recent diagnosis of giant cell arteritis, NEWTON study]

INTRODUCTION

The management of giant cell arteritis (GCA) has evolved with the arrival of tocilizumab (TCZ) and the use of PET/CT. Our objective is to describe the characteristics and followup of patients with recent diagnosis of GCA in current care.

PATIENTS AND METHODS

The NEWTON cohort is a monocentric retrospective cohort based on data collected from 60 GCA patients diagnosed between 2017 and 2022 according to the ACR/EULAR 2022 criteria.

RESULTS

The median age at diagnosis was 73 [68.75; 81] years old. At diagnosis, the main manifestations were unusual temporal headaches in 48 (80 %) and an inflammatory syndrome in 50 (83 %) patients. Temporal artery biopsy confirmed the diagnosis in 49/58 (84 %) patients. Doppler of the temporal arteries found a halo in 12/23 (52 %) patients. The PET/CT found hypermetabolism in 19/43 (44 %) patients. Prednisone was stopped in 17.5 [12.75; 24.25] months. During follow-up, 22 (37 %) patients received TCZ. At least one complication of corticosteroid therapy was observed in 22 (37 %) patients. After a median follow-up of 24 [12; 42] months, 25 (42 %) patients relapsed. At the end of the follow-up, 29 (48.3 %) patients were weaned from corticosteroid therapy and 15 (25 %) were on TCZ.

CONCLUSION

Despite the increasing use of TCZ in the therapeutic arsenal and of the PET/CT in the imaging tools of GCA patients, relapses and complications of corticosteroid therapy remain frequent, observed in more than a third of patients.

Imaging to predict early relapses after treatment discontinuation in patients with large vessel giant cell arteritis - A cohort study

OBJECTIVES

To investigate the value of [18F]fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) in predicting relapse after treatment discontinuation in patients with large-vessel giant cell arteritis (LV-GCA).

METHODS

This study included patients with LV-GCA whose treatment was discontinued between 2018 and 2023. All patients underwent PET/CT and/or MRI at the time of treatment discontinuation in clinical remission. Qualitative and quantitative PET/CT scores, by measuring standardized uptake values (SUV), and semiquantitative MRI scores of the aorta and supraaortic vessels were compared between patients who relapsed within 4 months after treatment discontinuation and those who did not.

RESULTS

Forty patients were included (median age 67.4 years, interquartile range (IQR) 60.8-74.0; 77.5 % females). Eleven patients (27.5 %) relapsed after treatment discontinuation (time to relapse 1.9 months, IQR 1.4-3.3). Patients who relapsed were comparable to those who remained in remission with respect to the presence of active vasculitis on MRI and/or PET/CT (54.5% vs. 58.6 %, p = 1.0), the number of segments with vasculitic findings on MRI (0, IQR 0.0-1.5, vs. 2, IQR 0.0-3.0, p = 0.221) or the highest SUV artery/liver ratio on PET/CT (1.5, IQR 1.4-1.6, vs. 1.3, IQR 1.2-1.6, p = 0.505). The median number of vasculitic segments on PET/CT was 2.5 (IQR 0.5-4.5) in those with vs. 0 (IQR 0.0-1.5, p = 0.085) in those without relapse, and the PET/CT scores 4.5 (IQR 0.75-8.25) vs. 0 (IQR 0.0-3.0, p = 0.172).

CONCLUSION

PET/CT or MRI at treatment stop did not predict relapse and may not be suited to guide treatment decisions in patients with LV-GCA in remission.

Broadening the clinical spectrum of giant cell arteritis: from the classic cranial to the predominantly extracranial pattern of the disease

INTRODUCTION

Giant cell arteritis (GCA) is a large vessel (LV) vasculitis that affects people aged 50 years and older. Classically, GCA was considered a disease that involved branches of the carotid artery. However, the advent of new imaging techniques has allowed us to reconsider the clinical spectrum of this vasculitis.

AREASCOVERED

This review describes clinical differences between patients with the cranial GCA and those with a predominantly extracranial LV-GCA disease pattern. It highlights differences in the frequency of positive temporal artery biopsy depending on the predominant disease pattern and emphasizes the relevance of imaging techniques to identify patients with LV-GCA without cranial ischemic manifestations. The review shows that so far there are no well-established differences in genetic predisposition to GCA regardless of the predominant phenotype.

EXPERT COMMENTARY

The large branches of the extracranial arteries are frequently affected in GCA. Imaging techniques are useful to identify the presence of 'silent' GCA in people presenting with polymyalgia rheumatica or with nonspecific manifestations. Whether these two different clinical presentations of GCA constitute a continuum in the clinical spectrum of the disease or whether they may be related but are definitely different conditions needs to be further investigated.

EULAR recommendations for the use of imaging in large vessel vasculitis in clinical practice: 2023 update

OBJECTIVES

To update the EULAR recommendations for the use of imaging modalities in primary large vessel vasculitis (LVV).

METHODS

A systematic literature review update was performed to retrieve new evidence on ultrasound, MRI, CT and [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) for diagnosis, monitoring and outcome prediction in LVV. The task force consisted of 24 physicians, health professionals and patients from 14 countries. The recommendations were updated based on evidence and expert opinion, iterating until voting indicated consensus. The level of agreement was determined by anonymous votes.

RESULTS

Three overarching principles and eight recommendations were agreed. Compared to the 2018 version, ultrasound is now recommended as first-line imaging test in all patients with suspected giant cell arteritis, and axillary arteries should be included in the standard examination. As an alternative to ultrasound, cranial and extracranial arteries can be examined by FDG-PET or MRI. For Takayasu arteritis, MRI is the preferred imaging modality; FDG-PET, CT or ultrasound are alternatives. Although imaging is not routinely recommended for follow-up, ultrasound, FDG-PET or MRI may be used for assessing vessel abnormalities in LVV patients with suspected relapse, particularly when laboratory markers of inflammation are unreliable. MR-angiography, CT-angiography or ultrasound may be used for long-term monitoring of structural damage, particularly at sites of preceding vascular inflammation.

CONCLUSIONS

The 2023 EULAR recommendations provide up-to-date guidance for the role of imaging in the diagnosis and assessment of patients with LVV.

PET/CT in Inflammatory and Auto-immune Disorders: Focus on Several Key Molecular Concepts, FDG, and Radiolabeled Probe Perspectives

Chronic immune diseases mainly include autoimmune and inflammatory diseases. Managing chronic inflammatory and autoimmune diseases has become a significant public health concern, and therapeutic advancements over the past 50 years have been substantial. As therapeutic tools continue to multiply, the challenge now lies in providing each patient with personalized care tailored to the specifics of their condition, ushering in the era of personalized medicine. Precise and holistic imaging is essential in this context to comprehensively map the inflammatory processes in each patient, identify prognostic factors, and monitor treatment responses and complications. Imaging of patients with inflammatory and autoimmune diseases must provide a comprehensive view of the body, enabling the whole-body mapping of systemic involvement. It should identify key cellular players in the pathology, involving both innate immunity (dendritic cells, macrophages), adaptive immunity (lymphocytes), and microenvironmental cells (stromal cells, tissue cells). As a highly sensitive imaging tool with vectorized molecular probe capabilities, PET/CT can be of high relevance in the management of numerous inflammatory and autoimmune diseases. Relying on key molecular concepts of immunity, the clinical usefulness of FDG-PET/CT in several relevant inflammatory and immune-inflammatory conditions, validated or emerging, will be discussed in this review, together with radiolabeled probe perspectives.

Multimodality imaging to assess diagnosis and evaluate complications of large vesselarteritis

Different types of vasculitis can be distinguished according to the blood vessel's size that is preferentially affected: large-vessel, medium-vessel, and small-vessel vasculitides. Giant cell arteritis (GCA) and Takayasu's arteritis (TAK) are the main forms of large-vessel vasculitis, and may lead to lumen narrowing. Clinical manifestations of arterial narrowing on the short- and long term include vision loss, stroke, limb ischemia, and heart failure. Imaging tools are well established diagnostic tests for large-vessel vasculitis and may aid therapy monitoring in selected cases while providing important information regarding the occurrence of vascular damage, tissue and organ complications. This review aims to provide the current status of multimodality imaging for the diagnosis and identification of vascular complications in the field of large vessel vasculitis.

Development of the Takayasu Arteritis Integrated Disease Activity Index

OBJECTIVE

Accurate clinical assessment of disease activity in Takayasu arteritis (TAK) can be challenging. 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) can directly measure vascular inflammation. This study details the development of a new type of disease activity index called the Takayasu's Arteritis Integrated Disease Activity Index (TAIDAI).

METHODS

Clinical symptoms for TAIDAI were identified from a literature review. Each symptom was paired with FDG-PET findings in corresponding arterial territories. Constitutional symptoms were paired with acute phase reactant levels. One point was given for each clinical symptom paired with supporting FDG-PET or laboratory abnormalities and summed into the TAIDAI score. A TAIDAI of ≥1 defined active disease. To assess performance of TAIDAI, face validity, content validity, and sensitivity to change were evaluated within a prospective observational cohort study of patients with TAK.

RESULTS

Seventeen clinical symptoms were paired with imaging or laboratory abnormalities. In a cohort of 96 patients contributing 204 study visits, TAIDAI showed excellent sensitivity (96.3%) and good specificity (79.2%) compared to physician's clinical assessment. TAIDAI significantly correlated with physician global assessment, PET Vascular Activity Score, patient global assessment, and acute phase reactant levels. In patients treated with either tumor necrosis factor inhibitors or tocilizumab, a TAIDAI of 0 was achieved in 21 (91%) of 23 patients who met a predefined definition of clinical response.

CONCLUSION

TAIDAI is new type of disease activity index in TAK in which clinical symptoms are integrated with specific laboratory and imaging findings. TAIDAI should be validated in future randomized controlled trials in TAK.

Establishing clinical remission criteria for giant cell arteritis: Results of a Delphi exercise carried out by an expert panel of the Japan Research Committee of the Ministry of Health, Labour, and Welfare for Intractable Vasculitis

OBJECTIVE

To develop a proposal for giant cell arteritis remission criteria in order to implement a treat-to-target algorithm.

METHODS

A task force consisting of 10 rheumatologists, 3 cardiologists, 1 nephrologist, and 1 cardiac surgeon was established in the Large-vessel Vasculitis Group of the Japanese Research Committee of the Ministry of Health, Labour and Welfare for Intractable Vasculitis to conduct a Delphi survey of remission criteria for giant cell arteritis. The survey was circulated among the members over four reiterations with four face-to-face meetings. Items with a mean score of ≥4 were extracted as items for defining remission criteria.

RESULTS

An initial literature review yielded a total of 117 candidate items for disease activity domains and treatment/comorbidity domains of remission criteria, of which 35 were extracted as disease activity domains (systematic symptoms, signs and symptoms of cranial and large-vessel area, inflammatory markers, and imaging findings). For the treatment/comorbidity domain, ≤5 mg/day of prednisolone 1 year after starting glucocorticoids was extracted. The definition of achievement of remission was the disappearance of active disease in the disease activity domain, normalization of inflammatory markers, and ≤5 mg/day of prednisolone.

CONCLUSION

We developed proposals for remission criteria to guide the implementation of a treat-to-target algorithm for giant cell arteritis.

Incidence and clinical manifestations of giant cell arteritis in Spain: results of the ARTESER register

OBJECTIVE

This study aimed to estimate the incidence of giant cell arteritis (GCA) in Spain and to analyse its clinical manifestations, and distribution by age group, sex, geographical area and season.

METHODS

We included all patients diagnosed with GCA between 1 June 2013 and 29 March 2019 at 26 hospitals of the National Health System. They had to be aged ≥50 years and have at least one positive results in an objective diagnostic test (biopsy or imaging techniques), meet 3/5 of the 1990 American College of Rheumatology classification criteria or have a clinical diagnosis based on the expert opinion of the physician in charge. We calculated incidence rate using Poisson regression and assessed the influence of age, sex, geographical area and season.

RESULTS

We identified 1675 cases of GCA with a mean age at diagnosis of 76.9±8.3 years. The annual incidence was estimated at 7.42 (95% CI 6.57 to 8.27) cases of GCA per 100 000 people ≥50 years with a peak for patients aged 80-84 years (23.06 (95% CI 20.89 to 25.4)). The incidence was greater in women (10.06 (95% CI 8.7 to 11.5)) than in men (4.83 (95% CI 3.8 to 5.9)). No significant differences were found between geographical distribution and incidence throughout the year (p=0.125). The phenotypes at diagnosis were cranial in 1091 patients, extracranial in 337 patients and mixed in 170 patients.

CONCLUSIONS

This is the first study to estimate the incidence of GCA in Spain at a national level. We found a predominance among women and during the ninth decade of life with no clear variability according to geographical area or seasons of the year.

Chinese guideline for the diagnosis and treatment of Takayasu's arteritis (2023)

Takayasu's arteritis (TAK) is a chronic granulomatous inflammatory disease that involves aorta and its primary branches. It is characterized by wall thickening, stenosis/obliteration or aneurysm formation of the involved arteries. In order to standardize the diagnosis and treatment of TAK in China, a clinical practice guideline with an evidence-based approach is developed under the leadership of National Clinical Medical Research Center for Dermatologic and Immunologic Diseases (NCRC-DID). Eleven recommendations for 11 clinical questions that are important to the diagnosis and treatment of TAK are developed based on the latest evidence and expert opinions combined with real clinical practice in China.

New blood biomarkers and imaging for disease stratification and monitoring of giant cell arteritis

Relapses and late complications remain a concern in giant cell arteritis (GCA). Monitoring strategies are required to effectively tailor treatment and improve patients' outcomes. Current monitoring of GCA is based on clinical assessment and evaluation of traditional inflammatory markers such as C reactive protein and erythrocyte sedimentation rate; however, this approach has limited value in patients receiving interleukin (IL)-6 blocking agents. New blood biomarkers that are less dependent on the IL-6 axis such as IL-23, B cell activating factor, osteopontin and calprotectin have been explored, but none of them has yet accumulated sufficient evidence to qualify as a routine follow-up parameter. Imaging techniques, including ultrasound and 18F-fluorodeoxyglucose positron emission tomography/computed tomography, potentially offer additional insights; however, the choice of the imaging method as well as its interpretation must be investigated further. Future studies are required to investigate the outcome of patients with GCA whose treatment decisions are based on traditional plus novel (laboratory and imaging) biomarkers as compared with those undergoing conventional monitoring strategies.

Effectiveness and safety of a 26-week taper regimen of glucocorticoid in GCA patients: Results from a prospective cohort study

OBJECTIVES

To assess the effectiveness and safety of the 26-week tapering regimen of glucocorticoids (GC) used in the GiACTA trial in a prospective cohort of treatment-naive, biopsy-proven GCA patients.

METHODS

Patients with a new diagnosis of biopsy-proven GCA enrolled in the GC arm of the START project (molecular stratification of patients with GCA to tailor GC and tocilizumab therapy) were included. All patients were treated with the 26-week taper regimen of GC used in the GiACTA trial. The primary endpoint was the rate of relapse-free remission at week 52. The secondary endpoints were the proportion of patients with incident aortic damage, cumulative GC doses and GC-related adverse events (AE).

RESULTS

22 patients were included between December 2018 and February 2022. At week 52, 10 patients (45 %, 95 % CI 24-68) were in relapse-free remission. After a median (IQR) follow-up of 35 (22-40) months, 7 patients (32 %, 95 % CI 14-55) were in relapse-free remission. 18 patients with baseline large-vessel imaging underwent CT angiography at the end of the follow-up. No patients had evidence of new aortic dilation, significant progression of aortic damage or large vessel stenosis. 15/22 patients (68 %) had at least one relapse during follow-up. No patients developed visual or cerebrovascular manifestations during relapses. 15/22 (68 %) patients had at least one GC-related AE.

CONCLUSIONS

A 26 week taper regimen of GC was effective and safe in inducing and maintaining remission in a sizeable proportion of newly diagnosed GCA patients. However, the frequency of GC-related adverse events was high.

Treatment of giant cell arteritis with ultra-short glucocorticoids and tocilizumab: the role of imaging in a prospective observational study

OBJECTIVES

To assess the impact of tocilizumab (TCZ) monotherapy after ultra-short-pulse glucocorticoids (GCs) on clinical manifestations, and vessel inflammation and damage in large vessel-GCA (LV-GCA).

METHODS

In this prospective observational study, we enrolled patients with active LV-GCA. All patients received 500 mg per day i.v. methylprednisolone for three consecutive days and weekly s.c. TCZ injections from day 4 until week 52. PET/CT was performed on all patients at baseline and at weeks 24 and 52. The primary end points were the reduction in the PET vascular activity score (PETVAS) at weeks 24 and 52 compared with baseline, and the proportion of patients with relapse-free remission at weeks 24 and 52. The secondary end point was the proportion of patients with new aortic dilation at weeks 24 and 52.

RESULTS

A total of 18 patients were included (72% female, mean age 68.5 years). Compared with the baseline value, a significant reduction in the PETVAS was observed at weeks 24 and 52, mean (95% CI) reductions -8.6 (-11.5 to -5.7) and -10.4 (-13.6 to -7.2), P = 0.001 and 0.002, respectively. The proportion of patients with relapse-free remission at weeks 24 and 52 was 10/18 (56%, 95% CI 31-78) and 8/17 (47%, 95% CI 23-72), respectively. At weeks 24 and 52, no patient had shown new aortic dilation. However, 4 patients who had shown aortic dilation at baseline showed a significant increase in aortic diameter (≥5 mm) at week 52.

CONCLUSION

TCZ monotherapy after ultra-short-pulse GCs controlled the clinical symptoms of GCA and reduced vascular inflammation.

TRIAL REGISTRATION

ClinicalTrials.gov, https://clinicaltrials.gov, NCT05394909.

Treat-to-target recommendations in giant cell arteritis and polymyalgia rheumatica

OBJECTIVES

To develop treat-to-target (T2T) recommendations in giant cell arteritis (GCA) and polymyalgia rheumatica (PMR).

METHODS

A systematic literature review was conducted to retrieve data on treatment targets and outcomes in GCA/PMR as well as to identify the evidence for the effectiveness of a T2T-based management approach in these diseases. Based on evidence and expert opinion, the task force (29 participants from 10 countries consisting of physicians, a healthcare professional and a patient) developed recommendations, with consensus obtained through voting. The final level of agreement was provided anonymously.

RESULTS

Five overarching principles and six-specific recommendations were formulated. Management of GCA and PMR should be based on shared decisions between patient and physician recognising the need for urgent treatment of GCA to avoid ischaemic complications, and it should aim at maximising health-related quality of life in both diseases. The treatment targets are achievement and maintenance of remission, as well as prevention of tissue ischaemia and vascular damage. Comorbidities need to be considered when assessing disease activity and selecting treatment.

CONCLUSION

These are the first T2T recommendations for GCA and PMR. Treatment targets, as well as strategies to assess, achieve and maintain these targets have been defined. The research agenda highlights the gaps in evidence and the need for future research.

The feasibility of quantitative assessment of dynamic 18F-fluorodeoxyglucose PET in Takayasu's arteritis: a pilot study

PURPOSE

PET has been demonstrated to be sensitive for detecting active inflammation in Takayasu's arteritis (TAK) patients, but semi-quantitative-based assessment may be susceptible to various biological and technical factors. Absolute quantification via dynamic PET (dPET) may provide a more reliable and quantitative assessment of TAK-active arteries. The purpose of this study was to investigate the feasibility and efficacy of dPET in quantifying TAK-active arteries compared to static PET.

MATERIALS AND METHODS

This prospective study enrolled 10 TAK-active patients (fulfilled the NIH criteria) and 5 control participants from March to October 2022. One-hour dPET scan (all TAK and control participants) and delayed static PET scan at 2-h (all TAK patients) were acquired. For 1-h static PET, summed images from 50 to 60 min of the dPET were extracted. PET parameters derived from 1- and 2-h static PET including SUV (SUV1H and SUV2H), target-to-background ratio (TBR) (TBR1H and TBR2H), net influx rate (Ki), and TBRKi extracted from dPET were obtained. The detectability of TAK-active arteries was compared among different scanning methods using the generalized estimating equation (GEE) with a logistic regression with repeated measures, and the GEE with gamma distribution and log link function was used to evaluate the different study groups or scanning methods.

RESULTS

Based on the disease states, 5 cases of TAK were classified as untreated and relapsed, respectively. The SUVmax on 2-h PET was higher than that on 1-h PET in the untreated patients (P < 0.05). However, no significant differences were observed in the median SUVmax between 1-h PET and 2-h PET in the relapsed patients (P > 0.05). The TBRKi was significantly higher than both TBR1H and TBR2H (all P < 0.001). Moreover, the detectability of TAK-active arteries by dPET-derived Ki was significantly higher than 1-h and 2-h PET (all P < 0.001). Significant differences were observed in Kimax, SUVmax-1H, TBR1H, and TBRKi among untreated, relapsed, and control groups (all P < 0.05).

CONCLUSIONS

Absolute quantitative assessment by dPET provides an improved sensitivity and detectability in both visualization and quantification of TAK-active arteries. This elucidates the clinical significance of dPET in the early detection of active inflammation and monitoring recurrence.

Association between the patterns of large-vessel lesions and treatment outcomes in patients with large-vessel giant cell arteritis

OBJECTIVES

We aimed to identify associations between patterns of large-vessel lesions of large-vessel giant cell arteritis (LV-GCA) and treatment outcomes.

METHODS

We extracted data on 68 newly diagnosed patients with LV-GCA from a retrospective, multi-centric, nationwide registry of GCA patients treated with glucocorticoids between 2007 and 2014. Patients with aortic lesions were identified based on the findings from contrast-enhanced computed tomography, magnetic resonance imaging, or positron emission tomography-computed tomography (Group 2, n = 49). Patients without aortic lesions were subdivided into LV-GCA with or without subclavian lesions defined as Group 1 (n = 9) or Group 3 (n = 10), respectively. The primary outcome evaluation was failure to achieve clinical remission by Week 24 and/or relapse within 104 weeks.

RESULTS

The mean age and proportion of patients with cranial lesions and polymyalgia rheumatica in Group 2 were numerically lower than in the other two groups. Large-vessel lesions in Group 3 included carotid, pulmonary, renal, hepatic, or mesenteric lesions. The cumulative rate of poor treatment outcomes >2 years was 11.1%, 55.3%, and 88.0% in Groups 1, 2, and 3, respectively (by Kaplan-Meier analysis). The mean time to poor outcome was significantly different between the groups.

CONCLUSIONS

Classification by subclavian and aortic lesions may be useful to determine treatment strategy.

PET vascular activity score for predicting new angiographic lesions in patients with Takayasu arteritis: a Chinese cohort study

OBJECTIVE

To investigate the ability of 18F-fluorodeoxyglucose PET/CT to predict new lesions in Takayasu arteritis.

METHODS

Eighty-two Chinese patients with newly diagnosed Takayasu arteritis were recruited. Their clinical characteristics, serum biomarkers and imaging results were recorded at baseline and every visit. They were followed up for at least 2 years. New angiographic lesions were evaluated by magnetic resonance angiography. Baseline PET vascular activity scores (PETVAS) for predicting new lesions were evaluated.

RESULTS

At baseline, a moderate correlation was observed between PETVAS and ESR (r = 0.74, P < 0.01) and CRP level (r = 0.69, P < 0.01). Overall, 18 (22%) patients showed new lesions on imaging during a median follow-up time of 36 months. The median time to the first occurrence of new lesions was 18 months. Compared with patients without new lesions, the patients with new lesions included more female patients (67.2% vs 94.4%, P = 0.03), patients with higher ESR values (20 vs 49, P = 0.02) and patients with active disease (62.5% vs 94.4%, P < 0.01). Multivariate Cox regression analysis revealed PETVAS was an independent risk factor for new angiographic lesions (PETVAS ≥8, hazard ratio = 7.56; 95% CI 2.20, 26.01, P < 0.01) with adjustment of age, sex, chest pain, ESR and Physician Global Assessment. Furthermore, patients with PETVAS ≥8 at baseline were more likely to experience adverse events including arterial ischaemic events during the follow-up.

CONCLUSION

PETVAS showed good performance in predicting new lesions in Takayasu arteritis.

Positron Emission Computed Tomography Spectrum of Large Vessel Vasculitis in a Tertiary Center: Differences in 18F-fluorodeoxyglucose Uptake between Large Vessel Vasculitis with Predominant Cranial and Extracranial Giant Cell Arteritis Phenotypes

(1) Objective:To assess the spectrum of PET-CT-related large vessel vasculitis (LVV) in a Spanish tertiary center and to determine whether FDG uptake by PET-CT differs between giant cell arteritis (GCA) with predominant cranial or extracranial phenotypes. (2) Methods: The spectrum of patients diagnosed with LVV by PET-CT in a tertiary referral hospital that cares for 450,000 people over a period of two years was reviewed. Moreover, differences in FDG uptake between LVV-GCA with predominantly cranial and extracranial phenotype were analyzed. (3) Results: Eighty patients were diagnosed with LVV by PET-CT. Most were due to systemic vasculitis (n = 64; 80%), especially GCA (n = 54; 67.5%). Other conditions included the presence of rheumatic diseases (n = 4; 3.2%), tumors (n = 9; 7.2%) and infections (n = 3; 2.4%). LVV-GCA patients with predominant extracranial GCA phenotype were younger (mean ± SD: 68.07 ± 9.91 vs. 75.46 ± 7.64 years; p = 0.017) and had a longer delay to the diagnosis (median [interquartile range] 12 [4-18] vs. 4 [3-8]; p = 0.006), but had polymyalgia rheumatica symptoms more frequently than those with predominantly cranial GCA phenotype (46.3% vs. 15.4%, p = 0.057). When FDG uptake was compared according to the two different disease patterns, no statistically significant differences were observed. However, patients with extracranial LVV-GCA showed a non-significantly higher frequency of vasculitic involvement of lower-extremity arteries. (4) Conclusions: Regardless of the predominant phenotype, LVV identified by PET-CT is more commonly due to GCA in the Spanish population. In these GCA patients, younger age, PMR, and a higher frequency of lower-extremity artery vasculitis suggest the presence of LVV.

PET-Derived Increased Inflammation in Large Vessels is linked to Relapse-Free Survival in Patients with Giant Cell Arteritis

BACKGROUND

 Despite anti-inflammatory treatment, patients with giant cell arteritis (GCA) experience relapse. We aimed to determine respective relapse predictors focusing on [18F]fluorodeoxyglucose ([18F]FDG)-PET-based parameters.

MATERIAL AND METHODS

 21 therapy-naïve GCA patients received [18F]FDG-PET/CT. Patients were divided in two groups: those who relapsed during course of disease and those who did not. Median follow up was 15 months. [18F]FDG-PET/CT was analyzed for visual (PET vascular activity score [VAS]) and quantitative parameters, including Target-to-background-Ratio with liver (TBRliver) and jugular vein (TBRjv) serving as reference tissues. In addition, clinical parameters were tested.

RESULTS

 8/21 (38.1 %) had relapse. Clinical parameters could not significantly discriminate between relapse vs no-relapse, including age (p = 0.9) or blood-based inflammatory markers (white blood cell counts [WBC] and c-reactive protein [CRP], p = 0.72, each). PETVAS score could also not differentiate between respective subgroups (p = 0.59). In a quantitative assessment, TBRjv demonstrated a trend towards significance (p = 0.28). TBRliver, however, separated between patients with and without relapse (p = 0.03).

CONCLUSION

 [18F]FDG PET quantification of vessels may be useful to identify GCA patients prone to relapse during follow-up.

The Role of Imaging in Diagnosis and Monitoring of Large Vessel Vasculitis

Technological advances and increased recognition of the prevalence and implications of large vessel vasculitis have led to robust research into various imaging techniques. Although there is still debate about which modality to choose in specific clinical scenarios, Ultrasound, PET/CT, MRI/A, and CT/A offer complementary information regarding diagnosis, disease activity, and vascular complication monitoring. Recognition of the strengths and limitations of each technique is important for appropriate application in clinical practice.

An exploration of the feasibility and clinical value of half-dose 5-h total-body 18F-FDG PET/CT scan in patients with Takayasu arteritis

PURPOSE

To explore the feasibility and clinical value of 5-h delayed 18F-fluorodeoxyglucose (18F-FDG) total-body (TB) positron emission tomography/computed tomography (PET/CT) in patients with Takayasu arteritis (TA).

METHODS

This study included nine healthy volunteers who underwent 1-, 2.5-, and 5-h triple-time TB PET/CT scans and 55 patients with TA who underwent 2- and 5-h dual-time TB PET/CT scans with 1.85 MBq/kg 18F-FDG. The liver, blood pool, and gluteus maximus muscle signal-to-noise ratios (SNRs) were calculated by dividing the SUVmean by its standard deviation to evaluate imaging quality. TA lesions' 18F-FDG uptake was graded on a three-point scale (I, II, III), with grades II and III considered positive lesions. Lesion-to-blood maximum standardised uptake value (SUVmax) ratio (LBR) was calculated by dividing the lesion SUVmax by the blood pool SUVmax.

RESULTS

The liver, blood pool, and muscle SNR of the healthy volunteers at 2.5- and 5-h were similar (0.117 and 0.115, respectively, p = 0.095). We detected 415 TA lesions in 39 patients with active TA. The average 2- and 5-h scan LBRs were 3.67 and 7.59, respectively (p < 0.001). Similar TA lesion detection rates were noted in the 2-h (92.0%; 382/415) and 5-h (94.2%; 391/415) scans (p = 0.140). We detected 143 TA lesions in 19 patients with inactive TA. The 2- and 5-h scan LBRs were 2.99 and 5.71, respectively (p < 0.001). Similar positive detection rates in inactive TA were noted in the 2-h (97.9%; 140/143) and 5-h (98.6%; 141/143) scans (p = 0.500).

CONCLUSION

The 2- and 5-h 18F-FDG TB PET/CT scans had similar positive detection rates, but both combined could better detect inflammatory lesions in patients with TA.

Pathophysiology, Diagnosis, and Management of Takayasu Arteritis: A Review of Current Advances

Takayasu arteritis (TA) is a rare, chronic, inflammatory vasculitis that primarily affects large arteries, causing significant morbidity and mortality. This review provides an overview of the pathophysiology, diagnosis, and management of TA based on current advances in the field. TA is characterized by autoimmune-mediated inflammation, vascular remodeling, and endothelial dysfunction. The disease progresses through three stages (active, chronic, and healing phase) each presenting distinct clinical features. Diagnosis of TA can be challenging due to non-specific clinical manifestations and the lack of specific diagnostic tests. Various imaging modalities, such as angiography, ultrasound, and Doppler techniques, play a crucial role in the diagnosis of TA by visualizing arterial involvement and assessing disease extent. Management of TA involves a multidisciplinary approach, with disease-modifying anti-rheumatic drugs (DMARDs) as the cornerstone of medical therapy. Synthetic and biologic DMARDs are used to induce remission, control inflammation, and prevent complications. Non-pharmacologic interventions, such as resistance exercises and curcumin supplementation, show potential benefits. Invasive interventions, including endovascular therapy and open surgery, are used for managing vascular lesions. However, challenges remain in disease understanding and management, including the heterogeneity of disease presentation and the lack of standardized treatment guidelines. The future of TA management lies in precision medicine, utilizing biomarkers and molecular profiling to personalize treatment approaches and improve patient outcomes. Further research is needed to unravel the underlying mechanisms of TA and develop targeted therapies.

Giant cell arteritis with vertebral artery involvement-baseline characteristics and follow-up of a monocentric patient cohort

Vertebral artery (VA) involvement in giant cell arteritis (GCA) has rarely been reported. We aimed to evaluate the prevalence, patients' characteristics, and immunotherapies used in patients with GCA and VA involvement at diagnosis and 1 year follow-up, retrospectively including patients being diagnosed between January 2011 and March 2021 in our department. Clinical features, laboratory data, VA imaging, immunotherapy, and 1 year follow-up data were analyzed. Baseline characteristics were compared to GCA patients without VA involvement. Among all 77 cases with GCA, 29 patients (37.7%) had VA involvement, as diagnosed by imaging and/or clinical signs and symptoms. Gender distribution and erythrocyte sedimentation rate (ESR) were significantly different in the groups with and without VA involvement, with more women being affected (38/48 patients, 79.2%) and a significantly higher median ESR in patients without VA involvement (62 vs. 46 mm/h; p = 0.012). MRI and/or CT showed vertebrobasilar stroke at GCA diagnosis in 11 cases. 67/77 patients (87.0%) received high-dose intravenous glucocorticosteroids (GCs) at diagnosis, followed by oral tapering. Six patients were treated with methotrexate (MTX), one with rituximab, and five with tocilizumab (TCZ). 2/5 TCZ patients achieved clinical remission after 1 year, vertebrobasilar stroke within the first year occurred in 2/5 patients. Diagnosis of VA involvement might be underrecognized in GCA patients. VA imaging should be performed in elderly patients with vertebrobasilar stroke presenting with GCA symptoms, not to miss GCA as the etiology of stroke. Efficacy of immunotherapies in GCA with VA affection and long-term outcomes need to be investigated further.

Disease stratification in GCA and PMR: state of the art and future perspectives

Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are closely related conditions characterized by systemic inflammation, a predominant IL-6 signature, an excellent response to glucocorticoids, a tendency to a chronic and relapsing course, and older age of the affected population. This Review highlights the emerging view that these diseases should be approached as linked conditions, unified under the term GCA-PMR spectrum disease (GPSD). In addition, GCA and PMR should be seen as non-monolithic conditions, with different risks of developing acute ischaemic complications and chronic vascular and tissue damage, different responses to available therapies and disparate relapse rates. A comprehensive stratification strategy for GPSD, guided by clinical findings, imaging and laboratory data, facilitates appropriate therapy and cost-effective use of health-economic resources. Patients presenting with predominant cranial symptoms and vascular involvement, who usually have a borderline elevation of inflammatory markers, are at an increased risk of sight loss in early disease but have fewer relapses in the long term, whereas the opposite is observed in patients with predominant large-vessel vasculitis. How the involvement of peripheral joint structures affects disease outcomes remains uncertain and understudied. In the future, all cases of new-onset GPSD should undergo early disease stratification, with their management adapted accordingly.

The role of PET/CT in disease activity assessment in patients with large vessel vasculitis

PURPOSE OF REVIEW

The aim of this article was to review the recent contributions on the role of PET in assessing disease activity in patients with large-vessel vasculitis (giant cell arteritis and Takayasu arteritis).

RECENT FINDINGS

18 FDG (fluorodeoxyglucose) vascular uptake in large-vessel vasculitis at PET shows moderate correlation with clinical indices, laboratory markers and signs of arterial involvement at morphological imaging. Limited data may suggest that 18 FDG (fluorodeoxyglucose) vascular uptake could predict relapses and (in Takayasu arteritis) the development of new angiographic vascular lesions. PET appears to be in general sensitive to change after treatment.

SUMMARY

While the role of PET in diagnosis large-vessel vasculitis is established, its role in evaluating disease activity is less clear-cut. PET may be used as an ancillary technique, but a comprehensive assessment, including clinical, laboratory and morphological imaging is still required to monitor patients with large-vessel vasculitis over time.

Tocilizumab in giant cell arteritis: an update for the clinician

PURPOSE OF REVIEW

The recent approval of tocilizumab (TCZ) for the treatment of giant cell arteritis (GCA) has changed the landscape for management of this disease. Herein, we review recent literature addressing practical questions for the clinician regarding the use of TCZ in GCA. We evaluate efficacy of TCZ across different disease phenotypes, optimal dosing and formulation, treatment-related toxicity, recommendations for monitoring disease, and duration of therapy.

RECENT FINDINGS

Post-hoc analyses of a large clinical trial and real-world data suggest efficacy of TCZ across various disease phenotypes in GCA, and support use of weekly subcutaneous dosing over every-other-week dosing. More data are needed to guide duration of TCZ therapy, optimal disease activity monitoring in patients treated with TCZ, and to speak to efficacy in GCA with large vessel involvement.

SUMMARY

TCZ has added valuably to the treatment arsenal in GCA, though more data are needed to guide optimal use of the drug.

Metabolic inflammatory volume and total inflammatory glycolysis: novel parameters to evaluate PET-CT disease activity in Takayasu arteritis

OBJECTIVES

To evaluate diagnostic accuracy for active Takayasu arteritis (TAK) for two novel ¹⁸F-fluorodeoxyglucose PET-CT parameters, the inflammatory volume (MIV) and total inflammatory glycolysis (TIG), to quantitate volume of metabolically-active arterial tissue.

METHODS

From a cohort of TAK (n = 36, 35 immunosuppressive-naïve), images of PET-CTs were reviewed for mean and maximum standardized uptake value (SUV_mean and SUV_max), target-to-blood pool ratio (TBR), target-to-liver ratio (TLR), and PET Vasculitis Activity Score (PETVAS). Regions of interest were drawn to semiautomatically calculate MIV in areas of ¹⁸F-fluorodeoxyglucose uptake ≥ 1.5 SUV_mean after excluding physiological tracer uptake. TIG was calculated by multiplying MIV with SUV_mean. PET-CT parameters, ESR, CRP, and clinical disease activity scores were compared against the gold standard of physician global assessment of disease activity (PGA, active/inactive).

RESULTS

Using dichotomized cut-offs for active TAK at SUV_max (≥ 2.21), SUV_mean (≥ 1.58), TBR (≥ 2.31), TLR (≥ 1.22), PETVAS (various cut-offs), ESR (≥ 40 mm/hour), and CRP (≥ 6 mg/L), the novel indices MIV (≥ 1.8) and TIG (≥ 2.7) performed similar [area under the receiver operating characteristics curve (AUC) 0.873 for both] to SUV_max (AUC 0.841) and SUV_mean (AUC 0.851), and better than TBR (AUC 0.773), TLR (AUC 0.773), PETVAS [≥ 5.5 (AUC 0.750), ≥ 10 (AUC 0.636), ≥ 15 (AUC 0.546)], ESR (AUC 0.748), or CRP (AUC 0.731). MIV and TIG had similar agreement with PGA or CRP as with SUV_max or SUV_mean, and better agreement than TBR, TLR, or PETVAS cut-offs.

CONCLUSIONS

MIV and TIG performed similarly, therefore, are viable alternatives to existing PET-CT parameters to assess TAK disease activity in this preliminary report. Key Points • MIV and TIG performed similar to SUV_max and SUV_max for disease activity assessment in TAK. • MIV and TIG distinguished active TAK better than TBR, TLR, PETVAS cut-offs, ESR, or CRP. • MIV and TIG had better agreement with PGA or CRP than TBR, TLR, or PETVAS cut-offs.

Effectiveness of a two-year tapered course of tocilizumab in patients with giant cell arteritis: A single-centre prospective study

OBJECTIVE

To evaluate the feasibility of tocilizumab tapering and withdrawal in patients with giant cell arteritis (GCA).

METHODS

GCA patients eligible for tocilizumab were prospectively enrolled. Tocilizumab was administered weekly for the first 12 months, every-other-week for an additional 12 months, then discontinued. Relapses on tocilizumab were managed with temporary increases in systemic glucocorticoids or addition of methotrexate. Primary outcome was relapse-free survival at month 6 after tocilizumab suspension. Relapse-free survival on tocilizumab, imaging response, and adverse events were evaluated.

RESULTS

23 GCA patients were enrolled. Reasons for tocilizumab start were relapse (n = 14), persistence of activity (n = 5), or steroid-related adverse events (n = 4). At tocilizumab start, two patients were on methotrexate, which was maintained. Fourteen patients had extracranial vascular involvement on 18FDG-PET/CT. During the first 12 months, four patients (17%) had clinical relapse. At every-other-week tocilizumab start, all patients were in clinical remission, two patients had active vasculitis on 18FDG-PET/CT; two patients were on steroid therapy, and four patients were taking methotrexate. Two patients (9%) relapsed while on every-other-week tocilizumab. At tocilizumab suspension, no patient was on steroid therapy and no patient had signs of active vasculitis on 18FDG-PET/CT. In the 6 months after tocilizumab discontinuation, six patients (26%) relapsed. No new or unexpected safety findings were identified.

CONCLUSION

Tocilizumab tapered over a two-year period was effective to induce and maintain remission in GCA. Relapses on tocilizumab were minor and responded to incremental changes in therapy. A significant proportion of patients relapsed in the 6 months after therapy suspension.

Role of 18F-FDG PET/CT in Large Vessel Vasculitis and Polymyalgia Rheumatica

Systemic vasculitides comprise a group of autoimmune diseases affecting blood vessels, including large vessel vasculitis (LVV) and medium-sized vessel vasculitis such as giant cell arteritis (GCA) and Takayasu arteritis (TAK). GCA frequently overlaps with polymyalgia rheumatica (PMR), a rheumatic inflammatory condition affecting bursae, tendons or tendon sheaths, and joints. ¹⁸F-FDG PET/CT plays an important role in the diagnostic work-up of GCA, PMR, and TAK and is increasingly used to monitor treatment response. This continuing education article provides up-to-date guidance on the role of ¹⁸F-FDG PET/CT in patients with LVV, medium-sized vessel vasculitis, and PMR. It provides a general introduction on the clinical presentation and challenges in the diagnostic work-up of LVV and medium-sized vessel vasculitis, with a focus on the 2 major LVV subtypes: GCA, including PMR, and TAK. Next, practice points to perform and interpret the results of ¹⁸F-FDG PET/CT are described in line with the published procedure recommendations. Furthermore, the diagnostic performance and its role for treatment monitoring are discussed, taking into account recent international recommendations for the use of imaging in LVV and medium-sized vessel vasculitis in clinical practice. This is illustrated by several clinically representative PET/CT scan examples. Lastly, knowledge of limitations and pitfalls is essential to understand the role of ¹⁸F-FDG PET/CT in LVV, medium-sized vessel vasculitis, and PMR. Challenges and opportunities, as well as future research and conclusions, are highlighted. Learning objectives provide up-to-date guidance for the role of ¹⁸F-FDG PET/CT in patients with suspected LVV, medium-sized vessel vasculitis, and PMR.

Controlled supramolecular interactions for targeted release of Amiodarone drug through Graphyne to treat cardiovascular diseases: An in silico study

In the current study, the drug loading ability of graphyne (GY) for the amiodarone (AMD) drug is investigated for the first time. The efficacy of GY as a carrier for amiodarone (a cardiovascular drug) is evaluated by calculating its electronic, energetic, optimized, and excited state properties with help of the density functional theory (DFT). The AMD drug interacted with the GY molecule with an adsorption energy of about -0.19 eV (gas-phase) and -1.92 eV (aqueous phase), suggesting that the AMD@GY complex is stable in water-phase. The HOMO (highest-occupied molecular-orbital) of the AMD@GY complex is concentrated on the AMD drug while the LUMO (lowest-unoccupied molecular-orbital) is centralized on GY with absolute charge separation, indicating charge transfer will occur between AMD and GY. The charge-transfer process is further studied with the aid of charge-decomposition analysis (CDA). The non-covalent interaction analysis (NCI) exposed that non-covalent forces exist between the GY carrier and AMD drug. These non-covalent forces between AMD drug and GY carrier play a significant role in drug unloading at the targeted or diseased site. Likewise, the calculations at excited-state, charge-state (+1 and -1) influence on GY and AMD@GY complex structures, and photo-induced electron transfer analysis (PET) are also studied for the graphyne-based drug-delivery system. According to PET and electron-hole analysis, fluorescence-quenching will occur upon interaction. Overall, it is concluded that graphyne can be exploited as a drug carrier for amiodarone drug delivery. Researchers will be fascinated to look at alternative 2D nanomaterials for drug delivery applications as a result of this theoretical work.

Positron Emission Tomography (PET) Scan as a Diagnostic Tool for Giant Cell Arteritis

Giant cell arteritis (GCA) is an inflammatory vasculitis that typically affects the elderly, preferentially involving large and medium-sized arteries and can potentially cause irreversible loss of vision. Early diagnosis and treatment are necessary to prevent this dreaded complication. Temporal artery biopsy has been the gold standard test in diagnosing GCA, however, false negative results due to presence of skip lesions, restricted inflammation, and early initiation of steroids have limited its diagnostic significance. We report a case of a 67-year-old female with headache, blurry vision, posterior scalp tenderness, feeble left temporal artery pulse on a physical exam with normal inflammatory markers. Temporal artery biopsy showed disruption and reduplication of internal elastic lamina without any evidence of giant cells or inflammatory cells. Owing to high clinical suspicion, fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) was further done which revealed mildly increased uptake in the thoracic aorta, consistent with a diagnosis of large vessel vasculitis.

Imaging of giant cell arteritis - recent advances

Imaging is increasingly being used to guide clinical decision-making in patients with giant cell arteritis (GCA). While ultrasound has been rapidly adopted in fast-track clinics worldwide as an alternative to temporal artery biopsy for the diagnosis of cranial disease, whole-body PET/CT is emerging as a potential gold standard test for establishing large vessel involvement. However, many unanswered questions remain about the optimal approach to imaging in GCA. For example, it is uncertain how best to monitor disease activity, given there is frequent discordance between imaging findings and conventional disease activity measures, and imaging changes typically fail to resolve completely with treatment. This chapter addresses the current body of evidence for the use of imaging modalities in GCA across the spectrum of diagnosis, monitoring disease activity, and long-term surveillance for structural changes of aortic dilatation and aneurysm formation and provides suggestions for future research directions.

Giant cell arteritis successfully treated with subcutaneous tocilizumab monotherapy

Glucocorticoid remains the mainstay for treatment of large vessel vasculitis (LVV) including giant cell arteritis (GCA); however, the disease affects the elderly for whom the adverse effects of glucocorticoid are problematic. Recently, some reports have suggested that intravenous tocilizumab (TCZ) monotherapy is effective for this disease. To date, it remains unknown whether subcutaneous TCZ monotherapy is also effective. Here, we present a first case of GCA successfully treated with subcutaneous TCZ monotherapy. A 75-year-old woman presented with shoulder and hip pain. She was diagnosed with polymyalgia rheumatica (PMR) and treated with low-dose prednisolone (15 mg daily); however, she discontinued glucocorticoid therapy at her discretion due to the psychiatric adverse effect (cognitive dysfunction). Seven months later, her shoulder and hip pain relapsed. Furthermore, ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) revealed uptake in the descending thoracic aorta, indicating a complication of LVV. She refused to take glucocorticoid for fear of psychiatric adverse effects and chose subcutaneous TCZ monotherapy (162 mg weekly) for treating this life-threatening urgent condition. Nine months later, her shoulder and hip pain resolved and FDG-PET/CT demonstrated no uptake in the descending thoracic aorta, indicating a successful treatment with subcutaneous TCZ monotherapy for the disease. No adverse events and disease relapse were found during observation period. Our case and the literature review suggest that not only intravenous injection but also subcutaneous injection of TCZ monotherapy can serve as an alternative treatment for patients with GCA who have comorbidities or refuse to take glucocorticoid.

Advanced molecular imaging in large-vessel vasculitis: Adopting FDG-PET into a clinical workflow

The use of fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging to detect vascular inflammation is increasingly common in the clinical management of patients with large-vessel vasculitis (LVV). In this review, the role of FDG-PET imaging to diagnose and monitor vascular disease activity will be detailed. Suggestions on incorporation of FDG-PET imaging into a clinical workflow will be provided with emphasis on patient preparation, image acquisition, and image interpretation. If FDG-PET imaging is obtained, multimodal imaging assessment, whereby FDG-PET imaging and non-invasive angiography are obtained concurrently, and correlation of imaging findings with clinical assessment is generally advisable. Considering the clinical scenario and treatment status of the patient is important when interpreting vascular FDG-PET image findings.

Update on Imaging of Inflammatory Arthritis and Related Disorders

Arthritis and other rheumatic disorders are very frequent in the general population and responsible for a huge physical and disability burden to affected patients as well as a major cost to the society. Precise evaluation often relies on clinical data only but additional imaging may be required i) for a more objective assessment of the disease status, such as in rheumatoid arthritis (RA) or ankylosing spondyloarthritis (AS), ii) for providing prognostic information and evaluating response to treatment or iii) for establishing diagnosis, in patients with unclear clinical picture, such as polymyalgia rheumatica (PMR) and large-vessel vasculitis (LVV). Besides radiological techniques (x-rays, ultrasound, and MRI), functional and molecular imaging has emerged as a valid tool for this purpose in several disorders. Bone scanning has long been a method of choice but is now more used as a triage tool in patients with unclear complaints, including degenerative disorders (eg osteoarthritis). ¹⁸F-FDG-PET/CT (FDG) proved efficient in assessing the extent of the disease and response to treatment in RA and related disorders, and to provide accurate diagnosis in some systemic disorders, including PMR and LVV. Based on glucose metabolism, FDG-PET/CT is able to show increased metabolism in peripheral cells involved in inflammation (eg neutrophils, lymphocytes or monocytes/macrophages) but also in fibroblasts that proliferate in the pannus. The lack of specificity of FDG is a limitation and many alternative tracers were developed at the preclinical stage or applied in the clinics, especially within clinical trials. They include imaging of macrophages using translocator protein (TSPO), folate-receptors or other targets on activated cells. These new tools will undoubtedly become more and more available in the everyday clinical workup of patients with rheumatisms. Finally, it should be kept in mind that a very simple tracer, ¹⁸F-fluoride is widely more performant in AS than FDG.

What is a response in randomised controlled trials in giant cell arteritis?

Glucocorticoids (GCs) are the gold standard for treatment of giant cell arteritis (GCA); however, there is a need for studies on GC-sparing agents, given that up to 85% of patients receiving GC only develop adverse events. Previous randomised controlled trials (RCTs) have applied different primary endpoints, limiting the comparison of treatment effects in meta-analyses and creating an undesired heterogeneity of outcomes. The harmonisation of response assessment is therefore an important unmet need in GCA research. In this viewpoint article, we discuss the challenges and opportunities with the development of new, internationally accepted response criteria. A change of disease activity is a fundamental component of response; however, it is debatable whether the ability to taper GC and/or the maintenance of a disease state for a specific time period, as applied in recent RCTs, should be part of response assessment. The role of imaging and novel laboratory biomarkers as possible objective markers of disease activity needs further investigation but might be a possibility when drugs directly or indirectly influence the levels of traditional acute-phase reactants such as erythrocyte sedimentation rate and C reactive protein. Futures response criteria might be constructed as a multidomain set, but the questions about which domains will be included and what their relative weights will be still need to be answered.

An Automated Method for Artifical Intelligence Assisted Diagnosis of Active Aortitis Using Radiomic Analysis of FDG PET-CT Images

The aim of this study was to develop and validate an automated pipeline that could assist the diagnosis of active aortitis using radiomic imaging biomarkers derived from [18F]-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography (FDG PET-CT) images. The aorta was automatically segmented by convolutional neural network (CNN) on FDG PET-CT of aortitis and control patients. The FDG PET-CT dataset was split into training (43 aortitis:21 control), test (12 aortitis:5 control) and validation (24 aortitis:14 control) cohorts. Radiomic features (RF), including SUV metrics, were extracted from the segmented data and harmonized. Three radiomic fingerprints were constructed: A-RFs with high diagnostic utility removing highly correlated RFs; B used principal component analysis (PCA); C-Random Forest intrinsic feature selection. The diagnostic utility was evaluated with accuracy and area under the receiver operating characteristic curve (AUC). Several RFs and Fingerprints had high AUC values (AUC > 0.8), confirmed by balanced accuracy, across training, test and external validation datasets. Good diagnostic performance achieved across several multi-centre datasets suggests that a radiomic pipeline can be generalizable. These findings could be used to build an automated clinical decision tool to facilitate objective and standardized assessment regardless of observer experience.

Monocyte subsets and monocyte-related chemokines in Takayasu arteritis

The pathogenesis of Takayasu arteritis (TAK) is poorly understood and no previous studies have analyzed monocytes in TAK. This study evaluated monocyte subsets and monocyte-related chemokines in the peripheral blood of TAK patients and healthy controls (HC). Monocyte subsets were identified as classical (CD14⁺CD16^-), intermediate (CD14⁺CD16^dim), and non-classical (CD14^dimCD16^high) in the peripheral blood. The chemokines CCL (C-C chemokine ligand)2, CCL3, CCL4, CCL5, CCL7, CXCL (C-X-C motif ligand)10, and CX3CL (C-X3-C motif ligand)1 were measured in the sera. Thirty-two TAK patients and 30 HC were evaluated. Intermediate monocytes were higher in TAK than HC [25.0 cells ×10⁶/L (16.7-52.0) vs. 17.2 cells ×10⁶/L (9.2-25.3); p = 0.014]. Active disease was associated with monocytosis (p = 0.004), increased classical (p = 0.003), and intermediate (p < 0.001) subsets than HC. Prednisone reduced the percentage of non-classical monocytes (p = 0.011). TAK patients had lower CCL3 (p = 0.033) and CCL4 (p = 0.023) levels than HC, whereas CCL22 levels were higher in active TAK compared to the remission state (p = 0.008). Glucocorticoids were associated with lower CXCL10 levels (p = 0.012). In TAK, CCL4 correlated with total (Rho = 0.489; p = 0.005), classical and intermediate monocytes (Rho = 0.448; p = 0.010 and Rho = 0.412; p = 0.019). In conclusion, TAK is associated with altered counts of monocyte subsets in the peripheral blood compared to HC and CCL22 is the chemokine with the strongest association with active disease in TAK.

Positron Emission Tomography Imaging in Vasculitis

Systemic vasculitides comprise a group of autoimmune diseases affecting blood vessels. [18F]-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (FDG-PET/CT) plays an important role in the diagnosis and therapeutic monitoring of vasculitides affecting large-sized and medium-sized vessels. FDG-PET/CT also provides complementary information to other vascular imaging tools. The resolution and sensitivity of newer generation scanners continues to increase, hereby improving the ability of FDG-PET/CT to accurately assess the full disease extent in patients with vasculitis. Novel tracers targeting specific immune cells will allow for more detailed detection of vascular infiltrates.

Time-related aortic inflammatory response, as assessed with 18F-FDG PET/CT, in patients hospitalized with severely or critical COVID-19: the COVAIR study

AIM

Arterial involvement has been implicated in the coronavirus disease of 2019 (COVID-19). Fluorine 18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) imaging is a valuable tool for the assessment of aortic inflammation and is a predictor of outcome. We sought to prospectively assess the presence of aortic inflammation and its time-dependent trend in patients with COVID-19.

METHODS

Between November 2020 and May 2021, in this pilot, case-control study, we recruited 20 patients with severe or critical COVID-19 (mean age of 59 ± 12 years), while 10 age and sex-matched individuals served as the control group. Aortic inflammation was assessed by measuring 18F-FDG uptake in PET/CT performed 20-120 days post-admission. Global aortic target to background ratio (GLA-TBR) was calculated as the sum of TBRs of ascending and descending aorta, aortic arch, and abdominal aorta divided by 4. Index aortic segment TBR (IAS-TBR) was designated as the aortic segment with the highest TBR.

RESULTS

There was no significant difference in aortic 18F-FDG PET/CT uptake between patients and controls (GLA-TBR: 1.46 [1.40-1.57] vs. 1.43 [1.32-1.70], respectively, P = 0.422 and IAS-TBR: 1.60 [1.50-1.67] vs. 1.50 [1.42-1.61], respectively, P = 0.155). There was a moderate correlation between aortic TBR values (both GLA and IAS) and time distance from admission to 18F-FDG PET-CT scan (Spearman's rho = - 0.528, P = 0.017 and Spearman's rho = - 0.480, p = 0.032, respectively). Patients who were scanned less than or equal to 60 days from admission (n = 11) had significantly higher GLA-TBR values compared to patients that were examined more than 60 days post-admission (GLA-TBR: 1.53 [1.42-1.60] vs. 1.40 [1.33-1.45], respectively, P = 0.016 and IAS-TBR: 1.64 [1.51-1.74] vs. 1.52 [1.46-1.60], respectively, P = 0.038). There was a significant difference in IAS- TBR between patients scanned ≤ 60 days and controls (1.64 [1.51-1.74] vs. 1.50 [1.41-1.61], P = 0.036).

CONCLUSION

This is the first study suggesting that aortic inflammation, as assessed by 18F-FDG PET/CT imaging, is increased in the early post COVID phase in patients with severe or critical COVID-19 and largely resolves over time. Our findings may have important implications for the understanding of the course of the disease and for improving our preventive and therapeutic strategies.

Somatostatin Receptor PET/MR Imaging of Inflammation in Patients With Large Vessel Vasculitis and Atherosclerosis

BACKGROUND

Assessing inflammatory disease activity in large vessel vasculitis (LVV) can be challenging by conventional measures.

OBJECTIVES

We aimed to investigate somatostatin receptor 2 (SST2) as a novel inflammation-specific molecular imaging target in LVV.

METHODS

In a prospective, observational cohort study, in vivo arterial SST2 expression was assessed by positron emission tomography/magnetic resonance imaging (PET/MRI) using 68Ga-DOTATATE and 18F-FET-βAG-TOCA. Ex vivo mapping of the imaging target was performed using immunofluorescence microscopy; imaging mass cytometry; and bulk, single-cell, and single-nucleus RNA sequencing.

RESULTS

Sixty-one participants (LVV: n = 27; recent atherosclerotic myocardial infarction of ≤2 weeks: n = 25; control subjects with an oncologic indication for imaging: n = 9) were included. Index vessel SST2 maximum tissue-to-blood ratio was 61.8% (P < 0.0001) higher in active/grumbling LVV than inactive LVV and 34.6% (P = 0.0002) higher than myocardial infarction, with good diagnostic accuracy (area under the curve: ≥0.86; P < 0.001 for both). Arterial SST2 signal was not elevated in any of the control subjects. SST2 PET/MRI was generally consistent with 18F-fluorodeoxyglucose PET/computed tomography imaging in LVV patients with contemporaneous clinical scans but with very low background signal in the brain and heart, allowing for unimpeded assessment of nearby coronary, myocardial, and intracranial artery involvement. Clinically effective treatment for LVV was associated with a 0.49 ± 0.24 (standard error of the mean [SEM]) (P = 0.04; 22.3%) reduction in the SST2 maximum tissue-to-blood ratio after 9.3 ± 3.2 months. SST2 expression was localized to macrophages, pericytes, and perivascular adipocytes in vasculitis specimens, with specific receptor binding confirmed by autoradiography. SSTR2-expressing macrophages coexpressed proinflammatory markers.

CONCLUSIONS

SST2 PET/MRI holds major promise for diagnosis and therapeutic monitoring in LVV. (PET Imaging of Giant Cell and Takayasu Arteritis [PITA], NCT04071691; Residual Inflammation and Plaque Progression Long-Term Evaluation [RIPPLE], NCT04073810).

18-Fluorodeoxyglucose positron emission tomography/computed tomography for large vessel vasculitis in clinical practice

Diagnosis, prognostic assessment, and monitoring disease activity in patients with large vessel vasculitis (LVV) can be challenging. Early recognition of LVV and treatment adaptation is essential because vascular complications (aneurysm, dilatations, ischemic complications) or treatment related side effects can occur frequently in these patients. 18-fluorodeoxyglucose positron emission tomography/computed tomography (2-[18F]FDG-PET/CT) is increasingly used to diagnose, follow, and evaluate treatment response in LVV. In this review, we aimed to summarize the current evidence on the value of 2-[18F]FDG-PET/CT for diagnosis, follow, and treatment monitoring in LVV.

Multimodality imaging of large-vessel vasculitis

Multimodality cardiovascular imaging is an essential component of the clinical management of patients with large-vessel vasculitis (LVV), a chronic, relapsing and remitting inflammatory disease of the aorta and its major branches. Imaging is needed to confirm the initial diagnosis, to survey the extent and severity of arterial involvement, to screen for cardiovascular complications and for subsequent long-term disease monitoring. Indeed, diagnosing LVV can be challenging due to the non-specific nature of the presenting symptoms, which often evoke a broad differential. Identification of disease flares and persistent residual arteritis following conventional treatments for LVV present additional clinical challenges. However, by identifying and tracking arterial inflammation and injury, multimodality imaging can help direct the use of disease-modifying treatments that suppress inflammation and prevent or slow disease progression. Each of the non-invasive imaging modalities can provide unique and complementary information, contributing to different aspects of the overall clinical assessment. This article provides a focused review of the many roles of multimodality imaging in LVV.

Differentiation of lower limb vasculitis from physiological uptake on FDG PET/CT imaging

PURPOSES

To analyze the difference of 2-deoxy-2-[¹⁸F]fluoro-D-glucose (¹⁸F-FDG) uptake between vasculitis and non-vasculitic patients in PET/CT imaging and the factors related to vascular uptake in non-vasculitic patients. To investigate the feasibility of identifying vasculitis of the lower limb and physiological uptake with delayed imaging.

PROCEDURES

Among 244 patients who underwent PET/CT examination, imaging features of patients with or without vasculitis were retrospectively analyzed. The factors related to FDG uptake in the lower limb vessels of non-vasculitic patients were analyzed. Another 44 patients with suspected systemic vasculitis in PET/CT were prospectively studied to analyze the efficacy of delayed imaging on differentiating vascular uptake in lower limbs.

RESULTS

In PET/CT imaging of patients with vasculitis, involvement of trunk vessels showed segmental or diffuse FDG distribution. Lower limb vascular involvement showed reticular uptake accompanied by nodular or patchy changes. In non-vasculitic patients, vascular uptake mainly showed linear uptake in lower limb vessels and there was no significant difference in uptake degree compared with vasculitis patients. Body weight and interval time were the independent influence factors of vascular uptake in lower limbs of non-vasculitic patients. In delayed imaging, lower limb vasculitis all showed reticular uptake and physiological uptake all showed a linear pattern. ROC analysis showed the change rate of SUV_max (≥ 20%) between early and delayed imaging could delineate physiological vascular uptake with a sensitivity of 100% and specificity of 81.0%.

CONCLUSIONS

When PET/CT is used for the diagnosis and classification of vasculitis, the physiological uptake of lower limb vessels may mislead the diagnosis. PET/CT imaging features or delayed imaging improved diagnostic efficacy.

Delayed contrast-enhanced magnetic resonance imaging enables detection of pulmonary artery lesions in Takayasu's arteritis

Background

Delayed contrast-enhanced magnetic resonance imaging (DE-MRI) is a useful technique to identify arterial wall inflammation. The aim of this study was to explore the value of DE-MRI in the evaluation of pulmonary artery (PA) lesions in Takayasu's arteritis (TAK) compared with ¹⁸F-fuorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT).

Methods

Patients with TAK were recruited for this prospective, observational study. Imaging and clinical assessments were performed concurrently. Only thoracic arteries were evaluated, and they were divided into 18 segments per person. All arterial lesions were evaluated using both PET/CT and DE-MRI. Correlations between both methods were assessed in the PA and thoracic aorta. A receiver operating characteristic (ROC) curve was used to analyze the value of imaging features in detecting disease activity based on National Institutes of Health (NIH) criteria.

Results

A total of 24 patients contributed 432 arterial segments. Using PET/CT, correlations between arterial wall DE, thickening, and edema in the PA were 84.52%, 67.92%, and 58.33%, respectively, with Cohen's kappa =0.69, 0.30, and 0.13, respectively; for the thoracic aorta, the values were 86.38%, 80.00%, and 75.92%, respectively, with Cohen's kappa =0.71, 0.52, and 0.372, respectively. There was a significant difference in the incidence of wall DE between the PA and thoracic aorta in patients with clinically active TAK (χ²=6.85, P=0.009). DE-MRI presented a higher area under the curve [area under the curve (AUC); 0.729, P=0.047] than wall thickening and edema in the detection of TAK activity. The wall DE combined with erythrocyte sedimentation rate (ESR) showed improved efficiency (AUC: 0.858, P=0.003).

Conclusions

DE-MRI displays appreciable correlations with PET/CT findings and allows for the detection of PA inflammation in patients with TAK; it shows higher values in the thoracic aorta than in the PA. The combination of wall DE and ESR can improve the efficiency of assessing disease status.