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

Imaging Challenges and Developments in Large-vessel Vasculitis

Vascular imaging is an integral part of large-vessel vasculitis (LVV) evaluation and management. Several imaging modalities are currently employed in clinical practice including vascular ultrasound, computed tomography angiography, MRI and magnetic resonance angiography, and 18F-fluorodeoxyglucose PET. Well-established roles for imaging in LVV include disease diagnosis and assessment of luminal lesions reflecting vascular damage. The ability of imaging to determine treatment response, monitor disease activity, and predict future arterial damage is an area of active research.

FDG PET/CT in large vessel vasculitis

Large vessel vasculitides (LVV) such as giant cell arteritis, Takayasu arteritis and aortitis/periaortitis are characterised by immune-mediated inflammation of medium to large arteries. Clinical disease manifestations can be non-specific and diagnostic imaging plays an important role in the diagnostic pathway. In recent years, FDG PET/CT has proven to be a powerful metabolic tool that can provide a wholed body, non-invasive assessment of vascular inflammation. This review outlines the clinical features of large vessel vasculitis and the closely related entity of polymyalgia rheumatica, summarises the evidence for FDG PET/CT in the assessment of these conditions, and provides guidance for patient preparation, image acquisition and interpretation.

Hybrid cardiovascular imaging. A clinical consensus statement of the european association of nuclear medicine (EANM) and the european association of cardiovascular imaging (EACVI) of the ESC

Hybrid imaging consists of a combination of two or more imaging modalities, which equally contribute to image information. To date, hybrid cardiovascular imaging can be performed by either merging images acquired on different scanners, or with truly hybrid PET/CT and PET/MR scanners. The European Association of Nuclear Medicine (EANM), and the European Association of Cardiovascular Imaging (EACVI) of the European Society of Cardiology (ESC) aim to review clinical situations that may benefit from the use of hybrid cardiac imaging and provide advice on acquisition protocols providing the most relevant information to reach diagnosis in various clinical situations.

18F-FDG-PET/CT Scan for Detection of Large Vessel Involvement in Giant Cell Arteritis: Arteser Spanish Registry

Background/Objectives: Imaging studies have transformed the diagnosis of large vessel vasculitis (LVV) involvement in giant cell arteritis (GCA). A positron emission tomography/computed tomography (PET/CT) scan with 18-fluorodeoxyglucose (18F-FDG) has emerged as a valuable tool for assessing LVV. We aimed to determine the utility of an 18F-FDG-PET/CT scan in detecting LVV in GCA in the ARTESER registry. Methods: The ARTESER study is a large multicenter, retrospective, longitudinal, and observational study, promoted by the Spanish Society of Rheumatology. It included patients newly diagnosed with GCA across 26 tertiary hospitals from 1 June 2013 to 29 March 2019. Patients with a diagnosis of incidental GCA were included if they fulfilled specific criteria, including the ACR 1990 criteria, positive imaging examinations, or the expert clinical opinion of investigators. Differences between patients with positive and negative 18F-FDG-PET/CT scan results were analyzed using a bivariate model. A regression model assessed associations in patients with a positive scan, and the predictive capacity of the cumulative dose of glucocorticoids (GC) on PET scan outcomes was evaluated using ROC curve analysis. Results: Out of 1675 GCA patients included in the registry, 377 met the inclusion criteria of having an 18F-FDG-PET/CT scan. The majority were diagnosed with a cranial GCA phenotype, and 65% had LVV. The thoracic aorta was the most frequently affected. Cardiovascular disease, diabetes, and older age had a negative association with a positive scan outcome. The OR for having a positive 18F-FDG-PET/CTC scan was lower as the number of days increased. Depending on the cumulative dosage of the GC, the 18F-FDG-PET/CT scan showed an AUC of 0.74, with a Youden index > 60 mg/day. Conclusions: Younger patients showed a higher probability of presenting LVV as detected by the 18F-FDG-PET/CT scan. The timing of the examination and the cumulative dosage of the GC influenced the likelihood of a positive result, with earlier tests being more likely to detect inflammation.

An overview of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in giant cell arteritis

PET/CT is an imaging modality that is increasingly being used to diagnose large-vessel vasculitis. In the case of giant cell arteritis, it was first used to demonstrate inflammation of the walls of large arterial trunks such as the aorta and its main branches, showing that aortic involvement is common in this vasculitis and associated with the occurrence of aortic complications such as aneurysms. More recently, with the advent of digital PET/CT, study of the cranial arteries (i.e., temporal, occipital, maxillary and vertebral arteries) has become possible, further increasing the diagnostic interest of this examination for the diagnosis of GCA. Despite these advantages, there are still limitations and questions regarding the use of PET/CT for the diagnosis and especially the follow-up of GCA. The aim of this review is to take stock of currently available data on the use of PET/CT for GCA diagnosis and follow-up.

18F-Fluoride PET/CT-Updates

Sodium Fluoride-18 production started in the 1940s and was described clinically for the first time in 1962 as a bone-imaging agent. However, its use became dormant with the development of conventional bone scintigraphy, especially due to its low cost. Conventional bone scintigraphy has been the most utilized Nuclear Medicine technique for identifying osteoblastic bone metastases, especially in prostate and breast cancers for decades and is also employed to identify benign bone disease, especially in the orthopedic setting. While bone scintigraphy is highly sensitive, it lacks adequate specificity. With the advent of high-quality 3D Whole-Body Positron Emission Tomography combined with computed tomography (PET/CT), images, Sodium Fluoride-18 imaging with PET/CT (Fluoride PET/CT) re-emerged. This PET/CT bone-imaging agent provides higher sensitivity and specificity to detect bone lesions in both the oncological scenario as well as to identify benign bone and joint disorders. PET/CT bone-imaging provides a precise view of the bone metabolism remodeling processes at a molecular level, throughout the skeleton, and combines anatomical information, enhancing diagnostic specificity and accuracy. This article review will explore the updates on clinical applications of Fluoride PET/CT in oncology and benign conditions encompassing orthopedic, inflammatory and cardiovascular conditions and treatment response assessment.

EANM/SNMMI guideline/procedure standard for [18F]FDG hybrid PET use in infection and inflammation in adults v2.0

INTRODUCTION

Hybrid [18F]FDG PET imaging is currently the method of choice for a wide variety of infectious and inflammatory disorders and was recently adopted in several clinical guidelines. A large amount of evidence-based articles, guidelines and appropriate use criteria have been published since the first version of this guideline in 2013.

PURPOSE

To provide updated evidence-based information to assist physicians in recommending, performing and interpreting hybrid [18F]FDG PET examinations for infectious and inflammatory disorders in the adult population.

METHODS

A systematic literature search of evidence-based articles using whole-body [18F]FDG hybrid imaging on the indications covered within this guideline was performed. All systematic reviews and meta-analyses published within the last 10 years until January 2023 were identified in PubMed/Medline or Cochrane. For each indication covered in this manuscript, diagnostic performance was provided based on meta-analyses or systematic reviews. If not available, results from prospective or retrospective studies were considered based on predefined selection criteria. RESULTS AND CONCLUSIONS: Hybrid [18F]FDG PET is extremely useful in the work-up and management of adults with infectious and inflammatory diseases, as supported by extensive and rapidly growing evidence-based literature and adoption in clinical guidelines. Practical recommendations are provided describing evidence-based indications as well as interpretation criteria and pitfalls. Monitoring treatment response is the most challenging but insufficiently studied potential application in infection and inflammation imaging.

Emerging multimodality imaging techniques for the pulmonary circulation

Pulmonary hypertension (PH) remains a challenging condition to diagnose, classify and treat. Current approaches to the assessment of PH include echocardiography, ventilation/perfusion scintigraphy, cross-sectional imaging using computed tomography and magnetic resonance imaging, and right heart catheterisation. However, these approaches only provide an indirect readout of the primary pathology of the disease: abnormal vascular remodelling in the pulmonary circulation. With the advent of newer imaging techniques, there is a shift toward increased utilisation of noninvasive high-resolution modalities that offer a more comprehensive cardiopulmonary assessment and improved visualisation of the different components of the pulmonary circulation. In this review, we explore advances in imaging of the pulmonary vasculature and their potential clinical translation. These include advances in diagnosis and assessing treatment response, as well as strategies that allow reduced radiation exposure and implementation of artificial intelligence technology. These emerging modalities hold the promise of developing a deeper understanding of pulmonary vascular disease and the impact of comorbidities. They also have the potential to improve patient outcomes by reducing time to diagnosis, refining classification, monitoring treatment response and improving our understanding of disease mechanisms.

Predictive biomarkers of response to tocilizumab in giant cell arteritis (GCA): correlations with imaging activity

In the recent EULAR recommendations, ultrasound examination is now recommended as a first-line imaging test in all patients with suspected giant cell arteritis (GCA) and the axillary arteries should be included in the standard exam. As an alternative to ultrasound evaluation, cranial and extracranial arteries can be examined using FDG-PET or MRI. The aim of our study was to observe in a retrospective case series whether there is a correlation between biomarkers and imaging activity in a population of patients followed in real life with GCA treated with prednisone (PDN) and tocilizumab (TCZ). We retrospectively enrolled 68 patients with newly diagnosed GCA between January 2020 and September 2021, followed in real life, who were examined at the Rheumatology Unit of the San Giovanni di Dio Hospital, Florence, Italy. Patients were evaluated at T0-T3-T6-T12-T18-T24 for the following blood tests: ESR, CRP, fibrinogen, platelet count, serum amyloid A (SAA), IL-6, and circulating calprotectin (MRP). Ultrasound examination of the temporal arteries and axillary arteries was assessed at T0 within 7 days of starting treatment with high-dose glucocorticoids and subsequently at T3-T6-T12-T18-T24. A scale from 0 to 3 with semi-quantitative tools (SUV max) was assessed at T0-T12-T24. The evaluation of the correlation coefficient between laboratory and imaging variables has shown that SAA and MRP have the most powerful correlation with the PET score (0.523 and 0.64), and MRP also has an excellent correlation coefficient with the Halo score (0.658). The evaluation of the ROC curves shows for a PET score 3 and SAA values higher than 26 mg/L, sensitivity of 81.5% and specificity of 84.1%, and for a PET score 3 and MRP values higher than 2.3 mcg/mL, sensitivity of 100% and specificity of 76.8%. In this study, we demonstrated that SAA and MRP can be useful as promising tools to detect GCA activity. The study demonstrates a good correlation between the two biomarkers and the imaging activity evaluated by the Halo and PET scores.

Visualization of cranial giant cell arteritis with [18F]FDG PET/CT: A case report

Giant cell arteritis is a form of large vessel vasculitis which can present with nonspecific symptoms, and if left untreated can cause significant morbidity and/or death. Early diagnosis and management are therefore paramount. The use of [18F]FDG PET/CT in the evaluation of giant cell arteritis has increased in recent years, with newer generation PET scanners capturing the historically elusive cranial vessel inflammation in active vasculitis. We present a case of giant cell arteritis which was suspected on conventional imaging modalities, and subsequently evaluated with [18F]FDG PET/CT which revealed marked vascular inflammation involving both cranial and other large vessels.

[News on the imaging of large vessel vasculitis]

Large vessel vasculitis, including giant cell arteritis (GCA) and Takayasu arteritis (TAK), are autoimmune diseases primarily affecting the aorta and its branches. GCA is the most common primary vasculitis. Inflammatory changes in the vessel walls can cause serious complications such as amaurosis, stroke, and aortic dissection and rupture. Imaging techniques have become an integral part for the diagnosis and monitoring of large vessel vasculitis, allowing for effective disease monitoring. GCA and TAK exhibit similar patterns of vascular distribution. However, the temporal arteries are never involved in TAK, and axillary arteritis occurs more frequently in GCA. In most centers, ultrasound of the temporal and axillary arteries has replaced temporal artery biopsy as the primary diagnostic tool for GCA. In addition to ultrasound, magnetic resonance imaging (MRI), computed tomography (CT), and [18F]-FDG (fluorodeoxyglucose) positron emission tomography-computed tomography (PET) are important, particularly for visualizing the aorta. Moreover, PET-CT is now also capable of assessing the temporal arteries, although it is not yet widely available. In polymyalgia rheumatica (PMR), ultrasound of the shoulder and hip regions is part of the ACR/EULAR classification criteria. MRI allows detailed visualization of additional inflammatory extraarticular manifestations, showing characteristic inflammatory lesions in entheses, tendons, and ligaments. [18F]-FDG-PET-CT also enables the visualization of musculoskeletal inflammation, especially in the shoulder and hip regions, as well as paravertebral areas. Ultrasound can detect subclinical GCA in up to 23% of patients with PMR, which should be treated like GCA. Technological innovations such as new radiotracers and improved MRI imaging could further enhance the diagnosis and monitoring of large vessel vasculitis and PMR, thus playing a crucial role in improving the prognosis through faster initiation of therapy.

Fibroblast activation protein inhibitor-positron emission tomography in aortitis: fibroblast pathology in active inflammation and remission

OBJECTIVES

Epigenetically modified fibroblasts contribute to chronicity in inflammatory diseases. Reasons for the relapsing character of large vessel vasculitis (LVV) remain obscure, including the role of fibroblasts, in part due to limited access to biopsies of involved tissue.68Ga FAPI-46 (FAPI)-PET/CT detects activated fibroblasts in vivo. In this exploratory pilot study, we tested the detection of fibroblast activation in vessel walls using FAPI-PET/CT in LVV with aortitis.

METHODS

Eight LVV patients with aortitis and eight age- and gender-matched controls were included. The distribution of FAPI uptake was evaluated in the aorta and large vessels. FAPI-uptake was compared with MRI inflammatory activity scores. Imaging results were compared with clinical parameters such as serum inflammatory markers, time of remission and medication.

RESULTS

Three aortitis patients were clinically active and five in remission. Irrespective of activity, FAPI uptake was significantly enhanced in aortitis compared with controls. Patients in remission had a mean duration of remission of 2.8 years (range 1-4 years), yet significant FAPI uptake in the vessel wall was found. In remitted aortitis, MRI inflammatory scores were close to be negative, while in 4/5 patients visually identifiable FAPI uptake was observed.

CONCLUSIONS

This pilot feasibility study shows significant tracer uptake in the aortic walls in LVV. FAPI positivity indicates ongoing fibroblast pathology in clinically remitted LVV.

Altered Plasma Levels and Tissue Expression of Fibroblast Activation Protein Alpha in Giant Cell Arteritis

OBJECTIVE

Giant cell arteritis (GCA) is characterized by granulomatous inflammation of the medium- and large-sized arteries accompanied by remodeling of the vessel wall. Fibroblast activation protein alpha (FAP) is a serine protease that promotes both inflammation and fibrosis. Here, we investigated the plasma levels and vascular expression of FAP in GCA.

METHODS

Plasma FAP levels were measured with enzyme-linked immunosorbent assay in treatment-naive patients with GCA (n = 60) and polymyalgia rheumatica (PMR) (n = 63) compared with age- and sex-matched healthy controls (HCs) (n = 42) and during follow-up, including treatment-free remission (TFR). Inflamed temporal artery biopsies (TABs) of patients with GCA (n = 9), noninflamed TABs (n = 14), and aorta samples from GCA-related (n = 9) and atherosclerosis-related aneurysm (n = 11) were stained for FAP using immunohistochemistry. Immunofluorescence staining was performed for fibroblasts (CD90), macrophages (CD68/CD206/folate receptor beta), vascular smooth muscle cells (desmin), myofibroblasts (α-smooth muscle actin), interleukin-6 (IL-6), and matrix metalloproteinase-9 (MMP-9).

RESULTS

Baseline plasma FAP levels were significantly lower in patients with GCA compared with patients with PMR and HCs and inversely correlated with systemic markers of inflammation and angiogenesis. FAP levels decreased even further at 3 months on remission in patients with GCA and gradually increased to the level of HCs in TFR. FAP expression was increased in inflamed TABs and aorta of patients with GCA compared with control tissues. FAP was abundantly expressed in fibroblasts and macrophages. Some of the FAP+ fibroblasts expressed IL-6 and MMP-9.

CONCLUSION

FAP expression in GCA is clearly modulated both in plasma and in vessels. FAP may be involved in the inflammatory and remodeling processes in GCA and have utility as a target for imaging and therapeutic intervention.

False-positive Findings of Large Vessel Vasculitis on FDG-PET in Patients Treated With Immune Checkpoint Inhibitors

Fluorine-18 fluorodeoxygluocose positron emission tomography (FDG-PET) is increasingly used in the evaluation of response to immune checkpoint inhibitor (ICI) therapy. Incidental findings of increased vessel wall uptake may prompt the concern for ICI-induced large vessel vasculitis (LVV). Precise radiographic and clinical evaluation is required to determine if this represents true vasculitis, as use of immune suppression and ICI discontinuation can have significant impacts on patient outcomes. We performed a retrospective case analysis of 4 consecutive patients referred to 2 rheumatology clinics treated with ICI with incidental findings of LVV on FDG-PET, reviewing their clinical course and radiographic findings. All 4 cases had FDG-PET scans for routine oncology indications and had no associated clinical features of LVV. One patient was treated with corticosteroids and no patients developed any clinical evidence of vasculitis during a mean follow-up period of 17 months (range: 7-33 mo). All FDG-PET images reporting LVV underwent a standardized analysis to identify any technical issues or concerns with interpretation. In review of imaging, 3 of the cases may have been due to delayed tracer to scan interval leading to misinterpretation of vascular uptake as suspected LVV. Recognition of technical pitfalls in FDG-PET interpretation is crucial to inform the need for immunosuppression and the safety of continued ICI therapy.

Advances in PET Imaging of Large Vessel Vasculitis: An Update and Future Trends

Systemic vasculitides are autoimmune diseases characterized by inflammation of blood vessels. They are categorized based on the size of the preferentially affected blood vessels: large-, medium-, and small-vessel vasculitides. The main forms of large-vessel vasculitis include giant cell arteritis (GCA) and Takayasu arteritis (TAK). Depending on the location of the affected vessels, various imaging modalities can be employed for diagnosis of large vessel vasculitis: ultrasonography (US), magnetic resonance angiography (MRA), computed tomography angiography (CTA), and [18F]-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (FDG-PET/CT). These imaging tools offer complementary information about vascular changes occurring in vasculitis. Recent advances in PET imaging in large vessel vasculitis include the introduction of digital long axial field-of-view PET/CT, dedicated acquisition, quantitative methodologies, and the availability of novel radiopharmaceuticals. This review aims to provide an update on the current status of PET imaging in large vessel vasculitis and to share the latest developments on imaging vasculitides.

FAPI-PET in Cardiovascular Disease

PET probes targeting fibroblasts are frequently used for varying applications in oncology. In recent years, the clinical spectrum has been expanded towards cardiovascular medicine, e.g., after myocardial infarction, in aortic stenosis or as a non-invasive read-out of atherosclerosis. We herein provide a brief overview of the current status of this PET radiotracer in the context of cardiovascular disease, including translational and clinical evidence. In addition, we will also briefly discuss future applications, e.g., the use of fibroblast-targeting PET to investigate bilateral organ function along the cardiorenal axis.

Imaging Response to Treatment in Rheumatology

This article highlights the crucial role of various imaging techniques in the diagnosis and monitoring of rheumatologic diseases. It provides an overview of the different modalities available for imaging rheumatic diseases, the disease processes they are able to demonstrate, and their utility in the monitoring response to therapy. It emphasizes the need for a multifaceted approach that combines radiography, ultrasound, MR imaging, and PET imaging to gain a comprehensive understanding of disease progression and treatment response. Standardized grading systems along with quantitative imaging techniques are playing an increasing role in monitoring disease activity and assessing response to therapy.

Role and potential of 18F-fluorodeoxyglucose-positron emission tomography-computed tomography in large-vessel vasculitis: a comprehensive review

Large-vessel vasculitis (LVV) is a group of diseases characterized by inflammation of the aorta and its main branches, which includes giant cell arteritis (GCA), polymyalgia rheumatica (PMR), and Takayasu's arteritis (TAK). These conditions pose significant diagnostic and management challenges due to their diverse clinical presentations and potential for serious complications. 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET-CT) has emerged as a valuable imaging modality for the diagnosis and monitoring of LVV, offering insights into disease activity, extent, and response to treatment. 18F-FDG-PET-CT plays a crucial role in the diagnosis and management of LVV by allowing to visualize vessel involvement, assess disease activity, and guide treatment decisions. Studies have demonstrated the utility of 18F-FDG-PET-CT in distinguishing between LVV subtypes, evaluating disease distribution, and detecting extracranial involvement in patients with cranial GCA or PMR phenotypes. Additionally, 18F-FDG-PET-CT has shown promising utility in predicting clinical outcomes and assessing treatment response, based on the correlation between reductions in FDG uptake and improved disease control. Future research should focus on further refining PET-CT techniques, exploring their utility in monitoring treatment response, and investigating novel imaging modalities such as PET-MRI for enhanced diagnostic accuracy in LVV. Overall, 18F-FDG-PET-CT represents a valuable tool in the multidisciplinary management of LVV, facilitating timely diagnosis and personalized treatment strategies to improve patient outcomes.

The utility of 18F-FDG-PET/CT in detecting extracranial large vessel vasculitis in rheumatic polymyalgia or giant cell arteritis. A systematic review and meta-analysis

OBJECTIVE

Systematic review of current evidence to analyze the prevalence of extracranial large vessel vasculitis (LVV) using 18F-FDG PET/CT in patients with polymyalgia rheumatica (PMR) or giant cell arteritis (GCA).

MATERIALS AND METHODS

PubMed and EMBASE were searched and the results were screened by two reviewers. Study quality was assessed using a modified version of the Newcastle-Ottawa scale. Heterogeneity between studies was assessed using the I2 statistic and the Q test. Further subgroup analyses were performed by disease type, study quality, and 18F-FDG PET/CT uptake criteria. Publication bias was assessed by funnel plot and Egger's test.

RESULTS

268 publications were identified, of which 17 met the selection criteria and were included in the meta-analysis. The overall pooled prevalence of extracranial LVV by 18F-FDG PET/CT was 54.5% [95% CI: 42.6%-66.1%]. In patients with GCA the prevalence was significantly higher than in patients with PMR (60.1% vs. 41.8%, P = 0.006). Likewise, studies with a lower risk of bias reported a higher prevalence of extracranial LVV (61.1% vs. 46.9%; P = 0.010). No publication bias was observed.

CONCLUSIONS

The 18F-FDG PET/CT test may be useful in the detection of extracranial LVV, both in patients with PMR or GCA. Such involvement is more frequent in patients with GCA, and may vary depending on the quality of the studies.

Prognostic value of 18 FDG-PET at diagnosis and follow-up in giant cell arteritis: An observational restrospective study

OBJECTIVES

To evaluate the ability of 18FDG PET/CT, at diagnosis of giant cell arteritis (GCA) and during follow-up, to predict occurrence of relapse in large-vessel GCA (LV-GCA).

METHODS

We conducted a retrospective study using the French Study Group for Large-Vessel Vasculitis (GEFA) network. Data from patients with LV-GCA diagnosed by PET/CT and who had PET/CT in the following year were collected. For each PET/CT, PET vascular activity score (PETVAS) and total vascular score (TVS) were assessed, and their ability to predict the occurrence of subsequent relapse was assessed.

RESULTS

A total of 65 LV-GCA patients were included, of whom 55 had undergone a follow-up PET/CT 3 to 12 months after the diagnosis of GCA. Patients for whom the second PET/CT (PET2) was performed during active GCA were excluded. PETVAS and TVS decreased between PET1 and PET2 in all patients (p < 0.001). There was no correlation between vascular activity scores in PET2 and time to prednisone taper. For relapse prediction, at PET1, the AUC of the TVS and PETVAS were respectively 51.9 and 41.9 at 6 months, 55.3 and 49.7 at 1 year, 55 and 55.7 at 2 years. For PET2, the AUC were respectively 46.1 and 46.7 at 6 months, 52.1 and 48.9 at 1 year, 58.4 and 52.3 at 2 years.

CONCLUSION

PET vascular activity scores at diagnosis and at follow-up PET/CT performed outside a period of GCA activity do not display high performance to predict the occurrence of subsequent relapse in LV-GCA patients.

The DANIsh VASculitis cohort study: protocol for a national multicenter prospective study including incident and prevalent patients with giant cell arteritis and polymyalgia rheumatica

The DANIsh VASculitis cohort study, DANIVAS, is an observational national multicenter study with the overall aim to prospectively collect protocolized clinical data and biobank material from patients with polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) diagnosed and/or followed at Danish rheumatology departments. A long-term key objective is to investigate whether the use of new clinically implemented diagnostic imaging modalities facilitates disease stratification in the GCA-PMR disease spectrum. In particular, we aim to evaluate treatment requirements in GCA patients with and without large-vessel involvement, treatment needs in PMR patients with and without subclinical giant cell arteritis, and the prognostic role of imaging with respect to aneurysm development. Hence, in GCA and PMR, imaging stratification is hypothesized to be able to guide management strategies. With an established infrastructure within rheumatology for clinical studies in Denmark, the infrastructure of the Danish Rheumatologic Biobank, and the possibility to cross-link data with valid nationwide registries, the DANIVAS project holds an exceptional possibility to collect comprehensive real-world data on diagnosis, disease severity, disease duration, treatment effect, complications, and adverse events. In this paper, we present the research protocol for the DANIVAS study. Clinical trial registration: https://clinicaltrials.gov/, identifier NCT05935709.

A systematic review for the evidence of recommendations and guidelines in hybrid nuclear cardiovascular imaging

OBJECTIVES

This study aimed to evaluate the level of evidence of expert recommendations and guidelines for clinical indications and procedurals in hybrid nuclear cardiovascular imaging.

METHODS

From inception to August 2023, a PubMed literature analysis of the latest version of guidelines for clinical hybrid cardiovascular imaging techniques including SPECT(/CT), PET(/CT), and PET(/MRI) was performed in two categories: (1) for clinical indications for all-in primary diagnosis; subgroup in prognosis and therapy evaluation; and for (2) imaging procedurals. We surveyed to what degree these followed a standard methodology to collect the data and provide levels of evidence, and for which topic systematic review evidence was executed.

RESULTS

A total of 76 guidelines, published between 2013 and 2023, were included. The evidence of guidelines was based on systematic reviews in 7.9% of cases, non-systematic reviews in 47.4% of cases, a mix of systematic and non-systematic reviews in 19.7%, and 25% of guidelines did not report any evidence. Search strategy was reported in 36.8% of cases. Strengths of recommendation were clearly reported in 25% of guidelines. The notion of external review was explicitly reported in 23.7% of cases. Finally, the support of a methodologist was reported in 11.8% of the included guidelines.

CONCLUSION

The use of evidence procedures for developing for evidence-based cardiovascular hybrid imaging recommendations and guidelines is currently suboptimal, highlighting the need for more standardized methodological procedures.

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.

The effect of prednisolone and a short-term prednisolone discontinuation for the diagnostic accuracy of FDG-PET/CT in polymyalgia rheumatica-a prospective study of 101 patients

PURPOSE

2-[18F]Fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has been suggested as an imaging modality to diagnose polymyalgia rheumatica (PMR). However, the applicability of FDG-PET/CT remains unclear, especially following glucocorticoid administration. This study aimed to investigate the diagnostic accuracy of FDG-PET/CT before and during prednisolone treatment, as well as following short-term prednisolone discontinuation.

METHODS

Treatment naïve suspected PMR patients were clinically diagnosed at baseline and subsequently had an FDG-PET/CT performed. Patients diagnosed with PMR were administered prednisolone following the first FDG-PET/CT and had a second FDG-PET/CT performed after 8 weeks of treatment. Subsequently, prednisolone was tapered with short-term discontinuation at week 9 followed by a third FDG-PET/CT at week 10. An FDG-PET/CT classification of PMR/non-PMR was applied, utilizing both the validated Leuven score and a dichotomous PMR score. The final diagnosis was based on clinical follow-up after 1 year.

RESULTS

A total of 68 and 27 patients received a final clinical diagnosis of PMR or non-PMR. A baseline FDG-PET/CT classified the patients as having PMR with a sensitivity/specificity of 86%/63% (Leuven score) and 82%/70% (dichotomous score). Comparing the subgroup of non-PMR with inflammatory diseases to the PMR group demonstrated a specificity of 39%/54% (Leuven/dichotomous score). After 8 weeks of prednisolone treatment, the sensitivity of FDG-PET/CT decreased to 36%/41% (Leuven/dichotomous score), while a short-term prednisolone discontinuation increased the sensitivity to 66%/60%.

CONCLUSION

FDG-PET/CT has limited diagnostic accuracy for differentiating PMR from other inflammatory diseases. If FDG-PET/CT is intended for diagnostic purposes, prednisolone should be discontinued to enhance diagnostic accuracy.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT04519580). Registered 17th of August 2020.

Recommendations of the French Society of Rheumatology for the management in current practice of patients with polymyalgia rheumatica

OBJECTIVE

To develop recommendations for the routine management of patients with polymyalgia rheumatica (PMR).

METHODS

Following standard procedures, a systematic review of the literature by five supervised junior rheumatologists, based on the questions selected by the steering committee (5 senior rheumatologists), was used as the basis for working meetings, followed by a one-day plenary meeting with the working group (15 members), leading to the development of the wording and determination of the strength of the recommendations and the level of agreement of the experts.

RESULTS

Five general principles and 19 recommendations were drawn up. Three recommendations relate to diagnosis and the use of imaging, and five to the assessment of the disease, its activity and comorbidities. Non-pharmacological therapies are the subject of one recommendation. Three recommendations concern initial treatment based on general corticosteroid therapy, five concern the reduction of corticosteroid therapy and follow-up, and two concern corticosteroid dependence and steroid-sparing treatments (anti-IL-6).

CONCLUSION

These recommendations take account of current data on PMR, with the aim of reducing exposure to corticosteroid therapy and its side effects in a fragile population. They are intended to be practical, to help practitioners in the day-to-day management of patients with PMR.

Severely increased albuminuria in patients with type 2 diabetes mellitus is associated with increased subclinical atherosclerosis in femoral arteries with Na [18F]F activity as a proxy - The DETERMINE study

BACKGROUND AND AIMS

Sodium [18F]fluoride (Na [18F]F) positron emission tomography imaging allows detailed visualization of early arterial micro-calcifications. This study aims to investigate atherosclerosis manifested by micro-calcification, macro-calcification, and aortic stiffness in patients with type 2 diabetes mellitus (T2DM) with and without albuminuria and severely decreased kidney function.

METHODS

A cohort was stratified in four groups (N = 10 per group), based on KDIGO categories (G1-5 A1-3). G1-2A1 non-diabetic controls (median [IQR] estimated glomerular filtration rate (eGFR) in mL/min/1.73 m2 91 [81-104]), G1-2A1 with T2DM (eGFR 87 [84-93], and albumin-creatinin-ratio (ACR) in mg/mmol 0.35 [0.25-0.75]), G1-2A3 with T2DM (eGFR 85 [60-103], and ACR 74 [62-122], and G4A3 with T2DM (eGFR 19 [13-27] and ACR 131 [59-304]).

RESULTS

Na [18F]F femoral artery grading score differed significantly in the groups with the highest Na [18F]F activity in A3 groups with T2DM (G1-2A3 with T2DM 228 [100-446] and G4A3 with T2DM 198 [113-578]) from the lowest groups of the G1-2A1 with T2DM (33 [0-93]) and in G1-2A1 non-diabetic controls (75 [0-200], p = 0.001). Aortic Na [18F]F activity and femoral artery computed tomography (CT)-assessed macro-calcification was increased in G4A3 with T2DM compared with G1-2A1 with T2DM (47.5 [33.8-73.8] vs. 17.5 [8.8-27.5] (p = 0.006) and 291 [170-511] vs. 12.2 [1.41-44.3] mg (p = 0.032), respectively). Carotid-femoral pulse wave velocity (PWV)-assessed aortic stiffness was significantly higher in both A3 groups with T2DM compared with G1-2A1 with T2DM (11.15 and 12.35 vs. 8.86 m/s, respectively (p = 0.009)).

CONCLUSIONS

This study indicates that the presence of severely increased albuminuria in patients with T2DM is cross-sectionally associated with subclinical arterial disease in terms of micro-calcification and aortic stiffness. Additional decrease in kidney function was associated with advanced macro-calcifications.

Molecular imaging of large vessel vasculitis

Large vessel vasculitis (LVV) affects mainly large arteries with giant cell arteritis (GCA) and Takayasu arteritis (TAK) being the two most frequent forms. Clinical symptoms can be non-specific, including headache, fatigue, weight loss, and change in vision. Untreated, LVV may also lead to serious complications such as blindness, aortic aneurysm and dissection. Therefore, rapid recognition of the disease leading to accurate diagnosis and appropriate treatment is essential. FDG-PET/CT imaging has emerged as a sensitive marker of active vascular inflammation and its use in the management of LVV is now integrated in guidelines. In this article, we will discuss the role of FDG-PET/CT for the diagnosis of LVV and monitoring of therapy, as well as review technical and interpretation parameters.

The usefulness of 18F-FDG-PET/CT in detecting musculoskeletal and vascular involvement in patients with polymyalgia rheumatica receiving glucocorticoids

OBJECTIVE

Fluorine-18-fluorodeoxyglucose (18F-FDG) PET/CT is a promising diagnostic tool for polymyalgia rheumatica (PMR) and large vessel vasculitis (LVV). PET/CT performance is recommended before the onset of steroid therapy because glucocorticoids (GC) may decrease the intensity of FDG uptake. However, this is not always possible in clinical practice. Our aim was to assess if PET/CT could be also useful to detect musculoskeletal and vascular involvement in patients receiving GC.

METHODS

Single-center study of patients with PMR diagnosis based on 2012 EULAR/ACR criteria who underwent a PET/CT scan due to LVV suspicion. We compared the musculoskeletal and vascular FDG uptake between two groups: (a) steroid-naïve and (b) steroid-resistant patients. A sub-analysis was conducted in patients who were receiving GC to discern if the cumulative prednisone dose influences the FDG uptake.

RESULTS

We evaluated 75 patients (27 men/ 48 women); mean age±SD: 68.2 ± 10.7 years. PET/CT was performed in 14 steroid-naïve and 61 steroid-resistant patients. Patients under GC had received a median cumulative prednisone dose of 1.8 [0.6-3.9] g. The pattern of musculoskeletal FDG uptake was similar in steroid-naïve and steroid-resistant patients. FDG uptake in the vessel wall was more frequently detected in steroid-naïve patients. However, PET/ CT was also useful to detect LVV in 62.3 % of the patients who were receiving GC. The percentage of patients who had positive PET/CT scans tended to decrease with higher cumulative prednisone doses.

CONCLUSION

Even though GC therapy may decrease the 18-FDG uptake, PET/CT continues to be a useful tool to detect musculoskeletal and LVV involvement in PMR.

Benefits and challenges of 18F-FDG PET/CT in patients with Takayasu arteritis

AIM

To evaluate the diagnostic performance of 2-[18F]-fluoro-2-deoxy-d-glucose (18F-FDG) positron-emission tomography (PET)/computed tomography (CT) in TA diagnosis and Takayasu arteritis (TA) activity assessment.

MATERIALS AND METHODS

This retrospective study included patients with TA diagnosed according to the American College of Rheumatology (ACR) criteria and undergoing 18F-FDG PET/CT imaging from October 2010 to July 2022. TA activity was assessed through 18F-FDG PET/CT (maximum standard uptake value [SUVmax], vascular SUVmax/mean standard uptake value [SUVmean] of liver (SUV ratio), and PET vascular activity score [PETVAS]) using physician global assessment (PGA) as the reference standard, and the results of these assessments were compared against the clinical activity scores (National Institutes of Health [NIH] and Indian Aortitis Disease Activity [ITAS-A] scores), acute-phase reactants (APR), and white blood cell and platelet counts.

RESULTS

Twenty 18F-FDG PET/CT examinations from 19 patients were included in the study, nine were performed in the active phase and 11 in the inactive phase. The involved vessels showed segmental and tubular FDG uptake in the active group. The average SUVmax, SUV ratio, and PETVAS was 6.3 ± 2.7 (range 3.4-12), 4.2 ± 1.7 (range 2.1-7.5), and 22.7 ± 11.2 (range 6-39), respectively, in the active group and 1.7 ± 0.9 (0.9-3.1), 1.1 ± 0.6 (range 0.6-2.4), and 3.5 ± 5.5 (range 0-18), respectively, in the inactive group. The sensitivity, specificity of SUVmax, SUV ratio, and PETVAS for TA activity assessment were 100%, 100%; 100%, 90.9%; and 88.9, 90.9%, respectively. After ROC curve analysis, a new SUVmax cut-off was obtained. Based on the new cut-off value, SUVmax 3.3 and SUV ratio 1.9 had a more perfect assessment performance.

CONCLUSION

18F-FDG PET/CT is an alternative imaging technique for TA.

[18F]FDG-PET/CT in Polymyalgia Rheumatica: An Update and Future Aspects

Polymyalgia rheumatica (PMR) is an inflammatory disorder usually diagnosed in patients older than 50 years of age. It is characterized by sudden onset pain and prolonged morning stiffness in the scapular and/or pelvic girdle, sometimes debilitating and accompanied by constitutional symptoms such as weight loss. In approximately 20% of the cases, it is linked to giant cell arteritis (GCAV) representing a disease continuum. The diagnosis is mainly clinical and noninvasive imaging such as ultrasound of joints may be helpful. In atypical PMR cases, whole body imaging using [18F]FDG-PET/CT may be useful. First, to confirm or rule out the diagnosis of PMR, secondly, to assess the coexistence of a GCA, and thirdly to establish the differential diagnosis with other types of arthritides encountered in this age group, such as elderly-onset rheumatoid arthritis, spondyloarthropathies, crystal-induced arthropathies or the rare remittent seronegative symmetrical synovitis with pitting edema. Relatively typical patterns of [18F]FDG-PET/CT are well known, based on the clinical distribution of the disease (eg, scapular and pelvic girdle, interspinous bursae, sterno-costoclavicular joints, entheses), especially the hypermetabolism at the interspinous lumbar bursae that has shown the best post-test likelihood ratio in a meta-analysis. This article focuses on the differential diagnosis and on the visual and semi-quantitative tools that can be used to guide to the correct diagnosis of PMR as an add-on to the clinical picture. Further, we briefly discuss the options that can improve molecular imaging in the future for inflammatory rheumatisms in elderly.

Multi-Modality Imaging in Vasculitis

Systemic vasculitides are a rare and complex group of diseases that can affect multiple organ systems. Clinically, presentation may be vague and non-specific and as such, diagnosis and subsequent management are challenging. These entities are typically classified by the size of vessel involved, including large-vessel vasculitis (giant cell arteritis, Takayasu's arteritis, and clinically isolated aortitis), medium-vessel vasculitis (including polyarteritis nodosa and Kawasaki disease), and small-vessel vasculitis (granulomatosis with polyangiitis and eosinophilic granulomatosis with polyangiitis). There are also other systemic vasculitides that do not fit in to these categories, such as Behcet's disease, Cogan syndrome, and IgG4-related disease. Advances in medical imaging modalities have revolutionized the approach to diagnosis of these diseases. Specifically, color Doppler ultrasound, computed tomography and angiography, magnetic resonance imaging, positron emission tomography, or invasive catheterization as indicated have become fundamental in the work up of any patient with suspected systemic or localized vasculitis. This review presents the key diagnostic imaging modalities and their clinical utility in the evaluation of systemic vasculitis.

Relevance of blood tumor markers in inpatients with significant involuntary weight loss and elevated levels of inflammation biomarkers

PURPOSE

To assess the diagnostic performance of a panel of standard tumor markers (TMs) in patients hospitalized with significant involuntary weight loss (IWL) and elevated levels of inflammation biomarkers, and a combination of the TM panel and the finding of the computed tomography (CT) scan.

METHODS

We conducted a retrospective study in the internal medicine department at Amiens-Picardie University Medical Center (Amiens, France) between January 1st, 2015, and November 1st, 2021. The inclusion criteria were age 18 or over, significant IWL (≥ 5 kg over 6 months), elevated inflammation biomarkers (e.g. C-reactive protein), and assay data on two or more standard TMs (carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 19 - 9, CA 15 - 3, CA 125, neuron-specific enolase (NSE), alpha-fetoprotein (AFP), calcitonin, and prostate-specific antigen (PSA)). The result of each TM assay was interpreted qualitatively (as positive or negative), according to our central laboratory's usual thresholds.

RESULTS

Cancer was diagnosed in 50 (37.0%) of the 135 patients included. Positivity for one or more TMs had a positive predictive value (PPV) of 0.55 [0.43-0.66], and a negative predictive value (NPV) of 0.84 [0.75-0.93] for cancer diagnosis. When combined with the presence of suspicious CT findings (e.g. a mass, enlarged lymph nodes and/or effusion), positivity for one or more TMs had a PPV of 0.92 [0.08-0.30]. In the absence of suspicious CT findings, a fully negative TM panel had an NPV of 0.96 [0.89-1.00].

CONCLUSION

A negative TM panel argues against the presence of a cancer, especially in the absence of suspicious CT findings.

[18F]FDG PET/CT for therapeutic assessment of Abatacept in early-onset polymyalgia rheumatica

PURPOSE

Evaluate the benefit of 2-deoxy-2-[18F]-fluoro-D-glucose ([18F] FDG) positron emission tomography/computed tomography (PET/CT) for the therapeutic assessment of Abatacept (ABA) as first-line therapy in early-onset polymyalgia rheumatica (PMR) patients.

METHODS

This was an ancillary study of ALORS trial (Abatacept in earLy Onset polymyalgia Rheumatica Study) assessing the ability of ABA versus placebo to achieve low disease activity (C-Reactive Protein PMR activity score (CRP PMR-AS) ≤ to 10) without glucocorticoid (GC) at week 12 in patients with early-onset PMR. The patients underwent [18F] FDG PET/CT at baseline and after 12 weeks of treatment. Responses to treatments were evaluated according to CRP PMR-AS, Erythrocyte Sedimentation Rate (ESR) PMR-AS, Clin PMR-AS, and CRP-Imputed (Imput-CRP) PMR-AS. Quantitative score by maximal standardized uptake value (SUVmax) and combined qualitative scores according to liver uptake (Leuven, Leuven/Groningen, and Besançon Scores) were used for assessment of [18F] FDG uptake in regions of interest (ROI) usually affected in PMR. Student's t-test was applied to evaluate the clinical, biological, and [18F] FDG uptake variation difference in ABA and placebo groups between W0 and W12. Subgroup analysis by GC rescue was performed.

RESULTS

At W12, there was no significant difference according to SUVmax between the ABA and the placebo groups in all ROI. Subgroup analysis according to GC administration demonstrated a significant (p 0.047) decrease in SUVmax within the left sternoclavicular joint ROI in the ABA group (- 0.8) compared to the placebo group (+ 0.6) without GC rescue. Other results did not reveal any significant difference between the ABA and placebo groups. According to combined qualitative scores, there was no significant difference between ABA and placebo groups for the direct comparison analysis and subgroup analysis according to GC rescue.

CONCLUSION

[18F] FDG PET/CT uptake did not decrease significantly after ABA compared to placebo in anatomical areas usually affected in PMR patients. These results are correlated with the clinical-biological therapeutic assessment.

CLINICAL TRIAL REGISTRATION

The study was approved by the appropriate ethics committee (CPP Sud-Est II Ref CPP: 2018-33), and all patients gave their written informed consent before study enrollment. The protocol was registered on Clinicaltrials.gov (NCT03632187).

Comprehensive literature review of oral and intravenous contrast-enhanced PET/CT: a step forward?

The integration of diagnostic CT scans into PET/CT facilitates a comprehensive single examination, presenting potential advantages for patients seeking a thorough one-shot check-up. The introduction of iodinated contrast media during PET scanning raises theoretical concerns about potential interference with uptake quantification, due to the modification of tissue density on CT. Nevertheless, this impact appears generally insignificant for clinical use, compared to the intrinsic variability of standardized uptake values. On the other hand, with the growing indications of PET, especially 18F-FDG PET, contrast enhancement increases the diagnostic performances of the exam, and provides additional information. This improvement in performance achieved through contrast-enhanced PET/CT must be carefully evaluated considering the associated risks and side-effects stemming from the administration of iodinated contrast media. Within this article, we present a comprehensive literature review of contrast enhanced PET/CT, examining the potential impact of iodinated contrast media on quantification, additional side-effects and the pivotal clinically demonstrated benefits of an all-encompassing examination for patients. In conclusion, the clinical benefits of iodinated contrast media are mainly validated by the large diffusion in PET protocols. Contrary to positive oral contrast, which does not appear to offer any major advantage in patient management, intravenous iodine contrast media provides clinical benefits without significant artifact on images or quantification. However, studies on the benefit-risk balance for patients are still lacking.

Advancements in non-invasive imaging of atherosclerosis: Future perspectives

Atherosclerosis is a chronic inflammatory disease characterized by the buildup of plaques in arterial walls, leading to cardiovascular diseases and high morbidity and mortality rates worldwide. Non-invasive imaging techniques play a crucial role in evaluating patients with suspected or established atherosclerosis. However, there is a growing body of evidence suggesting the need to visualize the underlying processes of plaque progression and rupture to enhance risk stratification. This review explores recent advancements in non-invasive assessment of atherosclerosis, focusing on computed tomography, magnetic resonance imaging, and nuclear imaging. These advancements provide valuable insights into the assessment and management of atherosclerosis, potentially leading to better risk stratification and improved patient outcomes.

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.

Total-Body PET/CT Applications in Cardiovascular Diseases: A Perspective Document of the SNMMI Cardiovascular Council

Digital PET/CT systems with a long axial field of view have become available and are emerging as the current state of the art. These new camera systems provide wider anatomic coverage, leading to major increases in system sensitivity. Preliminary results have demonstrated improvements in image quality and quantification, as well as substantial advantages in tracer kinetic modeling from dynamic imaging. These systems also potentially allow for low-dose examinations and major reductions in acquisition time. Thereby, they hold great promise to improve PET-based interrogation of cardiac physiology and biology. Additionally, the whole-body coverage enables simultaneous assessment of multiple organs and the large vascular structures of the body, opening new opportunities for imaging systemic mechanisms, disorders, or treatments and their interactions with the cardiovascular system as a whole. The aim of this perspective document is to debate the potential applications, challenges, opportunities, and remaining challenges of applying PET/CT with a long axial field of view to the field of cardiovascular disease.

Characterising polymyalgia rheumatica on whole-body 18F-FDG PET/CT: an atlas

The impact of modern imaging in uncovering the underlying pathology of PMR cannot be understated. Long dismissed as an inflammatory syndrome with links to the large vessel vasculitis giant cell arteritis (GCA), a pathognomonic pattern of musculotendinous inflammation is now attributed to PMR and may be used to confirm its diagnosis. Among the available modalities, 18F-fluorodeoxyglucose (18F-FDG) PET/CT is increasingly recognized for its high sensitivity and specificity, as well as added ability to detect concomitant large vessel GCA and exclude other relevant differentials like infection and malignancy. This atlas provides a contemporary depiction of PMR's pathology and outlines how this knowledge translates into a pattern of findings on whole body 18F-FDG PET/CT that can reliably confirm its diagnosis.

Metabolic and molecular imaging in inflammatory arthritis

It is known that metabolic shifts and tissue remodelling precede the development of visible inflammation and structural organ damage in inflammatory rheumatic diseases such as the inflammatory arthritides. As such, visualising and measuring metabolic tissue activity could be useful to identify biomarkers of disease activity already in a very early phase. Recent advances in imaging have led to the development of so-called 'metabolic imaging' tools that can detect these changes in metabolism in an increasingly accurate manner and non-invasively.Nuclear imaging techniques such as 18F-D-glucose and fibroblast activation protein inhibitor-labelled positron emission tomography are increasingly used and have yielded impressing results in the visualisation (including whole-body staging) of inflammatory changes in both early and established arthritis. Furthermore, optical imaging-based bedside techniques such as multispectral optoacoustic tomography and fluorescence optical imaging are advancing our understanding of arthritis by identifying intra-articular metabolic changes that correlate with the onset of inflammation with high precision and without the need of ionising radiation.Metabolic imaging holds great potential for improving the management of patients with inflammatory arthritis by contributing to early disease interception and improving diagnostic accuracy, thereby paving the way for a more personalised approach to therapy strategies including preventive strategies. In this narrative review, we discuss state-of-the-art metabolic imaging methods used in the assessment of arthritis and inflammation, and we advocate for more extensive research endeavours to elucidate their full field of application in rheumatology.

Difference in arterial FDG accumulation in healthy study participants between digital PET/CT and standard PET/CT

OBJECTIVE

To evaluate the differences in FDG accumulation in arteries throughout the body between digital and standard PET/CT.

METHODS

Forty-six people who had FDG-PET examinations with a digital PET/CT scanner for health screening between April 2020 and March 2021 and had previous examinations with a standard PET/CT scanner were the study participants. FDG accumulation in arteries throughout the body was visually assessed in each segment. Scan was considered positive when arterial FDG accumulation was equal to or greater than that of the liver. The positivity rates for general arteries and each arterial segment were compared between the two kinds of scanners. If any one of the arterial segments was considered positive, the general arteries were classified as positive. Moreover, the rate of change in results from the standard PET/CT to the digital scanner in the same individual (negative to positive, positive to negative) was examined.

RESULTS

In the evaluation of general arteries, the positivity rates were 21.7% (10 cases) for the standard PET/CT, whereas positive rates were 97.8% (45 cases) for the digital PET/CT (p < 0.001). In all arterial segments, the positivity rate was significantly higher with the digital PET/CT compared to the standard PET/CT; those with the digital PET/CT were, respectively, 95.7%, 87.0%, 73.9%, 37.0%, 34.8%, and 21.7% in the femoral, brachial, aortic, subclavian, iliac, and carotid arteries. On the other hand, those with the standard PET/CT were 13.0%, 13.0%, 19.6%, 2.2%, 0%, and 4.4% in segments in the above order. Changes from negative to positive were shown in many cases; 35 cases (76.0%) of general arteries, 38 cases (82.6%) for the femoral artery, and 34 cases (73.9%) for the brachial artery. The exception was one case in which a change from positive to negative was confirmed in the carotid artery. In all arteries considered to be positive, FDG accumulation was not greater than but was equal to that in the liver with both scanners.

CONCLUSIONS

Arterial FDG accumulation was significantly higher with digital PET/CT compared to conventional PET/CT. With digital PET/CT, an arterial FDG accumulation equal to the liver may not to be considered as abnormal accumulation.

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.

Usefulness of 18F-FDG PET-CT for assessing large-vessel involvement in patients with suspected giant cell arteritis and negative temporal artery biopsy

OBJECTIVE

To investigate the usefulness of 18F-FDG PET-CT for assessing large-vessel (LV) involvement in patients with suspected giant cell arteritis (GCA) and a negative temporal artery biopsy (TAB).

METHODS

A retrospective review of our hospital databases was conducted to identify patients with suspected GCA and negative TAB who underwent an 18F-FDG PET-CT in an attempt to confirm the diagnosis. The gold standard for GCA diagnosis was clinical confirmation after a follow-up period of at least 12 months.

RESULTS

Out of the 127 patients included in the study, 73 were diagnosed with GCA after a detailed review of their medical records. Of the 73 patients finally diagnosed with GCA, 18F-FDG PET-CT was considered positive in 61 cases (83.5%). Among the 54 patients without GCA, 18F-FDG PET-CT was considered positive in only eight cases (14.8%), which included 1 case of Erdheim-Chester disease, 3 cases of IgG4-related disease, 1 case of sarcoidosis, and 3 cases of isolated aortitis. Overall, the diagnostic performance of 18F-FDG PET-CT for assessing LV involvement in patients finally diagnosed with GCA and negative TAB yielded a sensitivity of 83.5%, specificity of 85.1%, and a diagnostic accuracy of 84% with an area under the ROC curve of 0.844 (95% CI: 0.752 to 0.936). The sensitivity was 89% in occult systemic GCA and 100% in extracranial LV-GCA.

CONCLUSION

Our study confirms the utility of 18F-FDG PET-CT in patients presenting with suspected GCA and a negative TAB by demonstrating the presence of LV involvement across different subsets of the disease.

Decoding polymyalgia rheumatica, the role of Nuclear Medicine Imaging

Polymyalgia rheumatica (PMR) is an inflammatory joint disease that presents in patients older than 50 years with prolonged morning pain and stiffness in the shoulder and hip joints and neck. The lack of specific clinical findings, laboratory signs, biomarkers and established imaging methods makes it difficult to diagnose patients with this disease. 18F-FDG PET/CT is a functional imaging technique that is an established tool in oncology and has also proven useful in the field of inflammatory diseases. The aim of this paper is to present literature evidence on the use of molecular imaging methods such as PET/CT for early diagnosis, assessment of disease activity and therapeutic response in PMR. At the same time, the advantages, disadvantages and contraindications of other methods are considered.

Phlebitis in Takayasu arteritis: A case-based literature review

Takayasu arteritis (TAK) is the main type of large vessel arteritis in young adults, which mainly affects the aorta and its main branches, leading to clinical manifestations such as syncope, intermittent limb claudication, hypertension, and abdominal pain. Among them, venous involvement is rarely reported. Here we show a case of TAK presenting as phlebitis. This was a 27-year-old woman, who initially admitted to our hospital with myalgia of the upper and lower extremities and night sweats. She was diagnosed as TAK according to the 1990 American College of Rheumatology TAK criteria. Surprisingly, vascular ultrasonography revealed wall thickening as indicated by macaroni sign of the multiple veins. TAK phlebitis appeared at the active phase, while disappearing rapidly at remission. Phlebitis might have a close relationship with disease activity. By retrospective study in our department, the estimated incidence rate of phlebitis might be 9.1% in TAK. With the literature review, it revealed that phlebitis might be an ignored manifestation in active TAK. However, due to the smaller sample size, it should be noted that a direct cause-effect relationship cannot be established.

Comparing Diagnostic Performance of Short and Long [18F]FDG-PET Acquisition Times in Giant Cell Arteritis

(1) Background: In giant cell arteritis (GCA), the assessment of cranial arteries using [18F]fluorodeoxyglucose ([18F]FDG) positron emission tomography (PET) combined with low-dose computed tomography (CT) may be challenging due to low image quality. This study aimed to investigate the effect of prolonged acquisition time on the diagnostic performance of [18F]FDG PET/CT in GCA. (2) Methods: Patients with suspected GCA underwent [18F]FDG-PET imaging with a short acquisition time (SAT) and long acquisition time (LAT). Two nuclear medicine physicians (NMPs) reported the presence or absence of GCA according to the overall image impression (gestalt) and total vascular score (TVS) of the cranial arteries. Inter-observer agreement and intra-observer agreement were assessed. (3) Results: In total, 38 patients were included, of whom 20 were diagnosed with GCA and 18 were without it. Sensitivity and specificity for GCA on SAT scans were 80% and 72%, respectively, for the first NMP, and 55% and 89% for the second NMP. On the LAT scans, these values were 65% and 83%, and 75% and 83%, respectively. When using the TVS, LAT scans showed especially increased specificity (94% for both NMPs). Observer agreement was higher on the LAT scans compared with that on the SAT scan. (4) Conclusions: LAT combined with the use of the TVS may decrease the number of false-positive assessments of [18F]FDG PET/CT. Additionally, LAT and TVS may increase both inter and intra-observer agreement.

What Role Does PET/MRI Play in Musculoskeletal Disorders?

Musculoskeletal disorders of nononcological origin are one of the most frequent reasons for consultation. Patients suffering from musculoskeletal disorders also consult more than once for the same reason. This results in multiple clinical follow-ups after several radiological and serum examinations, the main ones including X-rays targeting the painful anatomical region and inflammatory serum parameters. As part of their work up, patients suffering from musculoskeletal disorders often require multisequence, multi-parameter MRI. PET/MRI is a promising imaging modality for their diagnosis, with the added advantage of being able to be performed in a single visit. PET/MRI is particularly useful for diagnosing osteomyelitis, spondylodiscitis, arthritis, many pediatric pathologies, and a wide range of other musculoskeletal pathologies. PET/MRI is already used to diagnose malignant bone tumors such as osteosarcoma. However, current knowledge of the indications for PET/MRI in nononcological musculoskeletal disorders is based on studies involving only a few patients. This review focuses on the usefulness of PET/MRI for diagnosing nononcological musculoskeletal disorders.

The clinical value of quantitative cardiovascular molecular imaging: a step towards precision medicine

Cardiovascular diseases (CVD) are the leading cause of death worldwide and have an increasing impact on society. Precision medicine, in which optimal care is identified for an individual or a group of individuals rather than for the average population, might provide significant health benefits for this patient group and decrease CVD morbidity and mortality. Molecular imaging provides the opportunity to assess biological processes in individuals in addition to anatomical context provided by other imaging modalities and could prove to be essential in the implementation of precision medicine in CVD. New developments in single-photon emission computed tomography (SPECT) and positron emission tomography (PET) systems, combined with rapid innovations in promising and specific radiopharmaceuticals, provide an impressive improvement of diagnostic accuracy and therapy evaluation. This may result in improved health outcomes in CVD patients, thereby reducing societal impact. Furthermore, recent technical advances have led to new possibilities for accurate image quantification, dynamic imaging, and quantification of radiotracer kinetics. This potentially allows for better evaluation of disease activity over time and treatment response monitoring. However, the clinical implementation of these new methods has been slow. This review describes the recent advances in molecular imaging and the clinical value of quantitative PET and SPECT in various fields in cardiovascular molecular imaging, such as atherosclerosis, myocardial perfusion and ischemia, infiltrative cardiomyopathies, systemic vascular diseases, and infectious cardiovascular diseases. Moreover, the challenges that need to be overcome to achieve clinical translation are addressed, and future directions are provided.