The Utility of 18F-FDG PET/CT in Patients With Clinical Suspicion of Polymyalgia Rheumatica and Giant Cell Arteritis: A Prospective, Observational, and Cross-sectional Study

Presence of subclinical giant cell arteritis in patients with morning stiffness of duration less than 45 minutes at the time of diagnosis of polymyalgia rheumatica

Introduction

In some patients with polymyalgia rheumatica (PMR), giant cell arteritis (GCA) is subclinical as underlying inflammation of large vessels (LV) is present without evidence of related clinical manifestations. Different factors have been proposed as predictive of subclinical GCA in PMR patients. To date, the literature reports scant data about the association between subclinical GCA and long-lasting morning stiffness (MS) in patients at the time of diagnosis of PMR. Given this background, the aim of this study was to assess the association between subclinical GCA and MS < 45 min in patients with newly diagnosed PMR.

Material and methods

We performed an observational, retrospective, single-centre cohort study of patients consecutively referred to our public out-of-hospital rheumatologic clinic between January 2015 and December 2020, who could be classified as having PMR according to the 2012 EULAR/ACR criteria. Subclinical GCA was investigated through ultrasound examination of a core set of arteries (temporal, axillary, common carotid, and subclavian arteries), in accordance with the EULAR recommendations for the use of imaging in LV vasculitis. Patients who did not have GCA symptoms but showed halo sign in at least one of these arteries were described as having subclinical GCA.

Results

We included a total of 143 patients (35 men and 108 women). Their median age was of 71.5 years. Thirty-five had MS duration < 45 min at the time of PMR diagnosis. Subclinical GCA was found in 23 PMR patients (16.1%); 18 had a cranial and 5 an extracranial GCA. A univariate analysis highlighted that MS < 45 min was associated with a lower prevalence of GCA (OR = 0.11, 95% CI: 0.04-0.29; p < 0.0001). This association was retained in a multivariable analysis that accounted for 6 different potential covariates (OR = 0.06, 95% CI: 0.01-0.26; p < 0.0001.

Conclusions

In our study MS < 45 min at the time of PMR diagnosis was associated with a significantly lower risk of subclinical GCA, when patients were screened by ultrasound, of approximately 90%. Identification of a more accurate MS cut-off value could improve the accuracy for subclinical GCA in patients with newly diagnosed PMR.

Early referral of patients with suspected polymyalgia rheumatica - A systematic review

INTRODUCTION

Prompt diagnosis and treatment of polymyalgia rheumatica (PMR) is crucial to prevent long-term complications and improve patient outcomes. However, there is currently no standardized approach to referral of suspected PMR patients to rheumatologists, leading to inconsistent management practices. The objective of this systematic review was to clarify the existing evidence regarding the following aspects of early management strategies in patients with suspected PMR: diagnostic strategies, GCA screening, glucocorticoid initiation prior to referral, value of shared care and value of fast track clinic.

METHODS

Two authors performed a systematic literature search, data extraction and risk of bias assessment independently. The literature search was conducted in Embase, MEDLINE (PubMed) and Cochrane. Studies were included if they contained cohorts of suspected PMR patients and evaluated the efficacy of different diagnostic strategies for PMR, screening for giant cell arteritis (GCA), starting glucocorticoids before referral to secondary care, shared care, or fast-track clinics.

RESULTS

From 2,437 records excluding duplicates, 14 studies met the inclusion criteria. Among these, 10 studies investigated the diagnostic accuracy of various diagnostic strategies with the majority evaluating different clinical approaches, but none of them showed consistently high performance. However, 4 studies on shared care and fast-track clinics showed promising results, including reduced hospitalization rates, lower starting doses of glucocorticoids, and faster PMR diagnosis.

CONCLUSION

This review emphasizes the sparse evidence of early management and referral strategies for patients with suspected PMR. Additionally, screening and diagnostic strategies for differentiating PMR from other diseases, including concurrent GCA, require clarification. Fast-track clinics may have potential to aid patients with PMR in the future, but studies will be needed to determine the appropriate pre-referral work-up.

Temporal artery biopsy for suspected giant cell arteritis: A mini review

Giant cell arteritis (GCA) is a granulomatous inflammation involving medium and large vessels that can lead to serious clinical manifestations associated with tissue ischemia. Temporal artery biopsy (TAB) is currently the gold standard method for the diagnosis of GCA, with a specificity of 100% and a sensitivity of 77%. However, the false-negative rate for TAB ranges from 9% to 61%. False negatives may be related to the timing of biopsy, the length of specimen, and the existence of "skip lesions." We reviewed the relevant evidence for methods to improve the sensitivity and reduce the false-negative rate for TAB. To reduce the false-negative rate for TAB, it is recommended to perform TAB within 1 week of starting corticosteroid therapy. Although there is currently no consensus, we suggest that the temporal artery is cut to a length of 20‒30 mm and to prepare serial pathological sections. It is necessary to attach great importance to patients suspected of having GCA, and complete TAB should be performed as soon as possible while starting corticosteroid therapy promptly. We also discuss the clinical value of non-invasive vascular imaging technologies, such as DUS, CTA, MRA, and 18F-FDG-PET/CT, as auxiliary methods for GCA diagnosis that could partially replace TAB.

The role of 18F-fluorodeoxyglucose PET/computed tomography in the diagnosis and monitoring of large vessel vasculitides - a review article

In the last two decades, advancements in positron emission tomography (PET) technology have increased the diagnostic accuracy of patients with large-vessel vasculitis (LVV). Numerous systematic reviews and meta-analyses have been conducted, and patients suspected of having LVV can be diagnosed earlier with 18F-FDG PET. Two subtypes, giant cell arteritis (GCA) and Takayasu arteritis (TA), will progress when their response to corticosteroids and enhanced immunosuppression is inadequate. In the majority of patients, disease activity cannot be monitored solely through laboratory procedures; consequently, glucose metabolism may be a source of potential biomarkers. In this article, we discuss the current state of 18F-FDG PET/CT imaging standards.

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.

[Polymyalgia rheumatica in 18-fluorodeoxyglucose-positron-emission-tomography/computed tomography : Improvement in diagnostic accuracy and differentiation from rheumatoid arthritis]

BACKGROUND

The diagnosis of patients with polymyalgia rheumatica (PMR) has relied upon the clinical examination of symptoms and laboratory parameters of inflammation until now. Currently, the use of different imaging modalities is being explored, including ultrasound, MRI and PET.

OBJECTIVES

The aim was to evaluate the diagnostic value of 18-fluorodeoxyglucose-positron-emission-tomography/computed tomography (18F-FDG-PET/CT) for PMR, in order to improve the sensitivity and specificity of diagnosing PMR and to improve the differential diagnosis of rheumatoid arthritis (RA).

MATERIALS AND METHODS

Examinations using 18F-FDG-PET/CT of 284 rheumatological patients, including 97 patients with PMR, were retrospectively evaluated over a 44-month period. Furthermore, 13 regions changed by inflammation were analysed via a three-dimensional region of interest (ROI) measurement with determination of maximum standardized uptake values (SUVmax), followed by statistical analyses.

RESULTS AND DISCUSSION

Patients with PMR presented significantly elevated uptake in all regions examined (p < 0.001), compared with a control group treated for rheumatological diseases. The method with the highest diagnostic relevance was represented by the combination of four SUVmax values of both anterolateral hip capsules and both ischial tuberosities, reaching a sensitivity of 91.3% and a specificity of 97.6% with a cut-off of 11.0 SUV at the initial diagnosis of PMR patients who had not yet received any immunosuppressive therapy. Patients with RA could be significantly distinguished from those with PMR at initial diagnosis in the same anatomical regions (p < 0.001).

Diagnostic accuracy and validation of 18F-fluorodeoxyglucose positron emission tomography scores in a large cohort of patients with polymyalgia rheumatica

Background

Several studies have shown that ¹⁸F-FDG PET may contribute to the diagnosis of polymyalgia rheumatica (PMR). Previously, we developed a composite PET score called the Leuven score, which was recently adapted to the more concise Leuven/Groningen score by van der Geest et al. The aim of this study is to validate and compare the diagnostic accuracy and cut-off points of both scores in a large cohort of PMR patients.

Methods

Patients with a possible clinical diagnosis of PMR and a PET scan prior to the initiation of glucocorticoids between 2003 and 2020 were included retrospectively. The gold standard for the diagnosis of PMR was the judgment of two experienced clinicians after a follow-up of at least 6 months. FDG uptake was scored visually in 12 articular regions (scores 0–2) and a total skeletal score was calculated by summing the individual scores (maximum of 24 for the Leuven score and 14 for the Leuven/Groningen score). Receiver operating characteristic (ROC) analysis and the Youden index were used to determine the diagnostic accuracy and optimal cut-off points.

Results

A total of 162 patients with PMR and 83 control patients were included. Both PET scores showed high diagnostic accuracy in the ROC analysis (area under the curve 0.986 and 0.980, respectively). The Leuven Score provided a sensitivity of 91.4%, specificity of 97.6% and accuracy of 93.5% at its predefined cut-off point of 16. With the newly determined cut-off point of 12 the sensitivity was 98.8%, the specificity 95.2% and the accuracy 97.6%. The Leuven/Groningen score had a sensitivity, specificity and accuracy of 93.2%, 95.2%, and 93.9%, respectively, with the pre-specified cut-off point of 8, and 96.9%, 92.8%, and 95.5% with the optimal cut-off point of 7.

Conclusion

The original Leuven score and the simplified Leuven/Groningen score both had excellent diagnostic accuracy. The latter may be easier to apply in clinical practice.

Diagnostic performance of 18 F-FDG-PET/CT in inflammation of unknown origin: A clinical series of 317 patients

BACKGROUND

Inflammation of unknown origin (IUO) is a challenging situation in internal medicine.

OBJECTIVES

To describe the final diagnoses in IUO and assess the helpfulness of ¹⁸ F-fluorodesoxyglucose positron emission tomography with computerized tomography (¹⁸ F-FDG-PET/CT) in the diagnosis strategy.

RESULTS

A total of 317 IUO patients with ¹⁸ F-FDG-PET/CT were enrolled. A diagnosis was reached in 228 patients: noninfectious inflammatory diseases (NIID) (37.5%), infectious diseases (18.6%), malignancies (7.9%), and non-systemic-inflammatory miscellaneous diseases (7.9%). The two leading causes of NIID were polymyalgia rheumatica and giant cell arteritis. ¹⁸ F-FDG-PET/CT results were classified as true positive in 49.8% of patients and contributory in 75.1% of overall IUO patients (after the complete investigation set and a prolonged follow-up). In multivariate analysis, only C-reactive protein minimum level (≥50 mg/L) was associated with the contributory status of ¹⁸ F-FDG-PET/CT.

CONCLUSION

Within the wide spectrum of IUO underlying diseases, ¹⁸ F-FDG-PET/CT is helpful to make a diagnosis and to eliminate inflammatory diseases. Obese patients constitute a specific group needing further studies.

Clinical presentation and treatment response in patients with polymyalgia rheumatica and giant cell arteritis during a 40-week follow-up

Objectives

The aim was to study the clinical features of PMR/GCA and clinical predictors of treatment response during a 40-week follow-up period.

Methods

Clinical data on 77 patients with newly diagnosed PMR/GCA who were treated with oral glucocorticoids were gathered at baseline and during a 40-week follow-up period. A unilateral temporal artery biopsy (TAB) and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET/CT were undertaken at diagnosis. In total, each patient was seen on five occasions (i.e. baseline and weeks 4, 16, 28 and 40). Treatment response was assessed by considering clinical evaluations and results of inflammatory markers.

Results

Of 77 patients [49 (63.6%) female; mean age 71.8 (8.0) years], 64 (83.1%) patients had pure PMR, 10 (13.0%) concomitant PMR and GCA, and 3 (3.9%) pure GCA. The patients reported that clinical symptoms, apart from scalp pain and duration of morning stiffness, improved significantly at week 4 and remained lower at week 40 compared with the relative frequencies at baseline. Besides, all components of physical examination showed significant improvement and remained lower at week 40 compared with the baseline. A complete response was seen in 68.7, 62.9, 44.1 and 33.3% of patients at weeks 4, 16, 28 and 40, respectively. Several clinical features, including female biological sex, younger age, fewer relapses and a lower level of baseline ESR, were significantly associated with a better treatment response. Treatment response during the follow-up period was independent of TAB results and fluorodeoxyglucose uptakes on ¹⁸F-FDG PET/CT at diagnosis.

Conclusion

Obtaining valid disease-specific outcome measures for evaluating treatment efficacy in PMR and GCA that can be applied universally is clearly an unmet clinical need.

Trial registration

ClinicalTrials.gov, https://clinicaltrials.gov, NCT02985424.

Imaging Tests in the Early Diagnosis of Giant Cell Arteritis

Early recognition of giant cell arteritis (GCA) is crucial to avoid the development of ischemic vascular complications, such as blindness. The classic approach to making the diagnosis of GCA is based on a positive temporal artery biopsy, which is among the criteria proposed by the American College of Rheumatology (ACR) in 1990 to classify a patient as having GCA. However, imaging techniques, particularly ultrasound (US) of the temporal arteries, are increasingly being considered as an alternative for the diagnosis of GCA. Recent recommendations from the European League Against Rheumatism (EULAR) for the use of imaging techniques for large vessel vasculitis (LVV) included US as the first imaging option for the diagnosis of GCA. Furthermore, although the ACR classification criteria are useful in identifying patients with the classic cranial pattern of GCA, they are often inadequate in identifying GCA patients who have the extracranial phenotype of LVV. In this sense, the advent of other imaging techniques, such as magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET)/CT, has made it possible to detect the presence of extracranial involvement of the LVV in patients with GCA presenting as refractory rheumatic polymyalgia without cranial ischemic manifestations. Imaging techniques have been the key elements in redefining the diagnostic work-up of GCA. US is currently considered the main imaging modality to improve the early diagnosis of GCA.

Prognostic impacts of glucocorticoid treatment in patients with polymyalgia rheumatica and giant cell arteritis

Identifying comorbidities in polymyalgia rheumatica/giant cell arteritis (PMR/GCA) is crucial for patients' outcomes. The present study aimed to evaluate the impact of the inflammatory process and glucocorticoid treatment on aortic arterial stiffness and body composition in PMR/GCA. 77 patients with newly diagnosed PMR/GCA were treated with oral glucocorticoids and followed for 40 weeks. Aortic pulse wave velocity (PWV) was measured at baseline and during the follow-up period and compared to the results of temporal artery biopsy (TAB) and 18F-FDG PET/CT. Body composition was assessed by total body DXA at baseline and the end of the study. Of 77 patients (49 (63.6%) female, mean of age: (71.8 ± 8.0)), 64 (83.1%) had pure PMR, 10 (13.0%) concomitant PMR and GCA, and 3 (3.9%) pure GCA. Compared to baseline values, aortic PWV was initially decreased at week 16 (p = 0.010) and remained lower than baseline at week 28 (p = 0.002) and week 40 (p < 0.001), with no association with results of TAB and 18F-FDG PET/CT. Aortic PWV was significantly associated with age, male gender, left systolic and diastolic blood pressure, right diastolic blood pressure, and CRP. Total bone mineral content (BMC) was decreased in both genders (p < 0.001), while fat mass (FM) was significantly increased (p < 0.001). However, lean body mass did not significantly change during the study. Changes in FM were correlated with cumulative prednisolone dose (rho: 0.26, p = 0.031). Glucocorticoid treatment of patients with PMR/GCA had several prognostic impacts. Arterial stiffness was decreased due either to the treatment or a reduction in the inflammatory load. Additionally, treatment led to changes in body composition, including a decrease in BMC and FM excess.

Prevalence of Newly Diagnosed Malignancies in Patients with Polymyalgia Rheumatica and Giant Cell Arteritis, Comparison of 18F-FDG PET/CT Scan with Chest X-ray and Abdominal Ultrasound: Data from a 40 Week Prospective, Exploratory, Single Centre Study

The aim of the study was to identify the prevalence of newly diagnosed malignancies in patients with polymyalgia rheumatica (PMR) and giant cell arteritis (GCA), with the aid of 18F-FDG PET/CT scan compared to conventional imaging techniques: Chest X-ray (CXR) and abdominal ultrasound (US). Secondarily, to examine the relative diagnostic accuracy of these two imaging modalities for the detection of cancer. Eighty consecutive patients with newly diagnosed PMR, GCA, or concomitant PMR and GCA, were included and followed up for 40 weeks. All patients underwent an 18F-FDG PET/CT scan, CXR, and abdominal US at diagnosis. Imaging findings were dichotomously categorized into malignant or benign. Among 80 patients, three patients were diagnosed with seronegative rheumatoid arthritis and were excluded from the analysis. Of the remaining 77, 64 (83.1%) patients were diagnosed with pure PMR, 3 (3.9%) with pure GCA, and 10 (13.0%) with concomitant PMR and GCA. Five types of cancer that were more prevalent than the one-year prevalence of 1.2% among the background population were found in four (5.2%; 95%CI: 1.4-12.8%) patients. CXR/abdominal US could detect the solid cancer in one patient, whereas 18F-FDG PET/CT could identify all four solid cancers. Furthermore, four (5.2%; 95%CI: 1.4-12.8%) cases of monoclonal gammopathy of undetermined significance (MGUS) were found. An increase in C reactive protein (CRP) implicated an increased risk for cancer of 2.4% (OR: 1.024, 95%CI: 1.001-1.047; p = 0.041). 18F-FDG PET/CT can reveal occult cancers at an early stage with a high negative predictive value, and it is specifically beneficial in PMR/GCA patients with nonspecific symptoms.