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

F18-FDG PET-CT Findings in Juvenile-Onset Polyarteritis Nodosa: A First Series and Literature Review

Objectives: To investigate the findings associated with juvenile polyarteritis nodosa (PAN) on F18-FluoroDeoxyglucose (FDG), positron emission tomography combined with computed tomography (PET-CT). Methods: Patients diagnosed with juvenile PAN (onset <18 years) who underwent a PET-CT at diagnosis (before therapy) were enrolled. PET-CT images were systematically analyzed to identify abnormal findings associated with PAN. In addition, a systematic literature review was performed to identify previously published cases. Results: Six patients with biopsy-confirmed PAN were identified (age at onset 10-17 years). PET-CT was abnormal in all patients. Patchy muscular and subcutaneous FDG uptake with a symmetric distribution in the lower limbs was present in 4/6 patients. Increased FDG uptake in large arteries was found in 1/6 patients. FDG-avid bone lesions were identified in 2/6; additional MRI and bone biopsy results were consistent with chronic non-infectious osteomyelitis (CNO). Unspecific inflammatory findings (medullar and lymphoid organs hypermetabolism) were present in 6/6; these were the only abnormalities present in 2/6 patients. We found this pattern of PET-CT muscular involvement to differ from juvenile dermatomyositis and septic emboli (n = 7 and 2 patients, respectively). In addition, we identified four previously published cases of juvenile PAN investigated with PET-CT: one with FDG-avid muscular and subcutaneous foci, one with increased uptake in large arteries, and two with nonspecific signs (lymphoid organs hypermetabolism). Conclusions: This is the first series of juvenile PAN investigated with PET-CT. Diffuse, patchy hypermetabolic foci in the muscular and subcutaneous tissue of the lower limbs were the most common findings. These features should lead to suspicion of PAN. Further research is needed to assess the diagnostic value of PET-CT in PAN.

18F-FDG-PET/CT for polymyalgia rheumatica: agreement and diagnostic accuracy of routine PET scan report vs. standardized PMR PET scores

Background

18F-FDG-PET/CT may reveal widespread inflammation of musculoskeletal structures in polymyalgia rheumatica (PMR). Currently, scans are subjectively analysed based on the overall gestalt of the scan. Standardized PET scores may potentially aid the interpretation of the scans for suspected PMR. Here, we compared the agreement and diagnostic accuracy of routine PET scan reports vs. the most validated PET scores for PMR.

Methods

68 consecutive patients with suspected PMR (treatment-naïve, n = 29; already treated, n = 39) undergoing 18F-FDG-PET/CT were included. In glucocorticoid-treated patients, complete tapering was pursued prior to the scan. Conclusions of routine PET scan reports were interpretated by three independent readers as "PMR", "not PMR" or "unclear". The Leuven and Leuven/Groningen scores were determined. Agreement of scan report interpretation, and agreement of routine scan reports and PET scores were determined. Sensitivity and specificity were determined for the routine scan report and the two scores, with the clinical diagnosis established after 6 months follow-up as the reference standard.

Results

A diagnosis of PMR was made in 45/68 patients. Routine scan reports were uniformly rated by all three readers in 54 (78%) cases. Following a consensus meeting, scans were rated as "PMR" in 43 cases, "unclear" in 10 cases and "not PMR" in 15 cases. The routine scan report showed a sensitivity of 82% and specificity of 74%, if "unclear" cases were considered negative for PMR. The Leuven and Leuven/Groningen Scores showed similar diagnostic accuracy. Agreement between the routine scan report and PET scores was good (Cohen's kappa 0.60-0.64), if "unclear" cases were excluded from the analysis. Among 8/10 "unclear" cases, the PMR PET Scores accurately distinguished between PMR/PMR-mimicking inflammatory conditions and non-inflammatory conditions. Agreement and diagnostic accuracy of routine scan reports and PET scores were better among treatment-naïve patients than those that had been treated previously.

Conclusion

Our study reveals that routine PET scan reports for suspected PMR can be interpreted differently between readers. Although the routine PET scan reports and PMR PET scores did not always agree, they demonstrated similar diagnostic accuracy, with the highest accuracy observed in treatment-naive patients. The Leuven and Leuven/Groningen score could especially be helpful for cases in which the nuclear medicine physician is uncertain.

Posterior Scleritis Associated with Late-Onset Takayasu Arteritis: A Case Report

PURPOSE

To describe a rare case of posterior scleritis associated with late-onset Takayasu arteritis.

METHODS

A case report of a 75-year-old female presenting with posterior scleritis, eventually diagnosed with late-onset Takayasu arteritis was described. Several medical evaluation visits were conducted, including ophthalmological and rheumatological follow-up. Multiple diagnostic tests were carried out, and the cornerstones of the treatment were corticosteroids and the IL-6 inhibitor tocilizumab.

RESULTS

The patient was admitted to our hospital's emergency room with right unilateral eyelid edema, chemosis and red eye. She had previously experienced two episodes that were misdiagnosed as preseptal cellulitis. The presence of choroidal folds and the T sign on the ultrasound exam were highly suggestive of posterior scleritis. Later, the patient was diagnosed with Takayasu arteritis, a type of large vessel vasculitis. Treatment with steroids was started, which was later switched to IL-6 inhibitors to achieve better control of the systemic disease.

CONCLUSION

Posterior scleritis is often misdiagnosed, necessitating high clinical suspicion. Multimodal diagnosis is important to establish an accurate diagnosis. Up to 34% of cases may be associated with a systemic disease. This is the first case described in the literature of posterior scleritis associated with late-onset Takayasu arteritis.

Multi-Modality Imaging in Cardio-Rheumatology

PURPOSE OF REVIEW

Our purpose was to discuss the advantages and disadvantages of various noninvasive imaging modalities in the evaluation of cardiovascular disease (CVD) in patients with autoimmune rheumatic diseases (ARDs). The detailed knowledge of imaging modalities will facilitate the diagnosis and follow up of CVD in ARDs.

RECENT FINDINGS

Autoimmune Rheumatic Diseases (ARDs) are characterized by alterations in immunoregulatory system of the body. Although there is great progress in anti-rheumatic treatment, ARD patients are still at a higher risk for reduced life expectancy, compared with the general population, which is mainly due to the high incidence of CVD. Cardiovascular imaging holds the promise of early, noninvasive diagnosis and follow up of these patients. Echocardiography (echo), a cost effective, widely available imaging modality, can provide valuable early information about CVD in ARDs and motivate the use of more sophisticated investigations, if needed. Single Photon Emission tomography (SPECT) gives information about myocardial perfusion, while positron emission tomography (PET) gives information about both myocardial perfusion and inflammation with better spatial resolution and less radiation but at a higher financial cost, compared to SPECT. Computed Tomography Coronary Angiography (CTCA) is a reliable tool to rule out the presence of coronary artery disease, which has high incidence in ARD population. Lastly, Cardiovascular Magnetic Resonance (CMR) can perform function and tissue characterization evaluation in the same scan without using radiation and represents the ideal tool for serial evaluation of ARD patients. Lastly, molecular imaging holds the promise for individualized treatment in various ARDs. Cardiovascular imaging is the modern "stethoscope" of the clinicians and therefore they should be familiar with pro and contra of these modalities in order to achieve the best diagnostic and therapeutic target in ARD patients.

Musculoskeletal magnetic resonance imaging findings support a common spectrum of giant cell arteritis and polymyalgia rheumatica

OBJECTIVES

To investigate the proportion and distribution of contrast enhancement (CE) of musculoskeletal structures with MRI of the thorax/abdomen/pelvis in giant cell arteritis (GCA).

METHODS

CE at 34 musculoskeletal sites was rated with a four-point ordinal scale. Patients were divided into groups with or without glucocorticoid (GC) treatment and with or without symptoms of polymyalgia rheumatica (PMR). Two composite scores were created: an MRI score, including seven sites, and a limited MRI score, including four sites.

RESULTS

Retrospectively, 90 consecutive patients with GCA were included. The population included 54 and 36 patients with and without PMR symptoms, respectively, and 45 (50%) patients were receiving GCs at the time of MRI. CE was found in 90.7% of lumbar spines, 87.5% of the pelvis, 82.2% of shoulder girdles and in 95.6% at any site in patients without GCs. The proportion of patients without and with GCs with at least moderate enhancement was, respectively, 91.1% and 75.6% at ≥1-3 sites, 75.6% and 51.1% at ≥4-6 sites, and 64.4% and 28.9% at ≥7-9 sites. The mean difference between the proportion of pathological CE in patients with and without GCs was 27.4% for synovial sites and 18.3% for periarticular/musculotendinous sites. Both composite scores captured substantial differences between groups, and correlation was very strong between scores.

CONCLUSION

MRI shows CE of musculoskeletal structures typical of PMR in most patients with GCA, supporting the concept of 'GCA-PMR spectrum disease'. Changes are more frequent at periarticular/musculotendinous sites and in the presence of PMR symptoms. A clear response to GCs is evident, less so for periarticular/musculotendinous sites.

18 F-FDG PET/CT in the Evaluation of Polyarteritis Nodosa

ABSTRACT

A 61-year-old man with a medical history of human immunodeficiency virus well controlled on antiretroviral therapy presented for distal sensorimotor symptoms, fatigue, and recurrent fevers. Erythrocyte sedimentation rate and C-reactive protein were both elevated. Antineutrophilic cytoplasmic antibody and antinuclear antibodies were negative. Neurologic imaging workup was unremarkable. 18 F-FDG PET/CT, which was crucial for diagnosis, demonstrated pathological tracer activity throughout the medium-sized vessels with sparing of the aorta. In view of presentation, comorbidities, and imaging findings, polyarteritis nodosa was diagnosed. The patient was treated appropriately with steroids and cyclophosphamide with significant symptomatic improvement.

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.

18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Large-Vessel Vasculitis During Active and Inactive Disease Stages Is Associated with the Metabolic Profile, but Not the Macrophage-Related Cytokines: A Proof-of-Concept Study

Giant cell arteritis (GCA) is an autoimmune/autoinflammatory disease affecting large vessels in patients over 50 years old. The disease presents as an acute inflammatory response with two phenotypes, cranial GCA and large-vessel vasculitis (LV)-GCA, involving the thoracic aorta and its branches. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET-CT) is among the imaging techniques contributing to diagnosing patients with systemic disease. However, its association with soluble inflammatory markers is still elusive. This proof-of-concept study aims to identify novel soluble serum biomarkers in PET/CT-positive patients with LV-GCA and associate them with active (0 months) and inactive disease (6 months following treatment), in sequential samples. The most-diseased-segment target-to-background ratio (TBRMDS) was calculated for 13 LV-GCA patients, while 14 cranial GCA and 14 Polymyalgia Rheumatica patients with negative initial PET/CT scans served as disease controls. Serum macrophage-related cytokines were evaluated by cytometric bead array (CBA). Finally, previously published NMR/metabolomics data acquired from the same blood sampling were analyzed along with PET/CT findings. TBRMDS was significantly increased in active versus inactive disease (3.32 vs. 2.65, p = 0.006). The analysis identified nine serum metabolites as more sensitive to change from the active to inactive state. Among them, choline levels were exclusively altered in the LV-GCA group but not in the disease controls. Cytokine levels were not associated with PET/CT activity. Combining CRP, ESR, and TBRMDS with choline levels, a composite index was generated to distinguish active and inactive LV-GCA (20.4 vs. 11.62, p = 0.001). These preliminary results could pave the way for more extensive studies integrating serum metabolomic parameters with PET/CT imaging data to extract sensitive composite disease indexes useful for everyday clinical practice.

Traditional and Emerging Strategies for Managing Polymyalgia Rheumatica: Insights into New Treatments

Background/Objectives: Polymyalgia Rheumatica (PMR) is an inflammatory condition that primarily affects individuals aged 50 and older, especially in Western countries. Although glucocorticoids are the cornerstone of PMR treatment, these drugs are associated with side effects, making it advisable to use them for the shortest duration possible. However, tapering or discontinuation of glucocorticoids often leads to disease relapses. In this review, we focus on the traditional management of PMR, as well as the potential for therapies that may reduce glucocorticoid use. Special attention is given to the efficacy of biologic agents in PMR management. Methods: A literature review, primarily based on articles published in PubMed, was conducted. In addition to discussing various glucocorticoids and conventional disease-modifying drugs used for the management of isolated PMR, this review specifically focused on the information reported regarding new therapies, with particular emphasis on biologic agents. Results: Prednisone or prednisolone at a dose ranging between 12.5 and 25 mg/day is the agreed-upon treatment for PMR. Due to the side effects associated with prolonged glucocorticoid use and the high frequency of relapses when glucocorticoids are tapered, glucocorticoid-sparing agents have emerged as tools in the management of PMR. Methotrexate has traditionally been the conventional disease-modifying antirheumatic drug (DMARD) unanimously recommended for use in PMR. Other conventional DMARDs, such as leflunomide, have shown promising results but require further study. The use of biologic agents has marked a significant step forward in the management of PMR. While anti-TNF agents failed to provide beneficial effects in isolated PMR, anti-IL-6 receptor agents, such as tocilizumab and sarilumab, have demonstrated efficacy in reducing relapse frequency, lowering the cumulative glucocorticoid burden, and achieving long-term remission of the disease. Other biologic agents, many of which have been used in giant cell arteritis, as well as Janus kinase (JAK) inhibitors, are currently under investigation. Conclusions: Glucocorticoids are the primary treatment for isolated PMR but are associated with comorbidities, especially in patients with pre-existing conditions or frequent relapses. Glucocorticoid-sparing agents, such as methotrexate and biologics, in particular tocilizumab and sarilumab, offer alternatives, improving symptoms and reducing glucocorticoid use. While biologic agents reduce long-term side effects and help achieve disease remission, their use must consider potential side effects and higher costs compared to traditional therapies.

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.

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.

Positron Emission Tomography/Computed Tomography in Polymyalgia Rheumatica: When and for What-A Critical Review

Polymyalgia rheumatica (PMR) is an inflammatory disease common in people aged 50 years and older. This condition is characterized by the presence of pain and stiffness involving mainly the shoulder and pelvic girdle. Besides the frequent association with giant cell arteritis (GCA), several conditions may mimic PMR or present with PMR features. Since the diagnosis is basically clinical, an adequate diagnosis of this condition is usually required. Positron emission tomography/computed tomography (PET-CT) has proved to be a useful tool for the diagnosis of PMR. The use of 18F-FDG-PET imaging appears promising as it provides detailed information on inflammatory activity that may not be evident with traditional methods. However, since PET-CT is not strictly necessary for the diagnosis of PMR, clinicians should consider several situations in which this imaging technique can be used in patients with suspected PMR.

Cardiovascular manifestations of Erdheim-Chester disease: A narrative review with two cases

Erdheim-Chester disease (ECD) is a rare 'L' (Langerhans) group histiocytic neoplasm that affects a multitude of organ systems, causing osteosclerotic bone lesions, periaortic encasement ('coated' aorta), retroperitoneal fibrosis involving kidneys and ureters ('hairy kidney'), and infiltration of the central nervous system. Cardiovascular involvement can occur in up to 70% of patients and is usually found during computed tomography/magnetic resonance imaging evaluation. When present, cardiovascular symptoms can have wide variability in presentation from asymptomatic to pericarditis, fatal cardiac tamponade, myocardial infarction, conduction abnormalities, heart failure, renal artery stenosis, and claudication. Cardiac involvement found on imaging includes right atrial pseudotumor, right atrioventricular groove infiltration, and pericardial effusions. ECD can involve the large- and medium-sized arteries, often seen as periarterial thickening (commonly coating the aorta) with stenosis/occlusion. Although more cardiovascular ECD cases have begun to be published in the literature, more data are needed on the outcomes of these patients, as well as how cardiovascular manifestations respond to treatment of ECD.

Large vessel giant cell arteritis

Giant cell arteritis is the principal form of systemic vasculitis affecting people over 50. Large-vessel involvement, termed large vessel giant cell arteritis, mainly affects the aorta and its branches, often occurring alongside cranial giant cell arteritis, but large vessel giant cell arteritis without cranial giant cell arteritis can also occur. Patients mostly present with constitutional symptoms, with localising large vessel giant cell arteritis symptoms present in a minority of patients only. Large vessel giant cell arteritis is usually overlooked until clinicians seek to exclude it with imaging by ultrasonography, magnetic resonance angiography (MRA), computed tomography angiography (CTA), or [18F]fluorodeoxyglucose-PET-CT. Although the role of imaging in treatment monitoring remains uncertain, imaging by MRA or CTA is crucial for identifying aortic aneurysm formation during patient follow up. In this Series paper, we define the large vessel subset of giant cell arteritis and summarise its clinical challenges. Furthermore, we identify areas for future research regarding the management of large vessel giant cell arteritis.

[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.

FDG-PET/CT for investigation of pyrexia of unknown origin: a cost of illness analysis

BACKGROUND

Our study aims to explore the current utilisation of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in the diagnostic pathway of pyrexia of unknown origin (PUO) and associated cost of illness in a large tertiary teaching hospital in Australia.

METHOD

1257 febrile patients between June 2016 and September 2022 were retrospectively reviewed. There were 57 patients who met the inclusion criteria of "classical PUO", of which FDG-PET/CT was performed in 31 inpatients, 15 outpatients and 11 inpatients did not have an FDG-PET/CT scan. The patient demographics, clinical characteristics and inpatient cost were analysed, together with the diagnostic performance of FDG-PET/CT and impact on clinical management.

RESULT

The mean age, length of stay and total cost of admission were higher for inpatients who received FDG-PET/CT versus those who did not. The median cost per patient-bed-day did not differ between the two groups. Inpatients who received earlier FDG-PET/CTs (≤ 7 days from admission) had shorter length of stays and lower total cost compared to those who received a later scan. A negative FDG-PET/CT scan, demonstrating no serious or life-threatening abnormalities resulted in subsequent discharge from hospital or outpatient clinic in 7/10 (70%) patients. There were 11/40 (28%) scans where ancillary abnormalities were identified, requiring further evaluation.

CONCLUSION

FDG-PET/CT showed high diagnostic accuracy and significant impact on patient management in patients with PUO. FDG-PET/CT performed earlier in admission for PUO was associated with shorter length of stay and lower total cost.

New thresholds in semi-quantitative [18F]FDG PET/CT are needed to assess large vessel vasculitis with long-axial field-of-view scanners

AIM

[18F]FDG PET/CT proved accurate in the diagnostic work-up of large vessel vasculitis (LVV). While a visual interpretation is currently considered adequate, several attempts have been made to integrate it with a semiquantitative evaluation. In this regard, there is the need to validate current or new thresholds for the semiquantitative parameters on long-axial field of view (LAFOV) scanners.

METHODS

We retrospectively evaluated 100 patients (50 with LVV and 50 controls) who underwent [18F]FDG LAFOV PET/CT. Semiquantitative parameters (SUVmax and SUVmean) were calculated for large vessels in 3 districts (supra-aortic [SA], thoracic aorta [TA], and infra-aortic [IA]). Values were also normalized to liver activity (SUVmax/L-SUVmax, and SUVmax/L-SUVmean).

RESULTS

Of the 50 patients diagnosed with LVV, SA vessels were affected in 38 (76%), TA in 42 (84%) and IA vessels in 26 (52%). To-liver normalized values had higher diagnostic accuracy than non-normalized values (AUC always ≥ 0.90 vs. 0.74-0.89). For the SA vessels, best thresholds were 0.66 for SUVmax/L-SUVmax and 0.88 for SUVmax/L-SUVmean; for the TA, 1.0 for SUVmax/L-SUVmax and 1.30 for SUVmax/L-SUVmean; finally, for IA vessels, the best threshold was 0.83 for SUVmax/L-SUVmax and 1.11 for SUVmax/L-SUVmean.

CONCLUSION

LAFOV [18F]FDG-PET/CT is accurate in the diagnostic workup of LVV, but different threshold in semi-quantitative parameters than reported in literature for standard scanners should be considered.

Polymyalgia rheumatica

Polymyalgia rheumatica is an inflammatory disease producing pain and stiffness, mainly in the shoulders and pelvic girdle, in people older than 50 years. Elevation of acute phase reactants is common due to the inflammatory nature of the disease. Since there are no specific diagnostic tests, diagnosis requires the exclusion of other diseases with similar presentations. Imaging has helped to identify the pathological substrate of polymyalgia rheumatica and it is increasingly used to support clinical diagnosis or to detect coexistent giant cell arteritis. Although polymyalgia rheumatica does not clearly impair survival or organ function, it can have a detrimental effect on quality of life. Glucocorticoids at 12·5-25·0 mg prednisone per day are effective in inducing remission in most individuals but, when tapered, relapses occur in 40-60% of those affected and side-effects are common. Assessment of disease activity can be difficult because pain related to common comorbidities such as osteoarthritis and tendinopathies, can return when glucocorticoids are reduced, and acute phase reactants are increased less during flares in individuals undergoing treatment or might increase for other reasons. The role of imaging in assessing disease activity is not yet completely defined. In the search for more efficient and safer therapies, tocilizumab and sarilumab have shown efficacy in randomised controlled trials and additional targeted therapies are emerging. However, judicious risk-benefit balance is essential in applying therapeutic innovations to people with polymyalgia rheumatica.