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.

The one-year infection risk among patients diagnosed with giant cell arteritis: use of antibiotics and hospitalisations.

OBJECTIVES: Patients with giant cell arteritis (GCA) primarily have their infections managed by primary care providers and hospitalisation is rarely necessary. Existing studies in GCA focus on infection-related hospitalisations only, whereas the use of antibiotic prescriptions is largely unknown. This study aims to examine the one-year overall infection risk among patients with GCA. METHODS: This nationwide observational cohort study included patients aged ≥50 years with a first-time GCA diagnosis in the Danish National Patient Registry (1996-2022). Patients with GCA were matched 1:10 by sex and date of birth with general population individuals and followed from date of diagnosis. Overall infections were defined as redeemed antibiotic prescriptions or infection-related hospitalisations. Utilising a pseudo-observation approach, we assessed 1-year cumulative incidence proportions (CIP), risk differences (RD), and relative risks (RR) of infections. RESULTS: The study included 17 773 incident patients with GCA and 177 730 reference individuals. Patients with GCA had a 1-year CIP of 52.4% (95% CI: 51.7-53.2) for overall infections and 17.6% (95% CI: 17.1-18.2) for infection-related hospitalisations. Compared with the reference cohort, patients with GCA had a RR of 1.40 (95% CI: 1.38-1.42) for overall infections and 2.71 (95% CI: 2.61-2.82) for infection-related hospitalisations. Additionally, higher cumulative glucocorticoid doses, advanced age (≥70 years), and higher comorbidity were associated with an increased risk of infections among patients with GCA. CONCLUSIONS: The use of antibiotic prescriptions and infection-related hospitalisations in the first year after a GCA diagnosis is high compared with the background population. The cumulative glucocorticoid dose is associated with the infection risk.

A rare case of sarcoid myelitis complicating Löfgren's syndrome.

Neurosarcoidosis is a rare and serious condition. Rapid diagnosis and treatment are crucial to prevent morbidity and mortality. When neurological symptoms are not present at the time of diagnosis, CNS involvement can be undetected. We present a case of neurosarcoidosis complicating Löfgren's syndrome and discus the challenges in diagnostics and treatment, that can be encountered.

An international survey of current management practices for polymyalgia rheumatica by general practitioners and rheumatologists.

OBJECTIVES: To explore current management practices for PMR by general practitioners (GPs) and rheumatologists including implications for clinical trial recruitment. METHODS: An English language questionnaire was constructed by a working group of rheumatologists and GPs from six countries. The questionnaire focused on: 1: Respondent characteristics; 2: Referral practices; 3: Treatment with glucocorticoids; 4: Diagnostics; 5: Comorbidities; and 6: Barriers to research. The questionnaire was distributed to rheumatologists and GPs worldwide via members of the International PMR/Giant Cell Arteritis Study Group. RESULTS: In total, 394 GPs and 937 rheumatologists responded to the survey. GPs referred a median of 25% of their suspected PMR patients for diagnosis and 50% of these were returned to their GP for management. In general, 39% of rheumatologists evaluated patients with suspected PMR >2 weeks after referral, and a median of 50% of patients had started prednisolone before rheumatologist evaluation. Direct comparison of initial treatment showed that the percentage prescribing >25 mg prednisolone daily for patients was 30% for GPs and 12% for rheumatologists. Diagnostic imaging was rarely used. More than half (56%) of rheumatologists experienced difficulties recruiting people with PMR to clinical trials. CONCLUSION: This large international survey indicates that a large proportion of people with PMR are not referred for diagnosis, and that the proportion of treatment-naive patients declined with increasing time from referral to assessment. Strategies are needed to change referral and management of people with PMR, to improve clinical practice and facilitate recruitment to clinical trials.

The provisional OMERACT ultrasonography score for giant cell arteritis.

OBJECTIVES: To develop an Outcome Measures in Rheumatology (OMERACT) ultrasonography score for monitoring disease activity in giant cell arteritis (GCA) and evaluate its metric properties. METHODS: The OMERACT Instrument Selection Algorithm was followed. Forty-nine members of the OMERACT ultrasonography large vessel vasculitis working group were invited to seven Delphi rounds. An online reliability exercise was conducted using images of bilateral common temporal arteries, parietal and frontal branches as well as axillary arteries from 16 patients with GCA and 7 controls. Sensitivity to change and convergent construct validity were tested using data from a prospective cohort of patients with new GCA in which ultrasound-based intima-media thickness (IMT) measurements were conducted at weeks 1, 3, 6, 12 and 24. RESULTS: Agreement was obtained (92.7%) for the OMERACT GCA Ultrasonography Score (OGUS), calculated as follows: sum of IMT measured in every segment divided by the rounded cut-off values of IMTs in each segment. The resulting value is then divided by the number of segments available. Thirty-five members conducted the reliability exercise, the interrater intraclass correlation coefficient (ICC) for the OGUS was 0.72-0.84 and the median intrareader ICC was 0.91. The prospective cohort consisted of 52 patients. Sensitivity to change between baseline and each follow-up visit up to week 24 yielded standardised mean differences from -1.19 to -2.16, corresponding to large and very large magnitudes of change, respectively. OGUS correlated moderately with erythrocyte sedimentation rate, C reactive protein and Birmingham Vasculitis Activity Score (corrcoeff 0.37-0.48). CONCLUSION: We developed a provisional OGUS for potential use in clinical trials.

A nationwide study of ocular manifestations leading to hospital contacts among patients with giant cell arteritis.

OBJECTIVES: To investigate the risk of ocular manifestations leading to hospital contacts among patients with giant cell arteritis (GCA). METHODS: A Danish, nationwide, register-based cohort study including 14,574 GCA patients diagnosed 1996-2018 and 145,740 general population referents, matched on sex and date of birth. Cumulative incidence proportions (CIPs) and relative risks (RRs) of ocular manifestations with 95% confidence intervals (CIs) were calculated using a pseudo-observation approach. RESULTS: A total of 1026/14,574 (7.0%) GCA patients were registered with ocular manifestations within ±1 year of the diagnosis; 392/1026 (38%) being before and 634/1026 (62%) after the GCA diagnosis, and 744/1026 (73%) were registered within ±1 month of the diagnosis. The diagnoses were 336/1026 (33%) retinal vascular occlusions, 300/1026 (29%) disorders of the optic nerve, 177/1026 (17%) visual impairment, 90/1026 (9%) diplopia, and 123/1026 (12%) amaurosis fugax. The CIP for ocular manifestations among GCA patients after 3, 6, and 12 months following the diagnosis were 4.0% (95% CI: 3.6-4.3), 4.2% (95% CI: 3.9-4.6), and 4.6% (95% CI: 4.2-4.9). The 1-year RR of ocular manifestations among GCA patients was 28.0 (95% CI: 24.0-32.7), with age above 70 years, male sex, and a positive temporal artery biopsy being risk factors. Treatment with low-dose aspirin was not associated with a reduced 1-year RR of incident ocular manifestations. CONCLUSIONS: In GCA, most cases of ocular manifestations leading to hospital contacts occur close to the time of diagnosis, with over one-third of cases occurring before the diagnosis, emphasizing the need for early recognition and treatment.

All-cause and cause-specific mortality in patients with giant cell arteritis: a nationwide, population-based cohort study.

OBJECTIVES: To investigate whether GCA is associated with increased all-cause and cause-specific mortality. METHODS: A nationwide, population-based cohort study in Denmark using medical and administrative registries. GCA cases were defined as patients aged ≥50 years from 1996-2018 with a first-time discharge diagnosis of GCA and ≥3 prescriptions for prednisolone within 6 months following diagnosis. Each GCA patient was matched based on age, sex and calendar time to 10 persons without a history of GCA. Index date was the date for the third prednisolone prescription. We used a pseudo-observation approach to calculate all-cause and cause-specific mortality, adjusted risk differences (RDs) and relative risks (RRs). RESULTS: We included 9908 GCA patients and 98 204 persons from the general population. The median time for GCA patients to redeem the third prednisolone prescription was 74 days [interquartile range (IQR: 49-106)]. Among GCA patients, the overall mortality was 6.4% (95% CI: 5.9, 6.9) 1 year after index date and 45% (95% CI: 44, 47) after 10 years. Compared with the reference cohort, adjusted RDs and RRs of deaths in the GCA cohort were 2.2% (95% CI: 1.7, 2.7) and 1.49 (95% CI: 1.36, 1.64) after 1 year, and 2.1% (95% CI: 1.0, 3.3) and 1.03 (95% CI: 1.00, 1.05) 10 years after index date. GCA patients had a higher risk of death due to infectious, endocrine, cardiovascular and gastrointestinal diseases. CONCLUSIONS: GCA is associated with increased all-cause mortality, particularly within the first year following the diagnosis. Cause-specific mortality indicates that mortality in GCA may in part be due to glucocorticoid-related complications.

Increased risk of thoracic aortic complications among patients with giant cell arteritis: a nationwide, population-based cohort study.

OBJECTIVE: To assess the risk of aortic aneurysms (AA), aortic dissections (AD) and peripheral arterial disease (PAD) among patients with GCA. METHODS: In this nationwide, population-based cohort study using Danish national health registries, we identified all incident GCA patients ≥50 years between 1996 and 2018 who redeemed three or more prescriptions for prednisolone. Index date was the date of redeeming the third prednisolone prescription. Case definition robustness was checked through sensitivity analysis. We included general population referents matched 1:10 by age, sex and calendar time. Using a pseudo-observation approach, we calculated 5-, 10- and 15-year cumulative incidence proportions (CIP) and relative risks (RR) of AA, AD and PAD with death as a competing risk. RESULTS: We included 9908 GCA patients and 98 204 referents. The 15-year CIP of thoracic AA, abdominal AA, AD and PAD in the GCA cohort were 1.9% (95% CI 1.5, 2.2), 1.8% (1.4-2.2), 1.0% (0.7-1.2) and 4.8% (4.2-5.3). Compared with the referents, the 15-year RR were 11.2 (7.41-16.9) for thoracic AA, 6.86 (4.13-11.4) for AD, 1.04 (0.83-1.32) for abdominal AA and 1.53 (1.35-1.74) for PAD. Among GCA patients, female sex, age below 70 years and positive temporal artery findings were risk factors for developing thoracic AA. The median time to thoracic AA was 7.5 years (interquartile range 4.4-11.2) with a number needed to be screened of 250 (167-333), 91 (71-111) and 53 (45-67) after 5, 10 and 15 years. CONCLUSION: Patients with GCA have a markedly increased risk of developing thoracic AA and AD, but no increased risk of abdominal AA.

OMERACT definition and reliability assessment of chronic ultrasound lesions of the axillary artery in giant cell arteritis.

OBJECTIVES: To define chronic ultrasound lesions of the axillary artery (AA) in long-standing giant cell arteritis (GCA) and to evaluate the reliability of the new ultrasound definition in a web-based exercise. METHODS: A structured Delphi, involving an expert panel of the Large Vessel Vasculitis subgroup of the Outcome Measures in Rheumatology (OMERACT) Ultrasound Working Group was carried out. The reliability of the new definition was tested in a 2-round web-based exercise involving 23 experts and using 50 still images each from AA of long-standing and acute GCA patients, as well as 50 images from healthy individuals. RESULTS: The final OMERACT ultrasound definition of chronic changes was based on measurement and appearance of the intima-media complex. The overall reliability of the new definition for chronic ultrasound changes in longstanding GCA of the AA was good to excellent with Light's kappa values of 0.79-0.80 for inter-reader reliability and mean Light's-kappa of 0.88 for intra-reader reliability. The mean inter-rater and intra-rater agreements were 86-87% and 92%, respectively. Good reliabilities were observed comparing the vessels with longstanding versus acute GCA with a mean agreement and kappa values of 81% and 0.63, respectively. CONCLUSION: The new OMERACT ultrasound definition for chronic vasculitis of the AA in GCA revealed a good to excellent inter- and intra-reader reliability in a web-based exercise of experts.

Giant cell arteritis: A nationwide, population-based cohort study on incidence, diagnostic imaging, and glucocorticoid treatment.

AIM: The study investigated the development over time of the incidence, diagnostic imaging, and treatment of giant cell arteritis (GCA). METHOD: This nationwide, population-based cohort study was conducted in Denmark using medical and administrative registries. Incident GCA cases from 1996-2018 were defined as patients aged ≥50 years registered with a first-time GCA diagnosis and ≥3 prescriptions for glucocorticoids (GCs) within 6 months after diagnosis. We determined incidence rates of GCA, the proportion of patients still receiving GCs >2 years after diagnosis, the proportion of patients receiving temporal artery biopsies (TAB) and diagnostic imaging including ultrasound, positron emission tomography, magnetic resonance, and/or computed tomography angiography at the time of diagnosis. RESULTS: We identified 9908 incident GCA cases. The incidence rates of GCA remained stable at 19-25 per 100,000 people aged >50 years from 1996-2018. The proportion of GCA patients receiving a TAB remained constant until 2016, after which it promptly declined from 70-80% to 29-39%. In contrast, the proportion of patients receiving diagnostic imaging increased from 2% to 66% from 2000-2018. The proportion of GCA patients remaining in GC treatment has steadily decreased from 1996-2016, but remains high at 64%, 40%, and 34% after 2, 5, and 10 years following the diagnosis, respectively. The cumulative GC dose has remained relatively stable. CONCLUSION: Incidence rates of GCA have remained stable since 1996 despite increasing use of diagnostic imaging. There is a clear discrepancy between current international GCA treatment guidelines and the clinical practice up to 2018.

Positive Predictive Value of the Giant Cell Arteritis Diagnosis in the Danish National Patient Registry: A Validation Study.

PURPOSE: To investigate the positive predictive value (PPV) of the giant cell arteritis (GCA) diagnosis in the Danish National Patient Registry (DNPR). PATIENTS AND METHODS: A total of 293 patients aged ≥50 years with a first-time diagnosis of GCA in the DNPR between January 2012 and December 2017 were included. Patients were sampled from two secondary and one tertiary care hospitals in the Central Region Denmark. Two independent investigators (PH & PT) reviewed all medical files, including medical records, treatment, biochemistry, histopathology and imaging, and either confirmed or dismissed the diagnosis of GCA. In case of disagreement, a consensus agreement was reached. Sub-analyses including number of redeemed prescriptions performed temporal artery biopsies (TABs), and number of GCA-related hospital contacts were performed. RESULTS: We confirmed the diagnosis of GCA in 183/293 patients resulting in a PPV of 62% (95% CI: 57-68). In patients with ≥3 redeemed prescriptions of glucocorticoids (GCs), we confirmed the diagnosis in 166/214 resulting in a PPV of 78% (95% CI: 71-83). In patients with ≥3 redeemed prescriptions of GCs and ≥3 GCA-related hospital contacts, we confirmed the diagnosis in 88/95 resulting in a PPV of 93% (95% CI: 85-96); however, this only included 88/183 confirmed GCA patients. CONCLUSION: This is the first study to validate the diagnostic code of GCA in the DNPR. The overall PPV of GCA in the DNPR was 62%. Requiring redeemed prescriptions of GCs and/or GCA-related hospital contacts increase the PPV, but also excludes a significant number of GCA patients.

Endovascular Treatment of Intracerebral Giant Cell Arteritis.

Background: Giant cell arteritis (GCA) is the most common primary systemic vasculitis predominantly affecting large and medium sized vessels. In rare cases, the vasculitis can affect the vessels of the brain. Results: We describe four cases of GCA with involvement of the cerebral vessels causing stroke. These cases were unresponsive to aggressive immunosuppression and we opted to treat with endovascular balloon dilatation of the stenotic areas. The procedure was safe. The four patients were treated in nine sessions and a total of 16 vessels were treated. We observed two dissections with no clinical influence on the patients. Discussion: In patients with stroke due to progressive GCA that is non-responsive to immunosuppression, endovascular therapy is feasible.

Diagnostic accuracy of ultrasound for detecting large-vessel giant cell arteritis using FDG PET/CT as the reference.

OBJECTIVES: The diagnostic accuracy of axillary artery US in the diagnosis of large-vessel (LV)-GCA using 18F-fluorodeoxyglucose (FDG) PET/CT as reference standard was prospectively evaluated in GCA-suspected patients. As an exploratory analysis, the diagnostic accuracy of cranial artery FDG PET/CT was evaluated. METHODS: Briefly, the inclusion criteria were age ≥50 years, raised inflammatory markers and potential GCA symptoms. Patients in immunosuppressive therapy or with a previous diagnosis of GCA or PMR were excluded. Examinations were performed pre-treatment. LV-GCA reference diagnosis was a clinical diagnosis of GCA and PET-proven LV inflammation. GCA patients fulfilling ACR criteria were considered as cranial-GCA (c-GCA). Patients without GCA were considered controls. Receiver operating characteristic curve analysis of the US-measured axillary intima-media thickness was performed. FDG uptake in temporal, maxillary and vertebral arteries was also assessed. RESULTS: Forty-six patients were diagnosed with LV-GCA, 10 with isolated c-GCA, and in 34 patients GCA was dismissed. Axillary US yielded a sensitivity of 76% and a specificity of 100% for LV-GCA. An axillary intima-media thickness cut-off of 1.0 mm yielded a sensitivity of 74% and a specificity of 92%. Adding LV US to temporal assessment increased sensitivity from 71% to 97% (all GCA patients). Cranial artery PET showed a diagnostic sensitivity of 78% and specificity of 100% for c-GCA. CONCLUSION: Axillary artery US shows high accuracy for the LV-GCA diagnosis. Building upon the recent EULAR recommendations, we propose a diagnostic algorithm with US as the first-line confirmatory test, not only in c-GCA-suspected patients, but in all patients suspected of GCA.

Acetylcholinesterase-associated inflammation in patients with giant cell arteritis. Evaluation by histology and 11C-donepezil PET/CT.

OBJECTIVES: To investigate the in-situ expression of acetylcholinesterase (AChE) in the inflamed vessel wall of patients with biopsy-positive giant cell arteritis (GCA) as compared to biopsy-negative non-GCA patients, and to evaluate the in-vivo expression of AChE in patients with large-vessel GCA (LVGCA) by 11C-donepezil (AChE inhibitor) positron emission tomography/computed tomography (PET/CT). METHODS: Twenty-four biopsy-positive GCA and 44 biopsy-negative non-GCA patients were included for AChE histology. Immunohistochemical methods were used to determine the AChE expression. The histological inflammation and the AChE expression were assessed by an experienced pathologist on a 3-point scale. Two patients with newly diagnosed 18F-fluorodeoxyglucose (18F-FDG) PET/CT verified LVGCA were included for 11C-donepezil PET/CT. PET images were assessed by an experienced nuclear medicine physician. RESULTS: AChE was expressed in all 24 positive temporal artery biopsies, 10/24 showed high AChE expression (grade 2) and 14/24 showed moderate AChE expression (grade 1). No AChE expression was observed outside the media smooth muscle cells (grade 0) in any of the biopsy-negative non-GCA patients. The AChE expression was in 86% agreement with the histological inflammation. The AChE expression was not associated with any clinical or biochemical findings. In both LV-GCA patients, PET/CT revealed extensive vascular FDG uptake but no 11C-donepezil uptake. CONCLUSIONS: AChE is highly expressed in the inflamed vessel wall of patients with GCA. Although, 11C-donepezil PET/CT showed no vascular uptake in the FDG PET/CT verified LV-GCA patients, histological findings raise the possibility that AChE can be used in the development of new diagnostic and disease monitoring tools for GCA.

PR3-ANCA-associated vasculitis is associated with a specific motif in the peptide-binding cleft of HLA-DP molecules.

OBJECTIVES: This study aimed to characterize the association between HLA alleles and ANCA-associated vasculitis (AAV) in a genetically homogeneous population, and to analyse the contribution of specific HLA molecule amino acid sequences to the risk of AAV. METHODS: We included 187 Danish patients with AAV and 1070 healthy controls. All were HLA typed at two-field resolution. The association of HLA alleles to PR3- or MPO-AAV was analysed. The contribution of the dominant molecular motifs of the HLA-DPB1 molecule to the risk of AAV was investigated by association studies that included specific amino acid sequences of the hypervariable regions in exon 2. RESULTS: Ninety-four percent of patients with PR3-AAV were carriers of HLA-DPB1*04:01 while all patients with PR3-AAV were carriers of an HLA-DPB1*04 allele, and 85% were homozygous. This was significantly more than in the control group (P < 0.0001). The association was even stronger when HLA-DPB1*04:02 and -DPB1*23:01 were included. HLA-DPB1*04:01, -DPB1*04:02 and -DPB1*23:01 share amino acids in positions 8-9, 69, 76 and 84-87 within the hypervariable regions, but only positions 69 and 84-87 contributed significantly to the disease risk. HLA-DRB1*15 was associated with an increased risk of developing PR3-AAV, while HLA-DRB1*04, -DRB1*07 and -DQB1*03 were associated with a reduced risk of kidney involvement in PR3-AAV. MPO-AAV was only weakly associated with HLA class I alleles. CONCLUSION: PR3-AAV is strongly associated with the HLA-DPB1 alleles HLA-DPB1*04:01, -DPB1*04:02 and -DPB1*23:01, which share amino acid sequences crucial for the peptide-binding groove.

Simple dichotomous assessment of cranial artery inflammation by conventional 18F-FDG PET/CT shows high accuracy for the diagnosis of giant cell arteritis: a case-control study.

PURPOSE: To estimate the diagnostic accuracy of conventional 18F-FDG PET/CT of cranial arteries in the diagnosis of giant cell arteritis (GCA). METHODS: The study was a retrospective case-control study. The reference diagnosis was fulfillment of the 1990 ACR criteria for GCA. All patients had new-onset GCA. Conventional 18F-FDG PET/CT was performed before glucocorticoid treatment. Controls were age- and sex-matched patients with a previous history of malignant melanoma (MM) undergoing surveillance PET/CT >6 months after MM resection. PET images were evenly cropped to include only head and neck and were assessed in random order by four nuclear medicine physicians blinded to reference diagnosis. Temporal (TA), maxillary (MA) and vertebral (VA) arteries were visually rated for 18F-FDG uptake. Interreader agreement was evaluated by Fleiss kappa. RESULTS: A total of 44 patients and 44 controls were identified. In both groups, the mean age was 69 years (p = 0.45) and 25/44 were women. 35/41 GCA patients were temporal artery biopsy positive (TAB). Considering only FDG uptake in TA and/or MA, diagnostic sensitivity and specificity was 64 and 100%. Including VA, sensitivity increased to 82% and specificity remained 100%. Interreader agreement was 91% and Fleiss kappa 0.82 for the PET diagnosis based on the cranial arteries. CONCLUSION: Conventional 18F-FDG PET/CT is an accurate and reliable tool to diagnose cranial arteritis in glucocorticoid-naïve GCA patients. The high diagnostic specificity suggests that TAB can be omitted in patients with 18F-FDG uptake in cranial arteries. 18F-FDG PET/CT performed in patients with suspected vasculitis should always include the head and neck.

Three days of high-dose glucocorticoid treatment attenuates large-vessel 18F-FDG uptake in large-vessel giant cell arteritis but with a limited impact on diagnostic accuracy.

PURPOSE: To evaluate the in-treatment diagnostic accuracy of FDG PET/CT in large-vessel giant cell arteritis (LV-GCA) by serial scans before and after a short course of high-dose glucocorticoid treatment. METHODS: Twenty-four glucocorticoid-naïve patients with new-onset PET/CT verified LV-GCA (pre-treatment baseline PET) were prospectively included. Excluded were patients with a previous history of GCA or polymyalgia rheumatica, LV-GCA-mimicking conditions and patients on immunosuppressive therapy. All patients were treated with 60 mg of oral prednisolone daily and assigned for in-treatment FDG PET/CT after either 3 (PET3) or 10 days (PET10). Two experienced nuclear medicine physicians, blinded to patients' clinical data, reviewed the FDG PET/CT images. A visual semi-quantitative approach was used. Segmental and homogenous FDG uptake in the wall of the aorta and/or supra-aortic branches with higher uptake intensity than liver was considered consistent with vasculitis. Inter-reader reliability was evaluated. RESULTS: Although glucocorticoid treatment attenuated FDG uptake in large vessels, LV-GCA was accurately diagnosed in 10/10 patients after 3 days of treatment, but only in 5/14 patients after 10 days of treatment (p < 0.001). Interrater reliability was substantial (agreement 87%, Cohen's weighted kappa 0.70). No correlation between CRP and FDG uptake was found. CONCLUSIONS: Within 3 days of high-dose glucocorticoid treatment, FDG PET/CT can diagnose LV-GCA with high sensitivity. This window of opportunity ensures that prompt glucocorticoid treatment can be initiated to avoid debilitating GCA complications with a limited effect on diagnostic accuracy. After 10 days of treatment, FDG PET/CT sensitivity decreases significantly.

[Granulomatosis with polyangiitis - a rare but important differential diagnosis]. / Granulomatose med polyangiitis er en vigtig differentialdiagnose til cancer

Granulomatosis with polyangiitis (GPA) is a rare disease with inflammation in the small vessels. This is a case report of GPA, where lung cancer was initially suspected. A 54-year-old woman eventually developed manifestations from several organ systems, and a diagnosis of GPA was confirmed. Treatment was initiated, but the neurological manifestations proved to be irreversible. This case illustrates that GPA is important to acknowledge, because timely treatment is crucial to reduce mortality and morbidity.

[Diagnostics and treatment of ANCA-associated vasculitis]. / Diagnostik og behandling afANCA-associeret vaskulitis.

The term anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) covers a group of rare diseases with inflammation in the small vessels and associated with the presence of ANCA. The patients can present with signs and symptoms from almost all organs. In primary care as well as in hospitals AAV is important to acknowledge as differential diagnosis to cancer and infectious diseases, because low morbidity and mortality related to AAV is dependent on early diagnosis and timely treatment. Patients suspected of AAV should be finally diagnosed and treated at specialized centres.