The value of [18F]FDG-PET in the diagnosis of large-vessel vasculitis and the assessment of activity and extent of disease

Imaging in vasculitis

PURPOSE OF REVIEW

Systemic vasculitides are characterized by inflammation of blood vessels. Their classification is based on the size of the blood vessels involved - large, medium, or small. Vasculitis early diagnosis and reliable monitoring are crucial to establish a treatment plan and prevent serious complications. Based on these considerations and depending on the location of the affected vessels, the importance of imaging modalities including ultrasonography (US), magnetic resonance Imaging (MRI), magnetic resonance angiography (MRA), computed tomography (CT), computed tomography angiography (CTA), and [18F]-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (FDG-PET/CT) has progressively increased. In addition to physical exam and laboratory data, these imaging tools offer complementary information about vascular changes occurring in vasculitis.This review summarizes the different imaging modalities being utilized to diagnose and monitor vasculitis.

RECENT FINDINGS

The most recent update for the use of imaging in vasculitis is referenced in the 2023 European Alliance of Associations for Rheumatology (EULAR) recommendations and the American College of Rheumatology (ACR) guidelines in 2021. Recent advances in PET imaging in large vessel vasculitis include improved technological imaging acquisition and the use of novel radiotracers for cellular and immune targets. FDG-PET has now been demonstrated to have high sensitivity and specificity to detect temporal arteritis.

SUMMARY

Imaging plays a significant role in the evaluation of vasculitis and continues to gain importance in the diagnosis and monitoring of disease activity. Differences exist between the ACR guidelines, which advocates for temporal artery biopsy, and the EULAR guidelines, which favors imaging modalities for the initial evaluation and diagnosis of large vessel vasculitis (LVV). Prerequisites for appropriate clinical management utilizing imaging in patients with vasculitis are the availability and access to skilled clinicians to interpret the images and the cost of these techniques not being prohibitive.

[Utility of applying a diagnostic algorithm in giant cell arteritis based on the level of clinical suspicion]

INTRODUCTION

To reach the diagnosis of giant cell arteritis (GCA), signs, symptoms, laboratory tests, imaging findings, and occasionally anatomopathological results from temporal artery biopsy are evaluated. This study describes the results of an algorithm analysis based on clinical and ultrasound evaluation of patients with suspected GCA, highlighting its diagnostic utility by contrasting its use in different clinical suspicion scenarios.

METHOD

Prospective multicenter study evaluating patients referred with suspected GCA through a preferential circuit (fast track), grouping them according to low or high clinical suspicion of GCA. Each of these scenarios is evaluated by biopsy and ultrasound for all patients, resulting in positive, indeterminate, or negative outcomes, yielding six possible groups. Potential areas of improvement are explored, emphasizing that, following a negative or indeterminate ultrasound, 18-FDG-PET-CT could be recommended. We analyze the results and application of a diagnostic algorithm, confirming its efficiency and applicability based on whether there is high or low clinical suspicion.

RESULTS

Sixty-nine patients (41 in the high suspicion group and 28 in the low suspicion group). There were 41 new diagnoses of GCA: 35 in the high suspicion group and 6 in the low suspicion group. Using ultrasound alone, the initial algorithm has an overall diagnostic efficiency of 72.5%, which improves to 80.5% when including 18F-FDG-PET/CT. The negative predictive value of ultrasound in patients with low clinical suspicion is 84.6%, and the positive predictive value of ultrasound in patients with high suspicion is 100%, improving sensitivity from 57.1% to 80.8% with 18F-FDG-PET/CT in this scenario. Temporal artery biopsy was performed on all patients, with no differences in sensitivity or specificity compared to ultrasound. In cases where all three tests - ultrasound, biopsy, and 18F-FDG-PET/CT - are performed, sensitivity increases to 92.3% in patients with high clinical suspicion.

CONCLUSION

In situations of high clinical suspicion, the algorithm provides sufficient information for the diagnosis of GCA if ultrasound is positive. A negative ultrasound is sufficient to rule out the diagnosis in the context of low clinical suspicion. 18-FDG-PET-CT may be useful in patients with high suspicion and negative or indeterminate ultrasound results.

Giant-cell arteritis related strokes: scoping review of mechanisms and rethinking treatment strategy?

Stroke is a rare and severe complication of giant cell arteritis (GCA). Although early diagnosis and treatment initiation are essential, the mechanism of stroke is often related to vasculitis complicated by arterial stenosis and occlusion. Its recurrence is often attributed to early steroid resistance or late GCA relapse, so immunosuppressive treatment is often reinforced. However, many questions concerning the mechanisms of stroke remain elusive, and no review to date has examined the whole data set concerning GCA-related stroke. We therefore undertook this scoping review. GCA-related stroke does not necessarily display general signs and inflammatory parameters are sometimes normal, so clinicians should observe caution. Ischemic lesions often show patterns predating watershed areas and are associated with stenosis or thrombosis of the respective arteries, which are often bilateral. Lesions predominate in the siphon in the internal carotid arteries, whereas all the vertebral arteries may be involved with a predominance in the V3-V4 segments. Ultrasonography of the cervical arteries may reveal edema of the intima (halo sign), which is highly sensitive and specific of GCA, and precedes stenosis. The brain arteries are spared although very proximal arteritis may rarely occur, if the patient has microstructural anatomical variants. Temporal artery biopsy reveals the combination of mechanisms leading to slit-like stenosis, which involves granulomatous inflammation and intimal hyperplasia. The lumen is sometimes occluded by thrombi (<15%), suggesting that embolic lesions may also occur, although imaging studies have not provided strong evidence for this. Moreover, persistence of intimal hyperplasia might explain persisting arterial stenosis, which may account for delayed stroke occurring in watershed areas. Other possible mechanisms of stroke are also discussed. Overall, GCA-related stroke mainly involves hemodynamic mechanisms. Besides early diagnosis and treatment initiation, future studies could seek to establish specific preventive or curative treatments using angioplasty or targeting intimal proliferation.

The pentraxin family in autoimmune disease

The pentraxins represent a family of multifunctional proteins composed of long and short pentamers. The latter includes serum amyloid P component (SAP) and C-reactive protein (CRP) whereas the former includes neuronal PTX1 and PTX2 (NPTX1 and NPTX2, respectively), PTX3 and PTX4. These serve as a bridge between adaptive immunity and innate immunity and a link between inflammation and immunity. Similarities and differences between long and short pentamers are examined and their roles in autoimmune disease are discussed. Increased CRP and PTX3 could indicate the activity of rheumatoid arthritis, systemic lupus erythematosus or other autoimmune diseases. Mechanistically, CRP and PTX3 may predict target organ injury, regulate bone metabolic immunity and maintain homeostasis as well as participate in vascular endothelial remodeling. Interestingly, PTX3 is pleiotropic, being involved in inflammation and tissue repair. Given the therapeutic potential of PTX3 and CRP, targeting these factors to exert a beneficial effect is the focus of research efforts. Unfortunately, studies on NPTX1, NPTX2, PTX4 and SAP are scarce and more research is clearly needed to elaborate their potential roles in autoimmune disease.

Imaging increased metabolism in the spinal cord in mice after middle cerebral artery occlusion

Emerging evidence indicates crosstalk between the brain and hematopoietic system following cerebral ischemia. Here, we investigated metabolism and oxygenation in the spleen and spinal cord in a transient middle cerebral artery occlusion (tMCAO) model. Sham-operated and tMCAO mice underwent [18F]fluorodeoxyglucose (FDG)-positron emission tomography (PET) to assess glucose metabolism. Naïve, sham-operated and tMCAO mice underwent multispectral optoacoustic tomography (MSOT) assisted by quantitative model-based reconstruction and unmixing algorithms for accurate mapping of oxygenation patterns in peripheral tissues at 24 h after reperfusion. We found increased [18F]FDG uptake and reduced MSOT oxygen saturation, indicating hypoxia in the thoracic spinal cord of tMCAO mice compared with sham-operated mice but not in the spleen. Reduced spleen size was observed in tMCAO mice compared with sham-operated mice ex vivo. tMCAO led to an increase in the numbers of mature T cells in femoral bone marrow tissues, concomitant with a stark reduction in these cell subsets in the spleen and peripheral blood. The combination of quantitative PET and MSOT thus enabled observation of hypoxia and increased metabolic activity in the spinal cord of tMCAO mice at 24 h after occlusion compared to sham-operated mice.

Time-Related Vascular Inflammatory Response to COVID-19 Assessed by 18F-FDG PET/CT in Follow-Up Tumor Patients

Purpose

This study aimed to assess COVID-19's effects on vascular inflammatory response, by evaluating 18-Fluorodeoxyglucose (¹⁸F-FDG) uptake via positron emission tomography/computed tomography (PET/CT) in the artery of diffuse large B cell lymphoma (DLBCL) patients before and after infection with COVID-19.

Patients and Methods

Thirty-five DLBCL patients administered the chemotherapy regimen R-CHOP and examined by oncological ¹⁸F-FDG PET/CT imaging twice from August 2022 to February 2023 for pre-treatment evaluation or assessment of treatment efficacy were enrolled. Seventeen patients were confirmed with COVID-19 within the study period. Arterial wall FDG uptake was semi-quantitatively analyzed as TBR (target-to-blood pool ratio) in 14 different vascular regions using oncological ¹⁸F-FDG PET/CT. Based on COVID-19 course and the two PET/CT scans, we further analyzed time-related FDG uptake for vascular walls in DLBCL patients with COVID-19.

Results

Arterial TBRs were higher in the last PET/CT examination than previous ones in all patients with or without COVID-19. Besides the ascending aorta, ΔTBR (last PET/CT scanning's TBR minus previous PET/CT scanning's TBR) were not significantly different between the COVID-19 and Control groups. However, cases scanned ≤30 days from infection had remarkably higher ΔTBRs in comparison with those assessed >30 days post-infection in the COVID-19 group (p<0.05). A moderate inverse correlation was observed between ∆Global TBR (last PET/CT scanning's average TBR value minus previous PET/CT scanning's average TBR value) and time distance from COVID-19 onset to ¹⁸F-FDG PET/CT scan (Spearman's rho=-0.591, P=0.012). Interestingly, there were no differences of changes of TBR between different purpose of PET/CT examination group.

Conclusion

This work firstly suggested vascular inflammation is elevated in the early post-COVID-19 phase in DLBCL cases compared with prolonged post-COVID-19 phase or controls. Increasing attention should be paid to these patients and the protection of their vascular function and complications in early COVID-19.

[18F]FDG-PET/CT in Idiopathic Inflammatory Myopathies: Retrospective Data from a Belgian Cohort

[¹⁸F]FDG-PET/CT is a useful tool for diagnosis and cancer detection in idiopathic inflammatory myopathies (IIMs), especially polymyositis (PM) and dermatomyositis (DM). Data deriving from Europe are lacking. We describe [¹⁸F]FDG-PET/CT results in a Belgian cohort with IIMs, focusing on patients with PM and DM. All of the cases of IIMs admitted between December 2010 and January 2023 to the Cliniques Universitaires Saint-Luc (Belgium) were retrospectively reviewed. In total, 44 patients were identified with suspected IIMs; among them, 29 were retained for final analysis. The mean age of the retained patients was 48.7 years; 19 patients were female (65.5%). Twenty-two patients had DM and seven had PM. The mean serum creatinine kinase (CK) and the mean CRP levels were 3125 UI/L and 30.3 mg/L, respectively. [¹⁸F]FDG-PET/CT imaging was performed for 27 patients, detecting interstitial lung diseases (ILDs) in 7 patients (25.9%), cancer in 3 patients (11.1%), and abnormal muscle FDG uptake compatible with myositis in 13 patients (48.1%). All of the patients who were detected to have ILDs via PET/CT imaging were confirmed using a low-dose lung CT scan. Among the patients who were detected to have abnormal muscle FDG uptake via PET/CT scans (13/28), the EMG was positive in 12 patients (p = 0.004), while the MRI was positive in 8 patients (p = 0.02). We further observed that there was a significantly higher level of CK in the group with abnormal muscle FDG uptake (p = 0.008). Our study showed that PET/CT is useful for detecting cancer and ILDs. We showed that the detection of abnormal muscle uptake via PET/CT was in accordance with EMG and MRI results, as well as with the mean CK value, and that the presence of dyspnea was significantly associated with the presence of ILDs detected via PET/CT imaging (p = 0.002).

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Impact of [18F]FDG PET/CT in the Assessment of Immunotherapy-Induced Arterial Wall Inflammation in Melanoma Patients Receiving Immune Checkpoint Inhibitors

We aimed to investigate the role of [¹⁸F]FDG positron emission tomography/computed tomography (PET/CT) in the early detection of arterial wall inflammation (AWI) in melanoma patients receiving immune checkpoint inhibitors (ICIs). Our retrospective study enrolled 95 melanoma patients who had received ICIs. Inclusion criteria were ICI therapy for at least six months and at least three [¹⁸F]FDG PET/CTs, including one pretreatment session plus two scans three and six months after treatment initiation. AWI was assessed using quantitative and qualitative methods in the subclavian artery, thoracic aorta, and abdominal aorta. We found three patients with AWI visual suspicion in the baseline scan, which increased to five in the second and twelve in the third session. Most of these patients' treatments were terminated due to either immune-related adverse events (irAEs) or disease progression. In the overall population, the ratio of arterial-wall maximum standardized uptake value (SUVmax)/liver-SUVmax was significantly higher three months after treatment than the pretreatment scan in the thoracic aorta (0.83 ± 0.12 vs. 0.79 ± 0.10; p-value = 0.01) and subclavian artery (0.67 ± 0.13 vs. 0.63 ± 0.12; p-value = 0.01), and it remained steady in the six-month follow-up. None of our patients were diagnosed with definite clinical vasculitis on the dermatology follow-up reports. To conclude, our study showed [¹⁸F]FDG PET/CT's potential to visualise immunotherapy-induced subclinical inflammation in large vessels. This may lead to more accurate prediction of irAEs and better patient management.

A review on the deeper understanding of inflammation and infection of the thoracic aorta

OBJECTIVE

To review the current literature regarding infection and inflammation of the thoracic aorta and to summarise its aetiologies, pathogenesis and clinical presentation. Additionally, the authors sought to compare diagnostic methods and to analyse the different management options.

METHOD

A comprehensive electronic search using PubMed, MEDLINE, Scopus and Google Scholar was conducted to find relevant journal articles with key search terms including: 'aortitis', 'thoracic aortic infection' and 'surgical management of infected thoracic aortic aneurysms'. Prominent publications from 1995 till present (2021) were analysed to achieve a deeper understanding of thoracic aorta infection and inflammation, and the information was then collated to form this review.

RESULTS

The literature review revealed that infectious causes are more prominent than non-infectious causes, with Gram positive bacteria such as Staphylococcus, Enterococcus and Streptococcus accounting for approximately 60% of the infections. The authors also noted that Staphylococcus Aureus was associated with poorer outcomes. Key diagnostic tools include MRI and multi-slice CT imaging, which are useful imaging modalities in defining the extent of the disease thus allowing for planning surgical intervention. Surgical intervention itself is extremely multifaceted and the rarity of the condition means no large-scale comparative research between all the management options exists. Until more large-scale comparative data becomes available to guide treatment, the optimal approach must be decided on a case-by-case basis, considering the benefits and drawback of each treatment option.

CONCLUSION

A high index of suspicion and a comprehensive history is required to effectively diagnose and manage infection and inflammation of the thoracic aorta. Differentiating between infectious and inflammatory cases is crucial for management planning, as infectious causes typically require antibiotics and surgical intervention. Over the years, the post treatment results have shown significant improvement due to earlier diagnosis, advancement in surgical options and increasingly specific microbial therapy.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Performance of Deauville Criteria in [18F]FDG-PET/CT Diagnostics of Giant Cell Arteritis

In this retrospective study, PET/CT data from 59 patients with suspected giant cell arteritis (GCA) were reviewed using the Deauville criteria to determine an optimal cut-off between PET positivity and negativity. Seventeen standardised vascular regions were analysed per patient by three investigators blinded to clinical information. Statistical analysis included ROC curves with areas under the curve (AUC), Cohen's and Fleiss' kappa (κ) to calculate sensitivity, specificity, accuracy, and agreement. According to final clinician's diagnosis and the revised 2017 ACR criteria GCA was confirmed in 29 of 59 (49.2 %) patients. With a diagnostic cut-off ≥ 4 (highest tracer uptake of a vessel wall exceeds liver uptake) for PET positivity, all investigators achieved high accuracy (range, 89.8-93.2%) and AUC (range, 0.94-0.97). Sensitivity and specificity ranged from 89.7-96.6% and 83.3-96.7%, respectively. Agreement between the three investigators suggested 'almost perfect agreement' (Fleiss' κ = 0.84) A Deauville score of ≥4 as threshold for PET positivity yielded excellent results with high accuracy and almost perfect inter-rater agreement, suggesting a standardized, reproducible, and reliable score in diagnosing GCA. However, the small sample size and reference standard could lead to biases. Therefore, verification in a multicentre study with a larger patient cohort and prospective setting is needed.

The role of PET/CT in large vessel vasculitis and related disorders: diagnosis, extent evaluation and assessment of therapy response

Large vessel vasculitides (LVV) are defined as chronic inflammatory disorders that affect the arteries with two major variants being distinguished: giant cell arteritis (GCA) and Takayasu's arteritis (TAK). These often present with nonspecific constitutional symptoms which makes an accurate diagnosis often challenging. Nevertheless, timely diagnosis is of utmost importance to initiate treatment and to avoid potential life-threatening complications. [¹⁸F]FDG-PET/CT is nowadays widely accepted as useful tool to aid in the diagnosis of large vessel vasculitis. However, its role to monitor disease activity and to predict disease relapse during follow-up is less obvious since vascular [¹⁸F]FDG uptake can be detected in the absence of clinical or biochemical signs of disease activity. In addition to the two major variants, [¹⁸F]FDG-PET/CT has shown promise in (peri-)aortitis and related disorders. This article aims to provide an update on the current knowledge and limitations of [¹⁸F]FDG-PET/CT for the diagnosis and assessment of treatment response in LVV. Furthermore, other radiopharmaceuticals targeting key components of the vascular immune system are being discussed which could provide an interesting alternative to image vascular inflammation in LVV.

Combined modality PET/MR for the detection of severe large vessel vasculitis

Background

Large vessel vasculitis (LVV) can be characterized based on symptom severity, and this characterization helps clinicians decide upon treatment approach. Our aim was to compare the imaging findings of combined modality positron emission tomography/magnetic resonance (PET/MR) and inflammatory markers between severe and non-severe LVV. A retrospective query was performed to identify all patients with LVV who underwent PET/MR at our institution between January 2015 and January 2021.

Results

Eleven patients (nine females; age 62.2 ± 16.4 years) underwent 15 PET/MR scans. Positivity was defined by findings indicative of active LVV on each modality: PET positive if vessel metabolic activity > liver metabolic activity; MR positive if wall thickening or contrast enhancement. When positive PET or positive MR findings were considered a positive scan, LVV patients with severe disease (n = 9 scans) showed a higher number of positive scans (n = 9) compared to the number of positive scans in non-severe patients (n = 3) (p < 0.05). The sensitivity and specificity for the detection of severe LVV were 1.00 and 0.50, respectively. When only the presence of both positive PET and positive MR findings were considered a positive scan, inflammatory marker levels were not significantly different between severe and non-severe LVV groups (severe: erythrocyte sedimentation rate (ESR) = 9.8 ± 10.6 mm/h; C-reactive protein (CRP) = 0.6 ± 0.4 mg/dL) (non-severe: ESR = 14.3 ± 22.4 mm/h; CRP = 0.5 ± 0.6 mg/dL). Blood- and liver-normalized maximum standardized uptake values were not significantly different between severe and non-severe patients (1.4 ± 0.3 vs 1.5 ± 0.4; 1.1 ± 0.4 vs 1.0 ± 0.3, respectively).

Conclusions

Because of the differences observed, PET/MR appears to be better suited to facilitate the characterization of LVV as severe or non-severe compared to inflammatory marker measurements and quantitative measurements of metabolic activity. Qualitative assessment of PET and MR positivity by 18F-fluorodeoxyglucose PET/MR may be able to supplement clinical symptoms-based LVV classification decisions and may be helpful when clinical symptoms overlap with other disease processes.

Distribution patterns of arterial affection and the influence of glucocorticoids on 18F-fluorodeoxyglucose positron emission tomography/CT in patients with giant cell arteritis

Background

Giant cell arteritis (GCA) with the involvement of extracranial vessels is increasingly coming into focus. Isolated aortic involvement in the acute phase of GCA is probably more frequent than estimated because only a minority of patients show typical symptoms. ¹⁸F-fluorodeoxyglucose positron emission tomography/CT (PET/CT) is a reliable imaging tool to diagnose patients with extracranial GCA. The aim of this retrospective study was to quantify arterial involvement at the onset of a newly diagnosed GCA by PET/CT and to evaluate the influence of glucocorticoid (GC) treatment on the diagnostic performance of this imaging technique.

Methods

The study included 60 patients with GCA at the onset of a GCA. All patients had undergone a PET/CT scan. 44 patients were GC naïve and 16 patients received GC.

Results

The most affected arteries were the ascending aorta (72%), followed by the brachiocephalic trunk (62%), aortic arch (60%) and descending aorta (60%). The aorta and its branches showed an inflammatory involvement in 83.3% of patients. A singular affection of the aorta and the brachiocephalic trunk was revealed in 20% of cases. GC-naïve patients (95.5%) had more frequently affected arteries compared with GC-treated patients (50%).

Conclusion

Our study showed the frequent involvement of the thoracic aorta and brachiocephalic trunk in patients with GCA using PET/CT. Since these vascular compartments cannot be visualised by ultrasound, we advocate screening imaging of the aorta with PET/CT when GCA is suspected. Because the use of GC is associated with a marked decrease in the inflamed vascular segment in GCA, PET/CT should be performed as soon as possible.

A Simplified PET/CT Measurement Routine with Excellent Diagnostic Accuracy for the Diagnosis of Giant Cell Arteritis

We previously proposed standard uptake value (SUV) ratio-based cut-off values for [18F] fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) for diagnosing giant cell arteritis (GCA) with high diagnostic accuracy. Here we confirm our findings in an independent cohort and report a simplified procedure for using a SUV ratio to diagnose LV-GCA. Patients with suspected GCA were consecutively included. The ‘peak SUV ratio’ was defined in a two-step approach. First, the vessel with the visually brightest radiotracer uptake in the supra-aortic (SA) and in the aorto-iliofemoral (AIF) region was identified. Here, the maximum SUV of the vessel was measured and divided by the mean SUV of the liver (SUVratio). A ratio >1.0 in the SA or >1.3 in the AIF region was scored as vasculitis. The diagnostic accuracy, sensitivity, and specificity of the ‘peak SUV ratio’ in the SA and AIF region was assessed. From 2015 to 2019, 50 patients (24 female, median age 71 years) with suspicion of GCA were included, 28 patients with GCA and 22 patients with exclusion of GCA. Peak SUV had an AUC of 0.91, a sensitivity of 0.89, and a specificity of 0.73 for diagnosing GCA. Peak SUV accuracy of the AIF arteries was lower (AUC 0.81) than of the SA arteries (AUC 0.95). Our SUV ratio cut-off values for diagnosing GCA are consistently valid, also when applied in a time-efficient clinical procedure focusing on the peak SUV ratio. The diagnostic performance of PET/CT in this validation cohort was even higher, compared to the inception cohort (AUC of 0.83).

Imaging features of 18F-FDG PET/CT in different types of systemic vasculitis

OBJECTIVE

To analyze ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) image features in different types of systemic vasculitis and explore its classification and diagnostic significance for systemic vasculitis.

METHODS

Clinical and ¹⁸F-FDG PET/CT imaging data of 71 consecutive patients (34 males, 37 females, mean age 53.4 ± 20.5 years) who were examined at Peking University People's Hospital and diagnosed with active systemic vasculitis were analyzed retrospectively, and ¹⁸F-FDG PET/CT imaging features of different types of systemic vasculitis were analyzed in patients with positive ¹⁸F-FDG PET/CT findings.

RESULTS

The proportions of large-, medium-, small-, and variable-vessel vasculitis were 36.6%, 15.5%, 29.6%, and 18.3%, respectively, and 93.0% of patients had positive findings on PET/CT, of which 63.6% had vascular involvement and 53.0% had extravascular involvement. Different types of vasculitis had different lesion sites, distribution patterns, and morphological changes. Large-vessel vasculitis mainly affected the aorta and its branches to the head and neck. Takayasu arteritis showed segmental involvement of the vascular and morphological changes of the vessel wall. Giant cell arteritis manifested as diffuse vascular involvement, which usually involved the temporal artery and the abdominal aorta and its branches. Medium-vessel vasculitis polyarteritis nodosa manifested as diffuse vascular involvement of both lower extremities. Small-vessel vasculitis anti-neutrophil cytoplasmic antibody-associated vasculitis manifested as granulomatous inflammation of extravascular regions. Variable-vessel vasculitis Behcet's disease involved both blood vessels and extravascular regions.

CONCLUSION

Different types of systemic vasculitis show characteristic manifestations in ¹⁸F-FDG PET/CT images, which may be useful for the diagnosis and classification of systemic vasculitis.

KEY POINTS

• Determining an early diagnosis of systemic vasculitis may be challenging. • Different types of systemic vasculitis show characteristic manifestations in ¹⁸F-FDG PET/CT images. • ¹⁸F-FDG PET/CT may be useful for the diagnosis and classification of systemic vasculitis.

18F-FDG PET/CT in Late Acquisition Identifies Sites of Active Disease in Treated Takayasu Arteritis

OBJECTIVE

Few studies have taken advantage of 18F-fluorodeoxyglucose positron emission tomography associated with computed tomography (18F-FDG PET/CT) to personalize patient evaluation and identify sites of more active disease in Takayasu arteritis (TA)-treated patients. This study aimed to evaluate the utility of 18F-FDG PET/CT in late acquisition in identifying sites of active disease in patients under full treatment for TA.

METHODS

In this cross-sectional study, patients under full treatment underwent whole-body 18F-FDG PET/CT. Sites of increased 18F-FDG uptake were classified by a score of 3 on the visual scale using the liver uptake as reference. A quantitative analysis was also performed by measuring the maximum standardized uptake value (SUV) of the vascular wall of affected arteries. Disease activity using the National Institutes of Health criteria was also evaluated.

RESULTS

Of the 20 patients, there were 18 female and 2 male patients, with a mean age of 43.6 (±11.58) years and a disease duration of 8.3 (±6.25) years. Thirteen participants (65%) were in inflammatory activity according to the criteria proposed by the National Institutes of Health. All patients received immunosuppressive agents, and one of them received immunobiological treatment. The highest SUV value was 6.2 in the aortic arch, and the lowest was 1.0 in the subclavian artery. The mean maximum SUV did not differ between clinically active and inactive patients. In the visual analysis, all participants had at least 1 vascular site with inflammatory activity, with an uptake ≥2 in relation to the liver. The aortic arch was the most frequently involved site.

CONCLUSIONS

This study showed that 18F-FDG PET/CT in late acquisition is an effective imaging method to assess TA activity even in fully treated patients.

Ultrasound Technologies and the Diagnosis of Giant Cell Arteritis

Giant cell arteritis (GCA) is a primary autoimmune vasculitis that specifically affects medium-sized extracranial arteries, like superficial temporal arteries (TAs). The most important data to be considered for the ultrasound (US) diagnosis of temporal arteritis are stenosis, acute occlusions and “dark halo” sign, which represent the edema of the vascular wall. The vessel wall thickening of large vessels in GCA can be recognized by the US, which has high sensitivity and is facile to use. Ocular complications of GCA are common and consist especially of anterior arterial ischemic optic neuropathies or central retinal artery occlusion with sudden, painless, and sharp loss of vision in the affected eye. Color Doppler imaging of the orbital vessels (showing low-end diastolic velocities and a high resistance index) is essential to quickly differentiate the mechanism of ocular involvement (arteritic versus non-arteritic), since the characteristics of TAs on US do not correspond with ocular involvement on GCA. GCA should be cured immediately with systemic corticosteroids to avoid further visual loss of the eyes.

99mTc-labelled glucosamine in the assessment of systemic sclerosis inflammatory lung disease: a novel inexpensive investigative tool with predictive value

OBJECTIVE

To evaluate the role of 99mTc-labelled glucosamine [99mTc-ECDG] as a clinical biomarker for the early detection of interstitial lung disease (ILD) in systemic sclerosis (SSc).

METHODS

In this prospective pilot study, glucosamine scanning (GS) was performed in 15 SSc patients, with and without ILD. Collected data included patient disease characteristics, autoantibody profile, GS results, high-resolution computerised tomography [HRCT], pulmonary function tests [PFT], and transthoracic echocardiogram [TTE]. Glucosamine results were correlated with patient clinical profile, HRCT, and PFT's findings.

RESULTS

Lung uptake of 99mTc-ECDG was high in 4 patients, moderate in 3, mild in 5, and normal in 3 with SSc, respectively. Of the patients with high and moderate uptake there was a 100% correlation between 99mTc-ECDG uptake and HRCT showing ILD. Of the 5 patients with mild 99mTc-ECDG uptake, 4 patients had aspiration pneumonia, and 1 had early ILD using HRCT. Of the 3 patients with normal 99mTc-ECDG, 2 had normal HRCTs; the third had severe pulmonary arterial hypertension with minimal HRCT changes of ILD. High and moderate 99mTc-ECDG lung uptake predicted abnormal PFT's in 100% of cases. In 3 patients, there was less extensive disease depicted on the 99mTc-ECDG scans than on the HRCT. These patients demonstrated a more favourable outcome than would have been expected from the HRCT scans alone. Mild 99mTc-ECDG lung uptake correlated with abnormal PFT's in 60% of cases. The pattern of 99mTc-ECDG uptake was excellent (100%) at distinguishing metabolically active ILD from aspiration pneumonia. Diffuse uptake was noted in the former and patchy uptake in the latter disease entity.

CONCLUSION

Increased 99mTc-ECDG uptake in scleroderma lung correlated positively with both structural and functional changes. 99mTc-ECDG is a useful adjunct helping elucidate inflammation secondary to aspiration pneumonia and/or other causes of abnormal PFT's.

HLA-B52 allele in giant cell arteritis may indicate diffuse large-vessel vasculitis formation: a retrospective study

Background

This study aimed to identify new characteristics of elderly onset large-vessel vasculitis (EOLVV) by focusing on human leucocyte antigen (HLA) genotype, polymyalgia rheumatica (PMR), and affected vascular lesions observed on positron emission tomography/computed tomography (PET/CT) imaging.

Methods

We retrospectively studied 65 consecutive Japanese patients with large-vessel vasculitis (LVV) who had extracranial vasculitis lesions and underwent PET/CT imaging. PET/CT images were assessed using the semi-quantitative PET visual score of each affected vessel, and the PET vascular activity score (PETVAS) and number of affected vessels were calculated. Subjects were subsequently grouped based on age at onset, superficial temporal artery (STA) involvement, and presence of PMR and compared each group according to HLA genotype. Unsupervised hierarchical cluster analysis was used to identify the patients with similar characteristics in terms of affected vascular lesions detected through PET/CT imaging. The clinical characteristics and PET/CT findings of the population newly identified in this study were examined.

Results

Twenty-seven patients with EOLVV did not meet the American College of Rheumatology 1990 criteria for giant cell arteritis (GCA) and Takayasu arteritis and were considered as unclassified EOLVV (UEOLVV). The unsupervised hierarchical cluster analysis revealed that UEOLVV with PMR and large-vessel GCA (LV-GCA) formed a cluster of LVV with GCA features (i.e., PMR and/or STA involvement) when restricted to patients who were HLA-B52-positive. Patients who were HLA-B52-positive with LVV and GCA features had similar clinical characteristics and patterns of affected vessels and presented with diffuse LVV lesions. HLA-B52-positive patients who had LVV with GCA features also presented with higher PETVAS, more affected vessels, and lower rates of biologics usage and relapse compared to HLA-B52-positive patients with TAK.

Conclusions

Patients who had UEOLVV with PMR had similar characteristics to patients with LV-GCA. Patients who were HLA-B52-positive and had LVV with GCA features presented with diffuse vascular lesions and may comprise a core population of Japanese patients with EOLVV. The findings of HLA-B52 positivity and diffusely affected vessels in patients with EOLVV can be considered as suspicious findings of LV-GCA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02618-4.

Diagnostic Role of 18F-Fluorodeoxyglucose Positron Emission Tomography for the Evaluation of Patients With Inflammation of Unknown Origin

BACKGROUND

Sometimes, the underlying causes of inflammation cannot be established despite meticulous investigation, including medical history, physical examination, laboratory tests, and radiologic procedures. Rheumatologists are often faced with patients whose condition is known as inflammation of unknown origin (IUO). Differential diagnosis of IUO is diverse, and investigation of these cases is challenging and time-consuming.

OBJECTIVE

The study aimed to assess the diagnostic role of positron emission tomography/computed tomography (PET/CT) in the evaluation of patients with IUO.

METHODS

The study sample consisted of 97 adult patients with IUO who have not been previously diagnosed with an infectious, inflammatory, or malignant disease. The necessary data were collected from January 2015 to June 2018 with a 6-month follow-up period. The patients were screened using PET/CT after a specific diagnosis could not be established with detailed laboratory and radiologic evaluations.

RESULTS

A final diagnosis was established at follow-up, and 47 (54%) of the 97 patients had inflammatory diseases, 30 (34.4%) had malignancies, and 10 (11.4%) had infections. Despite meticulous investigation, 10 patients were left undiagnosed in the follow-up. PET/CT aided diagnosis in 59 patients (60.8%), but it was not helpful in 38 patients (39.2%). PET/CT was positive in 30 (63%) of the 47 patients with inflammatory diseases, whose final diagnosis was inflammatory rheumatic disease, as follows: large-vessel vasculitis in 19 patients, polymyalgia rheumatica in 7 patients, and seronegative arthritis or other rare miscellaneous diseases in 4 patients. The sensitivity of PET/CT was 67% with a specificity and diagnostic accuracy of 100% and 71%, respectively.

CONCLUSIONS

Investigation of the underlying etiology of IUO is time-consuming and challenging. PET/CT may help identify the final diagnosis more quickly by locating an obscure inflammatory site; thus, it may reduce the number of unnecessary biopsies, diagnostic time, anxiety, work loss, morbidity, and mortality.

Value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in the evaluation of pulmonary artery activity in patients with Takayasu's arteritis

AIMS

To explore the value of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in the detection of active pulmonary artery (PA) lesions in patients with Takayasu's arteritis (TA).

METHODS AND RESULTS

Consecutive TA patients with PA involvement were prospectively recruited. Clinical activity was assessed according to the National Institutes of Health (NIH) criteria. CT pulmonary angiography (CTPA) or magnetic resonance pulmonary angiography was performed for evaluation of vascular structural characteristics, and mural thickening was considered as radiologically active. A vascular segment with 18F-FDG uptake ≥ liver was considered as PET-active. A total of 38 18F-FDG PET/CT scans were performed in 29 patients. In terms of disease activity, the sensitivity of 18F-FDG PET/CT did not significantly differ from radiological imaging (71.4% vs. 92.9%, P = 0.250), but 18F-FDG PET/CT had higher specificity (91.7% vs. 37.5%, P = 0.001) and accuracy (84.2% vs. 57.9%, P = 0.022). Although the majority of PET-active PA segments (54.9%) showed mural thickening, 14 PA segments with normal structure were also PET-active. 18F-FDG activity did not significantly differ between the PA and aorta in clinically active patients. In addition, 18F-FDG activity of the PA was positively correlated with inflammatory markers. Changes in 18F-FDG activity in PA during follow-up reflected therapeutic effects.

CONCLUSION

18F-FDG PET/CT can effectively evaluate PA activity in TA patients, and its diagnostic performance is superior to radiological imaging. The 18F-FDG activity of PA shows a good correlation with clinical disease status and inflammatory markers and can be used to monitor therapeutic effects.

Home-Based Exercise Training in Childhood-Onset Takayasu Arteritis: A Multicenter, Randomized, Controlled Trial

Introduction

Childhood-onset Takayasu Arteritis (c-TA) is a rare, large-vessel vasculitis seen in children that could predisposing patients to a high risk of mortality. Exercise has the potential to improve overall health in several diseases, but evidence remains scant in c-TA. The main objective of this study was to investigate the safety and potential therapeutic effects of exercise in c-TA.

Methods

This was a 12-week, multicenter, randomized, controlled trial, to test the effects of a home-based, exercise intervention vs. standard of care in c-TA patients in remission. The primary outcomes were arterial inflammation, assessed by [¹⁸F] FDG- PET/MRI and systemic inflammatory markers. Secondary outcomes included, physical activity levels, functionality, body composition, disease-related parameters, and quality of life.

Results

Thirty-seven patients were assessed for eligibility, which represents the total number of c-TA patients being followed by the three specialized medical ambulatory services in Sao Paulo. After exclusions, fourteen c-TA patients (71.4% females) aged 12-25 years were randomly allocated into exercised (n=5) and non-exercised groups (n=9). Exercise did not exacerbate arterial inflammation. In fact, exercised patients had a reduction in the frequency of vessel segments with severe inflammation, whereas the non-exercised patients had an opposite response (P=0.007). Greater improvements in visceral fat, steps per day, functionality and physical component SF-36 were observed in the exercised patients (P ≤ 0.05).

Conclusions

Exercise is safe and may improve visceral fat, physical activity levels, functionality, and physical component SF-36 in c-TA patients. Thus, exercise arises as a novel, evidence-based intervention to improve general health in c-TA.

Clinical Trial Registration

https://www.clinicaltrials.gov/ct2/show/NCT03494062?term=NCT03494062&draw=2&rank=1, identifier NCT03494062.

Application progress of multiple imaging modalities in Takayasu arteritis

Takayasu arteritis (TA) is a chronic, idiopathic, granulomatous large vessel vasculitis of unknown etiology. The clinical manifestations of TA are incredibly variable, mainly depending on the location of the lesions. In the light of its insidious progress and the diversity of clinical manifestations, a substantial proportion of patients might experience a considerable delay in diagnosis, which leads to irreversible malignant complications, highlighting the importance of early diagnosis. There has been accumulating evidence that early identification of disease is pivotal to initiate timely therapy and ameliorate the prognosis. Therefore, this review discusses and summarizes the latest evidence on the application progress of multiple imaging modalities.

2021 American College of Rheumatology/Vasculitis Foundation Guideline for the Management of Giant Cell Arteritis and Takayasu Arteritis

OBJECTIVE

To provide evidence-based recommendations and expert guidance for the management of giant cell arteritis (GCA) and Takayasu arteritis (TAK) as exemplars of large vessel vasculitis.

METHODS

Clinical questions regarding diagnostic testing, treatment, and management were developed in the population, intervention, comparator, and outcome (PICO) format for GCA and TAK (27 for GCA, 27 for TAK). Systematic literature reviews were conducted for each PICO question. The Grading of Recommendations Assessment, Development and Evaluation methodology was used to rate the quality of the evidence. Recommendations were developed by the Voting Panel, comprising adult and pediatric rheumatologists and patients. Each recommendation required ≥70% consensus among the Voting Panel.

RESULTS

We present 22 recommendations and 2 ungraded position statements for GCA, and 20 recommendations and 1 ungraded position statement for TAK. These recommendations and statements address clinical questions relating to the use of diagnostic testing, including imaging, treatments, and surgical interventions in GCA and TAK. Recommendations for GCA include support for the use of glucocorticoid-sparing immunosuppressive agents and the use of imaging to identify large vessel involvement. Recommendations for TAK include the use of nonglucocorticoid immunosuppressive agents with glucocorticoids as initial therapy. There were only 2 strong recommendations; the remaining recommendations were conditional due to the low quality of evidence available for most PICO questions.

CONCLUSION

These recommendations provide guidance regarding the evaluation and management of patients with GCA and TAK, including diagnostic strategies, use of pharmacologic agents, and surgical interventions.

2021 American College of Rheumatology/Vasculitis Foundation Guideline for the Management of Giant Cell Arteritis and Takayasu Arteritis

OBJECTIVE

To provide evidence-based recommendations and expert guidance for the management of giant cell arteritis (GCA) and Takayasu arteritis (TAK) as exemplars of large vessel vasculitis.

METHODS

Clinical questions regarding diagnostic testing, treatment, and management were developed in the population, intervention, comparator, and outcome (PICO) format for GCA and TAK (27 for GCA, 27 for TAK). Systematic literature reviews were conducted for each PICO question. The Grading of Recommendations Assessment, Development and Evaluation methodology was used to rate the quality of the evidence. Recommendations were developed by the Voting Panel, comprising adult and pediatric rheumatologists and patients. Each recommendation required ≥70% consensus among the Voting Panel.

RESULTS

We present 22 recommendations and 2 ungraded position statements for GCA, and 20 recommendations and 1 ungraded position statement for TAK. These recommendations and statements address clinical questions relating to the use of diagnostic testing, including imaging, treatments, and surgical interventions in GCA and TAK. Recommendations for GCA include support for the use of glucocorticoid-sparing immunosuppressive agents and the use of imaging to identify large vessel involvement. Recommendations for TAK include the use of nonglucocorticoid immunosuppressive agents with glucocorticoids as initial therapy. There were only 2 strong recommendations; the remaining recommendations were conditional due to the low quality of evidence available for most PICO questions.

CONCLUSION

These recommendations provide guidance regarding the evaluation and management of patients with GCA and TAK, including diagnostic strategies, use of pharmacologic agents, and surgical interventions.

The diagnostic value of 18F-FDG PET/CT in identifying the causes of fever of unknown origin

BACKGROUND

This study investigated the clinical significance of ¹⁸F-fluorodeoxyglucose positron emission tomography / computed tomography (¹⁸F-FDG PET/CT) in identifying the causes of fever of unknown origin (FUO).

METHODS

Patients with a fever who received an ¹⁸F-FDG PET/CT examination were retrospectively selected. The means of the two groups were compared using an independent-samples t-test.

RESULTS

Among the 89 included patients, 66 were diagnosed using ¹⁸F-FDG PET/CT. The sensitivity, specificity and diagnostic accuracy of ¹⁸F-FDG PET/CT for the diagnosis of patients with FUO were 84.5%, 25.8%, and 64.0%, respectively. The detection rates of ¹⁸F-FDG PET/CT for neoplastic diseases, infectious diseases and non-infectious inflammatory diseases were 100%, 61.3%, and 75%, respectively. The difference in C-reactive protein (CRP) levels between the two groups was statistically significant.

CONCLUSIONS

¹⁸F-FDG PET/CT has great clinical importance in diagnosing and identifying causes of FUO and improves the accuracy of FUO diagnosis when combined with serum CRP levels.

Giant Cell Arteritis: A Systematic Review and Meta-Analysis of Test Accuracy and Benefits and Harms of Common Treatments

This systematic review compares treatment options for patients with giant cell arteritis (GCA) and evaluates the test accuracy of studies used in diagnosing and monitoring GCA. These studies were used to inform evidence-based recommendations for the American College of Rheumatology (ACR)/Vasculitis Foundation (VF) vasculitis management guidelines. A systematic review and search of articles in English in Ovid Medline, PubMed, Embase, and the Cochrane Library was conducted. Articles were screened for suitability, and studies presenting the highest level of evidence were given preference. Three hundred ninety-nine full-text articles addressing GCA questions were reviewed to inform 27 Population, Intervention, Comparison, and Outcome questions. No benefit was found with intravenous glucocorticoids (GCs) compared with high-dose oral GCs in patients with cranial ischemic symptoms (27.4% vs 12.3%; odds ratio [OR] 2.39 [95% confidence interval (CI) 0.75-7.62], [very low certainty of evidence]). Weekly tocilizumab with a 26-week GC taper was superior to a 52-week GC taper in patients achieving remission (risk ratio 4.00 [95% CI 1.97-8.12], [low certainty of evidence]). Non-GC immunosuppressive therapies with GCs compared with GCs alone showed no statistically significant in relapse at 1 year (OR 0.87 [95% CI 0.73-1.04], [moderate certainty of evidence]) or serious adverse events (OR 0.81 [95% CI 0.54-1.20]; [moderate certainty of evidence]). Temporal artery biopsy has a sensitivity of 61% (95% CI 38%-79%) and a specificity of 98% (95% CI 95%-99%) in patients with a clinical diagnosis of suspected GCA. This comprehensive systematic review synthesizes and evaluates the benefits and harms of different treatment options and the accuracy of commonly used tests for the diagnosis and monitoring of GCA.

Takayasu Arteritis: a Systematic Review and Meta-Analysis of Test Accuracy and Benefits and Harms of Common Treatments

Objective

Takayasu’s arteritis (TAK) is a granulomatous large‐vessel vasculitis primarily affecting the aorta and its proximal branches. TAK can be a difficult disease to diagnose and manage given the rarity of the disease as well as current limitations in biomarkers, imperfect imaging modalities, and few randomized controlled trials.

Methods

In developing the American College of Rheumatology/Vasculitis Foundation guideline for the management of TAK, we performed an extensive systematic literature review to guide our recommendations. We included RCTs first. When RCTs were not available, we included observational studies that reported on patient‐important outcomes for the intervention and comparison. When studies with comparative data were not available, we included case series that present patient‐important outcomes for either the intervention or the comparison.

Results

Three hundred forty‐seven articles were included for full review to answer 27 population, intervention, comparison, and outcome questions related to TAK. Ten studies were evaluated that addressed the use of glucocorticoids (GCs), non‐GC nonbiologic therapies, as well as biologics in treating TAK. A total of 33 studies, including 8 comparative studies, were included to determine the test accuracy of commonly available diagnostic tests for TAK.

Conclusion

This comprehensive systematic review synthesizes and evaluates the benefits and harms of different treatment options and the accuracy of commonly used tests for the management of TAK.

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

Objective

To define the proportions of agreement between fluorine‐18‐fluorodeoxyglucose (18F‐FDG) positron emission tomography/computed tomography (PET/CT), clinical diagnosis, and temporal artery biopsy (TAB) in patients with polymyalgia rheumatica (PMR) and giant cell arteritis (GCA). Furthermore, the association of 18F‐FDG PET/CT uptake patterns and clinical presentation of newly diagnosed PMR and GCA was investigated.

Methods

Eighty patients newly suspected of having PMR, GCA, or concomitant PMR and GCA were included and followed for 40 weeks. Every patient underwent an 18F‐FDG PET/CT scan before or within 3 days of initiation of steroids in case of GCA. FDG uptakes in 8 paired articular/periarticular sites and 14 arterial segments were evaluated based on a 4‐point visual grading scale.

Results

Of the 80 patients (female: 50 [62.5%]; mean age ± SD: 72.0 ± 7.9), 64 (80.0%) patients were diagnosed with pure PMR, 3 (3.7%) with pure GCA, and 10 (12.5%) with concomitant PMR and GCA. Additionally, three (3.7%) patients were diagnosed with seronegative rheumatoid arthritis during the follow‐up period. For the diagnosis of PMR, 18F‐FDG PET/CT had a proportion of agreement of 75.3 (64.2‐84.4), compared with clinical diagnosis. When comparing findings of 18F‐FDG PET/CT with TAB, 18F‐FDG PET/CT had a proportion of agreement of 93.0 (84.3‐97.7) in all included patients and 69.2 (38.6‐90.9) in the subgroup of patients with vasculitis. C‐reactive protein was significantly higher in patients with PMR activity on 18F‐FDG PET/CT compared with those without 18F‐FDG PET/CT activity (P value = 0.006).

Conclusions

18F‐FDG PET/CT is a powerful imaging technique in PMR and GCA that was in good agreement with clinical diagnosis and TAB.

State of the art of 18F-FDG PET/CT application in inflammation and infection: a guide for image acquisition and interpretation

AIM

The diagnosis, severity and extent of a sterile inflammation or a septic infection could be challenging since there is not one single test able to achieve an accurate diagnosis. The clinical use of 18F-fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography/computed tomography (PET/CT) imaging in the assessment of inflammation and infection is increasing worldwide. The purpose of this paper is to achieve an Italian consensus document on [¹⁸F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases, such as osteomyelitis (OM), prosthetic joint infections (PJI), infective endocarditis (IE), prosthetic valve endocarditis (PVE), cardiac implantable electronic device infections (CIEDI), systemic and cardiac sarcoidosis (SS/CS), diabetic foot (DF), fungal infections (FI), tuberculosis (TBC), fever and inflammation of unknown origin (FUO/IUO), pediatric infections (PI), inflammatory bowel diseases (IBD), spine infections (SI), vascular graft infections (VGI), large vessel vasculitis (LVV), retroperitoneal fibrosis (RF) and COVID-19 infections.

METHODS

In September 2020, the inflammatory and infectious diseases focus group (IIFG) of the Italian Association of Nuclear Medicine (AIMN) proposed to realize a procedural paper about the clinical applications of [¹⁸F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases. The project was carried out thanks to the collaboration of 13 Italian nuclear medicine centers, with a consolidate experience in this field. With the endorsement of AIMN, IIFG contacted each center, and the pediatric diseases focus group (PDFC). IIFG provided for each team involved, a draft with essential information regarding the execution of [¹⁸F]FDG PET/CT or PET/MRI scan (i.e., indications, patient preparation, standard or specific acquisition modalities, interpretation criteria, reporting methods, pitfalls and artifacts), by limiting the literature research to the last 20 years. Moreover, some clinical cases were required from each center, to underline the teaching points. Time for the collection of each report was from October to December 2020.

RESULTS

Overall, we summarized 291 scientific papers and guidelines published between 1998 and 2021. Papers were divided in several sub-topics and summarized in the following paragraphs: clinical indications, image interpretation criteria, future perspectivess and new trends (for each single disease), while patient preparation, image acquisition, possible pitfalls and reporting modalities were described afterwards. Moreover, a specific section was dedicated to pediatric and PET/MRI indications. A collection of images was described for each indication.

CONCLUSIONS

Currently, [¹⁸F]FDG PET/CT in oncology is globally accepted and standardized in main diagnostic algorithms for neoplasms. In recent years, the ever-closer collaboration among different European associations has tried to overcome the absence of a standardization also in the field of inflammation and infections. The collaboration of several nuclear medicine centers with a long experience in this field, as well as among different AIMN focus groups represents a further attempt in this direction. We hope that this document will be the basis for a "common nuclear physicians' language" throughout all the country.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40336-021-00445-w.

Lymphoma Severity and Type Are Associated With Aortic FDG Uptake by 18F-FDG PET/CT Imaging

Background

There is evidence that metabolic disease burden in lymphoma influences patient outcome. However, the impact of disease severity on the cardiovascular system is unknown.

Objectives

The aim of this study was to examine whether lymphoma is associated with arterial inflammation by investigating the relationship between disease metabolic burden and arterial fluorodeoxyglucose (FDG) uptake.

Methods

Sixty-two chemotherapy-naïve patients with active Hodgkin’s or non-Hodgkin’s lymphoma were matched (2:1) to individual control groups of lymphoma patients previously treated and free of active disease. All groups underwent ¹⁸F-FDG position emission tomography–computed tomography imaging. Disease severity was quantified by metabolic tumor volume (MTV) and total lesion glycolysis corresponding to standardized uptake values (SUVs) ≥41% or ≥2.5 of the maximum SUV within lymphoma regions, and aortic FDG uptake was quantified through the target-to-background ratio (TBR). Inflammatory and disease severity biomarkers were also measured.

Results

MTV and total lesion glycolysis measurements were significantly correlated with inflammatory and disease biomarkers. Aortic TBR was higher in patients with active non-Hodgkin’s lymphoma compared with control subjects (median difference 0.51; 95% confidence interval [CI]: 0.28 to 0.78; p < 0.001). Similarly, patients with active Hodgkin’s lymphoma had higher values of aortic TBR compared with control subjects (median difference 0.31; 95% CI: 0.15 to 0.49; p < 0.001). In addition, aortic TBR was modestly increased in patients with stage III to IV disease compared with those with stage I to II disease (median aortic TBR: 2.23 [interquartile range: 2.01 to 2.54] vs. 2.06 [interquartile range: 1.83 to 2.27; p = 0.050). In multivariable analysis, aortic FDG uptake and MTV_≥2.5 values were independently associated (β = 0.425; 95% CI: 0.189 to 0.662; p = 0.001; R² = 0.208), as were aortic FDG uptake and MTV_≥41% (β = 0.407; 95% CI: 0.167 to 0.649, p = 0.001; R² = 0.191).

Conclusions

Aortic wall FDG uptake is related with disease severity indicative of a possible vascular effect of lymphoma. This work highlights a new potential role of molecular imaging in cardio-oncology for evaluating disease severity and its consequences on the vasculature.

Potential Applications of PET Scans, CT Scans, and MR Imaging in Inflammatory Diseases: Part II: Cardiopulmonary and Vascular Inflammation

Detecting inflammation is among the most important aims of medical imaging. Inflammatory process involves immune system activity and local tissue response. The role of PET with fludeoxyglucose F 18 has been expanded. Systemic vasculitides and cardiopulmonary inflammatory disorders constitute a wide range of diseases with multisystemic manifestations. PET with fludeoxyglucose F 18 is useful in their diagnosis, assessment, and follow-up. This article provides an overview of the current status and potentials of hybrid molecular imaging in evaluating cardiopulmonary and vascular inflammatory diseases focusing on the potential for PET with fludeoxyglucose F 18/MR imaging and PET/CT scans.

18F-FDG PET/CT plays a unique role in the management of Takayasu arteritis patients with atypical manifestations

OBJECTIVE

The present study aimed to evaluate the value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) aiding in diagnosing and evaluating disease activity in Takayasu arteritis (TA) patients with atypical clinical manifestations.

METHODS

A retrospective study of 22 TA patients was conducted. All the participants were classified into two groups. Group one including 12 patients, who did not fulfill American College of Rheumatology (ACR) criteria, were diagnosed by modified Ishikawa criteria. Group two involving ten patients, who did not satisfy the modified Ishikawa criteria or ACR criteria, were clinically diagnosed as TA after panel discussion by a combination of clinical data, excluding other diagnoses. PET/CT results were analyzed using quantitative and qualitative metrics. Disease activity was evaluated using the US National Institutes of Health (NIH) criteria.

RESULTS

In group one, nine patients in active stage and two patients in inactive stage had active FDG uptake. One patient in inactive stage had inactive PET/CT results. In group two, five patients in active stage had active FDG uptake and five patients in inactive stage had inactive FDG uptake with SUVmax values of several vascular lesions slightly lower than livermean in each person. The sensitivity of PET/CT scans for evaluating disease activity was 100.0%, specificity was 75.0%, positive predictive value was 87.5%, and negative predictive value was 100.0% compared to NIH criteria.

CONCLUSIONS

PET/CT plays a unique role in diagnosing these TA with atypical manifestation and assisting in evaluating disease activity. Key Points • Diagnosis of these TA patients with atypical manifestations may be difficult. • PET/CT plays a unique role in diagnosing these TA patients and assisting in evaluating disease activity.

Long-term treatment with tocilizumab in giant cell arteritis: efficacy and safety in a monocentric cohort of patients

Objective

The efficacy of tocilizumab (TCZ) in GCA is supported by two randomized controlled studies, in which TCZ allowed remission to be achieved after 52 weeks of treatment. However, after discontinuation of treatment, half of the patients relapsed. The aim of this study was to analyse the efficacy and safety of long-term treatment with TCZ and the role of fluorodeoxyglucose (FDG)-PET/CT scanning in the follow-up of these patients.

Methods

We collected the clinical data of a monocentric cohort of GCA patients retrospectively.

Results

Thirty-two patients were treated with TCZ [25 males and 7 females; age = 74 (59–81) years]. Most of them achieved and maintained clinical remission (1 month: 69%; 3 months: 91%; 6 months: 96%; 12 months: 100%), with serological and FDG-PET/CT scan improvement and a reduction of concomitant glucocorticoid therapy. Nineteen patients were treated for >52 weeks, and in 13 of them a dose tapering was performed, whereas in 2 cases TCZ was suspended for disease remission. Only two patients relapsed: one during TCZ tapering and one after TCZ discontinuation. Ten cases of mild infections and a case of urinary sepsis were reported; in patients treated for >1 year there was no increase in the incidence of side effects compared with patients treated for <12 months.

Conclusion

In our cohort of patients, we confirmed the efficacy of TCZ in the induction and maintenance of remission of GCA, demonstrating an important steroid-sparing effect and a good safety profile. Long-term treatment seems to prevent relapse of the disease, suggesting that TCZ treatment can be continued for >52 weeks with efficacy and safety.

Fluorodeoxyglucose positron emission tomography/computed tomography in the diagnosis, assessment of disease activity and therapeutic response in relapsing polychondritis

OBJECTIVE

To evaluate 18F-fluorodeoxyglucose (FDG) PET/CT in the assessment of disease activity, extent of the disease and response to therapy in relapsing polychondritis.

METHODS

Twenty-five patients (9 men, 16 women) with a mean age of 38.2 years (s.d. 13.7; range 18-62), diagnosed to have relapsing polychondritis according to Damiani and Levine's modification of McAdam's criteria, who underwent PET/CT examination were included. Ten patients underwent a second PET/CT examination after therapy or during follow-up. Clinical symptoms and auxiliary examination findings were recorded. PET/CT findings were reviewed and correlated with the clinical symptoms.

RESULTS

The major symptoms were aural pain (n = 21), nasal pain (n = 10), stridor (n = 5), cough (n = 9), fever (n = 8) and laryngeal tenderness (n = 8). The initial PET/CT was positive in 23/25 patients. PET/CT revealed involvement of auricular (n = 14), nasal (n = 8), laryngeal (n = 7), tracheobronchial (n = 6) and Eustachian (n = 3) cartilages with a mean maximum standardized uptake value (SUVmax) of 4.1 (s.d. 2.5; range 1.7-12.7). Fair correlation of aural/nasal pain/stridor with FDG avidity of cartilage involvement on PET/CT was noted. The key finding was detection of asymptomatic large airway involvement in seven patients (28%). Re-examination PET in 10 patients revealed complete therapeutic response (n = 5), partial response (n = 1), stable disease (n = 1), progressive disease (n = 1) and disease recurrence (n = 2).

CONCLUSION

FDG PET/CT is a useful tool for the assessment of the disease activity and extent. It identified activity in clinically inaccessible sites that are of clinical significance. It is also useful in assessing treatment response and finding relapse.

18F-Fluorodeoxyglucose PET/Computed Tomography in the Diagnosis and Monitoring of Giant Cell Arteritis

18F-Fluorodeoxyglucose (FDG) PET/computed tomography (CT) is a highly accurate diagnostic tool for large vessel vasculitis (LVV) and is one of the recommended imaging modalities for confirmation of the diagnosis. This article focuses on the role of FDG-PET/CT in LVV diagnosis and disease monitoring, mainly focusing on giant cell arteritis; in particular, the diagnostic accuracy, diagnostic criteria, the potential pitfalls in the interpretation of large vessel FDG uptake, and the clinical indication compared with other imaging modalities are discussed.

Diagnostic Role and Feasibility of 18F-FDG PET for Assessing Takayasu Arteritis: Diagnostic Efficacy of Quantifying 18F-FDG Uptake

Takayasu arteritis (TAK) is classified as large-vessel vasculitis caused by inflammation. It is often difficult to identify on clinical examination, and ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) plays an indispensable role in diagnosing TAK by detecting the location and grade of the inflammatory lesions. The clinical utility of ¹⁸F-FDG PET has been established by clinical evidence, and ¹⁸F-FDG PET was added to the Japanese national health insurance listing in April 2018. In TAK, ¹⁸F-FDG uptake shows typical findings and is easily distinguished, except from physiological uptake. Particularly, the clinical significance of ¹⁸F-FDG PET is that can present not only with stenosis but also without stenosis in the arteries, which means that therapeutic intervention is possible before irreversible stenosis develops in the arteries. Additionally, ¹⁸F-FDG PET has superior diagnostic accuracy because it allows quantitative analysis using the maximum standardized uptake value. The analysis is used for the assessment of disease activity of TAK and can be utilized for therapeutic intervention in case of repeating remission during the follow-up term.

Semiquantitative Interpretation Criteria for Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography in Large-Vessel Vasculitis: Pattern Recognition and Correlation with Polymyalgia Rheumatica

Background

Fluorine-18-fluorodeoxyglucose (¹⁸F-FDG)-positron emission tomography/computed tomography (PET/CT) is emerging as a useful imaging modality in suspected large-vessel vasculitis (LVV), owing to its ability to accumulate at the sites of inflammation within the arterial walls. However, there remains scope for standardization of reporting criteria to ensure reproducibility. Recently, a semiquantitative scoring system called "total vascular score" (TVS) has been suggested as a method to standardize and harmonize FDG PET/CT evaluation in LVV patients. The purpose of this study was to assess the clinical utility of the proposed semiquantitative grading scale in LVV patients.

Materials and Methods

Patients presenting with clinical symptoms of vasculitis, who had undergone a baseline FDG-PET/CT were evaluated. ¹⁸F-FDG uptake in the major vessels was quantified with standardized uptake values (SUVs_max) using four-point scale by three independent nuclear physicians. TVS was calculated based on the calculation of the vascular uptake values with respect to mediastinal blood pool and liver uptake and the number of vessels involved.

Results

A total of 106 PET-positive patients (74 males and 32 females) were evaluated. The most frequently involved vessels were thoracic aorta >abdominal aorta >subclavian arteries with mean SUV_max values of 4.05, 3.12, and 2.70, respectively. Mean TVS was 13.18 ± 3.4 (range 03-19) among 276 involved vessels. TVS showed significant positive correlation with erythrocyte sedimentation rate (r = 0.82; P < 0.005). 18 patients showed periarticular FDG uptake, with shoulder joint being the most commonly involved joint.

Conclusion

The simplified visual and semiquantitative grading scale for interpretation and reporting classification provides better objectivity in diagnosis, communication with referring clinicians, and planning in patients of LVV.

PET Scan: Nuclear Medicine Imaging in Myositis

PURPOSE OF REVIEW

Positron emission tomography (PET) combined with computed tomography (CT) has proven useful as a cancer screening technique in patients with inflammatory myopathy, mainly dermatomyositis. In this review, we focus on advances in this direction and other potential applications of PET/CT in patients with inflammatory myopathy.

RECENT FINDINGS

Cancer screening by PET/CT seems suitable and cost-effective in patients with myositis. It has also shown value as a hybrid technique for diagnosing myositis versus controls and could be of interest for differentiating between polymyositis and sporadic inclusion body myositis. Quantification of muscle activity by PET/CT seems reliable. Preliminary data suggest that it could also be used to diagnose and measure the activity of the disease in the lung. PET/CT should be in the toolbox of physicians managing patients with myositis. The multiple applications of PET/CT include its value for cancer screening, measuring the activity of the disease in muscle, and helping to differentiate between myositis phenotypes. The possibility to diagnose and monitor inflammatory lung activity remains to be demonstrated in well-designed studies.

Clinical symptoms and associated vascular imaging findings in Takayasu's arteritis compared to giant cell arteritis

OBJECTIVE

To compare the presence of head, neck and upper extremity symptoms in patients with Takayasu's (TAK) and giant cell arteritis (GCA) and their association with vascular inflammation assessed by ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) or arterial damage assessed by magnetic resonance angiography (MRA).

METHODS

Patients with TAK and GCA underwent clinical and imaging assessments within 24 hours, blinded to each other. Vascular inflammation was defined as arterial FDG-PET uptake greater than liver by visual assessment. Arterial damage was defined as stenosis, occlusion, or aneurysm by MRA. Clinically reported symptoms were compared with corresponding imaging findings using generalised mixed model regression. Cranial symptoms were studied in association with burden of arterial disease in the neck using ordinal regression.

RESULTS

Participants with TAK (n=56) and GCA (n=54) contributed data from 270 visits. Carotidynia was reported only in patients with TAK (21%) and was associated with vascular inflammation (p<0.01) but not damage (p=0.33) in the corresponding carotid artery. Posterior headache was reported in TAK (16%) and GCA (20%) but was only associated with corresponding vertebral artery inflammation and damage in GCA (p<0.01). Arm claudication was associated with subclavian artery damage (p<0.01) and inflammation (p=0.04) in TAK and with damage in GCA (p<0.01). Patients with an increased burden of damaged neck arteries were more likely to experience positional lightheadedness (p<0.01) or a major central nervous system event (p=0.01).

CONCLUSION

The distribution of symptoms and association with imaging abnormalities differs in patients with TAK and GCA. These findings may help clinicians predict associated FDG-PET and MRA findings based on a specific clinical symptom.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02257866.

Fully integrated 18F-FDG PET/MR in large vessel vasculitis

BACKGROUND

To evaluate the usefulness of [18F] fluorodeoxyglucose (FDG) positron emission tomography (PET)/magnetic resonance (MR) in large vessels vasculitis (LVV) patients.

METHODS

We performed an observational retrospective study based on our records. Images were acquired on a PET/MR scanner using 18F-FDG-PET whole body imaging. For each PET scan, a qualitative analysis and a semi-quantitative measure using the maximum of the standardized uptake value (SUVMax) were performed. SUVMax measurements normalized to the liver uptake were categorized using a grading scale. Vessel's wall thickness (WT) was measured at five fixed points (inferior margin of T5, T9, T12, L3, thickest area-max WT).

RESULTS

23 LVV patients were included, 56.5% giant cells arteritis, 34.8% Takayasu's arteritis and 8.7% isolated aortitis, all Caucasian, mostly females (82%). We considered 32 PET scans for the LVV group (from min. 1 to max. 3 scans/patient) mainly during follow-up (29/32 scans), and 23 PET scans from a control group of non-metastatic malignancies patients. We found higher SUVMax compared to controls, in all sites, irrespective of clinical disease activity. Mean WT resulted higher in patients than in controls but was not correlated to SUVMax. Mean WT positively correlated with age in both cohorts, inversely correlated to disease duration, while no correlation with SUVMax was observed. The concordance between clinically active disease and PET hypermetabolism was poor (K Cohen 0.33).

CONCLUSIONS

PET/MR is a safe imaging technique capable of detecting inflammation in aortic wall. Low radiological exposure of PET/MR should be considered especially in young women receiving follow-up studies.

PET/MRI in large-vessel vasculitis: clinical value for diagnosis and assessment of disease activity

Diagnosis of large vessel vasculitis (LVV) and evaluation of its inflammatory activity can be challenging. Our aim was to investigate the value of hybrid positron-emission tomography/magnetic resonance imaging (PET/MRI) in LVV. All consecutive patients with LVV from the Department of Internal Medicine who underwent PET/MRI were included. Three PET/MRI patterns were defined: (i) "inflammatory," with positive PET (>liver uptake) and abnormal MRI (stenosis and/or wall thickening); (ii) "fibrous", negative PET (≤liver uptake) and abnormal MRI; and (iii) "normal". Thirteen patients (10 female; median age: 67-years [range: 23-87]) underwent 18 PET/MRI scans. PET/MRI was performed at diagnosis (n = 4), at relapse (n = 7), or during remission (n = 7). Among the 18 scans, eight (44%) showed an inflammatory pattern and three (17%) a fibrous pattern; the other seven were normal. The distribution of the three patterns did not differ between patients with Takayasu arteritis (TA, n = 10 scans) and those with giant cell arteritis (GCA, n = 8 scans). PET/MRI findings were normal in 2/10 (20%) TA scans vs. 5/8 (62%) GCA scans (p = 0.3). Median SUVmax was 4.7 [2.1-8.6] vs. 2 [1.8-2.6] in patients with active disease vs. remission, respectively (p = 0.003). PET/MRI is a new hybrid imaging modality allowing comprehensive and multimodal analysis of vascular wall inflammation and the vascular lumen. This technique offers promising perspectives for the diagnosis and monitoring of LVV.

Takayasu arteritis: clinical importance of extra-vessel uptake on FDG PET/CT

Background

[F-18]fluorodeoxyglucose positron emission tomography/computed tomography is routinely used for assessing Takayasu arteritis patients. However, extra-vessel [F^-18]fluorodeoxyglucose uptake has not been evaluated in detail in these patients. We aimed to describe the extent and distribution of extra-vascular [F-18]fluorodeoxyglucose uptake on positron emission tomography/computed tomography in Takayasu arteritis patients. Seventy-three [F-18]fluorodeoxyglucose positron emission tomography/computed tomography scans from 64 consecutive Takayasu arteritis patients (59 women, mean age, 35.4 years; range, 13 to 71 years) and 40 scans from age-matched controls (36 women, mean age, 37.8 years; range, 13 to 70 years) were examined. We graded [F-18]fluorodeoxyglucose uptake in large vessels using a 4-point scale and evaluated extra-vessel findings. Factors correlated with disease activity were examined. We evaluated the relationship between disease activity according to the National Institutes of Health score with extra-vessel findings, as well as other inflammatory markers (e.g., white blood cell count and C-reactive protein level).

Results

Extra-vessel involvement was present in 50 of 73 (68.4%) scans, specifically at the following sites: lymph nodes, 1.4%; thyroid glands, 17.8%; thymus, 11.0%; spleen, 1.4%; vertebrae, 45.2%; and pelvic bones, 9.6%. Takayasu arteritis patients had higher [F-18]fluorodeoxyglucose uptake in the spine (P = 0.03) and thyroid glands (P = 0.003) than did controls; uptake in other regions was comparable between groups. Compared with inactive patients, those with active Takayasu arteritis had a higher number of [F-18]fluorodeoxyglucose uptake sites in the vasculature (P = 0.001). Finally, patients with a National Institutes of Health score of ≥ 1 had significantly higher extra-vascular involvement (P = 0.008).

Conclusions

Extra-vessel [F-18]fluorodeoxyglucose uptake may be present in the context of Takayasu arteritis-related inflammatory processes. Information on extra-vascular [F-18]fluorodeoxyglucose uptake may be useful for detecting and evaluating inflammatory processes when interpreting positron emission tomography/computed tomography scans obtained from Takayasu arteritis patients.