Coronary Artery Vasculitis and Encasement: Multimodality Imaging Findings and Mimics.

Coronary artery vasculitis (CAV) and coronary artery encasement are rarely diagnosed conditions that are important diagnostic considerations, particularly in patients with acute coronary syndrome without traditional cardiovascular risk factors or systemic illness. Vasculitis refers to inflammation of the blood vessel walls, which can be primary or secondary. This process should be distinguished from neoplastic involvement of the coronary arteries, termed coronary artery encasement. Prospective diagnosis of these diseases is challenging, often requiring multidisciplinary workup with careful attention to clinical presentation and multiorgan findings. While CAV and coronary artery encasement can be indistinguishable at coronary CT angiography, certain imaging features help order the differential diagnosis. CAV should be considered when there is smooth wall thickening that is circumferential and/or continuous. A diagnosis of coronary artery encasement is favored when there is irregular or nodular wall thickening that is eccentric to the vessel lumen. Epicardial fat stranding may also appear more extensive compared with CAV. Potential mimics of CAV include atherosclerosis, acute plaque rupture, coronary artery aneurysm, and spontaneous coronary artery dissection. Detection and diagnosis of CAV may help avoid complications related to accelerated atherosclerosis and infarction. Radiologists should be familiar with the range of pathologic conditions that can affect the coronary arteries beyond atherosclerosis as they may be the first to raise such diagnostic possibilities, guiding next steps in patient workup and management. ©RSNA, 2024 Supplemental material is available for this article.

Imaging Challenges and Developments in Large-vessel Vasculitis.

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

Insight into paraneoplastic vasculitis associated with adenocarcinoma colon on F18-FDG PET-CT.

Paraneoplastic vasculitis is a rare entity usually seen in haematological malignancies. Its incidence is even more rare in solid tumours like breast, renal, colon and lung. F-18 FDG PET-CT is commonly used to differentiate between active vasculitis and atherosclerosis in patients with large to medium vessel vasculitis. We present a case of moderately differentiated adenocarcinoma colon presenting for the assessment of with paraneoplastic vasculitis.

[Diagnostic capabilities of spinal MR-angiography and spinal MR-tractography in Foix-Alajouanine syndrome]. / Diagnosticheskie vozmozhnosti spinal'noi MR-angiografii i spinal'noi MR-traktografii pri sindrome Fua­Alazhuanina.

The Foix-Alajouanine syndrome was originally reported by these authors in 1926, as rapidly progressive vasculitis on the background of a viral infection. The pathology was represented by the huge, more than 10 times, dilation either of the lumen, or the walls of the spinal vessels, either of the arteries, or the veins. There were no signs of thrombosis, no malformations. Massive necrosis was observed in the spinal cord. Though plenty of observations of the syndrome were reported over the past 100 years, most of them deal with arteriovenous malformations and/or thrombosis, which had not been revealed originally. We present the case of spinal viral vasculitis detected by means of spinal MR-angiography. The undoubted viral etiology of vasculitis allows us to attribute this observation to Foix-Alajouanine syndrome.

18F-FDG-PET/MR imaging to monitor disease activity in large vessel vasculitis.

Disease-monitoring in large vessel vasculitis (LVV) is challenging. Simultaneous 18F-fluorodeoxyglucose positron emission tomography with magnetic resonance imaging (PET/MRI) provides functional assessment of vascular inflammation alongside high-definition structural imaging with a relatively low burden of radiation exposure. Here, we investigate the ability of PET/MRI to monitor LVV disease activity longitudinally in a prospective cohort of patients with active LVV. We demonstrate that both the PET and MRI components of the scan can distinguish active from inactive disease using established quantification methods. Using logistic-regression modelling of PET/MRI metrics, we devise a novel PET/MRI-specific Vasculitis Activity using MR PET (VAMP) score which is able to distinguish active from inactive disease with more accuracy than established methods and detects changes in disease activity longitudinally. These findings are evaluated in an independent validation cohort. Finally, PET/MRI improves clinicians' assessment of LVV disease activity and confidence in disease management, as assessed via clinician survey. In summary, PET/MRI may be useful in tracking disease activity and assessing treatment-response in LVV. Based on our findings, larger, prospective studies assessing PET/MRI in LVV are now warranted.

Ways to think about vasculitic neuropathy.

PURPOSE OF REVIEW: Vasculitis as a pathomechanism for neuropathy can be isolated to the peripheral nervous system, a part of a systemic autoimmune condition or a component of another syndrome. This review aims to discuss the broad range of diagnoses in which vasculitic neuropathy can be encountered, highlight the progress in imaging techniques in identifying vasculitis, and the new drugs developed for other autoimmune diseases that may be applied to neurological conditions. RECENT FINDINGS: Advances in imaging modalities, ultrasound, MRI and FDG-PET scanning for neuromuscular applications has redefined many aspects of vasculitic neuropathies. The benefit of dividing vasculitides by vessel size is becoming less absolute as diagnostic approaches advance. MRI and FDG-PET are widely used in diagnosis, defining extent of involvement of disease and monitoring. In neuralgic amyotrophy, the identification of hourglass-like constrictions on imaging has changed the treatment paradigm to include surgical interventions. These diagnostic approaches are supported by new immunomodulating and immunosuppression techniques. SUMMARY: Vasculitic neuropathies are a broad group of conditions with a range of causes and associations. Increased use of imaging techniques impacts our traditional definitions and classifications. The growth in treatment options for other autoimmune conditions are likely to infiltrate the neurological landscape.

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

OBJECTIVE: Systematic review of current evidence to analyze the prevalence of extracranial large vessel vasculitis (LVV) using 18F-FDG PET/CT in patients with polymyalgia rheumatica (PMR) or giant cell arteritis (GCA). MATERIALS AND METHODS: PubMed and EMBASE were searched and the results were screened by two reviewers. Study quality was assessed using a modified version of the Newcastle-Ottawa scale. Heterogeneity between studies was assessed using the I2 statistic and the Q test. Further subgroup analyses were performed by disease type, study quality, and 18F-FDG PET/CT uptake criteria. Publication bias was assessed by funnel plot and Egger's test. RESULTS: 268 publications were identified, of which 17 met the selection criteria and were included in the meta-analysis. The overall pooled prevalence of extracranial LVV by 18F-FDG PET/CT was 54.5% [95% CI: 42.6%-66.1%]. In patients with GCA the prevalence was significantly higher than in patients with PMR (60.1% vs. 41.8%, P = 0.006). Likewise, studies with a lower risk of bias reported a higher prevalence of extracranial LVV (61.1% vs. 46.9%; P = 0.010). No publication bias was observed. CONCLUSIONS: The 18F-FDG PET/CT test may be useful in the detection of extracranial LVV, both in patients with PMR or GCA. Such involvement is more frequent in patients with GCA, and may vary depending on the quality of the studies.

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

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

Pulmonary embolism versus pulmonary vasculitis in Hughes-Stovin syndrome: Characteristic computed tomography pulmonary angiographic findings and diagnostic and therapeutic implications. HSS International Study Group.

BACKGROUND AND AIM: Hughes-Stovin syndrome (HSS) is a rare systemic vasculitis with widespread venous/arterial thrombosis and pulmonary vasculitis. Distinguishing between pulmonary embolism (PE) and in-situ thrombosis in the early stages of HSS is challenging. The aim of the study is to compare clinical, laboratory, and computed tomography pulmonary angiography (CTPA) characteristics in patients diagnosed with PE versus those with HSS. METHODS: This retrospective study included 40 HSS patients with complete CTPA studies available, previously published by the HSS study group, and 50 patients diagnosed with PE from a single center. Demographics, clinical and laboratory findings, vascular thrombotic events, were compared between both groups. The CTPA findings were reviewed, with emphasis on the distribution, adherence to the mural wall, pulmonary infarction, ground glass opacification, and intra-alveolar hemorrhage. Pulmonary artery aneurysms (PAAs) in HSS were assessed and classified. RESULTS: The mean age of HSS patients was 35 ± 12.3 years, in PE 58.4 ± 17 (p < 0.0001). Among PE 39(78 %) had co-morbidities, among HSS none. In contrast to PE, in HSS both major venous and arterial thrombotic events are seen.. Various patterns of PAAs were observed in the HSS group, which were entirely absent in PE. Parenchymal hemorrhage was also more frequent in HSS compared to PE (P < 0.001). CONCLUSION: Major vascular thrombosis with arterial aneurysms formation are characteristic of HSS. PE typically appear loosely-adherent and mobile whereas "in-situ thrombosis" seen in HSS is tightly-adherent to the mural wall. Mural wall enhancement and PAAs are distinctive pulmonary findings in HSS. The latter findings have significant therapeutic ramifications.

MR Vessel Wall Imaging for Atherosclerosis and Vasculitis.

Conventional imaging modalities, such as computed tomography angiography, MR angiography, transcranial Doppler ultrasonography, and digital subtraction angiography, are utilized in evaluating intraluminal or intravascular pathology of the intracranial vessels. Limitations of luminal imaging techniques can lead to inaccurate diagnosis, evaluation, and risk stratification, as many cerebrovascular pathologies contain an extrinsic vessel wall component. Furthermore, vessel wall imaging can provide information regarding extent, treatment response, and biopsy targets for vasculitis cases. Overall, while vessel wall imaging can provide robust data regarding intracranial pathologies, further prospective, multicenter studies are required to improve diagnostic application and accuracy.

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

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

Neuroimaging Scoring Tools to Differentiate Inflammatory Central Nervous System Small-Vessel Vasculitis: A Need for Artificial Intelligence/Machine Learning?-A Scoping Review.

Neuroimaging has a key role in identifying small-vessel vasculitis from common diseases it mimics, such as multiple sclerosis. Oftentimes, a multitude of these conditions present similarly, and thus diagnosis is difficult. To date, there is no standardized method to differentiate between these diseases. This review identifies and presents existing scoring tools that could serve as a starting point for integrating artificial intelligence/machine learning (AI/ML) into the clinical decision-making process for these rare diseases. A scoping literature review of EMBASE and MEDLINE included 114 articles to evaluate what criteria exist to diagnose small-vessel vasculitis and common mimics. This paper presents the existing criteria of small-vessel vasculitis conditions and mimics them to guide the future integration of AI/ML algorithms to aid in diagnosing these conditions, which present similarly and non-specifically.

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

AIM: [18F]FDG PET/CT proved accurate in the diagnostic work-up of large vessel vasculitis (LVV). While a visual interpretation is currently considered adequate, several attempts have been made to integrate it with a semiquantitative evaluation. In this regard, there is the need to validate current or new thresholds for the semiquantitative parameters on long-axial field of view (LAFOV) scanners. METHODS: We retrospectively evaluated 100 patients (50 with LVV and 50 controls) who underwent [18F]FDG LAFOV PET/CT. Semiquantitative parameters (SUVmax and SUVmean) were calculated for large vessels in 3 districts (supra-aortic [SA], thoracic aorta [TA], and infra-aortic [IA]). Values were also normalized to liver activity (SUVmax/L-SUVmax, and SUVmax/L-SUVmean). RESULTS: Of the 50 patients diagnosed with LVV, SA vessels were affected in 38 (76%), TA in 42 (84%) and IA vessels in 26 (52%). To-liver normalized values had higher diagnostic accuracy than non-normalized values (AUC always ≥ 0.90 vs. 0.74-0.89). For the SA vessels, best thresholds were 0.66 for SUVmax/L-SUVmax and 0.88 for SUVmax/L-SUVmean; for the TA, 1.0 for SUVmax/L-SUVmax and 1.30 for SUVmax/L-SUVmean; finally, for IA vessels, the best threshold was 0.83 for SUVmax/L-SUVmax and 1.11 for SUVmax/L-SUVmean. CONCLUSION: LAFOV [18F]FDG-PET/CT is accurate in the diagnostic workup of LVV, but different threshold in semi-quantitative parameters than reported in literature for standard scanners should be considered.

Small fetal thymus and adverse perinatal outcome in maternal vasculitis: A prospective case-control study.

BACKGROUND: Ultrasonographic evaluation of fetal thymus size may be used to predict the adverse perinatal outcome in pregnant women with vasculitis. AIM: To compare fetal thymus size in pregnant women with vasculitis and healthy pregnant women and to evaluate whether fetal thymus size predicts the adverse perinatal outcome. METHODS: Twenty-two pregnant women with previously diagnosed vasculitis, 18 of them with Behçet's disease, three with Takayasu arteritis, and one with Wegener's granulomatosis, were included in the case group. The control group comprised 66 healthy pregnant women whose gestational ages matched the case group. Thymic thoracic ratio (TTR) was measured to assess fetal thymus size in the view of three vessels and trachea. RESULTS: In the case group, fetal TTR was significantly lower (0.32 ± 0.03 vs. 0.36 ± 0.02, p = < 0.001). Fetal TTR was significantly lower in those using prednisone than those not (p = .001) in the case group. There was no significant difference in fetal TTR between colchicine used and not used (p = .078) in the case group. Also, for the TTR, a sensitivity of 100% and a specificity of 92% were achieved with a cut-off value of 0.33 for predicting adverse perinatal outcomes. CONCLUSION: The fetuses of pregnant women with maternal vasculitis had a smaller TTR. The small fetal thymus may alert clinicians to possible adverse perinatal outcomes and, with other supporting risk factors, may help predict adverse perinatal outcomes in pregnant women with vasculitis.

VEXAS Syndrome With Tracheal Involvement but Absence of Vasculitis in FDG PET/CT.

ABSTRACT: In early 2022, a 77-year-old man presented with weight loss and recurrent subfebrile temperatures since 6 months. Workup with CT revealed a lung infiltrate. Despite antibiotic treatment, serum inflammation markers remained high. The patient further developed eczematous skin changes, uveitis (sequentially on both eyes), and macrocytic anemia. Finally, an autoinflammatory disease was suspected, and FDG PET/CT was performed. The examination revealed metabolically active foci in several tissues (tracheal cartilage, bone marrow, muscles). Bone marrow aspiration revealed an UBA1 mutation, which is pathognomonic for VEXAS syndrome.

Advanced molecular imaging in large-vessel vasculitis: Adopting FDG-PET into a clinical workflow.

The use of fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging to detect vascular inflammation is increasingly common in the clinical management of patients with large-vessel vasculitis (LVV). In this review, the role of FDG-PET imaging to diagnose and monitor vascular disease activity will be detailed. Suggestions on incorporation of FDG-PET imaging into a clinical workflow will be provided with emphasis on patient preparation, image acquisition, and image interpretation. If FDG-PET imaging is obtained, multimodal imaging assessment, whereby FDG-PET imaging and non-invasive angiography are obtained concurrently, and correlation of imaging findings with clinical assessment is generally advisable. Considering the clinical scenario and treatment status of the patient is important when interpreting vascular FDG-PET image findings.

Systemic Neoplastic Cryoglobulinemic Vasculitis Mimics Large Vessel Occlusion: A Case Report.

INTRODUCTION: We describe a systemic neoplastic cryoglobulinemic vasculitis presenting as a large vessel occlusion (LVO) syndrome. We focus on a rare presentation of a rare condition. CASE REPORT: A 68-year-old man was admitted to the Stroke Unit of Padova with a right middle cerebral artery syndrome. A cerebrovascular event was suspected and protocol for revascularization treatment was performed. Neuroimaging provided no evidence for infarcted tissue or medium-large vascular occlusion but hypothesized a vasculitic involvement of the small vessels of the right hemisphere. Further diagnostics demonstrated a microangiopathic involvement of the heart, kidneys, and lungs. Blood tests showed circulating cryoglobulins and further hematological investigation identified a chronic lymphatic leukemia-like lymphoproliferative disorder. High-dose steroid therapy improved the patient's clinical status and no neurological symptoms remained at discharge. CONCLUSION: We discuss the clinical-radiologic presentation of a small vessel vasculitis that mimics an LVO stroke. This case focuses on the relevance of concomitant multiorgan manifestations in the hyper-acute evaluation of LVO stroke, suggesting the clinical neurologist should consider alternative etiologies as these could provide important clinical implications.

Incidental findings on FDG-PET/CT in large vessel vasculitis.

This study aims to determine the number and type of incidental findings detected on positron emission tomography (PET)/CT in a cohort of patients with large vessel vasculitis (LVV). Reports from PET/CT studies along with the medical charts of a cohort of patients with LVV from a Rheumatology clinic in Edmonton, Alberta, Canada, were retrospectively reviewed. Incidental findings from PET/CT, along with follow-up studies and their diagnosis were documented. The data was analyzed with descriptive statistics. The disease activity of 40 patients, with an average age of 65.8 years, was investigated using PET/CT. A statistically significant increase in incidental findings with age was observed. A total of 61 incidental findings were found in 26 (65%) patients. Of these findings, 25 were in the abdomen and pelvis. The most common incidental finding was lymphadenopathy. Follow-up investigations of incidental findings lead to 5 clinically significant findings including metastatic adenocarcinoma, Mycobacterium avium infection, papillary thyroid carcinoma, pheochromocytoma, and stroke. PET/CT is a reliable tool for determining disease activity in LVV patients and the implications of incidental findings need to be discussed with patients by the ordering care provider. This study demonstrates that incidental findings on PET/CT scan are common and increase with age in patients with LVV. A significant number of patients required further investigation for incidental findings. Key Points • Incidental findings on PET/CT scan are common in our patient population with LVV. • Frequency of incidental findings in our patient population with LVV increased with age. • Findings from this study can be used by ordering providers to have an informed conversation with their patient about the frequency of incidental findings on PET/CT scans.