Cerebrovascular manifestations in neurosarcoidosis: how common are they and does perivascular enhancement matter?

Uncommon and Miscellaneous Inflammatory Disorders of the Brain and Spine

Inflammatory disorders of the brain and spine have a highly variable MRI appearance, often demonstrating significant overlap in imaging features. The resulting diagnostic dilemma is particularly challenging when considering the more uncommon neuroinflammatory entities. Diligent examination of the salient clinical presentation and signal alteration on imaging examination is necessary when considering neuroinflammation as a diagnostic possibility and may aid in raising suspicion for a particular neuroinflammatory entity. This article reviews a selection of uncommon and miscellaneous inflammatory disorders of the brain and spine to raise awareness of the clinical and imaging features that may assist in this challenging diagnostic task.

Autoimmune encephalitis: what the radiologist needs to know

Autoimmune encephalitis is a relatively novel nosological entity characterized by an immune-mediated damage of the central nervous system. While originally described as a paraneoplastic inflammatory phenomenon affecting limbic structures, numerous instances of non-paraneoplastic pathogenesis, as well as extra-limbic involvement, have been characterized. Given the wide spectrum of insidious clinical presentations ranging from cognitive impairment to psychiatric symptoms or seizures, it is crucial to raise awareness about this disease category. In fact, an early diagnosis can be dramatically beneficial for the prognosis both to achieve an early therapeutic intervention and to detect a potential underlying malignancy. In this scenario, the radiologist can be the first to pose the hypothesis of autoimmune encephalitis and refer the patient to a comprehensive diagnostic work-up - including clinical, serological, and neurophysiological assessments.In this article, we illustrate the main radiological characteristics of autoimmune encephalitis and its subtypes, including the typical limbic presentation, the features of extra-limbic involvement, and also peculiar imaging findings. In addition, we review the most relevant alternative diagnoses that should be considered, ranging from other encephalitides to neoplasms, vascular conditions, and post-seizure alterations. Finally, we discuss the most appropriate imaging diagnostic work-up, also proposing a suggested MRI protocol.

Imaging of Vasculitis Associated with Systemic Disease

Vasculitides are characterized by inflammation of the vessel wall, with their categorization relying on clinical and paraclinical manifestations, vessel type, size, distribution, histological attributes, and associated conditions. This review delves into the salient neuroimaging hallmarks of central nervous system vasculitis associated with the most prevalent systemic diseases and highlightings potential pitfalls and diagnostic confounders.

Ischemic stroke in neurosarcoidosis: A retrospective cohort analysis

BACKGROUND

Cerebrovascular disease is rarely reported in neurosarcoidosis and constitutes one of its least well-described forms, though recognition for it has grown in the last decade with recent studies estimating a higher frequency of occurrence than previously known.

METHODS

Patients with ischemic stroke were included if the mechanism was directly attributable to sarcoidosis of the CNS. Patients were excluded if an alternative stroke etiology was of equal or higher likelihood than CNS sarcoidosis.

RESULTS

Neurologic disease was the initial presenting manifestation of sarcoidosis in 8/11 (72.7%), and ischemic stroke was an inaugural manifestation of sarcoidosis in 4/11 (36.4%). Small vessel disease was the predominant ischemia subtype (10/11, 90.9%) with pontine perforating vessels (6/11, 54.5%) and lenticulostriate arteries (3/11, 27.3%) being the vasculature most often affected. Vessels with a more rostral supratentorial distribution were uncommonly affected. Common neuroinflammatory accompaniments included leptomeningitis (10/11, 90.9%) and cranial nerve disease (3/11, 27.3%). Recurrent strokes occurred in 8/11 (72.7%), and recurrent neuroinflammation occurred in 7/11 (63.6%). Antiplatelet drugs were used in 6/11 (54.5%) patients. Most (10/11, 90.9%) required at least two lines of immunosuppression to achieve inflammatory disease remission in this context; infliximab was the most successfully employed immunosuppressant (7/8 treatment courses, 87.5%). Recurrent strokes occurred in 8/11 (72.7%) patients, and a second inflammatory attack occurred in 7/11 (63.6%) patients. The presenting median modified Rankin Scale score of 4.0 improved to 2.0 over a median period of follow-up of 52.0 months.

CONCLUSION

Ischemic strokes in neurosarcoidosis occur in a caudal-to-rostral distribution, tend to affect small caliber blood vessels that lack collateral blood flow, and typically associate with inflammatory leptomeningeal disease. The risk for relapse in the forms of stroke or neuroinflammation are high in this neurosarcoidosis phenotype.

[Sarcoidosis as prime example of a granulomatous disease]

Sarcoidosis is the most frequent immunologically related granulomatous disease and can serve as a model for understanding diseases within this category. The evidence on the diagnostics and treatment is so far limited. It is therefore all the more important that two new and significant guidelines on diagnosis and treatment of sarcoidosis were published during the last 2 years. Additionally, there were more new publications, which were considered for this review article. In this context, this review article provides a current update and overview of sarcoidosis. Pathophysiologically, there is an increasing understanding of the complex processes and interactions involved in the inflammatory processes and granuloma formation. The probability of a diagnosis of sarcoidosis is determined by compatible histology, the exclusion of differential diagnoses and if possible evidence of a multiorgan manifestation. The clinical course is variable and ranges from an asymptomatic manifestation to severe life-threatening organ failure. The most frequently affected organ are the lungs. Pulmonary fibrosis is the most severe form and is also decisive for mortality. An increasing focus is on the extrapulmonary organ manifestations, in particular, cardiac, hepatosplenic, gastrointestinal, renal, ocular and neurological involvement. Treatment, which consists primarily of immunosuppression, should be initiated in cases of organ-threatening or quality of life-impairing activity of the disease. Additional organ-specific management must also be evaluated. In cases of organ failure transplantation should be considered. Due to the limited evidence especially for the treatment of multiorgan sarcoidosis, when possible, patients with this disease should be included in clinical trials.

A Case of Neurosarcoid Presenting as Multiple Intraparenchymal Hemorrhages

This report explores the case of a 49-year-old African American male with a six-month history of multifocal neurological deficits who presented to an outside hospital after a generalized seizure. Patient was transferred to our tertiary medical center after brain imaging showed multiple bilateral supratentorial intraparenchymal hemorrhages (IPH). A brain biopsy confirmed parenchymal and perivascular non-caseating granulomas with vasculitis. The patient was definitively diagnosed with neurosarcoidosis (NS) and his condition improved with high dose corticosteroids and additional immunosuppressive therapies. Intracranial hemorrhage in the setting of NS is extremely rare, with fewer than thirty documented cases; however, this is likely an underestimation of its true prevalence. This case illustrates the difficulty in diagnosis as many other etiologies of IPH must be considered. Additionally, the clinical course and manifestations of NS is often quite variable. The uniqueness of this case lies in the rapid progression from seemingly incidental microhemorrhages to multiple large IPHs over two months. While the cause of this progression is not immediately apparent, a possible cause may be inadequate initial treatment due to delayed diagnosis. Our case demonstrates the importance of early recognition and initiation of immunosuppressive therapy, potentially leading to dramatic clinical improvement, as seen in this patient.

Vascular Involvement in Neurosarcoidosis: Early Experiences From Intracranial Vessel Wall Imaging

BACKGROUND AND OBJECTIVES

Cerebrovascular manifestations in neurosarcoidosis (NS) were previously considered rare but are being increasingly recognized. We report our preliminary experience in patients with NS who underwent high-resolution vessel wall imaging (VWI).

METHODS

A total of 13 consecutive patients with NS underwent VWI. Images were analyzed by 2 neuroradiologists in consensus. The assessment included segment-wise evaluation of larger- and medium-sized vessels (internal carotid artery, M1-M3 middle cerebral artery; A1-A3 anterior cerebral artery; V4 segments of vertebral arteries; basilar artery; and P1-P3 posterior cerebral artery), lenticulostriate perforator vessels, and medullary and deep cerebral veins. Cortical veins were not assessed due to flow-related artifacts. Brain biopsy findings were available in 6 cases and were also reviewed.

RESULTS

Mean patient age was 54.9 years (33-71 years) with an M:F of 8:5. Mean duration between initial diagnosis and VWI study was 18 months. Overall, 9/13 (69%) patients had vascular abnormalities. Circumferential large vessel enhancement was seen in 3/13 (23%) patients, whereas perforator vessel involvement was seen in 6/13 (46%) patients. Medullary and deep vein involvement was also seen in 6/13 patients. In addition, 7/13 (54%) patients had microhemorrhages in susceptibility-weighted imaging, and 4/13 (31%) had chronic infarcts. On biopsy, 5/6 cases showed perivascular granulomas with vessel wall involvement in all 5 cases.

DISCUSSION

Our preliminary findings suggest that involvement of intracranial vascular structures may be a common finding in patients with NS and should be routinely looked for. These findings appear concordant with previously reported autopsy literature and need to be validated on a larger scale.

Neuroimaging findings in rheumatologic disorders

Patients with rheumatological diseases may present with neurological manifestations of peripheral and/or central nervous system (CNS). Symptoms may be related to underlying rheumatological disease or CNS effects of immune-modulating drugs. Early diagnosis and therapy may help prevent serious complications. Magnetic resonance imaging (MRI), given its excellent soft tissue details, is the preferred imaging modality when evaluating patients with rheumatological disease and suspected CNS involvement. We present a review of the neuroimaging manifestations of various rheumatic diseases with emphasis on the imaging findings on MRI.

Pulmonary infarction caused by sarcoidosis vascular involvement: A case report

Sarcoidosis is a systemic granulomatous disease. In pulmonary sarcoidosis, granulomatous vascular involvement is a common feature that occurs in all types of vessels, including large elastic arteries to venules, but sarcoidosis complicated with pulmonary infarction has not been reported. We report a case of a 60 years old female, who was operated on a clinical diagnosis of lung cancer, and histological examination revealed a pulmonary infarction and sarcoidosis. In the pulmonary elastic arteries, granulomas infiltrated the adventitia and media, and caused elastic fiber collapse and destruction. Arterial occlusion by granulomas was observed in the edge of the infarcted area. It was considered that the arterial sarcoidosis granuloma involvement was the cause of pulmonary infarction. Sarcoidosis is a significant risk factor for cardiovascular events. However, pulmonary infarction is an extremely rare complication of sarcoidosis. Our case suggests that sarcoidosis may cause vascular events in the lungs.

CNS vasculopathies: Challenging mimickers of primary angiitis of the central nervous system

Primary angiitis of the central nervous system (CNS) is an inflammatory vasculopathy affecting the brain and spinal cord. It is a difficult diagnosis to make because of its insidious nonspecific course and its multiple mimics. This review identifies and discusses some noninfectious mimickers of primary CNS angiitis, including: reversible cerebral vasoconstriction syndrome, Sneddon's Syndrome, amyloid-beta-related angiopathy, Susac Syndrome, and neurosarcoidosis. Each condition will be reviewed in terms of epidemiology, pathology, clinical presentation, diagnostic approach, and treatment. Distinguishing these mimics from the primary angiitis of the CNS is important for proper treatment and prognosis.

Retrospective, dual-centre review of imaging findings in neurosarcoidosis at presentation: prevalence and imaging sub-types

AIM

To assess the prevalence of various imaging manifestations in neurosarcoidosis (NS) patients at presentation and to explore if specific imaging findings may cluster in different sub-groups.

MATERIALS AND METHODS

A retrospective, dual-institution, systematic imaging review was undertaken of the magnetic resonance imaging (MRI) findings in 100 consecutive NS patients who presented over a 15-year period. Clustering analysis (k-mode) was performed to evaluate co-occurrence of imaging findings.

RESULTS

Non-enhancing white matter (NEWM) lesions were the most common imaging abnormality (56%), followed by leptomeningeal (47%) and pachymeningeal (32%) involvement. Other common manifestations included cranial nerve involvement (30%), parenchymal granulomas (27%), hypothalamic-pituitary-adrenal axis involvement (26%), and hydrocephalus (14%). Additionally, a higher prevalence of perivascular enhancement (23%), cerebrovascular events (including ischaemic and haemorrhagic events; 17%), and ependymal involvement (20%) were noted than recognised previously. Additional k-mode analysis was performed to explore underlying disease sub-clusters. This was evaluated for clusters varying between two though five (k=2-5). For k=4, the analysis revealed that the imaging findings may possibly be divided into disease sub-sets of four groups, each with varying distribution of imaging manifestations and clinical manifestations.

CONCLUSION

Overall, NEWM lesions and meningeal involvement are the most common imaging manifestations of NS. The prevalence of perivascular enhancement, cerebrovascular events, and ependymal involvement is likely higher than reported previously. Additionally, different imaging findings in NS may cluster together and imaging subtypes in NS possibly exist.

Neurosarcoidosis: clinical manifestations, investigation and treatment

Sarcoidosis affects the nervous system in 10% of cases. When it does so it can affect any part of the nervous system and with all degrees of severity. It forms part of the differential diagnosis in inflammatory, infective, neoplastic and degenerative neurological diseases and may be very difficult to diagnose without histological confirmation. Recent clinical studies and the increasing availability of new biological treatments allow a much clearer understanding of the disease. This review summarises its clinical features, imaging and laboratory characteristics, treatment and outcome.

Brain miliary enhancement

PURPOSE

Miliary enhancement refers to the presence of multiple small, monomorphic, enhancing foci on T1-weighted post-contrast MRI images. In the absence of a clear clinical presentation, a broad differential diagnosis may result in invasive procedures and possibly brain biopsy for diagnostic purposes.

METHODS

An extensive review of the literature is provided for diseases that may present with miliary enhancement on T1-weighted brain MR images. Additional disease-specific findings, both clinical and radiological, are summarized and categorized by the presence or absence of perivascular space involvement.

RESULTS

Miliary pattern of enhancement may be due to a variety of underlying causes, including inflammatory, infectious, nutritional or neoplastic processes. The recognition of disease spread along the perivascular spaces in addition to the detection or exclusion of disease-specific features on MRI images, such as leptomeningeal enhancement, presence of haemorrhagic lesions, spinal cord involvement and specific localisation or systemic involvement, allows to narrow the potential differential diagnoses.

CONCLUSION

A systematic approach to disease-specific findings from both clinical and radiological perspectives might facilitate diagnostic work-up, and recognition of disease spread along the perivascular spaces may help narrowing down differential diagnoses and may help to minimize the use of invasive diagnostic procedures.

Neurosarcoidosis presenting with a partial Claude syndrome

Neurosarcoidosis when encountered by neurologists most commonly presents as cranial neuropathy, peripheral mononeuropathy,polyneuropathy, myopathy, meningitis or myelopathy. There are limited reports in the current literature on the cases of neurosarcoidosis patients presenting with ischaemic stroke. We discuss a 52-year-old patient with a known previous history of cutaneous sarcoidosis presenting with an acute third nerve palsy, facial weakness and ataxia. His magnetic resonance imaging (MRI) brain demonstrated focal signal changes in the midbrain consistent with an acute ischaemic event in the region of his third nucleus, suggesting a partial Claude syndrome presentation. Cerebrospinal fluid (CSF) examination demonstrated an elevated angiotensin-converting enzyme (ACE) level. We discuss the difficulties associated with confirming a diagnosis for his presentation and consider distinctions in stroke in neurosarcoid and its management in comparison to more common causes.

Neuroimaging Findings in Intracranial Sarcoid Phlebitis: A Case Report

INTRODUCTION

Venous phlebitis in Neurosarcoidosis (NS) is rare but is often associated with intracranial hemorrhage (ICH). Imaging findings in such cases have been recently described on susceptibility weighted imaging (SWI).

CASE PRESENTATION AND OUTCOME

We report a patient who presented with ICH. Magnetic resonance imaging provided evidence for parenchymal and leptomeningeal involvement while SWI and vessel wall imaging (VWI) helped confirmed NS associated intracranial phlebitis. The patient was subsequently diagnosed with systemic sarcoidosis.

DISCUSSION

The emerging role of VWI and SWI in the diagnosis of this rare entity is discussed.

Imaging findings in spinal sarcoidosis: a report of 18 cases and review of the current literature

PURPOSE

Spinal sarcoidosis, referring to involvement of the spine in sarcoidosis, is relatively rare and may mimic other neurological disease affecting the spine. The authors present a clinic radiological review of 18 spinal sarcoidosis patients who presented to a tertiary hospital, with emphasis on initial imaging and radiological response to treatment.

MATERIALS AND METHODS

We retrospectively reviewed our departmental imaging archives over a 15-year period and found 49 cases of neurosarcoidosis out of which 18 patients had spinal magnetic resonance imaging.

RESULTS

Approximately 72% (13/18) of the neurosarcoidosis patients showed some form of spinal involvement. The clinical, epidemiological and imaging data were reviewed for these 13 patients at presentation and follow-up. The findings on magnetic resonance imaging included leptomeningeal enhancement (61%), pachymeningeal (23%), intramedullary enhancing lesions (38%) and bony involvement (15%). The cervical segment was most frequently involved followed by the thoracic segment. Involvement was often long segment (4.2 spinal segments) with proclivity for the dorsal cord. Mean follow-up was 23.2 months. A complete or near-complete radiological response occurred in 66% while partial response was seen in 25% patients. Four patients had isolated central nervous system involvement including one with isolated spinal cord involvement. On diffusion-weighted imaging, the apparent diffusion coefficient of intramedullary lesions was increased compared to normal-appearing cord on baseline and subsequent follow-up scans.

CONCLUSIONS

Spinal sarcoidosis was previously considered uncommon but is being increasingly recognized with widespread use of magnetic resonance imaging. Proclivity for dorsal surface involvement is characteristic, although not necessarily pathognomonic. Also, quantitative diffusion studies may serve as a biomarker for the disease activity and parenchymal injury.