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

Highlights

• The authors present a review of 49 NS patients with emphasis on the occurrence of CVE, which are likely more frequent than previously thought.

• CVE in NS are significantly associated with PVE on imaging, occurring either along the lenticuostriate perforators or paraventricular veins.

• These patients tend to have a more aggressive clinical course when compared to NS patients without CVE.

• Patients with predominantly venous involvement may have distinct imaging findings on MRI and conventional angiogram studies.

Aim

To determine the occurrence of ischaemic and haemorrhagic events in patients with neurosarcoidosis at presentation and follow-up and to evaluate its association with perivascular enhancement.

Materials and methods

The MRI findings in patients with neurosarcoidosis who presented to our institute from 2002–2017 were retrospectively reviewed, with emphasis on cerebrovascular events. A chi-squared test was used to evaluate the statistical association with presence of perivascular enhancement.

Results

A total of 49 patients (32 females and 17 males) were analysed. Ischaemic events were noted in four patients at presentation while parenchymal haemorrhages occurred in three patients. The combined occurrence of cerebrovascular events (CVEs) at presentation was 14%. On follow-up, three additional patients developed ischaemic infarcts, of which, one patient had parenchymal haemorrhage at presentation. Additionally, one patient also developed new parenchymal haemorrhages. In total, 10 patients in current cohort developed CVEs, either at presentation or on follow-up. Perivascular enhancement was seen in 50% of patients with cerebrovascular events and 18% of patients with neurosarcoidosis, but no CVEs. This was statistically significant (p<0.05).

Conclusion

CVEs in patients with neurosarcoidosis are more common than previously reported and appear to be significantly related to the presence of perivascular enhancement on imaging.

Introduction

Sarcoidosis is an idiopathic inflammatory disorder with a reported global incidence between 10 and 20 per 100,000.¹ It is more common in Northern Europe, Japan, and central USA and along the east coast and is approximately four times more common in African-Americans.² Neurosarcoidosis (NS) is reported to occur in approximately 25% of patients with systemic sarcoidosis on autopsy studies, although the prevalence of imaging findings (15%) and clinical manifestations (5%) are less frequent. Even though non-specific, well-described imaging findings include meningitis, periventricular white matter (PVWM) signal changes, parenchymal granulomas, perivascular enhancement (PVE), cranial nerve or pachymeningeal involvement, and hydrocephalus.³ There is, however, a paucity of literature about the incidence of ischaemic or haemorrhagic strokes in NS.⁴ These are estimated to occur each in approximately 1% of cases by O'Dywer et al.⁵ This assessment, derived from a retrospective evaluation of multiple reported patient series, may be an underestimation of the actual incidence for multiple reasons.

Cerebrovascular events (CVE) in NS patients are significant for multiple reasons. These patients are often young and have few or minimal co-morbidities. In addition, these patients often pursue an aggressive clinical course.⁴ Another confounding factor is that the neurological manifestations may be the first or, sometimes, the only manifestation of NS, in which case, the diagnosis may be very challenging.⁶ It is, therefore, vital to be aware of their occurrence, significance, and expected imaging findings, as early diagnosis can potentially reduce the high morbidity in such cases.

The aim of the present study was to evaluate the occurrence of CVE in patients with NS and to assess if the presence of PVE correlates with such events.