Tumefactive Virchow-Robin spaces

Giant tumefactive mesencephalothalamic Virchow-Robin space with triventricular hydrocephalus: a case-based systematic literature review

BACKGROUND

The perivascular spaces of the brain are also known as Virchow-Robin spaces (VRSs). Dilated Virchow-Robin spaces in the brainstem are rare and mainly cause symptoms due to obstructive hydrocephalus, less frequently because of their size, mass effect, and impact on eloquent structures.

CASE ILLUSTRATION

We present a patient with giant tumefactive VRS with hydrocephalus and neurological symptoms who was treated with endoscopic third ventriculostomy (ETV) followed by microscopic cyst fenestration. On the basis of this observation, we performed a thorough review of the literature to evaluate different treatment options.

RESULTS

An 11-year-old girl presented with a headache for 3 months. The patient had a giant tumefactive mesencephalothalamic VRS with triventricular hydrocephalus. She was initially treated with endoscopic third ventriculostomy and multiple cyst fenestration. Symptomatic cyst regrowth required multiple cyst fenestrations via transcallosal transchoroidal (N = 2) and subtemporal approaches (N = 1) at the 2- and 4-year follow-ups. A literature review of these conditions allowed the detection of 12 cases (including our index case), and only 25% (3/12) of the patients underwent cyst fenestration 16.7% (2/12) required endoscopic fenestration and 8.3% (1/12) required microscopic fenestration.

CONCLUSION

Giant mesencephalothalamic dVRSs are rare in the pediatric population. These patients are usually symptomatic due to obstructive hydrocephalus. Surgical options are endoscopic third ventriculostomy, ventricular shunt procedures, or direct cyst fenestration (microscopic or endoscopic). Close follow-up is mandatory owing to the risk of progression of the disease. Cyst fenestration resolves symptoms immediately, as it addresses both hydrocephalus and mass effects due to the cystic lesion in the same setting.

Radiology-pathology correlation: Giant tumefactive perivascular spaces

Dilated perivascular spaces (PVSs) are common and easily recognized on imaging. However, rarer giant tumefactive PVSs (GTPVSs) can have unusual multilocular cystic configurations, and are often confused for other pathologic entities, including neoplasms, cystic infarctions, and neuroepithelial cysts. Because GTPVSs are scarcely encountered and even more infrequently operated upon, many radiologists are unaware of the imaging and pathologic features of these lesions. Here, a case of a resected GTPVS is presented, highlighting both its radiologic and histologic characteristics, and discussing how such lesions can be differentiated from their closest mimickers on imaging.

Overview of the Current Knowledge and Conventional MRI Characteristics of Peri- and Para-Vascular Spaces

Brain spaces around (perivascular spaces) and alongside (paravascular or Virchow-Robin spaces) vessels have gained significant attention in recent years due to the advancements of in vivo imaging tools and to their crucial role in maintaining brain health, contributing to the anatomic foundation of the glymphatic system. In fact, it is widely accepted that peri- and para-vascular spaces function as waste clearance pathways for the brain for materials such as ß-amyloid by allowing exchange between cerebrospinal fluid and interstitial fluid. Visible brain spaces on magnetic resonance imaging are often a normal finding, but they have also been associated with a wide range of neurological and systemic conditions, suggesting their potential as early indicators of intracranial pressure and neurofluid imbalance. Nonetheless, several aspects of these spaces are still controversial. This article offers an overview of the current knowledge and magnetic resonance imaging characteristics of peri- and para-vascular spaces, which can help in daily clinical practice image description and interpretation. This paper is organized into different sections, including the microscopic anatomy of peri- and para-vascular spaces, their associations with pathological and physiological events, and their differential diagnosis.

Extensive widening of Virchow-Robin spaces in the frontal lobe: two case reports and systematic review of the literature

AIM

To report our experience on giant tumefactive Virchow-Robin spaces (GTVRS) in the frontal lobe and perform a systematic review of previous reports on GTVRS.

MATERIALS AND METHODS

This is a retrospective single-center study reporting the clinical manifestations, magnetic resonance (MR) imaging appearance, differential diagnosis, and management of two patients diagnosed with frontal lobe GTVRS at Bahcesehir University School of Medicine Goztepe Hospital in the past 5 years. A systematic literature search was performed in the PubMed and Google Scholar databases, with case selection criteria including Virchow-Robin spaces (VRS) size greater than 1.5 cm, frontal lobe localization, and the presence of MR imaging. The search strategy included only English language keywords. The systematic review was searched between database inception and May 6, 2022.

RESULTS

A total of 18 cases were included in the study. Of the 15 cases with known sex, nine were female and six male. The median age was 29.8 with an age range of 4-57. Eleven of the 18 lesions were in the right frontal lobe. The lesions were multilocular in 15 cases and unilocular in three cases. All lesions had signal intensity as cerebrospinal fluid, showed no perifocal edema, and did not enhance. A hyperintensity was noted around the 14 lesions on the FLAIR sequence. Ten lesions showed cortical thinning adjacent to the lesion. No abnormality was detected on DWI, SWI, and MRS. Follow-up imaging was available in ten patients without any interval change. Unnecessary surgical interventions were noted in three cases.

CONCLUSIONS

The results of reported cases and the literature review emphasize the role of MR imaging in the diagnosis of frontal lobe GTVRS. Beyond diagnostic consideration, GTVRS may have prognostic value and often indicate a "don't touch lesion" albeit requiring further consideration on a case-to-case basis. Familiarity with this entity improves diagnostic accuracy and, prevents accidental diagnosis of any neoplasm or other diseases.

Giant Tumefactive Perivascular Spaces: An Unusual Cause of Holmes Tremor

A 34-year-old man presented with a 2-year history of medically refractory Holmes tremor in the right upper limb. Magnetic resonance imaging revealed a large, nonenhancing, multiseptate cystic lesion of cerebrospinal fluid intensity in the left thalamopeduncular region causing brainstem compression and hydrocephalus. A diagnosis of giant tumefactive perivascular spaces was made after a biopsy ruled out an infectious or neoplastic etiology. Significant clinicoradiologic improvement was noted following a ventriculoperitoneal shunt. Giant tumefactive perivascular spaces should be included as one of the rare differentials of a large, nonenhancing cystic lesion situated along the course of perforator vessels. Treatment options include cerebrospinal fluid diversion with or without cyst fenestration.

Giant Tumefactive Perivascular Space: Advanced Fusion MR Imaging and Tractography Study-A Case Report and a Systematic Review

Perivascular spaces (PVSs) are small extensions of the subpial cerebrospinal space, pial-lined and interstitial fluid-filled. They surround small penetrating arteries, and veins, crossing the subarachnoid space to the brain tissue. Magnetic Resonance Imaging (MRI) shows a PVS as a round-shape or linear structure, isointense to the cerebrospinal fluid, and, if larger than 1.5 cm, they are known as giant/tumefactive PVSs (GTPVS) that may compress neighboring parenchymal/liquoral compartment. We report a rare asymptomatic case of GTPVS type 1 in a diabetic middle-aged patient, occasionally discovered. Our MRI study focuses on diffusion/tractography and fusion imaging: three-dimensional (3D) constructive interference in steady state (CISS) and time of fly (TOF) sequences. The advanced and fusion MR techniques help us to track brain fiber to assess brain tissue compression consequences and some PVS anatomic features as the perforating arteries inside them.

The etiology and evolution of magnetic resonance imaging-visible perivascular spaces: Systematic review and meta-analysis

Objectives

Perivascular spaces have been involved in neuroinflammatory and neurodegenerative diseases. Upon a certain size, these spaces can become visible on magnetic resonance imaging (MRI), referred to as enlarged perivascular spaces (EPVS) or MRI-visible perivascular spaces (MVPVS). However, the lack of systematic evidence on etiology and temporal dynamics of MVPVS hampers their diagnostic utility as MRI biomarker. Thus, the goal of this systematic review was to summarize potential etiologies and evolution of MVPVS.

Methods

In a comprehensive literature search, out of 1,488 unique publications, 140 records assessing etiopathogenesis and dynamics of MVPVS were eligible for a qualitative summary. 6 records were included in a meta-analysis to assess the association between MVPVS and brain atrophy.

Results

Four overarching and partly overlapping etiologies of MVPVS have been proposed: (1) Impairment of interstitial fluid circulation, (2) Spiral elongation of arteries, (3) Brain atrophy and/or perivascular myelin loss, and (4) Immune cell accumulation in the perivascular space. The meta-analysis in patients with neuroinflammatory diseases did not support an association between MVPVS and brain volume measures [R: −0.15 (95%-CI −0.40–0.11)]. Based on few and mostly small studies in tumefactive MVPVS and in vascular and neuroinflammatory diseases, temporal evolution of MVPVS is slow.

Conclusion

Collectively, this study provides high-grade evidence for MVPVS etiopathogenesis and temporal dynamics. Although several potential etiologies for MVPVS emergence have been proposed, they are only partially supported by data. Advanced MRI methods should be employed to further dissect etiopathogenesis and evolution of MVPVS. This can benefit their implementation as an imaging biomarker.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=346564, identifier CRD42022346564.

Spontaneous regression of asymptomatic tumefactive perivascular spaces in the anterior temporal lobe

Perivascular spaces are fluid-filled spaces that surround the perforating vessels of the brain and are normal findings on brain imaging. These are usually asymptomatic and are considered a manifestation of aging. Perivascular spaces occasionally undergo significant enlargement and are referred to as tumefactive perivascular spaces, which are often indistinguishable from neoplastic lesions. Spontaneous regression of tumefactive perivascular spaces during follow-up is rare. We report the imaging findings and clinical course of a patient who showed spontaneous regression of tumefactive perivascular spaces in the anterior temporal lobe, together with a literature review and discussion regarding the characteristics and pathogenesis of spontaneous regression of tumefactive perivascular spaces. Most studies in the available literature report tumefactive perivascular spaces in the anterior temporal lobe; in our view, the characteristics of anterior temporal lobe tumefactive perivascular spaces may differ from those of tumefactive perivascular spaces that occur at other locations.

Perivascular Spaces, Glymphatic System and MR

The importance of the perivascular space (PVS) as one of the imaging markers of cerebral small vessel disease (CSVD) has been widely appreciated by the neuroradiologists. The PVS surrounds the small blood vessels in the brain and has a signal consistent with the cerebrospinal fluid (CSF) on MR. In a variety of physio-pathological statuses, the PVS may expand. The discovery of the cerebral glymphatic system has provided a revolutionary perspective to elucidate its pathophysiological mechanisms. Research on the function and pathogenesis of this system has become a prevalent topic among neuroradiologists. It is now believed that this system carries out the similar functions as the lymphatic system in other parts of the body and plays an important role in the removal of metabolic waste and the maintenance of homeostatic fluid circulation in the brain. In this article, we will briefly describe the composition of the cerebral glymphatic system, the influencing factors, the MR manifestations of the PVS and the related imaging technological advances. The aim of this research is to provide a reference for future clinical studies of the PVS and glymphatic system.

Physiology and Clinical Relevance of Enlarged Perivascular Spaces in the Aging Brain

Perivascular spaces (PVS) are fluid-filled compartments that are part of the cerebral blood vessel wall and represent the conduit for fluid transport in and out of the brain. PVS are considered pathologic when sufficiently enlarged to be visible on MRI. Recent studies have demonstrated that enlarged PVS (ePVS) may have clinical consequences related to cognition. Emerging literature points to arterial stiffening and abnormal protein aggregation in vessel walls as 2 possible mechanisms that drive ePVS formation. We describe the clinical consequences, anatomy, fluid dynamics, physiology, risk factors, and in vivo quantification methods of ePVS. Given competing views of PVS physiology, we detail the 2 most prominent theoretical views and review ePVS associations with other common small vessel disease markers. Because ePVS are a marker of small vessel disease and ePVS burden is higher in Alzheimer disease, a comprehensive understanding about ePVS is essential in developing prevention and treatment strategies.

Contribution of advanced MRI to the diagnosis of giant tumefactive perivascular spaces

BACKGROUND

Giant tumefactive perivascular spaces (PVSs) are uncommon benign cystic lesions. They can imitate cystic neoplasms.

PURPOSE

To evaluate the contribution of advanced neuro magnetic resonance imaging (MRI) techniques in the diagnosis of giant tumefactive PVSs and to further characterize these unusual cerebral lesions.

MATERIAL AND METHODS

The MRI scans of patients with tumefactive PVS diagnosed between 2010 and 2019 were retrospectively reviewed. All imaging studies included three plane conventional cerebral MRI sequences as well as precontrast 3D T1 MPRAGE, post-gadolinium 3D T1 acquisitions, sagittal plane 3D T2 SPACE, diffusion-weighted imaging, and time-of-flight (TOF) angiography. Some patients received perfusion MR, MR spectroscopy, diffusion tensor imaging (DTI), and contrast-enhanced TOF MR angiography.

RESULTS

A perforating vessel was demonstrated in 16 patients (66.7%) by TOF imaging. In four patients, there were intracystic vascular collaterals on contrast-enhanced TOF MR angiography. Septal blooming was observed in four patients in susceptibility-weighted imaging. On perfusion MR, central hyperperfusion was observed in four patients, and peripheral hyperperfusion was observed in one patient. On MR spectroscopy, choline increase was observed in two patients, and there was a lactate peak in three patients, and both a choline increase and lactate peak in one patient. On DTI, there was fiber distortion in five patients and fiber deformation in one patient.

CONCLUSION

Advanced MRI techniques and 3D volumetric high-resolution MRI sequences can provide a valuable contribution to the diagnosis and can be successfully used in the management of these lesions.

Cognitive impairment due to widespread enlarged perivascular spaces

Perivascular spaces, also known as Virchow-Robin spaces, are usually considered as a normal, asymptomatic finding. However, this finding can occasionally demonstrate an atypical appearance and can be symptomatic. We report herein a rare case of cognitive impairment associated with extremely enlarged perivascular spaces. A 68-year-old Japanese woman visited our hospital with a 1-year history of progressive memory impairment. In addition to temporal disorientation and short-term memory impairment, neuropsychological testing showed frontal lobe-related symptoms such as slowed thinking processes, reduced verbal fluency, attention deficit, and reduced working memory. Magnetic resonance imaging of the brain showed widespread enlarged perivascular spaces almost symmetrically in the subcortical white matter of bilateral hemispheres, prominently in bilateral insulas, and frontal opercula. On 99mTc-ethyl cysteinate dimer single photon emission computed tomography, hypoperfusion was apparent in bilateral insulas and frontal opercula where enlarged periventricular spaces were prominent, whereas cerebral perfusion was preserved in areas where enlargement of perivascular spaces was mild or absent. Because symptoms were consistent with the distribution of the enlarged perivascular spaces and hypoperfusion in the brain, cognitive impairment due to enlarged perivascular spaces was diagnosed. Clinicians should note enlarged perivascular spaces as a potential cause of neurological deficits including cognitive impairment.

Imaging of vascular cognitive impairment

Vascular cognitive impairment (VCI) is a major health challenge and represents the second most common cause of dementia. We review the updated imaging classification and imaging findings of different subtypes of VCI. We will focus on the magnetic resonance imaging (MRI) markers of each subtype and highlight the role of advanced MR imaging sequences in the evaluation of these patients. Small vessel dementia appears as white matter hyperintensity, lacunae, microinfarcts, and microbleeds. Large vessel dementia includes strategic infarction and multi-infarction dementias. Hypoperfusion dementia can be seen as watershed infarcts and cortical laminar necrosis. Hemorrhagic dementia results from cerebral amyloid angiopathy and cortical superficial siderosis. Hereditary forms of VCI, caused by gene mutations such as CADASIL, should be suspected when dementia presents in young patients. Mixed dementia is seen in patients with Alzheimer's disease and the coexistence of cerebrovascular disease.

Opercular perivascular cysts: A proposed new subtype of dilated perivascular spaces

PURPOSE

Dilated perivascular spaces are a common finding on brain MRI, traditionally classified into three types based on location and relationship to vessels. Recent studies have characterised an additional variant of dilated perivascular spaces that arise within the anterior temporal lobe and have unique neuroimaging features. These particular perivascular spaces are associated with a vascular loop of a branch of the middle cerebral artery (MCA) and commonly demonstrate perilesional T2/FLAIR signal. To our knowledge, these have not previously been described in the frontal lobe.

METHOD

Dilated perivascular spaces associated with a vascular loop of a branch of the middle cerebral artery (MCA) identified at our institution were reviewed for imaging characteristics and anatomical location.

RESULTS

18 cases were identified. 16 were located in the anterior temporal lobe and two were located in the frontal operculum. All demonstrated internal signal characteristics identical to CSF on all sequences, with no contrast enhancement or susceptibility artefact and variable perilesional T2/FLAIR signal.

CONCLUSIONS

We report further evidence of a distinct subtype of dilated perivascular spaces occurring in the anterior temporal lobe in association with a vascular loop of a branch of the MCA. In addition, we have demonstrated that these may also occur in the frontal operculum. We therefore suggest that these dilated perivascular spaces of the operculum be recognised as a separate, fourth, subtype of perivascular space and propose the term "opercular perivascular cyst".

Tumefactive perivascular space demonstrated with post-contrast time-of-flight MR angiography

The cerebral perivascular spaces are interstitial fluid-filled anatomic structures surrounding the perforating arteries. They appear as small, round or curvilinear structures on magnetic resonance (MR) imaging. Occasionally, these structures may become very large and cause mass effect. In this case, they may imitate malignant processes and are referred to as tumefactive perivascular spaces. In this study, we present a case of tumefactive perivascular space demonstrated with post-contrast time-of-flight (TOF) MR angiography. To our knowledge, there have been no previous clear demonstrations of the perforating artery in tumefactive perivascular space with contrast-enhanced TOF MR angiography. The purpose of this study was to describe advanced imaging findings in this unusual condition.