Late-onset temporal lobe epilepsy and dilatation of the hippocampal sulcus by an enlarged Virchow-Robin space

Risk factors for hippocampal cavities in a marginally housed population

Cavities in the hippocampus are morphological variants of uncertain significance. Aberrant neurodevelopment along with vascular and inflammatory etiologies have been proposed. We sought to characterize these cavities and their potential risk factors in a marginally housed population, with high rates of viral infection, addiction, and mental illness. (1) The volume of hippocampal cavities (HCavs) is greater in this highly multimorbid population compared to the general population. (2) Conventional vascular risk factors such as greater age and systolic blood pressure are associated with higher HCav volume. (3) Nonprescribed substance-related risk factors such as stimulant use or dependence, and smoking are associated with increased HCav volume independent of vascular risk factors. This is a retrospective analysis of an ongoing prospective study. We analyzed baseline data, including medical history, physical exam, psychiatric diagnosis, and MRI from a total of 375 participants. Hippocampal cavities were defined as spaces isointense to CSF on T1 MRI sequences, bounded on all sides by hippocampal tissue, with a volume of at least 1 mm³ . Risk factors were evaluated using negative binomial multiple regression. Stimulant use was reported by 87.3% of participants, with stimulant dependence diagnosed in 83.3% of participants. Prevalence of cavities was 71.6%, with a mean total bilateral HCav volume of 13.89 mm³ . On average, a 1 mmHg greater systolic blood pressure was associated with a 2.17% greater total HCav volume (95% CI = [0.57%, 3.79%], p = .0076), while each cigarette smoked per day trended toward a 2.69% greater total HCav volume (95% CI = [-0.87%, 5.54%], p = .058). A diagnosis of stimulant dependence was associated with a 95.6% greater total HCav volume (95% CI = [5.39%, 263.19%], p = .0335). Hypertension and diagnosis of stimulant dependence were associated with a greater total volume of HCav.

MRI-visible enlarged perivascular spaces: imaging marker to predict cognitive impairment in older chronic insomnia patients

OBJECTIVE

Perivascular spaces (PVS), components of the glymphatic system in the brain, have been known to be important conduits for clearing metabolic waste, and this process mainly increases during sleep. Sleep disruption might result in PVS dysfunction and cognitive impairment. In this study, we aim to explore whether MRI-visible enlarged perivascular spaces (EPVS) could be imaging markers to predict cognitive impairment in chronic insomnia patients.

METHOD

We obtained data from 156 patients with chronic insomnia and 79 age-matched healthy individuals. Using T2-weighted MRI images, visible EPVS in various brain regions were measured and analyzed. The associations between EPVS numbers and cerebrospinal fluid (CSF) β-amyloid 42 (Aβ42), total tau (t-tau), and phosphorylated tau (p-tau) level in chronic insomnia patients were evaluated.

RESULT

Our results showed that MRI-visible EPVS in the frontal cortex, centrum semiovale, basal ganglia, and hippocampus of chronic insomnia patients with impaired cognition (ICG) significantly increased than that in normal cognition (NCG) patients. The increased MRI-visible EPVS in the frontal cortex, centrum semiovale, and basal ganglia were also associated with the increased CSF Aβ42, t-tau, and p-tau level in ICG patients. MRI-visible EPVS in the basal ganglia and centrum semiovale had high sensitivity and specificity in distinguishing ICG chronic insomnia patients from those with NCG.

CONCLUSION

Our study indicated that MRI-visible EPVS in the basal ganglia and centrum semiovale might be valuable imaging markers to predict cognitive impairment in chronic insomnia patients. It will be meaningful to discern those cognitive decline patients in preclinical stage and take some measures to prevent disease progression.

KEY POINTS

• Increased MRI-visible EPVS were associated with the increased CSF Aβ42, t-tau, and p-tau level in older chronic insomnia patients with impaired cognition.

Enlarged hippocampal fissure in psychosis of epilepsy

Psychosis of epilepsy (POE) can be a devastating condition, and its neurobiological basis remains unclear. In a previous study, we identified reduced posterior hippocampal volumes in patients with POE. The hippocampus can be further subdivided into anatomically and functionally distinct subfields that, along with the hippocampal fissure, have been shown to be selectively affected in other psychotic disorders and are not captured by gross measures of hippocampal volume. Therefore, in this study, we compared the volume of selected hippocampal subfields and the hippocampal fissure in 31 patients with POE with 31 patients with epilepsy without psychosis. Cortical reconstruction, volumetric segmentation, and calculation of hippocampal subfields and the hippocampal fissure were performed using FreeSurfer. The group with POE had larger hippocampal fissures bilaterally compared with controls with epilepsy, which was significant on the right. There were no significant differences in the volumes of the hippocampal subfields between the two groups. Our findings suggest abnormal development of the hippocampus in POE. They support and expand the neurodevelopmental model of psychosis, which holds that early life stressors lead to abnormal neurodevelopmental processes, which underpin the onset of psychosis in later life. In line with this model, the findings of the present study suggest that enlarged hippocampal fissures may be a biomarker of abnormal neurodevelopment and risk for psychosis in patients with epilepsy.

MR Imaging of Hippocampal Sulcus Remnant: Age-Related Differences

The hippocampal sulcus remnant (HSR) is often observed at the medial temporal lobe on MR images. In the present study, we made a retrospective assessment of the frequency and age-related differences in HSR in routine brain MR examinations of 1000 patients, 494 females and 506 males. Cases with one or several spots that were hypointense on T1-weighted and FLAIR images and hyperintense on T2-weighted images were defined as positive for HSR. Abnormal spots with the same intensity as cerebrospinal fluid were observed in 210 out of 506 males and in 193 out of 494 females. No significant sex-related differences were observed in the frequency of HSR. The HSR was seen more frequently with age in both males and females. Patients with hypertension had a significantly higher frequency of HSR.

[Symptomatic giant Virchow-Robin spaces]

INTRODUCTION

Perivascular spaces, known as Virchow-Robin spaces (VRS), may become massively enlarged but are usually an incidental finding. However, a few reports on patients with unusually large VRS have mentioned association with neurological symptoms. We report a series of three symptomatic patients with extremely wide Virchow-Robin spaces documented on brain magnetic resonance imaging (MRI).

METHODS

We retrospectively analyzed the medical records and brain MRI of three symptomatic patients, who had been diagnosed with VRS widening.

CASE REPORTS

In all three patients, the unusual widening of the VRS was located within the subcortical white matter with asymmetric distribution. Their neurological symptoms were epilepsy and neurological deficits which correlated well with the lesions seen on the MRI. Two patients had associated white matter hyperintensities: in the first case associated gliosis and in the second case, with vascular leukoencephalopathy.

CONCLUSIONS

Enlarged symptomatic VRS are rare. The underlying pathophysiological mechanisms remain uncertain. We report three cases with symptomatic giant dilatation of the Virchow-Robin spaces.

Hippocampal sulcal cavities in depression and healthy individuals

BACKGROUND

A literature review suggested age and cognitive problems to be related to an increased prevalence of small areas of signal variation within the hippocampus observed on MRI, described as hippocampal sulcal cavities (HSCs; (Maller et al., 2011)). The current study aimed to describe the prevalence of HSCs in patients with treatment-resistant depression (TRD) and healthy controls over a large age-range.

METHODS

115 TRD patients and 86 controls underwent MRI brain scanning. Right and left HSCs were rated separately for prevalence and length.

RESULTS

HSCs were observed in 73.04% of those with TRD, statistically more prevalent (p=0.001) than amongst controls (51.16%). These findings are consistent with our review (66% prevalence in memory disorders and 47% in healthy controls). Furthermore, HSC presence and length was associated with aging.

LIMITATIONS

The study was cross-sectional so its implications for aging are tentative. A larger sample scanned longitudinally will allow for more sophisticated statistical methods by which to investigate the relationship between HSCs, aging, and TRD.

CONCLUSIONS

Although their clinical significance remains uncertain, the results of the current study suggest that HSCs are related with age and those with TRD have more aged brains than their peers.

Trigeminal neuralgia secondary to giant Virchow-Robin spaces: a case report with neuroimaging

Virchow-Robin spaces are pial-lined, interstitial, fluid-filled structures that accompany penetrating arteries and arterioles as they enter the cerebral substance. Occasionally they may enlarge and become giant Virchow-Robin spaces (GVRS) and produce mass effect. Various neurological symptoms have been described in association with GVRS, however, trigeminal neuralgia has not yet been reported in this context. We present a case of trigeminal neuralgia secondary to dorsal pontine giant Virchow-Robin spaces (GVRS) and highlight the diagnostic radiologic features. Routine 1.5 T MRI sequences were sufficient to diagnose the GVRS and a diffusion tensor imaging (DTI) study revealed distortion of the intrinsic trigeminal pathway. This study highlights the utility of routine MRI to study the intrinsic anatomy of the trigeminal pathway in pathological conditions.

Hippocampal sulcal cavities: prevalence, risk factors and relationship to memory impairment

While hippocampal volumes have been extensively examined in neuropsychiatric disorders and ageing, small areas of signal variation within the hippocampus commonly observed on MRI, described as hippocampal sulcal cavities (HSCs), have received less attention. We review the published literature on HSCs to examine their prevalence, putative aetiological factors such as hypertension, and possible cognitive correlates. HSCs were reported in 77% (66% weighted mean) of patients with memory disorders and 48% (47% weighted mean) of controls, and the prevalence increased with age in healthy subjects (r=0.64, p=0.047). A number of studies reported hypertension as a risk factor, and related their presence to poorer memory function. Further work is needed to fully understand the clinical significance of these lesions.

[Giant cystic widening of Virchow-Robin spaces, case report]

INTRODUCTION

Virchow-Robin spaces are very well-known anatomical and radiological entities. However, the observation of giant cystic widening of Virchow-Robin spaces is anecdotic. We report herein the case of a patient presenting with giant cystic widening of Virchow-Robin spaces located in both cerebral hemispheres.

OBSERVATION

A 26-year-old female presented with numbness of left arm and then, of both arms. CT scan showed many hypodensities located in the two hemispheres. Neurologic examination was normal. MR imaging allowed the diagnosis of giant cystic widening Virchow-Robin spaces in T2, T2*, T1 gadolinium and Flair weighted images. Neuropsychological investigations were normal.

CONCLUSION

Giant cystic widening of Virchow-Robin spaces are extremely rare entities. MR imaging helps the diagnosis. Only extreme dilatation of Virchow-Robin perivascular spaces close to ventricular system must be watched and treated in case of an obstructive hydrocephalus risk. When located in cerebral hemispheres, these dilatations are mostly asymptomatic and must not be confused with a cystic tumoral disease.

[Dilatation of Virchow-Robin perivascular spaces (types III cerebral lacunae): radio-clinical correlations]

BACKGROUND AND PURPOSE

Virchow-Robin spaces are pia-lined extensions of the subarachnoid space surrounding the path of brain vessels. When enlarged, such dilated perivascular spaces are often seen as foci of cerebrospinal fluid signal on MRI or CT scan. These foci are found in patients with miscellaneous clinical status. It is necessary to determine the radiological significance and clinical associations, if any, in such patients in order to give them the appropriate treatment.

METHODS

We describe the clinical and radiological findings of five patients and review the literature on perivascular Virchow-Robin spaces.

RESULTS

The mechanisms of dilated Virchow-Robin spaces are still not well understood. Such dilated perivascular spaces are found in two locations: typically in the high-convexity white matter of healthy elderly subjects, or surrounding the lenticulostriate vessels as they enter the basal ganglia. On MR images, they may be confused with lacunar infarcts. Most of the patients present with no symptoms: small dilatations located in the high convexity actually represent an anatomic variant, also called "état criblé". Sometimes, giant dilatations, or Poirier's type IIIb "expanding lacunae", found in the basal ganglia and midbrain may result in symptomatic hydrocephalus needing appropriate treatment. For other miscellaneous symptoms as headache, generalized epilepsy, dysmorphy, macrocephaly, there is no reliable correlation with enlarged perivascular spaces seen on MR images.

CONCLUSIONS

The real symptomatic dilated perivascular spaces need appropriate and quick treatment. Most of the other patients present with no symptoms and will remain asymptomatic.

Perivascular spaces: normal and giant

The purpose of this paper is to discuss both normal perivascular spaces (PVSs) and pathological giant perivascular spaces (GPVSs). The anatomy and physiology of normal PVSs, including important immunological and lymphatic roles, are described. Special attention is given to the Magnetic Resonance Imaging (MRI) findings of both normal and GPVSs. Furthermore, the clinical features and pathogenesis of GPVSs are explored, with special emphasis on the pathological implications of these lesions, and their relevance. It is important that symptomatic GPVSs not be mistaken for more devastating disease processes. When the lesions in question occur in a characteristic location along the path of a penetrating vessel, are isointense with cerebrospinal fluid on all MRI sequences, do not enhance with contrast material, are not calcified, and have normal adjacent brain parenchyma, their appearance is pathognomonic of GPVSs. The clinician should realize that an extensive differential diagnosis is superfluous and that biopsy is unnecessary in these patients. Instead, the clinical focus should be aimed at neurosurgical intervention, as dictated by the symptoms of mass effect.

Increased number of neural progenitors in human temporal lobe epilepsy

An increased neurogenesis is reported in animal models of mesial temporal lobe epilepsy (MTLE) but the fate of newborn cells is unknown. Here, we attempted to demonstrate neurogenesis in adult epileptic tissue obtained after hippocampectomy. MTLE hippocampi showed increased expression of division markers and of Musashi-1, a marker of neural progenitors, compared to control hippocampi. Large quantities of Musashi-1+ cells were obvious in the subgranular layer and the subventricular zone, both known neurogenic areas, and in the fissura hippocampi. Musashi-1 was expressed by small cells that were mainly vimentin+ or nestin+, rarely Dcx+ or PSA-NCAM+ and negative for markers of mature neurons or astrocytes. Some of them are present in the granular layer, the hilus, and CA1 area resembling the ectopic positions described in rodents. These findings demonstrate that neural progenitors proliferate in chronic epilepsy and suggest that the fissura hippocampi behaves like another neurogenic area.

Surgical considerations regarding giant dilations of the perivascular spaces

Object. Dilations of brain perivascular spaces (PVSs), also known as Virchow—Robin spaces, are routinely identified on magnetic resonance imaging studies of the brain and recognized as benign normal variants. Giant dilations occur only rarely and can be easily misdiagnosed as central nervous system tumors. The relevant surgical literature was reviewed to help establish indications for surgical intervention in these typically benign lesions.

Methods. Giant dilations of the PVSs in 12 patients who had undergone surgery for several different indications were identified. Both clinical and radiographic presentations of these patients were reviewed along with the surgical procedures.

Conclusions. Dilations of the PVSs can become giant lesions that may necessitate surgical intervention to relieve mass effect or hydrocephalus. The relationship of these lesions to neurological symptoms such as tremor and seizures remains unclear.

Developmental abnormalities of the hippocampus in first-episode schizophrenia

BACKGROUND

The human hippocampus becomes visible during the first trimester and folds to form the hippocampal fissure (HF) in the second trimester. The walls of this fissure fuse by 30 weeks, although small residual cavities can occur if development is disrupted. The primary purpose of this study was to determine if hippocampal fissures are evident in schizophrenia. A second goal was to assess the association between HF size and premorbid and clinical features of the illness.

METHODS

Magnetic resonance imaging scans were obtained on 33 patients with first-episode schizophrenia and 19 healthy volunteers. Hippocampal fissures were measured using semi-automated procedures, and hippocampi were manually traced. Birth history and premorbid functioning were assessed using maternal report.

RESULTS

Patients had a significantly larger mean HF volume and a nonsignificantly smaller hippocampal volume. Hippocampal fissure size was significantly associated with poor educational achievement and with anxiety-depression symptoms during the onset of illness. Smaller hippocampal size was associated with poor premorbid adjustment.

CONCLUSIONS

Larger HF size and an association between low educational achievement and enlarged HFs suggest abnormal neurodevelopment in schizophrenia. The association between HF size and anxiety-depression symptoms suggests that hippocampal abnormalities underlying HF dilatation may be a predisposing factor for increased stress sensitivity.

Dilatação dos espaços de Virchow-Robin em pacientes com migrânea

Os espaços de Virchow-Robin (EVR) são invaginações do espaço subpial, formando uma bainha de revestimento tubular contendo um vaso, que separa o espaço subaracnóide do subpial. A ressonância magnética (RM) é o único método de imagem capaz de avaliar este detalhe anatômico. Nós estudamos a possível associação entre EVR dilatados e migrânea. Avaliamos 70 pacientes com idade compreendida entre 13 e 54 anos (média 36,5 anos), com diagnóstico clínico de migrânea e comparamos com grupo controle com igual número de pacientes com idade compreendida entre 14 e 64 anos (média de 42 anos), sem antecedentes de cefaléia. Observamos aumento dos EVR em 28 casos (40%) dos pacientes com migrânea. No grupo controle tal achado foi encontrado em apenas 5 casos (7,1%). Alertamos, ainda, sobre a importância na detecção e reconhecimento dos EVR, bem como o seu diagnóstico diferencial com infartos lacunares e cistos da fissura coroidea.

Hippocampal sulcal cavities on MRI: relationship to age and apolipoprotein E genotype

Hippocampal sulcal cavities are usually considered incidental findings on brain MRI. In a group of 92 elderly volunteers, the authors graded the number and size of hippocampal sulcal cavities with brain MRI to obtain a cavity score. Cavity scores increased with age, and were higher in subjects carrying the APOE epsilon4 or epsilon2 alleles than in subjects with the epsilon3/3 genotype. Age-related morphologic changes in the hippocampus may be mediated by the APOE genotype.