Search Results (3)

A newly recognized fourth type of perivascular space has recently been described in the radiological literature. Despite its growing relevance, many radiologists are still unfamiliar with its imaging characteristics, often leading to misinterpretation as cystic neoplasms. Due to its potential for diagnostic confusion, further studies are necessary—particularly those incorporating high-quality imaging examples across various presentations—to facilitate accurate recognition and classification. Perivascular spaces (PVSs) of the brain are cystic, fluid-filled structures formed by the pia mater and located alongside cerebral blood vessels, particularly penetrating arterioles, venules, and capillaries. Under normal conditions, these spaces are small (typically <2 mm in diameter), but in rare instances, they may become markedly enlarged (>15 mm), exerting a mass effect on adjacent brain tissue. This newly identified fourth type of PVS is found in association with the M2 and M3 segments of the middle cerebral artery, typically within the anterior temporal lobe white matter. It may mimic low-grade cystic tumors on imaging due to its size and frequent presence of surrounding perifocal edema. We present two adult male patients with this rare PVS variant. The first patient, a 63-year-old, had a brain magnetic resonance imaging scan (MRI) that revealed a cystic lesion in the white matter of the right temporal lobe anterior pole, near the middle cerebral artery M2 segment, with perifocal vasogenic edema. The second patient, a 67-year-old, had a brain MRI that showed a cystic lesion in the white matter and subcortical region of the right temporal lobe anterior pole, with minimal surrounding gliosis or minimal edema. The cystic lesions in both patients remained unchanged over time on follow-up MRI. These cases illustrate the radiological complexity of this under-recognized entity and emphasize the importance of differential diagnosis to avoid unnecessary intervention. Full article

Neurovascular coupling is a key control mechanism in cerebral blood flow (CBF) regulation. Importantly, this process was demonstrated to be affected in several neurological disorders, including epilepsy. Neurovascular coupling (NVC) is the basis for functional brain imaging, such as PET, SPECT, fMRI, and fNIRS, to assess and map neuronal activity, thus understanding NVC is critical to properly interpret functional imaging signals. However, hemodynamics, as assessed by these functional imaging techniques, continue to be used as a surrogate to map seizure activity; studies of NVC and cerebral blood flow control during and following seizures are rare. Recent studies have provided conflicting results, with some studies showing focal increases in CBF at the onset of a seizure while others show decreases. In this brief review article, we provide an overview of the current knowledge state of neurovascular coupling and discuss seizure-related alterations in neurovascular coupling and CBF control. Full article

Brain arteriovenous malformation (bAVM) is a congenital defect affecting brain microvasculature, characterized by a direct shunt from arterioles to venules. Germline mutations in several genes related to transforming growth factor beta (TGF-β)/BMP signaling are linked to both sporadic and hereditary phenotypes. However, the low incidence of inherited cases makes the genetic bases of the disease unclear. To increase this knowledge, we performed a whole exome sequencing on five patients, on DNA purified by peripheral blood. Variants were filtered based on frequency and functional class. Those selected were validated by Sanger sequencing. Genes carrying selected variants were prioritized to relate these genes with those already known to be linked to bAVM development. Most of the prioritized genes showed a correlation with the TGF-βNotch signaling and vessel morphogenesis. However, two novel pathways related to cilia morphogenesis and ion homeostasis were enriched in mutated genes. These results suggest novel insights on sporadic bAVM onset and confirm its genetic heterogeneity. The high frequency of germline variants in genes related to TGF-β signaling allows us to hypothesize bAVM as a complex trait resulting from the co-existence of low-penetrance loci. Deeper knowledge on bAVM genetics can improve personalized diagnosis and can be helpful with genotype–phenotype correlations. Full article