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Arachnoid granulations

Satoshi Tsutsumi, Hideo Ono, Yukimasa Yasumoto
PURPOSE: Arachnoid granulations (AGs) occasionally appear to protrude into the calvarial convexity, lying close to the bridging veins (BVs). This study aims to characterize such AGs and BVs using magnetic resonance imaging (MRI). METHODS: Ninety-five patients were enrolled in this study. Initially, stepwise frontal craniotomy was performed in an injected cadaver head. Next, examinations with contrast MRI were performed involving the whole cranial vault. RESULTS: In cadaveric dissection, the AGs located in the parasagittal regions appeared as outward protrusions through the dura mater and in contact with the diploic veins...
September 19, 2016: Surgical and Radiologic Anatomy: SRA
Nicholas L Deep, Joseph M Hoxworth, Christopher J Stevens, Michael J Link, Colin L W Driscoll, Christopher P Wood
OBJECTIVE: The radiologic appearance of arachnoid granulations (AGs) in typical locations is well established and they are rarely mistaken for other pathologies. However, when large and seen in atypical locations, such as along the posterior petrous bone, AGs can be a source of diagnostic and therapeutic confusion. We present two cases of giant posterior temporal bone AGs and review their clinical presentation, potential complications, and an imaging-based differential diagnosis. PATIENTS: Two patients with surgically or pathologically proven giant symptomatic AGs in the posterior petrous bone...
August 2016: Otology & Neurotology
Greta B Liebo, John Jack I Lane, Jamie J Van Gompel, Laurence J Eckel, Kara M Schwartz, Vance T Lehman
BACKGROUND/PURPOSE: Brain herniation into presumed arachnoid granulations (BHAG) is an increasingly recognized entity. Though it has previously been described as isointense to brain matter on magnetic resonance imaging (MRI), we have encountered 21 cases in our clinical practice, many of which have signal abnormality in the herniated or adjacent parenchyma. We performed a systematic analysis on these cases to further understand the clinical significance. METHODS: This is a retrospective analysis of cases collected from our clinical MRI practice...
June 8, 2016: Journal of Neuroimaging: Official Journal of the American Society of Neuroimaging
William G Bradley
Normal pressure hydrocephalus (NPH) is a syndrome found in the elderly, which is characterized by ventriculomegaly and deep white matter ischemia (DWMI) on magnetic resonance imaging (MRI) and the clinical triad of gait disturbance, dementia, and urinary incontinence. NPH has been estimated to account for up to 10% of cases of dementia and is significant because it is treatable by ventriculoperitoneal shunting. Patients with a known cause of chronic communicating hydrocephalus, that is, meningitis or hemorrhage, tend to respond better than patients with the so-called "idiopathic" form, most likely because of poor selection criteria in the past...
April 2016: Seminars in Ultrasound, CT, and MR
Recep Sade, Hayri Ogul
No abstract text is available yet for this article.
April 2016: Headache
R Shane Tubbs, Amin Demerdash, Anthony V D'Antoni, Marios Loukas, Charles Kulwin, Rod J Oskouian, Aaron Cohen-Gadol
BACKGROUND: The middle meningeal artery (MMA) is often sacrificed during neurosurgical procedures in the region of the pterion. This maneuver, herein, is hypothesized to be a potential reason for the development of postoperative hydrocephalus by injuring the vascular supply to the arachnoid granulations near the vertex of the skull, and thus disrupting their ability to allow for transfer of CSF from the subarachnoid space to the venous system. MATERIALS AND METHODS: To test this theory, the middle meningeal artery was isolated at the skull base and injected with India ink...
March 14, 2016: Child's Nervous System: ChNS: Official Journal of the International Society for Pediatric Neurosurgery
Sonaz Malekzadehlashkariani, Isabel Wanke, Daniel A Rüfenacht, Diego San Millán
INTRODUCTION: Brain herniations (BH) into arachnoid granulations (AG) in dural venous sinuses and calvarium have rarely been reported in the literature. METHODS: MRIs of 38 patients with BH into AG (BHAG) were retrospectively analyzed. Locations of BHAG, gyrus/lobe of the herniated brain, parenchymal abnormalities of the BH, and clinical and radiological conditions with raised intracranial pressure were recorded. RESULTS: Sixty-eight BHAG were found, by order of frequency, in the occipital squama (OS), transverse sinus (TS), lateral lacuna of the superior sagittal sinus (LLSSS), and straight sinus (SS), with cerebellar tissue being the most frequently involved in BHAG (94...
May 2016: Neuroradiology
Baomin Li, Yongping Liang, Xiangyu Cao, Jun Wang, Xinfeng Liu, Chunshui Yang, Chunming Wang
OBJECTIVE: To explore the imaging anatomic features of symptomatic cerebral venous sinus stenosis, and evaluate the efficacy and feasibility of different treatment methods. METHODS: From August 2001 to September 2004, 173 patients (transverse sinus stenosis 150, middle of the superior sagittal sinus stenosis 18, proximal part of sigmoid sinus stenosis 3, straight sinus stenosis 2; combined with sinus diverticulum 14, combined with Labbe's vein stenosis 3) were confirmed venous sinus stenosis by digital subtraction angiography (DSA)...
November 17, 2015: Zhonghua Yi Xue za Zhi [Chinese medical journal]
Christopher R Durst, David A Ornan, Michael A Reardon, Prachi Mehndiratta, Sugoto Mukherjee, Robert M Starke, Max Wintermark, Avery Evans, Mary E Jensen, R Webster Crowley, John Gaughen, Kenneth C Liu
BACKGROUND AND PURPOSE: While recent literature has described the prevalence of transverse sinus stenosis in patients with idiopathic intracranial hypertension, tinnitus, and refractory headaches, it is unclear what the prevalence is in the general population. This study evaluates the prevalence of venous sinus stenosis and hypoplasia in the general patient population. MATERIALS AND METHODS: 355 of 600 consecutive patients who underwent CT angiography of the head met the inclusion criteria...
November 2016: Journal of Neurointerventional Surgery
Bilal Battal, Salih Hamcan, Veysel Akgun, Sebahattin Sari, Oguzhan Oz, Mustafa Tasar, Mauricio Castillo
OBJECTIVES: To determine frequency, imaging features and clinical significance of herniations of brain parenchyma into dural venous sinuses (DVS) and/or calvarium found on MRI. METHODS: A total of 6160 brain MRI examinations containing at least one high-resolution T1- or T2-weighted sequence were retrospectively evaluated to determine the presence of incidental brain herniations into the DVS or calvarium. MRI sequences available for review were evaluated according to their capability to demonstrate these herniations...
June 2016: European Radiology
Masakazu Miyajima, Hajime Arai
The traditional hypothesis of cerebrospinal fluid (CSF) hydrodynamics presumes that CSF is primarily produced in the choroid plexus (CP), then flows from the ventricles into the subarachnoid spaces, and mainly reabsorbed in the arachnoid granulations. This hypothesis is necessary to reconsider in view of recent research and clinical observations. This literature review presents numerous evidence for a new hypothesis of CSF hydrodynamics-(1) A significantly strong relationship exists between the CSF and interstitial fluid (IF), (2) CSF and IF are mainly produced and absorbed in the parenchymal capillaries of the brain and spinal cord...
2015: Neurologia Medico-chirurgica
Aaron K Remenschneider, Elliott D Kozin, Hugh Curtin, Felipe Santos
OBJECTIVES/HYPOTHESIS: The objective of this study was to utilize techniques of otopathology to gain insight into the pathogenesis, sites of origin, and associated findings in idiopathic lateral skull base defects. STUDY DESIGN: Histopathologic analysis of temporal bones from an otopathology repository. METHODS: Specimens from a human temporal bone repository were investigated for clinical or otopathologic evidence of occult bony dehiscence indicating communication between the subarachnoid space and air cells of the temporal bone...
August 2015: Laryngoscope
Helen N Schwerdt, Usamma Amjad, Jennie Appel, Ali M Elhadi, Ting Lei, Mark C Preul, Ruth E Bristol, Junseok Chae
Reliable cerebrospinal fluid (CSF) draining methods are needed to treat hydrocephalus, a chronic debilitating brain disorder. Current shunt implant treatments are characterized by high failure rates that are to some extent attributed to their length and multiple components. The designed valve, made of hydrogel, steers away from such protracted schemes and intends to provide a direct substitute for faulty arachnoid granulations, the brain's natural CSF draining valves, and restore CSF draining operations within the cranium...
March 2015: Annals of Biomedical Engineering
Long Chen, Gavin Elias, Marina P Yostos, Bojan Stimec, Jean Fasel, Kieran Murphy
INTRODUCTION: Cerebrospinal fluid (CSF) absorption has long been held to predominantly entail drainage into the venous outflow system via the intracranial arachnoid granulations. Newer data suggest pathways involving spinal arachnoid granulations and lymphatic channels may also make substantial contributions to CSF outflow. METHODS: The putative major CSF outflow pathways and their proportionate contribution to CSF absorption were reviewed in this article. RESULTS: CSF is absorbed and drained in bulk not just through cerebral arachnoid granulations (CAG) but also through spinal arachnoid granulations (SAG) and a lymphatic pathway involving egress through cranial and spinal nerve sheaths...
February 2015: Neuroradiology
Peter H Gaudet, Richard J Cawthorn, Melanie A Buote, J Frank Morado, Glenda M Wright, Spencer J Greenwood
Hematodinium is a parasitic dinoflagellate of numerous crustacean species, including the economically important Atlantic snow crab, Chionoecetes opilio. The parasite was cultured in vitro in modified Nephrops medium at 0 °C and a partial characterization of the life stages was accomplished using light and transmission electron microscopy (TEM). In haemolymph from heavily infected snow crabs two life stages were detected; amoeboid trophonts and sporonts. During in vitro cultivation, several Hematodinium sp...
April 2015: Parasitology
Joel Buishas, Ian G Gould, Andreas A Linninger
Experimental evidence has cast doubt on the classical model of river-like cerebrospinal fluid (CSF) flow from the choroid plexus to the arachnoid granulations. We propose a novel model of water transport through the parenchyma from the microcirculation as driven by Starling forces. This model investigates the effect of osmotic pressure on water transport between the cerebral vasculature, the extracellular space (ECS), the perivascular space (PVS), and the CSF. A rigorous literature search was conducted focusing on experiments which alter the osmolarity of blood or ventricles and measure the rate of CSF production...
October 2014: Croatian Medical Journal
W G Bradley
CSF normally flows back and forth through the aqueduct during the cardiac cycle. During systole, the brain and intracranial vasculature expand and compress the lateral and third ventricles, forcing CSF craniocaudad. During diastole, they contract and flow through the aqueduct reverses. Hyperdynamic CSF flow through the aqueduct is seen when there is ventricular enlargement without cerebral atrophy. Therefore, patients presenting with clinical normal pressure hydrocephalus who have hyperdynamic CSF flow have been found to respond better to ventriculoperitoneal shunting than those with normal or decreased CSF flow...
May 2015: AJNR. American Journal of Neuroradiology
Masaki Ueno, Yoichi Chiba, Koichi Matsumoto, Toshitaka Nakagawa, Hiroshi Miyanaka
Intravascular substances invade extracellular spaces in the brain via endothelial cells in the sites without bloodbrain barrier (BBB) and move not only in the cerebrospinal fluid (CSF) but also in the interstitial fluid (ISF) of brain parenchyma adjacent to non-BBB sites. It is likely that CSF drains directly into the blood via arachnoid villi and granulations and also to lymph nodes via subarachnoid spaces in the brain and nasal lymphatics, whereas ISF drains to cervical lymph nodes through pathways along vascular wall of capillaries and arteries...
2014: Current Medicinal Chemistry
Haitham Dababneh, Waldo Guerrero, Siddhart Mehta, Mohammad Moussavi, Jawad F Kirmani
OBJECTIVE: Approximately 18,000 patients suffer from a subarachnoid hemorrhage (SAH) in the United States annually. SAH is a form of stroke and comprises 1%-5% of all strokes. Nearly 50% of all SAH cases end in fatality within 30 days of presentation; one of eight patients die before reaching a hospital. Those who survive often have neurological or cognitive impairment. METHODS: This case report describes the course of two patients who presented to the emergency department with aneurismal subarachnoid hemorrhage and received external ventricular drainage and endovascular treatment of their aneurysm...
September 2014: Journal of Vascular and Interventional Neurology
Anne-Sophie M C Monté, Jan L De Bleecker, Kurt Buccauw, Thierry Boulanger, Laurens J L De Cocker
No abstract text is available yet for this article.
September 2015: Acta Neurologica Belgica
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