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Acquired Brain Injury Rehabilitation: What Can HRV Tell You?
Published in Herbert F. Jelinek, David J. Cornforth, Ahsan H. Khandoker, ECG Time Series Variability Analysis, 2017
Ian J. Baguley, Melissa T. Nott
Brain injuries are most usually classified according to their etiology. The first subdivision for brain injuries derives from their time of onset, with congenital brain injuries occurring before birth and ABIs accounting for all other forms of postpartum injury. Within ABI, two broad classes are recognized: traumatic and nontraumatic. The category of nontraumatic ABI is extremely eclectic, including etiologies such as infections, tumors, metabolic conditions, and various degenerative conditions (e.g., multiple sclerosis and dementia) (Entwistle and Newby 2013), along with environmental and other toxins. Among the most common nontraumatic ABI are cerebrovascular accidents (CVAs), otherwise known as stroke. Ischemic stroke follows blockage of the cerebral arterial supply by thrombus or plaque. Ischemic strokes are typically focal in nature and usually defined by clinical manifestations of large vessel syndromes specific to cerebrovascular territories (Eckerle and Southerland 2013). In contrast, hemorrhagic stroke, or intracerebral hemorrhage (ICH), refers to spontaneous bleeding into the brain parenchyma, often in the context of chronic hypertension or aneurysmal rupture, and accounts for about 5%–15% of acute strokes in Western countries (Kramer 2013). Hemorrhagic stroke can co-occur with subarachnoid hemorrhage (SAH), where bleeding occurs into the cerebrospinal fluid.
An Unsupervised Parametric Mixture Model for Automatic Cerebrovascular Segmentation
Published in Ayman El-Baz, Jasjit S. Suri, Cardiovascular Imaging and Image Analysis, 2018
Mohammed Ghazal, Yasmina Al Khalil, Ayman El-Baz
A stroke is defined as rapid disturbance in the cerebral blood flow, resulting in a short-term or permanent change in cerebral function [5]. Based on its pathological background, stroke can be classified as either ischemic or hemorrhagic. Ischemic stroke is the most frequent type, caused by a brief interruption of the blood supply to a certain part of the brain. Ischemic strokes can further be classified as thrombotic and embolic. Thrombotic strokes are characterized by a blood clot (thrombus) blocking an artery to the brain, hence interrupting regular blood flow. Embolic strokes are a result of a thrombus travelling from its original location such that it blocks an artery downstream. The damage occurred by an embolic stroke depends on the depth of the blockage manifestation in the artery [6]. In most cases, arteries affected by thrombotic or embolic strokes are not entirely blocked, enabling a small stream of blood to the brain. However, reduced blood flow decreases the amount of nutrients coming to the cells, which quickly affects their functionality, leading to symptoms of stroke occurring [7]. To treat ischemic strokes, the obstruction blocking the blood flow needs to be removed to restore the functionality of the cells and affected brain regions. A common treatment is a tissue plasminogen activator (tPA), which must be applied within a maximum of three hours from the occurrence of symptoms. However, only 3–5 percent of patients are able to reach the hospital in time for the treatment to be administered. Moreover, the tPA treatment increases the risk for intracranial hemorrhage. Other treatment options include intra-arterial thrombolysis with drugs or mechanical devices, carotid endarterectomy, and stenting of the cervical and intracranial vessels [8]. A hemorrhagic stroke can occur due to hypertension, fracture of an aneurysm or vascular deformity, as well as a consequence of anticoagulation medications. Two types of hemorrhage exist, an intracerebral hemorrhage and subarachnoid hemorrhage. An intracerebral hemorrhage occurs as a result of direct bleeding into the brain tissue, which further causes a lump within the brain. When bleeding expands into the cerebrospinal fluid areas around the brain, we refer to subarachnoid hemorrhage [1]. Due to intracranial pressure caused by bleeding, hemorrhagic stroke requires surgical treatment to prevent further damage and additional strokes. Stroke treatment additionally involves recovery and rehabilitation.
A comparative study on computational fluid dynamic, fluid-structure interaction and static structural analyses of cerebral aneurysm
Published in Engineering Applications of Computational Fluid Mechanics, 2022
Hong Tao Sun, Kam Yim Sze, Kwok Wing Chow, Anderson Chun On Tsang
Cerebral aneurysm (CA), also known as intracranial aneurysm, is a localized dilation of the blood vessel. Previous autopsy studies reported that CA occurrence ranges from 0.2–9.9% (Vega et al., 2002; Wiebers et al., 2004). The rupture of CAs can lead to subarachnoid haemorrhage (SAH) in which blood enters the space surrounding the brain. About 50% of the SAH cases are fatal (Broderick et al., 1994; Kaminogo et al., 2003; Winn et al., 2002). In general, a clinician would formulate the treatment of a pre-rupture CA based on the following factors of the patient: age, overall health, medical history, signs and symptoms, tolerance for specific medications, the morphology of the CA, etc.
Mechanical filtration of the cerebrospinal fluid: procedures, systems, and applications
Published in Expert Review of Medical Devices, 2023
Subarachnoid hemorrhage (SAH), either spontaneous or caused by a ruptured aneurysm, is a life-threatening event. Blood mixes with the CSF in the subarachnoid space (SAS) leading to increased intracranial pressure (ICP) and a series of secondary events in brain arteries. Initial treatment focuses on stabilizing the patient’s vital signs and stopping the bleeding (including aneurysm securement with neurovascular coiling or surgical removal of aneurysms when ruptured aneurysms are detected) and relieving the pressure on the brain when increased. Patients are then typically closely observed in the intensive care unit (ICU) to monitor complications and to check how the blood in the SAS reabsorbs with brain CT scans. Up to one-third of SAH patients develop complications after aneurysm securement, and morbidity and mortality due to these complications are high, with delayed ischemic neurological deficit reported in up to half of the cases with these complications [8]. It is generally acknowledged that clearance of blood products (such as blood cells, hemoglobin, oxyhemoglobin, and inflammatory proteins) from the CSF may be beneficial since these products mediate vasospasm and hydrocephalus. Early clearance of blood products has been shown to reduce the incidence of stroke, and the need for CSF shunting, resulting in a shorter hospital course. Thus, CSF filtration has been proposed to be applied shortly after SAH securement in post-aneurysmatic SAH, as a better approach than standard gravity-dependent drains [9]. To this aim, the PILLAR clinical trial was addressed to test CSF filtration in post-aneurysmal subarachnoid hemorrhage. The study showed positive results on the safety and feasibility of rapidly removing blood and blood breakdown products from the CSF [10].