Knowledge of the exact spatial distribution of brain tissues in images acquired by magnetic resonance imaging (MRI) is necessary to measure and compare the performance of segmentation algorithms. Currently available physical phantoms do not satisfy this requirement. State-of-the-art digital brain phantoms also fall short because they do not handle separately anatomical structures (e.g. basal ganglia) and provide relatively rough simulations of tissue fine structure and inhomogeneity. We present a software procedure for the construction of a realistic MRI digital brain phantom. The phantom consists of hydrogen nuclear magnetic resonance spin-lattice relaxation rate (R1), spin-spin relaxation rate (R2), and proton density (PD) values for a 24 × 19 × 15.5 cm volume of a "normal" head. The phantom includes 17 normal tissues, each characterized by both mean value and variations in R1, R2, and PD. In addition, an optional tissue class for multiple sclerosis (MS) lesions is simulated. The phantom was used to create realistic magnetic resonance (MR) images of the brain using simulated conventional spin-echo (CSE) and fast field-echo (FFE) sequences. Results of mono-parametric segmentation of simulations of sequences with different noise and slice thickness are presented as an example of possible applications of the phantom. The phantom data and simulated images are available online at http://lab.ibb.cnr.it/.
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http://dx.doi.org/10.1016/j.media.2011.01.004 | DOI Listing |
PLoS One
January 2025
Department of Convergence of Healthcare and Medicine, Ajou University Graduate School of Medicine, Suwon, South Korea.
Brain herniation can be a life-threatening condition, resulting in poor prognosis and higher fatality rates. We examined whether quantitative characteristics of sequential pupillary light reflex (PLR) could serve as biomarkers for identifying brain herniation in fatal acute stroke cases with anterior circulation involvement admitted to neurological intensive care unit (Neuro-ICU). Automatic pupillometer assessed PLR automatically every 4-6 hours, measuring eight specific features: NPi (Neurological pupil index) score, initial resting and constriction pupil size, constriction change, constriction velocity, constriction latency, and dilation velocity.
View Article and Find Full Text PDFNeuroinformatics
January 2025
Blue Brain Project, EPFL, Chemin des mines 9, 1202, Geneva, Switzerland.
Long-range axons are fundamental to brain connectivity and functional organization, enabling communication between different brain regions. Recent advances in experimental techniques have yielded a substantial number of whole-brain axonal reconstructions. While previous computational generative models of neurons have predominantly focused on dendrites, generating realistic axonal morphologies is more challenging due to their distinct targeting.
View Article and Find Full Text PDFJ Alzheimers Dis
January 2025
Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China.
Background: Plasma biomarkers demonstrated potential in identifying amyloid pathology in early Alzheimer's disease. Different subtypes of subjective cognitive decline (SCD) may lead to different cognitive impairment conversion risks.
Objective: To investigate the differences of plasma biomarkers in SCD subtypes individuals, which were unclear.
Cureus
December 2024
Department of Ophthalmology, Hospital University Kebangsaan Malaysia, Kuala Lumpur, MYS.
We report a rare case of a missed intracavernous internal carotid artery dissecting aneurysm occurring as a complication of the base of skull fracture with severe brain injury causing acute cavernous sinus syndrome with permanent vision loss. A 31-year-old Myanmar lady had an alleged motor vehicle accident and suffered severe traumatic brain injury with multiple intracranial bleeds, multiple facial bone and base of skull fractures, and limb fractures. At one week post-trauma, she had severe right eye proptosis with vision loss, ophthalmoplegia, chemosis, and high intraocular pressure.
View Article and Find Full Text PDFJ Neuroimaging
January 2025
Department of Otorhinolaryngology, School of Medicine, Kangwon National University, Chuncheon, Republic of Korea.
Background And Purpose: Tinnitus is a condition in which individuals perceive sounds, such as ringing or buzzing, without any external source. Although the exact cause is not fully understood, recent studies have indicated the involvement of nonauditory brain structures, including the limbic system. We aimed to compare the volumes of specific brain structures between patients with tinnitus and controls.
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