In recent years many automatic methods have been developed to help physicians diagnose brain disorders, but the problem remains complex. In this paper we propose a method to segment brain structures on two 3D multi-modal MR images taken at different times (longitudinal acquisition). A bias field correction is performed with an adaptation of the Hidden Markov Chain (HMC) allowing us to take into account the temporal correlation in addition to spatial neighbourhood information. To improve the robustness of the segmentation of the principal brain structures and to detect Multiple Sclerosis Lesions as outliers the Trimmed Likelihood Estimator (TLE) is used during the process. The method is validated on 3D+t brain MR images.
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http://dx.doi.org/10.1109/EMBC.2014.6944677 | DOI Listing |
Brain Multiphys
December 2024
Department of Radiology, Mayo Clinic, Rochester, MN, USA.
Background And Purpose: Idiopathic normal pressure hydrocephalus (iNPH) is a cerebrospinal fluid (CSF) dynamics disorder as evidenced by the delayed ascent of radiotracers over the cerebral convexity on radionuclide cisternography. However, the exact mechanism causing this disruption remains unclear. Elucidating the pathophysiology of iNPH is crucial, as it is a treatable cause of dementia.
View Article and Find Full Text PDFWe developed a new sodium magnetic resonance fingerprinting ($^\text{23}\text{Na}$ MRF) method for the simultaneous mapping of $\text{T}_\text{1}$, $\text{T}_\text{2,long}^{*}$, $\text{T}_\text{2,short}^{*}$ and sodium density with built-in $\Delta\text{B}_{1}^{+}$ (radiofrequency transmission inhomogeneities) and $\Delta\text{f}_\text{0}$ corrections (frequency offsets). We based our $^\text{23}\text{Na}$ MRF implementation on a 3D FLORET sequence with 23 radiofrequency pulses. To capture the complex spin ${\frac{\text{3}}{\text{2}}}$ dynamics of the $^\text{23}\text{Na}$ nucleus, the fingerprint dictionary was simulated using the irreducible spherical tensor operators formalism.
View Article and Find Full Text PDFNMR Biomed
February 2025
High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.
Deuterium metabolic imaging (DMI) is an emerging Magnetic Resonance technique providing valuable insight into the dynamics of cellular glucose (Glc) metabolism of the human brain in vivo using deuterium-labeled (H) glucose as non-invasive tracer. Reliable concentration estimation of H-Glc and downstream synthesized neurotransmitters glutamate + glutamine (Glx) requires accurate knowledge of relaxation times, but so far tissue-specific T and T relaxation times (e.g.
View Article and Find Full Text PDFNMR Biomed
January 2025
Department of Radiological Sciences, University of California, Irvine, California, USA.
Myelin is essential in the nervous system of mammals. As the location and degree of myelin loss can reflect varied pathophysiological status, noninvasive measurement of myelin is of high importance. The magnetic resonance imaging (MRI) technique of myelin water fraction (MWF) derived from multi-echo gradient echo (MGRE) sequence is a promising tool for the quantification of myelin content due to the low specific absorption rate (SAR) compared with the spin-echo sequence, time efficiency, and wide availability.
View Article and Find Full Text PDFSmall
December 2024
Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, 300044, Taiwan.
The recruitment of T lymphocytes holds great potential for suppressing the most aggressive glioblastoma (GBM) recurrence with immunotherapy. However, the phenomenon of immune privilege and the generally low immunogenicity of vaccines often reduce the presence of lymphocytes within brain tumors, especially in brain tumor recurrence clusters. In this study, an implantable self-cascading catalytic therapy and antigen capture scaffold (CAS) that can boost catalytic therapy efficiency at post-surgery brain tumor and capture the antigens via urethane-polyethylene glycol-polypropylene glycol (PU-EO-PO) segments are developed for postoperative brain immunotherapy.
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