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Prostate cancer
Published in Anju Sahdev, Sarah J. Vinnicombe, Husband & Reznek's Imaging in Oncology, 2020
Jurgen J Fütterer, Fillip Kossov, Henkjan Huisman
Magnetic resonance spectroscopic imaging is a method that can provide metabolic and functional information of the prostate gland and displays the relative concentrations of chemical compounds within the imaged voxels. At present, three-dimensional spectroscopic imaging is the most commonly used MRI spectroscopic technique. Although, MRSI is mostly performed in expert centres as a problem-solving tool.
Biomarkers for Organophosphate Poisoning: Physiological and Pathological Responses
Published in Brian J. Lukey, James A. Romano, Salem Harry, Chemical Warfare Agents, 2019
Arik Eisenkraft, Avshalom Falk, Kevin G. McGarry Jr.
The magnetic resonance of a given nucleus in a chemical environment is influenced by magnetic interactions with neighboring nuclei, shifting the frequencies of the emitted signals, a phenomenon known as chemical shift. These chemical shifts are expressed as a spectrum of signal intensity peaks (Buonocore and Maddock, 2015; Castillo et al., 1999). The chemical shifts are characteristic of the atom groups in which the studied nucleus resides; therefore, each peak is assigned to a specific molecular species, that is, metabolite, hosting the particular nucleus. The MR spectrum is used for the visualization and quantitation of metabolites with diagnostic or physiological importance. As the area under each peak is proportional to the analyte’s concentration, quantitation is carried out by either peak integration or peak fitting to a model (see a comprehensive review on quantitation approaches in Buonocore and Maddock, 2015). The two basic modes of MRS are single voxel spectrometry (SVS), in which a relatively large single voxel is scanned, and magnetic resonance spectroscopic imaging (MRSI) or chemical shift imaging (CSI) (Buonocore and Maddock, 2015), in which an array of small voxels is scanned to obtain information on the spatial distribution of metabolites and increase the spatial precision of the analysis. The main technical characteristics of the pulse sequences used in MRS are avoidance of interference by signals from adjacent zones and suppression of the signals from water (Buonocore and Maddock, 2015; Öz et al., 2014; van der Graaf, 2010).
Magnetic Resonance Imaging in the Detection of Prostate Cancer
Published in Ayman El-Baz, Gyan Pareek, Jasjit S. Suri, Prostate Cancer Imaging, 2018
Timothy D. McClure, Daniel Margolis, Peter N. Schlegel
Magnetic resonance spectroscopic imaging (MRSI) showed great promise in the detection of prostate cancer.22 However due to the complexity of the technique and difficulty in applying this technique to the general population MRSI is not a required component of the current PI-RADS version.23 The specifics of MRSI will not be discussed in this chapter as it is not currently being used clinically to detect prostate cancer in prostate mpMRI.
Neuroimaging in professional combat sports: consensus statement from the association of ringside physicians
Published in The Physician and Sportsmedicine, 2023
Newer MRI technology and acquisition sequences have improved the sensitivity of the MRI for detecting the stigmata of TBI, but not all sequences are routinely adopted or performed in clinical contexts, and some are presently strictly related to research due to high rates of false positives and false negatives. Among these is diffusion tensor imaging (DTI). Traumatic axonal injury is characterized by a reduction in fractional anisotropy (FA) on DTI. Magnetization transfer imaging (MTI), which applies radio frequency power only to the protons in the macromolecules of tissues rather than the protons in water, can add sensitivity to an MRI [1,8,9]. Magnetic source imaging (MSI), using a combination of MRI and magnetoencephalography (MEG), was found to be superior to using only an MRI in the detection of TBI [1,8,9]. Proton magnetic resonance spectroscopic imaging (1 H-MRSI) has been found to be a sensitive tool in detecting axonal injury in the corpus callosum of TBI patients [1,8,9]. Susceptibility-weighted imaging (SWI) and functional MRI (fMRI) techniques including arterial spin labeling (ASL) which can demonstrate changes in regional brain activation are newer MRI methods for better detection of TBI and microhemorrhages [8,9].
Corneal Subbasal Nerve Plexus Evaluation by in Vivo Confocal Microscopy in Multiple Sclerosis: A Potential New Biomarker
Published in Current Eye Research, 2021
Diogo Fernandes, Maria Luís, Joana Cardigos, Catarina Xavier, Marta Alves, Ana Luísa Papoila, João Paulo Cunha, Joana Tavares Ferreira
Along with the acute inflammatory episodes of demyelination, axonal degeneration is a fundamental component of MS and a major determinant of permanent neurological impairment.2 However, we still lack an accurate methodology to monitor axonal damage and possible nerve regeneration with treatment, which represents a major obstacle for new disease-modifying therapies development.3 Magnetic resonance spectroscopic imaging (MRSI) detects changes in metabolites such as N-acetyl aspartate, a marker of axonal integrity, being able to distinguish MS from healthy subjects.4,5 However, this methodology does not allow direct axon imaging, being also expensive and a time-consuming methodology, which limits its clinical application. Optic neuritis (ON) is the initial presentation in 20% of MS patients, while others will develop this inflammatory condition during disease course. Optical coherence tomography (OCT) studies reported a decreased peripapillary retinal nerve fibre layer (ppRNFL) thickness in MS patients.6–8 However, conflicting findings were found regarding the relationship between retinal nerve fibre layer (RNFL) thickness and Expanded Disability Status Scale (EDSS),9–11 the worldwide used method to quantify disability in MS and to monitor it over time. The occurrence of optic neuritis causes additional damage tothe optic nerve, which limits OCT usage as disease monitoring and progression biomarker.
The relation between cognitive dysfunction and diffusion tensor imaging parameters in traumatic brain injury
Published in Brain Injury, 2019
Robin Hanks, Scott Millis, Selena Scott, Ramtilak Gattu, Nolan B. O’Hara, Mark Haacke, Zhifeng Kou
DTI, susceptibility weighted imaging (SWI), magnetic resonance spectroscopic imaging, and baseline structural imaging (T1, T2, GRE, and T2 fluid-attenuated inversion recovery) sequences were collected on a 3-Tesla Siemens VERIO scanner with a 32-channel radio frequency head coil (Siemens Medical Solutions, Erlangen, Germany).