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Topic Review
Cranial Nerves of Facial Asymmetry
Symmetry of the face is the one of the most important features for the perception of attractiveness. The word “symmetry” derives from Greek and comes from “syn” (together) and “metron” (meter). Symmetry means that both sides of the face, right and left, are alike. The term “asymmetry” refers to dissimilarity between components, altering the balance between structures. Cranial nerve damage, especially the affection of oculomotor, trochlear, trigeminal, and facial nerves, may occur in many neurological conditions. The most common acquired causes of cranial nerve damage are cerebrovascular events, such as ischemic or haemorrhagic stroke.
  • 2.3K
  • 16 Jun 2022
Topic Review
Brain Tumor MR Image Segmentation
The precise segmentation of brain tumor images is a vital step towards accurate diagnosis and effective treatment of brain tumors. Magnetic Resonance Imaging (MRI) can generate brain images without tissue damage or skull artifacts, providing important discriminant information for clinicians in the study of brain tumors and other brain diseases. Segmentation methods of brain tumor MR image are mainly divided into three categories according to different segmentation principles: traditional segmentation methods, traditional machine learning-based segmentation methods and deep learning-based segmentation methods.
  • 1.3K
  • 23 Sep 2021
Topic Review
Pre-clinical Cerebral Perfusion MRI Techniques
Alterations to the cerebral microcirculation have been recognized to play a crucial role in the development of neurodegenerative disorders. However, the exact role of the microvascular alterations in the pathophysiological mechanisms often remains poorly understood. The early detection of changes in microcirculation and cerebral blood flow (CBF) can be used to get a better understanding of underlying disease mechanisms. This could be an important step towards the development of new treatment approaches. Animal models allow for the study of the disease mechanism at several stages of development, before the onset of clinical symptoms, and the verification with invasive imaging techniques. Specifically, pre-clinical magnetic resonance imaging (MRI) is an important tool for the development and validation of MRI sequences under clinically relevant conditions. This article reviews MRI strategies providing indirect non-invasive measurements of microvascular changes in the rodent brain that can be used for early detection and characterization of neurodegenerative disorders. The perfusion MRI techniques: Dynamic Contrast Enhanced (DCE), Dynamic Susceptibility Contrast Enhanced (DSC) and Arterial Spin Labeling (ASL), will be discussed, followed by less established imaging strategies used to analyze the cerebral microcirculation: Intravoxel Incoherent Motion (IVIM), Vascular Space Occupancy (VASO), Steady-State Susceptibility Contrast (SSC), Vessel size imaging, SAGE-based DSC, Phase Contrast Flow (PC) Quantitative Susceptibility Mapping (QSM) and quantitative Blood-Oxygenation-Level-Dependent (qBOLD). We will emphasize the advantages and limitations of each strategy, in particular on applications for high-field MRI in the rodent’s brain. 
  • 1.2K
  • 02 Jun 2021
Topic Review
Hippocampal Malrotation
Hippocampal malrotation (HIMAL) is an increasingly recognized neuroimaging feature but the clinical correlation and significance in epilepsies remain under debate.
  • 1.2K
  • 27 Apr 2021
Topic Review
Neurofibromatosis Type 1 and Brain
Neurofibromatosis type 1 (NF1), the most frequent phakomatosis and one of the most common inherited tumor predisposition syndromes, is characterized by several manifestations that pervasively involve central and peripheral nervous system structures. 
  • 1.2K
  • 20 Apr 2021
Topic Review
Magnetic Resonance Imaging in Infants with Hypoxic-Ischemic Encephalopathy
Hypoxic-ischemic encephalopathy (HIE) following perinatal asphyxia is a major cause of neurological sequelae in term and near-term infants. Despite therapeutic hypothermia, a significant number of infants still have adverse outcomes. Neuroimaging is the standard of care in infants with HIE to determine the nature and timing of the injury, guide further treatment, and predict neurodevelopmental outcomes. Cranial ultrasonography is helpful to assess the brain before initiation of therapeutic hypothermia to look for abnormalities suggestive of antenatal onset of injury or HIE mimics. However, magnetic resonance imaging (MRI) which includes diffusion-weighted imaging has become the gold standard to assess brain injury in newborns with HIE, and has an excellent prognostic utility. Magnetic resonance spectroscopy provides complementary metabolic information and has also been shown to be a reliable prognostic biomarker. Advanced imaging modalities, such as diffusion tensor imaging and arterial spin labeling, are increasingly being used to gain further information about the etiology and prognosis of brain injury in infants with HIE due to perinatal asphyxia. 
  • 997
  • 29 Mar 2022
Topic Review
[18F]FET PET in Glioma Recurrence
[18F]fluoroethyl-tyrosine (FET) is an artificial amino acid taken up into upregulated tumoral cells by the LAT system, independently of blood brain barrier leakage. FET is diffuse in Europe and has been shown to provide high sensitivity and specificity for glioma detection resulting in a reliable diagnostic tool for differentiating tumor recurrence/progression from treatment related changes.
  • 877
  • 19 Apr 2022
Topic Review
Lung Ultrasound
Lung ultrasound has become increasingly used in both adult and pediatric populations, allowing the rapid evaluation of many lung and pleura diseases. 
  • 846
  • 08 Apr 2021
Topic Review
Cerebrovascular Leak and Glymphatic Obstruction in Neurodegenerative Disease
New approaches are required to successfully intervene therapeutically in neurodegenerative diseases. Addressing the earliest phases of disease, blood brain barrier (BBB) leak before the accumulation of misfolded proteins has significant potential for success.
  • 808
  • 26 Oct 2021
Topic Review
Diffusion Tensor Imaging in Prognostic of Acute/Hyperacute Stroke
Clinical manifestation of stroke is characterized by great diversity, ranging from minor disability to considerable neurological impairment interfering with activities of daily living and even death. Prognostic ambiguity has stimulated the interest for implementing stroke recovery biomarkers, including those provided by structural neuroimaging techniques, i.e., diffusion tensor imaging (DTI) and tractography for the study of white matter (WM) integrity. Diffusion tensor imaging (DTI) is an extension of magnetic resonance imaging (MRI) for in vivo mapping of white matter (WM) directionality and organization, allowing the qualitative and quantitative evaluation of major WM tracts and their microstructural integrity. DTI is based on the random diffusion of water molecules. Research on DTI metrics as stroke outcome biomarker is not limited to the acute and subacute phases, as it is also implemented on chronic stroke patients. Direct visualization of long tracts and their potential disruption provides insight into pathogenesis of functional deficits in stroke survivors as well as compensatory mechanisms on a microstructural level. Such knowledge may elucidate which group of patients is most likely to benefit from rehabilitation, and even help personalize treatment plans after the acute stroke phase according to each individual’s needs. 
  • 787
  • 23 Nov 2022
Topic Review
In Vivo Brain Glutathione
Glutathione (GSH) is an important antioxidant implicated in several physiological functions, including the oxidation−reduction reaction balance and brain antioxidant defense against endogenous and exogenous toxic agents. Altered brain GSH levels may reflect inflammatory processes associated with several neurologic disorders. An accurate and reliable estimation of cerebral GSH concentrations could give a clear and thorough understanding of its metabolism within the brain, thus providing a valuable benchmark for clinical applications. 
  • 784
  • 21 Apr 2022
Topic Review
Boron Neutron Capture Therapy
Boron neutron capture therapy (BNCT) is a type of targeted radiotherapy. BNCT shows promising results in treating lung cancer, recurrent head and neck cancer, sarcomas, and high grade brain tumors.
  • 727
  • 29 Nov 2021
Topic Review
Autoimmune Demyelinating Diseases
The magnetic resonance characteristics of autoimmune demyelinating diseases are complex and represent a challenge for the radiologist. Expected and unexpected findings of magnetic resonance imaging examination for autoimmune demyelinating diseases were reported in order to provide a valuable approach for diagnosis.
  • 723
  • 18 Apr 2022
Topic Review
Ultrasound Technologies in Giant Cell Arteritis Diagnosis
Giant cell arteritis (GCA) is a primary autoimmune vasculitis that specifically affects medium-sized extracranial arteries, like superficial temporal arteries (TAs). The most important data to be considered for the ultrasound (US) diagnosis of temporal arteritis are stenosis, acute occlusions and “dark halo” sign, which represent the edema of the vascular wall. The vessel wall thickening of large vessels in GCA can be recognized by the US, which has high sensitivity and is facile to use. Ocular complications of GCA are common and consist especially of anterior arterial ischemic optic neuropathies or central retinal artery occlusion with sudden, painless, and sharp loss of vision in the affected eye. Color Doppler imaging of the orbital vessels (showing low-end diastolic velocities and a high resistance index) is essential to quickly differentiate the mechanism of ocular involvement (arteritic versus non-arteritic), since the characteristics of TAs on US do not correspond with ocular involvement on GCA. GCA should be cured immediately with systemic corticosteroids to avoid further visual loss of the eyes. 
  • 705
  • 30 Jan 2022
Topic Review
Two-Photon Imaging
Two-photon imaging (2PI) is a fluorescence-based laser scanning microscopy technique commonly used in studies across various fields of research, including neurobiology, embryology, and tissue engineering. In principle, it involves two infrared photons simultaneously exciting a single fluorophore in a sample, thereby causing it to emit light in a specific wavelength region, also called fluorescence emission spectrum. This fluorescence is normally detected in a wavelength region close to the maximum of this spectrum, allowing the sample to be identified based on its specific fluorescent characteristics.
  • 702
  • 15 Apr 2021
Topic Review
Aβ Optical Imaging in AD
Alzheimer’s disease (AD) is a multifactorial, irreversible, and incurable neurodegenerative disease. The main pathological feature of AD is the deposition of misfolded β-amyloid protein (Aβ) plaques in the brain. The abnormal accumulation of Aβ plaques leads to the loss of some neuron functions, further causing the neuron entanglement and the corresponding functional damage, which has a great impact on memory and cognitive functions. The imaging techniques for the clinical AD diagnosis currently mainly include computed tomography (CT), magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), positron emission tomography (PET), single-photon emission computed tomography (SPECT), magnetic resonance spectroscopy (MRS), and so on. Compared with clinical imaging modalities, optical imaging possesses many advantages (e.g., noninvasiveness, high sensitivity, low cost, high imaging speed, and the ability to carry out three-dimensional imaging with high spatial and temporal resolution), allowing for the detection of biological processes at the cellular or molecular level.
  • 674
  • 17 Aug 2021
Topic Review
Machine Learning in Image-Based Glioma Grading
Technological innovation has enabled the development of machine learning (ML) tools that aim to improve the practice of radiologists. In the last decade, ML applications to neuro-oncology have expanded significantly, with the pre-operative prediction of glioma grade using medical imaging as a specific area of interest. 
  • 665
  • 02 Jun 2022
Topic Review
Predictive Magnetic Resonance Imaging Biomarkers in Multiple Sclerosis
Multiple sclerosis (MS) is an inflammatory neurodegenerative disease of the central nervous system that poses a challenge to clinicians due to its remarkable inter- and intra-individual heterogeneity. MS still lacks specific humoral biomarkers for diagnosis, prognosis, or progression, but data derived from magnetic resonance imaging (MRI) measurements might represent our best predictive biomarkers to date.
  • 657
  • 28 Mar 2022
Topic Review
MRI CNS Atrophy Pattern
MRI shows the three archetypal patterns of CNS volume loss underlying progressive ataxias in vivo, namely spinal atrophy (SA), cortical cerebellar atrophy (CCA) and olivopontocerebellar atrophy (OPCA). In line with the neuropathological discoveries of the XIX and XX centuries, MRI confirms today that there are three fundamental distribution patterns of CNS atrophy underlying progressive ataxias in vivo. They are SA, CCA and OPCA and can be inherited or acquired. Although the present trend driven by molecular genetics advances is to split progressive ataxias into hundreds of sometimes very rare conditions, a simple clumping of them according to the MRI-based CNS atrophy pattern is possible and might help diagnosis, possibly improve physiopathology understanding and may even cause future studies to rethink therapies for these uncommon but disabling diseases.
  • 653
  • 28 Feb 2022
Topic Review
PET Imaging
PET imaging is being increasingly used to supplement MRI in the clinical management of brain tumors. The main radiotracers implemented in clinical practice include [18F]FDG, radiolabeled amino acids ([11C]MET, [18F]FDOPA, [18F]FET) and [68Ga]Ga-DOTA-SSTR, targeting glucose metabolism, L-amino-acid transport and somatostatin receptors expression, respectively. 
  • 652
  • 17 Feb 2022
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