scholarly journals A.2 Clinical application of T1-w/T2-w ratio images for in vivo comparisons of myelin content in patients with trigeminal neuralgia

2021 ◽  
Vol 48 (s3) ◽  
pp. S14-S14
Author(s):  
C Li ◽  
PP Chu ◽  
P Hung ◽  
D Mikulis ◽  
M Hodaie
Keyword(s):  
Trigeminal Neuralgia ◽  
Imaging Techniques ◽  
Brain Regions ◽  
Clinical Tool ◽  
Non Invasive ◽  
Gaussian Curve ◽  
Normal Appearing White Matter ◽  
Curve Fit ◽  
Quantitative Analyses

Background: Novel magnetic resonance (MR) imaging techniques prompted the emergence of T1-w/T2-w images or “myelin-sensitive maps (MMs)” to measure myelin in vivo. However, acquisition-related variations in MR intensities prevent meaningful quantitative comparisons between MMs. We propose an improved pipeline to standardize MMs that is applied to patients with classic trigeminal neuralgia (CTN) and trigeminal neuralgia secondary to multiple sclerosis (MSTN). Methods: 3T scanner was used to obtain T1-w and T2-w images for 17 CTN and 17 MSTN patients. Template images were obtained from ICBM152 database. MS plaques and normal-appearing white matter (NAWM) were labelled. A Gaussian curve-fit was applied to the histogram of the intensity distribution of each patient image, and transformed to match the Gaussian curve-fit of the template image. Results: MM intensities were decreased within MS plaques, compared to NAWM in MSTN patients (p<0.001) and its corresponding regions in CTN patients (p<0.001). Qualitatively, the standardized patient image and its histogram better resembled the ICBM152 template. Conclusions: MM analysis revealed reduced myelin content in MS plaques compared to corresponding regions in CTN patients and surrounding NAWM in MSTN patients. The standardized MM serves as a non-invasive, clinical tool for quantitative analyses of myelin content between different brain regions and different patients in vivo.

scholarly journals In Vivo Imaging of Biodegradable Implants and Related Tissue Biomarkers

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2348
Author(s):  
Leon Riehakainen ◽  
Chiara Cavallini ◽  
Paolo Armanetti ◽  
Daniele Panetta ◽  
Davide Caramella ◽  
...  
Keyword(s):  
Imaging Modality ◽  
Imaging Techniques ◽  
Special Focus ◽  
Tissue Remodelling ◽  
Biodegradable Implant ◽  
Advantages And Disadvantages ◽  
Non Invasive ◽  
Positron Emission ◽  
Longitudinal Imaging

Non-invasive longitudinal imaging of osseointegration of bone implants is essential to ensure a comprehensive, physical and biochemical understanding of the processes related to a successful implant integration and its long-term clinical outcome. This study critically reviews the present imaging techniques that may play a role to assess the initial stability, bone quality and quantity, associated tissue remodelling dependent on implanted material, implantation site (surrounding tissues and placement depth), and biomarkers that may be targeted. An updated list of biodegradable implant materials that have been reported in the literature, from metal, polymer and ceramic categories, is provided with reference to the use of specific imaging modalities (computed tomography, positron emission tomography, ultrasound, photoacoustic and magnetic resonance imaging) suitable for longitudinal and non-invasive imaging in humans. The advantages and disadvantages of the single imaging modality are discussed with a special focus on preclinical imaging for biodegradable implant research. Indeed, the investigation of a new implant commonly requires histological examination, which is invasive and does not allow longitudinal studies, thus requiring a large number of animals for preclinical testing. For this reason, an update of the multimodal and multi-parametric imaging capabilities will be here presented with a specific focus on modern biomaterial research.

scholarly journals Focal changes in brain energy and phospholipid metabolism in first-episode schizophrenia

2004 ◽  
Vol 184 (5) ◽  
pp. 409-415 ◽  
Author(s):  
J. Eric Jensen ◽  
Jodi Miller ◽  
Peter C. Williamson ◽  
Richard W J. Neufeld ◽  
Ravi S. Menon ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Imaging Techniques ◽  
High Energy ◽  
Brain Regions ◽  
Anterior Cingulate ◽  
First Episode ◽  
Resonance Spectroscopy ◽  
Membrane Breakdown ◽  
First Episode Schizophrenia

BackgroundMembrane phospholipid and high-energy abnormalities measured with phosphorus magnetic resonance spectroscopy (31P-MRS) have been reported in patients with schizophrenia in several brain regions.AimsUsing improved imaging techniques, previously inaccessible brain regions were examined in patients with first-episode schizophrenia and healthy volunteers with 4.0 T 31P-MRS.MethodBrain spectra were collected in vivo from 15 patients with first-episode schizophrenia and 15 healthy volunteers from 15 cm3 effective voxels in the thalamus, cerebellum, hippocampus, anterior/posterior cingulate, prefrontal cortex and parieto-occipital cortex.ResultsPeople with first-episode schizophrenia showed increased levels of glycerophosphocholine in the anterior cingulate. Inorganic phosphate, phosphocreatine and adenosine triphosphate concentrations were also increased in the anterior cingulate in this group.ConclusionsThe increased phosphodiester and high-energy phosphate levels in the anterior cingulate of brains of people with first-episode schizophrenia may indicate neural overactivity in this region during the early stages of the illness, resulting in increased excitotoxic neural membrane breakdown.

scholarly journals Study of Osteocyte Behavior by High-Resolution Intravital Imaging Following Photo-Induced Ischemia

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2874
Author(s):  
Hengfeng Yuan ◽  
Wen Jiang ◽  
Yuanxin Chen ◽  
Betty Kim
Keyword(s):  
Imaging Techniques ◽  
Avascular Osteonecrosis ◽  
Functional Changes ◽  
Cellular Processes ◽  
Non Invasive ◽  
Behavioral Dynamics ◽  
Bony Anatomy ◽  
Magnetic Resonance Imaging Mri

Ischemic injuries and local hypoxia can result in osteocytes dysfunction and play a key role in the pathogenesis of avascular osteonecrosis. Conventional imaging techniques including magnetic resonance imaging (MRI) and computed tomography (CT) can reveal structural and functional changes within bony anatomy; however, characterization of osteocyte behavioral dynamics in the setting of osteonecrosis at the single cell resolution is limited. Here, we demonstrate an optical approach to study real-time osteocyte functions in vivo. Using nicotinamide adenine dinucleotide (NADH) as a biomarker for metabolic dynamics in osteocytes, we showed that NADH level within osteocytes transiently increase significantly after local ischemia through non-invasive photo-induced thrombosis of afferent arterioles followed by a steady decline. Our study presents a non-invasive optical approach to study osteocyte behavior through the modulation of local environmental conditions. Thus it provides a powerful toolkit to study cellular processes involved in bone pathologies in vivo.

scholarly journals 4D flow MRI for non-invasive measurement of blood flow in the brain: A systematic review

2020 ◽  
pp. 0271678X2095201
Author(s):  
Alasdair G Morgan ◽  
Michael J Thrippleton ◽  
Joanna M Wardlaw ◽  
Ian Marshall
Keyword(s):  
Blood Flow ◽  
Imaging Techniques ◽  
Acquisition Time ◽  
4D Flow ◽  
Non Invasive ◽  
Major Vessel ◽  
Dynamic Velocity ◽  
Blood Flow Dynamics ◽  
Cerebrovascular Imaging

The brain’s vasculature is essential for brain health and its dysfunction contributes to the onset and development of many dementias and neurological disorders. While numerous in vivo imaging techniques exist to investigate cerebral haemodynamics in humans, phase-contrast magnetic resonance imaging (MRI) has emerged as a reliable, non-invasive method of quantifying blood flow within intracranial vessels. In recent years, an advanced form of this method, known as 4D flow, has been developed and utilised in patient studies, where its ability to capture complex blood flow dynamics within any major vessel across the acquired volume has proved effective in collecting large amounts of information in a single scan. While extremely promising as a method of examining the vascular system’s role in brain-related diseases, the collection of 4D data can be time-consuming, meaning data quality has to be traded off against the acquisition time. Here, we review the available literature to examine 4D flow’s capabilities in assessing physiological and pathological features of the cerebrovascular system. Emerging techniques such as dynamic velocity-encoding and advanced undersampling methods, combined with increasingly high-field MRI scanners, are likely to bring 4D flow to the forefront of cerebrovascular imaging studies in the years to come.

scholarly journals Non-Invasive Assessment of Intravascular Pressure Gradients: A Review of Current and Proposed Novel Methods

Diagnostics ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 5 ◽  
Author(s):  
Tin-Quoc Nguyen ◽  
Kristoffer Hansen ◽  
Thor Bechsgaard ◽  
Lars Lönn ◽  
Jørgen Jensen ◽  
...  
Keyword(s):  
Stokes Equations ◽  
Imaging Techniques ◽  
Navier Stokes ◽  
Pressure Gradients ◽  
Bernoulli Equation ◽  
Strong Correlations ◽  
Navier Stokes Equations ◽  
Non Invasive ◽  
Invasive Techniques

Invasive catheterization is associated with a low risk of serious complications. However, although it is the gold standard for measuring pressure gradients, it induces changes to blood flow and requires significant resources. Therefore, non-invasive alternatives are urgently needed. Pressure gradients are routinely estimated non-invasively in clinical settings using ultrasound and calculated with the simplified Bernoulli equation, a method with several limitations. A PubMed literature search on validation of non-invasive techniques was conducted, and studies were included if non-invasively estimated pressure gradients were compared with invasively measured pressure gradients in vivo. Pressure gradients were mainly estimated from velocities obtained with Doppler ultrasound or magnetic resonance imaging. Most studies used the simplified Bernoulli equation, but more recent studies have employed the expanded Bernoulli and Navier–Stokes equations. Overall, the studies reported good correlation between non-invasive estimation of pressure gradients and catheterization. Despite having strong correlations, several studies reported the non-invasive techniques to either overestimate or underestimate the invasive measurements, thus questioning the accuracy of the non-invasive methods. In conclusion, more advanced imaging techniques may be needed to overcome the shortcomings of current methods.

scholarly journals Point-of-Care Pathology with Miniature Microscopes

2011 ◽  
Vol 34 (3) ◽  
pp. 81-98 ◽  
Author(s):  
Jonathan T. C. Liu ◽  
Nathan O. Loewke ◽  
Michael J. Mandella ◽  
Richard M. Levenson ◽  
James M. Crawford ◽  
...  
Keyword(s):  
Real Time ◽  
New Technologies ◽  
Point Of Care ◽  
Definitive Treatment ◽  
Clinical Tool ◽  
Training Requirements ◽  
Non Invasive ◽  
Complex Process ◽  
Molecular Indicators

Advances in optical designs are enabling the development of miniature microscopes that can examine tissue in situ for early anatomic and molecular indicators of disease, in real time, and at cellular resolution. These new devices will lead to major changes in how diseases are detected and managed, driving a shift from today's diagnostic paradigm of biopsy followed by histopathology and recommended therapy, to non-invasive point-of-care diagnosis with possible same-session definitive treatment. This shift may have major implications for the training requirements of future physicians to enable them to interpret real-timein vivomicroscopic data, and will also shape the emerging fields of telepathology and telemedicine. Implementation of new technologies into clinical practice is a complex process that requires bridging gaps between clinicians, engineers and scientists. This article provides a forward-looking discussion of these issues, with a focus on malignant and pre-malignant lesions, by first highlighting some of the clinical areas where point-of-carein vivomicroscopy could address unmet needs, and then by reviewing the technological challenges that are being addressed, or need to be addressed, forin vivomicroscopy to become a standard clinical tool.

scholarly journals Non-Invasive measurement of the cerebral metabolic rate of oxygen using MRI in rodents

2021 ◽  
Vol 6 ◽  
pp. 109
Author(s):  
Tobias C Wood ◽  
Diana Cash ◽  
Eilidh MacNicol ◽  
Camilla Simmons ◽  
Eugene Kim ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Imaging Techniques ◽  
Glucose Consumption ◽  
Oxygen Metabolism ◽  
Oxygen Extraction Fraction ◽  
Strongly Correlated ◽  
Non Invasive ◽  
Cerebral Metabolic Rate ◽  
Invasive Measurement

Malfunctions of oxygen metabolism are suspected to play a key role in a number of neurological and psychiatric disorders, but this hypothesis cannot be properly investigated without an in-vivo non-invasive measurement of brain oxygen consumption. We present a new way to measure the Cerebral Metabolic Rate of Oxygen (CMRO2) by combining two existing magnetic resonance imaging techniques, namely arterial spin-labelling and oxygen extraction fraction mapping. This method was validated by imaging rats under different anaesthetic regimes and was strongly correlated to glucose consumption measured by autoradiography.

scholarly journals A Bright Future for Fluorescence Imaging of Fungi in Living Hosts

2019 ◽  
Vol 5 (2) ◽  
pp. 29 ◽  
Author(s):  
Ambre Chapuis ◽  
Elizabeth Ballou ◽  
Donna MacCallum
Keyword(s):  
Mouse Models ◽  
Fluorescent Proteins ◽  
Imaging Techniques ◽  
Post Mortem ◽  
New Techniques ◽  
Ethical Concerns ◽  
Non Invasive ◽  
Reporter Proteins ◽  
Invasive Techniques

Traditional in vivo investigation of fungal infection and new antifungal therapies in mouse models is usually carried out using post mortem methodologies. However, biomedical imaging techniques focusing on non-invasive techniques using bioluminescent and fluorescent proteins have become valuable tools. These new techniques address ethical concerns as they allow reduction in the number of animals required to evaluate new antifungal therapies. They also allow better understanding of the growth and spread of the pathogen during infection. In this review, we concentrate on imaging technologies using different fungal reporter proteins. We discuss the advantages and limitations of these different reporters and compare the efficacy of bioluminescent and fluorescent proteins for fungal research.

scholarly journals IMAGING TECHNIQUES FOR THE EVALUATION OF GRAPES IN WITHERING FOR AMARONE WINE PRODUCTION

2018 ◽  
Author(s):  
Barbara Cisterna ◽  
Federico Boschi ◽  
Anna Cleta Croce ◽  
Rachele Podda ◽  
Serena Zanzoni ◽  
...  
Keyword(s):  
Optical Properties ◽  
Ex Vivo ◽  
Imaging Techniques ◽  
Wine Production ◽  
Invasive Approach ◽  
Non Invasive ◽  
Innovative Materials ◽  
Amarone Wine

Optical Imaging (OI) is an emerging field developed in recent years which can be a very versatile, fast and non-invasive approach for the acquisition of images of  small (few centimetres) sized samples, such as layers of cells (in vitro), small animals (in vivo), animal organs (ex vivo) and innovative materials. OI was primarily developed for biomedical applications to study the progression of some pathologies and to assess the efficacy of new pharmaceutical compounds. Here we applied the OI technique to a completely new field: the study of food optical properties. In this case we exploited the optical properties of endogenous molecules, which are generally considered responsible of a background noise affecting the investigation. Here we used this sort of “noise”, named autofluorescence, to obtain information on the drying of Corvinone grapes employed for Amarone wine production. OI can provide interesting information and, inserted in a multimodal approach, it may be a real support to other techniques in the description of a biological phenomenon.

scholarly journals Comparison of Different Polarization Sensitive Second Harmonic Generation Imaging Techniques

2019 ◽  
Vol 2 (2) ◽  
pp. 49 ◽  
Author(s):  
Mehdi Alizadeh ◽  
Masood Ghotbi ◽  
Pablo Loza-Alvarez ◽  
David Merino
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Imaging Techniques ◽  
Image Plane ◽  
Excitation Beam ◽  
Non Invasive ◽  
Second Harmonic Generation Imaging ◽  
First Time

Polarization sensitive second harmonic generation (pSHG) microscopy is an imaging technique able to provide, in a non-invasive manner, information related to the molecular structure of second harmonic generation (SHG) active structures, many of which are commonly found in biological tissue. The process of acquiring this information by means of pSHG microscopy requires a scan of the sample using different polarizations of the excitation beam. This process can take considerable time in comparison with the dynamics of in vivo processes. Fortunately, single scan polarization sensitive second harmonic generation (SS-pSHG) microscopy has also been reported, and is able to generate the same information at a faster speed compared to pSHG. In this paper, the orientation of second harmonic active supramolecular assemblies in starch granules is obtained on by means of pSHG and SS-pSHG. These results are compared in the forward and backward directions, showing a good agreement in both techniques. This paper shows for the first time, to the best of the authors’ knowledge, data acquired using both techniques over the exact same sample and image plane, so that they can be compared pixel-to-pixel.

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