scholarly journals Clinically feasible brain morphometric similarity network construction approaches with restricted magnetic resonance imaging acquisitions

2020 ◽  
Vol 4 (1) ◽  
pp. 274-291
Author(s):  
Daniel J. King ◽  
Amanda G. Wood
Keyword(s):  
Multimodal Imaging ◽  
Structural Mri ◽  
Resonance Imaging ◽  
Network Construction ◽  
Future Studies ◽  
Anatomical Features ◽  
Developmental Neuroscience ◽  
Human Connectome Project ◽  
Similarity Networks ◽  
Potential Tool

Morphometric similarity networks (MSNs) estimate organization of the cortex as a biologically meaningful set of similarities between anatomical features at the macro- and microstructural level, derived from multiple structural MRI (sMRI) sequences. These networks are clinically relevant, predicting 40% variance in IQ. However, the sequences required (T1w, T2w, DWI) to produce these networks are longer acquisitions, less feasible in some populations. Thus, estimating MSNs using features from T1w sMRI is attractive to clinical and developmental neuroscience. We studied whether reduced-feature approaches approximate the original MSN model as a potential tool to investigate brain structure. In a large, homogenous dataset of healthy young adults (from the Human Connectome Project, HCP), we extended previous investigations of reduced-feature MSNs by comparing not only T1w-derived networks, but also additional MSNs generated with fewer MR sequences, to their full acquisition counterparts. We produce MSNs that are highly similar at the edge level to those generated with multimodal imaging; however, the nodal topology of the networks differed. These networks had limited predictive validity of generalized cognitive ability. Overall, when multimodal imaging is not available or appropriate, T1w-restricted MSN construction is feasible, provides an appropriate estimate of the MSN, and could be a useful approach to examine outcomes in future studies.

scholarly journals Clinically-Feasible Brain Morphometric Similarity Network Construction Approaches with Restricted Magnetic Resonance Imaging Acquisitions and their Relationship with Cognition

2019 ◽  
Author(s):  
Daniel J. King ◽  
Amanda Wood
Keyword(s):  
Developmentally Appropriate ◽  
Structural Connectivity ◽  
Developmental Neuroscience ◽  
Architectural Features ◽  
Human Connectome Project ◽  
Valid Estimate ◽  
Mri Sequences ◽  
Project Data ◽  
Potential Tool

Morphometric Similarity Networks (MSNs) estimate structural 'connectivity' as a biologically meaningful set of statistical similarities between cyto-architectural features derived in-vivo from multiple MRI sequences. These networks have shown to be clinically relevant, predicting 40% variance in IQ. However, the sequences required (T1w and T2w 3D anatomical, DWI) to produce these networks typically have long acquisition times, which are less feasible in some populations. Thus, estimating MSNs using features from only a T1w MRI is attractive to both clinical and developmental neuroscience. We aimed to determine whether reduced-feature approaches approximate the original MSN model as a potential tool to investigate brain structure. Using Human Connectome Project data, we extended previous investigations of reduced-feature MSNs by comparing not only T1w-derived networks but additional MSNs generated with fewer MR sequences to their full acquisition counterparts. We produce MSNs which are highly similar at the edge-level, to those generated with multi-modal imaging. We also find that, regardless of the number of features, these networks have limited predictive validity of generalised cognitive ability scores in contrast to previous research. Overall, settings in which multi-modal imaging is not available or clinically/developmentally appropriate, T1w-restricted MSN construction provides a valid estimate of the MSN.

scholarly journals Idiopathic Free-Floating Thrombus of the Common Carotid Artery

2002 ◽  
Vol 29 (1) ◽  
pp. 97-99 ◽  
Author(s):  
Brian Silver ◽  
Irene Gulka ◽  
Michael Nicolle ◽  
Ramesh Sahjpaul ◽  
Vladimir Hachinski
Keyword(s):  
Carotid Artery ◽  
Common Carotid Artery ◽  
Multimodal Imaging ◽  
Doppler Ultrasonography ◽  
Resonance Imaging ◽  
Wall Defect ◽  
Floating Thrombus ◽  
Weighted Magnetic Resonance Imaging ◽  
The Common ◽  
One Year

Background:The observation of an intraluminal common carotid artery thrombus overlying a wall defect at ultrasonography or angiography is unusual. To our knowledge, there are no previous reports of a free-floating thrombus in the common carotid artery.Case Report:A 45-year-old woman who was previously healthy and on no medications presented with acute hemiparesis and aphasia. Following testing that included carotid duplex and trancranial Doppler ultrasonography, diffusion-weighted magnetic resonance imaging, and digital subtraction angiography, the patient underwent emergency open embolectomy. No underlying wall defect was seen at the time of imaging or surgery. No obvious hypercoagulable state could be identified. Her NIH Stroke Scale score improved from 26 at admission to 2 at three months and 1 at one year.Conclusions:Multimodal imaging may have improved diagnosis and management in this patient with a unique finding. The source of the thrombus remains obscure.

Main anatomical features of the calcarine sulcus: a 3D magnetic resonance imaging at 3T study

2018 ◽  
Vol 41 (2) ◽  
pp. 181-186
Author(s):  
Ahmad Rachid El Mohamad ◽  
Laurent Tatu ◽  
Thierry Moulin ◽  
Sami Fadoul ◽  
Fabrice Vuillier
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Resonance Imaging ◽  
Anatomical Features ◽  
3D Magnetic Resonance Imaging

scholarly journals Imaging and Molecular Mechanisms of Alzheimer’s Disease: A Review

2018 ◽  
Vol 19 (12) ◽  
pp. 3702 ◽  
Author(s):  
Grazia Femminella ◽  
Tony Thayanandan ◽  
Valeria Calsolaro ◽  
Klara Komici ◽  
Giuseppe Rengo ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Multimodal Imaging ◽  
Molecular Mechanisms ◽  
Imaging Techniques ◽  
Structural Mri ◽  
Imaging Biomarkers ◽  
Significant Burden ◽  
Made In

Alzheimer’s disease is the most common form of dementia and is a significant burden for affected patients, carers, and health systems. Great advances have been made in understanding its pathophysiology, to a point that we are moving from a purely clinical diagnosis to a biological one based on the use of biomarkers. Among those, imaging biomarkers are invaluable in Alzheimer’s, as they provide an in vivo window to the pathological processes occurring in Alzheimer’s brain. While some imaging techniques are still under evaluation in the research setting, some have reached widespread clinical use. In this review, we provide an overview of the most commonly used imaging biomarkers in Alzheimer’s disease, from molecular PET imaging to structural MRI, emphasising the concept that multimodal imaging would likely prove to be the optimal tool in the future of Alzheimer’s research and clinical practice.

scholarly journals Surgical and Radiological Anatomy of the Medial Patellofemoral Ligament: A Magnetic Resonance Imaging and Cadaveric Study

Diagnostics ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2076
Author(s):  
Vasileios Raoulis ◽  
Apostolos Fyllos ◽  
Michail E. Klontzas ◽  
Dimitrios Chytas ◽  
Vasileios Mitrousias ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Medial Patellofemoral Ligament ◽  
Three Dimensional ◽  
Quadriceps Tendon ◽  
Dimensional Structure ◽  
Resonance Imaging ◽  
Average Width ◽  
Radiological Anatomy ◽  
Anatomical Features

The purpose of this study was to compare the measurement of several anatomical features of the medial patellofemoral ligament (MPFL) between magnetic resonance imaging (MRI) and by direct fashion during dissection. We hypothesized that the measurements between these two techniques would agree. MRI of 30 fresh-frozen cadaveric knees was followed by dissection. MPFL patella and femoral attachment were evaluated; their shape, length, and width were measured; and measurements were compared. MRI was deemed unreliable for the determination of several of the aforementioned anatomical features. Important findings include: (a) observations on MPFL attachment at medial patella side and attachment to quadriceps were identical between dissection and MRI; (b) average width at patella insertion was significantly different between the two methods (p = 0.002); and (c) an attachment to the quadriceps tendon was present in 20/30 specimens and d. detailed measurements of a thin, non-linear, and three-dimensional structure, such as the MPFL, cannot be performed on MRI, due to technical difficulties. This anatomical radiological study highlights the shape, anatomical measurements (length and width), and attachment of the MPFL using a relatively large cadaveric sample and suggests that MRI is not reliable for detailed imaging of its three-dimensional anatomy.

scholarly journals Transcranial direct current stimulation with functional magnetic resonance imaging: a detailed validation and operational guide

2021 ◽  
Vol 6 ◽  
pp. 143
Author(s):  
Davide Nardo ◽  
Megan Creasey ◽  
Clive Negus ◽  
Katerina Pappa ◽  
Alphonso Reid ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Future Studies ◽  
Direct Current Stimulation ◽  
Technical Challenges

Introduction: Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique used to modulate human brain and behavioural function in both research and clinical interventions. The combination of functional magnetic resonance imaging (fMRI) with tDCS enables researchers to directly test causal contributions of stimulated brain regions, answering questions about the physiology and neural mechanisms underlying behaviour. Despite the promise of the technique, advances have been hampered by technical challenges and methodological variability between studies, confounding comparability/replicability. Methods: Here tDCS-fMRI at 3T was developed for a series of experiments investigating language recovery after stroke. To validate the method, one healthy volunteer completed an fMRI paradigm with three conditions: (i) No-tDCS, (ii) Sham-tDCS, (iii) 2mA Anodal-tDCS. MR data were analysed in SPM12 with region-of-interest (ROI) analyses of the two electrodes and reference sites. Results: Quality assessment indicated no visible signal dropouts or distortions introduced by the tDCS equipment. After modelling scanner drift, motion-related variance, and temporal autocorrelation, we found no field inhomogeneity in functional sensitivity metrics across conditions in grey matter and in the three ROIs. Discussion: Key safety factors and risk mitigation strategies that must be taken into consideration when integrating tDCS into an fMRI environment are outlined. To obtain reliable results, we provide practical solutions to technical challenges and complications of the method. It is hoped that sharing these data and SOP will promote methodological replication in future studies, enhancing the quality of tDCS-fMRI application, and improve the reliability of scientific results in this field. Conclusions: The method and data provided here provide a technically safe, reliable tDCS-fMRI procedure to obtain high quality MR data. The detailed framework of the Standard Operation Procedure SOP (https://doi.org/10.5281/zenodo.4606564) systematically reports the technical and procedural elements of our tDCS-fMRI approach, which we hope can be adopted and prove useful in future studies.

scholarly journals Functional connectivity of fMRI using differential covariance predicts structural connectivity and behavioral reaction times

2021 ◽  
Author(s):  
Yusi Chen ◽  
Qasim Bukhari ◽  
Tiger Wutu Lin ◽  
Terrence J Sejnowski
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Connectivity ◽  
Resting State ◽  
Structural Connectivity ◽  
Reaction Times ◽  
Resonance Imaging ◽  
Brain Areas ◽  
Human Connectome Project ◽  
Wide Range

Recordings from resting state functional magnetic resonance imaging (rs-fMRI) reflect the influence of pathways between brain areas. A wide range of methods have been proposed to measure this functional connectivity (FC), but the lack of ''ground truth'' has made it difficult to systematically validate them. Most measures of FC produce connectivity estimates that are symmetrical between brain areas. Differential covariance (dCov) is an algorithm for analyzing FC with directed graph edges. Applied to synthetic datasets, dCov-FC was more effective than covariance and partial correlation in reducing false positive connections and more accurately matching the underlying structural connectivity. When we applied dCov-FC to resting state fMRI recordings from the human connectome project (HCP) and anesthetized mice, dCov-FC accurately identified strong cortical connections from diffusion Magnetic Resonance Imaging (dMRI) in individual humans and viral tract tracing in mice. In addition, those HCP subjects whose rs-fMRI were more integrated, as assessed by a graph-theoretic measure, tended to have shorter reaction times in several behavioral tests. Thus, dCov-FC was able to identify anatomically verified connectivity that yielded measures of brain integration causally related to behavior.

scholarly journals Left ventricular pseudoaneurysm: an inadvertent consequence of COVID-19—a case report

2021 ◽  
Vol 5 (7) ◽  
Author(s):  
Stephen Brennan ◽  
Saadah Sulong ◽  
Matthew Barrett
Keyword(s):  
Multimodal Imaging ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Left Ventricular ◽  
Medical Complications ◽  
Mechanical Complication ◽  
Resonance Imaging ◽  
Left Ventricular Pseudoaneurysm ◽  
Non Invasive ◽  
Case Summary

Abstract Background Left ventricular pseudoaneurysm (LVP) is an uncommon but serious mechanical complication of acute myocardial infarction (AMI). The immediate medical complications of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are well recognized, but its indirect effect on patients and healthcare systems is potentially less perceivable. Case summary In this report, a 72-year-old man who was anxious about attending hospital during the SARS-CoV-2 pandemic was eventually found to have a total right coronary artery occlusion after a delayed emergency department presentation. He ultimately developed severe symptomatic heart failure and cardiac magnetic resonance imaging (CMR) revealed that a large LVP with concomitant severe ischaemic mitral regurgitation had evolved from his infarct. The patient was successfully discharged home after the surgical replacement of his mitral valve and repair of his LVP. Discussion This case highlights a salient downstream effect of Coronavirus disease 2019 (COVID-19): the delay in presentation, diagnosis, and management of common treatable conditions such as AMI. It also underscores the importance of non-invasive multimodal imaging on the timely identification of the mechanical complications of AMI. In particular, CMR can play a crucial role in the characterization and management of LVP.

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