We would like to thank the Canadian Institutes of Health Research (CIHR) and the Ontario Neurotrauma Foundation (ONF) who have provided funding for this research.

<ol>
	<li>Browne, G. J., Lam, L. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Concussive+head+injury+in+children+and+adolescents+related+to+sports+and+other+leisure+physical+activities.">Concussive head injury in children and adolescents related to sports and other leisure physical activities.</a> Br. J .Sports Med. 40, 163-168 (2006).</li><li>McCrory, P., Collie, A., Anderson, V., Davis, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Can+we+manage+sport+related+concussion+in+children+the+same+as+in+adults.">Can we manage sport related concussion in children the same as in adults.</a> Br. J .Sports Med. 38, 516-519 (2004).</li><li>Brolinson, P. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+linear+head+accelerations+from+collegiate+football+impacts.">Analysis of linear head accelerations from collegiate football impacts.</a> Curr. Sports Med. Rep. 5, 23-28 (2006).</li><li>Duma, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+real-time+head+accelerations+in+collegiate+football+players.">Analysis of real-time head accelerations in collegiate football players.</a> Clin. J. Sport Med. 15, 3-8 (2005).</li><li>Schnebel, B., Gwin, J. T., Anderson, S., Gatlin, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+study+of+head+impacts+in+football:+a+comparison+of+National+Collegiate+Athletic+Association+Division+I+versus+high+school+impacts.">In vivo study of head impacts in football: a comparison of National Collegiate Athletic Association Division I versus high school impacts.</a> Neurosurgery. 60, 490-495 (2007).</li><li>Chen, J. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+abnormalities+in+symptomatic+concussed+athletes:+an+fMRI+study.">Functional abnormalities in symptomatic concussed athletes: an fMRI study.</a> Neuroimage. 22, 68-82 (2004).</li><li>Glover, G. H., Law, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spiral-in/out+BOLD+fMRI+for+increased+SNR+and+reduced+susceptibility+artifacts.">Spiral-in/out BOLD fMRI for increased SNR and reduced susceptibility artifacts.</a> Magn. Reson. Med. 46, 515-522 (2001).</li><li>Smith, S. M., Jenkinson, M., Johansen-Berg, H., Rueckert, D., Nichols, T. E., Mackay, C. E., Watkins, K. E., Ciccarelli, O., Cader, M. Z., Matthews, P. M., Behrens, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tract-based+spatial+statistics:+voxelwise+analysis+of+multi-subject+diffusion+data.">Tract-based spatial statistics: voxelwise analysis of multi-subject diffusion data.</a> Neuroimage. 31, 1487-1505 (2006).</li><li>Gibson, E., Gao, F., Black, S. E., Lobaugh, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automatic+Segmentation+of+White+Matter+Hyperintensities+in+FLAIR+images+at+3T.">Automatic Segmentation of White Matter Hyperintensities in FLAIR images at 3T.</a> J. Magn. Reson. Imaging. , (2009).</li><li>McIntosh, A. R., Bookstein, F. L., Haxby, J. V., Grady, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatial+pattern+analysis+of+functional+brain+images+using+Partial+Least+Squares.">Spatial pattern analysis of functional brain images using Partial Least Squares.</a> NeuroImage. 3, 143-157 (1996).</li><li>McIntosh, A., Gonzalez-Lima, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Network+interactions+among+limbic+cortices,+basal+forebrain+and+cerebellum+differentiate+a+tone+conditioned+as+a+Pavlovian+excitor+or+inhibitor:+fluorodeoxyglucose+and+covariance+structural+modeling.">Network interactions among limbic cortices, basal forebrain and cerebellum differentiate a tone conditioned as a Pavlovian excitor or inhibitor: fluorodeoxyglucose and covariance structural modeling.</a> J. Neurophysiol. 72, 1717-1733 (1994).</li><li>McIntosh, A., Lobaugh, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Partial+least+squares+analysis+of+neuroimaging+data:+applications+and+advances.">Partial least squares analysis of neuroimaging data: applications and advances.</a> Neuroimage. 23, 250-263 (2004).</li><li>Frackowiack, R. S. J., Frith, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Human Brain Function. , (2003).</li></ol>

No conflicts of interest declared.

We predict that those youths who show the greatest impact on brain white matter will show the greatest reorganization of brain activity, and the longest behavioural and neural recovery periods. This research will provide a better understanding of pediatric post-concussion events and have a significant impact on medical care, as it will allow us to establish a recovery protocol based on research evidence that is specific to children and youth. Such a protocol can then be translated to stakeholders, including parents, co...

<table border="1">
 <tbody>
 <tr>
 <td>Name</td>
 <td>Company</td>
 <td>Comments</td>
 </tr>
 <tr>
 <td>AccuGait Portable Gait and Balance Platform 
 (Balance Assessment)</td>
 <td>AMTI</td>
 <td><a href="http://www.amti.biz/">www.amti.biz</a></td>
 </tr>
 <tr>
 <td>NetForce Balance Data Acquisition Software</td>
 <td>AMTI</td>
 <td><a href="http://www.amti.biz/">www.amti.biz</a></td>
 </tr>
 <tr>
 <td>Visual Conflict Dome</td>
 <td>&nbsp;</td>
 <td>Fabricated by researchers; modeled after: Lovell MR, Collins MW. Neuropsychological assessment of the college 					football player. J Head Trauma Rehabil. 1998;13(2):9-26.</td>
 </tr>
 <tr>
 <td>Airex Balance Pad</td>
 <td>Airex</td>
 <td><a href="http://www.bebalanced.net/">www.bebalanced.net</a></td>
 </tr>
 <tr>
 <td>Smedlay's Dynamometer, 100 kg(Grip Strength)</td>
 <td>TTM, Tokyo</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Grooved Pegboard Test</td>
 <td>Lafayette Instrument Company</td>
 <td><a href="http://www.lafayetteinstrument.com/">www.lafayetteinstrument.com</a></td>
 </tr>
 <tr>
 <td>Axon Jump Mat</td>
 <td>Vacumed</td>
 <td><a href="http://www.vacumed.com/">www.vacumed.com</a></td>
 </tr>
 <tr>
 <td>Strength Bar</td>
 <td>&nbsp;</td>
 <td>Fabricated by researchers: 
 <ul>
 <li>31" titanium lacrosse handle</li>
 <li>Two 40" utility chains</li>
 <li>24" x 26" plywood platform</li>
 <li>Two dock ring fasteners</li>
 <li>Two U-bolts (1" width)</li>
 </ul></td>
 </tr>
 <tr>
 <td>Head Impact Telemetry (HIT) System</td>
 <td>Simbex</td>
 <td><a href="http://www.simbex.com/">www.simbex.com</a></td>
 </tr>
 <tr>
 <td>Post-Concussion Symptoms Scale Revised (PCS-R)</td>
 <td>&nbsp;</td>
 <td>Adapted from: 
 Lovell MR, Collins MW. Neuropsychological assessment of the college football player. J Head Trauma Rehabil. 1998;13(2):9-26.</td>
 </tr>
 <tr>
 <td>GE Discovery&trade; MR750 3.0T MRI Scanner</td>
 <td>GE</td>
 <td><a href="http://www.gehealthcare.com/">www.gehealthcare.com</a></td>
 </tr>
 <tr>
 <td>GE 8 channel head coil</td>
 <td>GE</td>
 <td><a href="http://www.gehealthcare.com/">www.gehealthcare.com</a></td>
 </tr>
 <tr>
 <td>Lumitouch Reply System</td>
 <td>Lightwave Medical Industries</td>
 <td>Vancouver, BC 1-(604)-875-4529</td>
 </tr>
 <tr>
 <td>Back projection screen (for presenting fMRI stimuli)</td>
 <td>Unknown</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Disposable foam ear plugs</td>
 <td>PAR Inc.</td>
 <td><a href="http://www.parinc.com/">www.parinc.com</a></td>
 </tr>
 <tr>
 <td>Neuropsychological Tests</td>
 <td>Pearson Assessments</td>
 <td><a href="http://www.pearsonassessments.com/">www.pearsonassessments.com</a></td>
 </tr>
 </tbody>
</table>

an investigation of the effects of sports-related concussion in youth using functional magnetic resonance imaging and the head impact telemetry system

One of the most commonly reported injuries in children who participate in sports is concussion or mild traumatic brain injury (mTBI)1. Children and youth involved in organized sports such as competitive hockey are nearly six times more likely to suffer a severe concussion compared to children involved in other leisure physical activities2. While the most common cognitive sequelae of mTBI appear similar for children and adults, the recovery profile and breadth of consequences in children remains largely unknown2, as does the influence of pre-injury characteristics (e.g. gender) and injury details (e.g. magnitude and direction of impact) on long-term outcomes. Competitive sports, such as hockey, allow the rare opportunity to utilize a pre-post design to obtain pre-injury data before concussion occurs on youth characteristics and functioning and to relate this to outcome following injury. Our primary goals are to refine pediatric concussion diagnosis and management based on research evidence that is specific to children and youth. To do this we use new, multi-modal and integrative approaches that will:
 1.Evaluate the immediate effects of head trauma in youth 
2.Monitor the resolution of post-concussion symptoms (PCS) and cognitive performance during recovery 
3.Utilize new methods to verify brain injury and recovery
To achieve our goals, we have implemented the Head Impact Telemetry (HIT) System. (Simbex; Lebanon, NH, USA). This system equips commercially available Easton S9 hockey helmets (Easton-Bell Sports; Van Nuys, CA, USA) with single-axis accelerometers designed to measure real-time head accelerations during contact sport participation 3 - 5. By using telemetric technology, the magnitude of acceleration and location of all head impacts during sport participation can be objectively detected and recorded. We also use functional magnetic resonance imaging (fMRI) to localize and assess changes in neural activity specifically in the medial temporal and frontal lobes during the performance of cognitive tasks, since those are the cerebral regions most sensitive to concussive head injury 6. Finally, we are acquiring structural imaging data sensitive to damage in brain white matter.

Watch this Scientific Journal Video about An Investigation of the Effects of Sports-related Concussion in Youth Using Functional Magnetic Resonance Imaging and the Head Impact Telemetry System at JoVE

An Investigation of the Effects of Sports-related Concussion in Youth Using Functional Magnetic Resonance Imaging and the Head Impact Telemetry System

This article provides an overview of a multi-modal approach to mild traumatic brain injury diagnosis and recovery in youth. This approach combines neuropsychological testing with functional magnetic resonance imaging and the Head Impact Telemetry System to monitor the relationship between head impacts and brain activity during cognitive testing.

One of the most commonly reported injuries in children who participate in sports is concussion or mild traumatic brain injury (mTBI)1. Children and youth ...

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Research

JoVE Journal

Medicine

15.7K 次观看.  University of Toronto. 本文提供了一个多模态的方法，轻度创伤性脑损伤的诊断和恢复在青年的概述。这种方法结合了神经心理测试，功能磁共振成像和头部撞击遥测系统，以监测在认知测试头的影响和大脑活动之间的关系。

视频: An Investigation of the Effects of Sports-related Concussion in Youth Using Functional Magnetic Resonance Imaging and the Head Impact Telemetry System

Magnetic Resonance Derived Myocardial Strain Assessment Using Feature Tracking

Purpose: An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF. Current technologies for CMR are time consuming and difficult to implement in clinical practice. Feature tracking is a technology that can lead to more automization and robustness of quantitative analysis of medical images with less time consumption than comparable methods.
Methods: An automatic or manual input in a single phase serves as an initialization from which the system starts to track the displacement of individual patterns representing anatomical structures over time. The specialty of this method is that the images do not need to be manipulated in any way beforehand like e.g. tagging of CMR images.
Results: The method is very well suited for tracking muscular tissue and with this allowing quantitative elaboration of myocardium and also blood flow.
Conclusions: This new method offers a robust and time saving procedure to quantify myocardial tissue and blood with displacement, velocity and deformation parameters on regular sequences of CMR imaging. It therefore can be implemented in clinical practice.

An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF.

Purpose: An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that ...

Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases

Diffusion tensor imaging (DTI) techniques provide information on the microstructural processes of the cerebral white matter (WM) in vivo. The present applications are designed to investigate differences of WM involvement patterns in different brain diseases, especially neurodegenerative disorders, by use of different DTI analyses in comparison with matched controls. 	
DTI data analysis is performed in a variate fashion, i.e. voxelwise comparison of regional diffusion direction-based metrics such as fractional anisotropy (FA), together with fiber tracking (FT) accompanied by tractwise fractional anisotropy statistics (TFAS) at the group level in order to identify differences in FA along WM structures, aiming at the definition of regional patterns of WM alterations at the group level. Transformation into a stereotaxic standard space is a prerequisite for group studies and requires thorough data processing to preserve directional inter-dependencies. The present applications show optimized technical approaches for this preservation of quantitative and directional information during spatial normalization in data analyses at the group level. On this basis, FT techniques can be applied to group averaged data in order to quantify metrics information as defined by FT. Additionally, application of DTI methods, i.e. differences in FA-maps after stereotaxic alignment, in a longitudinal analysis at an individual subject basis reveal information about the progression of neurological disorders. Further quality improvement of DTI based results can be obtained during preprocessing by application of a controlled elimination of gradient directions with high noise levels.	
In summary, DTI is used to define a distinct WM pathoanatomy of different brain diseases by the combination of whole brain-based and tract-based DTI analysis.

Diffusion tensor imaging (DTI) basically serves as an MRI-based tool to identify in vivo the microstructure of the brain and pathological processes due to neurological disorders within the cerebral white matter. DTI-based analyses allow for application to brain diseases both at the group level and in single subject data.

Diffusion tensor imaging (DTI) techniques provide information on the microstructural processes of the cerebral white matter (WM) in vivo. The present ...

Using Multi-fluorinated Bile Acids and In Vivo Magnetic Resonance Imaging to Measure Bile Acid Transport

Along with their traditional role as detergents that facilitate fat absorption, emerging literature indicates that bile acids are potent signaling molecules that affect multiple organs; they modulate gut motility and hormone production, and alter vascular tone, glucose metabolism, lipid metabolism, and energy utilization. Changes in fecal bile acids may alter the gut microbiome and promote colon pathology including cholerrheic diarrhea and colon cancer. Key regulators of fecal bile acid composition are the small intestinal Apical Sodium-dependent Bile Acid Transporter (ASBT) and fibroblast growth factor-19 (FGF19). Reduced expression and function of ASBT decreases intestinal bile acid up-take. Moreover, in vitro data suggest that some FDA-approved drugs inhibit ASBT function. Deficient FGF19 release increases hepatic bile acid synthesis and release into the intestines to levels that overwhelm ASBT. Either ASBT dysfunction or FGF19 deficiency increases fecal bile acids and may cause chronic diarrhea and promote colon neoplasia. Regrettably, tools to measure bile acid malabsorption and the actions of drugs on bile acid transport in vivo are limited. To understand the complex actions of bile acids, techniques are required that permit simultaneous monitoring of bile acids in the gut and metabolic tissues. This led us to conceive an innovative method to measure bile acid transport in live animals using a combination of proton (1H) and fluorine (19F) magnetic resonance imaging (MRI). Novel tracers for fluorine (19F)-based live animal MRI were created and tested, both in vitro and in vivo. Strengths of this approach include the lack of exposure to ionizing radiation and translational potential for clinical research and practice.

Using Multi-fluorinated Bile Acids and In Vivo Magnetic Resonance Imaging to Measure Bile Acid Transport

Tools to diagnose bile acid malabsorption and measure bile acid transport in vivo are limited. An innovative approach in live animals is described that utilizes combined proton (1H) plus fluorine (19F) magnetic resonance imaging; this novel methodology has translational potential to screen for bile acid malabsorption in clinical practice.

Along with their traditional role as detergents that facilitate fat absorption, emerging literature indicates that bile acids are potent signaling ...

Phosphorus-31 Magnetic Resonance Spectroscopy: A Tool for Measuring In Vivo Mitochondrial Oxidative Phosphorylation Capacity in Human Skeletal Muscle

Skeletal muscle mitochondrial oxidative phosphorylation (OXPHOS) capacity, which is critically important in health and disease, can be measured in vivo and noninvasively in humans via phosphorus-31 magnetic resonance spectroscopy (31PMRS). However, the approach has not been widely adopted in translational and clinical research, with variations in methodology and limited guidance from the literature. Increased optimization, standardization, and dissemination of methods for in vivo 31PMRS would facilitate the development of targeted therapies to improve OXPHOS capacity and could ultimately favorably impact cardiovascular health. 31PMRS produces a noninvasive, in vivo measure of OXPHOS capacity in human skeletal muscle, as opposed to alternative measures obtained from explanted and potentially altered mitochondria via muscle biopsy. It relies upon only modest additional instrumentation beyond what is already in place on magnetic resonance scanners available for clinical and translational research at most institutions. In this work, we outline a method to measure in vivo skeletal muscle OXPHOS. The technique is demonstrated using a 1.5 Tesla whole-body MR scanner equipped with the suitable hardware and software for 31PMRS, and we explain a simple and robust protocol for in-magnet resistive exercise to rapidly fatigue the quadriceps muscle. Reproducibility and feasibility are demonstrated in volunteers as well as subjects over a wide range of functional capacities.

Phosphorus-31 Magnetic Resonance Spectroscopy: A Tool for Measuring In Vivo Mitochondrial Oxidative Phosphorylation Capacity in Human Skeletal Muscle

This work demonstrates the feasibility of an in vivo phosphorus-31 magnetic resonance spectroscopy (31PMRS) technique to quantify mitochondrial oxidative phosphorylation (OXPHOS) capacity in human skeletal muscle.

Skeletal muscle mitochondrial oxidative phosphorylation (OXPHOS) capacity, which is critically important in health and disease, can be measured in vivo ...

Cardiac Magnetic Resonance Imaging at 7 Tesla

CMR at an ultra-high field (magnetic field strength B0&#160;&#8805; 7 Tesla) benefits from the signal-to-noise ratio (SNR) advantage inherent at higher magnetic field strengths and potentially provides improved signal contrast and spatial resolution. While promising results have been achieved, ultra-high field CMR is challenging due to energy deposition constraints and physical phenomena such as transmission field non-uniformities and magnetic field inhomogeneities. In addition, the magneto-hydrodynamic effect renders the synchronization of the data acquisition with the cardiac motion difficult. The challenges are currently addressed by explorations into novel magnetic resonance technology. If all impediments can be overcome, ultra-high field CMR may generate new opportunities for functional CMR, myocardial tissue characterization, microstructure imaging or metabolic imaging. Recognizing this potential, we show that multi-channel radio frequency (RF) coil technology tailored for CMR at 7 Tesla together with higher order B0 shimming and a backup signal for cardiac triggering facilitates high fidelity functional CMR. With the proposed setup, cardiac chamber quantification can be accomplished in examination times similar to those achieved at lower field strengths. To share this experience and to support the dissemination of this expertise, this work describes our setup and protocol tailored for functional CMR at 7 Tesla.

The sensitivity gain inherent to ultrahigh field magnetic resonance holds promise for high spatial resolution imaging of the heart. Here, we describe a protocol customized for functional cardiovascular magnetic resonance (CMR) at 7 Tesla using an advanced multi-channel radio-frequency coil, magnetic field shimming and a triggering concept.

CMR at an ultra-high field (magnetic field strength B0&#160;&#8805; 7 Tesla) benefits from the signal-to-noise ratio (SNR) advantage inherent at higher ...

In Vivo Morphometric Analysis of Human Cranial Nerves Using Magnetic Resonance Imaging in Meni&#232;re's Disease Ears and Normal Hearing Ears

Analysis of neural structures in Meni&#232;re's Disease (MD) is of importance, since a loss of such structures has previously been proposed for this patient group but has yet to be confirmed. This protocol describes a method of in vivo evaluation of neural changes especially well suitable for cranial nerve analysis using magnetic resonance imaging (MRI). MD-patients and normal hearing persons were examined in a 3-T MR-scanner using a scan protocol including strongly T2-weighted 3D gradient-echo-sequence (3D-CISS). In the patient group, MD was additionally confirmed using MRI-based assessment of endolymphatic hydrops. Morphometric analysis was performed using a freeware DICOM viewer. Evaluation of cranial nerves included measurements of cross-sectional areas (CSAs) of the nerves at different levels as well as orthogonal diametric measurements.

&lt;em&gt;In Vivo&lt;/em&gt; Morphometric Analysis of Human Cranial Nerves Using Magnetic Resonance Imaging in Meni&amp;#232;re&#039;s Disease Ears and Normal Hearing Ears

To evaluate morphological changes of cranial nerves such as loss of neural structures or swelling of cranial nerves in Meni&#232;re&#39;s Disease (MD) or in healthy persons in vivo, a protocol of evaluation has been developed using magnetic resonance imaging (MRI). Additional MRI-based confirmation of MD was performed.

Analysis of neural structures in Meni&#232;re's Disease (MD) is of importance, since a loss of such structures has previously been proposed for this ...

Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery

Phase contrast magnetic resonance imaging (PC-MRI) is a noninvasive approach that can quantify flow-related parameters such as blood flow. Previous studies have shown that abnormal blood flow may be associated with systemic vascular risk. Thus, PC-MRI can facilitate the translation of data obtained from animal models of cardiovascular diseases to pertinent clinical investigations. In this report, we describe the procedure for measuring blood flow in the common carotid artery (CCA) of rats using cine-gated PC-MRI and discuss relevant analysis methods. This procedure can be performed in a live, anesthetized animal and does not require euthanasia after the procedure. The proposed scanning parameters yield repeatable measurements for blood flow, indicating excellent reproducibility of the results. The PC-MRI procedure described in this article can be used for pharmacological testing, pathophysiological assessment, and cerebral hemodynamics evaluation.

The overall goal of this procedure is to measure the blood flow in the rat common carotid artery by using noninvasive phase contrast magnetic resonance imaging.

Phase contrast magnetic resonance imaging (PC-MRI) is a noninvasive approach that can quantify flow-related parameters such as blood flow. Previous ...

Autonomic Function Following Concussion in Youth Athletes: An Exploration of Heart Rate Variability Using 24-hour Recording Methodology

Participation in organized sports makes a significant contribution to youth development, but places youth at a higher risk for sustaining a concussion. To date, return-to-activity decision-making has been anchored in the monitoring of self-reported concussion symptoms and neurocognitive testing. However, multi-modal assessments that corroborate objective physiological measures with traditional subjective symptom reporting are needed and can be valuable. Heart rate variability (HRV) is a non-invasive physiological indicator of the autonomic nervous system, capturing the reciprocal interplay between the sympathetic and parasympathetic nervous systems. There is a dearth of literature exploring the effect of concussion on HRV in youth athletes, and developmental differences preclude the application of adult findings to a pediatric population. Further, the current state of HRV methodology has primarily included short-term (5-15 min) recordings, by using resting state or short-term physical exertion testing to elucidate changes following concussion. The novelty in utilizing a 24 h&#160;recording methodology is that it has the potential to capture natural variation in autonomic function, directly related to the activities a youth athlete performs on a regular basis. Within a prospective, longitudinal research setting, this novel approach to quantifying autonomic function can provide important information regarding the recovery trajectory, alongside traditional self-report symptom measures. Our objectives regarding a 24 h recording methodology were to (1) evaluate the physiological effects of a concussion in youth athletes, and (2) describe the trajectory of physiological change, while considering the resolution of self-reported post-concussion symptoms. To achieve these objectives, non-invasive sensor technology was implemented. The raw beat-to-beat time intervals captured can be transformed to derive time domain and frequency domain measures, which reflect an individual&#39;s ability to adapt and be flexible to their ever-changing environment. By using non-invasive heart rate technology, autonomic function can be quantified outside of a traditional controlled research setting.

We demonstrate a 24 h heart rate recording methodology to evaluate the influence of concussion across the recovery trajectory in youth athletes, within an ecologically valid context.

Participation in organized sports makes a significant contribution to youth development, but places youth at a higher risk for sustaining a concussion. To ...

Cardiac Magnetic Resonance for the Evaluation of Suspected Cardiac Thrombus: Conventional and Emerging Techniques

We present the conventional cardiac magnetic resonance (CMR) protocol for evaluating a suspected thrombus and highlight emerging techniques.&#160;The appearance of a mass on certain magnetic resonance (MR) sequences can help differentiate a thrombus from competing diagnoses such as a tumor. T1 and T2 signal characteristics of a thrombus are related to the evolution of hemoglobin properties. A thrombus typically does not enhance following contrast administration, which also helps differentiation from a tumor. We also highlight the emerging role of T1 mapping in the evaluation of a thrombus, which can add another level of support in diagnosis. Prior to any CMR exam, patient screening and interviews are critical to ensure safety and to optimize patient comfort. Effective communication during the exam between the technologist and the patient promotes proper breath holding technique and higher quality images. Volumetric post processing and structured reporting are helpful to ensure that the radiologist answers the ordering services&#39; question and communicates these results effectively. Optimal pre-MR safety evaluation, CMR exam execution, and post exam processing and reporting allow for delivery of high quality radiological service in the evaluation of a suspected cardiac thrombus.

The goal of this article is to describe how cardiac magnetic resonance can be used for the evaluation and diagnosis of a suspected cardiac thrombus. The method presented will describe data acquisition as well as the pre-procedure and post-procedure protocol.

We present the conventional cardiac magnetic resonance (CMR) protocol for evaluating a suspected thrombus and highlight emerging techniques.&#160;The ...

Quantitative Mapping of Specific Ventilation in the Human Lung using Proton Magnetic Resonance Imaging and Oxygen as a Contrast Agent

Specific ventilation imaging (SVI) is a functional magnetic resonance imaging technique capable of quantifying specific ventilation &#8213; the ratio of the fresh gas entering a lung region divided by the region&#8217;s end-expiratory volume &#8213; in the human lung, using only inhaled oxygen as a contrast agent. Regional quantification of specific ventilation has the potential to help identify areas of pathologic lung function. Oxygen in solution in tissue shortens the tissue&#8217;s longitudinal relaxation time (T1), and thus a change in tissue oxygenation can be detected as a change in T1-weighted signal with an inversion recovery acquired image. Following an abrupt change between two concentrations of inspired oxygen, the rate at which lung tissue within a voxel equilibrates to a new steady-state reflects the rate at which resident gas is being replaced by inhaled gas. This rate is determined by specific ventilation. To elicit this sudden change in oxygenation, subjects alternately breathe 20-breath blocks of air (21% oxygen) and 100% oxygen while in the MRI scanner. A stepwise change in inspired oxygen fraction is achieved through use of a custom three-dimensional (3D)-printed flow bypass system with a manual switch during a short end-expiratory breath hold. To detect the corresponding change in T1, a global inversion pulse followed by a single shot fast spin echo sequence was used to acquire two-dimensional T1-weighted images in a 1.5&#160;T MRI scanner, using an eight-element torso coil. Both single slice and multi-slice imaging are possible, with slightly different imaging parameters. Quantification of specific ventilation is achieved by correlating the time-course of signal intensity for each lung voxel with a library of simulated responses to the air/oxygen stimulus. SVI estimations of specific ventilation heterogeneity have been validated against multiple breath washout and proved to accurately determine the heterogeneity of the specific ventilation distribution.

Specific ventilation imaging is a functional magnetic resonance imaging technique that allows for quantification of regional specific ventilation in the human lung, using inhaled oxygen as a contrast agent. Here, we present a protocol to collect and analyze specific ventilation imaging data.

Specific ventilation imaging (SVI) is a functional magnetic resonance imaging technique capable of quantifying specific ventilation &#8213; the ratio of ...