scholarly journals Heart rate monitoring in ultra-high-field MRI using frequency information obtained from video signals of the human skin compared to electrocardiography and pulse oximetry

2015 ◽  
Vol 1 (1) ◽  
pp. 69-72 ◽  
Author(s):  
Nicolai Spicher ◽  
Stefan Maderwald ◽  
Mark E. Ladd ◽  
Markus Kukuk
Keyword(s):  
Heart Rate ◽  
Pulse Oximetry ◽  
Human Skin ◽  
High Field ◽  
7 Tesla ◽  
Contactless Method ◽  
Heart Rate Monitoring ◽  
Ultra High Field ◽  
Heart Rates ◽  
Patient Table

AbstractVideos of the human skin contain subtle color variations associated with the blood volume pulse. This remote photoplethysmography signal can be used for heart rate monitoring and represents an alternative to signals obtained from contact-based hardware. We developed an algorithm that estimates the heart rate in real-time from photoplethysmography signals and evaluate its performance in the context of ultra-high-field magnetic resonance imaging. We compare its accuracy to heart rate values estimated from electrocardiography and finger pulse oximetry triggers, obtained from MR vendor-provided hardware. For eight subjects, two experiments are conducted with the patient table outside and inside a 7 Tesla scanner. During both 5 min setups, heart rates from the algorithm and contact-based methods are stored. Their comparison suggests technical feasibility of the contactless method but that it is inferior in accuracy compared to contact-based hardware and that low heart rates (≤50 beats per minute) and adequate illumination are major challenges for practical feasibility.

S8. Increased Locus Coeruleus Volume in Humans With Pathological Anxiety: An Ultra-High Field 7-Tesla MRI Study

2019 ◽  
Vol 85 (10) ◽  
pp. S299-S300
Author(s):  
Laurel Morris ◽  
Aaron Tan ◽  
Derek Smith ◽  
Mora Grehl ◽  
Kuang-Han Huang ◽  
...  
Keyword(s):  
Locus Coeruleus ◽  
High Field ◽  
7 Tesla ◽  
Ultra High Field ◽  
7 Tesla Mri ◽  
Mri Study ◽  
Pathological Anxiety

scholarly journals P.063 Stereotactic targeting of hippocampal substructures using ultra-high field magnetic resonance imaging: Feasibility study in patients with epilepsy

2018 ◽  
Vol 45 (s2) ◽  
pp. S32-S33
Author(s):  
JC Lau ◽  
J DeKraker ◽  
KW MacDougall ◽  
H Joswig ◽  
AG Parrent ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Dentate Gyrus ◽  
High Field ◽  
Longitudinal Axis ◽  
The Body ◽  
7 Tesla ◽  
Resonance Imaging ◽  
Ultra High Field

Background: The hippocampus can be divided longitudinally into the head, body, and tail; and unfolded medial-to-laterally into the subiculum, cornu ammonis (CA) sectors, and the dentate gyrus. Ultra-high field (≥ 7 Tesla; 7T) magnetic resonance imaging (MRI) enables submillimetric visualization of these hippocampal substructures which could be valuable for surgical targeting. Here, we assess the feasibility of using 7T MRI in conjunction with a novel computational unfolding method for image-based stereotactic targeting of hippocampal substructures. Methods: 53 patients with drug-resistant epilepsy were identified undergoing first-time implantation of the hippocampus. An image processing pipeline was created for computationally transforming post-operative electrode contact locations into our hippocampal coordinate system. Results: Of 178 implanted hippocampal electrodes (88 left; 49.4%), 25 (14.0%) were predominantly in the subiculum, 85 (47.8%) were in CA1, 23 (12.9%) were in CA2, 18 (10.1%) were in CA3/CA4, and 27 (15.2%) were in dentate gyrus. Along the longitudinal axis, hippocampal electrodes were most commonly implanted in the body (92; 51.7%) followed by the head (86; 48.3%). Conclusions: 7T MRI enables high-resolution anatomical imaging on the submillimeter scale in in vivo subjects. Here, we demonstrate the utility of 7T imaging for identifying the relative location of SEEG electrode implantations within hippocampal substructures for the invasive investigation of epilepsy.

scholarly journals The Amsterdam Ultra-high field adult lifespan database (AHEAD): A freely available multimodal 7 Tesla submillimeter magnetic resonance imaging database

NeuroImage ◽  
2020 ◽  
Vol 221 ◽  
pp. 117200 ◽  
Author(s):  
Anneke Alkemade ◽  
Martijn J Mulder ◽  
Josephine M Groot ◽  
Bethany R Isaacs ◽  
Nikita van Berendonk ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Field ◽  
7 Tesla ◽  
Resonance Imaging ◽  
Ultra High Field ◽  
Adult Lifespan

Focal multiple sclerosis lesions abound in ‘normal appearing white matter’

2011 ◽  
Vol 17 (11) ◽  
pp. 1313-1323 ◽  
Author(s):  
Niraj Mistry ◽  
Emma C Tallantyre ◽  
Jennifer E Dixon ◽  
Nicolas Galazis ◽  
Tim Jaspan ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
High Field ◽  
White Matter Lesions ◽  
7 Tesla ◽  
Ultra High Field ◽  
Rapid Acquisition ◽  
Normal Appearing White Matter ◽  
Mri Scans ◽  
Image Type

Background: The ‘normal appearing white matter’ (NAWM) in multiple sclerosis (MS) is known to be abnormal using quantitative magnetic resonance (MR) techniques. The aetiology of the changes in NAWM remains debatable. Objective: To investigate whether high-field and ultra high-field T1-weighted magnetization prepared rapid acquisition gradient echo (MPRAGE) MRI enables detection of MS white matter lesions in areas defined as NAWM using high-field T2-weighted fluid attenuation inversion recovery (FLAIR) MRI; that is, to ascertain whether undetected lesions are likely contributors to the burden of abnormality in similarly defined NAWM. Methods: Fourteen MS patients underwent MRI scans using 3T FLAIR and MPRAGE and 7 Tesla (7T) MPRAGE sequences. Independent observers identified lesions on 3T FLAIR and (7T and 3T) MPRAGE images. The detection of every individual lesion was then compared for each image type. Results: We identified a total of 812 white matter lesions on 3T FLAIR. Using 3T MPRAGE, 186 additional lesions were detected that were not detected using 3T FLAIR. Using 7T MPRAGE, 231 additional lesions were detected that were not detected using 3T FLAIR. Conclusions: MRI with 3T and 7T MPRAGE enables detection of MS lesions in areas defined as NAWM using 3T FLAIR. Focal MS lesions contribute to the abnormalities known to exist in the NAWM.

scholarly journals Functional activation changes at ultra-high field related to upper and lower limb impairments in multiple sclerosis

2020 ◽  
Author(s):  
Myrte Strik ◽  
Camille Shanahan ◽  
Anneke Van der Walt ◽  
Frederique Boonstra ◽  
Rebecca Glarin ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Lower Limb ◽  
High Field ◽  
Premotor Cortex ◽  
Network Activity ◽  
7 Tesla ◽  
Ultra High Field ◽  
Sensorimotor Network ◽  
Force Matching ◽  
Early Stages

Upper and lower limb impairments are common in people with multiple sclerosis (pwMS), yet difficult to clinically identify in early stages of disease progression. Tasks involving complex motor control can potentially reveal more subtle deficits in early stages, and can be performed during functional MRI acquisition, to investigate underlying neural mechanisms, providing markers for early motor progression. We investigated brain activation during visually-guided force-matching of hand or foot in 28 minimally disabled pwMS and 17 healthy controls (HC) using ultra-high field 7-Tesla fMRI, allowing us to visualise sensorimotor network activity in high detail. Task activations and performance (tracking lag and error) were compared between groups, and correlations were performed. PwMS showed delayed (+124 s, p=0.002) and more erroneous (+0.15 N, p=0.001) lower limb tracking, together with higher primary motor and premotor cortex activation, and lower cerebellar activation compared to HC. No differences were seen in upper limb performance or activation. Functional activation levels of cerebellar, visual and motor areas correlated with task performance. These results demonstrate that ultra-high field fMRI during complex hand and foot tracking can identify subtle impairments in movement and brain activity, and differentiates upper and lower limb impairments in minimally disabled pwMS.

scholarly journals Real-Time Cardiac Beat Detection and Heart Rate Monitoring from Combined Seismocardiography and Gyrocardiography

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3472 ◽  
Author(s):  
D’Mello ◽  
Skoric ◽  
Xu ◽  
Roche ◽  
Lortie ◽  
...  
Keyword(s):  
Heart Rate ◽  
Real Time ◽  
Time Algorithm ◽  
Cardiac Monitoring ◽  
Computational Time ◽  
Heart Rate Monitoring ◽  
Heart Rates ◽  
Non Invasive ◽  
Beat Detection ◽  
Speed Accuracy

Cardiography is an indispensable element of health care. However, the accessibility of at-home cardiac monitoring is limited by device complexity, accuracy, and cost. We have developed a real-time algorithm for heart rate monitoring and beat detection implemented in a custom-built, affordable system. These measurements were processed from seismocardiography (SCG) and gyrocardiography (GCG) signals recorded at the sternum, with concurrent electrocardiography (ECG) used as a reference. Our system demonstrated the feasibility of non-invasive electro-mechanical cardiac monitoring on supine, stationary subjects at a cost of $100, and with the SCG–GCG and ECG algorithms decoupled as standalone measurements. Testing was performed on 25 subjects in the supine position when relaxed, and when recovering from physical exercise, to record 23,984 cardiac cycles at heart rates in the range of 36–140 bpm. The correlation between the two measurements had r2 coefficients of 0.9783 and 0.9982 for normal (averaged) and instantaneous (beat identification) heart rates, respectively. At a sampling frequency of 250 Hz, the average computational time required was 0.088 s per measurement cycle, indicating the maximum refresh rate. A combined SCG and GCG measurement was found to improve accuracy due to fundamentally different noise rejection criteria in the mutually orthogonal signals. The speed, accuracy, and simplicity of our system validated its potential as a real-time, non-invasive, and affordable solution for outpatient cardiac monitoring in situations with negligible motion artifact.

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