SNR and Total Acquisition Time Analysis of Multi-Echo FLASH Pulse Sequence for Current Density Imaging

2021 ◽  
pp. 107098
Author(s):  
Mehdi Sadighi ◽  
Mert Şişman ◽  
B. Murat Eyüboğlu
Keyword(s):  
Current Density ◽  
Pulse Sequence ◽  
Acquisition Time ◽  
Time Analysis ◽  
Total Acquisition Time ◽  
Current Density Imaging

scholarly journals Optimization of spectral-domain optical coherence tomography with a supercontinuum source for in vivo motion detection of low reflective outer hair cells in guinea pig cochleae

2021 ◽  
Author(s):  
Fumiaki Nin ◽  
Samuel Choi ◽  
Takeru Ota ◽  
Zhang Qi ◽  
Hiroshi Hibino
Keyword(s):  
Optical Coherence Tomography ◽  
High Resolution ◽  
Guinea Pig ◽  
Hair Cells ◽  
Sensory Epithelium ◽  
Outer Hair Cells ◽  
Acquisition Time ◽  
Total Acquisition Time ◽  
Sd Oct

AbstractSound evokes sub-nanoscale vibration within the sensory epithelium. The epithelium contains not only immotile cells but also contractile outer hair cells (OHCs) that actively shrink and elongate synchronously with the sound. However, the in vivo motion of OHCs has remained undetermined. The aim of this work is to perform high-resolution and -accuracy vibrometry in live guinea pigs with an SC-introduced spectral-domain optical coherence tomography system (SD-OCT). In this study, to reveal the effective contribution of SC source in the recording of the low reflective materials with the short total acquisition time, we compare the performances of the SC-introduced SD-OCT (SCSD-OCT) to that of the conventional SD-OCT. As inanimate comparison objects, we record a mirror, a piezo actuator, and glass windows. For the measurements in biological materials, we use in/ex vivo guinea pig cochleae. Our study achieved the optimization of a SD-OCT system for high-resolution in vivo vibrometry in the cochlear sensory epithelium, termed the organ of Corti, in mammalian cochlea. By introducing a supercontinuum (SC) light source and reducing the total acquisition time, we improve the axial resolution and overcome the difficulty in recording the low reflective material in the presence of biological noise. The high power of the SC source enables the system to achieve a spatial resolution of 1.72 ± 0.00 μm on a mirror and reducing the total acquisition time contributes to the high spatial accuracy of sub-nanoscale vibrometry. Our findings reveal the vibrations at the apical/basal region of OHCs and the extracellular matrix, basilar membrane.

T2-weighted spin-echo pulse sequence with variable repetition and echo times for reduction of MR image acquisition time.

Radiology ◽  
1991 ◽  
Vol 180 (2) ◽  
pp. 551-556 ◽  
Author(s):  
R K Butts ◽  
F Farzaneh ◽  
S J Riederer ◽  
J N Rydberg ◽  
R C Grimm
Keyword(s):  
Pulse Sequence ◽  
Spin Echo ◽  
Image Acquisition ◽  
Acquisition Time ◽  
Mr Image ◽  
Image Acquisition Time ◽  
Echo Pulse

scholarly journals Simulation models of current density imaging in studying cardiac states

2021 ◽  
Author(s):  
Mohammadali Beheshti
Keyword(s):  
Cardiac Function ◽  
Electrical Activity ◽  
Current Density ◽  
Diffusion Tensor ◽  
Model Simulation ◽  
Correlation Coefficients ◽  
Biological Tissues ◽  
Density Maps ◽  
Current Density Imaging ◽  
Rms Error

Electro-mechanical disorders in cardiac function result in arrhythmias. Due to the non-stationary nature of these arrhythmias and, owing to lethality associated with certain type of arrhythmias, they are challenging to study. Most of the existing studies are limited in that they extract electrical activity from surface intracardiac electrical activity, either through the use of electrical or optical mapping. One way of studying current pathways inside and through biological tissues is by using Magnetic Resonance Imaging (MRI) based Low Frequency Current Density Imaging (LFCDI). For the first time CDI was used to study ex-vivo beating hearts in different cardiac states. It should be said that; this approach involves heavy logistical and procedural complexity, hence, it would be beneficial to adapt existing electrophysiological computer models to investigate and simulate current density maps specific to studying cardiac function. In achieving this, the proposed work presents an approach to model the current density maps in 3D and study the current distributions in different electrophysiological states of the heart. The structural and fiber orientation of the heart used in this study were extracted using MRI-based Diffusion Tensor Imaging. The monodomain and bidomain Aliev-Panfilov electrophysiological models were used for CDI modeling, and the results indicate that different states were distinguishable using range and correlation of simulated current density maps. The obtained results through modeling were corroborated with actual experimental CDI data from porcine hearts. Individually and comparatively, the experimental and simulation results for various states have the same trend in terms of variations (trend correlation coefficients ≥ 0.98) and state correlations (trend correlation coefficients ≥ 0.89). The results also show that the root mean square (RMS) error in average range ratios between bidomain CDI model results and real CDI data is 0.1972 and the RMS error in state correlations between bidomain CDI model results and real CDI data is 0.2833. These results indicate, as expected, the proposed bidomain model simulation of CDI corroborates well with experimental data and can serve as a valuable tool for studying lethal cardiac arrhythmias under different simulation conditions that are otherwise not possible or difficult in a real-world experimental setup.

scholarly journals Simulation models of current density imaging in studying cardiac states

2021 ◽  
Author(s):  
Mohammadali Beheshti
Keyword(s):  
Cardiac Function ◽  
Electrical Activity ◽  
Current Density ◽  
Diffusion Tensor ◽  
Model Simulation ◽  
Correlation Coefficients ◽  
Biological Tissues ◽  
Density Maps ◽  
Current Density Imaging ◽  
Rms Error

Electro-mechanical disorders in cardiac function result in arrhythmias. Due to the non-stationary nature of these arrhythmias and, owing to lethality associated with certain type of arrhythmias, they are challenging to study. Most of the existing studies are limited in that they extract electrical activity from surface intracardiac electrical activity, either through the use of electrical or optical mapping. One way of studying current pathways inside and through biological tissues is by using Magnetic Resonance Imaging (MRI) based Low Frequency Current Density Imaging (LFCDI). For the first time CDI was used to study ex-vivo beating hearts in different cardiac states. It should be said that; this approach involves heavy logistical and procedural complexity, hence, it would be beneficial to adapt existing electrophysiological computer models to investigate and simulate current density maps specific to studying cardiac function. In achieving this, the proposed work presents an approach to model the current density maps in 3D and study the current distributions in different electrophysiological states of the heart. The structural and fiber orientation of the heart used in this study were extracted using MRI-based Diffusion Tensor Imaging. The monodomain and bidomain Aliev-Panfilov electrophysiological models were used for CDI modeling, and the results indicate that different states were distinguishable using range and correlation of simulated current density maps. The obtained results through modeling were corroborated with actual experimental CDI data from porcine hearts. Individually and comparatively, the experimental and simulation results for various states have the same trend in terms of variations (trend correlation coefficients ≥ 0.98) and state correlations (trend correlation coefficients ≥ 0.89). The results also show that the root mean square (RMS) error in average range ratios between bidomain CDI model results and real CDI data is 0.1972 and the RMS error in state correlations between bidomain CDI model results and real CDI data is 0.2833. These results indicate, as expected, the proposed bidomain model simulation of CDI corroborates well with experimental data and can serve as a valuable tool for studying lethal cardiac arrhythmias under different simulation conditions that are otherwise not possible or difficult in a real-world experimental setup.

Reverse saturation current density imaging of highly doped regions in silicon: A photoluminescence approach

2012 ◽  
Vol 106 ◽  
pp. 76-79 ◽  
Author(s):  
Jens Müller ◽  
Karsten Bothe ◽  
Sandra Herlufsen ◽  
Helge Hannebauer ◽  
Rafel Ferré ◽  
...  
Keyword(s):  
Current Density ◽  
Saturation Current ◽  
Saturation Current Density ◽  
Current Density Imaging ◽  
Reverse Saturation Current

Magnetic field and current density imaging using off-line lock-in analysis

2016 ◽  
Vol 64 ◽  
pp. 346-351
Author(s):  
M. Kögel ◽  
F. Altmann ◽  
S. Tismer ◽  
S. Brand
Keyword(s):  
Magnetic Field ◽  
Current Density ◽  
Current Density Imaging ◽  
Lock In

Sleepwalking episodes are preceded by arousal-related activation in the cingulate motor area: EEG current density imaging

2016 ◽  
Vol 127 (1) ◽  
pp. 530-536 ◽  
Author(s):  
Piotr Januszko ◽  
Szymon Niemcewicz ◽  
Tomasz Gajda ◽  
Dorota Wołyńczyk-Gmaj ◽  
Anna Justyna Piotrowska ◽  
...  
Keyword(s):  
Current Density ◽  
Motor Area ◽  
Cingulate Motor Area ◽  
Current Density Imaging
Sign in / Sign up

Export Citation Format

Share Document