MR venography of the brain with enhanced vessel contrast using image-domain high-pass filtering of the susceptibility phase shift

2011 ◽  
Vol 34 (5) ◽  
pp. 1218-1225 ◽  
Author(s):  
Zhaoyang Jin ◽  
Ling Xia ◽  
Min Lou ◽  
Minming Zhang ◽  
Yiping P. Du
Keyword(s):  
Phase Shift ◽  
Mr Venography ◽  
Image Domain ◽  
High Pass ◽  
The Brain

Reconstruction of the Audiogram Using Brain Stem Responses and High-Pass Noise Masking

1979 ◽  
Vol 88 (3_suppl) ◽  
pp. 1-20 ◽  
Author(s):  
Manuel Don ◽  
Jos J. Eggermont ◽  
Derald E. Brackmann
Keyword(s):  
Hearing Loss ◽  
Brain Stem ◽  
Narrow Band ◽  
Pure Tone Audiometry ◽  
Normal Hearing ◽  
Noise Masking ◽  
Specific Frequency ◽  
High Pass ◽  
The Brain ◽  
Air Conduction

Contributions to the brain stem electrical responses (BSER) presumably initiated from specific frequency regions of the cochlea with center frequencies similar to the major audiometric frequencies (0.5, 1, 2, 4, and 8 kHz) are derived by the application of a high-pass noise masking technique utilizing click stimuli. In normal hearing subjects, these derived narrow-band responses from the midfrequency regions (4, 2, and 1 kHz) can be recognized at click levels as low as 10 dB HL. For the frequency regions around 8 kHz and 0.5 kHz, these derived responses can be discerned at click levels of 30 dB HL and higher. When one uses the lowest click level at which these derived responses can be obtained from a given frequency region, the differences between a patient with a hearing loss and a normal hearing subject correlate well with the amount of hearing loss (air conduction) recorded by conventional pure tone audiometry. Use of the high-pass noise masking technique to reconstruct the audiogram may be of great potential value in assessing young children and other individuals who cannot or will not respond to conventional audiometry.

State of the venous system in patients with Pseudotumor cerebri

2021 ◽  
Vol 26 (2) ◽  
pp. 37-42
Author(s):  
N. V. Shuleshova ◽  
N. I. Panchenko ◽  
I. V. Kupriyanova
Keyword(s):  
Mr Angiography ◽  
Vascular System ◽  
Pseudotumor Cerebri ◽  
Mr Venography ◽  
Venous Outflow ◽  
Brain Vessels ◽  
Pseudotumor Cerebri Syndrome ◽  
Visual Disorders ◽  
The Brain

The article describes two clinical cases of idiopathic intracranial hypertension, the first manifestation of which was the development of retroorbital headache and the visual disorders. Leading in the clinical picture of the disease in both cases was the detection of stagnant optic nerve discs on the fundus. In both patients, the vascular system of the brain was examined using duplex scanning of the neck and brain vessels, MR angiography and MR venography, and in one case — SCT angiography, a lumbar puncture was performed with the study of cerebrospinal fluid (CSF). An increase in CSF pressure was found, accompanied by changes in the large venous vessels of the skull and brain. This suggests a significant role of venous outflow disorders in the development of Pseudotumor cerebri syndrome.

Spike Phase Shift Relative to Beta Oscillations Mediates Modality Selection

2020 ◽  
Vol 30 (10) ◽  
pp. 5431-5448
Author(s):  
Yanfang Zuo ◽  
Yanwang Huang ◽  
Dingcheng Wu ◽  
Qingxiu Wang ◽  
Zuoren Wang
Keyword(s):  
Phase Shift ◽  
Posterior Parietal Cortex ◽  
Visual Stimuli ◽  
Spike Timing ◽  
Male Rats ◽  
Top Down ◽  
Beta Oscillations ◽  
Neuronal Spike ◽  
Beta Power ◽  
The Brain

Abstract How does the brain selectively process signals from stimuli of different modalities? Coherent oscillations may function in coordinating communication between neuronal populations simultaneously involved in such cognitive behavior. Beta power (12–30 Hz) is implicated in top-down cognitive processes. Here we test the hypothesis that the brain increases encoding and behavioral influence of a target modality by shifting the relationship of neuronal spike phases relative to beta oscillations between primary sensory cortices and higher cortices. We simultaneously recorded neuronal spike and local field potentials in the posterior parietal cortex (PPC) and the primary auditory cortex (A1) when male rats made choices to either auditory or visual stimuli. Neuronal spikes exhibited modality-related phase locking to beta oscillations during stimulus sampling, and the phase shift between neuronal subpopulations demonstrated faster top-down signaling from PPC to A1 neurons when animals attended to auditory rather than visual stimuli. Importantly, complementary to spike timing, spike phase predicted rats’ attended-to target in single trials, which was related to the animals’ performance. Our findings support a candidate mechanism that cortices encode targets from different modalities by shifting neuronal spike phase. This work may extend our understanding of the importance of spike phase as a coding and readout mechanism.

Is Venous Stenosis Associated with Iron Deposition in the Brain? Preliminary Results of a Study of MR Venography and Susceptibility-Weighted Imaging (P05.124)

Neurology ◽  
2012 ◽  
Vol 78 (Meeting Abstracts 1) ◽  
pp. P05.124-P05.124
Author(s):  
A. Rae-Grant ◽  
M. Phillips ◽  
S. Jones ◽  
C. Diaconu ◽  
S. Ramesh ◽  
...  
Keyword(s):  
Iron Deposition ◽  
Susceptibility Weighted Imaging ◽  
Mr Venography ◽  
Preliminary Results ◽  
Venous Stenosis ◽  
The Brain

scholarly journals Background-Suppressed MR Venography of the Brain Using Magnitude Data: A High-Pass Filtering Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Zhaoyang Jin ◽  
Ling Xia ◽  
Minming Zhang ◽  
Yiping P. Du
Keyword(s):  
Field Inhomogeneity ◽  
Signal Loss ◽  
Background Signal ◽  
Pass Filter ◽  
High Pass ◽  
The Brain ◽  
Minimum Intensity ◽  
Venous Vasculature ◽  
Filtering Approach ◽  
Peripheral Regions

Conventional susceptibility-weighted imaging (SWI) uses both phase and magnitude data for the enhancement of venous vasculature and, thus, is subject to signal loss in regions with severe field inhomogeneity and in the peripheral regions of the brain in the minimum-intensity projection. The purpose of this study is to enhance the visibility of the venous vasculature and reduce the artifacts in the venography by suppressing the background signal in postprocessing. A high-pass filter with an inverted Hamming window or an inverted Fermi window was applied to the Fourier domain of the magnitude images to enhance the visibility of the venous vasculature in the brain after data acquisition. The high-pass filtering approach has the advantages of enhancing the visibility of small veins, diminishing the off-resonance artifact, reducing signal loss in the peripheral regions of the brain in projection, and nearly completely suppressing the background signal. The proposed postprocessing technique is effective for the visualization of small venous vasculature using the magnitude data alone.

scholarly journals Reduction of artifacts in susceptibility-weighted MR venography of the brain

2008 ◽  
Vol 28 (2) ◽  
pp. 327-333 ◽  
Author(s):  
Zhaoyang Jin ◽  
Ling Xia ◽  
Yiping P. Du
Keyword(s):  
Mr Venography ◽  
The Brain

Analog and Digital Filtering of the Brain Stem Auditory Evoked Response

1989 ◽  
Vol 98 (7) ◽  
pp. 508-514 ◽  
Author(s):  
Kevin T. Kavanagh ◽  
Renaee Franks
Keyword(s):  
Phase Shift ◽  
Wave Amplitude ◽  
Cutoff Frequency ◽  
Evoked Response ◽  
Auditory Evoked Potential ◽  
Pass Filter ◽  
Auditory Evoked Response ◽  
High Pass Filter ◽  
High Pass ◽  
Zero Phase

This study compared the filtering effects on the auditory evoked potential of zero and standard phase shift digital filters (the former was a mathematical approximation of a standard Butterworth filter). Conventional filters were found to decrease the height of the evoked response in the majority of waveforms compared to zero phase shift filters. a 36-dB/octave zero phase shift high pass filter with a cutoff frequency of 100 Hz produced a 16% reduction in wave amplitude compared to the unfiltered control. a 36-dB/octave, 100-Hz standard phase shift high pass filter produced a 41% reduction, and a 12-dB/octave, 150-Hz standard phase shift high pass filter produced a 38% reduction in wave amplitude compared to the unfiltered control. a decrease in the mean along with an increase in the variability of wave IV/V latency was also noted with conventional compared to zero phase shift filters. The increase in the variability of the latency measurement was due to the difficulty in waveform identification caused by the phase shift distortion of the conventional filter along with the variable decrease in wave latency caused by phase shifting responses with different spectral content. Our results indicated that a zero phase shift high pass filter of 100 Hz was the most desirable filter studied for the mitigation of spontaneous brain activity and random muscle artifact.

Persistent Falcine Venous Sinus in Two Patients with Atretic Parietal Cephaloceles. An MRI and MRV Evaluation

2005 ◽  
Vol 18 (2) ◽  
pp. 197-200
Author(s):  
I. Tsitouridis ◽  
F. Goutsaridou ◽  
K. Tsitouridis ◽  
S. Chondromatidou ◽  
M. Emmanouilidou ◽  
...  
Keyword(s):  
Superior Sagittal Sinus ◽  
Venous Sinus ◽  
Vertical Position ◽  
Calvarial Defect ◽  
Mr Venography ◽  
Normal Position ◽  
Falcine Sinus ◽  
Sagittal Sinus ◽  
Mri Study ◽  
The Brain

We report two patients with persistent falcine vein associated with atretic parietal cephaloceles. Two children, aged two and eight months, were admitted to our department for MRI examination of the brain because of palpable parietal subscalp lesions. MRI study of the brain and MR-venography revealed a falcine sinus joining the superior sagittal sinus in a vertical position. The straight sinus was absent in its normal position. The parietal subscalp lesions were cyst-like formations under the skin associated with a small calvarial defect. The lesions were assumed to be atretic cephaloceles.

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