Interactive near-real-time high-resolution imaging for MR-guided lumbar interventions using ZOOM imaging in an open 1.0 Tesla MRI system – initial experience

2015 ◽  
Vol 60 (6) ◽  
Author(s):  
Marcus R. Makowski ◽  
Martin Jonczyk ◽  
Florian Streitparth ◽  
Felix Guettler ◽  
Hendrik Rathke ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
Signal Intensity ◽  
Facet Joint ◽  
Pulse Sequence ◽  
Signal To Noise Ratio ◽  
Proton Density ◽  
Sequence Design ◽  
Noise Ratio ◽  
The Cost ◽  
Weighted Sequences

AbstractDifferent techniques for magnetic resonance-guided lumbar interventions have been introduced in recent years. Appropriate pulse sequence design is crucial since high spatial resolution often comes at the cost of lower temporal resolution. The purpose of this study was to evaluate the value of accelerated reduced field of view (ZOOM)-based imaging sequences for lumbar interventions.ZOOM imaging was used in 31 interventions (periradicular, facet joint, epidural infiltrations, and discography) performed in 24 patients (10 women, 14 men; age 43±13.3 years). Signal-to-noise ratio and contrast-to-noise ratio (CNR) were determined and retrospectively compared with standard preinterventional (T2 weighted), peri-interventional (proton density), and postinterventional (spectral presaturation with inversion recovery [SPIR]) imaging. Needle artifacts were assessed by direct measurement as well as with parallel and perpendicular needle profiles. Puncture times were compared to similar interventions previously performed in our department.No significant differences in signal intensities (standard/ZOOM: 152.0/151.6; p=0.136) and CNR values (2.0/4.0; p=0.487) were identified for T2-weighted sequences. The needle artifact signal intensity was comparable (648.1/747.5; p=0.172) for peri-interventional imaging. Standard interventional (fat needle: 43.8/23.4; p<0.001; muscle needle: 6.2/2.4; p<0.001) and SPIR sequences (43.3/13.9; p=0.010) showed a higher CNR than corresponding ZOOM sequences did. Needle artifacts were larger in ZOOM (2.4 mm/2.9 mm; p=0.005). The profiles revealed that ZOOM imaging delivers more overall signal intensity. The turning points of both profiles were comparable. ZOOM reduced intervention times significantly (329.1 s/228.5 s; p=0.026).ZOOM imaging is a feasible interactive sequence for lumbar interventions. It ameliorates the tradeoff between image quality and temporal resolution. Moreover, the sequence design reduces intervention times significantly.

scholarly journals Signal Intensity of Stem Diameter Variation for the Diagnosis of Drip Irrigation Water Deficit in Grapevine

Horticulturae ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 154
Author(s):  
Chen Ru ◽  
Xiaotao Hu ◽  
Wene Wang ◽  
Hui Ran ◽  
Tianyuan Song ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Signal Intensity ◽  
Signal To Noise Ratio ◽  
Water Status ◽  
Stem Diameter ◽  
Vegetative Stage ◽  
Signal To Noise ◽  
Diameter Variation ◽  
Expansion Stage ◽  
Noise Ratio

Precise irrigation management of grapevines in greenhouses requires a reliable method to easily quantify and monitor the grapevine water status to enable effective manipulation of the water stress of the plants. This study describes a study on stem diameter variations of grapevine planted in a greenhouse in the semi-arid area of Northwest China. In order to determine the applicability of signal intensity of stem diameter variation to evaluate the water status of grapevine and soil. The results showed that the relative variation curve of the grapevine stem diameter from the vegetative stage to the fruit expansion stage showed an overall increasing trend. The correlations of MDS (maximum daily shrinkage) and DI (daily increase) with meteorological factors were significant (p < 0.05), and the correlations with SWP, RWC and soil moisture were weak. Although MDS and DI can diagnose grapevine water status in time, SIMDS and SIDI have the advantages of sensitivity and signal intensity compared with other indicators. Compared with MDS and DI, the R2 values of the regression equations of SIMDS and SIDI with SWP and RWC were high, and the correlation reached a very significant level (p < 0.01). Thus, SIMDS and SIDI are more suitable for the diagnosis of grapevine water status. The SIMDS peaked at the fruit expansion stage, reaching 0.957–1.384. The signal-to-noise ratio of SIDI was higher than that of MDS across the three treatments at the vegetative stage. The value and signal-to-noise ratio of SIDI at the flowering stage were similar to those of SIMDS, while the correlation between SIDI and the soil moisture content was higher than that of SIMDS. It can be concluded that that SIDI is suitable as an indicator of water status of grapevine and soil during the vegetative and flowering stages. In addition, the signal-to-noise ratio of SIMDS during the fruit expansion and mature stages was significantly higher than that of SIDI. Therefore, SIMDS is suitable as an indicator of the moisture status of grapevine and soil during the fruit expansion and mature stages. In general, SIMDS and SIDI were very good predictors of the plant water status during the growth stage and their continuous recording offers the promising possibility of their use in automatic irrigation scheduling in grapevine.

Median Morphological Filter Design Based on the PSO Algorithm

2011 ◽  
Vol 128-129 ◽  
pp. 181-184
Author(s):  
You Lian Zhu ◽  
Cheng Huang
Keyword(s):  
Filter Design ◽  
Design Method ◽  
Signal To Noise Ratio ◽  
Pso Algorithm ◽  
Morphological Operations ◽  
Morphological Filter ◽  
Signal To Noise ◽  
Noise Ratio ◽  
The Cost ◽  
Filter Design Method

Design of morphological filter greatly depends on morphological operations and structuring elements selection. A filter design method used median closing morphological operation is proposed to enhance the image denoising ability and the PSO algorithm is introduced for structural elements selecting. The method takes the peak value signal-to-noise ratio (PSNR) as the cost function and may adaptively build unit structuring elements with zero square matrix. Experimental results show the proposed method can effectively remove impulse noise from a noisy image, especially from a low signal-to-noise ratio (SNR) image; the noise reduction performance has obvious advantages than the other.

scholarly journals NOISE STABILITY OF SIGNAL RECEPTION ALGORITHMS WITH MULTIPULSE PULSE-POSITION MODULATION

2018 ◽  
Vol 42 (1) ◽  
pp. 167-174 ◽  
Author(s):  
V. I. Parfenov ◽  
D. Y. Golovanov
Keyword(s):  
Communication Systems ◽  
Pulse Sequence ◽  
Signal To Noise Ratio ◽  
Point Of View ◽  
Estimation Accuracy ◽  
Pulse Position Modulation ◽  
Signal To Noise ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Noise Ratio

An algorithm for estimating time positions and amplitudes of a periodic pulse sequence from a small number of samples was proposed. The number of these samples was determined only by the number of pulses. The performance of this algorithm was considered on the assumption that the spectrum of the original signal is limited with an ideal low-pass filter or the Nyquist filter, and conditions for the conversion from one filter to the other were determined. The efficiency of the proposed algorithm was investigated through analyzing in which way the dispersion of estimates of time positions and amplitudes depends on the signal-to-noise ratio and on the number of pulses in the sequence. It was shown that, from this point of view, the efficiency of the algorithm decreases with increasing number of sequence pulses. Besides, the efficiency of the proposed algorithm decreases with decreasing signal-to-noise ratio.It was found that, unlike the classical maximum likelihood algorithm, the proposed algorithm does not require a search for the maximum of a multivariable function, meanwhile characteristics of the estimates are practically the same for both these methods. Also, it was shown that the estimation accuracy of the proposed algorithm can be increased by an insignificant increase in the number of signal samples.The results obtained may be used in the practical design of laser communication systems, in which the multipulse pulse-position modulation is used for message transmission. 

scholarly journals Selection and application of coils in temporomandibular joint MRI

2020 ◽  
Vol 49 (3) ◽  
pp. 20190002 ◽  
Author(s):  
Qi Sun ◽  
Min-jun Dong ◽  
Xiao-feng Tao ◽  
Meng-da Jiang ◽  
Chi Yang
Keyword(s):  
Temporomandibular Joint ◽  
Background Noise ◽  
Phased Array ◽  
Signal To Noise Ratio ◽  
Surface Coil ◽  
Proton Density ◽  
Imaging Sequence ◽  
Noise Ratio ◽  
Numerical Variation ◽  
Head Coil

Objective: To compare and evaluate the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) values between a 15-channel phased array head coil and 6-channel dS Flex M surface coil in the MRI of temporomandibular joint. Methods: 300 patients were randomly assigned to two groups: 150 patients were examined by using a 15-channel phased array head coil and the other 150 patients were scanned by using a 6-channel dS Flex M surface coil. All of the data were set in the same 6 regions of interest including the temporal lobe, condyle neck, lateral pterygoid muscle, parotid gland, the adipose area and an area of the background noise）. SNR and CNR values were measured respectively. Results: The numerical variation law of SNR and CNR values measured in regionsof interest of each group was similar, although different coils were used. There were statistically significant differences of SNR values in all of the oblique sagittal (OSag) proton density-weighted imaging, the part of OSag T 2 weighted image (T 2WI) except for SNR4 and SNR5. and oblique coronal (OCor) T 2WI sequence except for SNR2. On the contrary, SNR4 and SNR5 values in the OCor T 2WI and SNR5 values in OSag T 2WI sequences by using the surface coil were higher than those by using the head coil. There were no statistically significant intergroup differences of CNR values in OSag proton density-weighted imaging sequence except CNR1 and in OSag T 2WI sequence except CNR5. But, statistically significant differences of all the values in the OCor T 2WI sequence except for CNR1 were observed. Conclusion: Both the phased array head coil and dS Flex M surface coil can be used for temporomandibular joint MRI.

Variations in Photoreceptor Response Dynamics Across the Fly Retina

2001 ◽  
Vol 86 (2) ◽  
pp. 950-960 ◽  
Author(s):  
Brian G. Burton ◽  
Ben W. Tatler ◽  
Simon B. Laughlin
Keyword(s):  
Temporal Resolution ◽  
Light Adaptation ◽  
Signal To Noise Ratio ◽  
Calliphora Vicina ◽  
Retinal Neuron ◽  
Response Dynamics ◽  
Signal To Noise ◽  
Spatiotemporal Resolution ◽  
Temporal Properties ◽  
Noise Ratio

Gradients in the spatial properties of retinal cells and their relation to image statistics are well documented. However, less is known of gradients in temporal properties, especially at the level of the photoreceptor for which no account exists. Using light flashes and white-noise-modulated light and current stimuli, we examined the spatial and temporal properties of a single class of photoreceptor (R1–6) within the compound eyes of male blowfly, Calliphora vicina. We find that there is a trend toward higher performance at the front of the eye, both in terms of spatiotemporal resolution and signal-to-noise ratio. The receptive fields of frontal photoreceptors are narrower than those of photoreceptors at the side and back of the eye and response speeds are 20% faster. The signal-to-noise ratio at high frequencies is also greatest at the front of the eye, allowing a 30–40% higher information rate. The power spectra of signals and noise indicate that this elevation of performance results both from shorter responses to individual photons and from a more reliable registration of photon arrival times. These distinctions are characteristic of adaptational changes that normally occur on increasing illumination. However, all photoreceptors were absorbing light at approximately the same mean photon rate during our recordings. We therefore suggest that frontal photoreceptors attain a higher state of light adaptation for a given photon rate. This difference may be achieved by a higher density of (Ca2+ permeable) light-gated channels. Consistent with this hypothesis, membrane-impedance measurements show that frontal photoreceptors have a higher specific conductance than other photoreceptors. This higher conductance provides a better temporal performance but is metabolically expensive. Across the eye, temporal resolution is not proportional to spatial (optical) resolution. Neither is it matched obviously to optic flow. Instead we examine the consequences of an improved temporal resolution in the frontal region for the tracking of small moving targets, a behavior exhibited by male flies. We conclude that the temporal properties of a given class of retinal neuron can vary within a single retina and that this variation may be functionally related to the behavioral requirements of the animal.

Design and Implementation of a Flexible Interline CCD Pixel Binning Method

2011 ◽  
Vol 48-49 ◽  
pp. 373-377
Author(s):  
Tian Wei Bao ◽  
Shi Wang ◽  
Tian Yu Ma ◽  
Ya Qiang Liu
Keyword(s):  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Image Capture ◽  
Charge Coupled Device ◽  
Design And Implementation ◽  
Noise Ratio ◽  
The Cost

Pixel binning is a very important mechanism in CCD (Charge Coupled Device) image capture system. At the cost of resolution degradation, the readout speed and SNR (signal-to-noise ratio) are improved. A 3×2 pixel binning technique is reported in this paper and the driving timing sequences are presented. Compared to normal 2×2 pixel binning, this technique keeps a relative better SNR ,but in the same readout speed.

scholarly journals Applicability of deep learning-based reconstruction trained by brain and knee 3T MRI to lumbar 1.5T MRI

2021 ◽  
Vol 10 (6) ◽  
pp. 205846012110239
Author(s):  
Nobuo Kashiwagi ◽  
Hisashi Tanaka ◽  
Yuichi Yamashita ◽  
Hiroto Takahashi ◽  
Yoshimori Kassai ◽  
...  
Keyword(s):  
Deep Learning ◽  
Magnetic Resonance ◽  
Image Quality ◽  
Signal To Noise Ratio ◽  
Magnetic Resonance Images ◽  
Reconstruction Method ◽  
Signal To Noise ◽  
Scanning Time ◽  
Noise Ratio ◽  
Weighted Sequences

Background Several deep learning-based methods have been proposed for addressing the long scanning time of magnetic resonance imaging. Most are trained using brain 3T magnetic resonance images, but is unclear whether performance is affected when applying these methods to different anatomical sites and at different field strengths. Purpose To validate the denoising performance of deep learning-based reconstruction method trained by brain and knee 3T magnetic resonance images when applied to lumbar 1.5T magnetic resonance images. Material and Methods Using a 1.5T scanner, we obtained lumber T2-weighted sequences in 10 volunteers using three different scanning times: 228 s (standard), 119 s (double-fast), and 68 s (triple-fast). We compared the images obtained by the standard sequence with those obtained by the deep learning-based reconstruction-applied faster sequences. Results Signal-to-noise ratio values were significantly higher for deep learning-based reconstruction-double-fast than for standard and did not differ significantly between deep learning-based reconstruction-triple-fast and standard. Contrast-to-noise ratio values also did not differ significantly between deep learning-based reconstruction-triple-fast and standard. Qualitative scores for perceived signal-to-noise ratio and overall image quality were significantly higher for deep learning-based reconstruction-double fast and deep learning-based reconstruction-triple-fast than for standard. Average scores for sharpness, contrast, and structure visibility were equal to or higher for deep learning-based reconstruction-double-fast and deep learning-based reconstruction-triple-fast than for standard, but the differences were not statistically significant. The average scores for artifact were lower for deep learning-based reconstruction-double-fast and deep learning-based reconstruction-triple-fast than for standard, but the differences were not statistically significant. Conclusion The deep learning-based reconstruction method trained by 3T brain and knee images may reduce the scanning time of 1.5T lumbar magnetic resonance images by one-third without sacrificing image quality.

scholarly journals Performance of TGSE BLADE DWI in the diagnosis of cholesteatoma compared with RESOLVE DWI

2020 ◽  
Author(s):  
Yaru Sheng ◽  
Rujian Hong ◽  
Yan Sha ◽  
Zhongshuai Zhang ◽  
Kun Zhou ◽  
...  
Keyword(s):  
Image Quality ◽  
Pulse Sequence ◽  
Signal To Noise Ratio ◽  
Spin Echo ◽  
Quantitative Imaging ◽  
Geometric Distortion ◽  
Imaging Parameters ◽  
Diffusion Weighted ◽  
Ghosting Artifacts ◽  
Noise Ratio

Abstract Background: Based on the high resolution of soft tissue, MRI has gained increasing importance in the evaluation of cholesteatoma, especially diffusion-weighted imaging(DWI). The purpose of this study was to evaluate the role of 2D turbo gradient- and spin-echo (TGSE) diffusion-weighted (DW) pulse sequence with BLADE trajectory technique in the diagnosis of cholesteatoma at 3T and to qualitatively and quantitatively compare the image quality between the TGSE BLADE and RESOLVE methods.Method: A total of 42 patients (23 males, 19 females; age range, 7-65 years; mean, 40.1 years) with surgically confirmed cholesteatoma in the middle ear were enrolled in this study. All patients underwent DWI (both the prototype TGSE BLADE DWI sequence and RESOLVE DWI sequence) using a 3-T scanner with a 64-channel brain coil.Qualitative imaging parameters (imaging sharpness, geometric distortion, ghosting artifacts, and overall imaging quality) and quantitative imaging parameters (apparent diffusion coefficient [ADC], signal-to-noise ratio [SNR], contrast, and contrast-to-noise ratio [CNR] for the two diffusion acquisition techniques were assessed by two independent radiologists. Result: Comparison of the qualitative scores indicated that TGSE BLADE DWI produced less geometric distortion and ghosting artifacts (P<0.001) and higher image quality (P<0.001) than RESOLVE DWI. Comparison of the evaluated quantitative image parameters between TGSE and RESOLVE showed that TGSE BLADE DWI produced a significantly lower SNR (P<0.001) and higher parameter values (both contrast and CNR (P < 0.001)) than RESOLVE DWI.The ADC (P<0.001) measured by TGSE BLADE DWI (0.763×10-3 s/mm2) is significantly lower than that measured by RESOLVE DWI (0.928×10-3 s/mm2). Conclusion: Comparing with RESOLVE DWI, TGSE BLADE DWI can significantly improve the image quality of cholesteatoma by reducing magnetic sensitive artifacts, distortion, and blurring. TGSE BLADE DWI is more valuable for the diagnosis of small-sized (2mm) cholesteatoma lesions compare with RESOLVE DWI image. However, TGSE BLADE DWI also has some disadvantages: the whole image intensity is slightly low, so that the anatomical details of the air-bone interface are not well shown, which is the place to be improved in the future.

Breast MRI at very short TE (minTE): image analysis of minTE sequences on non-fat-saturated, subtracted T1-weighted images

2017 ◽  
Vol 14 (03) ◽  
pp. 160-168
Author(s):  
Evelyn Wenkel ◽  
Rolf Janka ◽  
Christian Geppert ◽  
Nadine Kaemmerer ◽  
Arndt Hartmann ◽  
...  
Keyword(s):  
Contrast Enhancement ◽  
Temporal Resolution ◽  
Signal To Noise Ratio ◽  
Breast Mri ◽  
Transverse Diameter ◽  
Final Assessment ◽  
Scan Time ◽  
Noise Ratio ◽  
The Difference ◽  
Lesion Morphology

Purpose The aim was to evaluate a minimum echo time (minTE) protocol for breast magnetic resonance imaging (MRI) in patients with breast lesions compared to a standard TE (nTE) time protocol. Methods Breasts of 144 women were examined with a 1.5 Tesla MRI scanner. Additionally to the standard gradient-echo sequence with nTE (4.8 ms), a variant with minimum TE (1.2 ms) was used in an interleaved fashion which leads to a better temporal resolution and should reduce the scan time by approximately 50 %. Lesion sizes were measured and the signal-to-noise ratio (SNR) as well as the contrast-to-noise ratio (CNR) were calculated. Subjective confidence was evaluated using a 3-point scale before looking at the nTE sequences (1 = very sure that I can identify a lesion and classify it, 2 = quite sure that I can identify a lesion and classify it, 3 = definitely want to see nTE for final assessment) and the subjective image quality of all examinations was evaluated using a four-grade scale (1 = sharp, 2 = slight blur, 3 = moderate blur and 4 = severe blur/not evaluable) for lesion and skin sharpness. Lesion morphology and contrast enhancement were also evaluated. Results With minTE sequences, no lesion was rated with “definitely want to see nTE sequences for final assessment”. The difference of the longitudinal and transverse diameter did not differ significantly (p > 0.05). With minTE, lesions and skin were rated to be significantly more blurry (p < 0.01 for lesions and p < 0.05 for skin). There was no difference between both sequences with respect to SNR, CNR, lesion morphology, contrast enhancement and detection of multifocal disease. Conclusion Dynamic breast MRI with a minTE protocol is feasible without a major loss of information (SNR, CNR, lesion morphology, contrast enhancement and lesion sizes) and the temporal resolution can be increased by a factor of 2 using minTE sequences. Key points 

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