Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 184
Filter
1.
Article in Chinese | WPRIM | ID: wpr-928898

ABSTRACT

To solve the problem of real-time detection and removal of EEG signal noise in anesthesia depth monitoring, we proposed an adaptive EEG signal noise detection and removal method. This method uses discrete wavelet transform to extract the low-frequency energy and high-frequency energy of a segment of EEG signals, and sets two sets of thresholds for the low-frequency band and high-frequency band of the EEG signal. These two sets of thresholds can be updated adaptively according to the energy situation of the most recent EEG signal. Finally, we judge the level of signal interference according to the range of low-frequency energy and high-frequency energy, and perform corresponding denoising processing. The results show that the method can more accurately detect and remove the noise interference in the EEG signal, and improve the stability of the calculated characteristic parameters.


Subject(s)
Algorithms , Electroencephalography , Signal Processing, Computer-Assisted , Signal-To-Noise Ratio , Wavelet Analysis
2.
Article in Chinese | WPRIM | ID: wpr-928877

ABSTRACT

This paper analyzes the shortcomings of the existing pure tone audiometers, and proposes a system to realize pure tone audiometry and speech audiometry with a new DSP processor. The pure tone test signal produced by the system has accurate frequency, high signal-to-noise ratio, and small harmonic distortion. The noise generator that comes with DSP adds a band-pass filter to realize the generation of narrow-band noise. At the same time, due to the modular structure of software design, the system has good ease of use and scalability. The test results show that the hearing test system has excellent performance and can be better used in hearing medical diagnosis.


Subject(s)
Audiometry, Pure-Tone/methods , Hearing , Noise , Signal-To-Noise Ratio
3.
Article in Chinese | WPRIM | ID: wpr-928227

ABSTRACT

Heart sound signal is a kind of physiological signal with nonlinear and nonstationary features. In order to improve the accuracy and efficiency of the phonocardiogram (PCG) classification, a new method was proposed by means of support vector machine (SVM) in which the complete ensemble empirical modal decomposition with adaptive noise (CEEMDAN) permutation entropy was as the eigenvector of heart sound signal. Firstly, the PCG was decomposed by CEEMDAN into a number of intrinsic mode functions (IMFs) from high to low frequency. Secondly, the IMFs were sifted according to the correlation coefficient, energy factor and signal-to-noise ratio. Then the instantaneous frequency was extracted by Hilbert transform, and its permutation entropy was constituted into eigenvector. Finally, the accuracy of the method was verified by using a hundred PCG samples selected from the 2016 PhysioNet/CinC Challenge. The results showed that the accuracy rate of the proposed method could reach up to 87%. In comparison with the traditional EMD and EEMD permutation entropy methods, the accuracy rate was increased by 18%-24%, which demonstrates the efficiency of the proposed method.


Subject(s)
Entropy , Heart Sounds , Signal Processing, Computer-Assisted , Signal-To-Noise Ratio , Support Vector Machine
4.
Article in Chinese | WPRIM | ID: wpr-878697

ABSTRACT

Objective To determine the appropriate averaging strategy for pancreatic perfusion datasets to create images for routine reading of insulinoma.Methods Thirty-nine patients undergoing pancreatic perfusion CT in Peking Union Medical College Hospital and diagnosed as insulinoma by pathology were enrolled in this retrospective study.The time-density curve of abdominal aorta calculated by software dynamic angio was used to decide the timings for averaging.Five strategies,by averaging 3,5,7,9 and 11 dynamic scans in perfusion,all including peak enhancement of the abdominal aorta,were investigated in the study.The image noise,pancreas signal-to-noise ratio(SNR),lesion contrast and lesion contrast-to-noise ratio(CNR)were recorded and compared.Besides,overall image quality and insulinoma depiction were also compared.ANOVA and Friedman's test were performed.Results The image noise decreased and the SNR of pancreas increased with the increase in averaging time points(all P0.99)and were higher than that of the first group(all P<0.05).There was no significant difference in overall image quality among the 5 groups(P=0.977).Conclusions Image averaged from 5 scans showed moderate image noise,pancreas SNR and relatively high lesion contrast and lesion CNR.Therefore,it is advised to be used in image averaging to detect insulinoma.


Subject(s)
Contrast Media , Humans , Insulinoma/diagnostic imaging , Pancreas/diagnostic imaging , Pancreatic Neoplasms/diagnostic imaging , Perfusion , Radiographic Image Interpretation, Computer-Assisted , Reading , Retrospective Studies , Signal-To-Noise Ratio
5.
Article in Chinese | WPRIM | ID: wpr-879204

ABSTRACT

Denoising methods based on wavelet analysis and empirical mode decomposition cannot essentially track and eliminate noise, which usually cause distortion of heart sounds. Based on this problem, a heart sound denoising method based on improved minimum control recursive average and optimally modified log-spectral amplitude is proposed in this paper. The proposed method uses a short-time window to smoothly and dynamically track and estimate the minimum noise value. The noise estimation results are used to obtain the optimal spectrum gain function, and to minimize the noise by minimizing the difference between the clean heart sound and the estimated clean heart sound. In addition, combined with the subjective analysis of spectrum and the objective analysis of contribution to normal and abnormal heart sound classification system, we propose a more rigorous evaluation mechanism. The experimental results show that the proposed method effectively improves the time-frequency features, and obtains higher scores in the normal and abnormal heart sound classification systems. The proposed method can help medical workers to improve the accuracy of their diagnosis, and also has great reference value for the construction and application of computer-aided diagnosis system.


Subject(s)
Algorithms , Heart Sounds , Humans , Signal Processing, Computer-Assisted , Signal-To-Noise Ratio , Wavelet Analysis
6.
Article in Chinese | WPRIM | ID: wpr-828170

ABSTRACT

Spike recorded by multi-channel microelectrode array is very weak and susceptible to interference, whose noisy characteristic affects the accuracy of spike detection. Aiming at the independent white noise, correlation noise and colored noise in the process of spike detection, combining principal component analysis (PCA), wavelet analysis and adaptive time-frequency analysis, a new denoising method (PCWE) that combines PCA-wavelet (PCAW) and ensemble empirical mode decomposition is proposed. Firstly, the principal component was extracted and removed as correlation noise using PCA. Then the wavelet-threshold method was used to remove the independent white noise. Finally, EEMD was used to decompose the noise into the intrinsic modal function of each layer and remove the colored noise. The simulation results showed that PCWE can increase the signal-to-noise ratio by about 2.67 dB and decrease the standard deviation by about 0.4 μV, which apparently improved the accuracy of spike detection. The results of measured data showed that PCWE can increase the signal-to-noise ratio by about 1.33 dB and reduce the standard deviation by about 18.33 μV, which showed its good denoising performance. The results of this study suggests that PCWE can improve the reliability of spike signal and provide an accurate and effective spike denoising new method for the encoding and decoding of neural signal.


Subject(s)
Algorithms , Microelectrodes , Principal Component Analysis , Reproducibility of Results , Signal Processing, Computer-Assisted , Signal-To-Noise Ratio , Wavelet Analysis
7.
Article in Chinese | WPRIM | ID: wpr-826356

ABSTRACT

To evaluate the effect of monochromatic energy image on inferior vena cava imaging quality on dual-layer detector spectral CT. Totally 39 patients who were clinically suspected of abdominal disease and referred to perform contrast-enhanced computed tomography(CT)were prospectively enrolled and underwent abdominal examination using a single-source,dual-detector spectral CT.The delayed phase scan was performed 3 minutes after injection of 60 ml of iopamidol(320 mg/ml)at a rate of 3 ml/s.The raw images were reconstructed to obtain conventional mixed energy images and spectral based images(SBI).The 40,50,60,and 70 keV single energy images were obtained.The CT value,noise,and signal-to-noise(SNR)of inferior vena cava and the contrast-to-noise(CNR)of inferior vena cava relative to psoas major on conventional mixed energy images and the 40,50,60,70 keV single energy images were measured.The SNRs and CNRs on monoenergetic 40-70 keV images were compared with polychromatic 120 kVp images.ANOVA was used to compare the CT value,noise,SNR,and CNR among these five groups.The optimal monoenergetic image set was chosen. The differences in CT value,noise,SNR,CNR of inferior vena cava were statistically significant among five groups(all <0.05).The SNR and CNR in 40 keV group and 50 keV group were significantly higher than those in other groups(all <0.05).The SNR of 40 keV group was significantly higher than that of 50 keV group(=0.002).The CNR of 40 keV group was not statistical different compared with that of 50 keV group(=0.630). 40 keV is the optimal monoenergetic energy level for the inferior vena cava on dual-layer detector spectral CT and may be valuable for the diagnosis of inferior vena cava disease.


Subject(s)
Abdomen , Humans , Radiographic Image Interpretation, Computer-Assisted , Signal-To-Noise Ratio , Tomography, X-Ray Computed , Vena Cava, Inferior
8.
CoDAS ; 32(5): e20180272, 2020. tab
Article in Portuguese | LILACS | ID: biblio-1133524

ABSTRACT

RESUMO Objetivo: Validar o conteúdo de um instrumento para mensuração do esforço auditivo para indivíduos com perda auditiva. Método: Trata-se de um estudo de validação, desenvolvido em duas fases, sendo a fase 1 o planejamento e desenvolvimento da primeira versão do instrumento e a fase 2 a investigação das evidências de validade baseadas no conteúdo do instrumento e desenvolvimento da versão final para mensuração de esforço auditivo. Participaram dez profissionais com expertise na área audiológica, com mais de cinco anos de experiência. O instrumento a ser validado foi composto por três partes: I - "percepção de fala de logatomas e esforço auditivo"; II - "esforço auditivo e memória operacional"; e III - "percepção de sentenças sem sentido e memória operacional", apresentadas de forma monoaural no silêncio e nas relações sinal-ruído +5dB, 0dB e -5dB. Foi realizada a análise descritiva das sugestões do comitê de fonoaudiólogos e do índice de validade de conteúdo individual e total. Resultados: Os resultados mostraram que as partes I e III do instrumento proposto atingiram o índice de validade de conteúdo total acima de 0,78, ou seja, os itens apresentados não necessitaram de modificações em seu constructo. Conclusão: As evidências de validade estudadas permitiram relevantes modificações e tornaram esse instrumento adequado ao seu constructo.


ABSTRACT Purpose: To validate the content of an instrument to measure listening effort for hearing-impaired individuals. Method: This is a validation study, developed in two stages, which the Stage 1 is the planning and development of the first version of the instrument, and Stage 2 the investigation of the evidences of validity based on the content and development of the final version of the instrument to measure listening effort. Ten professionals with expertise in the field of audiology, with more than five years of clinical experience participated in this study. The instrument to be validated was composed of three parts: I - "speech perception of logatomes and listening effort"; II - "listening effort and working memory" and; III - "speech perception of meaningless sentences and working memory" and they were presented monoaurally, in quiet and in the signal-to-noise ratios + 5dB, 0dB and -5dB. It was conducted a descriptive analysis regarding the suggestions of the committee judge audiologists and the analysis of the individual and scale content validity index. Results: The results showed that parts I and III which constitute the proposed instrument reached a scale content validity index above 0.78, which means that the presented items did not need modification in their construct. Conclusion: The evidences of validity studied allowed relevant modifications and made this instrument adequate to its construct.


Subject(s)
Humans , Speech Perception , Persons With Hearing Impairments , Auditory Perception , Signal-To-Noise Ratio , Memory, Short-Term
9.
Article in English | WPRIM | ID: wpr-764228

ABSTRACT

BACKGROUND AND OBJECTIVES: This study compared the perception of mono-syllabic and bisyllabic words in Tamil by young normal hearing adults in the presence of multi-talker speech babble at two signal-to-noise ratios (SNRs). Further for this comparison, a speech perception in noise test was constructed using existing mono-syllabic and bi-syllabic word lists in Tamil. SUBJECTS AND METHODS: A total of 30 participants with normal hearing in the age range of 18 to 25 years participated in the study. Speech-in-noise test in Tamil (SPIN-T) constructed using mono-syllabic and bi-syllabic words in Tamil was used as stimuli. The stimuli were presented in the background of multi-talker speech babble at two SNRs (0 dB and +10 dB SNR). RESULTS: The effect of noise on SPIN-T varied with SNR. All the participants performed better at +10 dB SNR, the higher of the two SNRs considered. Additionally, at +10 dB SNR performance did not vary significantly for neither mono-syllabic or bi-syllabic words. However, a significant difference existed at 0 dB SNR. CONCLUSIONS: The current study indicated that higher SNR leads to better performance. In addition, bi-syllabic words were identified with minimal errors compared to mono-syllabic words. Spectral cues were the most affected in the presence of noise leading to more of place of articulation errors for both mono-syllabic and bi-syllabic words.


Subject(s)
Adult , Cues , Hearing , Humans , Noise , Signal-To-Noise Ratio , Speech Perception , Young Adult
10.
Article in English | WPRIM | ID: wpr-764225

ABSTRACT

BACKGROUND AND OBJECTIVES: Many studies have reported no benefit of sound localization, but improved speech understanding in noise after treating patients with single-sided deafness (SSD). Furthermore, their performances provided a large individual difference. The present study aimed to measure the ability of speech perception and gap detection in noise for the SSD patients to better understand their hearing nature.


Subject(s)
Deafness , Hearing , Hearing Loss , Hearing Loss, Conductive , Humans , Individuality , Noise , Plastics , Sample Size , Signal-To-Noise Ratio , Silver Sulfadiazine , Sound Localization , Speech Perception , Young Adult
11.
Article in English | WPRIM | ID: wpr-763952

ABSTRACT

OBJECTIVES: In this paper, we present an efficient method to visualize computed tomography (CT) datasets using ambient occlusion, which is a global illumination technique that adds depth cues to the output image. We can change the transfer function (TF) for volume rendering and generate output images in real time. METHODS: In preprocessing, the mean and standard deviation of each local vicinity are calculated. During rendering, the ambient light intensity is calculated. The calculation is accelerated on the assumption that the CT value of the local vicinity of each point follows the normal distribution. We approximate complex TF forms with a smaller number of connected line segments to achieve additional acceleration. Ambient occlusion is combined with the existing local illumination technique to produce images with depth in real time. RESULTS: We tested the proposed method on various CT datasets using hand-drawn TFs. The proposed method enabled real-time rendering that was approximately 40 times faster than the previous method. As a result of comparing the output image quality with that of the conventional method, the average signal-to-noise ratio was approximately 40 dB, and the image quality did not significantly deteriorate. CONCLUSIONS: When rendering CT images with various TFs, the proposed method generated depth-sensing images in real time.


Subject(s)
Acceleration , Computer Systems , Cues , Dataset , Lighting , Mathematical Computing , Methods , Signal-To-Noise Ratio
12.
Neuroscience Bulletin ; (6): 369-377, 2019.
Article in English | WPRIM | ID: wpr-775470

ABSTRACT

Immediate-early genes (IEGs) have long been used to visualize neural activations induced by sensory and behavioral stimuli. Recent advances in imaging techniques have made it possible to use endogenous IEG signals to visualize and discriminate neural ensembles activated by multiple stimuli, and to map whole-brain-scale neural activation at single-neuron resolution. In addition, a collection of IEG-dependent molecular tools has been developed that can be used to complement the labeling of endogenous IEG genes and, especially, to manipulate activated neural ensembles in order to reveal the circuits and mechanisms underlying different behaviors. Here, we review these techniques and tools in terms of their utility in studying functional neural circuits. In addition, we provide an experimental strategy to measure the signal-to-noise ratio of IEG-dependent molecular tools, for evaluating their suitability for investigating relevant circuits and behaviors.


Subject(s)
Animals , Brain , Metabolism , Gene Expression Profiling , Methods , Genes, Immediate-Early , Humans , Molecular Imaging , Methods , Neural Pathways , Metabolism , Neurons , Metabolism , Signal-To-Noise Ratio
13.
Article in Chinese | WPRIM | ID: wpr-774169

ABSTRACT

Taking advantages of the sparsity or compressibility inherent in real world signals, compressed sensing (CS) can collect compressed data at the sampling rate much lower than that needed in Shannon's theorem. The combination of CS and low rank modeling is used to medical imaging techniques to increase the scanning speed of cardiac magnetic resonance (CMR), alleviate the patients' suffering and improve the images quality. The alternating direction method of multipliers (ADMM) algorithm is proposed for multiscale low rank matrix decomposition of CMR images. The algorithm performance is evaluated quantitatively by the peak signal to noise ratio (PSNR) and relative norm error (RLNE), with the human visual system and the local region magnification as the qualitative comparison. Compared to L + S, kt FOCUSS, k-t SPARSE SENSE algorithms, experimental results demonstrate that the proposed algorithm can achieve the best performance indices, and maintain the most detail features and edge contours. The proposed algorithm can encourage the development of fast imaging techniques, and improve the diagnoses values of CMR in clinical applications.


Subject(s)
Algorithms , Heart , Diagnostic Imaging , Humans , Magnetic Resonance Imaging , Signal-To-Noise Ratio
14.
Article in Chinese | WPRIM | ID: wpr-772117

ABSTRACT

The low-resolution ultrasound images have poor visual effects. Herein we propose a method for generating clearer intravascular ultrasound images based on super-resolution reconstruction combined with generative adversarial networks. We used the generative adversarial networks to generate the images by a generator and to estimate the authenticity of the images by a discriminator. Specifically, the low-resolution image was passed through the sub-pixel convolution layer -feature channels to generate -feature maps in the same size, followed by realignment of the corresponding pixels in each feature map into × sub-blocks, which corresponded to the sub-block in a high-resolution image; after amplification, an image with a -time resolution was generated. The generative adversarial networks can obtain a clearer image through continuous optimization. We compared the method (SRGAN) with other methods including Bicubic, super-resolution convolutional network (SRCNN) and efficient sub-pixel convolutional network (ESPCN), and the proposed method resulted in obvious improvements in the peak signal-to-noise ratio (PSNR) by 2.369 dB and in structural similarity index by 1.79% to enhance the diagnostic visual effects of intravascular ultrasound images.


Subject(s)
Blood Vessels , Diagnostic Imaging , Endosonography , Methods , Image Enhancement , Methods , Image Processing, Computer-Assisted , Methods , Signal-To-Noise Ratio
15.
Article in English | WPRIM | ID: wpr-786499

ABSTRACT

PURPOSE: The treatment efficiency of ⁹⁰Y and providing reliable estimates of activity are evaluated by SPECT imaging of bremsstrahlung radiation released during beta therapy. In this technique, the resulting spectrum from ⁹⁰Y is very complex and continuous, which creates difficulties on the imaging protocol. Moreover, collimator geometry has an impressive effect on the spatial resolution, system sensitivity, image contrast, and the signal-to-noise ratio (SNR), which should be optimized.METHODS: We evaluated the effect of energy window width, reconstruction algorithms, and different geometries of a medium-energy (ME) parallel-hole collimator on the image contrast and SNR of ⁹⁰Y SPECT images. The Siemens E.Cam gamma camera equipped with a ME collimator and a digital Jaszczak phantom were simulated by SIMIND Monte Carlo program to generate the ⁹⁰Y bremsstrahlung SPECT images.RESULTS: Our results showed that optimal image quality can be acquired by the reconstruction algorithm of OS-EM in the energy window width of 60 to 400 keV for ⁹⁰Y bremsstrahlung SPECT imaging. Furthermore, the optimal values of the hole diameter and hole length of a ME collimator were obtained 0.235 and 4.4 cm, respectively.CONCLUSIONS: The acquired optimal ME collimator and energy window along with using a suitable reconstruction algorithm lead to improved contrast and SNR of ⁹⁰Y bremsstrahlung images of hot spheres of the digital Jaszczak phantom. This can improve the accuracy and precision of the ⁹⁰Y activity distribution estimation after radioembolization in targeted radionuclide therapy.


Subject(s)
Gamma Cameras , Signal-To-Noise Ratio , Tomography, Emission-Computed, Single-Photon
16.
Article in English | WPRIM | ID: wpr-786470

ABSTRACT

PURPOSE: Recently, a new Bayesian Penalized Likelihood (BPL) Reconstruction Algorithm was introduced by GE Healthcare, Q.Clear; it promises to provide better PET image resolution compared to the widely used Ordered Subset Expectation Maximization (OSEM). The aimof this study is to compare the performance of these two algorithms on several types of findings, in terms of image quality, lesion detectability, sensitivity, and specificity.METHODS: Between September 6th 2017 and July 31st 2018, 663 whole body 18F-FDG PET/CT scans were performed at the Nuclear Medicine Department of S. Martino Hospital (Belluno, Italy). Based on the availability of clinical/radiological follow-up data, 240 scans were retrospectively reviewed. For each scan, a hypermetabolic finding was selected, reporting both for OSEM and Q.Clear: SUVmax and SUVmean values of the finding, the liver and the background close to the finding; size of the finding; percentage variations of SUVmax and SUVmean. Each finding was subsequently correlated with clinical and radiological follow-up, to define its benign/malignant nature.RESULTS: Overall, Q.Clear improved the SUVvalues in each scan, especially in small findings (< 10mm), high SUVmax values (≥ 10), and medium/low backgrounds. Furthermore, Q.Clear amplifies the signal of hypermetabolic findings without modifying the background signal, which leads to an increase in signal-to-noise ratio, improving overall image quality. Finally, Q.Clear did not affect PET sensitivity or specificity, in terms of number of reported findings and characterization of their nature.CONCLUSIONS: Q.Clear is an iterative algorithm that improves significantly the quality of PET images compared to OSEM, increasing the SUVmax of findings (in particular for small findings) and the signal-to-noise ratio. However, due to the intrinsic characteristics of this algorithm, it will be necessary to adapt and/or modify the current interpretative criteria based of quantitative evaluation, to avoid an overestimation of the disease burden.


Subject(s)
Delivery of Health Care , Evaluation Studies as Topic , Fluorodeoxyglucose F18 , Follow-Up Studies , Liver , Nuclear Medicine , Positron Emission Tomography Computed Tomography , Retrospective Studies , Sensitivity and Specificity , Signal-To-Noise Ratio
17.
Biomedical Engineering Letters ; (4): 467-479, 2019.
Article in English | WPRIM | ID: wpr-785528

ABSTRACT

Myoelectric prosthesis requires a sensor that can reliably capture surface electromyography (sEMG) signal from amputees for its controlled operation. The main problems with the presently available EMG devices are their extremely high cost, large response time, noise susceptibility, less amplitude sensitivity, and larger size. This paper proposes a compact and affordable EMG sensor for the prosthetic application. The sensor consists of an electrode interface, signal conditioning unit, and power supply unit all encased in a single package. The performance of dry electrodes employed in the skin interface was compared with the conventional Ag/AgCl electrodes, and the results were found satisfactory. The envelope detection technique in the sensor based on the tuned RC parameters enables the generation of smooth, faster, and repeatable EMG envelope irrespective of signal strength and subject variability. The output performance of the developed sensor was compared with commercial EMG sensor regarding signal-to-noise ratio, sensitivity, and response time. To perform this, EMG data with both devices were recorded for 10 subjects (3 amputees and 7 healthy subjects). The results showed 1.4 times greater SNR values and 45% higher sensitivity of the developed sensor than the commercial EMG sensor. Also, the proposed sensor was 57% faster than the commercial sensor in producing the output response. The sEMG sensor was further tested on amputees to control the operation of a self-designed 3D printed prosthetic hand. With proportional control scheme, the myoelectric hand setup was able to provide quicker and delicate grasping of objects as per the strength of the EMG signal.


Subject(s)
Amputees , Electric Power Supplies , Electrodes , Electromyography , Hand Strength , Hand , Humans , Noise , Prostheses and Implants , Reaction Time , Signal-To-Noise Ratio , Skin
18.
Biomedical Engineering Letters ; (4): 407-411, 2019.
Article in English | WPRIM | ID: wpr-785512

ABSTRACT

A joint time–frequency localized three-band biorthogonal wavelet filter bank to compress Electrocardiogram signals is proposed in this work. Further, the use of adaptive thresholding and modified run-length encoding resulted in maximum data volume reduction while guaranteeing reconstructing quality. Using signal-to-noise ratio, compression ratio (C(R)), maximum absolute error (E(MA)), quality score (Q(s)), root mean square error, compression time (C(T)) and percentage root mean square difference the validity of the proposed approach is studied. The experimental results deduced that the performance of the proposed approach is better when compared to the two-band wavelet filter bank. The proposed compression method enables loss-less data transmission of medical signals to remote locations for therapeutic usage.


Subject(s)
Electrocardiography , Joints , Methods , Signal-To-Noise Ratio
19.
Article in Chinese | WPRIM | ID: wpr-813050

ABSTRACT

To explore the value of the third generation dual-source computed tomography (CT) convolution kernel in display of pulmonary ground-glass nodule (GGN) in transverse image reconstruction.
 Methods: A total of 52 lung adenocarcinoma patients with lung CT data were selected from February 2018 to January 2019 for this study. The pulmonary CT data were reconstructed by convolutional nucleus B157, Br54, and Br49. The signal-to-noise ratio (SNR), the contrast-to-noise ratio (CNR), and the standard deviation (SD) of the image at the GGN were used as the objective evaluation standard of image quality. Subjective image quality was scored by 2 radiologists from 3 aspects (overall image quality, noise, and lesion outline).
 Results: Objective image quality evaluation, SNR and CNR of reconstructed convolution kernel Br49 (SNR: 11.36±5.39, CNR: 7.19±4.29), Br54 (SNR: 8.30±3.35, CNR: 5.09±2.86) are greater than those of Bl57 (SNR: 4.18±2.10, CNR: 3.25±1.78; all P<0.01). SD of reconstructed convolution kernel Br49 (61.80±20.17) and Br54 (80.45±20.31) is smaller than that of Bl57 (137.92±31.11, both P<0.01). In the subjective image quality evaluation, the overall image quality score 5.0(4.5, 5.0) of Br54 was higher than that of all other images [Br49: 3.0(3.0, 4.0), Bl57: 3.0(3.0, 3.5); both P<0.05]. The Br54 image showed that the lesion contour ability score 5.0(4.0, 5.0) was higher than all other images [Br49: 4.0(4.0, 5.0), Bl57: 3.0(3.0, 3.0); both P<0.05]; Br49 image noise score 3.0(3.0, 3.0) is the lowest one [Br54 4.0(4.0, 4.0), Bl57 5.0(5.0, 5.0); both P<0.05].
 Conclusion: The reasonable selection of CT convolution kernel plays an important role in the subjective and objective image quality of GGN. It is suggested that Br54 should be used as the reconstruction of convolutional kernel in pulmonary ground glass nodules, which is helpful for doctors to find and diagnose GGN.


Subject(s)
Algorithms , Humans , Radiation Dosage , Radiographic Image Interpretation, Computer-Assisted , Signal-To-Noise Ratio , Tomography, X-Ray Computed
20.
Korean Journal of Radiology ; : 1167-1175, 2019.
Article in English | WPRIM | ID: wpr-760284

ABSTRACT

OBJECTIVE: To compare the objective and subjective image quality indicators and radiation doses of computed tomography (CT) venography performed using model-based iterative reconstruction (MBIR) at 80 kVp and adaptive statistical iterative reconstruction (ASIR)-V at 70 kVp. MATERIALS AND METHODS: Eighty-three patients who had undergone CT venography of the lower extremities with MBIR at 80 kVp (Group A; 21 men and 20 women; mean age, 55.5 years) or ASIR-V at 70 kVp (Group B; 18 men and 24 women; mean age, 57.3 years) were enrolled. Two radiologists retrospectively evaluated the objective (vascular enhancement, image noise, signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR]) and subjective (quantum mottle, delineation of contour, venous enhancement) image quality indicators at the inferior vena cava and femoral and popliteal veins. Clinical information, radiation dose, reconstruction time, and objective and subjective image quality indicators were compared between groups A and B. RESULTS: Vascular enhancement, SNR, and CNR were significantly greater in Group B than in Group A (p ≤ 0.015). Image noise was significantly lower in Group B (p ≤ 0.021), and all subjective image quality indicators, except for delineation of vein contours, were significantly better in Group B (p ≤ 0.021). Mean reconstruction time was significantly shorter in Group B than in Group A (1 min 43 s vs. 131 min 1 s; p < 0.001). Clinical information and radiation dose were not significantly different between the two groups. CONCLUSION: CT venography using ASIR-V at 70 kVp was better than MBIR at 80 kVp in terms of image quality and reconstruction time at similar radiation doses.


Subject(s)
Female , Humans , Image Enhancement , Image Processing, Computer-Assisted , Lower Extremity , Male , Noise , Phlebography , Popliteal Vein , Retrospective Studies , Signal-To-Noise Ratio , Veins , Vena Cava, Inferior , Venous Thrombosis
SELECTION OF CITATIONS
SEARCH DETAIL