scholarly journals DMAS Beamforming with Complementary Subset Transmit for Ultrasound Coherence-Based Power Doppler Detection in Multi-Angle Plane-Wave Imaging

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4856
Author(s):  
Che-Chou Shen ◽  
Yen-Chen Chu
Keyword(s):  
Plane Wave ◽  
Power Doppler ◽  
P Value ◽  
Low Resolution ◽  
Ensemble Averaging ◽  
Stationary Tissue ◽  
Wave Imaging ◽  
Acquisition Delay ◽  
Complementary Subset ◽  
Low Resolution Images

Conventional ultrasonic coherent plane-wave (PW) compounding corresponds to Delay-and-Sum (DAS) beamforming of low-resolution images from distinct PW transmit angles. Nonetheless, the trade-off between the level of clutter artifacts and the number of PW transmit angle may compromise the image quality in ultrafast acquisition. Delay-Multiply-and-Sum (DMAS) beamforming in the dimension of PW transmit angle is capable of suppressing clutter interference and is readily compatible with the conventional method. In DMAS, a tunable p value is used to modulate the signal coherence estimated from the low-resolution images to produce the final high-resolution output and does not require huge memory allocation to record all the received channel data in multi-angle PW imaging. In this study, DMAS beamforming is used to construct a novel coherence-based power Doppler detection together with the complementary subset transmit (CST) technique to further reduce the noise level. For p = 2.0 as an example, simulation results indicate that the DMAS beamforming alone can improve the Doppler SNR by 8.2 dB compared to DAS counterpart. Another 6-dB increase in Doppler SNR can be further obtained when the CST technique is combined with DMAS beamforming with sufficient ensemble averaging. The CST technique can also be performed with DAS beamforming, though the improvement in Doppler SNR and CNR is relatively minor. Experimental results also agree with the simulations. Nonetheless, since the DMAS beamforming involves multiplicative operation, clutter filtering in the ensemble direction has to be performed on the low-resolution images before DMAS to remove the stationary tissue without coupling from the flow signal.

scholarly journals Two-Dimensional Spatial Coherence for Ultrasonic DMAS Beamforming in Multi-Angle Plane-Wave Imaging

2019 ◽  
Vol 9 (19) ◽  
pp. 3973 ◽  
Author(s):  
Che-Chou Shen ◽  
Pei-Ying Hsieh
Keyword(s):  
Image Quality ◽  
Plane Wave ◽  
Spatial Coherence ◽  
P Value ◽  
Two Dimensional ◽  
One Dimensional ◽  
Wave Imaging ◽  
Artifact Suppression ◽  
Simulation Results ◽  
Acquisition Delay

Ultrasonic multi-angle plane-wave (PW) coherent compounding relies on delay-and-sum (DAS) beamforming of two-dimensional (2D) echo matrix in both the dimensions PW transmit angle and receiving channel to construct each image pixel. Due to the characteristics of DAS beamforming, PW coherent compounding may suffer from high image clutter when the number of transmit angles is kept low for ultrafast image acquisition. Delay-multiply-and-sum (DMAS) beamforming exploits the spatial coherence of the receiving aperture to suppress clutter interference. Previous attempts to introduce DMAS beamforming into multi-angle PW imaging has been reported but only in either dimension of the 2D echo matrix. In this study, a novel DMAS operation is proposed to extract the 2D spatial coherence of echo matrix for further improvement of image quality. The proposed 2D-DMAS method relies on a flexibly tunable p value to manipulate the signal coherence in the beamforming output. For p = 2.0 as an example, simulation results indicate that 2D-DMAS outperforms other one-dimensional DMAS methods by at least 9.3 dB in terms of ghost-artifact suppression. Experimental results also show that 2D-DMAS provides the highest improvement in lateral resolution by 32% and in image contrast by 15.6 dB relative to conventional 2D-DAS beamforming. Nonetheless, since 2D-DMAS emphasizes signal coherence more than its one-dimensional DMAS counterparts, it suffers from the most elevated speckle variation and the granular pattern in the tissue background.

Caricaturing as a general method to improve poor face recognition: Evidence from low-resolution images, other-race faces, and older adults.

2019 ◽  
Vol 25 (2) ◽  
pp. 256-279 ◽  
Author(s):  
Amy Dawel ◽  
Tsz Ying Wong ◽  
Jodie McMorrow ◽  
Callin Ivanovici ◽  
Xuming He ◽  
...  
Keyword(s):  
Older Adults ◽  
Face Recognition ◽  
Low Resolution ◽  
General Method ◽  
Low Resolution Images

scholarly journals POS0548 OPTIMAL ASSESSMENT OF THE RHEUMATOID ARTHRITIS ANKLE AND HINDFOOT: A COMPARATIVE STUDY BETWEEN CLINICAL EXAMINATION AND ULTRASONOGRAPHY

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 508.2-509
Author(s):  
K. Maatallah ◽  
H. Boussaa ◽  
H. Riahi ◽  
H. Ferjani ◽  
M. Habechi ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Clinical Examination ◽  
Demographic Data ◽  
Power Doppler ◽  
Cross Sectional Study ◽  
P Value ◽  
Cross Sectional ◽  
Therapeutic Decisions ◽  
The Mean ◽  
Foot Disease

Background:Foot disease is a common problem in rheumatoid arthritis (RA). Therapeutic decisions are often based on clinical examination (CE) alone, which can be adversely affected by factors such as deformity, obesity, and peripheral edema. Ultrasonography (US) has previously been shown to be more sensitive than CE for detecting synovitis and tenosynovitis in RA forefeet, but few data exist for the hindfoot and ankle.Objectives:The aim of this study was to compare CE and US for the detection of hindfoot and ankle synovitis and tenosynovitis in patients with established RA.Methods:We conducted a cross-sectional study including patients with RA (ACR/EULAR 2010). Demographic data and disease parameters were collected. CE was performed by a rheumatologist for the presence or absence of tenderness, swelling, and mobility restriction of both ankles. The following tendons were examined for tenosynovitis: tibialis anterior (TA) and posterior (TP), fibularis longus (FL), and brevis (FB) (assessed together). In a second time, US examination of the tibiotalar, talonavicular, and subtalar joints and the same tendons as CE was performed by a blinded radiologist experienced in musculoskeletal imaging using a Philips HD11 device with a high-frequency linear transducer. The presence or absence of synovitis and tenosynovitis was recorded, and the composite synovitis score (power doppler / grayscale ultrasound (PDUS)) was measured for each joint. The US score of each patient was defined by the sum of the composite scores of the joints studied (0-30). A p-value <0.05 was considered significant.Results:Sixty-two feet were examined in 31 RA patients (25 women and six men) with a mean age of 54.8±10.8 years old [32-70]. The mean disease duration was 8.5±7.2 years [1-37]. Rheumatoid Factor (RF) and Anti-Citrullinated Peptides Antibodies (ACPA) were positive in 61.3% and 83.8% of cases. The mean DAS28 ESR was 3.8±1.5 [0.6-7].Clinical examination of ankles revealed tenderness in 57.4% of cases, swelling in 38.8% of cases, and restriction in the range of motion in 11.1% of cases. TA tenosynovitis was noted in 14.8% of cases, TP tenosynovitis in 22.2% of cases, and FL and FB tenosynovitis in 31.5% of cases.US showed tibiotalar synovitis in 59.3% of cases, talonavicular synovitis in 64.8% of cases, and subtalar synovitis in 46.3% of cases. TA tenosynovitis was noted in 5.6% of cases, TP tenosynovitis in 22.2% of cases, and FB and FL tenosynovitis in 25% and 11.1% of cases respectively.An association was found between clinical tenderness and US synovitis of the tibiotalar joint (p=0.013) and the talonavicular joint (p=0.027). No association was noted between clinical swelling and US synovitis in these joints.No association was noted between clinical and US tenosynovitis of TA (p=0.279), TP (p=0.436), FB (p=0.495) and FL (p=0.315).Conclusion:Clinical examination of RA ankles may be challenging and needs to be coupled with US, which is more sensitive and accurate in the detection of synovitis and tenosynovitis.Disclosure of Interests:None declared

scholarly journals Plane Wave Imaging through Interfaces

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 4967
Author(s):  
Guillermo Cosarinsky ◽  
Jorge F. Cruza ◽  
Jorge Camacho
Keyword(s):  
Image Quality ◽  
Plane Wave ◽  
Phased Array ◽  
Mathematical Formulation ◽  
Non Destructive Testing ◽  
Arbitrary Geometry ◽  
Destructive Testing ◽  
Wave Imaging ◽  
Imaging Strategy ◽  
Non Destructive

Plane Wave Imaging (PWI) has been recently proposed for fast ultrasound inspections in the Non-Destructive-Testing (NDT) field. By using a single (or a reduced number) of plane wave emissions and parallel beamforming in reception, frame rates of hundreds to thousands of images per second can be achieved without significant image quality losses with regard to the Total Focusing Method (TFM) or Phased Array (PA). This work addresses the problem of applying PWI in the presence of arbitrarily shaped interfaces, which is a common problem in NDT. First, the mathematical formulation for generating a plane wave inside a component of arbitrary geometry is given, and the characteristics of the resultant acoustic field are analyzed by simulation, showing plane wavefronts with non-uniform amplitude. Then, an imaging strategy is proposed, accounting for this amplitude effect. Finally, the proposed method is experimentally validated, and its application limits are discussed.

scholarly journals Micro Non-Uniform Linear Array (MNULA) for Ultrasound Plane Wave Imaging

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 640
Author(s):  
Yujia Tang ◽  
Zhangjian Li ◽  
Yaoyao Cui ◽  
Chen Yang ◽  
Jiabing Lv ◽  
...  
Keyword(s):  
Plane Wave ◽  
Linear Array ◽  
Near Field ◽  
Uniform Linear Array ◽  
Imaging Technology ◽  
Linear Arrays ◽  
Imaging Quality ◽  
Imaging Results ◽  
Wave Imaging ◽  
Laboratory Technology

Ultrasound plane wave imaging technology has been applied to more clinical situations than ever before because of its rapid imaging speed and stable imaging quality. Most transducers used in plane wave imaging are linear arrays, but their structures limit the application of plane wave imaging technology in some special clinical situations, especially in the endoscopic environment. In the endoscopic environment, the size of the linear array transducer is strictly miniaturized, and the imaging range is also limited to the near field. Meanwhile, the near field of a micro linear array has serious mutual interferences between elements, which is against the imaging quality of near field. Therefore, we propose a new structure of a micro ultrasound linear array for plane wave imaging. In this paper, a theoretical comparison is given through sound field and imaging simulations. On the basis of primary work and laboratory technology, micro uniform and non-uniform linear arrays were made and experimented with the phantom setting. We selected appropriate evaluation parameters to verify the imaging results. Finally, we concluded that the micro non-uniform linear array eliminated the artifacts better than the micro uniform linear array without the additional use of signal processing methods, especially for target points in the near-field. We believe this study provides a possible solution for plane wave imaging in cramped environments like endoscopy.

scholarly journals Modified Crack Detection of Sewer Conduit with Low-Resolution Images

2021 ◽  
Vol 11 (5) ◽  
pp. 2263
Author(s):  
Byung Jik Son ◽  
Taejun Cho
Keyword(s):  
Image Processing ◽  
Crack Detection ◽  
Threshold Value ◽  
Optimal Threshold ◽  
Optimal Parameters ◽  
Low Resolution ◽  
The Subject ◽  
Low Resolution Images

Imaging devices of less than 300,000 pixels are mostly used for sewage conduit exploration due to the petty nature of the survey industry in Korea. Particularly, devices of less than 100,000 pixels are still widely used, and the environment for image processing is very dim. Since the sewage conduit images covered in this study have a very low resolution (240 × 320 = 76,800 pixels), it is very difficult to detect cracks. Because most of the resolutions of the sewer conduit images are very low in Korea, this problem of low resolution was selected as the subject of this study. Cracks were detected through a total of six steps of improving the crack in Step 2, finding the optimal threshold value in Step 3, and applying an algorithm to detect cracks in Step 5. Cracks were effectively detected by the optimal parameters in Steps 2 and 3 and the user algorithm in Step 5. Despite the very low resolution, the cracked images showed a 96.4% accuracy of detection, and the non-cracked images showed 94.5% accuracy. Moreover, the analysis was excellent in quality. It is believed that the findings of this study can be effectively used for crack detection with low-resolution images.

Ultrafast plane wave imaging: Doppler frequency distribution

2012 ◽  
Author(s):  
Bruno-Felix Osmanski ◽  
Gabriel Montaldo ◽  
Jeremy Bercoff ◽  
Thanasis Loupas ◽  
Mathias Fink ◽  
...  
Keyword(s):  
Plane Wave ◽  
Frequency Distribution ◽  
Doppler Frequency ◽  
Wave Imaging
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