Optimal Algorithm of Full Focus Array Based on Sparse Matrix

Ultrasonic phased array all-focus imaging algorithm has the advantages of high accuracy and full range dynamic focusing, but the existing imaging time-consuming problem limits its practical industrial application. In order to meet the requirements of real-time imaging and clear and distinguishable image defects in all-focus array ultrasound scanning. In this paper, a sparse optimization model of TFM phased array is established. Based on the Fermat principle, the delay time of each element under two layers of media is calculated, and a two-layer media phased array all-focus imaging algorithm is established, using minimal redundancy. The sparse design of the MRLA is carried out, and the all-focus imaging and sparse all-focus imaging experiments of the two-layer medium are carried out, and the influence of the sparse emission array on the defect quantitative accuracy and the calculation efficiency of the all-focus algorithm is discussed. The final optimized sparse array is compared with the sound field beam pattern of the full array, the smallest redundant array, and the genetic algorithm optimized array, and an all-focus scanning environment is established based on the array. Scanning images can not only obtain the maximum amount of information under minimum redundancy, but also have good sidelobe characteristics. At the same time, the array is sparse, which greatly improves the efficiency of all-focus scanning, and provides a certain reference value for the research of all-focus imaging technology.

Raphe Nuclei Echogenicity and Diameter of Third Ventricle in Schizophrenia Measured by Transcranial Sonography

Introduction: Serotonergic system hyperactivity at 5-HT2A receptors on glutamate neurons in the cerebral cortex is one of the pathways that is theoretically linked to psychosis. In addition to neurotransmitter dysfunction, volumetric studies revealed loss of cortical gray matter and ventricular enlargement in patients with schizophrenia, although there is no case-control research on patients with schizophrenia in order to evaluate echogenicity of RN or DTV. To address these issues, the present study assessed midbrain raphe nuclei (RN) as the main source of brain serotonin and diameter of third ventricle (DTV) as an index of atrophy by transcranial sonography (TCS) in a group of patients with schizophrenia. Methods: 30 patients with schizophrenia and 30 controls were assessed by TCS for RN echogenicity and DTV. TCS was done through temporal bone window via a phased-array ultrasound using 2.5 MHz transducer in depth of 14-16 cm. RN echogenicity assessed by a semi-quantitative visual scale and DTV was measured in thalamic plane. Results: 23 patients (76.5%) and 15 (50 %) controls showed hypoechogenicity of RN which was marginally significant (p=0.06). DTV was in average larger in the patient’s group (0.388 cm vs 0.234 cm, p<0.001). Conclusion: Increased DTV in the patients with schizophrenia is consistent with previous neuroimaging findings. However, marginally lower echogenicity of midbrain RN on TCS in schizophrenia is a new finding that supports the serotonin hypothesis of schizophrenia.

Ultrasound mediated study of the electrokinetic effects in biological tissues and phantoms

Traditional ultrasound imaging monitors the backscattering properties of the object being imaged. Many hybrid imaging techniques such as photo-acoustic imaging, electro-acoustic imaging etc. have been developed to enhance the contrast in imaging. The main objective of this study was to monitor the electrically induced mechanical changes (EIMC) in ultrasound phantoms. Changes in time shifting of the signals and amplitude changes were investigated. Images were formed using a linear array ultrasound probe based on the time-delay estimates and the amplitude changes occurring in the tissue/phantom structure. EIMC in phantoms were found to depend on the applied electric field, gelling agent concentration, and salt concentration. The dependence of EIMC on the various parameters can be explained by the stiffness and fixed charge densities (FCD) of the phantoms. Knowledge gained from experimental results and its future extensions might culminate to form a method to image tissues based on their electrokinetic properties.

Ultrasound mediated study of the electrokinetic effects in biological tissues and phantoms

Traditional ultrasound imaging monitors the backscattering properties of the object being imaged. Many hybrid imaging techniques such as photo-acoustic imaging, electro-acoustic imaging etc. have been developed to enhance the contrast in imaging. The main objective of this study was to monitor the electrically induced mechanical changes (EIMC) in ultrasound phantoms. Changes in time shifting of the signals and amplitude changes were investigated. Images were formed using a linear array ultrasound probe based on the time-delay estimates and the amplitude changes occurring in the tissue/phantom structure. EIMC in phantoms were found to depend on the applied electric field, gelling agent concentration, and salt concentration. The dependence of EIMC on the various parameters can be explained by the stiffness and fixed charge densities (FCD) of the phantoms. Knowledge gained from experimental results and its future extensions might culminate to form a method to image tissues based on their electrokinetic properties.

Application Of A Real-time Linear Array Ultrasound System To The Evaluation Of Live Cattle

A real time linear array ultrasound machine was assessed for bias accuracy and precision. A total of 51 heifers, and steers were scanned for fat thickness over the longissimus muscle, the shoulder and rump; for M. longissimus area between the 12th and 13th ribs; and marbling was subjectively evaluated from M. longissimus scans. Ultrasound data were compared with a live judging committee estimates and with carcass values obtained during USDA grading. Data adjusted for live weight were analysed by correlation and regression techniques. Ultrasound estimates of fat thickness were lower (P<.01) than carcass measurements. Shoulder fat thickness estimation was the lowest in precision and accuracy. The residual standard deviations of ultrasound estimates of fat thickness were not (P>.05) influenced by fat thickness and sex. Ultrasound estimates of M. longissimus area were not different (P>.05) from carcass values and were high in precision (RSD: 2.6 to 6.5cm2). The precision and accuracy of data collected by real time linear array ultrasound system indicate a potential for the application of the ultrasound technique to grading of livestock and carcasses.