17 research outputs found

    Super-resolution ultrawideband ultrasound imaging using focused frequency time reversal music

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    We propose a super-resolution image reconstruction method which uses focused frequency time reversal (FFTR) matrices to focus in frequency for ultrawideband (UWB) ultrasound signals, as well as time reversal MUltiple SIgnal Classification (MUSIC) algorithm to focus spatially on the target location. Our combined method, which we refer to as FFTR-MUSIC, is motivated by the pressing need to improve the resolution of diagnostic ultrasound systems. Compared with the TR matched filter (TRMF) and incoherent TR-MUSIC approaches, our proposed method has lower computational complexity, higher visibility, higher robustness against noise, and higher accuracy for imaging point targets when the targets are closely located. Our simulation results show that under mild speckle and noise conditions, the FFTR-MUSIC can resolve objects less than 200 μm

    Wave atom based Compressive Sensing and adaptive beamforming in ultrasound imaging

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    The paper investigates combining Compressive Sensing (CS) with the robust Capon beamformer (RCB) for the purpose of medical ultrasound image formation with a much reduced number of samples compared to those used in current state-of-art ultrasound. The proposed CS algorithm uses wave atom dictionary as a low dimension projection, a Bernouli random matrix as a sensing matrix and a regularized-l1 optimization technique for recovery. The reconstructed signals are then pre-processed before using the RCB technique augmented with spatial smoothing and diagonal loading. This approach is demonstrated through simulations, wire phantom and in vivo cardiac data with a reduction of up to 1/8 in the processed data rate and ultrasound images of similar perceived quality

    Structurally random fourier domain compressive sampling and frequency domain beamforming for ultrasound imaging

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    Advances in ultrasound technology have fueled the emergence of Point-Of-Care Ultrasound (PoCU) imaging, including improved ease-of-use, superior image quality, and lower cost ultrasound. One of the approaches that can make the adoption of PoCU universal is to make the data acquisition module as simple as a "stethoscope" while further processing and image construction can be done using cloud-based processors. Toward this goal, we use Structurally Random Matrices (SRM) for compressive sensing of ultrasound data, Fourier sparsifying matrix for recovery in 1D, and frequency domain approach for 2D ultrasound image reconstruction. This approach is demonstrated through wire phantom and in vivo carotid arteries data from ultrasound system using 25%, 12.5%, and 6.25% of the full data rate and ultrasound images of similar perceived quality quantified by Structural Similarity Index Metric (SSIM).The authors would like to thank the Canadian funding agencies, OCE VIP I (22984) and NSERC Engage Grant (485353 2015)

    Effect of vitamin D therapy on endothelial function in ischemic heart disease female patients with vitamin D deficiency or insufficiency: A primary report

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    BACKGROUND: Vitamin D deficiency is associated with vascular endothelial dysfunction. We evaluated endothelial function in ischemic heart disease (IHD) patients with vitamin D deficiency or insufficiency before and after vitamin D therapy. METHODS: An uncontrolled before-after study was conducted in Isfahan, Iran on consecutive sample of female IHD patients who had undergone percutaneous coronary intervention in the preceding 6 months and/or referred with chronic stable angina. Forty patients with vitamin D deficiency or insufficiency (serum 25-hydroxy vitamin D &lt; 20 or 20-30 ng/ml, respectively) were included and received two intramuscular injections of 300,000 IU cholecalciferol with 1 month interval. Endothelial function, assessed by measuring flow-mediated dilatation (FMD), and serum 25-hydroxy vitamin D level were measured at baseline and 1 month after the second dose of cholecalciferol. RESULTS: A total of 30 patients completed the study, age = 59.4 &plusmn; 8.7 years; serum 25-hydroxy vitamin D = 19.0 &plusmn; 6.5 ng/ml. After treatment, serum 25-hydroxy vitamin D was reached to &gt; 30 ng/ml in all patients. Brachial artery diameter (mm) after ischemia increased significantly, statistically but not clinically (4.55 &plusmn; 0.37 to 4.67 &plusmn; 0.38, P &lt; 0.001). Furthermore, FMD (%) was increased from 1.96 &plusmn; 1.65 to 4.65 &plusmn; 1.27 (P &lt; 0.001). The amount of change in FMD was not significantly correlated with serum 25-hydroxy vitamin D (r = 0.038, P = 0.858). CONCLUSION: Endothelial function was improved after vitamin D therapy in IHD patients with low serum vitamin D. Controlled studies with larger sample size are required to confirm if vitamin D therapy has effects on endothelial function. &nbsp;&nbsp;</div

    Quality Assessment of Clinical Education in Mazandaran University of Medical Sciences from the Perspective of Clerkships and Interns in 2019

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    Background and purpose: Acquisition of basic skills and professionalism in medicine depends on the quality and quantity of education in clinical settings. This study aimed at assessing the quality of clinical education in different departments of Mazandaran University of Medical Sciences. Materials and methods: This descriptive study was conducted in medical clerkships and interns (n=175). The participants were selected via census sampling in 2019. Data were collected using a checklist based on clinical education standards of Iran Ministry of Health and Medical Education. Written comments from clerkships and interns on the compliance of morning report training programs, clinical trainings, clinical rounds, grand rounds, journal club, and clinical skills center with clinical training standards were received. Data analysis was performed in SPSS V16. Results: The morning report program and clinical skills center program had the highest (85.1%) and lowest (72.2%) scores in clinical education. We observed significant differences between these scores and the scores for other clinical programs (P>0.05). The quality of all clinical education programs was similar according to men and women. The clerkship and interns had different ideas about the status of all clinical education programs except in the morning report program and the clerkship were more satisfied with clinical education programs. Conclusion: From the students' point of view, the morning report program was of acceptable quality, but the clinical training programs, club journal, grand rounds, and clinical skills center had some drawbacks. Training workshops for clinical professors is recommended to enhance the standards of clinical training programs
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