Type I IFNs promote cancer cell stemness by triggering the epigenetic regulator KDM1B.

Cancer stem cells (CSCs) are a subpopulation of cancer cells endowed with high tumorigenic, chemoresistant and metastatic potential. Nongenetic mechanisms of acquired resistance are increasingly being discovered, but molecular insights into the evolutionary process of CSCs are limited. Here, we show that type I interferons (IFNs-I) function as molecular hubs of resistance during immunogenic chemotherapy, triggering the epigenetic regulator demethylase 1B (KDM1B) to promote an adaptive, yet reversible, transcriptional rewiring of cancer cells towards stemness and immune escape. Accordingly, KDM1B inhibition prevents the appearance of IFN-I-induced CSCs, both in vitro and in vivo. Notably, IFN-I-induced CSCs are heterogeneous in terms of multidrug resistance, plasticity, invasiveness and immunogenicity. Moreover, in breast cancer (BC) patients receiving anthracycline-based chemotherapy, KDM1B positively correlated with CSC signatures. Our study identifies an IFN-I → KDM1B axis as a potent engine of cancer cell reprogramming, supporting KDM1B targeting as an attractive adjunctive to immunogenic drugs to prevent CSC expansion and increase the long-term benefit of therapy.

Experimental and simulation study of harmonic components generated by plane and focused waves.

Although there is increasing interest in the use of plane waves (PW) in high-frame-rate imaging, not much experimental data is available about their behavior in terms of nonlinear propagation. This paper presents a detailed study of fundamental and harmonic components of the ultrasound beam associated to PW transmission from a linear array. Simulations and hydrophone measurements of PW propagation in water were performed and compared to the results obtained for focused waves (FWs) at various levels of peak negative pressure (PNP). Experimental results confirm that, at comparable PNP, the amplitudes of the harmonics reached by PWs are always higher, over extended regions, than those achieved with FW. For example, at MI = 0.2 the PW second harmonic turns out to be 9 dB higher at 25 mm depth (i.e. in the focal region), and 20 dB higher at 40 mm depth. Simulations additionally show that when ultrasound waves propagate through blood or muscle, the situation is in general reversed but, at low MI, the second harmonic amplitude can still be higher in PW than in FW. Furthermore, it is shown that increasing the array aperture size yields higher harmonic growth in PW compared to FW.

Architecture for an Ultrasound Advanced Open Platform With an Arbitrary Number of Independent Channels.

Ultrasound open platforms are programmable and flexible tools for the development and test of novel methods. In most cases, they embed the electronics for the independent control of (maximum) 256 probe elements. However, a higher number of channels is needed for the control of 2-D array probes. This paper presents a system architecture that, through the hardware and software synchronization of multiple ULA-OP 256 scanners, may implement advanced open platforms with an arbitrary number of channels. The proposed solution needs a single personal computer, maintains real-time features, and preserves portability. A prototype demonstrator, composed of two ULA-OP 256 scanners connected to 512 elements of a matrix array, was implemented and tested according to different channel configurations. Experiments performed under MATLAB control confirmed that by doubling the number of elements (from 256 to 512) the signal-to-noise and contrast ratios improve by 9 dB and 3 dB, respectively. Furthermore, as a full 512-channel scanner, the demonstrator can produce real-time B-mode images at 18 Hz, high enough for probe positioning during acquisitions. Also, the demonstrator permitted the implementation of a new high frame rate, bi-plane, triplex modality. All probe elements are excited to simultaneously produce two planar, perpendicular diverging waves. Each scanner independently processes the echoes received by the 256 connected elements to beamform 1300 frames per second. For each insonified plane, good quality morphological (B-mode), qualitative (color flow-), and quantitative (spectral-) Doppler images are finally shown in real-time by a dedicated interface.

Can plasma antioxidants prevent DNA damage in oxidative stress condition induced by growth hormone deficiency? A pilot study.

Adult growth hormone deficiency (GHD), a condition characterized by increased oxidative stress, is related to augmented cardiovascular, metabolic and oncological risk. A case-control observational study has been performed to evaluate DNA oxidative damage analysing the production of thymidine-glycol in lymphocytes and its correlation with plasma antioxidant levels, evaluated as Total Antioxidant Capacity (TAC). GHD was diagnosed using GHRH 50µg iv+arginine 0,5 g/Kg test, with peak GH response <9 µg/L when BMI was <30 kg/m2 or <4 µg/L when BMI was >30 kg/m2. Three groups were identified: total GHD (n = 16), partial GHD (n = 11), and controls (n = 12). Thymidine-glycol, TAC and IGF-1 have been determined respectively in lymphocytes, plasma and serum samples. When considering thymidine-glycol, we found a significant difference between total vs partial GHD and controls. Unexpectedly thymidine-glycol was lower in total GHD, also accompanied with a significant increase in plasmatic TAC. Our results showed that in adult GHD condition, the production of antioxidant species, in response to increased oxidative stress, could exert a protective effect on thymidine-glycol formation, and consequently on DNA intracellular damages. This pilot study could be inserted in the complex scenario of oxidative damage of GHD, a subtle, yet poorly defined condition, worthy of further insights.

Real-Time High Frame Rate Color Flow Mapping System.

Plane wave (PW) transmission (TX) can be profitably used to improve the performance of color flow mapping (CFM) systems by increasing the autocorrelation ensemble length (EL) and/or the frame rate (FR). Although high-end scanners tend to include imaging schemes using PW TX and parallel receive beams, high frame rate (HFR) CFM has been so far experimentally implemented mostly through research platforms that transmit PWs and beamform/process the received channel data off-line. In this article, full real-time implementation of PW CFM with continuous-time clutter filtering and extended FR/EL is reported. The field-programmable gate arrays (FPGAs) and digital signal processors (DSPs) onboard the ULA-OP 256 research scanner were programmed to perform high-speed parallel beamforming and autocorrelation-based CFM processing, respectively. Different strategies were tested, in which the TX of PWs for CFM is either continuous or interleaved with the TX of packets of B-mode pulses. A fourth-order Chebyshev continuous-time high-pass filter with programmable cutoff frequency was implemented and its clutter rejection performance was positively compared with that obtained when operating on packet data. CFM FRs up to 575 were obtained. The possibility of programming the autocorrelation EL up to 64 permitted to detect flow with high sensitivity and accuracy (average relative errors down to 0.4% ± 8.4%). In vivo HFR movies are presented, showing the dynamics of flow in the common carotid artery, which highlight the presence of secondary flow components.

Evaluation of oxidative stress effects on different macromolecules in adult growth hormone deficiency.

Adult growth hormone deficiency (GHD) is being increasingly recognized to cause premature mortality exacerbated by oxidative stress. A case-control observational study has been performed with the primary objective of evaluating new parameters of oxidative stress and macromolecular damage in adult GHD subjects: serum nitrotryptophan; Total Antioxidant Capacity expressed as LAG time; urinary hexanoil-lysine; urinary dityrosine and urinary 8-OH-deoxyguanosine. GHD was diagnosed using Growth Hormone-Releasing Hormone 50µg iv+arginine 0,5 g/Kg test, with a peak GH response <9 µg /L when BMI was <30 kg/m2 or <4 µg/L when BMI was >30 kg/m2. Patients affected by adult GHD were divided into three groups, total GHD (n = 26), partial GHD (n = 25), and controls (n = 29). Total Antioxidant Capacity, metabolic and hormonal parameters have been determined in separate plasma samples; nitrotryptophan in serum samples; hexanoil-lysine, dityrosine, 8-OH-deoxyguanosine in urine samples. Assessment of hexanoil-lysine exhibited a trend to increase in comparing total GHD vs partial and controls, although not significant. Values of 8-OH-deoxyguanosine did not significantly differ among the three groups. Significant lower levels of dityrosine in partial GHD vs total and controls were found. No significant difference in nitrotriptophan serum levels was found, while significantly greater values of Total Antioxidant Capacity were showed in total and partial GHD vs controls. Thus, our result confirm that oxidative stress is increased both in partial and total adult GHD. The lack of compensation by antioxidants in total GHD may be connected to the complications associated to this rare disorder.

The effect of size range on ultrasound-induced translations in microbubble populations.

Microbubble translations driven by ultrasound-induced radiation forces can be beneficial for applications in ultrasound molecular imaging and drug delivery. Here, the effect of size range in microbubble populations on their translations is investigated experimentally and theoretically. The displacements within five distinct size-isolated microbubble populations are driven by a standard ultrasound-imaging probe at frequencies ranging from 3 to 7 MHz, and measured using the multi-gate spectral Doppler approach. Peak microbubble displacements, reaching up to 10 µm per pulse, are found to describe transient phenomena from the resonant proportion of each bubble population. The overall trend of the statistical behavior of the bubble displacements, quantified by the total number of identified displacements, reveals significant differences between the bubble populations as a function of the transmission frequency. A good agreement is found between the experiments and theory that includes a model parameter fit, which is further supported by separate measurements of individual microbubbles to characterize the viscoelasticity of their stabilizing lipid shell. These findings may help to tune the microbubble size distribution and ultrasound transmission parameters to optimize the radiation-force translations. They also demonstrate a simple technique to characterize the microbubble shell viscosity, the fitted model parameter, from freely floating microbubble populations using a standard ultrasound-imaging probe.

Crowd-Based Cognitive Perception of the Physical World: Towards the Internet of Senses.

This paper introduces a possible architecture and discusses the research directions for the realization of the Cognitive Perceptual Internet (CPI), which is enabled by the convergence of wired and wireless communications, traditional sensor networks, mobile crowd-sensing, and machine learning techniques. The CPI concept stems from the fact that mobile devices, such as smartphones and wearables, are becoming an outstanding mean for zero-effort world-sensing and digitalization thanks to their pervasive diffusion and the increasing number of embedded sensors. Data collected by such devices provide unprecedented insights into the physical world that can be inferred through cognitive processes, thus originating a digital sixth sense. In this paper, we describe how the Internet can behave like a sensing brain, thus evolving into the Internet of Senses, with network-based cognitive perception and action capabilities built upon mobile crowd-sensing mechanisms. The new concept of hyper-map is envisioned as an efficient geo-referenced repository of knowledge about the physical world. Such knowledge is acquired and augmented through heterogeneous sensors, multi-user cooperation and distributed learning mechanisms. Furthermore, we indicate the possibility to accommodate proactive sensors, in addition to common reactive sensors such as cameras, antennas, thermometers and inertial measurement units, by exploiting massive antenna arrays at millimeter-waves to enhance mobile terminals perception capabilities as well as the range of new applications. Finally, we distillate some insights about the challenges arising in the realization of the CPI, corroborated by preliminary results, and we depict a futuristic scenario where the proposed Internet of Senses becomes true.

Teenagers with obesity: Long-term results of laparoscopic adjustable gastric banding.

BACKGROUND: Obesity is a rapidly spreading chronic disease worldwide. Long-term results are critical to assess the effectiveness of a bariatric procedure, particularly in young patients who have long life expectancy. METHODS: A retrospective study on adolescents with morbid obesity who underwent Laparoscopic Adjustable Gastric Banding (LAGB) at our institute from 1995 to 2018 was made. Primary endpoints were efficacy, in term of weight loss and comorbidity resolution, occurrence of complications and reoperations. RESULTS: Fifty-nine patients underwent LAGB between 1995 and 2018. Intra- and post-operative mortality was absent. The patients' presence at follow-up at 5, 10 and 15 years was 38/50 (76%), 18/25 (72%) and 5/8 (63%), respectively. At those times the mean excess weight loss percentage was 61.7 ±â€¯29.4, 48.1 ±â€¯50.4 and 55.8 ±â€¯51.2, respectively. Comorbidity resolution rates were 100% for patients with diabetes, 78% for patients with hypertension, 75% for joint pain suffers, 69% for patients with sleep apnea and 57% for patients with anxiety and depression. Total reoperation rate was 30.5%. The band was removed in 8 patients: 3 due to erosions, 3 by patients' choice and 2 conversions to other bariatric procedures. CONCLUSION: LAGB, in combination with the patients' close follow-up performed by an interdisciplinary team, can be an effective long-term surgical treatment for teenagers with morbid obesity. LEVEL OF EVIDENCE: Level IV.

Technical Details and Result of a Minimally Invasive Management of Gastric Band Erosions: a Series of 47 Patients.

INTRODUCTION: Laparoscopic adjustable gastric banding (LAGB) is proven to be a safe and effective treatment option for obesity in the long term. However, in recent decades, LAGB prevalence progressively decreased worldwide principally due to the incidence and the management of the complications. Understanding the optimal management of the complications becomes therefore of primary importance. The aim of this study is to describe a personal technical, laparoscopic solution of band erosion and to analyze outcomes in 47 patients. METHODS: From October 1995 to January 2019, 3697 LAGB were performed at our institution. Since November 2011, an original laparoscopic gastric banding removal technique was introduced. All the bands placed in these patients were Lap-Band AP System (Allergan, Irvin, CA). The data of the patients who underwent gastric band removal because of band erosion were retrieved from a prospectively collected institutional database, and used for the present retrospective evaluation. RESULT: Ninety-four patients (2.5% of the entire casuistic) with eroded band were diagnosed and treated at our institution. Forty-seven patients were treated with the laparoscopic gastric banding removal technique introduced in November 2011. All the operations have been performed laparoscopically with no conversion or intraoperative complications. There were neither major complications nor peri-operative (30 days) mortality. CONCLUSION: Proper preoperative management and a standardized minimally invasive technique could help to cope with erosion, the most frightening complication of LAGB. Understanding the optimal management of complications and safe reoperation techniques can contribute to a rational use of the LAGB, reversing the current declining tendency.

Microbubble Radiation Force-Induced Translation in Plane-Wave Versus Focused Transmission Modes.

Due to the primary radiation force, microbubble displacement has been observed previously in the focal region of single-element and array ultrasound probes. This effect has been harnessed to increase the contact between the microbubbles and targeted endothelium for drug delivery and ultrasound molecular imaging. In this study, microbubble displacements associated with plane-wave (PW) transmission are thoroughly investigated and compared to those obtained in focused-wave (FW) transmission over a range of pulse repetition frequencies, burst lengths (BLs), peak negative pressures, and transmission frequencies. In PW mode, the displacements, depending upon the experimental conditions, are in some cases consistently higher (e.g., by 28%, when the longest BL was used at PRF = 4 kHz), and the axial displacements are spatially more uniform compared to FW mode. Statistical analysis on the measured displacements reveals a slightly different frequency dependence of statistical quantities compared to transient peak microbubble displacements, which may suggest the need to consider the size range within the tested microbubble population.

Laparoscopic adjustable gastric banding on 3566 patients up to 20-year follow-up: Long-term results of a standardized technique.

BACKGROUND: As obesity is a chronic disease, any bariatric procedure should be validated by long-term results. OBJECTIVE: To present our long-term results after laparoscopic adjustable gastric banding over a period of >20 years and to investigate the outcomes in terms of efficacy, complications, and reoperations. SETTING: Private practice, Italy. METHODS: From October 1995 to February 2018, 3566 laparoscopic adjustable gastric banding were performed by a single surgeon. Data were retrieved from a prospectively collected computer database and retrospectively analyzed. Furthermore, patients were stratified according to body mass index and age and results are evaluated for each subgroup. RESULTS: All the operations were performed laparoscopically without any mortality and/or major specific complications. Nine hundred twenty-six patients (71.6%) completed at least 10-years follow-up and 180 (58.4%) reached 15-years follow-up. There was a mean of 49%, 52.6%, and 59.2% of excess weight loss at 10, 15, and 20 years, respectively. Major late complications were pouch herniation-dilation (5.8%) and erosion (2.5%), both solved by a replicable, less invasive operation. Total reoperation rate was 24.1%. CONCLUSION: Our experience suggested that the combination of a standardized surgical technique and close patient follow-up, performed in collaboration with an interdisciplinary team, may make the laparoscopic adjustable gastric banding system a powerful long-term surgical tool in the treatment of morbid obesity. The best results were obtained in young patients with high body mass index but results were also satisfactory in elderly patients and in those with low body mass index.

Circulating irisin levels in heart failure with preserved or reduced ejection fraction: A pilot study.

Irisin, a recently discovered myokine, has been considered a prognostic factor in several cardiovascular diseases. Nevertheless, no data are available on the role of irisin in patients with heart failure (HF), both with preserved (HFpEF) or reduced (HFrEF) ejection fraction. We have therefore evaluated the circulating irisin levels in HFpEF and HFrEF patients, correlating them with metabolic parameters and total antioxidant capacity (TAC), as index of oxidative stress. Irisin was significantly higher in HFpEF than in HFrEF patients (7.72 ± 0.76 vs 2.77 ± 0.77 ng/ml, respectively). An inverse correlation between irisin and TAC was found in HFpEF, but not in HFrEF. Conversely, no correlation was present with HOMA index. These data support the hypothesis that a different pathophysiological mechanism is involved in the two HF subtypes, and oxidative stress modulates irisin secretion.

Real-Time High-Frame-Rate Cardiac B-Mode and Tissue Doppler Imaging Based on Multiline Transmission and Multiline Acquisition.

Cardiovascular diseases, the leading cause of death in the world, are often associated with the dysfunction of the left ventricle. Even if, in clinical practice, the myocardial function is often assessed through visual wall motion scoring on B-mode images, quantitative techniques have been introduced, e.g., ultrasound tissue Doppler imaging (TDI). However, this technique suffers from the limited frame rate of currently available imaging techniques that needs to be balanced with the field of view. High-frame-rate (HFR) cardiac imaging has been recently tested off-line by simultaneously transmitting multiple focused beams into different directions and acquiring raw channel data into a PC. Several image lines were then reconstructed from the echoes of each transmission (TX) event. The same approach has been used to increase the TDI frame rate without restricting the field of view. This paper demonstrates the real-time feasibility of multiline TX and acquisition methods for both HFR cardiac B-mode and TDI. These approaches have been implemented on the ULA-OP 256 research scanner, by taking care that the related resources were optimally exploited for these new applications. The obtainable performance in terms of image quality and frame rate has also been investigated. Experiments performed with a 128-element phased array probe show, for the first time, that real-time B-mode imaging is feasible at up to 1150 Hz without significant reduction in image quality or field of view. The implementation of a real-time TDI algorithm allowed obtaining TDI images with a frame rate of 288 Hz for a 90°-wide field of view. Finally, in vivo examples demonstrate the feasibility and the suitability of the method in clinical studies.

Plane-Wave Contrast Imaging: A Radiation Force Point of View.

Radiation force is known to produce microbubble axial displacements by an amount that depends on the transmit burst frequency, amplitude, and length, as well as the pulse repetition frequency (PRF). In the standard focused-imaging mode, the actual PRF experienced by each microbubble is low, because it is of the order of the frame rate (i.e., usually tens of Hertz). In the plane-wave imaging mode, however, the actual PRF is considerably higher, as it is equivalent to the transmit PRF (kiloHertz range). Furthermore, the radiation pressure is expected to be almost uniform over the field of view, and typically lower than the peak pressure experienced in the focused transmit (TX) mode. We have experimentally investigated the possible effects of radiation force in the plane-wave mode. Here, we report on preliminary findings that show that the acoustic radiation force is negligible only at lower TX levels. At higher TX amplitudes, the bubble displacements due to radiation force are comparable to those obtained for focused waves at the same PRF. In addition, the radiation force is nearly uniform over the field of view and increases as the TX burst central frequency approaches the resonance frequency of size-isolated microbubbles.

Oxidative stress in adult growth hormone deficiency: different plasma antioxidant patterns in comparison with metabolic syndrome.

BACKGROUND AND AIMS: Growth hormone deficiency (GHD) is a condition associated with increased cardiovascular risk and insulin-resistance. Oxidative stress (OS) could be a mechanism underlying both these phenomena. In order to investigate plasma antioxidant defenses in such condition, we evaluated adults with GHD, compared with controls and metabolic syndrome patients (MetS), studying plasma total antioxidant capacity (TAC) and coenzyme Q10 (CoQ10, lipophilic antioxidant) levels, both in its oxidized and reduced forms, correlating this data with metabolic and hormonal pattern. MATERIALS AND METHODS: In this case-control study, 51 GHD, 36 controls, and 35 MetS were enrolled. An evaluation of hormonal and metabolic parameters was performed. TAC was measured using the system metmyoglobin -H202 and the chromogen ABTS, whose radical form is spectroscopically revealed; latency time (LAG) in the appearance of ABTS● is proportional to antioxidant in sample. CoQ10 was assayed by electrochemical method. RESULTS: Despite HOMA index was higher in both GHD and MetS (2.2 ± 0.3 and 3.1 ± 0.3 vs. 1.2 ± 0.2 in controls), only in MetS we observed lower LAG levels (64.5 ± 3.1 s vs. 82.8 ± 5.8 in GHD and 80.6 ± 6.6 in controls), suggesting an increased consumption of antioxidants. LAG significantly correlated with uric acid only in MetS (r 2 = 0.65, p < 0.001), suggesting a different pattern of antioxidants. CoQ10 exhibited a trend toward lower levels in GHD, although not significant. CONCLUSIONS: Our data indicate that GHD, although sharing with MetS various metabolic features, including increased HOMA levels, showed a different pattern of plasma antioxidants, suggesting inadequate reactivity toward radical production rather than an antioxidants consumption as in MetS.

Architecture of an Ultrasound System for Continuous Real-Time High Frame Rate Imaging.

High frame rate (HFR) imaging methods based on the transmission of defocused or plane waves rather than focused beams are increasingly popular. However, the production of HFR images poses severe requirements both in the transmission and the reception sections of ultrasound scanners. In particular, major technical difficulties arise if the images must be continuously produced in real-time, i.e., without any acquisition interruption nor loss of data. This paper presents the implementation of the real-time HFR-compounded imaging application in the ULA-OP 256 research platform. The beamformer sustains an average output sample rate of 470 MSPS. This allows continuously producing coherently compounded images, each of 64 lines by 1280 depths (here corresponding to 15.7 mm width and 45 mm depth, respectively), at frame rates up to 5.3 kHz. Imaging tests addressed to evaluate the achievable speed and quality performance were conducted on phantom. Results obtained by real-time compounding frames obtained with different numbers of steering angles between +7.5° and -7.5° are presented.

Plasmatic and Intracellular Markers of Oxidative Stress in Normal Weight and Obese Patients with Polycystic Ovary Syndrome.

Introduction Insulin resistance (IR) is associated with polycystic ovary syndrome (PCOS). Oxidative stress (OS) is, in turn, related to IR. Studies in PCOS evidenced an increase in OS markers, but they are mainly performed in obese patients, while the complex picture of normal weight PCOS is still poorly investigated. Matherials and Methods To investigate OS in PCOS and relationship with hormonal and metabolic picture, we performed a case-control study in 2 PCOS groups: normal weight (N-PCOS, n=21, age 18-25 ys, mean±SEM BMI 20.7±0.2 kg/m2) and obese (OB-PCOS, n=15, 20-30 ys, BMI 32.8±1.1), compared with control groups matched for BMI: normal (N-C, n=10, 20-30 ys, BMI 21.6±0.9) and obese (OB-C, n=20, 21-31ys, BMI 36.8±1.0). Malondialdehyde (MDA) in blood plasma and peripheral mononuclear cells, obtained by density-gradient centrifugation, was assayed spectrophotometrically by TBARS assay. CoenzymeQ10 (CoQ10) in plasma and cells was assayed by HPLC. Plasma Total Antioxidant Capacity (TAC) was also measured by spectrophotometric method. Results PCOS patients exhibited higher Testosterone levels than controls, but OB-PCOS had highest HOMA (Homeostasis Model Assessment) index, suggesting marked insulin resistance. Despite plasma MDA levels were not significantly different (N-PCOS 3380±346.94 vs. N-C 7 120±541.66; OB-PCOS 5 517.5±853.9 vs. OB. 3 939.66±311.2 pmol/ml), intracellular MDA levels were significantly higher in N-PCOS than controls (mean 3 259±821.5 vs. 458±43.2 pmol/106/cells) and higher than OB-PCOS, although not significantly (1363.1±412.8 pmol/106/cells). Intracellular CoenzymeQ10 was higher in N-PCOS than in N-C, but the highest levels were found in OB-C. Conclusions Our data, while confirming the presence of OS in obese PCOS patients in agreement with literature, suggest that OS could be present also in normal weight PCOS, but it can be revealed in tissue rather than in plasma. The relationship with metabolic status remains to be established, but could be a physiopathological basis for antioxidant treatment in such patients.

Coded Spectral Doppler Imaging: From Simulation to Real-Time Processing.

Transmission of coded pulses and matched receive filtering can improve the ultrasound imaging penetration depth while preserving the axial resolution. This paper shows that the pulse compression technique may be integrated in a low-cost scanner to be profitably used also in spectral Doppler investigations. By operating on beamformed, demodulated, and down-sampled data in the frequency domain, a single digital signal processor is proved sufficient to perform both pulse compression and multigate spectral Doppler algorithms in real time. Simulations, phantom, and in vivo experiments demonstrate that the transmission of (2.5 or [Formula: see text] long) linear frequency-modulated chirps with bandwidths over the range 1.6-5.4 MHz, rather than of corresponding sine-burst pulses, provides signal-to-noise ratio (SNR) improvements very close to theory. Even in the presence of selective tissue attenuation, SNR gains up to 11 and 13.3 dB have been obtained for the short and the longer chirp, respectively. This may be important in clinical Doppler applications where the needed penetration depth is not achieved with sufficient SNR unless very long bursts are transmitted.

ULA-OP 256: A 256-Channel Open Scanner for Development and Real-Time Implementation of New Ultrasound Methods.

Open scanners offer an increasing support to the ultrasound researchers who are involved in the experimental test of novel methods. Each system presents specific performance in terms of number of channels, flexibility, processing power, data storage capability, and overall dimensions. This paper reports the design criteria and hardware/software implementation details of a new 256-channel ultrasound advanced open platform. This system is organized in a modular architecture, including multiple front-end boards, interconnected by a high-speed (80 Gb/s) ring, capable of finely controlling all transmit (TX) and receive (RX) signals. High flexibility and processing power (equivalent to 2500 GFLOP) are guaranteed by the possibility of individually programming multiple digital signal processors and field programmable gate arrays. Eighty GB of on-board memory are available for the storage of prebeamforming, postbeamforming, and baseband data. The use of latest generation devices allowed to integrate all needed electronics in a small size ( 34 cm ×30 cm ×26 cm). The system implements a multiline beamformer that allows obtaining images of 96 lines by 2048 depths at a frame rate of 720 Hz (expandable to 3000 Hz). The multiline beamforming capability is also exploited to implement a real-time vector Doppler scheme in which a single TX and two independent RX apertures are simultaneously used to maintain the analysis over a full pulse repetition frequency range.