Diagnostic Ultrasound Equipment Research Articles

Progress in the Application of Portable Ultrasound Combined with Artificial Intelligence in Pre-Hospital Emergency and Disaster Sites

With the miniaturization of ultrasound and the development of artificial intelligence, its application in disaster scenes and pre-hospital emergency care has become more and more common. This study summarizes the literature on portable ultrasound in pre-hospital emergency and disaster scene treatment in the past decade and reviews the development and application of portable ultrasound. Portable ultrasound diagnostic equipment can be used to diagnose abdominal bleeding, limb fracture, hemopneumothorax, pericardial effusion, etc., based on which trauma can be diagnosed pre-hospital and provide guiding suggestions for the next triage and rescue; in early rescue, portable ultrasound can guide emergency operations, such as tracheal intubation, pericardial cavity puncture, and thoracic and abdominal puncture as well as improve the accuracy and timeliness of operation techniques. In addition, with the development of artificial intelligence (AI), AI-assisted diagnosis can improve the diagnosis level of ultrasound at disaster sites. The portable ultrasound diagnosis system equipped with an AI robotic arm can maximize the pre-screening classification and fast and concise diagnosis and treatment of batch casualties, thus providing a reliable basis for batch casualty classification and evacuation at disaster accident sites.

Deep learning-based classification of adequate sonographic images for self-diagnosing deep vein thrombosis.

Pulmonary thromboembolism is a serious disease that often occurs in disaster victims evacuated to shelters. Deep vein thrombosis is the most common reason for pulmonary thromboembolism, and early prevention is important. Medical technicians often perform ultrasonography as part of mobile medical screenings of disaster victims but reaching all isolated and scattered shelters is difficult. Therefore, deep vein thrombosis medical screening methods that can be easily performed by anyone are needed. The purpose of this study was to develop a method to automatically identify cross-sectional images suitable for deep vein thrombosis diagnosis so disaster victims can self-assess their risk of deep vein thrombosis. Ultrasonographic images of the popliteal vein were acquired in 20 subjects using stationary and portable ultrasound diagnostic equipment. Images were obtained by frame split from video. Images were classified as "Satisfactory," "Moderately satisfactory," and "Unsatisfactory" according to the level of popliteal vein visualization. Fine-tuning and classification were performed using ResNet101, a deep learning model. Acquiring images with portable ultrasound diagnostic equipment resulted in a classification accuracy of 0.76 and an area under the receiver operating characteristic curve of 0.89. Acquiring images with stationary ultrasound diagnostic equipment resulted in a classification accuracy of 0.73 and an area under the receiver operating characteristic curve of 0.88. A method for automatically identifying appropriate diagnostic cross-sectional ultrasonographic images of the popliteal vein was developed. This elemental technology is sufficiently accurate to automatically self-assess the risk of deep vein thrombosis by disaster victims.

Assessing maternal cardiac function by obstetricians: technique and reference ranges

A strong body of evidence has now coalesced indicating that some obstetrical syndromes may result from maladaptive responses of the maternal cardiovascular system. Longitudinal studies have shown that these changes are complex and present before the clinical recognition of preeclampsia and fetal growth restriction, suggesting that hemodynamic maladaptation may play an etiologic role in obstetrical complications. Chronic hypertension is one of the most frequent complications of pregnancy, and recent evidence suggests that control of mild hypertension in early pregnancy improves outcome. The management of chronic hypertension can be improved by understanding specific cardiovascular hemodynamic abnormalities such as increased cardiac output or increased systemic vascular resistance, which can respond to either beta or calcium channel blockers, depending on the hemodynamic findings. Evaluation of maternal cardiac function has not been previously available to obstetrical healthcare providers using diagnostic ultrasound equipment used for fetal evaluation. Obstetrical ultrasound machines may be configured for various probes (endovaginal, abdominal, 3D/4D, and cardiac). This study used a cardiac probe placed in the suprasternal notch to image and measure the descending aorta diameter and the velocity time integral using pulsed and continuous wave Doppler ultrasound in normal pregnant women between 11 and 39 weeks of gestation. These measurements were followed by computation of maternal left ventricular preload, afterload, contractility, and blood flow. This was a prospective cross-sectional study. A total of 400 pregnant women were recruited between 11 and 39 weeks of gestation. Imaging of the maternal aortic arch was performed by placing a cardiac probe in the suprasternal notch to identify the aortic arch using 2D and color Doppler ultrasound. The end-systolic diameter of the aorta was measured at the junction of the left subclavian artery with the descending aorta, which was followed by insonation of the descending aorta to obtain the Doppler waveform. Following insonation of the descending aorta, measurements of the aortic diameter, velocity time integral, ejection time, mean pressure gradient, heart rate, maternal weight and height, and systolic and diastolic blood pressures were entered into an Excel spreadsheet to compute the following: (1) preload measurements of stroke volume, stroke volume index, and stroke work index; (2) afterload measurements of systemic vascular resistance and the potential-to-kinetic energy ratio; (3) contractility measurements of inotropy and the Smith-Madigan inotropy index; and (4) blood flow measurements of cardiac output and the cardiac output index. Fractional polynomial regression analysis was performed for each of the above measurements using gestational age as the independent variable. The diastolic and mean arterial blood pressure decreased from 11 to 18 weeks of gestation and then increased until term. The afterload measurements demonstrated similar characteristics, as all values decreased from 11 weeks until the mid and late second trimester, after which all values increased until term. Changes in contractility demonstrated an increase from 11 weeks to 25 to 28 weeks, followed by a decline until term. Changes in blood flow demonstrated an increase from 11 to 27 weeks and then declined until term. The continuous wave Doppler values were greater than the pulsed Doppler values except for the contractility measurements. Examples of abnormal cardiac measurements were identified in pregnant patients with hypertension and fetal growth restriction. An Excel calculator was created to provide quick computation of z-score measurements and their corresponding centiles described in this study. The technique for evaluation of maternal cardiac function described in this study would allow screening of maternal left ventricular preload, afterload, contractility, and blood flow in the obstetrical clinical milieu once a cardiac probe is acquired for obstetrical ultrasound machines used for fetal evaluation. The above measurements would allow the clinician to select appropriate hypertensive medication on the basis of the results of the evaluation of the maternal left ventricle.

Measurement of the Instantaneous Acoustic Power of Diagnostic Ultrasound Equipment by Piezoelectric-Array Acoustic Power Meter

Measurement of the Instantaneous Acoustic Power of Diagnostic Ultrasound Equipment by Piezoelectric-Array Acoustic Power Meter

Ultrasonography Combined with Blood Biochemistry on the Early Diagnosis of Diabetic Kidney Disease.

Objective Diabetic kidney disease (DKD) has been well recognized as a microvascular complication of diabetes mellitus. Perfusion of intrarenal arteries is closely related with development of DKD. The aim of the present study was to investigate relation of ultrasonography performance of intrarenal arteries and grade of DKD. Methods From May to December at 2021, a total of 54 DKD patients and 36 non-DKD cases were recruited. Ultrasonography performance of intrarenal and arteries at lower extremity was examined by high-resolution ultrasound diagnostic equipment; maximum (Vsmax) as well as minimum (Vdmin) blood velocity of arteries were recorded, and resistance index (RI) of arteries were calculated. Blood routine and biochemical parameters were determined from clinical laboratory of our hospital. Results According to eGFR grading, 42.50% of the 54 DKD cases are at Grade 1, and 18.52%, 11.11%, 9.26%, and 18.52% cases were at Grade 2, 3a, 3b, and 4-5, respectively. Blood urea and creatinine were significantly positively related with progress of DKD, while level of Hb was negatively related with DKD. By ultrasonography; we found that Vsmax and Vdmin of main renal artery (MRA), segmental renal artery (SRA), and interlobular renal artery (IRA) were significantly reduced compared with healthy cases; IR of the above arteries was dramatically elevated, and changes of the above data were more obvious than that of lower extremity. Vdmin of MRA, SRA, and IRA was negatively related with grading of DKD, while RI was positively related with the grading. Converging from RI and level of Hb, we found that the level of Hb is positively related with healthy status of the kidney, while RI of the arteries is negatively with that. Conclusions Resistance index (RI) of intrarenal arteries, obtained from ultrasonography combining with level of hemoglobin (Hb), is the predictor of progress of DKD.

Biosynthetic Gas Vesicles from Halobacteria NRC-1: A Potential Ultrasound Contrast Agent for Tumor Imaging.

Ultrasound contrast agents are valuable for diagnostic imaging and drug delivery. Generally, chemically synthesized microbubbles (MBs) are micro-sized particles. Particle size is a limiting factor for the diagnosis and treatment of many extravascular diseases. Recently, gas vesicles (GVs) from some marine bacteria and archaea have been reported as novel nanoscale contrast agents, showing great potential for biomedical applications. However, most of the GVs reported in the literature show poor contrast imaging capabilities due to their small size, especially for the in vivo condition. In this study, we isolated the rugby-ball-shaped GVs from Halobacteria NRC-1 and characterized their contrast imaging properties in vitro and in vivo. Our results showed that GVs could produce stable and strong ultrasound contrast signals in murine liver tumors using clinical diagnostic ultrasound equipment at the optimized parameters. Interestingly, we found these GVs, after systemic administration, were able to perfuse the ischemic region of a tumor where conventional lipid MBs failed, producing a 6.84-fold stronger contrast signal intensity than MBs. Immunohistochemistry staining assays revealed that the nanoscale GVs, in contrast to the microscale MBs, could penetrate through blood vessels. Thus, our study proved these biosynthesized GVs from Halobacterium NRC-1 are useful for future molecular imaging and image-guided drug delivery.

GLOBAL LOGITUDINAL STRAIN IN HYPERTENSIVE DISORDERS DURING PREGNANCY AS A PREDICTOR FOR EARLY DETECTION OF SUBCLINICAL LEFT VENTRICULAR DYSFUNCTION

Objective: To identify the role of left ventricular (LV) global longitudinal strain (GLS) in the early diagnosis of LV dysfunction among pregnant women with hypertensive disorders. Design and method: Cross-sectional study was conducted at one of the heart centers in Iraq from November 2020 – July 2021, included pregnant women with hypertensive disorder. Echocardiographic data was collected using GE (Vivid E9) diagnostic ultrasound equipment with (M5ScD) MHz transducer. Pregnant women were classified into three groups according to the hypertensive disorders: chronic hypertension (HTN), gestational HTN, and preeclampsia (PE). Results: A 60 pregnant women were enrolled in the study, mean age (32.7 ± 5.8) years, 25% with chronic HTN, 33% with gestational HTN, and 42% with PE. The mean of systolic and diastolic blood pressure were (130.1 ± 10.8) mmHg and (79 ± 7.9) mmHg; respectively, 90% were on medication, and 18% were diabetic. See Table 1. Conclusions: Echocardiography is a valuable tool in diagnosis of LV hypertrophy and diastolic dysfunction in all types of hypertensive disorders during pregnancy. Subclinical cardiac dysfunction in pregnancy related hypertension and preeclampsia can be early detected by impaired GLS.

Sequential Changes in Posterior Shoulder Muscle Elasticity After Throwing as Assessed via Ultrasound Shear Wave Elastography.

Background:Improvements in ultrasound diagnostic equipment and techniques can enable muscle stiffness to be measured quantitatively as muscle elasticity using ultrasound shear wave elastography (USWE), where high muscle elasticity values represent muscle stiffness.Purpose:To use USWE to analyze the sequential changes in muscle elasticity in the posterior shoulder before and after pitching.Study Design:Descriptive laboratory study.Methods:The authors evaluated 14 baseball players who had played in high school or college at an intermediate level. The elasticity of the supraspinatus, infraspinatus (ISP), middle trapezius, lower trapezius (LT), rhomboideus, and serratus anterior muscles of the throwing shoulder was measured using USWE at 3 time points: before, immediately after, and 24 hours after a throwing session of 100 pitches. The authors analyzed the sequential changes in the mean elasticity values of the respective muscles at the 3 time points.Results:The mean elasticity values before, immediately after, and 24 hours after throwing were as follows: supraspinatus: 32.9, 53.4, 43.8 kPa; ISP: 22.7, 44.8, 43.7 kPa; middle trapezius: 45.1, 70.3, 59.9 kPa; LT: 32.8, 45.5, 46.5 kPa; rhomboideus: 29.1, 47.5, 38.8 kPa; and serratus anterior: 19.2, 36.9, 26.5 kPa, respectively. The mean elasticity values for all tested muscles were significantly higher immediately after throwing compared with before throwing (P ≤ .0086 for all), and elasticity values in the ISP and LT remained significantly higher 24 hours after throwing compared with before throwing (P ≤ .019 for both).Conclusion:The study results indicated that pitching significantly increased ISP and LT muscle elasticity even after 24 hours.

ДІАГНОСТИЧНА СОНОГРАФІЯ ПРИ АБДОМІНАЛЬНІЙ ХІРУРГІЇ У ТВАРИН

У статті представлені матеріали щодо історії розвитку ультрасонографії у ветеринарній практиці, наведений аналіз літератури щодо дослідження печінки, селезінки та підшлункової залози, вказуються перспективи методики дослідження в майбутньому. Ультрасонографія черевної поро-жнини у тварин вперше застосовувалась переважно для діагностики вагітності. На сьогодні зазначена методика є важливою діагностичною технікою у ветеринарній медицині, яка застосовуєтьсядля вивчення більшості нормальних та патологічно змінених структур у тварини, забезпечуючишвидкий, неінвазивний спосіб доповнення інформації, отриманої в результаті клінічного обстеженнята рентгенографії. Ультразвукове дослідження засноване на принципі ехолокації, хвилі, що посила-ються датчиком, проходять крізь тканини організму, відображаються та розшифровуються апа-ратом і перетворюються в зображення, яке дає змогу фахівцю ветеринарної медицини оцінитистан внутрішніх органів, тканин і порожнин. Зі збільшенням застосування ветеринарними лікарямиультрасонографічних досліджень у практиці стає зрозуміло, що УЗД є ц інним з асобом в иявленняураження органів черевної порожнини. Оцінка печінки є однією з головних переваг застосування уль-трасонографії черевної порожнини у тварини. Показання включають гепатомегалію, жовтяницю,асцит, підозру на розрив діафрагми, втрату ваги та можливі метастази в печінку. На сьогодні удо-сконалюються та доповнюються методи сонографічних досліджень. Подальше впровадження упрактику та поглиблене вивчення патологій в зазначеній ділянці за допомогою ультрасонографіїдасть змогу об’єктивно встановити стан черевної порожнини та її органів у тварини і оцінититяжкість перебігу хвороби. Впровадження високоякісних, портативних діагностичних ультразвуко-вих апаратів продовжили цей розвиток і попит на ультрасонографію, зважаючи на його діагности-чну цінність, продовжує зростати. Проведений аналіз літератури та доступних інтернет-джерелдав нам змогу оцінити сучасний стан розвитку сонографії у ветеринарній практиці та перспективиподальшого розвитку діагностики стану печінки, селезінки та підшлункової залози, вказати сферипотенційного розвитку методики в майбутньому.

Acoustic impedance measurement of tissue mimicking materials by using scanning acoustic microscopy

Tissue-mimicking materials (TMMs) play a key role in the quality assurance of ultrasound diagnostic equipment and should have acoustic properties similar to human tissues. We propose a method to quantify the acoustic properties of TMM samples through the use of an 80 MHz Scanning Acoustic Microscopy (SAM), which provides micrometer resolution and fast data recording. We produced breast TMM samples in varying compositions that resulted in acoustic impedance values in the range of 1.373 ± 0.031 and 1.707 ± 0.036 MRayl. Additionally, liver TMM and blood mimicking fluid (BMF) samples were prepared that had acoustic impedance values of 1.693 ± 0.085 MRayl and 1.624 ± 0.006 MRayl, respectively. The characterization of the TMMs by SAM may provide reproducible and uniform acoustic reference data for tissue substitutes in a single-run microscopy experiment.

The Effect on Muscle Hardness of Acupuncture Stimulation Using Low-reactive Level Laser Therapy and Silver Spike Point Therapy, along with Stretching.

Muscle hardness causes lower activity in athletic practice or sport competition. Increase in muscle hardness often cause injury and muscle fatigue. The aim of this study is to investigate the effect on muscle hardness of acupuncture stimulation using low-reactive level laser therapy (LLLT) and silver spike point (SSP) therapy, along with stimulation by stretching. Muscle fatigue was created experimentally, and the effect of LLLT was examined with the indices of muscle hardness and the pennation angle, using ultrasound diagnostic equipment with real-time tissue elastography (RTE) functionality. As a result, a combined use of stretching and SSP therapy was effective on muscle hardness, while LLLT alone had no immediate lowering of muscle hardness. In addition, only the laser stretching group demonstrated a significant decrease in the pennation angle. This is because an improved local blood flow due to SSP therapy is considered to have relaxed muscle tonus, which boosted metabolism and removed algogenic substances. This became more effective through a combined use of stretching and low-power laser irradiation. Moreover, it was suggested that stimulation of the acupuncture points in the crus could have a further effect on muscle hardness and the pennation angle.

Preparation and ferroelectric domain structure of micro-scale piezoelectric array fabricated by Mn doped Pb(In<sub>1/2</sub>Nb<sub>1/2</sub>)O<sub>3</sub>-Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>-PbTiO<sub>3 </sub>single crystal

Relaxor ferroelectric single crystal piezoelectric materials have become the core components of new piezoelectric devices such as ultrasonic transducers used in high-end medical ultrasound diagnostic and therapeutic equipment. High-element density array technology and micro-electro-mechanical systems have developed rapidly. For the new generation of 20–80 MHz medical high-frequency ultrasound transducers, the thickness of high-frequency piezoelectric composite material is usually 20–60 μm, and the width of each piezoelectric column is about 5–15 μm. However, the kerf of traditional cutting-and-filling method is too wide, and it is difficult to reduce the size of the array element, which is not conducive to the density of the array element and the demand for higher frequency applications with higher resolution. In this work, a micromechanical fabrication method based on deep reactive ion etching is used to reduce the slit width and increase the array density. We study the fabrication technology of novel and high-performance relaxor ferroelectric single crystal Mn doped Pb(In<sub>1/2</sub>Nb<sub>1/2</sub>)O<sub>3</sub>-Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>-PbTiO<sub>3</sub> (Mn-PIMNT) micro scale piezoelectric array. The influence of the parameters of lithography and deep reactive ion etching on the morphology of piezoelectric array are studied. We obtain the formation mechanisms of different kerfs, different shapes of piezoelectric array element and the relationship among etching rate of Mn-PIMNT single crystal with antenna power, bias power and etching gas ratio. Finally, the size of piezoelectric array element is less than 10 μm, the etching depth is more than 20 μm, the kerf width is less than 5 μm, the angle is controllable, and the maximum is more than 87°. The ferroelectric domain structure and the regulation of electric field effect of micro scale piezoelectric elements are studied by means of piezoelectric force microscope. The variation rules of piezoelectric properties and micro scale are obtained. This method can effectively bypass the shortcomings of the wide kerf and the destruction of the crystal orientation by the traditional cutting-and-filling method. It provides a new preparation technology for the development of high-frequency piezoelectric composites, high-density ultrasonic transducer arrays and new piezoelectric micro mechanical systems. This project presents the guidance and reference for the new micromachining technology of ferroelectric materials, and also lays the foundation for the high-frequency piezoelectric composite and high-frequency ultrasonic transducer.

Research on Quality Evaluation System of Ultrasound Diagnostic Equipment Maintenance

In order to improve the quality of medical equipment after-sales service quality and improve the quality of medical equipment maintenance, this paper discusses the establishment of an evaluation index system to evaluate the quality of ultrasonic diagnostic equipment. From the three aspects of maintenance results, maintenance process and maintenance coverage, the quality of the post-maintenance quality of hospital ultrasound diagnostic equipment manufacturers is objectively evaluated.

MODIFIED GEOMETRICAL METHOD OF HUMAN BLOOD FLOW PARAMETERS DETERMINATION BY DOPLER ULTRASOUND DIAGNOSTICS

The results of the development of a modified geometric method for ultrasound Doppler study of human vessels have been presented. Numerical modeling of the Doppler signal spectrum and testing, as well as experimental testing of the modified geometric method, have been realized, which convincingly proved the advantages of the developed method to the already existing ones.To date, the scope of ultrasound medical diagnostic equipment is constantly expanding. At the same time, ultrasonic techniques do not replace traditional diagnostic methods, but only refine and complement them.Modern complex diagnostics of vascular diseases is based on the common use of radiation methods and ultrasound diagnostics. However, ultrasound Doppler blood flow in the arteries occupies a leading position as the most mobile method of dynamic monitoring and monitoring of blood supply to patients.Interest in the application of ultrasound in medicine is due to the possibility of active action on living tissue, as well as the information acquisition about the tissues themselves.Echography allows you to get information not only about all organs of the human body, but also about their functions, to visualize many pathological processes and their formation in the body. Ultrasonic methods are very informative means for studying the structure of biological tissues and the physiological processes occurring in them.Unfortunately, the current situation in the field of vascular diagnostics is such that existing Doppler methods for finding the maximum spectrum frequency, some of which have been described above, do not take into account the influence of these effects, which leads to incorrect results: errors in determining the maximum frequency of the spectrum lead to a large error in calculation of diagnostic indices, and the result of this is an incorrect making out of the diagnosis. In this regard, the development of the acoustic Doppler-study method of human blood flow parameters is important and timely.

Discussion of the quality control and performance testing of ultrasound diagnostic equipment

In recent years, with the rapid development of ultrasonography, the application and popularization of new technology used in ultrasound equipment, the level of providing diagnostic information for doctors enhances unceasingly, which has become the indispensable diagnostic tool for medical institutions. The performance of equipment is directly related to the doctor’s diagnosis and the patient’s health, therefore, it is very important to choose a good method for quality control and performance testing.

Noninvasive diagnostic of Pulmonary hypertension

In recent years various diseases exist in the world. In this study, we target at Pulmonary Hypertension that is known as the intractable disease. The treatment at appropriate timing is particularly essential to the intractable disease. At present, blood flow velocity and blood pressure are measured using an invasive catheter and the phase difference between them is measured to calculate pulmonary artery occlusion degree. However, in recent years noninvasive diagnosis is considered desirable. Therefore, in this research, we will conduct a study to propose a noninvasive diagnostic method using ultrasound diagnostic imaging equipment. Measure blood flow velocity and blood vessel outer diameter using ultrasonic waves. It was confirmed that the phase angle differs according to the degree of vascular occlusion by comparison of simulation results, experimental results using silicone tubes, and clinical data.

Artifacts in Diagnostic Medical Ultrasound, Volume 1, Greyscale Artifacts (paperback)MartinNecas RRP: AU$79.00 ISBN‐13: 978‐0987292162 Publisher: High Frequency Publishing190 pages

This book is a comprehensive review of the full range of artifacts encountered in the usual practice of diagnostic ultrasound. It includes an account of acoustic artifacts (relating to the interaction of the ultrasound pulses with body tissues), as well as the misleading appearances that sometimes occur because of control settings applied by the operator (TGC, multiple focal zones, dynamic range, frame rate, spatial compounding, harmonics and others). One of its many strengths is that it describes the causes of the artifacts/appearances and includes mention of ways to avoid or eliminate those that are unhelpful or undesirable. The book is divided into thirteen chapters, with more than 230 images and explanatory diagrams, including colour images. Examples of everyday life optical equivalents of the phenomena causing the ultrasound appearances are shown and allow a better understanding of the mechanisms at play. The ultrasound images have reproduced well, with relevant features easily seen, often indicated by arrows or superimposed lines. The explanations of the origin of various artifacts are concise, without excessive technical detail. Examples are presented from a wide range of ultrasound applications, including abdominal, obstetric, vascular and musculoskeletal specialties. Examples of the same artifact, as it appears in images from different applications, are given. For this reason, the book is useful for anyone using diagnostic ultrasound equipment. Scanning tips, such as the need for orthogonal views to explain some appearances, are given throughout the book. Basic principles of transducers and beam formation are mentioned in the context of their effect on image quality, leading to an understanding of why and when to use a stand-off pad, or which transducer to select for a given application. Mention is made of the need for constant critical analysis of images to differentiate between echoes representing artifact and those representing pathology. A good example from abdominal sonography is the non-recognition of lung pathology because the echoes are mistaken as mirror images of liver or spleen, the most common cause of echoes above the diaphragm. A minor criticism can be made about the description of the phenomenon of anisotropy, described in the chapter on attenuation effects and also under refraction effects. The variation in brightness of echoes in a structure such as a tendon is ascribed to refraction effects, but is mainly due to the reduced return of echo signal to the transducer as the angle of approach to the fibrils varies from ninety degrees. Nevertheless, the need for caution and careful technique when scanning anisotropic structures is clearly conveyed. This book is a very useful and practical read for all who are using diagnostic equipment, regardless of background or the specialty of application. Anyone who reads and applies the advice in this publication should have a much better understanding of diagnostic ultrasound artifacts and is unlikely to make errors in diagnosis because of their misleading appearances. It should be in every department's library and read on a regular basis.

Uncertainty evaluation of dead zone of diagnostic ultrasound equipment

This paper presents a model for evaluating measurement uncertainty of a feature used in the assessment of ultrasound images: dead zone. The dead zone was measured by two technicians of the INMETRO's Laboratory of Ultrasound using a phantom and following the standard IEC/TS 61390. The uncertainty model was proposed based on the Guide to the Expression of Uncertainty in Measurement. For the tested equipment, results indicate a dead zone of 1.01 mm, and based on the proposed model, the expanded uncertainty was 0.17 mm. The proposed uncertainty model contributes as a novel way for metrological evaluation of diagnostic imaging by ultrasound.

Conditionally Increased Acoustic Pressures in Nonfetal Diagnostic Ultrasound Examinations Without Contrast Agents: A Preliminary Assessment.

The mechanical index (MI) has been used by the US Food and Drug Administration (FDA) since 1992 for regulatory decisions regarding the acoustic output of diagnostic ultrasound equipment. Its formula is based on predictions of acoustic cavitation under specific conditions. Since its implementation over 2 decades ago, new imaging modes have been developed that employ unique beam sequences exploiting higher-order acoustic phenomena, and, concurrently, studies of the bioeffects of ultrasound under a range of imaging scenarios have been conducted. In 2012, the American Institute of Ultrasound in Medicine Technical Standards Committee convened a working group of its Output Standards Subcommittee to examine and report on the potential risks and benefits of the use of conditionally increased acoustic pressures (CIP) under specific diagnostic imaging scenarios. The term "conditionally" is included to indicate that CIP would be considered on a per-patient basis for the duration required to obtain the necessary diagnostic information. This document is a result of that effort. In summary, a fundamental assumption in the MI calculation is the presence of a preexisting gas body. For tissues not known to contain preexisting gas bodies, based on theoretical predications and experimentally reported cavitation thresholds, we find this assumption to be invalid. We thus conclude that exceeding the recommended maximum MI level given in the FDA guidance could be warranted without concern for increased risk of cavitation in these tissues. However, there is limited literature assessing the potential clinical benefit of exceeding the MI guidelines in these tissues. The report proposes a 3-tiered approach for CIP that follows the model for employing elevated output in magnetic resonance imaging and concludes with summary recommendations to facilitate Institutional Review Board (IRB)-monitored clinical studies investigating CIP in specific tissues.

Analysis of cooling effect by blood vessel on temperature rise due to ultrasound radiation in tissue phantom

Ultrasound diagnostic equipment using ultrasound pulse–echo techniques is considered minimally invasive and highly versatile. However, one of the causes of damage due to ultrasound radiation is temperature rise caused by the absorption of sound energy. Therefore, it is very important to estimate the temperature rise caused by the radiation of ultrasound. Sound intensity in a medium is analyzed by the finite-difference time-domain (FDTD) method, and the temperature distribution caused by sound is estimated by the heat conduction equation (HCE) method in this study. Because blood vessels keep the temperature constant in tissues, the cooling effect of blood flow has to be taken into account for the precise estimation of temperature rise in human tissues. In general, it is well known that capillary vessels are mainly responsible for the cooling effect in tissues and their effect can be estimated as a function of bloodstream ratio. In this paper, a preliminary study on the cooling effect by a large vessel is described for the precise estimation of temperature rise. Blood flow in blood vessels is analyzed using the Navier–Stokes equation. To confirm the precision of the numerical analysis, the results of the numerical analysis are compared with the experimental results using a soft tissue phantom.