High-resolution Transducer Research Articles

"A study to assess the use of ultrasonography in detecting maxillofacial fractures"

Background:-Maxillofacial fractures occur most frequently as an after effect of trauma. Initially during first century, diagnosis of fracture was carried out using conventional radiographs but it has certain shortcomings which includes high radiation exposure, difficulty in detecting hair line & non dislocated fractures due to anatomical superimposition from the para-nasal air sinuses obscuring the visibility of underlying anatomical structures. At the time of this study the literature was focused more about isolated facial fracture and less about complete comprehensive evaluation of maxillofacial fractures using USG. A radiological confirmation is necessary because missed or incorrectly managed cases may encounter serious consequences. The most common causes of these fractures are road traffic accidents. The etiology and incidence of these fractures vary in different countries. The nasal bone being the most prominent bone is often prone to fracture (39% of maxillofacial fractures). The mandible and zygomatico-maxillary complex play an essential role in facial contour and mastication. A fracture in this area can affect facial appearance, function, and quality of life. To restore aesthetics, function, and quality of life, it is essential to completely diagnose these fractures for effective management. Thus we aim to add on more facts to the preexisting context which may further help to utilize ultrasonography as a first line diagnostic tool in detecting various maxillofacial fractures. Materials & Methods:-Thirty four patients who presented with clinical signs & symptoms suggestive of maxillofacial fractures having computed tomography ( GE Revolution 16 slice, 1.25mm slices) & conventional radiographs( GENORAY PAPAYA Plus DP-1S )done as a standard protocol for management of maxillofacial fractures were included in this study. These patients were subjected to ultrasonographic ( VOLUSON 730 PRO )examination using 5-7 MHz frequency linear probe by an experienced sonologist who was blinded to the findings of computed tomography and conventional radiographs. Assessment was carried out in real time. The findings of conventional radiographs & ultrasonography were then correlated with findings on computed tomography. In this study computed tomography was taken as the gold standard & sample size estimation done with “two tailed test’ in EPI INFO SOFTWEAR Results:-The data analysis was performed by diagnostic & sensitivity test. Inferentional statistics was performed using EPI INFO 1.1.1.14. In this study ultrasonography shows sensitivity 86.20%, specificity 100%, positive predictive value (PPV) 100%, negative predictive value (NPV) 20.00%, accuracy of 86.66% in detecting maxillofacial fractures. When correlating the fracture detected by computed tomography & ultrasonography the results were highly significant with P = 0.001893. Conventional radiographs shows sensitivity 50.57%, specificity 66.66%, PPV 97.77%, NPV 4.44%, accuracy of 51.11% in detecting maxillofacial fractures. When correlating fractures detected by USG & CR the results are significant with P = 0.00467. Conclusion:-In the present study ultrasonography has shown better accuracy than conventional radiographs in diagnosing maxillofacial fractures. Though CT scan is the gold standard, we had observed that USG is equal to CT scan in diagnosing most of the superficial fractures. Hence with the availability of well experienced sonologist and high resolution transducer USG can be considered as the first line diagnostic procedure in suspected maxillofacial fractures.

Diverging Polymer Acoustic Lens Design for High-Resolution Row-Column Array Ultrasound Transducers.

Spherical diverging acoustic lenses mounted on flat 2-D row-column-addressed (RCA) ultrasound transducers have shown the potential to extend the field of view (FOV) from a rectilinear to a curvilinear volume region and, thereby, enable 3-D imaging of large organs. Such lenses are usually designed for small aperture low-frequency transducers, which have limited resolution. Moreover, they are made of off-the-shelf pieces of materials, which leaves no room for optimization. We hypothesize that acoustic lenses can be designed to fit high-resolution transducers, and they can be fabricated in a fast, cost-effective, and flexible manner using a combination of 3-D printing and casting or computer numerical control (CNC) machining techniques. These lenses should increase the FOV of the array while preserving the image quality. In this work, such lenses are made in concave, convex, and compound spherical shapes and from thermoplastics and thermosetting polymers. Polymethylpentene (TPX), polystyrene (PS), polypropylene (PP), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), and room-temperature-vulcanizing (RTV) silicone diverging lenses have been fabricated and mounted on a 128 + 128 6-MHz RCA transducer. The performances of the lenses have been assessed and compared in terms of FOV, signal-to-noise ratio (SNR), bandwidth, and potential artifacts. The largest FOV (24.0.) is obtained with a 42.64-mm radius PMMA-RTV compound lens, which maintains a decent fractional bandwidth (53%) and SNR at 6 MHz (.9.1-dB amplitude drop compared with the unlensed transducer). The simple PMMA TPX, PS, PP, PDMS, and RTV lenses provide an FOV of 12.2°, 6.3°, 8.1°, 11.7°, 0.6°, and 10.4°; a fractional bandwidth of 97%, 46%, 103%, 46%, 97%, 53%, and 49%; and an amplitude drop of -5.2, -4.4, -2.8, -15.4, -6.0, and -1.8 dB, respectively. This work demonstrates that thermoplastics are suitable materials for fabricating low-attenuation convex diverging lenses for large-aperture, high-frequency 2-D transducers. This is highly desired to achieve high-resolution volumetric imaging of large organs.

Tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is aphakomatosis and is atumor predisposition syndrome. As agenetic multisystem disease, patients present with a broad range of changes in the brain, heart, skin, kidneys, and lungs. Which imaging modalities are required to monitor TSC patients according to current international recommendations? Common findings in TSC are cortical tubers, subependymal nodules, and giant cell astrocytomas in the central nervous system (CNS), rhabdomyomas in the heart, and cysts and angiomyolipomas in the kidneys. Magnetic resonance imaging (MRI) of the brain and kidneys and abdominal ultrasound are the imaging modalities of choice, due to the very good soft tissue contrast and lack of X‑ray radiation. Using standard and functional MRI sequences in a multimodal approach, the type, malignancy, size, and morphology of changes in TSC can be reliably determined. Abdominal ultrasound using high-resolution transducers can be used to rapidly and reliably detect even the smallest changes in the kidneys. Regular follow-up of patients with TSC using MRI and ultrasound is necessary for early detection of complications, for planning individualized therapy, and for optimal lifelong care.

De Garengeot’s hernia: case report

Introduction: De Garengeot hernia is an entity mainly diagnosed intraoperatively. It is more frequently observed in women and is defined as the presence of the vermiform appendix inside to femoral hernia. Most femoral hernias are identified based on clinical diagnosis, but diagnostic imaging is necessary for confirmation. Ultrasound, for example, is a valuable tool to characterize the anatomy of the hernia and its content, and to establish surgical planning. Case presentation: A 75-year-old woman attended the general surgery department of a high complexity hospital in Bogotá, Colombia, due to a painful mass in the right inguinal region. The initial ultrasound study showed a femoral hernia containing the incarcerated appendix and periappendiceal fluid in the hernial sac. The patient developed chronic appendiceal inflammation, so she underwent femoral hernia repair with mesh and appendectomy without complications, achieving a satisfactory recovery. Conclusion: Clinical examination may be sufficient to confirm the presence of a hernia in a large number of cases when the diagnostic approach involves the search of inguinal masses with pain. However, to facilitate surgical planning, diagnostic imaging, especially ultrasound with high resolution transducers, is the primary tool to characterize the type of hernia and the contents of the hernial sac.

Ultrasonographic Evaluation of Peripheral Nerves: Technical Considerations.

Advances in ultrasonographic (US) technology featuring high-resolution transducers have revolutionized US over recent years as a modality increasingly used in the evaluation of musculoskeletal structures and peripheral nerves. A wide variety of nerve pathologies can be detected, such as neoplastic and tumorlike lesions, entrapment syndromes, posttraumatic injuries, and inflammatory conditions. US can serve as an imaging tool for guiding percutaneous treatments, such as injection therapies or hydrodissection, and assist with perioperative nerve marking and visualization of peripheral nerves in the operating room. This article describes the normal US appearance of peripheral nerves, US imaging techniques, common peripheral nerve pathologies, and interventional applications.

High-resolution pressure transducer design and associated circuitry to build a network-ready smart sensor for distributed measurement in oil and gas production wells

Miniaturized single-mode thickness-shear pressure transducer combined with high-temperature SOI, silicon on insulator, integrated circuit technology is proposed as network-ready high-pressure high-resolution smart sensor for distributed data acquisition in oil and gas production wells. The transducer miniaturization is investigated with a full 3D computer model previously developed by the authors to assess the impact of intrinsic losses and various geometrical features on transducer performance. Over the last decades there has been a trend toward size reduction of high-resolution pressure transducer. The implemented model provides insight into the evolution of high-resolution pressure transducers from Hewlett-Packard™ to Quartzdyne™ and beyond. Distributed measurement in production oil wells in extreme harsh environment, such as found in the pre-salt layer, is an unsolved problem. The industry move toward electrified wells offers an opportunity for application of smart sensor technology and power line communications to achieve distributed high-resolution data acquisition.

The AIUM Practice Parameter for the Performance of an Ultrasound Examination of the Abdomen and/or Retroperitoneum.

The AIUM Practice Parameter for the Performance of an Ultrasound Examination of the Abdomen and/or Retroperitoneum.

Detection and Characterization of Sentinel Lymph Node by Ultrasound Molecular Imaging with B7-H3-Targeted Microbubbles in Orthotopic Breast Cancer Model in Mice.

Accurate identification and assessment of sentinel lymph node (SLN) using noninvasive imaging methods can play a vital role in tumor staging, surgical planning, and prognostic evaluation. In this study, we assessed the efficacy of B7-H3-targeted molecular-ultrasound imaging for the early SLN detection, and characterization in a mouse model of orthotopic breast cancer. We established a mouse breast cancer model with lymph node metastasis by injecting MAD-MB 231 cells which were engineered to express firefly luciferase reporter gene into the fat pad of the right 4th mammary gland in female BALB/c nude mice. The sole lymph node (LN) close to the tumor was regarded as the SLN for imaging investigation, which included metastatic and non-metastatic SLNs. The LN in the right 4th mammary gland from normal mice was used as normal control (normal mice LN). The commercially available preclinical streptavidin-coated, perfluorocarbon-containing lipid-shelled microbubbles (VisualSonics, Toronto, Canada) were used to generate B7-H3-targeted microbubbles (MBB7-H3) and control microbubbles (MBControl). Then, ultrasound molecular imaging (USMI) was performed using a high-resolution transducer (MS250; center frequency, 21MHz; Vevo 2100; VisualSonics, Toronto, Canada) after intravenous injection of microbubbles. The SLN was clearly detected and located under conventional (B-mode) and contrast-enhanced ultrasonography with microbubble injection. The metastatic SLNs showed a markedly higher signal from B7-H3-targeted microbubbles (MBB7-H3) compared to the non-metastatic SLNs and normal LNs. The metastatic SLN was further confirmed by ex vivo bioluminescence imaging and eventually verified by histological analysis. Our findings suggest the potential value of USMI using B7-H3 targeted microbubbles in breast cancer and establish an effective imaging method for the non-invasive detection and characterization of SLN.

Ультразвуковое исследование блуждающих нервов у пациентов с болезнью Паркинсона

Parkinson’s disease (PD) is a neurodegenerative multisystem disorder characterized by pathologic α-synuclein aggregation affecting, among other things, vagal fibers. The aim of this study was to investigate the cross-sectional area (CSA) of the vagus nerve (VN) in patients with PD using ultrasound imaging. The study was conducted in 32 patients with PD (15 men and 17 women; mean age 58 ± 10 years) and 32 healthy controls comparable with the main group in terms of sex and age. All study participants underwent ultrasound examination of the VN using a high-resolution transducer. Left VN CSA was significantly smaller in patients with PD than in the control group (1.78 ± 0.52 mm2 vs 2.11 ± 0.41 mm2; р = 0.007). A similar result was obtained for right VN CSA at the trend level. ROC analysis demonstrated that the threshold CSA value of < 2.10 mm2 for the left VN has low diagnostic sensivity (59%) for VN atrophy in patients with PD. Right VN CSA was significantly larger than left VN CSA in both groups (p < 0.001). The analysis of the PD group did not reveal any associations between VN CSA and age, duration and stage of the disease, motor (UPDRS III) and non-motor (NMSQ) scores. Patients with akinetic-rigid form of PD had smaller left VN CSA than patients with the mixed form of the disease (р < 0.05). A moderate inverse correlation was established between left VN CSA and the area of substantia nigra hyperechogenicity on both sides (р < 0.04); for the right VN a similar correlation was established at the trend level. High-resolution ultrasound of patients with PD demonstrated atrophy of the VN and the association of VN CSA with the clinical form of the disease and the ultrasound features of the substantia nigra.

Ultrasound evaluation of access complications: Thrombosis, aneurysms, pseudoaneurysms and infections.

Arteriovenous fistula (AVF) complications are classified based on fistula outcomes. This review aims to update colour Doppler (CD) and pulse wave Doppler (PWD) roles in managing early and late complications of the native and prosthetic AVF. Vascular access (VA) failure occurs because inflow or outflow stenosis activates Wirchow’s triad inducing thrombosis. Therefore, the diagnosis of the tributary artery and outgoing vein stenosis will be the first topic considered. Post-implantation complications occur from the inability to achieve AVF maturation and dialysis suitability due to inflow/outflow stenosis. Late stenosis is usually a sequence of early defects repaired to maintain patency. Less frequently, in the mature AVF or graft, complications are acquired ‘de novo’. They derive either from incorrect management of vascular access (haematoma, pseudoaneurysm, prosthesis infection) or wall pathologies (aneurysm, myxoid valve degeneration, kinking, coiling, abnormal dilation from defects of elastic structures). High-resolution transducers (10–20 MHz) allow the characterization of the wall damage, haemodynamic dysfunctions, early and late complications even if phlebography remains the gold standard for the diagnosis for its sensitivity and specificity.

Ultrasonographic Detection of Interstitial Nephritis in a Canine Fetus

Background: A detailed ultrasound examination of the fetal urinary tract as part of prenatal care is important to detect possible abnormalities. Early diagnosis can prevent more serious damage such as loss of kidney function. Interstitial nephritis can compromise renal functionality. Also, acute interstitial nephritis is a frequent cause of acute kidney injury and can become chronic if not treated. Besides, a renal biopsy can help in the diagnosis and at the staging of the disease. Therefore, this report aims to describe the ultrasonographic findings of the renal tissues in a canine fetus affected by interstitial nephritis.Case: Gestational ultrasound evaluations were performed in a female Pug, at the 25th, 45th, and 58th gestational days. Ultrasound examination was performed with a 9.0 MHz linear transducer and a high-resolution digital transducer with a frequency standardized at 17.0 MHz. During the first evaluation, embryonic vesicles were detected and were compatible with the gestational period. At 45 days of gestation, some abnormalities were observed in the kidneys of one of the fetuses, such as increased cortical echogenicity, cortical thickening, loss of corticomedullary ratio (1:1), renal pelvis and ureter dilatation by echogenic content. Biparietal and abdominal diameters were also lower than that from the other fetuses, which did not show abnormalities, being compatible with the estimated gestational age. However, the heart rate was similar among all fetuses. On the 58th day, we observed in the underdeveloped fetus that both kidneys still presented the abnormalities seen previously, in addition to the presence of a cystic structure in the right kidney, in the cranial topography of the cortex. The other fetuses kept showing normal ultrasonographic findings, normal heartbeat, all of these compatible with the ultrasound gestational age. The delivery occurred without complications and only the underdeveloped fetus stillborn. Then, it was submitted to a necropsy where chronic interstitial nephritis was found in the histopathological analysis.Discussion: Adequate prenatal care is important to detect abnormalities in fetuses, in which ultrasound examination allows to access fetal development. The gestation in the bitch seemed to be occurring without complications, but the B mode and High Definition ultrasound techniques were able to identify abnormal development of the fetus' kidneys. Both techniques showed to be secure to the fetuses and the mother, as they are non-invasive and free of radiation. These findings, different from those described as normal for a fetus, reinforce the warning signal for a possible establishment of anomalies consistent with nephropathy. Still, histopathology is important to exclude other diseases and help to define prognosis. Interstitial nephritis can significantly affect perinatal survey, considering that the fetus was stillborn, confirming that the description of such anomalies can help to prevent disease. Since nephritis can be associate with the use of some medicines, the orientation of the owner regarding drug use during bitch pregnancy is essential. Therefore, this is the first report describing renal abnormalities in a canine fetus, which highlights the importance of ultrasound examination for disease identification in prenatal care. Lastly, high-resolution ultrasound (HD) could provide detailed information on abnormalities in the fetal kidney.

Association of Echocardiographic Epicardial Fat Thickness and Carotid Intima Media Thickness with the Severity of Coronary Artery Disease

Background: Coronary artery disease remains the main cause of death despite several preventive programs. Epicardial adipose tissue is a visceral fat depot of the heart located along the large coronary arteries and on the surface of ventricles and apex. Intima media thickness is commonly recognized as the initial stage in the development of atherosclerosis. The development of ultrasound machines, advances in echocardiographic devices and high resolution transducers facilitate comprehensive analysis of epicardial fat thickness (EFT) and carotid –intima media thickness (C-IMT).Aim: To investigate the relationship of echocardiographic epicardial fat thickness (EFT) and carotid –intima media thickness (C-IMT) with the severity of coronary artery disease.Methods: A cross sectional multicenter diagnostic accuracy study carried out at Ibn Al-Nafis Cardiovascular Hospital, Ibn Al- Bitar Cardiology Center and Ghazi Al-Hariri Hospital –Iraqi Center for Cardiology during the period between October 2016 and May 2017 assessing. History regarding demographic data and risk factors was taken. Two dimensional transthoracic echocardiographic measurements were done. EFT was measured from parasternal long axis view perpendicular to the right ventricular free wall. C-IMT was measured according to that recommended by the American society of echocardiography (ASE).Results: The current study demonstrated that the EFT has a direct and significant correlation with the number of involved vessels (P value ˂ 0.001, r= 0.770). The validity of EFT to discriminate between multiple vessels disease and no vessel involvement is excellent (AUC= 0.984, cut point > 8mm, sensitivity=92.9%, specificity= 93.3%). There is inverse and significant correlation between ejection fraction (EF) and three vessels disease (P value ˂ 0.001, r= -0.507). Also there is a direct and significant correlation between C-IMT and severity of CAD. ROC analysis for validity of C-IMT to discriminate between multiple vessels disease and no vessel involvement is excellent (AUC= 0.961, cut point > 1.04mm, sensitivity=92.9%. specificity=86.7%). C-IMT is fair to discriminate between single vessel disease and no vessel involvement (AUC=0.738, cut point ˃ 0.84mm, sensitivity 100%), so if correlated with age, C-IMT above 0.84 can be used as a cut off point for the prediction of CAD. Finally, EFT and C-IMT are more likely to reflect severity of CAD than their ratio.Conclusions: C-IMT and EFT are simple and reproducible parameters that can be used as a screening tool for the presence and severity of CAD especially before symptoms appearance in high risk patients

Utility of cranial color Doppler sonography in preterm and term neonates

Introduction: Cranial Doppler sonography is emerging technique. The procedure is noninvasive, nonionizing, portable, and safe performed with relatively inexpensive equipment. Doppler transducer used to measure the velocity of blood flow within the circle of Willis. Cranial Doppler calculates and displays the peak systolic and diastolic velocity and the resistive index of blood flow within the vessel.Aims and Objectives: To assess utility of cranial color Doppler to evaluate cerebral blood flow velocities in ACA, MCA, and PCA in preterm and term neonates and to evaluate developmental interval changes. Material and Methods: This is a prospective study conducted in Khwaja Banda Nawaz teaching and general Hospital, Kalaburagi. A total of 52 neonates were evaluated during the study period from January 2019 to October 2019. The USG machine GE Logiq F8 series with high resolution transducer of 7-10 MHz was used during the present study. Transtemporal approach for color Doppler study. Inclusion criteria, all babies born within gestational age varied between 28 to 42 weeks and Exclusion criteria neonates with congenital heart disease and any other heart disease. Results: Intracranial velocities were seen to increase with increasing gestational age and with increasing age of the neonate; the resistive index decreased progressively with age. Correlation between the gestational age, and cranial Doppler evaluation was done p values were statistically significant at p

A New Application in Dermatological Ultrasound

As the high-resolution multifrequency transducers and multichannel color Doppler machines have been developed, dermatologic ultrasound imaging has been rapidly growing...

Contrast-enhanced ultrasonography of testicular tumours

Scrotal ultrasound with high-resolution transducers and additional display of vascularisation in colour-coded ultrasonography is the method of choice for the detection and characterisation of testicular tumors. Within the last decade, testicular ultrasonography has been further refined and improved by the possibilities of contrast-enhanced ultrasound (CEUS).CEUS may be especially helpful in the assessment of vascularisation disorders (e.g., incomplete torsion, segmental perfusion disorders, abscesses) or testicular foci remaining equivocal even after colour-coded ultrasonography.The basic idea in the application of CEUS in scrotal sonography is the possibility to differentiate between avascular, hypo- and hypervascular findings, with alack of perfusion generally considered as asign of benignity. Vice versa, detection of vascularisation speaks for neoplasia but not necessarily for malignity (e.g., Leydig cell tumors). CEUS is especially valuable in the correct classification of small (<1.5 cm) testicular foci.This review summarizes the present knowledge on indications, implications and limitations of the application of CEUS in testicular tumors.

Plea for a standardized imaging approach to disorders of sex development in neonates: consensus proposal from European Society of Paediatric Radiology task force.

This consensus article elaborated by the European Society for Paediatric Radiology task force on gastrointestinal and genitourinary imaging is intended to standardize the imaging approach in newborns with disorders of sex development. These newborns represent a difficult and stressful situation necessitating a multidisciplinary team approach. Imaging plays an important role in the work-up but needs to be optimized and customized to the patient. Ultrasound plays the central role in assessing the genital anatomy. The examination must be conducted in a detailed and systematic way. It must include transabdominal and transperineal approaches with adapted high-resolution transducers. The pelvic cavity, the genital folds, the inguinal areas and the adrenals must be evaluated as well as the rest of the abdominal cavity. A reporting template is proposed. The indications of magnetic resonance imaging and cysto- and genitography are discussed as well as they may provide additional information. Imaging findings must be reported cautiously using neutral wording as much as possible.

Skin cancer: findings and role of high-resolution ultrasound.

Currently available high-resolution transducers allow a detailed ultrasound (US) assessment of skin tumors. US complements clinical examination, dermoscopy, and biopsy in the initial differential diagnosis, surgical planning, locoregional staging, and follow-up of patients with skin malignancies. It is important for dermatologists, skin surgeons, and US operators to be aware of the US imaging findings and to recognize the clinical scenarios where imaging is indicated in the management of skin cancer. The purpose of this review article is to address the most common indications for US in skin oncology and to provide a comprehensive guide to the gray-scale and color-Doppler findings in cutaneous malignant tumors.

Investigating the relationship between ultrasound measured optic nerve sheath diameter and preeclampsia

Background: Increased intracranial pressure (ICP) is one of the main consequences of preeclampsia, which could be manifested by a change in the optic nerve sheath diameter as a radiologic and clinical sign. However, the effect of preeclampsia on the ultrasound measured optic nerve sheath diameter (ONSD) and its possible applications are rarely investigated. The aim of this study was to determine the relationship between ultrasound measured optic nerve sheath diameter and the risk of preeclampsia. Methods: This case-control study was performed on 38 pregnant women with normal blood pressure and 38 pregnant women with preeclampsia in Alzahra hospital in Rasht during 2018. A checklist was used to record demographic and clinical data. Measurements were made using a high resolution transducer, by placing the focal point and a cursor line at 3 mm behind the globe, perpendicular to the optic nerve axis (measuring the mean of two eyes). Data were analyzed by SPSS software version 21. Results: The mean age of patients with preeclampsia and normal pregnant women were 31.42 ± 6.2 years and 29.76 ± 3.46 years, respectively. Differences in gravidity (P = 0.854) and the history of hypertension (P = 0.946) in both groups were not statistically significant (P < 0.05). The mean optic nerve sheath diameter in women with preeclampsia was significantly higher than pregnant women with normal blood pressure (P = 0.001). The area under the ROC curve for the ONSD was 0.82 and the cut-off point for this index was calculated as 4.55 mm, which at this point, sensitivity and specificity were 78.9% and 73.7%, respectively. Conclusion: There was a relationship between the risk of preeclampsia and ONSD, in the way that the ONSD in preeclampsia patients was higher than that of normal subjects. However, the mean ONSD in two groups of mild and severe preeclampsia were not significantly different.

Analysis, Design, and Optimization of the CHOPFET Magnetic Field Transducer

This paper presents the study of the chopper-stabilized magnetic field effect transistor (CHOPFET), a high-resolution silicon magnetic transducer. After a full description of its structure and operating principle, a 3-D multiphysics model is proposed. This model combines the electrical model of conventional silicon electronic devices (i.e., transistors) and the magnetic model in order to obtain accurate transduction effect prediction. Experimental results collected from a set of CHOPFET transducers fabricated in AMS $0.35~\mu \text{m}$ standard CMOS technology effortlessly match the simulations performed on the same process. Analysis and discussions reveal one key result: when the CHOPFET is appropriately biased, its channel current, ${I}_{\text {DS}}$ , can be lowered without magnetic sensitivity loss, i.e., the CHOPFET can achieve high-resolution performance even when operated in a low-power mode.

The role of ultrasonography in the investigation of male infertility

Unintended childlessness affects approximately 9-15% of couples in the reproductive age. It is known that a remarkable proportion of infertility is caused by the disorders of the male reproductive functions. Diagnostic imaging methods and especially ultrasonography play a crucial role in the infertility work-up, the ultrasound examination has become the method of choice for imaging in diseases affecting the testis. With the development of high resolution transducers and technology using colour Doppler, pulsed Doppler, share wave elastography and strain elastography, it is now possible to make accurate diagnoses. However, the place of the new imaging methods in the algorithm of infertility check-up should be clearly defined. Orv Hetil. 2018; 159(21): 815-822.