High Frequency US Research Articles

US of the Penis: Beyond Erectile Dysfunction.

High-frequency US, with a linear transducer and gray-scale, color, and spectral Doppler US techniques, is the primary imaging modality for evaluation of the penis. It can allow delineation of anatomy and assessment of dynamic blood flow; it is easily available and noninvasive or minimally invasive; it is cost effective; and it is well tolerated by patients. US assessment after pharmacologic induction of erection is an additional tool in assessing patients with suspected vasculogenic impotence, and also in selected patients with penile trauma and suspected Peyronie disease. Penile injuries, life-threatening infections, and vascular conditions such as priapism warrant rapid diagnosis to prevent long-term morbidities due to clinical misdiagnosis or delayed treatment. US can facilitate a timely diagnosis in these emergency conditions, even at the point of care such as the emergency department, which can facilitate timely treatment. In addition, color and spectral Doppler US are valuable applications in the follow-up of patients treated with endovascular revascularization procedures for vasculogenic erectile dysfunction. Image optimization and attention to meticulous techniques including Doppler US is vital to improve diagnostic accuracy. Radiologists should be familiar with the detailed US anatomy, pathophysiologic characteristics, scanning techniques, potential pitfalls, and US manifestations of a wide spectrum of vascular and nonvascular penile conditions to suggest an accurate diagnosis and direct further management. The authors review a range of common and uncommon abnormalities of the penis, highlight their key US features, discuss differential diagnosis considerations, and briefly review management. ©RSNA, 2024 Supplemental material is available for this article.

High-Frequency US in Hepatobiliary Imaging.

High-Frequency US in Hepatobiliary Imaging.

Case 312: Dercum Disease

A 29-year-old woman was referred for US of bilateral breasts during evaluation for noncyclical mastalgia predominantly in the left breast of 8 months duration. She had been taking selective serotonin receptor inhibitors for the past 6 months for a clinical diagnosis of generalized anxiety disorder. A detailed medical history revealed breast cancer in the patient's mother and grandmother. There was no history of weight loss or appetite loss, nor was there a history of any altered bowel or bladder habits. The patient was overweight, with a body mass index of 26.8 kg/m2, and appeared anxious during the general physical examination, with an increased pulse (102 beats per minute) and normal blood pressure (118/82 mm Hg). Local examination revealed multiple small mobile painful lesions that were palpable in all quadrants of the bilateral breasts, anterior abdominal wall, and forearm. On further questioning, the patient reported similar painful lesions were present in her mother and one brother. Laboratory investigations showed a normal hemoglobin level (12.4 g/dL; normal range, 12-15 g/dL), a total leukocyte count of 9000 cells per microliter (9 cells × 109/L) (normal range, 4500-11 000 cells per microliter [4.5-11 cells × 109/L]), a normal differential leukocyte count (74% neutrophils [normal range, 40%-80%], 24% lymphocytes [normal range, 20%-40%], and 2% eosinophils [normal range, 1%-4%]), and an erythrocyte sedimentation rate of 5 mm per hour (normal range, 0-29 mm per hour). High-frequency US of bilateral breasts was performed in conjunction with Color Doppler US and shear-wave elastography of representative lesions in the breasts. Similar lesions were also found in the subcutaneous plane of the right forearm and the anterior abdominal wall.

Skin sonography in children: a review.

Skin lesions are not uncommon in children, and most of them are benign. However, they can be a matter of concern. Although in most cases the diagnosis can be suspected based on clinical history and physical examination, in some cases clinical findings are nonspecific. High-frequency color Doppler US is a noninvasive technique that can play a relevant role in these cases and give important anatomical information for final clinical management. US can be helpful to avoid unnecessary surgery, plan a surgical excision and avoid advanced imaging studies such as MRI and CT, which have a lower resolution for the skin. Different lesions can look similar on US, and clinical correlation is always important. The purpose of this article is to show a variety of skin lesions that occur in children, emphasizing clinical-sonographic correlation, and to familiarize pediatric radiologists with the US technique and sonographic appearance of common skin lesions in children.

High-Frequency US for BK Polyomavirus-associated Nephropathy after Kidney Transplant.

Background BK polyomavirus-associated nephropathy (BKPyVAN) is an important cause of chronic renal allograft dysfunction. However, US features indicative of BKPyVAN have not been fully evaluated. Purpose To assess the value of high-frequency US for the diagnosis of BKPyVAN in kidney transplant recipients. Materials and Methods In this prospective cohort study, participants who tested positive for BK viruria after kidney transplant from September 2019 to January 2021 were evaluated with high-frequency US 1 day before biopsy. Clinical characteristics and US features were compared between participants with and without BKPyVAN. Significant predictors associated with BKPyVAN were determined using logistic regression analyses. The area under the receiver operating characteristic curve (AUC) was used to evaluate diagnostic performance. Results A total of 105 participants who underwent kidney transplant (mean age, 38 years ± 11 [SD]; 63 men) were evaluated; 45 participants were diagnosed with BKPyVAN. Multivariable analysis demonstrated that eccentric hydronephrosis and subcapsular hypoechoic areas were independent factors for BKPyVAN. The AUC for predicting BKPyVAN according to subcapsular hypoechoic areas was 0.66 (95% CI: 0.55, 0.77), with a specificity of 92% (55 of 60 participants). The AUC of combined US (eccentric hydronephrosis plus subcapsular hypoechoic area) and clinical (urine BKPyV DNA load [BKPyV-DNA] plus BK viremia) features was 0.90, with a specificity of 92% (55 of 60 participants). Parenchymal hyperechoic and subcapsular hypoechoic areas were independent factors for differentiating BKPyVAN from transplant rejection. The pooled specificity of subcapsular hypoechoic areas was 96% (21 of 22 participants), with an AUC of 0.67 (95% CI: 0.54, 0.80). For the combination of US (parenchymal echogenicity plus subcapsular hypoechoic area) and clinical (urine BKPyV-DNA plus time since transplant) features, the AUC reached 0.92 and specificity was 82% (18 of 22 participants). Conclusion High-frequency US characteristics are valuable for diagnosing BK polyomavirus-associated nephropathy (BKPyVAN) and distinguishing BKPyVAN from rejection in kidney transplant recipients. © RSNA, 2022 Online supplemental material is available for this article.

Radiologic Approach for Skin US.

Radiologic Approach for Skin US.

Corrigendum

Financial Markets, Institutions & InstrumentsVolume 30, Issue 3 p. 84-84 CORRIGENDUMFree Access Corrigendum This article corrects the following: High Frequency Trading and US Stock Market Microstructure: A Study of Interactions between Complexities, Risks and Strategies Residing in U.S. Equity Market Microstructure Samir Abrol, Benjamin Chesir, Nikhil Mehta, Ron Ziegler, Volume 25Issue 2Financial Markets, Institutions & Instruments pages: 107-165 First Published online: April 21, 2016 First published: 12 June 2021 https://doi.org/10.1111/fmii.12149AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat The author Ron Ziegler was added to Samir Abrol et al. The author byline would thus read: Samir Abrol, Benjamin Chesir, Nikhil Mehta, and Ron Ziegler The online version of this article was corrected. The authors regret these errors. REFERENCE Abrol S, Chesir B, Mehta N, & Ziegler R. High Frequency Trading and US Stock Market Microstructure: A Study of Interactions between Complexities, Risks and Strategies Residing in U.S. Equity Market Microstructure. Financial Markets, Institutions & Instruments. 2016, 25, 107– 165. https://doi.org/10.1111/fmii.12068Wiley Online LibraryGoogle Scholar Volume30, Issue3August 2021Pages 84-84 ReferencesRelatedInformation

Heat-Related Illnesses Transported by United States Emergency Medical Services.

Background and objectives: Heat-related illness (HRI) can have significant morbidity and mortality consequences. Research has predominately focused on HRI in the emergency department, yet health care leading up to hospital arrival can impact patient outcomes. Therefore, the purpose of this study was to describe HRI in the prehospital setting. Materials and Methods: A descriptive epidemiological design was utilized using data from the National Emergency Medical Services (EMS) Information System for the 2017–2018 calendar years. Variables of interest in this study were: patient demographics (age, gender, race), US census division, urbanicity, dispatch timestamp, incident disposition, primary provider impression, and regional temperatures. Results: There were 34,814 HRIs reported. The majority of patients were white (n = 10,878, 55.6%), males (n = 21,818, 62.7%), and in the 25 to 64 age group (n = 18,489, 53.1%). Most HRIs occurred in the South Atlantic US census division (n = 11,732, 33.7%), during the summer (n = 23,873, 68.6%), and in urban areas (n = 27,541, 83.5%). The hottest regions were East South Central, West South Central, and South Atlantic, with peak summer temperatures in excess of 30.0 °C. In the spring and summer, most regions had near normal temperatures within 0.5 °C of the long-term mean. EMS dispatch was called for an HRI predominately between the hours of 11:00 a.m.–6:59 p.m. (n = 26,344, 75.7%), with the majority (27,601, 79.3%) of HRIs considered heat exhaustion and requiring the patient to be treated and transported (n = 24,531, 70.5%). Conclusions: All age groups experienced HRI but particularly those 25 to 64 years old. Targeted education to increase public awareness of HRI in this age group may be needed. Region temperature most likely explains why certain divisions of the US have higher HRI frequency. Afternoons in the summer are when EMS agencies should be prepared for HRI activations. EMS units in high HRI frequency US divisions may need to carry additional treatment interventions for all HRI types.

Nerve Fascicle Depiction at MR Microscopy and High-Frequency US with Anatomic Verification.

In correlation to histologic cross-sections, nerve microanatomy depiction is possible with high-frequency US; however, MR microscopy is superior to high-frequency US as even finer anatomic details ...

Role of High Frequency Ultrasound in Diagnosing Carpal Tunnel Syndrome as Compared with Conventional Nerve Conduction Studies.

Objective:Our aim was to evaluate High Frequency Ultrasonography as a tool for diagnosis in patients withcarpal tunnel syndrome in comparison with electrophysiological study.Methods:Thirty- one patients [56 hands] with CTS and twenty-five asymptomatic controls [50 hands] were assessed and underwent ultrasonography of the wrists and electrophysiological testing. Data from the patient and the control groups was compared for both the investigations to determine the CTS and the grade of severity.Results:There was a high degree of correlation between the conduction abnormalities of the median nerve as detected by electrodiagnostic tests, historic and objective scale [Hi-Ob] and the measurement of the cross-sectional area of the nerve by US (P < 0.05). A cut-off point of 0.88 mm2 for the mean cross-sectional area of the median nerve was found to be the upper limit for normal values. Compared to Ultrasonography which found one hand negative, six hands (10%) were negative on the electrophysiological tests. Using critical CSA value of 1.0 mm2 in these CTS cases by US with sensitivity and specificity of 100% and 88%. Based on the results of this study, ultrasonography of wrist is another useful tool along with nerve conduction studies as per sensitivity and specificity patterns found in our study in diagnosis of carpal tunnel syndrome.Conclusion:High-frequency US examination of the median nerve and measurement of its cross-sectional area can be strongly considered as useful diagnostic diagnostic modality for the evaluation of CTS along with nerve conduction studies. In addition to its high diagnostic accuracy it is able to define the cause of nerve compression, aids treatment planning and provides a reliable method to follow response to therapy.

The Impacts of High-Frequency US Uncertainty Shocks on China’s Investment and Bank Loans: Evidence From Mixed-Frequency VAR

The Impacts of High-Frequency US Uncertainty Shocks on China’s Investment and Bank Loans: Evidence From Mixed-Frequency VAR

Accuracy of point-of-care ultrasound using low frequency curvilinear transducer in the diagnosis of shoulder dislocation and confirmation of appropriate reduction

BackgroundUltrasound (US) is an effective modality in the evaluation of shoulder dislocation and reduction. In most studies, high frequency US probes have been used. ObjectiveTo determine the sensitivity and specificity of low frequency US in the diagnosis of shoulder dislocation and its proper reduction in the emergency department (ED). MethodsIn a prospective observational study 84 patients, suspicious of shoulder dislocation, were enrolled in our study. In ED, they all underwent low frequency (curve) probe US examination by the emergency physician at the time of admission. Standard radiographies of their shoulder joints were taken later and then reported by the attending radiologist. As soon as the shoulder dislocation was confirmed, reduction of the joint was done under procedural sedation and analgesia. US and radiography of the relocated joint were taken for the second time. The sensitivity and specificity of low frequency US were compared with radiography by the appropriate statistical analysis. ResultsIn comparison to radiography, US had a sensitivity of 100.0%, specificity of 80.0%, positive predictive value of 98.7%, and negative predictive value of 100.0% in diagnosis of shoulder dislocation. The specificity of US in diagnosis of proper reduction of the joint, was estimated to be 98.7% with a negative predictive value of 100.0%. US took a significantly less time than radiography to be performed (p < 0.001). ConclusionsLow frequency US is highly accurate in diagnosing shoulder dislocation and its proper reduction. Thus it might be a good substitute for radiography in these situations.

Analysis of process intensification in enzyme catalyzed reactions using ultrasound

Intensification of enzyme catalyzed reactions using US is analyzed by use of enzyme catalyzed esterification as model reaction. Lipozyme CALB L is taken as model enzyme in free and immobilized form. This allowed the clarification of the underlying mechanisms of the phenomena. Process intensification was tested both with low frequency (high amplitude) and high frequency (low amplitude) US. Reaction behavior with US was compared with stirring. For the immobilized enzyme the reaction rate increased by a factor of 2.2 by applying low frequency US, however, the cavitation from US damaged the enzyme carrier particles. For the free enzyme low frequency US produced a 22 times faster reaction rate compared with stirring, and the enzyme molecules were not damaged and could be reused. With high frequency US no improvement of reaction rate was observed. The ultrasonic conditions necessary for achieving intensification were identified.

High Frequency Trading and US Stock Market Microstructure: A Study of Interactions betweenComplexities, Risks and Strategies Residing in U.S. Equity Market Microstructure

We examine the conditions, complexities and risks of a fragmented market microstructure to contextualize the role of algorithmic and high frequency trading in the US equity markets. The establishment of a national market system and Regulation NMS was meant to promote competition, recognizing the evolution and changing dynamics introduced by technological innovation. This evolution and governing rule set has had many positive effects in terms of competition, fee compression, tighter spread potential and volumes. Our paper identifies certain unintended consequences and complexities of the national market system including fragmentation, sub second quoting and trading, complex order types, data asymmetry, technological innovation, unique strategies and the algorithms that power them. When acting in concert, these complexities give rise to opportunities as well as emerging risks.This high‐speed system can be unstable and susceptible to inherent conflicts of interest, market abuse and price shocks. These shocks can be amplified by positive feedback loops accelerating single stock declines and also posing systemic risks in time scales beyond real‐time physical human comprehension and reaction times. Furthermore they can produce contagion, which we refer to as ‘Flash Splashes’ caused by rapid withdrawals and injections of liquidity in increasingly linked asset classes, indices, sectors and global liquidity pools. High frequency trading strategies can be both passive and aggressive and usually display risk averse and low inventory characteristics. These strategies leverage fragmentation as they create or capture informational asymmetries. They interact directly with sell side algorithms that can hide intentions, hunt liquidity and sweep the order book. These interactions create market dynamics that can benefit and challenge anyone exposed to US equity markets.Every market participant has a risk profile unique to their strategy and objective and while regulations will be enriched or revised and certain unfair practices eliminated great attention should be paid to understanding modern high speed trading risks and both the positive and negative impacts on all stakeholders. We have examined the regulations, complexities and risks to bring clarity and understanding to the current trading ecosystem for its users.

Radiolabelled white blood cell scintigraphy in the work-up of dermal filler complications

Scintigraphy with radiolabelled autologous white blood cells (WBC) is a widely used method for the detection of sites of infection. In this study we evaluated the role of WBC scintigraphy in the diagnosis and follow-up of patients with suspected soft tissue infection caused by dermal fillers in the face. We compared several qualitative and quantitative interpretation criteria and the results obtained with MRI and high-frequency US (HFUS). Between 2007 and 2011, ten consecutive patients (all women) aged between 25 and 65years showing a reaction to dermal fillers were enrolled in the study. In five of these patients WBC scintigraphy was repeated at the end of therapy. Scintigraphy with (99m)Tc-HMPAO-labelled WBC was performed in each patient acquiring planar and SPECT images at 3h and 20h as well as HFUS with Doppler analysis and MRI with Gd-DTPA. The final diagnosis was determined by fine-needle aspiration and microbiological analysis of lesions in eight patients (before therapy in six and after therapy in two) and by clinical data and follow-up (at least 1year) in seven patients (before therapy in four and after therapy in three). Two patients were treated with steroids, and the others were treated with antibiotics for 3weeks. Several qualitative and semiquantitative interpretation criteria were applied to define the best strategy for accurate diagnosis of infections, implemented by SPECT images in patients with doubtful planar scans. The WBC scintigraphy results were also compared with the MRI and HFUS results. Sensitivity, specificity and accuracy were respectively 90%, 100% and 93.3% for WBC scintigraphy with qualitative and semiquantitative interpretation of planar images and 100%, 100% and 100% with qualitative analysis of SPECT images. Sensitivity, specificity and accuracy for HFUS were 44%, 66% and 50%, and for MRI were 50%, 100% and 67.6%, respectively. Scans performed after therapy in five patients were negative in three and still positive in two (all true results). In conclusion, scintigraphy with radiolabelled WBC was found to be the most accurate method for diagnosing infection in patients with long-term dermal filler complications, particularly using qualitative analysis of SPECT images. No differences were observed with planar images using either qualitative or semiquantitative analysis. HFUS and MRI may provide additional important information for defining the nature of the filler and for surgery, but are not accurate enough for diagnosing infection.

Cojumping: Evidence from the US Treasury bond and futures markets

The basis between spot and future prices will be affected by jump behavior in each asset price, challenging intraday hedging strategies. Using formal cojumping tests this paper considers the cojumping behavior of spot and futures prices in high frequency US Treasury data. Cojumping occurs most frequently at shorter maturities and higher sampling frequencies. We find that the probability of cojumping is altered by the presence of an anticipated macroeconomic news announcement. The probability of cojumping is particularly affected by news surprises in non-farm payrolls, CPI, GDP and retail sales. However, the two cojumping tests are also more likely to provide contradictory results in the presence of surprises in non-farm payrolls. On these occasions the market does not clearly signal its short term pricing behavior.

Ultraschall am Bewegungsapparat I - «Perlen und Kristalle»

This article reviews the applications of high resolution ultrasound (HRUS) which were discussed at the SGUM congress in Davos in the talk «pearls and crystals». Sonography is an excellent and validated tool in the diagnostics and assessment e.g. of spondylo-arthritis and crystal deposition diseases. Enthesitis is a typical feature of SpA. The Sensitivity of HRUS diagnosing enthesitis is higher compared to the clinical examination. High frequency US probes allow furthermore an accurate assessment in crystal deposition diseases. Sonography is able to detect various typical pathologies in gout, pseudogout and apatite deposition disease. Will HRUS in the near future be able to replace microscopy in the diagnostics of crystal deposition diseases?

The Effects of US Macroeconomic Surprises on the Intraday Movements of Foreign Exchange Rates: Cases of USD-EUR and USD-JPY Exchange Rates

This paper characterizes the intraday dynamics of the high frequency US Dollar (USD)–Euro (EUR) and US Dollar (USD)–Japanese Yen (JPY) foreign exchange rates that have been subject to macroeconomic fundamentals. Even though the FIGARCH model with a normality assumption is found to be a good starting point, it appears to be inappropriate to represent the underlying movements of the high frequency returns due to the occurrences of jumps. Hence, this paper relies on the FIGARCH model with the mixture distribution that allows for the time-varying jumps that are determined by the US macroeconomic surprises. This paper generally finds that the US macroeconomic surprises are closely related to the intraday movements in the volatility process of the high frequency returns process through the jumps. In particular, the US macroeconomic surprises appear to affect the movements in the volatility process of the foreign exchange rates asymmetrically depending on the signs of the surprises and spuriously increasing the long memory persistence in the volatility process due to the jumps.

New potential and applications of contrast-enhanced ultrasound of the breast; own investigations and review of the literature

Imaging of angiogenesis is a challenge for modern imaging. Velocimetry in malignant breast lesions and density of malignant vessels are very low. In breast imaging, first results of contrast-enhanced ultrasound (CEUS) were disappointing. Microbubbles are fragile when examined with high frequency US, commonly used in breast imaging. Second-generation contrast agents increase intensively the signal level of breast lesions and new sequences like CPS (Coherence Pulse Sequencing) might be accurate to detect malignant vessels in breast lesions for characterization, to assess the extent of infiltrative breast carcinoma or to evaluate the tumor response after chemotherapy. Another interesting clinical application is the differentiation between post-operative changes and recurrences. In this review, we detail the main results obtained with contrast ultrasonography in a characterization study. In malignant lesions, enhancement was fast, starting with less than 20 s. Compared to MR, enhancement appeared faster. Malignant vessels were predominant in the external ring of the nodule, conversely vessels were seen in the center of the lesion in benign nodules. Malignant vessels were also seen outside the lesion. This knowledge could lead the surgeon to perform a larger lumpectomy in these cases, to obtain sane margins and to reduce recurrences. © 2008 Elsevier Ireland Ltd. All rights reserved.

Segmental testicular infarction in a young man simulating a testicular tumor

A 19-year-old boy presented with a 48-hour history of acute onset severe right scrotal pain with minimal scrotal swelling. High-frequency US including color Doppler demonstrated a wedge-shaped, heterogeneous, avascular testicular mass diagnosed preoperatively as a segmental testicular infarction (STI). This was proved at surgery and subsequent histology. The preoperative diagnosis of STI was suggested based on the young man's presentation of severe pain and the sonographic appearance of the mass. Entertaining the preoperative diagnosis of STI from a testicular tumor is important for testis-sparing surgery even though STI in the pediatric age group is extremely rare.