Acoustic Shadowing Research Articles

Imaging and Pathologic Evaluation of Cryoablation of Woodchuck (Marmota Monax) Hepatocellular Carcinoma.

We characterized cryoablation as a mode of clinical intervention in adult woodchucks with hepatocellular carcinoma (HCC). Woodchucks (n = 4) were infected with woodchuck hepatitis virus at birth and developed LI-RADS-5 hypervascular HCC. At 21 mo of age, they underwent ultrasound (US), contrast-enhanced CT (CECT) imaging, and US-guided subtotal cryoablation (IcePearl 2.1 CX, Galil, BTG) of their largest tumor (Mean HCC volume of 49 ± 9 cm³). Cryoablation was performed using two 10-min freeze cycles, each followed by an 8-min thaw cycle. The first woodchuck developed significant hemorrhage after the procedure and was euthanized. In the other 3 woodchucks, the probe track was cauterized and all 3 completed the study. Fourteen days after ablation, CECT was performed, and woodchucks were euthanized. Explanted tumors were sectioned using subject-specific, 3D-printed cutting molds. Initial tumor volume, the size of the cryoablation ice ball, gross pathology and hematoxylin and eosin-stained tissue sections were evaluated. On US, the edges of the solid ice balls were echogenic with dense acoustic shadowing and average dimensions of 3.1 ± 0.5 × 2.1 ± 0.4 cm and cross-sectional area of 4.7 ± 1.0 cm ². On day 14 after cryoablation, CECT of the 3 woodchucks showed devascularized hypo-attenuating cryolesions with dimensions of 2.8 ± 0.3 × 2.6 ± 0.4 × 2.93 ± 0.7 cm and a cross-sectional area of 5.8 ± 1.2 cm². Histopathologic evaluation showed hemorrhagic necrosis with a central amorphous region of coagulative necrosis surrounded by a rim of karyorrhectic debris. A rim of approximately 2.5 mm of coagulative necrosis and fibrous connective tissue clearly demarcated the cryolesion from adjacent HCC. Partial cryoablation of tumors produced coagulative necrosis with well-defined ablation margins at 14 d. Cauterization appeared to prevent hemorrhage after cryoablation of hypervascular tumors. Our findings indicate that woodchucks with HCC may provide a predictive preclinical model for investigating ablative modalities and developing new combination therapies.

Hybrid Message-Passing Interface-Open Multiprocessing Accelerated Euler-Lagrange Simulations of Microbubble Enhanced HIFU for Tumor Ablation.

Microbubble enhanced high intensity focused ultrasound (HIFU) is of great interest to tissue ablation for solid tumor treatments such as in liver and brain cancers, in which contrast agents/microbubbles are injected into the targeted region to promote heating and reduce prefocal tissue damage. A compressible Euler-Lagrange coupled model has been developed to accurately characterize the acoustic and thermal fields during this process. This employs a compressible Navier-Stokes solver for the ultrasound acoustic field and a discrete singularities model for bubble dynamics. To address the demanding computational cost relevant to practical medical applications, a multilevel hybrid message-passing interface (MPI)-open multiprocessing (OpenMP) parallelization scheme is developed to take advantage of both scalability of MPI and load balancing of OpenMP. At the first level, the Eulerian computational domain is divided into multiple subdomains and the bubbles are subdivided into groups based on which subdomain they fall into. At the next level, in each subdomain containing bubbles, multiple OpenMP threads are activated to speed up the computations of the bubble dynamics. For improved throughput, the OpenMP threads are more heavily distributed to subdomains where the bubbles are clustered. By doing this, MPI load imbalance issue due to uneven bubble distribution is mitigated by OpenMP speedup locally for those subdomains hosting more bubbles than others. The hybrid MPI-OpenMP Euler-Lagrange solver is used to conduct simulations and physical studies of bubble-enhanced HIFU problems containing a large number of microbubbles. The phenomenon of acoustic shadowing caused by the bubble cloud is then analyzed and discussed. Efficiency tests on two different machines with 48 processors are conducted and indicate 2-3 times speedup with the same hardware by introducing an OpenMP parallelization in combination with the MPI parallelization.

Ultrasonographic Patterns of Calcium Hydroxyapatite According to Dilution and Mix With Hyaluronic Acid.

To assess the ultrasonographic patterns of different calcium hydroxyapatite (CaHA) formulations, including the undiluted, diluted, and mixed with hyaluronic acid (HA) compounds. To review the ultrasonographic images of patients ≥18 years with confirmed injections of CaHA clinically and ultrasonographically, and without different concomitant types of fillers in the same region or other systemic or localized cutaneous diseases. Twenty-one patients met the criteria (90% female; 10% male; mean age: 52 years ± 12.8). Of these, 33.3% have been injected with an undiluted formulation, 33.3% with diluted, and 33.3% with a mixed formulation. All cases were studied with devices presenting frequencies that ranged from 18 to 24 MHz. Twelve cases (57%) were also studied with the 70 MHz. The ultrasonographic patterns of CaHA presented differences in the presence and intensity of PAS and the degree of inflammation according to the dilution and mix with HA. Diluted formulations show a milder intensity posterior acoustic shadowing (PAS) artifact than undiluted at 18-24 MHz. In mixed formulations, 57% showed mild PAS, and 43% demonstrated no PAS artifact at 18-24 MHz, besides fewer inflammatory changes in the periphery of the deposits. The ultrasonographic patterns of CaHA show differences in the presence and intensity of PAS and the degree of inflammation according to the dilution and mix with HA. Awareness of these ultrasonographic variations can support better discrimination of CaHA.

Sonographic and Magnetic Resonance Characteristics of Gynecological Sarcoma.

Gynecological sarcomas are rare malignant tumors with an incidence of 1.5-3/100,000 and are 3-9% of all malignant uterine tumors. The preoperative differentiation between sarcoma and myoma becomes increasingly important with the development of minimally invasive treatments for myomas, as this means undertreatment for sarcoma. There are currently no reliable laboratory tests or imaging-characteristics to detect sarcomas. The objective of this article is to gain an overview of sarcoma US/MRI characteristics and assess their accuracy for preoperative diagnosis. A systematic literature review was performed and 12 studies on ultrasound and 21 studies on MRI were included. For the ultrasound, these key features were gathered: solid tumor > 8 cm, unsharp borders, heterogeneous echogenicity, no acoustic shadowing, rich vascularization, and cystic changes within. For the MRI, these key features were gathered: irregular borders; heterogeneous; high signal on T2WI intensity; and hemorrhagic and necrotic changes, with central non-enhancement, hyperintensity on DWI, and low values for ADC. These features are supported by the current literature. In retrospective analyses, the ultrasound did not show a sufficient accuracy for diagnosing sarcoma preoperatively and could also not differentiate between the different subtypes. The MRI showed mixed results: various studies achieved high sensitivities in their analysis, when combining multiple characteristics. Overall, these findings need further verification in prospective studies with larger study populations.

Nomogram based on the O-RADS for predicting the malignancy risk of adnexal masses with complex ultrasound morphology

ObjectiveThe accurate preoperative differentiation of benign and malignant adnexal masses, especially those with complex ultrasound morphology, remains a great challenge for junior sonographers. The purpose of this study was to develop and validate a nomogram based on the Ovarian-Adnexal Reporting and Data System (O-RADS) for predicting the malignancy risk of adnexal masses with complex ultrasound morphology.MethodsA total of 243 patients with data on adnexal masses with complex ultrasound morphology from January 2019 to December 2020 were selected to establish the training cohort, while 106 patients with data from January 2021 to December 2021 served as the validation cohort. Univariate and multivariate analyses were used to determine independent risk factors for malignant tumors in the training cohort. Subsequently, a predictive nomogram model was developed and validated in the validation cohort. The calibration, discrimination, and clinical net benefit of the nomogram model were assessed separately by calibration curves, receiver operating characteristic (ROC) curves, and decision curve analysis (DCA). Finally, we compared this model to the O-RADS.ResultsThe O-RADS category, an elevated CA125 level, acoustic shadowing and a papillary projection with color Doppler flow were the independent predictors and were incorporated into the nomogram model. The area under the ROC curve (AUC) of the nomogram model was 0.958 (95% CI, 0.932–0.984) in the training cohort. The specificity and sensitivity were 0.939 and 0.893, respectively. This nomogram also showed good discrimination in the validation cohort (AUC = 0.940, 95% CI, 0.899–0.981), with a sensitivity of 0.915 and specificity of 0.797. In addition, the nomogram model showed good calibration efficiency in both the training and validation cohorts. DCA indicated that the nomogram was clinically useful. Furthermore, the nomogram model had higher AUC and net benefit than the O-RADS.ConclusionThe nomogram based on the O-RADS showed a good predictive ability for the malignancy risk of adnexal masses with complex ultrasound morphology and could provide help for junior sonographers.

Evaluating Spatiotemporal Trends in Infrasound Propagation Using Seismoacoustic Arrivals from Repeating Explosions

ABSTRACT Recent studies have demonstrated the utility of seismic stations for recording acoustic signals from events of interest. Here, we present an analysis of seismoacoustic arrivals originating from weekly controlled munition disposals at the McAlester Army Ammunition Plant (McAAP) in Oklahoma over a period of nine months during 2019. These arrivals were recorded on 121 temporary and permanent seismic stations across Oklahoma and surrounding states. Arrivals were identified by a human analyst team. Because of its consistency and duration, the McAAP dataset provides an opportunity to study the spatial and temporal variability of infrasound propagation because it relates to seasonally variable atmospheric conditions. Recorded arrivals identify an acoustic shadow zone ranging in distance from 50 to 200 km of the source, along with seasonal directional shifts in the stratospheric duct. Acoustic raytracing is used to produce comparisons of predicted and observed arrival dynamics, concluding that current atmospheric specifications do not capture the full complexity of the atmosphere.

Correlation of androgen receptor with ultrasound, clinicopathological features and clinical outcomes in breast cancer

BackgroundThis study aimed to explore whether there is an association between androgen receptor (AR) expression and ultrasound, clinicopathological features and prognosis of breast cancer.MethodsA total of 141 breast cancer patients were included in this retrospective study. AR expression was analyzed by immunohistochemistry. The images of B-mode, color Doppler and strain elastography from 104 patients were collected continuously, and the corresponding ultrasound characteristics were obtained. The differences in ultrasound and clinicopathological features in different AR status were analyzed. Progression-free survival (PFS) of patients was obtained through up to 90 months of follow-up; then, the effect of AR on PFS was analyzed. Subsequently, a nomogram was constructed to predict the AR status. The predictive accuracy was calculated using C-index.ResultsThe positive expression of AR (AR +) was associated with lower histological grade (p = 0.034) and lower Ki-67 level (p = 0.029). Triple-negative breast cancer (TNBC) had the lowest probability of AR + (p < 0.001). The AR + group mostly showed unsmooth margin (p < 0.001), posterior acoustic shadowing (p = 0.002) and higher elasticity score (p = 0.022) on ultrasound. The echo pattern of most tumors with AR + was heterogeneous (p = 0.024) in Luminal A subtype. AR + could be a sign of a better prognosis in overall breast cancer (p < 0.001), as well as in human epidermal growth factor receptor 2 (HER2) overexpression and Luminal B subtypes (p = 0.001 and 0.025). The nomogram showed relatively reliable performance with a C-index of 0.799.ConclusionOur research demonstrated that AR expression was closely related to ultrasound, clinicopathological features and prognosis of breast cancer.

MODERN POSSIBILITIES OF ULTRASOUND SCAN IN DIAGNOSIS OF MORTON'S NEUROMA

About 60% of healthy people at least once in their lives complained of pain in the anterior foot that was diagnosed as Morton's neuroma. According to numerous resources, ultrasound scan is one of the leading methods for diagnosing the condition of the soft tissues in the foot, thus, this diagnostic technique can be considerably helpful in determining the nature and extent of the pathological condition and making the decision about the necessity of surgical treatment. Aim: to assess the potential of ultrasound investigation and to systematize the ultrasound criteria for Morton's neuroma using a two-dimensional mode, colour and energy mapping, and functional ultrasonography. Material and methods. We analyzed the findings obtained by the ultrasound scan of soft tissues in the foot of 26 people who complained of pain in the projection of 3-4 metatarsophalangeal joints. The following echographic data were evaluated: homogeneity, echogenicity, integrity of the soft tissues of the intermetatarsal spaces and tendons of the fingers, the presence of effusion in the articular capsules and tendon sheaths, the number of vascular signals in the affected area during power Doppler mapping. Results and discussion. In the control group of patients, the analysis of ultrasound has revealed the following echographic features: the contour of the cortical layer of the metatarsal bones is represented by a hyperechoic line with a clear acoustic shadow along it in all cases (100%); flexor tendons of the toes are located above the surfaces of the bones (100%); no masses are found in the intermetatarsal spaces in 100% of cases; the width of the intermetatarsal spaces is 5.0–9.0 mm in all cases (100%). In the main group of patients, the analysis of ultrasound findings has revealed the following structural changes: the contour of the cortical layer of the metatarsal bones is represented by a hyperechoic circular line with a clear acoustic shadow along it in 8 cases (30.7%); in 18 cases (69.3%) the contour of the cortical layer is uneven with a fuzzy acoustic shadow; flexor tendons of the toes are of reduced echogenicity and have heterogeneous structure in 16 cases (61.5%); space-occupying formations have been found in the intermetatarsal spaces of the III-IV toes in 24 cases (92.3%), and in the intermetatarsal spaces of the II-III toes and in 2 cases (7.7%); the width of the intermetatarsal spaces at the location of the mass formation in all cases (100%) is 10.0-15.0 mm. Conclusion. At the present, the access to ultrasound, its non-invasiveness, the absence of ionizing radiation, the possibility of dynamic observation, and relatively high accuracy in assessing the tibial nerve put it at the forefront in the diagnostic algorithm for detecting Morton's neuroma.

Application of endoscopic ultrasound to the descending colon and rectum in normal dogs.

Endoscopic ultrasound (EUS) is a medical procedure in which endoscopy is combined with ultrasonography (US) to compensate for problems associated with the transabdominal US such as large penetration depths, presence of intestinal gas, and acoustic shadowing. This prospective, method comparison, pilot study was performed to assess the feasibility of applying EUS in the colorectal region and to describe the typical EUS features of the descending colon and rectum in healthy dogs. Transabdominal US and EUS with or without the hydrosonography were applied to the descending colon and rectum in 10 clinically healthy Beagle dogs and wall thickness, visibility of the wall layers, and conspicuity of the mucosal and serosal surfaces of the intestinal wall were assessed. Endoscopic ultrasound enabled circumferential evaluation of the colorectal wall and provided better visibility of the wall layers and conspicuity of the mucosal and serosal surfaces without degradation of the image, even in the far-field portion of the colorectal wall, compared to US. Moreover, EUS provided the adequate image quality of the rectum, which was difficult to evaluate with US due to deep scan depth and acoustic shadowing by the pelvis. Meanwhile, the application of hydrosonography to EUS deteriorated the visibility of the wall layers and conspicuity of the intestinal wall. The results of this study demonstrate the feasibility of EUS to assess the colorectal region and its potential application for the evaluation of rectal masses or intrapelvic lesions that are inaccessible by the transabdominal US in dogs.

Ultrasonographic assessment of early leakage in intestinal sutures in dogs.

Intestinal suture dehiscence is one of the most feared complications following gastrointestinal surgery in both human and veterinary medicine, increasing the morbidity and mortality of these patients. Clinical and laboratory early signs of septic peritonitis are not always easily identifiable while prompt treatment should help decrease postoperative morbidity and mortality. The aim of this study is to describe the ultrasonographic (US) features of confirmed leakage of intestinal sutures (LIS) and to evaluate if this imaging technique can be useful as noninvasive tool for the early diagnosis of LIS. Seven dogs developed LIS in a range of three-four days after gastrointestinal surgery and four of these developed a second dehiscence. On B-mode ultrasonography, all intestinal surgical sites were identified and characterized by a bowel focal thickening with reduced or absent wall layering and the presence of hyperechoic, double-walled foci at regular intervals (suture material). Furthermore, hyperechoic linear interfaces associated with dirty acoustic shadowing and comet-tail artifacts crossing the intestinal wall to free-float in peritoneal cavity or in a saccate collection have been documented. On the basis of these preliminary results, canine abdominal ultrasound seems to be a useful diagnostic technique for post-operative monitoring of patients undergoing intestinal surgery, allowing early detection of signs of a LIS, before the patient develops clinical signs of septic peritonitis.

Caseous Mitral Annular Calcification Presenting as Retinal Artery Occlusion

Caseous mitral annular calcification (CMAC), sometimes called liquefaction necrosis of mitral annular calcification (MAC), is a rare variant of MAC, a chronic degenerative process that progresses with age. It is a degenerative abnormality of the fibrous tissue and typically involves the posterior annulus, appearing as a smooth mass with no flow or acoustic shadow artefacts. It can be differentiated from other cardiac masses by CT and MRI. Whilst benign in nature, it is associated with a range of pathologies, such as mitral valve dysfunction, arrhythmias, and systemic embolisation. Given the risk of systemic embolisation, surgery may be appropriate, but there is no clear consensus in the literature in patients who are asymptomatic. This case highlights a case of CMAC presenting with a retinal artery occlusion, and was managed conservatively. Background The mitral annulus is a key component of the mitral valve, ensuring appropriate function by facilitating complete closure of the leaflets during systole. With age, MAC can occur, potentially resulting in mitral valve dysfunction, infective endocarditis, and arrhythmias. CMAC is a rare variant of MAC, typically involving the posterior annulus. Whilst benign, the risk of complications, such as systemic embolisation, may indicate a surgical approach to management, even in patients who are asymptomatic. Case Presentation A 60-year-old female, presenting with sudden loss of vision in the lower part of her left eye due to a branch retinal artery embolus, was admitted from ophthalmology services. An outpatient transthoracic echocardiogram showed an abnormal mass on the posterior annulus of the mitral valve. Transoesophageal echocardiography identified a calcified posterior aspect of the mitral annulus with normal leaflet mobility and trivial regurgitation, and an echogenic mass attached to the ventricular aspect of the mitral annulus (at the level of posteromedial commissure), 9x4 mm in size. A cardiac CT showed a caseous mitral valve with evidence of rupture of the calcified shell. Discussion with the surgical multidisciplinary team resulted in a conservative approach, with follow-up echo for monitoring. Conclusion Whilst a benign and rare variant of MAC, CMAC is associated with a range of pathologies, including mitral valve disease, arrhythmias, and systemic embolisation. Currently, there is no standardised management approach for CMAC. Surgery is currently recommended in the context of already known surgically indicated pathologies, such as severe mitral valve disease or systemic embolisation. However, this conservatively-managed patient has had no further complications with stable echocardiographic appearance on repeat echo 3 months following initial exam.

Turbulent scattering in upwardly refracting atmospheres : towards a practical approach

Neglecting turbulent scattering when modelling sound propagation in an upwardly refracting atmosphere leads to unrealistically low levels. Engineering models then typically impose a distance independent constant value for the sound pressure level relative to free field propagation. However, such an approach neglects the strong temporal variability in level one might observe in such an acoustic shadow zone, depending on whether the atmospheric boundary layer is either strongly or weakly scattering. In this work, a modelling framework is presented to account for the effect of such changing scattering contributions, showing that level variations might be as large as 20 dB in such zones. This work contributes to predicting more accurate long-term sound pressure level distributions e.g. near wind turbines.

Artifacts and Technical Considerations at Contrast-enhanced US

Contrast-enhanced US (CEUS), similar to other radiologic modalities, requires specific technical considerations and is subject to image artifacts. These artifacts may affect examination quality, negatively impact diagnostic accuracy, and decrease user comfort when using this emerging technique. Some artifacts are related to commonly known gray-scale US artifacts that can also appear on the contrast-only image (tissue-subtracted image obtained with the linear responses from background tissues nulled). These may include acoustic shadowing and enhancement; reverberation, refraction, and reflection; and poor penetration. Other artifacts are exclusive to CEUS owing to the techniques used for contrast mode image generation and the unique properties of the microbubbles that constitute ultrasound-specific contrast agents (UCAs). UCA-related artifacts may appear on the contrast-only image, the gray-scale image, or various Doppler mode images. Artifacts related to CEUS may include nonlinear artifacts and unintentional microbubble destruction resulting in pseudowashout. The microbubbles themselves may result in specific artifacts such as pseudoenhancement, signal saturation, and attenuation and shadowing and can confound the use of color and spectral Doppler US. Identifying and understanding these artifacts and knowing how to mitigate them may improve the quality of the imaging study, increase user confidence, and improve patient care. The authors review the principles of UCAs and the sound-microbubble interaction, as well as the technical aspects of image generation. Technical considerations, including patient positioning, depth, acoustic window, and contrast agent dose, also are discussed. Specific artifacts are described, with tips on how to identify and, if necessary, apply corrective measures, with the goal of improving examination quality. © RSNA, 2022 Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Popcorn Appearance of Severely Calcified Uterine Leiomyoma: Image-Pathological Correlation

Calcified subserous leiomyoma is a rare benign tumor commonly seen in the postmenopausal age group. Cases with severely calcified degeneration all over the mass are extremely rare. It causes diagnostic confusion with the solid calcified adnexal mass and the large bladder calculi in the pelvis. We hereby present a case of heavily calcified subserous uterine leiomyoma in a 66-year-old postmenopausal woman. An X-ray of the abdomen and pelvis and CT scan showed a pelvic mass with scattered popcorn appearance in the pelvis, representing severely calcified discrete spots all over the mass. Sonographically, different from typical uterine leiomyomas which exhibit recurrent refractory shadowing patterns, our case showed heavy homogeneous acoustic shadow obscuring all structures beneath the mass surface, resulting in a suboptimal ultrasound examination. Accordingly, CT scans, which are usually not a primary tool for the diagnosis of uterine leiomyomas, are helpful to characterize the mass and identify their organ of origin. The case presented here was treated with a hysterectomy with bilateral oophorectomy and was post-operatively confirmed for severely calcified subserous leiomyomas.

A rare case of colonic diverticulum in a Bitch.

Colonic diverticulum is one of the rare findings in dogs characterized by an out-pouching of mucosal and submucosal layers through the defect in muscularis layer of the colon. A five years old intact female Labrador was presented with an anamnesis of dyschezia and tenesmus. Rectal examination was normal, and the survey radiograph showed an almost crescent shaped abnormal dilatation (10.52 cm × 6.21 cm) with gas and increased radiopaque material, dorsal to the urinary bladder and ventral to the descending colon suggesting fecal stasis. Ultrasonographic examination revealed gas-filled out-pouching with hyperechoic colon wall and acoustic shadowing. Exploratory celiotomy confirmed the diagnosis of colonic diverticulum, and diverticulectomy was performed. All four layers of the colonic wall were detected histopathologically in the biopsy sample and excluded neoplasia. The dog recovered uneventfully with no post-operative complications. This surgery produced an excellent resolution of clinical signs. To our knowledge, this is one of the few cases of colonic diverticulum reported in dogs.

Clinics in diagnostic imaging (216).

Clinics in diagnostic imaging (216).

Associated ultrasound findings improve the accuracy of twinkling artifacts in kidney stone diagnosis

Background: Twinkling artifact (TA) in color Doppler ultrasound is commonly used as a sign of kidney tract stone detection but the accuracy is limited as compared with unenhanced computed tomography (CT). Objective: Define the associated ultrasound findings that may improve the accuracy of TA compared with CT for diagnosing kidney stones. Materials and Methods: Prospective study was conducted on 128 TAs in patients sent for unenhanced CT KUB and performed color Doppler ultrasound on the same day. TA sizes and associated sonographic signs were recorded and analyzed with receiver operating characteristic curves (ROCs). The diagnostic reference was the CT scan. Results: There was a total of 128 TAs with the size of 3.95 mm (2.7-6 mm). Only 30 TAs showed as kidney stones in CT. The sizes of kidney stones in CT were 5.4 mm (3.4-6.4 mm) which represented a significant difference in TA size (P = 0.002). ROC curve analysis showed that 5 mm would be the optimal size of TA for kidney stone predictions. Other significant signs for improved diagnosis include echoic foci (P = 0.039), posterior shadows (P = 0.001), long TA tails (P = 0.001) and 2nd approach TA (P = 0.001). Then a predictive AT model was created to predict kidney stones, which moderately improved diagnosis accuracy for kidney stones with good agreement. Conclusion: The combination of TA and other sonographic signs are moderately associated with kidney stone diagnosis including TA size (&gt; 5 mm), posterior acoustic shadow, long TA tail, junctional line location and focal Caliectasis.

Research on the Archaeoacoustic Simulation of Daxiong Main Halls in Chinese Buddhist Temples Through Comsol Tool

The acoustic analysis plays an irreplaceable role in obtaining information on Chinese Buddhist main halls tradition and relative practice that includes sound, deepening our comprehension of Chinese Buddhist architectural heritage. Various ceremonies and dojos constitute rich types of Buddhist main halls’ sound fields. In this paper, the indoor sound fields of four main halls in the Buddhist temples are researched and compared. This paper used Sketchup to build the models and simulate sound fields when conducting ceremonies and dojos using Comsol Multiphysics software. The four main halls are Chongshan temple main hall, Xiantong temple main hall, Shuxiang temple Manjusri hall and Bodhisattva Top main hall, which are located in separately four temples of Shanxi Wutai mountain in China. Targeting three acoustic parameters including the reverberation time(RT), the first ray arrival time(Re1first) and surface sound pressure level(SPL) distribution, we simulated the acoustic effect of the space occupancy, Buddha realm space and worship space, indicating that the acoustic wave diffusion rate was positively correlated with proportion of hall height to depth, while the first arrival time is exactly the opposite. The largest RT at 2000Hz(about 1.3s)in the shortest period for 500Hz voice was observed in the main hall of Pusa Peak, while T60 even reached 4s in Xiantong temple main hall. The acoustic wave transmission rate was positively correlated with proportion of hall’s height to depth, but the first ray arrival time was the opposite. The main hall of Pusa Peak had the shortest (0.0150s) first ray arrival time，the Shuxiang temple main hall had the longest time(0.0381s). In all the cases, appearing of the "sound shadow area" of the surface SPL distribution and the uneven sound energy distribution showed pillars in the middle space exerting significant impact on the acoustics of the Daxiong main hall.

Demonstration of Fat Properties in Diagnostic Ultrasound Images through the Development of a Modular Phantom

The proportion of fat content in the body is important in the classification and grading of disease. In a clinical situation, the image characteristics of adipose tissue are used as information in diagnosing disease. Therefore, the imaging characteristics of adipose tissue on ultrasound images should be understood in a comprehensive manner. In this study, we describe the imaging characteristics of adipose tissue using ultrasound phantoms representing three different fat fractions. The three fat fractions were 0%, 40%, and 80%, and the phantoms consisted of agarose gel containing either distilled water or one of two emulsions. To characterize the fat content, the gel phantoms were scanned using an Accuvix V10 ultrasound system. Both the brightness of the ultrasound image and the attenuation of the ultrasound echo increased with increasing fat content. Deep structures could not be observed clearly in areas with high fat content. Both pure water and fat appeared to be echo-free. Pure water displayed acoustic enhancement, while fat displayed acoustic shadowing. However, the emulsion appeared to be hyperechoic because of the difference in acoustic impedance between water and fat. The results show that well-characterized fat fraction images can potentially be used to understand the characteristics of adipose tissue human body on ultrasound.

Lower extremity puncture wound.

A 58-year-old woman presented with pain after sustaining a right foot wound from a damaged wooden floor. Physical examination was remarkable for a 0.3-cm puncture wound between the first webspace on the plantar aspect of the foot with tenderness to palpation, but no visible or palpable foreign body. Plain radiographs were negative, and computed tomography of the foot noted the small puncture wound with a proximally extending linear tract. Orthopedic surgery was consulted but did not appreciate any foreign body and thus recommended conservative management without wound exploration in the emergency department (ED). Bedside ultrasound was then performed by emergency physicians that visualized a linear 4-cm hyperechoic foreign body with posterior acoustic shadowing (Figure 1, Video 1). Ultrasound-guided deep peroneal and posterior tibial nerve blocks were performed for anesthesia (Video 2). Under ultrasound guidance, curved forceps were used to grasp and remove a large wooden fragment (Figure 2, Video 3). The patient was discharged with oral antibiotics. Traumatic wounds are responsible for 11 million ED visits annually, and foreign bodies are involved in 7% to 15%.1 Many foreign bodies are missed on initial evaluation, and because of their risk for complications, they are frequently implicated in malpractice litigation.2 Plain film radiographs are considered first line and detect 80% of all foreign bodies but have a mere sensitivity of 15% for radiolucent objects, such as wood or other vegetative material.1, 3 Therefore, multimodal imaging is frequently necessary. Ultrasonography, performed in the ED setting, has an overall sensitivity and specificity of 91% for identifying foreign bodies.2 These will appear hyperechoic and may have additional clues, such as posterior acoustic shadowing, reverberation artifact, or hypoechoic halo. Using ultrasound to guide percutaneous foreign body removal can increase success in the ED to nearly 100%.4 Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.