In 2009, Hitachi commercialized “Mappie^*1, the world’s first Capacitive Micro-machined Ultrasound Transducer (CMUT) using semiconductor based technology. It generated high quality diagnostic images of mammary glands, thanks to its broad-band characteristics^[1]. This year, the 4^th generation CMUT (4G CMUT) “SML44” has been brought to the market, achieved using advanced design and precise control of the fabrication process. When combined with new imaging technologies avail-able with the ARIETTA^*2 850, the SML44, in addition to excellent image quality, offers commonly used modalities and func- tions such as Tissue Harmonic Imaging (THI), Color Flow Mapping (CFM), Real-time Tissue Elastography^*3 (RTE), and Real-time Virtual Sonography^*4 (RVS). This report introduces the latest technology adopted in the 4G CMUT design.

Objectives: To investigate the causes, differential diagnosis, and clinical significance of absent blood flow (ABF) in the testis detected by color Doppler ultrasound (CDU) in acute scrotum.
Methods: A total of 263 patients with ABF in the testis detected by CDU in our hospital were reviewed retrospectively. However, only 111 patients who underwent surgery were included in this study. The ultrasonographic features of the testis and paratesticular tissue were analyzed. The surgical or surgical-pathologic results were taken as the reference standard to determine the causes of ABF in the testis.
Results: The causes of ABF in the testis were testicular torsion (n = 98, torsion group) and non-testicular torsion related diseases (n = 13, non-torsion group, including 8 testicular rupture, 3 epididymitis-orchitis combination with testicular necrosis, and 2 tumors). Tunica albuginea of the testis, diffuse enlarged epididymis, whirlpool sign, and internal echo of the testis were the better parameters for diagnosing the causes of ABF in the testis detected by CDU. And the accuracies of these approaches were 93.7%, 91%, 83.8%, and 81.1%, respectively. Whirlpool sign had a 100% positive predictive value (PPV), and disrupted tunica albuginea of the testis and diffuse enlarged epididymis each had 100% specificity for predicting testicular torsion. When the ultrasonographic findings were combined with these methods to determine the causes, the accuracy was 96.4% (107/111).
Conclusion: ABF in the testis detected by CDU is not always indicative of testicular torsion in acute scrotum; Analyzing ultrasound findings of the testis and paratesticular tissue can help with differential diagnosis of the causes of ABF in the testis and guide clinical decision-making.

Ultrasound has developed as an invaluable tool in diagnosis and proper management in the intensive care unit (ICU). Application of critical care ultrasonography is quite distinct from the routine comprehensive diagnostic ultrasound exam, because the urgent setting mandates a goal-directed approach. Performing accurate and efficient critical care ultrasound requires ultrasound providers to first understand the pathophysiology of the disease and related imaging findings, and then follow the protocols to perform a focused ultrasound exam. In the ongoing coronavirus disease 2019 (COVID-19) pandemic, ultrasound plays an essential role in diagnosing and monitoring critically ill COVID-19 patients in the ICU. Our review focuses on the basics and clinical application of critical care ultrasound in diagnosing common lung disease, COVID-19 pulmonary lesions, pediatric COVID-19, and cardiovascular dysfunction as well as its role in ECMO and interventional ultrasonography.

Ultrasound (US) technology, with major advances and new developments, has become an essential and first-line imaging modality for clinical diagnosis and interventional treatment. US imaging has evolved from one-dimensional, two-dimensional to three-dimensional display, and from static to real-time imaging, as well as from structural to functional imaging. Based on its portability and advanced digital imaging technique, US was first adopted by emergency medicine in the 1980s and gradually gained popularity among other specialists for clinical diagnosis and interventional treatment. Point-of-Care Ultrasound (POCUS) was then proposed as a new concept and developed for new uses, which greatly extended clinical US applications. Nowadays, artificial intelligence (AI), cloud computing, 5G network, robotics, and remote technologies are starting to be integrated into US equipment. US systems have gradually evolved to an intelligent terminal platform with powerful imaging and communication tools. In addition, specialized US machines tend to be more suitable and important to meet increasing demands and requirements by various clinical specialties and departments. In this article, we review current US technology and POCUS as new concepts and its future trends, as well as related technological developments and clinical applications.

Contrast-enhanced ultrasound (CEUS) applications in cancer management have expanded over the past two decades. Through detection of vascularization and perfusion changes, CEUS provides a potentially reliable means of early prediction of response to different cancer therapies including systemic chemotherapy and locoregional therapies. Ultrasound-induced cavitation of contrast agents has a range of effects on the surrounding microenvironment. These effects can be manipulated to sensitize the tumors to radio- and chemotherapy, as well as achieve targeted delivery through drug-loaded contrast agents. Newer forms of drug carriers are being developed with improved drug-carrying capacity and tissue penetration. This review aims at providing a synopsis of the latest developments in CEUS’ use in oncologic therapy. While the majority of work described in this review is still in the pre-clinical phases, results have been encouraging and show potential translational benefit for cancer patients in the near future.

The spread of new coronavirus (SARS-Cov-2) follows a different pattern than previous respiratory viruses, posing a serious public health risk worldwide. World Health Organization (WHO) named the disease as COVID-19 and declared it a pandemic. COVID-19 is characterized by highly contagious nature, rapid transmission, swift clinical course, profound worldwide impact, and high mortality among critically ill patients. Chest X-ray, computerized tomography (CT), and ultrasound are commonly used imaging modalities. Among them, ultrasound, due to its portability and non-invasiveness, can be easily moved to the bedside for examination at any time. In addition, with use of 4G or 5G networks, remote ultrasound consultation can also be performed, which allows ultrasound to be used in isolated medial areas. Besides, the contact surface of ultrasound probe with patients is small and easy to be disinfected. Therefore, ultrasound has gotten lots of positive feedbacks from the frontline healthcare workers, and it has played an indispensable role in the course of COVID-19 diagnosis and follow up.

This case report describes a patient with severe coronavirus disease 2019 (COVID-19) concomitated with spontaneous pneumothorax, along with retrospective analysis of effective diagnosis and treatment. The case shows how chest radiography and computed tomography can play an important role in diagnosing and providing useful information for clinical management. The patient’s outcome and prognosis was related to his clinical management. In particular, early comprehensive treatment was certainly key to reducing complications and mortality in severe novel coronavirus pneumonia.

Real-time ultrasound imaging has been used for the evaluation of pulmonary abnormalities and other complications during the outbreak of COVID-19. However, conventional ultrasound examination requires operators to conduct scanning either in the examination room or patient ward, which may increase the potential infective risk. Tele-operated ultrasound robotics can provide a unique technique for doctors to remotely scan patients. During the COVID-19 pandemic, we attempted to apply a 5G network-based scanning robot to conduct remote ultrasound examination on COVID-19 patients and to explore the feasibility of this technique for teleultrasound diagnosis and consultation during critical infectious situations.

Objective: To investigate the value of lung ultrasound (LUS) in asymptomatic patients with confirmed COVID-19.
Methods: A retrospective analysis was performed on nine patients in a designated isolation hospital in Sanya from February 22nd, 2020 to February 23rd, 2020. All patients were confirmed with COVID-19 pneumonia by PCR test, but none had the typical symptoms of COVID-19. All patients first underwent LUS examination and then chest computed tomography (CT) scanning. The application value of LUS in asymptomatic confirmed patients with COVID-19 was evaluated, compared with chest CT which was regarded as the golden standard.
Results: Among nine asymptomatic patients with COVID-19, there were two cases (22.22%) with abnormal ultrasonic manifestations, of which one (11.11%) showed a fusion B3-line in zone 5 of the right lung, and the other showed localized pulmonary consolidation in zone 6 of the left lung. The remaining seven cases (77.78%) showed no abnormal changes in LUS, but only clear pleura sliding sign and A-line. Chest CT showed abnormal changes in three cases (33.33%). Two of them (22.22%) showed flocculent high-density shadow at the base of both lungs (especially in the right lung), while the other case showed ground-glass opacity with thickened interlobular septal in the left lower lobe, involving the pleura. There were no abnormalities on chest CT of the remaining six cases (66.67%). The two (22.22%) LUS-positive patients were in complete coincidence with CT-positive patients. This study showed that the coincidence rate of the two examination methods was 88.89%. Taking chest CT as golden standard, the sensitivity, specificity, positive predictive value, negative predictive value, and Kappa value of lung ultrasound in the diagnosis of COVID-19 were 66.67%, 100%, 100%, 85.71%, and 0.727, respectively.
Conclusion: LUS can evaluate lung lesions in asymptomatic patients with COVID-19. Compared with chest CT, the diagnostic coincidence rate and diagnostic consistency of LUS are relatively higher. For this asymptomatic type of patient, ultrasound can be used as a diagnosis method, which can avoid the risk of radiation exposure in a short period of time. As a rapid and dynamic assessment method, LUS can cooperate with remote consultation to provide timely and accurate guidance for clinical diagnosis and treatment when necessary.

Objective: This study evaluated the performance of automated machine-learning to diagnose non-alcoholic fatty liver disease (NAFLD) by ultrasound and compared these findings to radiologist performance.
Methods: 96 patients with histologic (33) or proton density fat fraction MRI (63) diagnosis of NAFLD and 100 patients without evidence of NAFLD were retrospectively identified. The “Fatty Liver” label included 96 patients with 405 images and the “Not Fatty Liver” label included 100 patients with 500 images. These 905 images made up a “Comprehensive Image” group. A “Radiology Selected Image” group was then created by selecting only images considered diagnostic by a blinded radiologist, resulting in 649 images. Cloud AutoML Visionbeta (Google LLC, Mountain View, CA) was used for machine learning. The models were evaluated against three blinded radiologists.
Results: The “Comprehensive Image” group model demonstrated a sensitivity of 88.6% (73.3-96.8%) and a specificity of 95.3% (84.2-99.4%). Radiologist performance on this image group included a sensitivity of 81.0% (74.3-87.6%) and specificity of 86.0% (72.6-99.5%). The model’s overall accuracy was 92.3% (84.0-97.1%), compared with mean individual performance (83.8%, 78.4-89.1%). The “Radiology Selected Image” group model demonstrated a sensitivity of 88.6% (73.3 - 96.8%) and specificity of 87.9% (71.8-96.6%). Mean radiologist sensitivity was 92.4% (86.9-97.9%) and specificity was 91.9% (83.4-100%). The model’s overall accuracy was 88.2% (78.1-94.8%) which was comparable to the individual radiologist performance (92.2%, 90.1-94.2%) and consensus performance (95.6%, 87.6-99.1%).
Conclusions: An automated machine-learning algorithm may accurately detect NAFLD on ultrasound.

The purpose of this article is to review the use of lung ultrasonography (US) in the workup of COVID-19 pneumonia. The scanning protocol, normal US appearance of lung, major US features of COVID-19 pneumonia, diagnostic performance of lung US and potential pitfalls when explaining US results are descripted and discussed. Lung US is increasingly accepted as a useful tool in the workup of COVID-19 pneumonia. Certain US imaging features allow to confirm or rule out the diagnosis for clinical management; on other hand, most US findings are nonspecific with technical limitations. Thus, it is important to recognize these drawbacks since the ignorance of potential pitfalls of lung US may lead to over diagnosis or missed diagnosis.

Ultrasound imaging has attracted great interest of researchers due to their application in cancer diagnosis and treatment. Ultrasound contrast agents, microbubbles and nanobubbles are widely explored as a multifunctional platform, not only carrying other contrast agents for multimodal imaging to complement the disadvantages of each imaging modality, but also carrying drug/gene for cancer theragnostic. In this article, the characteristics and differences of microbubbles and nanobubbles are briefly introduced and reviewed. Besides, the microbubbles and nanobubbles driven multimodal imaging and theragnostic of cancer are summarized.

Protective measures that are needed when treating patients with highly contagious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) add difficulty when performing interventional procedures in isolation wards. We describe two cases of ultrasonography-guided nasogastric tube placement in severe COVID-19 patients, both disabled elderly patients who were unconscious and had complicated underlying diseases. The first is an 83-year-old patient with Alzheimer's, hemiplegia, and epilepsy; the second is a 67-year-old patient with hemiplegia and thoracic deformity. Nasogastric tube indwelling for severe patients like this was essential but challenging. With the help of ultrasonography, intubation proceeded successfully and rapidly. Operator’s confidence of appropriate placement was established because of definite tube visualization. These cases demonstrated that bedside ultrasonography in isolation wards can not only facilitate diagnosis but also assist interventional operations.

Objectives: To investigate the clinical value of ultrasound in the diagnosis and treatment of reninoma.
Methods: We retrospectively analyzed the ultrasound findings of 9 patients with reninoma confirmed by pathology after surgical resection in our hospital between September 2012 and August 2019. All patients underwent conventional preoperative ultrasonography. Three underwent contrast-enhanced ultrasound (CEUS) and 3 with complete endogenetic tumor underwent intraoperative ultrasonography.
Results: Of the 9 patients with conventional ultrasound, 7 had renal space-occupying lesions and 2 had missed diagnosis. A hypoechoic or hyperechoic solid mass with regular morphology, clear boundary, capsule, weak echo halo around the mass, incomplete thin strip color blood flow signal around the mass were shown in 7 cases. Color Doppler displayed color flow signal of the incomplete thin strip around the mass and arterial blood supply with an internal thin branch. In 3 patients (including 2 with missing diagnosis by conventional ultrasound) who underwent preoperative contrast-enhanced ultrasound, the reninoma manifested as low enhancement, and the perfusion pattern showed as slow wash-in and slow wash-out compared with normal renal cortex. In 3 patients (including 2 cases of missed diagnosis by conventional ultrasound) with completely endogenic reninoma, intraoperative ultrasound clearly showed the tumor characteristics, and all successfully underwent laparoscopic ultrasound-guided partial nephrectomy.
Conclusions: Preoperative conventional ultrasound combined with CEUS, and clinical features, are helpful for the qualitative diagnosis of reninoma. Laparoscopic partial resection is the first-choice treatment for reninoma. Intraoperative ultrasound can provide real-time imaging, accurately evaluate the tumor status, and provide important information for surgeons.

Contrast-enhanced ultrasound (CEUS) is an imaging modality that has achieved considerable relevance in various clinical settings including the assessment of renal disease. CEUS is performed by injecting microbubble-based ultrasound contrast agents (UCAs) that create signals to display the microvasculature, allowing quantitative and qualitative assessment of parenchymal perfusion and real-time visualization of the renal anatomy. In recent years, CEUS has been widely accepted and applied for the assessment of kidney perfusion and the characterization of indeterminate renal masses, primarily due to its diagnostic efficacy, availability, low cost, reproducibility, and absence of nephrotoxicity. CEUS provides a higher spatial and temporal resolution than other cross-sectional imaging, resulting in high sensitivity and specificity for its applications in a variety of renal conditions including cancer monitoring following ablation, detection of transplant complications, hypoperfusion, acute traumatic injury, renal artery stenosis, parenchymal infection, and kidney intervention guidance. Additionally, the continuous investigation and development of new technologies surrounding this imaging technique have shown encouraging preliminary results for the use of CEUS in the evaluation of molecular expression in several disease processes, the dynamic analysis of blood flow kinetics, and the implementation of super-resolution imaging systems. The purpose of this article is to provide an overview of the current and potential clinical applications of renal CEUS.

The Coronavirus Disease 2019 (COVID-19) has spread rapidly throughout the world. COVID-19 is a highly contagious and potentially lethal infection, and as a result, individuals infected with it are treated in isolation units. Teleultrasound (TUS), particularly with the support of the fifth generation (5G) wireless transmission technology, can provide timely monitoring, fast clinical progress assessment, and help to guide interventional produces for patients with COVID-19 in isolation units. It can also reduce the risk of medical workers infection and save medical resources such as equipment and supplies. The purpose of this paper is to present an overview of operating procedures and ongoing planning with TUS for COVID-19 patients in China.

Objective: To investigate the feasibility of evaluating imaging changes pre-and post-treatment in Corona Virus Disease 2019 (COVID-19) patients by transthoracic pulmonary ultrasound.
Methods: A total of 8 patients diagnosed with severe or critical COVID-19 pneumonia were recruited, and then ultrasound scanning was performed to evaluate the pulmonary imaging changes pre- and post-treatment based on a modified ultrasonic Buda protocol. The correlation between chest high resolution computed tomography (HRCT) Warrick scoring and ultrasonic results was analyzed.
Results: The main manifestations of ultrasonic imaging in severe or critical COVID-19 patients were: (1) pleural thickening (8/8), blurry or irregular fragmentation (6/8), and discontinuous fragmentation (4/8); (2) pulmonary lesions: B-line sign (2/8), partial or complete fusion of B-line (white lung) (8/8), and pulmonary or subpleural small consolidation (C-line sign) in severe cases (3/8); and (3) rarely, pleural effusion or pulmonary gas cyst (1/8). The imaging results, which were evaluated followed by a modified Buda transthoracic pulmonary ultrasound protocol, were highly correlated with HRCT Warrick scoring (r = 0.715, P < 0.05). Meanwhile, both ultrasonic and HRCT imaging results were significantly improved with progressive COVID-19 treatment (P < 0.05).
Conclusion: The ultrasonic pulmonary imaging of COVID-19 patients manifested several characteristics. The modified Buda transthoracic pulmonary ultrasound protocol could be an alternative method to evaluate the pulmonary lesions in COVID-19 patients.

Thyroglossal duct cyst is the most common congenital cyst, locating in the midline neck below the hyoid bone. Carcinoma occurring in a thyroglossal duct cyst is rare. Diagnosis generally depends on postoperative pathological diagnosis, because preoperative diagnosis is difficult, but imaging and fine-needle aspiration biopsy (FNAB) can help with the diagnosis. In addition, there is no consensus on the optimal management of thyroglossal duct cyst carcinoma. This paper describes a case of carcinoma in the thyroglossal duct cyst in a 60-year-old man and contains a review of the literature about the presentation, imaging manifestations and treatment.

Neuromyelitis optica spectrum disorder (NMOSD) is an idiopathic autoimmune inflammatory disorder which is characterized by central nervous system (CNS) demyelinating. Common symptoms of area postrema clinical syndrome (APS) include intractable hiccup, nausea and vomit which may lead to aspiration pneumonia. In this article, we report a patient with suspicious COVID-19 infection and complicated with NMOSD and aspiration pneumonia. The question still remains that whether 2019-nCoV could infect CNS and cause NMO.

Klippel-Trenaunay syndrome (KTS) is a rare congenital disorder. In this case study, we reported prenatal ultrasound study on a 33-year-old pregnant woman at the gestation of 26 weeks and 3 days, whose fetus was suspected of KTS associated with enlarged right thigh and dilated inferior vena cava. Additionally, we comprehensively reviewed literatures of prenatal KTS published on Medline to further understanding of the prenatal ultrasonographic manifestations of KTS.

Known for being highly sensitive and noninvasive, ultrasound imaging using microbubble contrast agents is widely used in the clinic. To use ultrasound to image tissue beyond the vasculature, researchers have developed strategies that include nanobubbles, ultrasound contrast agents generated in situ, and gene expression of ultrasound contrast agents in situ. All of these strategies offer the capability of targeting tumor cells, intratumoral imaging tumor cells and require just a small incision or no incision. In this review, we will first describe the application of nanobubbles acting as ultrasound contrast agents. Then, we will briefly introduce the stimuli-responsive formulations to generate ultrasound contrast agents in situ. Finally, we will provide an overview of the use of state-of-the-art of gene expression of ultrasound contrast agents in situ to monitor cellular location and function inside living organisms.

Objective: To investigate the application of remote ultrasound in COVID-19 isolation ward.
Methods: Two patients with suspected COVID-19 were admitted to the isolation ward in critical condition. In the isolation ward, the intensive care unit (ICU) physician used ultrasound to evaluate patients’ heart, lung, abdomen, blood volume, and lower limb veins, guided by an ultrasound expert in remote.
Results: (1) Under the guidance of the ultrasound expert, the ICU physician successfully performed ultrasound examination and gathered clear images. (2) The main manifestations of the patients’ lung lesions were multiple B3-lines in both lungs fused to “white lung” and pulmonary consolidation in the subpleural area. A small amount of effusion was observed in the bilateral costal diaphragmatic angle and left lower extremity vein thrombosis was found in patient No.1. Ultrasound was also used to assess the inner diameter and respiratory variability of the inferior vena cava for adjusting fluid supplementation. Patient No.1’s condition was severe with rapidly progressing pulmonary lesions. After treatment, ultrasound showed improvement in pneumonia and disappearance of pleural effusion and the left lower extremity vein thrombosis. (3) There was a high degree of consistency between ultrasound and chest computerized tomography (CT) findings in two patients.
Conclusion: The application of remote ultrasound can reduce the risk of cross-infection and save the personal protective equipment in the COVID-19 outbreak. Ultrasound experts can also provide real-time guidance for ICU physician to maintain a good quality of patient care and receive high-quality images for accurate diagnosis.

Phyllodes tumors of the breast are rare fibroepithelial neoplasm which are generally divided into benign, borderline, or malignant. In this case study, we reported a 40-year-old female presented with an asymptomatic right breast mass underwent sonographic evaluation. The surgical histopathology was diagnosed as borderline phyllodes tumor. Sonographic features of the tumor are described in detail, and the relevant literatures are reviewed and discussed.

Objective: To evaluate the role of ultrasound in the use and maintenance of ECMO for COVID-19 cases.
Methods: During the outbreak of COVID-19 in China, three critically ill patients were treated with ECMO in our hospital. Bedside ultrasound was used throughout all procedures, including in the delivery and daily monitoring of ECMO.
Results: Structural and functional changes of heart, pleural effusion, as well as thrombus formation in one patient’s right atrium were noted with ultrasonography. Using bedside ultrasound as a troubleshooting tool throughout ECMO therapy provided a lot of useful and reliable real-time information to assist clinical decision making.
Conclusion: Ultrasound shall play an important role in the use and maintenance of ECMO for COVID-19 cases.

Objectives: To analyze the progression manifestations and characteristics of pulmonary lesions in patients with COVID-19 by bed-side pulmonary ultrasonography.
Methods: A total of 20 COVID-19 patients admitted to the hospital from January to March in 2020 were retrospectively recruited. All cases were diagnosed according to the "Novel Coronavirus Pneumonia Treatment Protocol (Trial 7th edition)". The imaging characteristics of bed-side pulmonary ultrasonography were analyzed and summarized during the different disease stages.
Results: The average course of disease was 21.2 days, including 10.5 days of the progression period and 10.7 days of the recovery period. The ultrasound images of the patients were mainly presented as unsmoothed or interrupted pleural line, and B-line distribution was observed in all cases (20/20,100%). The "inflatable signs" in the consolidation lesion were visualized in 16 cases (16/20, 75.00%). In progressive stage, the ultrasound image changed from B-line sign to sieve-like consolidation, then the consolidation aggravated from patchy to chunk-like gradually, with the decreasing air bronchogram sign within the consolidation lesion. While the imaging characteristics of the ultrasound in the recovery stage were opposite to the progress stage, Color mode showed that the perfusion in the lesions of consolidation gradually increased as well.
Conclusion: The ultrasonic manifestations of COVID-19 patients had certain characteristics in the different disease stages. The application of ultrasound in these patients could provide imaging evidence in evaluation of the disease courses and therapeutic efficacy.

Leiomyoma, commonly known as fibroids, is a common female disease. Leiomyoma of the round ligament of the uterus is rare. Extraperitoneal leiomyoma of the round ligament can present as inguinal and vulvar mass mimicking an incarcerated hernia, lymph node, or lipomas. We are presenting a rare case of a 53-year-old female patient who was admitted to the hospital with a right inguinal mass. Our patient underwent surgery, and a leiomyoma of the round ligament was found. Before surgery, sonography and computed tomography (CT) will be helpful in the diagnosis of extraperitoneal leiomyoma of the round ligament.

Objective: The aims of the current study were to describe the serial CT characteristics of patients infected with COVID-19. In addition, in the light of the CT findings, we tried to determine whether virulence weakens during the transmission with quarantine management.
Methods: Demographics, comorbidity, clinical findings, CT scanning, and scores of the affected lung parenchyma were compared for 131 patients with abnormality on CT images classified as COVID-19 pneumonia and the patients were divided between an imported group (n = 83) and indigenous group (n = 48), according to infected location. Two reviewers scored chest CT examinations for segmental involvement, ground glass opacities, consolidation, and honeycombing opacities. The 55 patients with peak CT "severity score" were selected o make a comparative analysis.
Results: Patients’ demographics and comorbidities and clinical findings did not differ significantly between the two groups. The CT scores distribution trendline of the third CT scanning was lower than the former CT scanning. The peak CT scores trendline of the 55 selected COVID-19 patients in the indigenous group was lower than the imported group. The ROC analysis revealed an area under curve of 0.714 for the CT scanning with an optimal cutoff scores of 2.55 for prediction of contact history, a sensitivity of 76.3%, and a specificity of 52.9%.The peak CT scores of the imported cases were higher than of the indigenous cases and the lung consolidation predominance on CT findings was remarkable in the imported patients (P < 0.05).
Conclusions: CT scanning not only monitored the progression of patients with COVID-19 but also reflected their exposure status to some extent. We suggest that a follow-up CT scanning interval of more than 5 days might be cost effective. The pathogenicity of novel coronavirus may be weakened through transmission under adequate quarantine measures, since indigenous cases have much better progression than imported cases.

Objective: To investigate the diagnostic value of ultrasound-guided water enema for children with secondary intussusception.
Methods: We performed a retrospective analysis of the sonographic findings of 52 children with a confirmed diagnosis of SI through colonoscopy or surgical pathology between May 2016 and May 2019 in Shenzhen Children’s Hospital. The diagnostic value of ultrasound-guided water enema was evaluated.
Results: Of the 52 patients with SI (29 male, 23 female; average age, 50 months [range: 3 months to 12 years]), 16 had intestinal polyps, including 15 cases of juvenile polyps and 1 case of Peutz-Jeghers (P-J) polyps; 14 had Meckel's diverticulum; 11 had lymphoma; 10 had intestinal duplication; and 1 had jejunal schwannoma. All 52 patients were diagnosed with intussusception, of which 41 were confirmed with the presence of pathological lead points (PLPs) before water enema. After enema, PLP was demonstrated in 48 cases. All of the remaining 4 cases without a PLP diagnosis were found to be Meckel’s diverticulum. Ultrasonography revealed the specific features in each category. Patients with juvenile polyps showed hypoechoic masses in the intestinal lumen and some honeycomb-like anechoic masses while the single P-J polyp case showed hypoechoic masses with branching echoes in the intestinal lumen. Three of the Meckel’s diverticula cases showed irregular hyperechoic masses inside the intussusception, and 7 showed cystic masses inside the intussusception. All 11 lymphomas cases showed extremely hypoechoic masses. All 10 intestinal duplication cases showed cystic masses at the neck or inside the intussusception, with walls exhibiting intestinal wall-like structure. The case of jejunal schwannoma showed irregular hypoechoic masses at the neck of the intussusception. There were no major complications such as intestinal perforation occurred in all the children after the completion of water enema ultrasound examination.
Conclusion: Ultrasound-guided water enema helps identify PLPs and improves the diagnosis of primary diseases in children with SI.

The ultrasound contrast agents currently used in clinics are microbubbles with a large particle size and short circulation time, and their approved clinical applications are limited to endovascular diagnosis and therapy only. The development of ultrasound-responsive nanodroplets (NDs) provides a new approach for extravascular diagnosis and therapy, especially for molecular imaging and targeted therapy of tumors. The NDs with a nano-scaled particle size and a liquid core can maintain their shape and initial diameter during injection, enhancing their EPR effects and facilitating the accumulation of NDs at the tumor site. When exposed to ultrasound, NDs can vaporize and exhibit contrast enhancement at the sites of interest. In addition, the destruction of microbubbles can provide a driving force to facilitate the release of drugs or genes from the microbubbles into target cells, allowing the NDs to act as drug carriers. The development of ultrasound-responsive NDs has shown rapid progress in recent years, while a variety of NDs with excellent properties have been fabricated for targeted diagnosis and drug delivery. In this article, the development of ultrasound-responsive NDs was reviewed in terms of their structure, phase transition properties, and applications in targeted tumor diagnosis and therapy.

Upper gastrointestinal (GI) abnormalities are one of the most common disease in clinical practice, and among them, gastric cancer is one of the most common causes of cancer-related death in China. However, conventional trans-abdominal ultrasound is difficult to evaluate GI diseases due to gas filled in the GI tract. With the development of oral contrast agents in China, ultrasonography with oral contrast agent has been used to visualize upper GI tract (i.e., stomach and duodenum) as well as its surrounding structures. The primary purposes of this consensus and guideline written by Chinese experts is to provide a coherent and clinical perspectives and practical protocol for using oral contrast in upper GI ultrasound, including four components: (1) indications and contraindications of gastric contrast ultrasound; (2) patients and instruments preparation; (3) scanning technique and imaging acquisition; (4) diagnosis of upper GI abnormalities.

Objective: To assess the value of ultrasound images and reports scoring system for quality control in clinical ultrasound practice.
Methods: Ultrasound images and reports scoring system was established and implemented in the Department of Medical Ultrasound at West China Hospital of Sichuan University in 2014. The scoring system along with formulated corresponding management measures was used for quality control of ultrasound examination and clinical practice assessment. The quantitative scoring results were summarized and analyzed.
Results: Through the quantitative assessment of the quality of the images and reports of ultrasound examinations, the total report score in our department had risen from 4.93 in 2014 to 4.98 in 2018. “Inconsistency between description and conclusion” accounted for 46.47% of all report errors, which was the most common report error. The total image score also increased slightly to ≥ 4.98 during the past three years. The most common image error was “not saving color Doppler images”, which accounted for 84.48% of all image errors. The total score of images was higher than that of text reports.
Conclusion: It is important to establish the ultrasound images and reports scoring system for quality control of ultrasound practice. Using quantitative scores for ultrasound images and reports can improve the quality control of ultrasound examination and strengthen the management of clinical operation.

For symptomatic hypertrophic obstructive cardiomyopathy (HOCM), how to effectively relieve left ventricular outflow tract obstruction is of great significance. Relying on drugs and double-chamber pacing to reduce left ventricular outflow tract pressure gradient can alleviate symptoms. Methods to reduce the thickness of inter-ventricular septum include myocardial myectomy, percutaneous transluminal septal myocardial ablation, radiofrequency catheter ablation of ventricular tachycardia, and high-intensity focused ultrasound (HIFU) ablation of the ventricular septum that were performed on animal experiments to reduce inter-ventricular septal thickness, and showed significant therapeutic effects. Ultrasound-guided percutaneous intramyocardial septal ablation, as a less invasive and more effective treatment, exhibited great application prospects in reducing the pressure gradient of left ventricular outflow tract. This article reviews the research progress of several ventricular septal ablation techniques for the treatment of HOCM.

Gas therapy is a new therapeutic method that has been developed in recent years and shows great clinical prospects for the treatment of tumours and cardiovascular, nerve, and immune system diseases. Therapeutic gases, including oxygen, hydrogen, nitric oxide, hydrogen sulfide, xenon, and other bioactive gases are involved in modulating cell signaling pathways and have important physiological functions with substantial therapeutic potential. However, their precise delivery remains a major challenge. Recently, researchers began to use ultrasound to trigger microbubbles that have encapsulated these gases for intravenous administration. This not only enhances the contrast of ultrasound imaging, but also precisely releases gases in the targeted area using ultrasound-targeted microbubble destruction. This article reviews the latest advances in the use of microbubbles to load therapeutic gases for the treatment of diseases.

Objectives: To determine the efficacy of Doppler-based renal resistive index (RRI) in the prediction of acute kidney injury (AKI) in critically ill patients.
Methods: A systematic review and meta-analysis of cohort studies was conducted. Relevant studies were identified in PubMed, Embase and Cochrane Library from inception to November 1, 2020, and reference lists of identified primary studies. Prospective studies that examined the diagnostic accuracy of RRI in AKI were included.
Results: Among the 126 articles identified, 18 were included, with a total of 1656 patients. Bivariate analysis yielded pooled sensitivity and specificity of 0.81 (95% CI 0.74-0.86) and 0.75 (95% CI 0.65-0.83), respectively. The summary positive likelihood ratio was 3.2 (95% CI 2.2-4.6), and negative likelihood ratio was 0.26 (95% CI 0.19-0.36).
Conclusion: Elevated RRI may be an early predictor of AKI in critically ill patients. Further large-scale prospective studies are needed to confirm the predictive efficacy and determine the performance and optimal cutoff value of RRI among the included studies.

The study aims to review literatures on ultrasound-based radiomics, including ultrasound modalities, and discusses basic methods, applications, and limitations of ultrasound-based radiomics. The search strategy was conducted in form of “Radiomics [Title/Abstract] and Ultrasound [Title/Abstract]”in PubMed. The retrieved articles were initially screened via abstracts. Then, the main objectives, methods, and achievements of selected articles were summarized. Finally, twenty articles focused on malignancies of different organs, such as liver, rectum, breast, and thyroid were included into this review. The multiparametric features exhibited a superior diagnostic performance compared with a single modality. Ultrasound-based radiomics can assist radiologists to improve the accuracy of diagnosis, and it may promote the development of precision diagnosis and treatment of various types of cancer.

Chronic liver disease is common in China and worldwide, with liver fibrosis as the primary pathological finding. Any chronic liver disease can lead to hepatic fibrosis and gradually develop into cirrhosis. Complications, such as portal hypertension, gastrointestinal bleeding, and liver failure can occur. Some patients even develop hepatocellular carcinoma. Thus, timely diagnosis of hepatic fibrosis is vital for the assessment of etiology, treatment, and prognosis. Conventional ultrasound imaging shows low sensitivity with its subjectivity for preliminary diagnosis of liver fibrosis, creating limitations in qualitative and quantitative evaluation. Ultrasound elastography is a recently developed technique that can help overcome these limitations. The elastic imaging method combines conventional ultrasound to assess liver stiffness along with routine examination. This "one-stop" check for liver disease opens new prospects for clinical and scientific research and improves the accuracy of disease diagnosis for broad clinical application. This article will review the current status of ultrasound elastography for its applications in chronic liver diseases.

Objective: To compare the etiologies and adverse outcomes of pregnancies with short fetal femur length (FL) categorized based on relative proportion and percentile placement.
Methods: Fetuses (n = 254) with short FL measured by ultrasound were classified into four groups: severe and disproportionate short FL (group A); severe and proportionate short FL (group B); mild and disproportionate short FL (group C); mild and proportionate short FL (group D). Etiologies and outcomes of pregnancies were compared between groups.
Results: A larger percentage of skeletal dysplasia occurred in group A (28.57%) than in the other three groups (group B: 1.85%; group C: 4.08%; group D: 0). Groups A and B also had higher rates (group A: 40.82%, group B:33.33%) of fetal growth restriction (FGR) than groups C and D (group C: 4.08%; group D:3.92%). No difference in chromosomal and genetic anomalies was detected among groups (P = 0.307); however, the rate of chromosomal and genetic testing in group A was higher than in group D (P = 0.001). Group A (57.14%) had a significantly lower rate of live birth than the other three groups, and group D (98.04%) had a higher live birth rate than groups B (87.04%) and C (83.67%). Considering only living fetuses, higher rates of preterm birth (P < 0.001), low birth weight (LBW) (P < 0.001), neonatal intensive care unit (NICU) admission or pediatric hospital referral (P = 0.004), Apgar score (1 min/5 min) ≤7 (P < 0.001) and fetal distress or neonatal asphyxia (P = 0.004) were found in group A compared to group D.
Conclusion: Fetuses with severe and disproportionate short FL should be flagged for possible skeletal dysplasia. Fetuses with severe short FL should be watched for FGR prenatally. Invasive prenatal tests are recommended for fetuses with severe and disproportionate FL but not recommended for those with mild and proportionate short FL. Outcomes of fetuses with severe and disproportionate short FL were worse than that of fetuses with mild and proportionate short FL.

Objective: To discuss the value of bedside ultrasound in the diagnosis and treatment of 2019 novel coronavirus diseases (COVID-19).
Methods: Retrospective analysis of the results of bedside ultrasound of 510 patients with COVID-19 in our hospital was done from January 31, 2020 to March 4, 2020.
Results: (1) Among the 510 patients who underwent bedside ultrasound examination, a total of 327 (64.1%) underwent echocardiography, 494 (96.9%) underwent bilateral venous ultrasound examination of lower limbs, 86 (16.9%) underwent bilateral artery ultrasound examination of lower limbs, 48 (9.4%) underwent ultrasound examination of liver, gallbladder, spleen and pancreas, 26 (5.1%) underwent ultrasound examination of kidney, ureter and bladder, and the numbers of patients who underwent ultrasound examination of pericardium, pleural effusion, and peritoneal effusion were 16 (3.1%), 21 (4.1%), and 5 (1%), respectively. (2) Among the 327 patients who underwent bedside ultrasound examination of the heart, 96 (29.4%) showed results of positive for other abnormalities or complications, in which 31 (9.5%) had abnormal left ventricular wall motion, 42 (12.8%) were with valvular heart disease, 3 (0.9%) showed coronary heart disease, 19 (5.8%) showed the enlargement of right heart with pulmonary hypertension (PAH), and 1 (0.3%) had congenital heart disease. In addition, 6 of the 327 echocardiography patients showed negative results (no other abnormalities or complications), accounting for 1.8%. (3) Among the 494 patients who underwent bilateral venous examination of lower limbs, 182 (36.8%) had phlebothrombosis. Eighty-six (86) patients underwent bilateral artery examination of lower limbs, and 63 (73%) of them had positive results, in which 5 patients showed arterial occlusion and the other 57 patients showed atherosclerosis. (4) Thirty-three (33) patients underwent ultrasound examination of liver, gallbladder, spleen, and pancreas, and 23 (70%) of them showed positive results. Among the 26 patients who underwent the urological examination, 7 (26.9%) showed positive results. Additionally, there are 2 positive findings in 21 patients who underwent the examination of pleural effusion (9.5%), and 1 positive case in 5 patients who underwent the examination of abdominal effusion (20%).
Conclusion: Bedside ultrasound is important in the diagnosis and treatment of COVID-19. We hope to make better use of bedside ultrasound to help clinicians get accurate diagnosis and treatment strategies.