A shock flash breaking out of a dusty red supergiant.

Shock-breakout emission is light that arises when a shockwave, generated by the core-collapse explosion of a massive star, passes through its outer envelope. Hitherto, the earliest detection of such a signal was at several hours after the explosion1, although a few others had been reported2-7. The temporal evolution of early light curves should provide insights into the shock propagation, including explosion asymmetry and environment in the vicinity, but this has been hampered by the lack of multiwavelength observations. Here we report the instant multiband observations of a type II supernova (SN 2023ixf) in the galaxy M101 (at a distance of 6.85 ± 0.15 Mpc; ref. 8), beginning at about 1.4 h after the explosion. The exploding star was a red supergiant with a radius of about 440 solar radii. The light curves evolved rapidly, on timescales of 1-2 h, and appeared unusually fainter and redder than predicted by the models9-11 within the first few hours, which we attribute to an optically thick dust shell before it was disrupted by the shockwave. We infer that the breakout and perhaps the distribution of the surrounding dust were not spherically symmetric.

The nature of an ultra-faint galaxy in the cosmic dark ages seen with JWST.

In the first billion years after the Big Bang, sources of ultraviolet (UV) photons are believed to have ionized intergalactic hydrogen, rendering the Universe transparent to UV radiation. Galaxies brighter than the characteristic luminosity L* (refs. 1,2) do not provide enough ionizing photons to drive this cosmic reionization. Fainter galaxies are thought to dominate the photon budget; however, they are surrounded by neutral gas that prevents the escape of the Lyman-α photons, which has been the dominant way to identify them so far. JD1 was previously identified as a triply-imaged galaxy with a magnification factor of 13 provided by the foreground cluster Abell 2744 (ref. 3), and a photometric redshift of z ≈ 10. Here we report the spectroscopic confirmation of this very low luminosity (≈0.05 L*) galaxy at z = 9.79, observed 480 Myr after the Big Bang, by means of the identification of the Lyman break and redward continuum, as well as multiple ≳4σ emission lines, with the Near-InfraRed Spectrograph (NIRSpec) and Near-InfraRed Camera (NIRCam) instruments. The combination of the James Webb Space Telescope (JWST) and gravitational lensing shows that this ultra-faint galaxy (MUV = -17.35)-with a luminosity typical of the sources responsible for cosmic reionization-has a compact (≈150 pc) and complex morphology, low stellar mass (107.19 M⊙) and subsolar (≈0.6 Z⊙) gas-phase metallicity.

Correlating concerted cations with oxygen redox in rechargeable batteries.

Rechargeable batteries currently power much of our world, but with the increased demand for electric vehicles (EVs) capable of traveling hundreds of miles on a single charge, new paradigms are necessary for overcoming the limits of energy density, particularly in rechargeable batteries. The emergence of reversible anionic redox reactions presents a promising direction toward achieving this goal; however this process has both positive and negative effects on battery performance. While it often leads to higher capacity, anionic redox also causes several unfavorable effects such as voltage fade, voltage hysteresis, sluggish kinetics, and oxygen loss. However, the introduction of cations with topological chemistry tendencies has created an efficient pathway for achieving long-term oxygen redox with improved kinetics. The cations serve as pillars in the crystal structure and meanwhile can interact with oxygen in ways that affect the oxygen redox process through their impact on the electronic structure. This review delves into a detailed examination of the fundamental physical and chemical characteristics of oxygen redox and elucidates the crucial role that cations play in this process at the atomic and electronic scales. Furthermore, we present a systematic summary of polycationic systems, with an emphasis on their electrochemical performance, in order to provide perspectives on the development of next-generation cathode materials.

Design, synthesis, in vitro and in vivo biological evaluation of pterostilbene derivatives for anti-inflammation therapy.

Pterostilbene (PST) is a naturally derived stilbene compound in grapes, blueberries, and other fruits. It is also a natural dietary compound with a wide range of biological activities such as antioxidant, anti-inflammatory, antitumor, and so on. Structural modifications based on the chemical scaffold of the pterostilbene skeleton are of great importance for drug discovery. In this study, pterostilbene skeletons were used to design novel anti-inflammatory compounds with high activity and low toxicity. A total of 30 new were found and synthesised, and their anti-inflammatory activity and safety were screened. Among them, compound E2 was the most active (against NO: IC50 = 0.7 µM) than celecoxib. Further studies showed that compound E2 exerted anti-inflammatory activity by blocking LPS-induced NF-κB/MAPK signalling pathway activation. In vivo experiments revealed that compound E2 had a good alleviating effect on acute colitis in mice. In conclusion, compound E2 may be a promising anti-inflammatory lead compound.

Assessment of the Diagnostic Performance of Clinical Examinations and High-Frequency Ultrasound in Patients With Pigmented Skin Tumors.

OBJECTIVES: To investigate whether the integration of high-frequency ultrasound (HFUS) to routine clinical examinations could improve diagnostic performance and management decision for pigmented skin tumors. METHODS: Three general practitioners trained previously and a dermatologist independently assessed pigmented skin tumors and rendered management decision based on clinical examinations alone or clinical examinations integrating HFUS. RESULTS: After integrating HFUS, the diagnostic area under the curve (AUC) (0.658-0.693 versus 0.848, all P < .05) and specificity (46.6-58.6% versus 89.7%, all P < .05) for pigmented skin malignancies were improved for general practitioners, meanwhile unnecessary biopsy rate reduced (42.9-53.6% versus 10.7%, P < .001). To the dermatologist, the diagnostic AUC (0.822 versus 0.949, P < .001), sensitivity (81.7% versus 96.7%, P = .012) and specificity (0.828 versus 0.931, P = .031) improved significantly, meanwhile both missed biopsy rate (14.5% versus 4.8%, P = .031) and unnecessary biopsy rate (19.6% versus 7.1%, P = .016) decreased. Additionally, the diagnostic performance of the general practitioner with integrating HFUS could be comparable with the dermatologist based on clinical examinations alone (all P > .05). CONCLUSIONS: As a complementary tool of clinical examinations, HFUS could help physicians differentiate pigmented skin malignancies and manage decision.

Cobalt-Catalyzed Diastereo- and Enantioselective Carbon-Carbon Bond Forming Reactions of Cyclobutenes.

Catalytic enantioselective functionalization of cyclobutenes constitutes a general and modular strategy for construction of enantioenriched complex cyclobutanes bearing multiple stereogenic centers, as chiral four-membered rings are common motifs in biologically active molecules and versatile intermediates in organic synthesis. However, enantioselective synthesis of cyclobutanes through such a strategy remained significantly limited. Herein, we report a series of unprecedented cobalt-catalyzed carbon-carbon bond forming reactions of cyclobutenes that are initiated through enantioselective carbometalation. The protocols feature diastereo- and enantioselective introduction of allyl, alkynyl, and functionalized alkyl groups. Mechanistic studies indicated an unusual 1,3-cobalt migration and subsequent ß-carbon elimination cascade process occurred in the allyl addition. These new discoveries established a new elementary process for cobalt catalysis and an extension of diversity of nucleophiles for enantioselective transformations of cyclobutenes.

Risk stratification of gallbladder masses by machine learning-based ultrasound radiomics models: a prospective and multi-institutional study.

OBJECTIVE: This study aimed to evaluate the diagnostic performance of machine learning (ML)-based ultrasound (US) radiomics models for risk stratification of gallbladder (GB) masses. METHODS: We prospectively examined 640 pathologically confirmed GB masses obtained from 640 patients between August 2019 and October 2022 at four institutions. Radiomics features were extracted from grayscale US images and germane features were selected. Subsequently, 11 ML algorithms were separately used with the selected features to construct optimum US radiomics models for risk stratification of the GB masses. Furthermore, we compared the diagnostic performance of these models with the conventional US and contrast-enhanced US (CEUS) models. RESULTS: The optimal XGBoost-based US radiomics model for discriminating neoplastic from non-neoplastic GB lesions showed higher diagnostic performance in terms of areas under the curves (AUCs) than the conventional US model (0.822-0.853 vs. 0.642-0.706, p < 0.05) and potentially decreased unnecessary cholecystectomy rate in a speculative comparison with performing cholecystectomy for lesions sized over 10 mm (2.7-13.8% vs. 53.6-64.9%, p < 0.05) in the validation and test sets. The AUCs of the XGBoost-based US radiomics model for discriminating carcinomas from benign GB lesions were higher than the conventional US model (0.904-0.979 vs. 0.706-0.766, p < 0.05). The XGBoost-US radiomics model performed better than the CEUS model in discriminating GB carcinomas (AUC: 0.995 vs. 0.902, p = 0.011). CONCLUSIONS: The proposed ML-based US radiomics models possess the potential capacity for risk stratification of GB masses and may reduce the unnecessary cholecystectomy rate and use of CEUS. CLINICAL RELEVANCE STATEMENT: The machine learning-based ultrasound radiomics models have potential for risk stratification of gallbladder masses and may potentially reduce unnecessary cholecystectomies. KEY POINTS: • The XGBoost-based US radiomics models are useful for the risk stratification of GB masses. • The XGBoost-based US radiomics model is superior to the conventional US model for discriminating neoplastic from non-neoplastic GB lesions and may potentially decrease unnecessary cholecystectomy rate for lesions sized over 10 mm in comparison with the current consensus guideline. • The XGBoost-based US radiomics model could overmatch CEUS model in discriminating GB carcinomas from benign GB lesions.

Validating HONO as an Intermediate Tracer of the External Cycling of Reactive Nitrogen in the Background Atmosphere.

In the urban atmosphere, nitrogen oxide (NOx═NO + NO2)-related reactions dominate the formation of nitrous acid (HONO). Here, we validated an external cycling route of HONO and NOx, i.e., formation of HONO resulting from precursors other than NOx, in the background atmosphere. A chemical budget closure experiment of HONO and NOx was conducted at a background site on the Tibetan Plateau and provided direct evidence of the external cycling. An external daytime HONO source of 100 pptv h-1 was determined. Both soil emissions and photolysis of nitrate on ambient surfaces constituted likely candidate mechanisms characterizing this external source. The external source dominated the chemical production of NOx with HONO as an intermediate tracer. The OH production was doubled as a result of the external cycling. A high HONO/NOx ratio (0.31 ± 0.06) during the daytime was deduced as a sufficient condition for the external cycling. Literature review suggested the prevalence of high HONO/NOx ratios in various background environments, e.g., polar regions, pristine mountains, and forests. Our analysis validates the prevalence of external cycling in general background atmosphere and highlights the promotional role of external cycling regarding the atmospheric oxidative capacity.

A hybrid type Ia supernova with an early flash triggered by helium-shell detonation.

Type Ia supernovae arise from the thermonuclear explosion of white-dwarf stars that have cores of carbon and oxygen. The uniformity of their light curves makes these supernovae powerful cosmological distance indicators, but there have long been debates about exactly how their explosion is triggered and what kind of companion stars are involved. For example, the recent detection of the early ultraviolet pulse of a peculiar, subluminous type Ia supernova has been claimed as evidence for an interaction between a red-giant or a main-sequence companion and ejecta from a white-dwarf explosion. Here we report observations of a prominent but red optical flash that appears about half a day after the explosion of a type Ia supernova. This supernova shows hybrid features of different supernova subclasses, namely a light curve that is typical of normal-brightness supernovae, but with strong titanium absorption, which is commonly seen in the spectra of subluminous ones. We argue that this early flash does not occur through previously suggested mechanisms such as the companion-ejecta interaction. Instead, our simulations show that it could occur through detonation of a thin helium shell either on a near-Chandrasekhar-mass white dwarf, or on a sub-Chandrasekhar-mass white dwarf merging with a less-massive white dwarf. Our finding provides evidence that one branch of previously proposed explosion models-the helium-ignition branch-does exist in nature, and that such a model may account for the explosions of white dwarfs in a mass range wider than previously supposed.

The Value of Ultra-High-Frequency Ultrasound for the Differentiation between Superficial Basal Cell Carcinoma and Bowen's Disease.

BACKGROUND: The similar visual appearance of superficial basal cell carcinoma (sBCC) and Bowen's disease (BD) may cause confusion for diagnosis. OBJECTIVE: The aim of the study was to investigate the value of ultra-high-frequency ultrasound (uHFUS) in differentiating sBCC from BD. MATERIALS AND METHODS: This prospective study included a pilot cohort of 110 patients (73 BDs and 37 sBCCs) from November 2016 to October 2020 and a validation cohort of 42 patients (30 BDs and 12 sBCCs) from July 2021 to December 2021. Clinical and uHFUS features of pathologically confirmed sBCC and BD were assessed. A predictive model was developed based on the uHFUS features of the pilot cohort. Subsequently, the model was validated and compared with clinical diagnosis in the validation cohort. RESULTS: uHFUS features with significant differences between sBCC and BD included lesion surface, skin layer involvement, hyperkeratosis, and hyperechoic spots (all p < 0.05). A prediction model based on the above features was established to identify sBCC and BD in the pilot and validation cohorts with areas under the curve (AUC) of 0.908 and 0.923, sensitivity of 82.3% and 83.3%, specificity of 91.9% and 91.7%, and accuracy of 85.5% and 85.7%, respectively, which were significantly higher than those obtained by clinical diagnosis based on photographic pictures of lesions, with the AUC of 0.692, sensitivity of 63.3%, specificity of 75.3%, and accuracy of 66.7% (all p < 0.05). CONCLUSION: uHFUS provides detailed internal features of sBCC and BD, which facilitates the differentiation between sBCC and BD, and its diagnostic performance is superior to clinical diagnosis.

Diagnostic value of high-frequency ultrasound (HFUS) in evaluation of subcutaneous lesions.

BACKGROUND: It is unknown whether high-frequency ultrasound (HFUS) can evaluate invisible subcutaneous lesions. We aimed to investigate the diagnostic value of HFUS in invisible subcutaneous lesions. METHOD: Patients with invisible subcutaneous lesions were prospectively recruited from two centres. Before undergoing biopsy or surgery, each lesion was independently evaluated by two clinicians. One provides a clinical diagnosis by only clinical examination and the other provides an integrated diagnosis by combining clinical examination and HFUS information. Diagnoses were classified as correct, wrong, and indeterminate. A total of 391 lesions from 355 patients were enrolled, including 225 epidermoid cysts, 77 lipomas, 25 pilomatrixomas, 21 haemangiomas, 19 dermatofibromas, 11 dermatofibrosarcoma protuberans (DFSP), 7 neurofibromas, and 6 leiomyomas. Using pathological results as the gold standard, diagnostic performance was compared. RESULTS: The number of correct diagnoses increased from 185 (47.3%) by clinical examination alone to 316 (80.8%) after the addition of HFUS (P < 0.05). Meanwhile, the indeterminate diagnosis rate decreased from 143 (36.6%) to 10 (2.6%). Using HFUS, the accuracy improved significantly for epidermoid cysts (59.6% vs. 86.7%), lipomas (50.6% vs. 94.8%), pilomatrixomas (0% vs. 48.0%), haemangiomas (23.8% vs. 57.1%), and DFSPs (0% vs. 81.8%) (all p < 0.05). However, HFUS did not significantly improve the diagnostic accuracy of dermatofibromas (15.8% vs. 21.1%, p > 0.999), neurofibromas (42.9% vs. 71.4%, p = 0.625), or leiomyomas (16.7% vs. 100%, p = 0.063). CONCLUSION: Combining HFUS and clinical examination can generally improve the diagnostic accuracy and decrease the indeterminacy of invisible subcutaneous lesions, especially epidermoid cysts, lipomas, pilomatrixomas, haemangiomas, and DFSPs. However, for some rare lesions, HFUS cannot provide useful information.

The Value of Ultrasound for Differentiating Trichilemmal Cysts From Epidermoid Cysts.

OBJECTIVES: This study was aimed to evaluate the diagnostic performance of ultrasound (US) in differentiating trichilemmal cysts (TCs) from epidermoid cysts (ECs). METHODS: Based on clinical and ultrasound features, a prediction model was established and validated. 164 cysts in the pilot cohort and another 69 in the validation cohort diagnosed with TCs or ECs histopathologically were evaluated. The same radiologist performed all ultrasound examinations. RESULTS: For clinic features, TCs tended to occur in females compared with ECs (66.7 vs 28.5%; P < .001). In addition, TCs were prone to occur in the hairy area compared with ECs (77.8 vs 13.1%; P < .001). For ultrasound features, the internal hyperechogenicity and cystic change were more likely to appear in TCs in comparison with ECs (92.6 vs 25.5%; P < .001; 70.4 vs 23.4%; P < .001, respectively). Upon the features mentioned above, a prediction model was established with the areas under the receiver operating characteristic curves of 0.936 and 0.864 in the pilot and validation cohorts, respectively. CONCLUSIONS: US is promising for differentiating TCs from ECs and is valuable for their clinical management.

High-frequency ultrasound for differentiation between high-risk basal cell carcinoma and cutaneous squamous cell carcinoma.

BACKGROUND: The similar visual appearance of high-risk basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC) may cause confusion for diagnosis. High-frequency ultrasound (HFUS) may provide additional intralesional information and thus help to distinguish them. METHOD: In this retrospective study, we analyzed the clinical characteristics, HFUS grayscale, and color Doppler flow imaging (CDFI) features of pathologically confirmed high-risk BCC and cSCC lesions (n = 65 vs n = 68). Subsequently, discrimination models based on the significant HFUS features were established. RESULTS: Between high-risk BCC and cSCC lesions, the HFUS grayscale features of the lesion size (10.0 mm vs 17.4 mm), thickness (3.1 mm vs 5.9 mm), internal hyperechoic spots (80.0% vs 23.5%), and posterior acoustic shadowing (16.9% vs 66.2%) were statistically different (all p < 0.001). As for the CDFI features, high-risk BCC lesions mainly appeared as pattern II (47.7%), while cSCC lesions mainly appeared as pattern III (66.2%). Based on the above five features, an optimal discrimination model was established with a sensitivity of 91.2%, a specificity of 87.7%, and an accuracy of 89.5%. CONCLUSION: HFUS features, including size, thickness, internal hyperechoic spots, posterior acoustic shadowing, and Doppler vascularity pattern, are useful for differential diagnosis between high-risk BCC and cSCC.

High-Frequency Ultrasound for Evaluation of the Pathological Invasion Level of Extramammary Paget Disease.

OBJECTIVES: Pathological invasion level of extramammary Paget disease (EMPD) is strongly related with its risk staging, treatment, and prognosis. However, the current evaluation before treatments fails to evaluate pathological invasion level of EMPD. High-frequency ultrasound (HFUS) may play a key role to solve this problem. The purpose was to explore the performance of HFUS in the evaluation of pathological invasion level of EMPD. METHODS: Sixty pathologically proven EMPD patients were retrospectively enrolled and divided into 2 groups as follows: in situ in the epidermis (IE) (n = 42) and invasion into the dermis or subcutaneous (ID) (n = 18) groups. Clinical and HFUS features were compared between the 2 groups. RESULTS: Between the 2 groups, HFUS features (lesion shape, internal echogenicity and echotexture, surface shape, epidermal hyperechoic layer on the surface, the "pseudopod sign", and color Doppler ultrasound features) and clinical features were comparable (all P >.05). Tumor growth pattern significantly differed between the 2 groups (P <.05). Infiltration depth was significantly deeper for the ID group than the IE group (P <.05). With a cutoff value of 1.55 mm for infiltration depth, the area under the receiver operating characteristic curve was 0.833. CONCLUSIONS: HFUS features of tumor growth pattern and infiltration depth may contribute to the assessment of invasion level of EMPD.

Cobalt-Catalyzed Diastereo- and Enantioselective Reductive Allyl Additions to Aldehydes with Allylic Alcohol Derivatives via Allyl Radical Intermediates.

Catalytic generation of ambiphilic π-allyl-metal complexes and their utility in enantioselective transformations constitutes a powerful approach for introduction of allyl groups to a molecule. Herein an unprecedented cobalt-catalyzed highly site-, diastereo-, and enantioselective protocol for stereoselective formation of nucleophilic allyl-Co(II) complexes followed by addition to aldehydes is presented. The reaction features diastereo- and enantioconvergent conversion of easily accessible allylic alcohol derivatives to diversified enantioenriched homoallylic alcohols with a remarkably broad scope of allyl groups that can be introduced. Mechanistic studies indicated that allyl radical intermediates were involved in this process. These new discoveries establish a new strategy for development of enantioselective transformations through capture of radicals by chiral Co complexes, pushing forward the frontier of Co complexes for enantioselective catalysis.

High-frequency ultrasound in the diagnosis of the spectrum of cutaneous squamous cell carcinoma: Noninvasively distinguishing actinic keratosis, Bowen's Disease, and invasive squamous cell carcinoma.

OBJECTIVE: To evaluate high-frequency ultrasound (HFUS) features for diagnosing cutaneous squamous cell carcinoma (cSCC) as a spectrum of progressively advanced malignancies, including precursor actinic keratosis (AK), Bowen's disease (BD), and invasive squamous cell carcinoma (iSCC). METHOD: In this retrospective study, 160 skin lesions diagnosed histopathologically (54 AK, 54 BD, and 52 iSCC) in 160 patients were included. The HFUS features of AK, BD, and iSCC were analyzed. The obtained data were evaluated using univariate and forward multivariate logistic regression analyses. RESULTS: The most significant HFUS features in AK were regular surface (odds ratio [OR], 8.42) and irregular basal border (OR, 6.36). The most significant HFUS features in BD were crumpled surface (OR, 19.62) and layer involvement confined to the epidermis (OR, 3.96). The most significant HFUS features in iSCC were concave surface (OR, 27.06), stratum corneum (SC) detachment (OR, 14.41), irregular basal border (OR, 4.01), and convex surface (OR, 3.73). The characteristics of surface features, basal border, and layer involvement could be valuable HFUS clues in the discrimination of AK, BD, and iSCC. CONCLUSION: High-frequency ultrasound is valuable for the differentiation of AK, BD, and iSCC, which may allow dynamic and noninvasive monitoring in the spectrum of cSCC.

Circular RNA circ-RAD23B promotes cell growth and invasion by miR-593-3p/CCND2 and miR-653-5p/TIAM1 pathways in non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is an aggressive malignancy with poor clinical outcomes. Accumulating evidence indicated that dysregulation of circular RNAs (circRNAs) plays a key role in multiple solid tumors. In this study, circ-RAD23B was explored. The expression of circ-RAD23B in NSCLC was detected by RT-qPCR. The clinical value of circ-RAD23B was analyzed by Fisher's exact test and Kaplan-Meier curves. Gain and loss of function experiments were carried out to elucidate the biological functions of circ-RAD23B in NSCLC cell lines. Dual luciferase reporter assay and rescue experiments were used to reveal the mechanism of circ-RAD23B. The findings demonstrated that circ-RAD23B, identified to be amplified and overexpressed in NSCLC, was associated with lymph node invasion, lower differentiation grade and shorter overall survival (OS). Furthermore, circ-RAD23B functions as an oncogene in NSCLC cells. Mechanistically, circ-RAD23B could sponge miR-593-3p and miR-653-5p and thus elevate CCND2 and TIAM1 expression, respectively. Rescue assays proved that circ-RAD23B promotes cell growth via miR-593-3p/CCND2 axis and facilitates cell invasion by miR-653-5p/TIAM1 pathway. Taken together, we propose circ-RAD23B as a promising biomarker and therapeutic target for NSCLC.

Austenite Growth Behavior and Prediction Modeling of Ti Microalloyed Steel.

Previous studies on the austenite grain growth were mostly based on a fixed temperature, and the relationship between the austenite grain and austenitizing parameters was fitted according to the results. However, there is a lack of quantitative research on the austenite grain growth during the heating process. In the present work, based on the diffusion principle of the controlled Ti microalloying element, the diffusion process of carbonitrides containing Ti during the heating process was analyzed. Combined with the precipitation model and the austenite growth model, the prediction model of austenite grain growth of Ti microalloyed steel during different heat treatment processes was established. The austenite grain size versus the temperature at four different heating rates of 0.5, 1, 10, 100 °C/s was calculated. The grain growth behavior of austenite during the heating process of Ti microalloyed steel was studied by optical microscope, scanning electron microscope and transmission electron microscope. The experimental data of the austenite grain size was in good agreement with the calculation by the proposed model, which provides a new idea for the prediction of austenite grain size in non-equilibrium state during the heating process. In addition, for Ti-containing microalloyed steels, the austenite grain size increased with the increasing heating temperature, while it changed little by further prolonging isothermal time after certain heating time, which was related to the equilibrium degree of the precipitation and the dissolution of Ti element. The austenite grain coarsening temperature of the tested Ti microalloyed steel was estimated within 1100~1200 °C.

Risk stratification model for incidentally detected gallbladder polyps: A multicentre study.

PURPOSE: We aimed to develop a 4-level risk stratification model using a scoring system based on conventional ultrasound to improve the diagnosis of gallbladder polyp. METHOD: Patients with histopathologically confirmed gallbladder polyps were consecutively recruited from three medical centres. Conventional ultrasound findings and clinical characteristics were acquired prior to cholecystectomy. Risk factors for neoplastic and malignant polyps were used to build a risk stratification system via interobserver agreement and multivariate logistic regression analysis. The model was retrospectively trained using 264 pre-surgical samples and prospectively validated using 106 pre-surgical samples. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC) and malignant polyp rate. RESULTS: In total, 370 patients (mean age, 51.68 ± 14.41 years, 156 men) were enrolled in this study. Size (≥12 mm), shape (oblate or round), single, vascularity, gallbladder stone or sludge were considered risk factors for neoplastic polyps. Size (≥14 mm), shape (oblate), single, disrupted gallbladder wall, and gallbladder stone or sludge were risk factors for malignant polyps (all p < 0.05). In the scoring system, the sensitivity, specificity, and AUC of score ≥ 9 in diagnosing neoplastic polyps were 0.766, 0.788, and 0.876 respectively; and the sensitivity, specificity, and AUC of score ≥ 15 in diagnosing malignant polyps were 0.844, 0.926, and 0.949 respectively. In our model, the malignancy rates at the four levels were 0 % (0/24), 1.28 % (2/156), 9.26 % (5/54), and 70.37 % (38/54), respectively. CONCLUSIONS: The 4-level risk stratification model based on conventional ultrasound imaging showed excellent performance in classifying gallbladder polyps.

Quantitative US fat fraction for noninvasive assessment of hepatic steatosis in suspected metabolic-associated fatty liver disease.

OBJECTIVES: To evaluate the agreement between quantitative ultrasound system fat fraction (USFF) and proton magnetic resonance spectroscopy (1H-MRS) and the diagnostic value of USFF in assessing metabolic-associated fatty liver disease (MAFLD). METHODS: The participants with or suspected of MAFLD were prospectively recruited and underwent 1H-MRS, USFF, and controlled attenuation parameter (CAP) measurements. The correlation between USFF and 1H-MRS was assessed using Pearson correlation coefficients. The USFF diagnostic performance for different grades of steatosis was evaluated using receiver operating characteristic curve analysis (ROC) and was compared with CAP, visual hepatic steatosis grade (VHSG). RESULTS: A total of 113 participants (mean age 44.79 years ± 13.56 (SD); 71 males) were enrolled, of whom 98 (86.73%) had hepatic steatosis (1H-MRS ≥ 5.56%). USFF showed a good correlation (Pearson r = 0.76) with 1H-MRS and showed a linear relationship, which was superior to the correlation between CAP and 1H-MRS (Pearson r = 0.61). The USFF provided high diagnostic performance for different grades of hepatic steatosis, with ROC from 0.84 to 0.98, and the diagnostic performance was better than that of the CAP and the VHSG. The cut-off values of the USFF were different for various grades of steatosis, and the cut-off values for S1, S2, and S3 were 12.01%, 19.98%, and 22.22%, respectively. CONCLUSIONS: There was a good correlation between USFF and 1H-MRS. Meanwhile, USFF had good diagnostic performance for hepatic steatosis and was superior to CAP and VHSG. USFF represents a superior method for noninvasive quantitative assessment of MAFLD. CRITICAL RELEVANCE STATEMENT: Quantitative ultrasound system fat fraction (USFF) accurately assesses liver fat content and has a good correlation with magnetic resonance spectroscopy (1H-MRS) for the assessment of metabolic-associated fatty liver disease (MAFLD), as well as for providing an accurate quantitative assessment of hepatic steatosis. KEY POINTS: Current diagnostic and monitoring modalities for metabolic-associated fatty liver disease have limitations. USFF correlated well with 1H-MRS and was superior to the CAP. USFF has good diagnostic performance for steatosis, superior to CAP and VHSG.