Recoverability of zebrafish from decabromodiphenyl ether exposure: The persisted interference with extracellular matrix production and collagen synthesis and the enhancement of arrhythmias.

As a widely used brominated flame retardant, the widespread presence of decabromodiphenyl ether (BDE-209) in the natural environment and the toxicity risks it poses are well established, but the recoverability of BDE-209-induced individual injuries remains unknown. Therefore, a 7-day depuration experiment following a 4-day exposure of zebrafish to BDE-209 was conducted to confirm the recoverability and its mode of action. Oxidative stress after depuration was significantly reduced compared with BDE-209 exposure as indicated by the decreased expression level of oxidative stress-related genes and the reduced MDA, Gpx, and GST in zebrafish, indicating a gradual recovery of antioxidant activity. However, BDE-209 inhibition of extracellular matrix (ECM) proteins worsened after depuration. Mechanistically, BDE-209 mediated ECM production and secretion by down-regulating integrin expression. Furthermore, BDE-209 inhibition of collagen synthesis worsened after depuration. Biochemical assays and histopathological observations revealed a same result in zebrafish. Mechanistically, lysine hydroxylation is inhibited thereby affecting collagen synthesis. Interestingly, zebrafish showed arrhythmia after depuration compared to BDE-209 exposure, and abnormal changes in ATPase levels indicated that disturbances in Ca2+ homeostasis contributed to arrhythmia. Collectively, BDE-209-induced interference with ECM production and collagen synthesis persisted after depuration, which will provide new insights for understanding the recovery patterns of individuals under BDE-209 stress.

Salinirarus marinus gen. nov., sp. nov., Haloplanus salilacus sp. nov., Haloplanus pelagicus sp. nov., Haloplanus halophilus sp. nov., Haloplanus halobius sp. nov., halophilic archaea isolated from commercial coarse salts with potential as starter cultures for salt-fermented foods.

Five halophilic archaeal strains, XH8T, CK5-1T, GDY1T, HW8-1T, and XH21T, were isolated from commercial coarse salt produced in different regions of China. Their 16S rRNA and rpoB' gene sequences indicated that four of the strains (CK5-1T, GDY1T, HW8-1T, and XH21T) represent distinct species within the genus Haloplanus (family Haloferacaceae), while strain XH8T represents a novel genus within the same family. These assignments were supported by phylogenetic and phylogenomic analyses, which showed that strains CK5-1T, GDY1T, HW8-1T, and XH21T cluster with the current species of the genus Haloplanus, while strain XH8T forms a separate branch from the genus Haloplanus. The digital DNA-DNA hybridization and average amino acid identity (AAI) values among these four strains and the current members of the genus Haloplanus were 23.1-35.2% and 75.9-83.8%, respectively; and those values between strain XH8T and other genera in the family Haloferacaceae were 18.8-33.6% and 59.8-66.6%, respectively, much lower than the threshold values for species demarcation. Strain XH8T may represent a novel genus of the family Haloferacaceae according to the cut-off value of AAI (≤72.1%) proposed to differentiate genera within the family Haloferacaceae. These five strains could be distinguished from the related species according to differential phenotypic characteristics. Based on these results, it is proposed that strain XH8T represents a novel genus within the family Haloferacaceae, and strains CK5-1T, GDY1T, HW8-1T, and XH21T represent four novel species of the genus Haloplanus, respectively. Additionally, these five strains possess genes encoding enzymes critical for the fermentation process in salt-fermented foods, indicating their potential as starter cultures for these applications.

Aged bone marrow macrophages drive systemic aging and age-related dysfunction via extracellular vesicle-mediated induction of paracrine senescence.

The accumulation and systemic propagation of senescent cells contributes to physiological aging and age-related pathology. However, which cell types are most susceptible to the aged milieu and could be responsible for the propagation of senescence has remained unclear. Here we found that physiologically aged bone marrow monocytes/macrophages (BMMs) propagate senescence to multiple tissues, through extracellular vesicles (EVs), and drive age-associated dysfunction in mice. We identified peroxisome proliferator-activated receptor α (PPARα) as a target of microRNAs within aged BMM-EVs that regulates downstream effects on senescence and age-related dysfunction. Demonstrating therapeutic potential, we report that treatment with the PPARα agonist fenofibrate effectively restores tissue homeostasis in aged mice. Suggesting conservation to humans, in a cohort study of 7,986 participants, we found that fenofibrate use is associated with a reduced risk of age-related chronic disease and higher life expectancy. Together, our findings establish that BMMs can propagate senescence to distant tissues and cause age-related dysfunction, and they provide supportive evidence for fenofibrate to extend healthy lifespan.

Visible-Light-Promoted Reduction of Nitroarenes with Formate Salts as Reductants.

A visible-light-promoted reduction of nitrobenzenes using formate salts as the reductant was developed. A wide range of nitrobenzenes can be converted into aniline products in a transition metal free fashion. Mechanistic studies revealed that radical species (carbon dioxide radical anion and thiol radical) are key intermediates for the transformation. We anticipate that this method will provide a valuable and green strategy for the reduction of nitrobenzenes.

Integrative radiopathomics model for predicting progression-free survival in patients with nonmetastatic nasopharyngeal carcinoma.

PURPOSE: To construct an integrative radiopathomics model for predicting progression-free survival (PFS) in nonmetastatic nasopharyngeal carcinoma (NPC) patients. METHODS: 357 NPC patients who underwent pretreatment MRI and pathological whole-slide imaging (WSI) were included in this study and randomly divided into two groups: a training set (n = 250) and validation set (n = 107). Radiomic features extracted from MRI were selected using the minimum redundancy maximum relevance and least absolute shrinkage and selection operator methods. The pathomics signature based on WSI was constructed using a deep learning architecture, the Swin Transformer. The radiopathomics model was constructed by incorporating three feature sets: the radiomics signature, pathomics signature, and independent clinical factors. The prognostic efficacy of the model was assessed using the concordance index (C-index). Kaplan-Meier curves for the stratified risk groups were tested by the log-rank test. RESULTS: The radiopathomics model exhibited superior predictive performance with C-indexes of 0.791 (95% confidence interval [CI]: 0.724-0.871) in the training set and 0.785 (95% CI: 0.716-0.875) in the validation set compared to any single-modality model (radiomics: 0.619, 95% CI: 0.553-0.706; pathomics: 0.732, 95% CI: 0.662-0.802; clinical model: 0.655, 95% CI: 0.581-0.728) (all, P < 0.05). The radiopathomics model effectively stratified patients into high- and low-risk groups in both the training and validation sets (P < 0.001). CONCLUSION: The developed radiopathomics model demonstrated its reliability in predicting PFS for NPC patients. It effectively stratified individual patients into distinct risk groups, providing valuable insights for prognostic assessment.

The role and mechanism of AMPK in pulmonary hypertension.

Pulmonary hypertension (PH) is a chronic progressive disease with high mortality. There has been more and more research focusing on the role of AMPK in PH. AMPK consists of three subunits-α, ß, and γ. The crosstalk among these subunits ultimately leads to a delicate balance to affect PH, which results in conflicting conclusions about the role of AMPK in PH. It is still unclear how these subunits interfere with each other and achieve balance to improve or deteriorate PH. Several signaling pathways are related to AMPK in the treatment of PH, including AMPK/eNOS/NO pathway, Nox4/mTORC2/AMPK pathway, AMPK/BMP/Smad pathway, and SIRT3-AMPK pathway. Among these pathways, the role and mechanism of AMPK/eNOS/NO and Nox4/mTORC2/AMPK pathways are clearer than others, while the SIRT3-AMPK pathway remains still unclear in the treatment of PH. There are drugs targeting AMPK to improve PH, such as metformin (MET), MET combination, and rhodiola extract. In addition, several novel factors target AMPK for improving PH, such as ADAMTS8, TUFM, and Salt-inducible kinases. However, more researches are needed to explore the specific AMPK signaling pathways involved in these novel factors in the future. In conclusion, AMPK plays an important role in PH.

Disruption of glucose homeostasis by bacterial infection orchestrates host innate immunity through NAD+/NADH balance.

Metabolic reprogramming is crucial for activating innate immunity in macrophages, and the accumulation of immunometabolites is essential for effective defense against infection. The NAD+/NADH (ratio of nicotinamide adenine dinucleotide and its reduced counterpart) redox couple serves as a critical node that integrates metabolic pathways and signaling events, but how this metabolite couple engages macrophage activation remains unclear. Here, we show that the NAD+/NADH ratio serves as a molecular signal that regulates proinflammatory responses and type I interferon (IFN) responses divergently. Salmonella Typhimurium infection leads to a decreased NAD+/NADH ratio by inducing the accumulation of NADH. Further investigation shows that an increased NAD+/NADH ratio correlates with attenuated proinflammatory responses and enhanced type I IFN responses. Conversely, a decreased NAD+/NADH ratio is linked to intensified proinflammatory responses and restrained type I IFN responses. These results show that the NAD+/NADH ratio is an essential cell-intrinsic factor that orchestrates innate immunity, which enhances our understanding of how metabolites fine-tune innate immunity.

A recoverable hydrophilic deep eutectic solvent for efficient extraction of polyphenolic compounds from raspberry root.

Green deep eutectic solvents (DESs) are widely used to extract bioactive components from plant biomass; however, hydrophilic DES and bioactive component isolation methods have not been developed. In this study, we synthesized hydrophilic DES (CL-CA-DES) using citric acid and choline chloride. We combined this with environmentally friendly anion- and cation-exchange resin column chromatographic isolation methods. This approach extracted and isolated four polyphenolic compounds (catechins, epicatechins, procyanidin B1, and procyanidin B2) from raspberry root and efficiently recovered the hydrophilic DES. CL-CA-DES extracted significantly higher contents of catechin and procyanidin B2 from raspberry root compared to other solvents. It also extracted substantially higher contents of epicatechin compared to butyl alcohol, 70% ethanol, and water, but there was no significant difference when compared with acetone and ethyl acetate. Additionally, CL-CA-DES extracted significantly higher contents of procyanidin B1 compared to butyl alcohol, water, and ethyl acetate, with no significant difference when compared with 70% ethanol and acetone. The isolation efficiency of the bioactive components in the raspberry root extract by anion- and cation-exchange resin column chromatography was higher than that of the organic solvent extraction and precipitation generation methods, and the method was effective in recovering CL-CA-DES with a recovery rate higher than 60%. In conclusion, this study developed a new method for the efficient recovery of hydrophilic CL-CA-DES, which can be used for isolating polyphenolic compounds from raspberry root.

A phase II study of post-remission therapy with pembrolizumab in older patients with acute myeloid leukemia.

Not available.

Genome-Wide Identification and Characterization of Maize Long-Chain Acyl-CoA Synthetases and Their Expression Profiles in Different Tissues and in Response to Multiple Abiotic Stresses.

Long-chain acyl-CoA synthetases (LACSs) are essential enzymes that activate free fatty acids to fatty acyl-CoA thioesters, playing key roles in fatty acid (FA) catabolism, lipid synthesis and storage, epidermal wax synthesis, and stress tolerance. Despite their importance, comprehensive information about LACS genes in maize, a primary food crop, remains scarce. In the present work, eleven maize LACS genes were identified and mapped across five chromosomes. Three pairs of segmentally duplicated genes were detected in the maize LACS gene family, which underwent significant purifying selection (Ka/Ks < 1). Subsequently, phylogenetic analysis indicated that ZmLACS genes were divided into four subclasses, as supported by highly conserved motifs and gene structures. On the basis of the PlantCARE database, analysis of the ZmLACS promoter regions revealed various cis-regulatory elements related to tissue-specific expression, hormonal regulation, and abiotic stress response. RT-qPCR analysis showed that ZmLACS genes exhibit tissue-specific expression patterns and respond to diverse abiotic stresses including drought and salt, as well as phytohormone abscisic acid. Furthermore, using the STRING database, several proteins involved in fatty acid and complex lipid synthesis were identified to be the potential interaction partners of ZmLACS proteins, which was also confirmed by the yeast two-hybrid (Y2H) assay, enhancing our understanding of wax biosynthesis and regulatory mechanisms in response to abiotic stresses in maize. These findings provide a comprehensive understanding of ZmLACS genes and offer a theoretical foundation for future research on the biological functions of LACS genes in maize environmental adaptability.

The High Resistance Loop (H-Loop) Technique for Arthroscopic Repair of Subscapularis.

The subscapularis tendon is more challenging and riskier to repair than the posterior upper rotator cuff. The knotless anchor suture in subscapularis repair simplified the repair process and had an excellent postoperative effect. We describe a new knotless anchor stitching method, the H-Loop technique. The simplicity and efficiency of the technique make it particularly suitable for small subscapular tendon tears.

Imaging-based surrogate classification for risk stratification of hepatocellular carcinoma with microvascular invasion to adjuvant hepatic arterial infusion chemotherapy: a multicenter retrospective study.

BACKGROUND: Patients with microvascular invasion (MVI)-positive hepatocellular carcinoma (HCC) have shown promising results with adjuvant hepatic arterial infusion chemotherapy (HAIC) with FOLFOX after curative resection. We aim to develop an imaging-derived biomarker to depict MVI-positive HCC patients more precisely and promote individualized treatment strategies of adjuvant HAIC. MATERIALS AND METHODS: Patients with MVI-positive HCC were identified from five academic centers and utilized for model development (n=470). Validation cohorts were pooled from a previously reported prospective clinical study conducted (control cohort (n=145), adjuvant HAIC cohort (n=143)) (NCT03192618). The primary endpoint was recurrence-free survival (RFS). Imaging features were thoroughly reviewed, and multivariable logistic regression analysis was employed for model development. Transcriptomic sequencing was conducted to identify the associated biological processes. RESULTS: Arterial phase peritumoral enhancement, boundary of the tumor enhancement, tumor necrosis stratification, and boundary of the necrotic area were selected and incorporated into the nomogram for RFS. The imaging-based model successfully stratified patients into two distinct prognostic subgroups in both the training, control, and adjuvant HAIC cohorts (median RFS, 6.00 vs. 66.00 mo, 4.86 vs. 24.30 mo, 11.46 vs. 39.40 mo, all P<0.01). Furthermore, no significant statistical difference was observed between patients at high-risk of adjuvant HAIC and those in the control group (P=0.61). The area under the receiver operating characteristic curve at two years was found to be 0.83, 0.84, and 0.73 for the training, control, and adjuvant HAIC cohorts respectively. Transcriptomic sequencing analyses revealed associations between the radiological features and immune-regulating signal transduction pathways. CONCLUSION: The utilization of this imaging-based model could help to better characterize MVI-positive HCC patients and facilitate the precise subtyping of patients who genuinely benefit from adjuvant HAIC treatment.

Postoperative outcomes of minimally invasive versus conventional nipple-sparing mastectomy with prosthesis breast reconstruction in breast cancer: a meta-analysis.

Breast cancer is the most common malignant tumor worldwide, and mastectomy remains the primary strategy for treating early stage breast cancer. However, the complication rates, surgical variables, and oncologic safety of minimally invasive nipple-sparing mastectomy (MINSM) have not been fully addressed. We systematically searched PubMed, Web of Science, Embase, and the Cochrane Library for randomized-controlled trials (RCTs) and non-RCTs that compared MINSM with conventional nipple-sparing mastectomy (CNSM), both followed by Prosthesis Breast Reconstruction (PBR). The main outcomes observed included overall complications, (Grade III) complications, skin and nipple necrosis, wound dehiscence, infection, seroma, hematoma, implant loss, and oncologic safety (positive margins and recurrence). Secondary outcomes included operation time, blood loss, hospital stay, cost-effectiveness, and patient satisfaction. Binary and continuous variables were compared using odds ratios (OR) and mean differences (MD) with 95% confidence intervals (CI). A total of 10 studies involving 2,166 patients were included. There were no statistically significant differences between MINSM and CNSM in terms of skin necrosis, wound dehiscence, infection, seroma, hematoma, implant loss, or oncologic safety. However, MINSM significantly reduced overall complications (OR = 0. 74, 95% CI [0. 58, 0. 94], p = 0. 01) and (Grade III) complications (OR = 0. 47, 95% CI [0. 31, 0. 71], p = 0. 0003). Nipple necrosis events were also significantly reduced in the MINSM group (OR = 0. 49, 95% CI [0. 30, 0. 80], p = 0. 005). Patient satisfaction improved notably in the MINSM group. Additionally, compared with the CNSM group, the MINSM group had longer operating times (MD = 46. 88, 95% CI [19. 55, 74. 21], p = 0. 0008) and hospital stays (MD = 1. 39, 95% CI [0. 65, 2. 12], p < 0. 001), while intraoperative blood loss was significantly reduced (MD = -29. 05, 95% CI [-36. 20, -21. 90], p < 0. 001). Compared with CNSM, MINSM offers advantages in reducing complications and intraoperative blood loss, as well as improving aesthetic outcomes and patient satisfaction. Therefore, MINSM may become a viable option for breast surgery. Nevertheless, a long-term evaluation of the oncologic safety of this approach is necessary to ensure its efficacy and safety for patients.

Macrophage-derived extracellular vesicles regulate skeletal stem/progenitor Cell lineage fate and bone deterioration in obesity.

Obesity-induced chronic inflammation exacerbates multiple types of tissue/organ deterioration and stem cell dysfunction; however, the effects on skeletal tissue and the underlying mechanisms are still unclear. Here, we show that obesity triggers changes in the microRNA profile of macrophage-secreted extracellular vesicles, leading to a switch in skeletal stem/progenitor cell (SSPC) differentiation between osteoblasts and adipocytes and bone deterioration. Bone marrow macrophage (BMM)-secreted extracellular vesicles (BMM-EVs) from obese mice induced bone deterioration (decreased bone volume, bone microstructural deterioration, and increased adipocyte numbers) when administered to lean mice. Conversely, BMM-EVs from lean mice rejuvenated bone deterioration in obese recipients. We further screened the differentially expressed microRNAs in obese BMM-EVs and found that among the candidates, miR-140 (with the function of promoting adipogenesis) and miR-378a (with the function of enhancing osteogenesis) coordinately determine SSPC fate of osteogenic and adipogenic differentiation by targeting the Pparα-Abca1 axis. BMM miR-140 conditional knockout mice showed resistance to obesity-induced bone deterioration, while miR-140 overexpression in SSPCs led to low bone mass and marrow adiposity in lean mice. BMM miR-378a conditional depletion in mice led to obesity-like bone deterioration. More importantly, we used an SSPC-specific targeting aptamer to precisely deliver miR-378a-3p-overloaded BMM-EVs to SSPCs via an aptamer-engineered extracellular vesicle delivery system, and this approach rescued bone deterioration in obese mice. Thus, our study reveals the critical role of BMMs in mediating obesity-induced bone deterioration by transporting selective extracellular-vesicle microRNAs into SSPCs and controlling SSPC fate.

A hyperstable, low-salt adapted protease from halophilic archaeon with potential applications in salt-fermented foods.

Salt-tolerant proteases with remarkable stability are highly desirable biocatalysts in the salt-fermented food industry. In this study, the undigested autocleavage product of HlyA (halolysin A), a low-salt adapted halolysin from halophilic archaeon Halococcus salifodinae, was investigated. HlyA underwent autocleavage of its C-terminal extension (CTE) at temperatures over 40 °C or NaCl concentrations below 2 M to yield HlyAΔCTE. HlyAΔCTE demonstrated robust stability over a wide range of -20-60 °C, 0.5-4 M NaCl, and pH 6.0-10.0 for at least 72 h. Notably, HlyAΔCTE is the first reported halolysin with such exceptional stability. Compared with HlyA, HlyAΔCTE preferred high temperatures (50-75 °C), low salinities (0.5-2.5 M NaCl), and near-neutral (pH 6.5-8.0) conditions to achieve high activity, consistently with its production conditions. HlyAΔCTE displayed a higher Vmax value against azocasein than HlyA. During fish sauce fermentation, HlyAΔCTE significantly enhanced fish protein hydrolysis, indicating its potential as a robust biocatalyst in the salt-fermented food industry.

Genome-Wide Investigation of the CRF Gene Family in Maize and Functional Analysis of ZmCRF9 in Response to Multiple Abiotic Stresses.

The cytokinin response factors (CRFs) are pivotal players in regulating plant growth, development, and responses to diverse stresses. Despite their significance, comprehensive information on CRF genes in the primary food crop, maize, remains scarce. In this study, a genome-wide analysis of CRF genes in maize was conducted, resulting in the identification of 12 members. Subsequently, we assessed the chromosomal locations, gene duplication events, evolutionary relationships, conserved motifs, and gene structures of all ZmCRF members. Analysis of ZmCRF promoter regions indicated the presence of cis-regulatory elements associated with plant growth regulation, hormone response, and various abiotic stress responses. The expression patterns of maize CRF genes, presented in heatmaps, exhibited distinctive patterns of tissue specificity and responsiveness to multiple abiotic stresses. qRT-PCR experiments were conducted on six selected genes and confirmed the involvement of ZmCRF genes in the plant's adaptive responses to diverse environmental challenges. In addition, ZmCRF9 was demonstrated to positively regulate cold and salt tolerance. Ultimately, we explored the putative interaction partners of ZmCRF proteins. In summary, this systematic overview and deep investigation of ZmCRF9 provides a solid foundation for further exploration into how these genes contribute to the complex interplay of plant growth, development, and responses to stress.

Prediction of early neurologic deterioration in patients with perforating artery territory infarction using machine learning: a retrospective study.

Background: Early neurological deterioration (END) is a frequent complication in patients with perforating artery territory infarction (PAI), leading to poorer outcomes. Therefore, we aimed to apply machine learning (ML) algorithms to predict the occurrence of END in PAI and investigate related risk factors. Methods: This retrospective study analyzed a cohort of PAI patients, excluding those with severe stenosis of the parent artery. We included demographic characteristics, clinical features, laboratory data, and imaging variables. Recursive feature elimination with cross-validation (RFECV) was performed to identify critical features. Seven ML algorithms, namely logistic regression, random forest, adaptive boosting, gradient boosting decision tree, histogram-based gradient boosting, extreme gradient boosting, and category boosting, were developed to predict END in PAI patients using these critical features. We compared the accuracy of these models in predicting outcomes. Additionally, SHapley Additive exPlanations (SHAP) values were introduced to interpret the optimal model and assess the significance of input features. Results: The study enrolled 1,020 PAI patients with a mean age of 60.46 (range 49.11-71.81) years. Of these, 30.39% were women, and 129 (12.65%) experienced END. RFECV selected 13 critical features, including blood urea nitrogen (BUN), total cholesterol (TC), low-density-lipoprotein cholesterol (LDL-C), apolipoprotein B (apoB), atrial fibrillation, loading dual antiplatelet therapy (DAPT), single antiplatelet therapy (SAPT), argatroban, the basal ganglia, the thalamus, the posterior choroidal arteries, maximal axial infarct diameter (measured at < 15 mm), and stroke subtype. The gradient-boosting decision tree had the highest area under the curve (0.914) among the seven ML algorithms. The SHAP analysis identified apoB as the most significant variable for END. Conclusion: Our results suggest that ML algorithms, especially the gradient-boosting decision tree, are effective in predicting the occurrence of END in PAI patients.

MRI-based radiomics models predict cystic brain radionecrosis of nasopharyngeal carcinoma after intensity modulated radiotherapy.

Objective: To construct radiomics models based on MRI at different time points for the early prediction of cystic brain radionecrosis (CBRN) for nasopharyngeal carcinoma (NPC). Methods: A total of 202 injured temporal lobes from 155 NPC patients with radiotherapy-induced temporal lobe injury (RTLI) after intensity modulated radiotherapy (IMRT) were included in the study. All the injured lobes were randomly divided into the training (n = 143) and validation (n = 59) sets. Radiomics models were constructed by using features extracted from T2WI at two different time points: at the end of IMRT (post-IMRT) and the first-detected RTLI (first-RTLI). A delta-radiomics feature was defined as the percentage change in a radiomics feature from post-IMRT to first-RTLI. The radiomics nomogram was constructed by combining clinical risk factors and radiomics signatures using multivariate logistic regression analysis. Predictive performance was evaluated using area under the curve (AUC) from receiver operating characteristic analysis and decision curve analysis (DCA). Results: The post-IMRT, first-RTLI, and delta-radiomics models yielded AUC values of 0.84 (95% CI: 0.76-0.92), 0.86 (95% CI: 0.78-0.94), and 0.77 (95% CI: 0.67-0.87), respectively. The nomogram exhibited the highest AUC of 0.91 (95% CI: 0.85-0.97) and sensitivity of 0.82 compared to any single radiomics model. From the DCA, the nomogram model provided more clinical benefit than the radiomics models or clinical model. Conclusion: The radiomics nomogram model combining clinical factors and radiomics signatures based on MRI at different time points after radiotherapy showed excellent prediction potential for CBRN in patients with NPC.

Correlation between vertebral bone mineral density and multi-level virtual non-calcium imaging parameters from dual-layer spectral detector computed tomography.

Background: Virtual non-calcium (VNCa) imaging based on dual-energy computed tomography (CT) plays an increasingly important role in diagnosing spinal diseases. However, the utility of VNCa technology in the measurement of vertebral bone mineral density (BMD) is limited, especially the VNCa CT value at multiple calcium suppression levels and the slope of VNCa curve. This retrospective cross-sectional study aimed to explore the correlation between vertebral BMD and new VNCa parameters from dual-layer spectral detector CT. Methods: The dual-layer spectral detector CT and quantitative CT (QCT) data of 4 hydroxyapatite (HAP) inserts and 667 vertebrae of 234 patients (132 male and 102 female) who visited a university teaching hospital between April and May 2023 were retrospectively analyzed. The BMD values of 3 vertebrae (T12, L1, and L2) and inserts were measured using QCT, defined as QCT-BMD. The VNCa CT values and the slope λ of the VNCa attenuation curve of vertebrae and inserts were recorded. The correlations between VNCa parameters (VNCa CT value, slope λ) and QCT-BMD were analyzed. Results: For the vertebrae, the correlation coefficient ranged from -0.904 to 0.712 (all P<0.05). As the calcium suppression index (CaSI) increased, the correlation degree exhibited a decrease first and then increased, with the best correlation (r=-0.904, P<0.001) observed at the index of 25%. In contrast, the correlation coefficient for the inserts remained relatively stable (r=-0.899 to -1, all P<0.05). For the vertebrae, the values of 3 slopes λ (λ1, λ2, and λ3) derived from the VNCa attenuation curve were 6.50±1.99, 3.75±1.15, and 2.04±0.62, respectively. Regarding the inserts, the λ1, λ2, and λ3 values were 11.56 [interquartile range (IQR): 2.40-22.62], 6.68 (IQR: 1.39-13.49), and 3.63 (IQR: 0.75-7.8), respectively. For the vertebrae, all 3 correlation coefficients between 3 slopes λ and QCT-BMD were 0.956 (all P<0.05). For the inserts, the 3 correlation coefficients were 0.996, 0.998, and 1 (all P<0.05), respectively. Conclusions: A promising correlation was detected between VNCa CT parameters and QCT-BMD in vertebrae, warranting further investigation to explore the possibility of VNCa imaging to assess BMD.