Involvement of NEDD9 in the invasion and migration of gastric cancer.

Recent studies have demonstrated that neural precursor cell expressed, developmentally downregulated 9 (NEDD9) is highly expressed in various tumor tissues and cell lines. However, research on the role of NEDD9 in gastric cancer (GC) is rare, and the potential mechanism in tumor progression has not yet been explored. In this study, we investigated the role and mechanism of NEDD9 in GC. The expression of NEDD9 in GC tissues and cell lines was measured by immunohistochemistry, qRT-PCR, and Western blot, respectively. Inhibiting NEDD9 expression was carried out by siRNA transfection, and upregulating of NEDD9 was via NEDD9 overexpression plasmid. The ability of proliferation, migration, and invasion was detected by MTT assay, scratch wound assay, and transwell assay, respectively. The expression of vimentin, E-cadherin, Zeb1, and Zeb2 was measured by Western blot and qRT-PCR. We found that NEDD9 expression was dramatically increased both in GC tissues and cell lines, and the expression was significantly related to GC development. Knockdown of NEDD9 in SGC-7901 strongly inhibited its malignant capacity in vitro. Meanwhile, upregulation of NEDD9 in GES-1 increased the malignant capacity. In addition, the expression of vimentin, Zeb1, and Zeb2 was positively correlated with NEDD9, while E-cadherin was opposite. Collectively, our findings suggest that NEDD9 acts as an oncogene and promotes GC metastasis via EMT.

The association of dietary inflammatory potential with skeletal muscle strength, mass, and sarcopenia: a meta-analysis.

Aims: Evidence suggested that dietary inflammatory potential may be associated with age-related skeletal muscle decline, but the results remained controversial. To summarize the evidence for the relationships between dietary inflammatory potential and skeletal muscle strength, mass, and sarcopenia in adults we conducted this meta-analysis. Methods: Embase, Pubmed, and Web of Science were searched from inception up to 12 March 2023 for studies that evaluated the associations of dietary inflammatory potential [estimated by the Dietary inflammatory index (DII)] with skeletal muscle strength, mass, and sarcopenia. A meta-analysis was then performed to calculate the pooled regression coefficient (ß) and odds ratio (OR). The non-linear dose-response relation between DII and sarcopenia was assessed using random-effects dose-response meta-analysis. Results: This meta-analysis included 24 studies involving 56,536 participants. It was found that high DII was associated with low skeletal muscle strength [OR 1.435, 95% confidence interval (CI) 1.247-1.651, P < 0.001, I2 = 4.97%]. There was a negative association of DII with skeletal muscle strength (ß-0.031, 95% CI -0.056 to -0.006, P = 0.017, I2 = 72.69%). High DII was also associated with low skeletal muscle mass (OR 1.106, 95% CI 1.058-1.157, P < 0.001, I2 = 0%). DII had a negative relationship with skeletal muscle mass with high heterogeneity (ß-0.099, 95% CI -0.145 to -0.053, P < 0.001, I2 = 88.67%); we downgraded the inconsistency in the subgroup analysis of overweight/obese participants (ß-0.042, 95% CI -0.065 to -0.019, I2 = 12.54%). Finally, the pooled results suggested that high DII was significantly associated with sarcopenia with significant heterogeneity (OR 1.530, 95% CI 1.245-1.880, P < 0.001, I2 = 69.46%); age and BMI may contribute partially to the heterogeneity since heterogeneity was decreased in the subgroup of older age (OR 1.939, 95% CI 1.232-3.051, I2 = 0%) and the group of overweight/obesity (OR 1.853, 95% CI 1.398-2.456, I2 = 0%). There was a non-linear dose-response association between DII and sarcopenia (P = 0.012 for non-linearity). Conclusion: This meta-analysis suggested that higher dietary inflammatory potential was significantly associated with lower skeletal muscle strength, mass, and risk of sarcopenia. Future studies with consistent assessment and standardized methodology are needed for further analysis.

The association between selenium and bone health: a meta-analysis.

Aims: Previous studies have suggested that selenium as a trace element is involved in bone health, but findings related to the specific effect of selenium on bone health remain inconclusive. Thus, we performed a meta-analysis by including all the relevant studies to elucidate the association between selenium status (dietary intake or serum selenium) and bone health indicators (bone mineral density (BMD), osteoporosis (OP), or fracture). Methods: PubMed, Embase, and Cochrane Library were systematically searched to retrieve relevant articles published before 15 November 2022. Studies focusing on the correlation between selenium and BMD, OP, or fracture were included. Effect sizes included regression coefficient (ß), weighted mean difference (WMD), and odds ratio (OR). According to heterogeneity, the fixed-effect or random-effect model was used to assess the association between selenium and bone health. Results: From 748 non-duplicate publications, 19 studies were included. We found a significantly positive association between dietary selenium intake (ß = 0.04, 95% confidence interval (CI) 0.00 to 0.07, p = 0.029) as well as serum selenium (ß = 0.13, 95% CI 0.00 to 0.26, p = 0.046) and BMD. Consistently, those with higher selenium intake had a lower risk of OP (OR = 0.47, 95% CI 0.31 to 0.72, p = 0.001), and patients with OP had a significantly lower level of serum selenium than healthy controls (WMD = -2.01, 95% CI -3.91 to -0.12, p = 0.037). High dietary selenium intake was associated with a lower risk of hip fracture (OR = 0.44, 95% CI 0.37 to 0.52, p < 0.001). Conclusion: Selenium was positively associated with BMD and inversely associated with OP; dietary selenium intake was negatively associated with hip fracture. The causality and therapeutic effect of selenium on OP needs to be investigated in future studies.

Motion artifact reduction for magnetic resonance imaging with deep learning and k-space analysis.

Motion artifacts deteriorate the quality of magnetic resonance (MR) images. This study proposes a new method to detect phase-encoding (PE) lines corrupted by motion and remove motion artifacts in MR images. 67 cases containing 8710 slices of axial T2-weighted images from the IXI public dataset were split into three datasets, i.e., training (50 cases/6500 slices), validation (5/650), and test (12/1560) sets. First, motion-corrupted k-spaces and images were simulated using a pseudo-random sampling order and random motion tracks. A convolutional neural network (CNN) model was trained to filter the motion-corrupted images. Then, the k-space of the filtered image was compared with the motion-corrupted k-space line-by-line, to detect the PE lines affected by motion. Finally, the unaffected PE lines were used to reconstruct the final image using compressed sensing (CS). For the simulated images with 35%, 40%, 45%, and 50% unaffected PE lines, the mean peak signal-to-noise ratio (PSNRs) of resulting images (mean±standard deviation) were 36.129±3.678, 38.646±3.526, 40.426±3.223, and 41.510±3.167, respectively, and the mean structural similarity (SSIMs) were 0.950±0.046, 0.964±0.035, 0.975±0.025, and 0.979±0.023, respectively. For images with more than 35% PE lines unaffected by motion, images reconstructed with proposed algorithm exhibited better quality than those images reconstructed with CS using 35% under-sampled data (PSNR 37.678±3.261, SSIM 0.964±0.028). It was proved that deep learning and k-space analysis can detect the k-space PE lines affected by motion and CS can be used to reconstruct images from unaffected data, effectively alleviating the motion artifacts.

[Protective effects of dexamethasone combined with valsartan on chronic obstructive pulmonary disease in mice and its mechanism].

Objective: To investigate the possible protective effects of combined dexamethasone and valsartan against cigarette induced chronic obstructive pulmonary disease (COPD) in mice. Methods: Forty C57BL/6 mice were randomly divided into control group, COPD group, dexamethasone treated group, valsartan treated group and dexamethasone + valsartan combined treatment group, with 8 mice in each group. Mice in COPD group were exposed to cigarette for 8 weeks. On the basis of cigarette exposure, mice in dexamethasone treated group were intraperitoneally injected with dexamethasone (2 mg / kg) before cigarette exposure for 5-8 weeks. Mice in valsartan treated group were intraperitoneally injected with valsartan (30 mg/kg) before cigarette exposure for 1-8 weeks. Dexamethasone (2 mg/kg) and valsartan (30 mg/kg) were injected intraperitoneally into mice in the dexamethasone + valsartan combined treatment group. After 8 weeks, the lung tissues and bronchoalveolar lavage fluid (BALF) of mice in each group were collected. The pathological score of lung tissue was evaluated. The activities of superoxide dismutase(SOD) and matrix metalloproteinase-9 (MMP-9), and the contents of malondialdehyde (MDA), intracellular adhesion molecule-1 (ICAM-1), C-reactive protein (CRP) and nitric oxide (NO) in BALF were determined. Results: Compared with the control group, COPD mice had emphysema and alveolar congestion, the levels of MDA, ICAM-1, MMP-9, CRP and lymphocytes in BALF were increased, while the levels of SOD, macrophages and NO were decreased (all P＜0.05). Compared with COPD group, there was no significant improvement in emphysema and alveolar congestion, the levels of SOD and NO in BALF were increased, and the levels of MDA, lymphocytes and macrophages were decreased in dexamethasone or valsartan group (all P＜0.05). Compared with dexamethasone or valsartan group, the dexamethasone + valsartan combined treatment was more effective in preventing pulmonary emphysema and alveolar congestion caused by cigarette smoke. The levels of MDA, ICAM-1, MMP-9, CRP and lymphocyte in BALF were decreased, while the levels of SOD, macrophage and NO were increased (all P＜0.05). Conclusion: Compared with dexamethasone or valsartan, dexamethasone combined with valsartan has a more effective protective effect in COPD mice by inhibiting oxidative stress and inflammation.

Travel-associated outbreak of COVID-19 in a departmental store, Wenzhou, China.

INTRODUCTION: A local outbreak of coronavirus disease 2019 (COVID-19) has rapidly evolved into a global pandemic and the number of cases and deaths has increased exponentially. In this study, we report a COVID-19 outbreak that occurred in a departmental store, between January and February 2020, in Wenzhou, China and investigated the reasons for the outbreak. METHODOLOGY: An outbreak investigation was initiated after the index case was diagnosed as COVID-19. Cases (confirmed and suspected) and close contacts were defined. Their pharyngeal swabs were collected and examined with real-time polymerase chain reaction (RT-PCR) for nucleic acid. All investigations of the confirmed and suspected cases were carried out by epidemiologists and the source of infection was tracked by using big data. RESULTS: Thirty-nine COVID-19 cases and one asymptomatic individual were found in this outbreak, as determined by clinical manifestations, epidemiological investigation, and RT-PCR. Majority of COVID-19 cases occurred in a departmental store, three of whom traveled to participate in a meeting held in H city. After disease outbreak in the departmental store, intra-family transmission of COVID-19 occurred in five families. Two clusters of the COVID-19 outbreak were identified. One cluster was attributed to the family party, while another was attributed to a hotel party, which was responsible for transmission across three generations, infecting five family members. CONCLUSIONS: This was travel associated COVID-19 outbreak in a departmental store in Wenzhou, China. High infectivity of COVID-19 was observed. A departmental store, especially without recirculation of the air, was a high-risk site for the transmission of COVID-19. The use of big data and related information was very useful in epidemiological investigation of cases and contacts.

Gut dysbiosis in rheumatic diseases: A systematic review and meta-analysis of 92 observational studies.

BACKGROUND: Emerging evidence suggests that dysbiosis in gut microbiota may contribute to the occurrence or development of several rheumatic diseases. Since gut microbiota dysbiosis is potentially modifiable, it has been postulated to be a promising preventive or therapeutic target for rheumatic diseases. However, the current understanding on the potential associations between gut microbiota and rheumatic diseases is still inadequate. Therefore, we aimed to synthesise the accumulating evidence for the relation of gut microbiota to rheumatic diseases. METHODS: The PubMed, Embase and Cochrane Library were searched from inception to March 11, 2022 to include observational studies evaluating the associations between gut microbiota and rheumatic diseases. Standardised mean difference (SMD) of α-diversity indices between rheumatic diseases and controls were estimated using random-effects model. ß-diversity indices and relative abundance of gut microbes were summarised qualitatively. FINDINGS: Of the included 92 studies (11,998 participants), 68 provided data for α-diversity. Taken together as a whole, decreases in α-diversity indices were consistently found in rheumatic diseases (observed species: SMD = -0.36, [95%CI = -0.63, -0.09]; Chao1: SMD = -0.57, [95%CI = -0.88, -0.26]; Shannon index: SMD = -0.33, [95%CI = -0.48, -0.17]; Simpson index: SMD = -0.32, [95%CI = -0.49, -0.14]). However, when specific rheumatic diseases were examined, decreases were only observed in rheumatoid arthritis (observed species: SMD = -0.51, [95%CI = -0.78, -0.24]; Shannon index: SMD = -0.31, [95%CI = -0.49, -0.13]; Simpson index: SMD = -0.31, [95%CI = -0.54, -0.08]), systemic lupus erythematosus (Chao1: SMD = -1.60, [95%CI = -2.54, -0.66]; Shannon index: SMD = -0.63, [95%CI = -1.08, -0.18]), gout (Simpson index: SMD = -0.64, [95%CI = -1.07, -0.22]) and fibromyalgia (Simpson index: SMD = -0.28, [95%CI = -0.44, -0.11]), whereas an increase was observed in systemic sclerosis (Shannon index: SMD = 1.25, [95%CI = 0.09, 2.41]). Differences with statistical significance in ß-diversity were consistently reported in ankylosing spondylitis and IgG4-related diseases. Although little evidence of disease specificity of gut microbes was found, shared alterations of the depletion of anti-inflammatory butyrate-producing microbe (i.e., Faecalibacterium) and the enrichment of pro-inflammatory microbe (i.e., Streptococcus) were observed in rheumatoid arthritis, Sjögren's syndrome and systemic lupus erythematosus. INTERPRETATION: Gut microbiota dysbiosis was associated with rheumatic diseases, principally with potentially non-specific, shared alterations of microbes. FUNDING: National Natural Science Foundation of China (81930071, 81902265, 82072502 and U21A20352).

Hypoxia­induced circCCDC66 promotes the tumorigenesis of colorectal cancer via the miR­3140/autophagy pathway.

Circular RNAs (circRNAs) have been reported to be involved in the progression of colorectal cancer (CRC). However, the biological role of circCCDC66 in CRC remains unclear. Therefore, the present study aimed to elucidate the mechanisms through which circCCDC66 affects the hypoxia­induced progression of CRC. It was found that hypoxia promoted the progression of CRC and upregulated the expression of circCCDC66. Furthermore, circCCDC66­knockdown reduced viability, migration and invasion, and enhanced the apoptosis of hypoxia­exposed CRC cells. Using the starBase database, it was identified that circCCDC66 may bind to miR­3140. Subsequently, it was confirmed that circCCDC66 serves as a sponge of miR­3140 and the depletion of miR­3140 partly abolished the effects of circCCDC66 on the phenotype of hypoxia­exposed CRC cells. In addition, miR­3140 was validated to inhibit the autophagy pathway. The use of an autophagy inducer partially reversed the miR­3140 overexpression­induced inhibition of the viability and invasion, and the promotion of the apoptosis of hypoxia­exposed CRC cells. In summary, the findings of the present study demonstrated that circCCDC66 facilitates the development of CRC cells under hypoxic conditions via regulation of miR­3140/autophagy. These findings may provide a novel therapeutic option for patients with CRC.

Liver receptor homologue 1, a novel prognostic marker in colon cancer patients.

Liver receptor homologue 1 (LRH-1) is an orphan nuclear receptor that is highly expressed in a variety of cancer tissues, promotes tumor cell proliferation and metastasis, and is involved in the tumor cell cycle and apoptosis. The aim of the present study was to assess the association between the expression of LRH-1 and the prognosis of patients with colon cancer. Immunohistochemistry was used to detect the expression of LRH1 in 128 cases of colon cancer and adjacent tissues. The 5-year survival rate was obtained from telephone follow-up data, outpatient review and through access to medical records. Positive expression of LRH-1 was found in 108/128 colon cancer samples, compared with 17/128 normal tissues. Statistical analysis showed that positive LRH-1 expression was significantly associated with clinical pathological stage, depth of invasion and lymph node metastasis. The overall survival (OS) rate of patients with positive LRH-1 expression was significantly lower than that of patients with low expression. Multivariate analysis showed that LRH-1 expression could be used as an independent predictor of OS. In conclusion, the present findings suggest that LRH-1 may serve an important role in the development and progression of colon cancer, with potential value as a prognostic molecular marker that could be used to assist in the diagnosis and evaluation of colon cancer. LRH-1 may become a target for novel therapies for patients with colon cancer.

STrategically Acquired Gradient Echo (STAGE) imaging, part II: Correcting for RF inhomogeneities in estimating T1 and proton density.

PURPOSE: To develop a method for mapping the B1 transmit (B1t) and B1 receive (B1r) fields from two gradient echo datasets each with a different flip angle and from these two images obtain accurate T1 and proton density (PD) maps of the brain. METHODS: A strategically acquired gradient echo (STAGE) data set is collected using two flip angles each with multiple echoes. The B1t field extraction was based on forcing cortical gray matter and white matter to have specific T1 values and fitting the resulting B1t field to a quadratic function. The B1r field extraction was based on synthesizing isointense images despite there being two or three tissue types present in the brain. This method was tested on 10 healthy volunteers and 20 stroke patients from data acquired at 3.0Tesla. RESULTS: With the knowledge of the B1t and B1r fields, the uniformity of tissue T1 and PD maps was considerably improved. T1 values were measured for both the midbrain and basal ganglia and found to be in good agreement with the literature. DISCUSSION AND CONCLUSIONS: STAGE provides a practical way to assess the B1t and the B1r fields which can then be used to correct for spatial variations in the images.

COnstrained Data Extrapolation (CODE): A new approach for high definition vascular imaging from low resolution data.

PURPOSE: To introduce a new approach to reconstruct high definition vascular images using COnstrained Data Extrapolation (CODE) and evaluate its capability in estimating vessel area and stenosis. MATERIALS AND METHODS: CODE is based on the constraint that the full width half maximum of a vessel can be accurately estimated and, since it represents the best estimate for the width of the object, higher k-space data can be generated from this information. To demonstrate the potential of extracting high definition vessel edges using low resolution data, both simulated and human data were analyzed to better visualize the vessels and to quantify both area and stenosis measurements. The results from CODE using one-fourth of the fully sampled k-space data were compared with a compressed sensing (CS) reconstruction approach using the same total amount of data but spread out between the center of k-space and the outer portions of the original k-space to accelerate data acquisition by a factor of four. RESULTS: For a sufficiently high signal-to-noise ratio (SNR) such as 16 (8), we found that objects as small as 3 voxels in the 25% under-sampled data (6 voxels when zero-filled) could be used for CODE and CS and provide an estimate of area with an error <5% (10%). For estimating up to a 70% stenosis with an SNR of 4, CODE was found to be more robust to noise than CS having a smaller variance albeit a larger bias. Reconstruction times were >200 (30) times faster for CODE compared to CS in the simulated (human) data. CONCLUSION: CODE was capable of producing sharp sub-voxel edges and accurately estimating stenosis to within 5% for clinically relevant studies of vessels with a width of at least 3pixels in the low resolution images.

Effect of long-term proton pump inhibitor administration on gastric mucosal atrophy: A meta-analysis.

BACKGROUND/AIMS: Proton pump inhibitors (PPIs) are widely used for the treatment of acid-related gastrointestinal diseases. Recently, some studies have reported that PPIs can alter the gastric mucosal architecture; however, the relationship remains controversial. This meta-analysis study was designed to quantify the association between long-term PPI administration and gastric atrophy. MATERIALS AND METHODS: A PubMed search was conducted to identify studies using the keywords proton pump inhibitors or PPI and gastric atrophy or atrophic gastritis; the timeframe of publication searched was up to May 2016. Heterogeneity among studies was tested with the Q test; odds ratios (OR) and 95% confidence intervals (CI) were calculated. P values were calculated by I2 tests and regarded as statistically significant when <0.05. RESULTS: We identified 13 studies that included 1465 patients under long-term PPI therapy and 1603 controls, with a total gastric atrophy rate of 14.50%. There was a higher presence of gastric atrophy (15.84%; statistically significant) in PPI group compared to the control group (13.29%) (OR: 1.55, 95% CI: 1.00-2.41). CONCLUSIONS: The pooled data suggest that long-term PPI use is associated with increased rates of gastric atrophy. Large-scale multicenter studies should be conducted to further investigate the relationship between acid suppressants and precancerous diseases.

Effects of Sleeve Gastrectomy on Serum 12α-Hydroxylated Bile Acids in a Diabetic Rat Model.

BACKGROUND: Diabetes mellitus is a prevalent disease that endangers human health. Bariatric surgery can effectively relieve insulin resistance with elevated serum bile acids (BAs). 12α-Hydroxylated BAs were previously reported to be associated with insulin resistance. The aim of this study was to analyze changes in 12α-hydroxylated BA composition and possible associated mechanisms in diabetic rats following sleeve gastrectomy (SG). METHODS: SG and sham operations were performed in diabetic rats induced by high-fat diet feeding and streptozotocin. Body weight, food intake, oral glucose tolerance test (OGTT), insulin tolerance test (ITT), and serum BAs were analyzed at corresponding time points. Cholesterol 12α-hydroxylase (CYP8B1) and transcription factor V-Maf Avian Musculoaponeurotic Fibrosarcoma Oncogene Homolog G (MAFG) expression levels were assessed by RT-PCR and western blotting. RESULTS: Compared with the SHAM group, the SG group displayed significant weight loss from 6 weeks postoperatively, accompanied by decreased food intake from 4 weeks after the operation. At 2 and 12 weeks postoperatively, the areas under the curve of OGTT and ITT were significantly decreased in the SG group. At 12 weeks post-operation, the SG group displayed elevated serum BAs, but the percentage of 12α-hydroxylated BAs was reduced. Furthermore, SG rats exhibited higher MAFG and lower CYP8B1 protein and mRNA levels in the liver (P < 0.05). CONCLUSION: The percentage of 12α-hydroxylated bile acids was reduced after SG, which was relevant with the inhibition of CYP8B1 and overexpression of MAFG. These outcomes may play an important role in the improvement of insulin sensitivity following SG.

The efficacy of staple line reinforcement during laparoscopic sleeve gastrectomy: A meta-analysis of randomized controlled trials.

OBJECTIVE: This study was performed to evaluate the effects of staple line reinforcement during laparoscopic sleeve gastrectomy. METHODS: Relevant articles published in English (up to July 25, 2015) were identified by searching PubMed, Embase, Web of Knowledge. The outcomes of staple line hemorrhage and leakage, overall complications, operative time were pooled. Data synthesis and statistical analysis were performed using Stata 13.1 software. RESULTS: Eight randomized controlled trials involving 791 patients (453 cases and 338 controls) were analyzed. Compared to performing no reinforcement, staple line reinforcement was associated with a lower risk of staple line hemorrhage (RR = 0.609, 95%CI = 0.439-0.846, P = 0.003) and overall complications (RR = 0.673, 95%CI = 0.507-0.892, P = 0.006). No significant difference was observed regarding postoperative leakage (RR = 0.654, 95%CI = 0.275-1.555, P = 0.337). Oversewing of the staple line took longer operative time (WMD = 13.211, 95%CI = 6.192-20.229, P = 0.000). CONCLUSION: Staple line reinforcement using buttressing or roofing materials could reduce staple line hemorrhage and overall complications. No obvious advantages of oversewing the staple line were found and it took longer operative time. No significant reduction in leak rate was evidenced after reinforcement.

Effects of Bariatric Surgery on Serum Bile Acid Composition and Conjugation in a Diabetic Rat Model.

BACKGROUND: Serum bile acids (BAs) are elevated following bariatric surgery and have emerged as a potential glucose-lowering beneficial factor. The change of BA components and its underlying mechanisms may be of great significance during bariatric surgery. The aim of this study is to investigate the effects of different bariatric procedures on serum BA composition and explore the potential mechanisms using a diabetic rat model. METHODS: Duodenal-jejunal bypass (DJB), sleeve gastrectomy (SG), and sham operation were performed in diabetic rats induced by high-fat diet (HFD) and streptozotocin (STZ). Body weight, food intake, oral glucose tolerance test (OGTT), and insulin tolerance test (ITT) were measured at indicated time points. Serum BAs composition and the expression of cholesterol 7α hydroxylase (CYP7A1), bile acid: CoA synthase (BACS) and bile acid-CoA: amino acid N-acyltransferase (BAAT) at both transcriptional and protein levels in the liver were evaluated at 12 weeks postoperatively. RESULTS: Compared with sham group, DJB and SG both achieved rapid and sustained improvements in glucose tolerance and insulin sensitivity. They also resulted in increased serum BAs, especially the taurine-conjugated BAs by elevated conjugation. No obvious difference was detected between DJB and SG except that SG achieved decreased weight gain and food intake. CONCLUSIONS: The preferentially elevated serum taurine-conjugated BAs were similar after different bariatric surgeries, and the enhanced conjugation of BAs in the liver might account for the changed serum BAs profiles.

Evaluation of non-local means based denoising filters for diffusion kurtosis imaging using a new phantom.

Image denoising has a profound impact on the precision of estimated parameters in diffusion kurtosis imaging (DKI). This work first proposes an approach to constructing a DKI phantom that can be used to evaluate the performance of denoising algorithms in regard to their abilities of improving the reliability of DKI parameter estimation. The phantom was constructed from a real DKI dataset of a human brain, and the pipeline used to construct the phantom consists of diffusion-weighted (DW) image filtering, diffusion and kurtosis tensor regularization, and DW image reconstruction. The phantom preserves the image structure while minimizing image noise, and thus can be used as ground truth in the evaluation. Second, we used the phantom to evaluate three representative algorithms of non-local means (NLM). Results showed that one scheme of vector-based NLM, which uses DWI data with redundant information acquired at different b-values, produced the most reliable estimation of DKI parameters in terms of Mean Square Error (MSE), Bias and standard deviation (Std). The result of the comparison based on the phantom was consistent with those based on real datasets.

Image correction during large and rapid B(0) variations in an open MRI system with permanent magnets using navigator echoes and phase compensation.

An open permanent magnet system with vertical B(0) field and without self-shielding can be quite susceptible to perturbations from external magnetic sources. B(0) variation in such a system located close to a subway station was measured to be greater than 0.7 microT by both MRI and a fluxgate magnetometer. This B(0) variation caused image artifacts. A navigator echo approach that monitored and compensated the view-to-view variation in magnetic resonance signal phase was developed to correct for image artifacts. Human brain imaging experiments using a multislice gradient-echo sequence demonstrated that the ghosting and blurring artifacts associated with B(0) variations were effectively removed using the navigator method.