Exploring the phosphorus-starch content balance mechanisms in maize grains using GWAS population and transcriptome data.

Examining the connection between P and starch-related signals can help elucidate the balance between nutrients and yield. This study utilized 307 diverse maize inbred lines to conduct multi-year and multi-plot trials, aiming to explore the relationship among P content, starch content, and 100-kernel weight (HKW) of mature grains. A significant negative correlation was found between P content and both starch content and HKW, while starch content showed a positive correlation with HKW. The starch granules in grains with high-P and low-starch content (HPLS) were significantly smaller compared to grains with low-P high-starch content (LPHS). Additionally, mian04185-4 (HPLS) exhibited irregular and loosely packed starch granules. A significant decrease in ZmPHOs genes expression was detected in the HPLS line ZNC442 as compared to the LPHS line SCML0849, while no expression difference was observed in AGPase encoding genes between these two lines. The down-regulated genes in ZNC442 grains were enriched in nucleotide sugar and fatty acid anabolic pathways, while up-regulated genes were enriched in the ABC transporters pathway. An accelerated breakdown of fat as the P content increased was also observed. This implied that HPLS was resulted from elevated lipid decomposition and inadequate carbon sources. The GWAS analysis identified 514 significantly associated genes, out of which 248 were differentially expressed. Zm00001d052392 was found to be significantly associated with P content/HKW, exhibiting high expression in SCML0849 but almost no expression in ZNC442. Overall, these findings suggested new approaches for achieving a P-yield balance through the manipulation of lipid metabolic pathways in grains.

Genome-wide association studies dissect low-phosphorus stress response genes underling field and seedling traits in maize.

Phosphorus (P) is an essential element for plant growth, and its deficiency can cause decreased crop yield. This study systematically evaluated the low-phosphate (Pi) response traits in a large population at maturity and seedling stages, and explored candidate genes and their interrelationships with specific traits. The results revealed a greater sensitivity of seedling maize to low-Pi stress compared to that at maturity stage. The phenotypic response patterns to low-Pi stress at different stages were independent. Chlorophyll content was found to be a potential indicator for screening low-Pi-tolerant materials in the field. A total of 2900 and 1446 significantly associated genes at the maturity and seedling stages were identified, respectively. Among these genes, 972 were uniquely associated with maturity traits, while 330 were specifically detected at the seedling stage under low-Pi stress. Moreover, 768 and 733 genes were specifically associated with index values (low-Pi trait/normal-Pi trait) at maturity and seedling stage, respectively. Genetic network diagrams showed that the low-Pi response gene Zm00001d022226 was specifically associated with multiple primary P-related traits under low-Pi conditions. A total of 963 out of 2966 genes specifically associated with traits under low-Pi conditions or index values were found to be induced by low-Pi stress. Notably, ZmSPX4.1 and ZmSPX2 were sharply up-regulated in response to low-Pi stress across different lines or tissues. These findings advance our understanding of maize's response to low-Pi stress at different developmental stages, shedding light on the genes and pathways implicated in this response.

Gd-EOB-DTPA enhanced MRI based radiomics combined with clinical variables in stratifying hepatic functional reserve in HBV infected patients.

PURPOSES: To evaluate radiomics from Gd-EOB-DTPA enhanced MR combined with clinical variables for stratifying hepatic functional reserve in hepatitis B virus (HBV) patients. METHODS: Our study included 279 chronic HBV patients divided 8:2 for training and test cohorts. Radiomics features were extracted from the hepatobiliary phase (HBP) MR images. Radiomics features were selected to construct a Rad-score which was combined with clinical parameters in two models differentiating hepatitis vs. Child-Pugh A and Child-Pugh A vs. B/C. Performances of these stratifying models were compared using area under curve (AUC). RESULTS: Rad-score alone discriminated hepatitis vs. Child-Pugh A with AUC = 0.890, 0.914 and Child-Pugh A vs. B/C with AUC = 0.862, 0.865 for the training and test cohorts, respectively. Model 1 [Rad-score + clinical parameters for hepatitis vs. Child-Pugh A] showed AUC = 0.978 for the test cohort, which was higher than ALBI [albumin-bilirubin] and MELD [model for end-stage liver disease], with AUCs of 0.716, 0.799, respectively (p < 0.001, < 0.001). Model 2 [Rad-score + clinical parameters for Child-Pugh A vs. B/C] showed AUC of 0.890 in the test cohort, which was similar to ALBI (AUC = 0.908, p = 0.760), and higher than MELD (AUC = 0.709, p = 0.018). CONCLUSION: Rad-score combined with clinical variables stratifies hepatic functional reserve in HBV patients.

Portable Bulk-Water Disinfection by Live Capture of Bacteria with Divergently Branched Porous Graphite in Electric Fields.

Easy access to clean water is essential to functioning and development of modern society. However, it remains arduous to develop energy-efficient, facile, and portable water treatment systems for point-of-use (POU) applications, which is particularly imperative for the safety and resilience of society during extreme weather and critical situations. Here, we propose and validate a meritorious working scheme for water disinfection via directly capturing and removing pathogen cells from bulk water using strategically designed three-dimensional (3D) porous dendritic graphite foams (PDGFs) in a high-frequency AC field. The prototype, integrated in a 3D-printed portable water-purification module, can reproducibly remove 99.997% E. coli bacteria in bulk water at a few voltages with among the lowest energy consumption at 435.5 J·L-1. The PDGFs, costing $1.47 per piece, can robustly operate at least 20 times for more than 8 h in total without functional degradation. Furthermore, we successfully unravel the involved disinfection mechanism with one-dimensional Brownian dynamics simulation. The system is practically applied that brings natural water in Waller Creek at UT Austin to the safe drinking level. This research, including the working mechanism based on dendritically porous graphite and the design scheme, could inspire a future device paradigm for POU water treatment.

Pleural Effusions on MRI in Autosomal Dominant Polycystic Kidney Disease.

Autosomal dominant polycystic kidney disease (ADPKD) has cystic fluid accumulations in the kidneys, liver, pancreas, arachnoid spaces as well as non-cystic fluid accumulations including pericardial effusions, dural ectasia and free fluid in the male pelvis. Here, we investigate the possible association of ADPKD with pleural effusion. ADPKD subjects (n = 268) and age-gender matched controls without ADPKD (n = 268) undergoing body magnetic resonance imaging from mid-thorax down into the pelvis were independently evaluated for pleural effusion by 3 blinded expert observers. Subjects with conditions associated with pleural effusion were excluded from both populations. Clinical and laboratory data as well as kidney, liver and spleen volume, pleural fluid volume, free pelvic fluid and polycystic kidney disease genotype were evaluated. Pleural effusions were observed in 56 of 268 (21%) ADPKD subjects compared with 21 of 268 (8%) in controls (p < 0.0001). In a subpopulation controlling for renal function by matching estimated glomerular filtration rate (eGFR), 28 of 110 (25%) ADPKD subjects had pleural effusions compared to 5 of 110 (5%) controls (p < 0.001). Pleural effusions in ADPKD subjects were more prevalent in females (37/141; 26%) than males (19/127,15%; p = 0.02) and in males were weakly correlated with the presence of free pelvic fluid (r = 0.24, p = 0.02). ADPKD subjects with pleural effusions were younger (48 ± 14 years old vs. 43 ± 14 years old) and weighed less (77 vs. 70 kg; p ≤ 0.02) than those without pleural effusions. For ADPKD subjects with pleural effusions, the mean volume of fluid layering dependently in the posterior−inferior thorax was 19 mL and was not considered to be clinically significant. Pleural effusion is associated with ADPKD, but its role in the pathogenesis of ADPKD requires further evaluation.

Fluid Mechanics Approach to Perfusion Quantification: Vasculature Computational Fluid Dynamics Simulation, Quantitative Transport Mapping (QTM) Analysis of Dynamics Contrast Enhanced MRI, and Application in Nonalcoholic Fatty Liver Disease Classification.

OBJECTIVE: We quantify liver perfusion using quantitative transport mapping (QTM) method that is free of arterial input function (AIF). QTM method is validated in a vasculature computational fluid dynamics (CFD) simulation and is applied for processing dynamic contrast enhanced (DCE) MRI images in differentiating liver with nonalcoholic fatty liver disease (NAFLD) from healthy controls using pathology reference in a preclinical rabbit model. METHODS: QTM method was validated on a liver perfusion simulation based on fluid dynamics using a rat liver vasculature model and the mass transport equation. In the NAFLD grading task, DCE MRI images of 7 adult rabbits with methionine choline-deficient diet-induced nonalcoholic steatohepatitis (NASH), 8 adult rabbits with simple steatosis (SS) were acquired and processed using QTM method and dual-input two compartment Kety's method respectively. Statistical analysis was performed on six perfusion parameters: velocity magnitude | u | derived from QTM, liver arterial blood flow LBFa, liver venous blood flow LBFv, permeability Ktrans, blood volume Vp and extravascular space volume Ve averaged in liver ROI. RESULTS: In the simulation, QTM method successfully reconstructed blood flow, reduced error by 48% compared to Kety's method. In the preclinical study, only QTM |u| showed significant difference between high grade NAFLD group and low grade NAFLD group. CONCLUSION: QTM postprocesses DCE-MRI automatically through deconvolution in space and time to solve the inverse problem of the transport equation. Comparing with Kety's method, QTM method showed higher accuracy and better differentiation in NAFLD classification task. SIGNIFICANCE: We propose to apply QTM method in liver DCE MRI perfusion quantification.

The convergent and divergent patterns in brain perfusion between Alzheimer's disease and Parkinson's disease with dementia: An ASL MRI study.

Background: Aberrant brain blood perfusion changes have been found to play an important role in the progress of Alzheimer's disease (AD) and Parkinson's disease with dementia (PDD). However, the convergent and divergent patterns in brain perfusion between two dementias remain poorly documented. Objective: To explore the impaired brain perfusion pattern and investigate their overlaps and differences between AD and PDD using normalized cerebral blood flow (CBF). Methods: The regional perfusion in patients with AD and PDD as well as healthy control (HC) subjects were explored using the three-dimensional arterial spin labeling. The normalized CBF values were compared across the three groups and further explored the potential linkages to clinical assessments. Results: In total, 24 patients with AD, 26 patients with PDD, and 35 HC subjects were enrolled. Relative to the HC group, both the AD group and the PDD group showed reduced normalized CBF mainly in regions of the temporal and frontal gyrus, whereas preserved perfusion presented in the sensorimotor cortex and basal ganglia area. Compared with the AD group, the PDD group showed decreased perfusion in the right putamen and right supplementary motor area (SMA), while preserved perfusion in the right inferior parietal lobule (IPL) and right precuneus. In the AD group, significant correlations were observed between the normalized CBF values in the right IPL and scores of global cognitive function (P = 0.033, ρ = 0.442), between the normalized CBF values in the right precuneus and the scores of memory function (P = 0.049,ρ = 0.406). The normalized CBF in the right putamen was significantly linked to cores of motor symptoms (P = 0.017, ρ = 0.214) in the PDD group. Conclusion: Our findings suggested convergent and divergent patterns of brain hemodynamic dysregulation between AD and PDD and contributed to a better understanding of the pathophysiological mechanisms.

The altered functional modular organization in systemic lupus erythematosus: an independent component analysis study.

The aim of this study was to investigate the abnormities in functional connectivity (FC) within each modular network and between modular networks in patients with systemic lupus erythematosus (SLE). Twelve meaningful modular networks were identified via independent component analysis from 41 patients and 40 volunteers. Parametric tests were used to compare the intra- and intermodular FC between the groups. Partial correlation analysis was used to seek the relationships between abnormal FCs and the clinical data. Compared to the controls, SLE patients showed decreased intramodular FC in the anterior default mode network (aDMN), posterior default mode network (pDMN), ventral attention network (VAN), and sensorimotor network (SMN) and increased intramodular FC in the medial visual network (mVN) and left frontoparietal network. In addition, SLE patients showed decreased intermodular FC between the SMN and the lateral visual network (lVN), between the SMN and the VAN, and between the pDMN and the lVN and exhibited increased intermodular FC between the SMN and the salience network (SAN), between the pDMN and the SAN, and between the aDMN and the VAN. Moreover, we found several correlations among the abnormal FCs and the Mini-Mental State Examination in SLE patients. Mild cognitive impairment is compensated by the hyperconnectivity between the aDMN and the VAN, while severe cognitive impairment tends to be compensated by the hyperconnectivity between the SMN and the SAN. The FC value between the SMN and the SAN and between the aDMN and the VAN may serve as neuroimaging markers for monitoring cognitive progression in SLE patients.

The central vein sign in multiple sclerosis lesions: Susceptibility relaxation optimization from a routine MRI multiecho gradient echo sequence.

BACKGROUND AND PURPOSE: The white matter lesion central vein sign (CVS) is an emerging biomarker for multiple sclerosis (MS) differential diagnosis. Currently, CVS is detected on susceptibility weighted imaging (SWI) with suboptimal contrast. We developed an imaging method called susceptibility relaxation optimization (SRO) to improve CVS visualization. METHODS: This was a retrospective study of MS patients who had MRI in June 2018 with routine 3D multiecho gradient echo (GRE) and T2-weighted fluid-attenuated inversion recovery (FLAIR) sequences. SRO and SWI images were reconstructed from GRE data. MS lesions were identified on FLAIR image. The CVS detection rate, the image quality score of CVS conspicuity (range 0-3), and central vein-to-lesion contrast were compared between SRO and SWI images. RESULTS: In 20 MS patients (mean age 45 ± 9 years; 15 women), SRO significantly increased CVS detection rate compared to SWI (53.3%, 274/514 vs. 32.9%, 169/514; p<.001, McNemar's test). The median image quality score for SRO was 2 compared to 1 for SWI (p<.001, Wilcoxon signed-rank test). The median overall image quality score for SRO was 7 compared to 6 for SWI (p = .003; Wilcoxon signed-rank test). Central vein-to-lesion contrast was 0.12 ± 0.12 in SRO compared to 0.031 ± 0.075 in SWI (p<.001, t-test). CONCLUSIONS: SRO yields better central vein contrast and increases CVS detection rate compared to SWI.

Brain oxygen extraction fraction mapping in patients with multiple sclerosis.

We aimed to demonstrate the feasibility of whole brain oxygen extraction fraction (OEF) mapping for measuring lesion specific and regional OEF abnormalities in multiple sclerosis (MS) patients. In 22 MS patients and 11 healthy controls (HC), OEF and neural tissue susceptibility (χn) maps were computed from MRI multi-echo gradient echo data. In MS patients, 80 chronic active lesions with hyperintense rim on quantitative susceptibility mapping were identified, and the mean OEF and χn within the rim and core were compared using linear mixed-effect model analysis. The rim showed higher OEF and χn than the core: relative to their adjacent normal appearing white matter, OEF contrast = -6.6 ± 7.0% vs. -9.8 ± 7.8% (p < 0.001) and χn contrast = 33.9 ± 20.3 ppb vs. 25.7 ± 20.5 ppb (p = 0.017). Between MS and HC, OEF and χn were compared using a linear regression model in subject-based regions of interest. In the whole brain, compared to HC, MS had lower OEF, 30.4 ± 3.3% vs. 21.4 ± 4.4% (p < 0.001), and higher χn, -23.7 ± 7.0 ppb vs. -11.3 ± 7.7 ppb (p = 0.018). Our feasibility study suggests that OEF may serve as a useful quantitative marker of tissue oxygen utilization in MS.

Simultaneous hepatic iron and fat quantification with dual-energy CT in a rabbit model of coexisting iron and fat.

BACKGROUND: Liver iron and fat are often co-deposited, synergistically aggravating the progression of chronic liver disease. Accurate determination of liver iron and fat content is helpful for patient management. To assess the accuracy of hepatic iron/fat decomposition using dual-energy computed tomography (DECT) for simultaneously quantifying hepatic iron and fat when both are present. METHODS: Sixty-eight New Zealand rabbits on a high-fat/cholesterol diet plus iron injections were used to establish a model of coexisting hepatic iron/fat. Abdominal imaging was performed using dual-source DECT. The iron and fat fractions (Iron-CT and Fat-CT, respectively) were calculated using a 3-material decomposition algorithm. The spectroscopic liver iron concentration (LIC) grading (normal, mild, moderate, severe, and massive iron overload) and the histopathological fat fraction (Fat-ref) grading (normal, mild, moderate, severe steatosis) were used as references. Correlations between the DECT parameters and the references were analyzed. Hepatic iron/fat quantification equations were established and validated. Analysis of covariance was used to assess the influence of fat on iron measurements and vice versa. RESULTS: Iron-CT highly correlated with LIC (r=0.94, P<0.001), and Fat-CT highly correlated with Fat-ref (r=0.88, P<0.001). Both the Iron-CT- and Fat-CT-derived LIC and fat fraction showed good agreement with spectroscopy/histology. The linear relationship between Iron-CT and spectroscopic LIC was not affected by the grade of hepatic fat (F=1.93, P=0.16). The linear relationship between Fat-CT and Fat-ref was unaffected by hepatic iron grades from normal to severe (F=0.18, P=0.91). However, with massive iron overload [>15.0 mg Fe/g (270 µmol/g)] the regression began to deviate, causing fat underestimation (F=5.50, P=0.04). CONCLUSIONS: Our DECT-based iron/fat decomposition algorithm accurately measured hepatic iron and fat when both were present in a rabbit model. Hepatic fat may be underestimated when there is massive iron overload.

Can Hybrid Arterial Spin Labeling-Tagged Zero-Echo-Time Magnetic Resonance Angiography Be an Effective Candidate in the Evaluation of Intracranial Artery Diseases? A Clinical Feasibility Study.

BACKGROUND: Flow related artifacts in continuous arterial spin labeling (cASL) zero-echo-time (ZTE) magnetic resonance angiography (MRA) could influence the vasculature visualization. PURPOSE: To investigate the clinical feasibility for the intracranial artery diseases assessment by utilizing hybrid ASL-ZTE-MRA (hASL-ZTE-MRA). STUDY TYPE: Prospective, technical development. POPULATION: Sixty-seven subjects with known/suspected cerebrovascular diseases. FIELD STRENGTH/SEQUENCE: Gradient echo based cASL-/hASL- ZTE-MRA at 3.0 T. ASSESSMENT: Subjective/objective evaluation for sound-levels. Image quality (IQ), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were analyzed within artery segments. Stenotic grading, aneurysm measurement, and signal intensity of lesions were further analyzed. STATISTICAL TESTS: Kolmogorov-Smirnov test for data normality check. Between two MRAs: Wilcoxon signed-rank test for sound experience/IQ ratings analysis; Paired t test for SNR/CNR comparison. One-way analysis of variance for sound intensity comparison. For stenosis grading/aneurysm measurement: Kendall's W test/intraclass correlation coefficient (ICC) for interobserver agreement test within each modality, weighted kappa statistics/ICC for intermodality agreement test between each MRA and computed tomography angiography. RESULTS: Sound-level perception/intensity was similar (P = 0.86, P = 0.55) between MRAs. The mean IQ score for hASL-ZTE-MRA was on diagnostic scale and slightly higher (P < 0.05) than that of cASL-ZTE-MRA. hASL-ZTE-MRA provided higher (P < 0.05) SNR/CNR than that of cASL-ZTE-MRA. Signal uniformity was improved on hASL-ZTE-MRA, particularly among the anterior circulation (P < 0.05). Comparing to cASL-ZTE-MRA, on hASL-ZTE-MRA, stenotic lesions were accurately assessed; flow in the stent or aneurysm remnant was better depicted (P < 0.05); AVM nidus was preferred with increased SNR (P < 0.05). No significant differences for the aneurysm measurement were found between MRAs (P = 0.95), in addition to the slightly higher SNR (P < 0.05) on hASL-ZTE-MRA. DATA CONCLUSION: Comparing to cASL-ZTE-MRA, hASL-ZTE-MRA is robust and feasible for the evaluation of intracranial artery diseases with diagnostic IQ, improved vessel contrast, and better signal heterogeneity. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: 2.

Prevalence of Inferior Vena Cava Compression in ADPKD.

INTRODUCTION: Kidney and liver cysts in autosomal dominant polycystic kidney disease (ADPKD) can compress the inferior vena cava (IVC), but IVC compression prevalence and its risk factors are unknown. METHODS: Patients who have ADPKD (n = 216) with abdominal magnetic resonance imaging (MRI) studies and age-/sex-matched controls (n = 216) were evaluated for IVC compression as well as azygous vein diameter (a marker of collateral blood flow) and IVC aspect ratio (left-to-right dimension divided by anterior-to-posterior dimension with a value of 1 corresponding to a circular (high pressure) IVC caudal to compression. RESULTS: Severe IVC compression (≥70%) was observed in 33 (15%) ADPKD subjects and mild compression (≥50% to <70%) was observed in 33 (15%) subjects; whereas controls had no IVC compression (P < 0.001). Severe IVC compression was associated with larger azygous vein (4.0 ± 1.3 mm versus 2.3 ± 0.8 mm without IVC compression; P < 0.001) and a more circular IVC cross-section upstream (mean IVC aspect ratio: 1.16 ± 0.27 vs. 1.69 ± 0.67, P < 0.001), suggesting higher pressure upstream from the compression. IVC compression was associated with older age, lower estimated glomerular filtration rate (eGFR), greater height-adjusted total kidney volumes, greater height-adjusted liver volume (ht-LV), and greater liver and renal cyst fractions (P < 0.001). No subject younger than 30 years had IVC compression, but ADPKD subjects ≥40 years old had 12-fold higher risk of IVC compression (95% confidence interval [CI]: 4.2-42.4), with highest predicted probability for Mayo Clinic classes 1D (59%; 95% CI: 39%-76%) and 1E (74%; 95% CI: 49%-90%) after adjustment (P < 0.001). Women with ht-LV ≥ 2000 ml/m had 83% (95% CI: 59%-95%) prevalence of IVC compression. Complications of IVC compression included deep vein thrombosis (DVT) and symptomatic hypotension. CONCLUSIONS: IVC compression is common in ADPKD patients >40 years old, with Mayo Clinic class 1D/E, and in females with ht-LV > 2000 ml/m.

Deep neural network for water/fat separation: Supervised training, unsupervised training, and no training.

PURPOSE: To use a deep neural network (DNN) for solving the optimization problem of water/fat separation and to compare supervised and unsupervised training. METHODS: The current T2∗ -IDEAL algorithm for solving water/fat separation is dependent on initialization. Recently, DNN has been proposed to solve water/fat separation without the need for suitable initialization. However, this approach requires supervised training of DNN using the reference water/fat separation images. Here we propose 2 novel DNN water/fat separation methods: 1) unsupervised training of DNN (UTD) using the physical forward problem as the cost function during training, and 2) no training of DNN using physical cost and backpropagation to directly reconstruct a single dataset. The supervised training of DNN, unsupervised training of DNN, and no training of DNN methods were compared with the reference T2∗ -IDEAL. RESULTS: All DNN methods generated consistent water/fat separation results that agreed well with T2∗ -IDEAL under proper initialization. CONCLUSION: The water/fat separation problem can be solved using unsupervised deep neural networks.

[Effects of Different Rotation Patterns of Oil-Rice on Methane and Nitrous Oxide Emissions in Rice Fields].

A field experiment was carried out to investigate the effects of different rice-rape rotation systems on methane and nitrous oxide emissions, which were measured using the static chamber/gas chromatography method, prediction of their global warming potentials (GWP), and greenhouse gas intensity (GHGI) in paddy fields. The results showed that the average cumulative emissions of CH4from a double cropping paddy field, single season rice field (including middle or late), rape field, and leisure land were 135.25, 55.64, 5.05, and 1.89 kg ·hm-2, respectively. The CH4 emission during the rice season accounted for 91.8%-98.5% of the annual CH4 emission in different rotation years, and the contents of dissolved organic carbon in paddy soil exhibited a significantly positive correlation with CH4 emission. The CH4 emission in conventional late rice paddy was 18.7% higher than that of hybrid late rice paddy (P<0.05). The average cumulative emissions of N2O from double cropping paddy field, single season rice field (including middle or late), rape field, and leisure land were 0.94, 0.64, 1.38, and 0.24 kg ·hm-2, respectively. Out of the total annual N2O emission, 57.2% to 70.2% was from the rape field; 17.8% and 30.6% was due to the winter fallow treatments with previous crop type of double corpping rice and single season rice, respectively. There was no significant difference in N2O emission between hybrid rice and conventional rice paddy fields. The GWP of double cropping rice-winter fallow and double cropping rice-rape was higher than that of rice-rape and rice-winter fallow, and the GWP of CH4 in rice season accounted for 71.2% to 90.9% of the annual GWP of rotation. The highest treatment of GHGI was rice-rice-rape, and the treatment of rice-oil and rice-winter slack was lower. According to the comprehensive environmental and economic benefits, the late hybrid rice-rape patterns should be selected to reduce greenhouse gases in multiple cropping rice fields of South China.

Comparing mono-exponential, bi-exponential, and stretched-exponential diffusion-weighted MR imaging for stratifying non-alcoholic fatty liver disease in a rabbit model.

OBJECTIVES: To compare diffusion parameters obtained from mono-exponential, bi-exponential, and stretched-exponential diffusion-weighted imaging (DWI) in stratifying non-alcoholic fatty liver disease (NAFLD). METHODS: Thirty-two New Zealand rabbits were fed a high-fat/cholesterol or standard diet to obtain different stages of NAFLD before 12 b-values (0-800 s/mm2) DWI. The apparent diffusion coefficient (ADC) from the mono-exponential model; pure water diffusion (D), pseudo-diffusion (D*), and perfusion fraction (f) from bi-exponential DWI; and distributed diffusion coefficient (DDC) and water molecular diffusion heterogeneity index (α) from stretched-exponential DWI were calculated for hepatic parenchyma. The goodness of fit of the three models was compared. NAFLD severity was pathologically graded as normal, simple steatosis, borderline, and non-alcoholic steatohepatitis (NASH). Spearman rank correlation analysis and receiver operating characteristic curves were used to assess NAFLD severity. RESULTS: Upon comparison, the goodness of fit chi-square from stretched-exponential fitting (0.077 ± 0.012) was significantly lower than that for the bi-exponential (0.110 ± 0.090) and mono-exponential (0.181 ± 0.131) models (p < 0.05). Seven normal, 8 simple steatosis, 6 borderline, and 11 NASH livers were pathologically confirmed from 32 rabbits. Both α and D increased with increasing NAFLD severity (r = 0.811 and 0.373, respectively; p < 0.05). ADC, f, and DDC decreased as NAFLD severity increased (r = - 0.529, - 0.717, and - 0.541, respectively; p < 0.05). Both α (area under the curve [AUC] = 0.952) and f (AUC = 0.931) had significantly greater AUCs than ADC (AUC = 0.727) in the differentiation of NASH from borderline or less severe groups (p < 0.05). CONCLUSIONS: Stretched-exponential DWI with higher fitting efficiency performed, as well as bi-exponential DWI, better than mono-exponential DWI in the stratification of NAFLD severity. KEY POINTS: • Stretched-exponential diffusion model fitting was more reliable than the bi-exponential and mono-exponential diffusion models (p = 0.039 and p < 0.001, respectively). • As NAFLD severity increased, the diffusion heterogeneity index (α) increased, while the perfusion fraction (f) decreased (r = 0.811, - 0.717, p < 0.05). • Both α and f showed superior NASH diagnostic performance (AUC = 0.952, 0.931) compared with ADC (AUC = 0.727, p < 0.05).

Benefits of Silent DWI MRI in Success Rate, Image Quality, and the Need for Secondary Sedation During Brain Imaging of Children of 3-36 Months of Age.

RATIONALE AND OBJECTIVES: Silent T1W and T2W magnetic resonance imaging (MRI) can be used to study myelination in children, but the success rate of silent diffusion-weighted imaging is unknown. This study aimed to evaluate the success rate and image quality of silent MRI for the brain of children. MATERIALS AND METHODS: This was a retrospective study of 3-36-month children who underwent silent or conventional brain MRI at the People's Hospital of Northern Jiangsu from 01/2015 to 02/2018. The success rates were compared. The acoustic noise of each sequence was measured using a decibel meter. The signal-to-noise ratio and contrast-to-noise ratio of the diffusion-weighted imaging, T2W, and T1W sequences were analyzed. Subjective image quality (lesion delineation, visibility, gray-white differentiation, and overall diagnostic usefulness) was determined. RESULTS: The success rate of silent MRI (n = 443) was higher than that of conventional MRI (n = 391) (97.7% vs. 88.2%, p < 0.001). The acoustic noise of all silent sequences was lower than that of the conventional sequence (all p < 0.05). Silent sequences showed decreased signal-to-noise ratio vs. conventional sequences but increased contrast-to-noise ratio (all p < 0.05). Lesion delineation was not significantly different. Lesion visibility and gray-white differentiation of all silent sequences were higher (all p < 0.05). The overall diagnostic usefulness of the silent group was higher (p < 0.001). CONCLUSION: Silent MRI can effectively improve the success rate of MRI in children of 3-36 months. Noise is reduced, and the overall diagnostic usefulness is higher than that of conventional MRI. Silent MRI is more suitable for children's brain scan than conventional MRI.

Evaluation of diffusion kurtosis imaging in stratification of nonalcoholic fatty liver disease and early diagnosis of nonalcoholic steatohepatitis in a rabbit model.

PURPOSE: To examine the feasibility of MR diffusion kurtosis imaging (DKI) for characterizing nonalcoholic fatty liver disease (NAFLD) and diagnosing nonalcoholic steatohepatitis (NASH). METHODS: Thirty-two rabbits on high fat diet with different severities of NAFLD were imaged at 3 T MR including diffusion weighted imaging (DWI) and DKI using b values of 0, 400, 800 s/mm2 with 15 diffusion directions at each b value. Apparent diffusion coefficient (ADC) was derived from the linear exponential DWI model. Mean diffusion (MD) and mean kurtosis (MK) were derived from the quadratic exponential model of DKI. Correlations between MR parameters and hepatic pathology determined by the NAFLD activity scoring system were analyzed by Spearman rank correlation analysis. Receiver operating characteristic analyses were applied to determine the cutoff values of MD, MK as well as ADC in distinguishing NASH from non-NASH. The diagnostic efficacies of MD and MK in detecting NASH were compared with that of ADC. RESULTS: Values for ADC and MD significantly decreased as the severity of NAFLD increased (ρ = -0.529, -0.904, respectively; P < 0.05). MK values significantly increased as the severity of NAFLD increased (ρ = 0.761; P < 0.05). In addition, both MD and MK values were significantly different between borderline NASH and NASH groups (MD: 1.729 ±â€¯0.144 vs. 1.458 ±â€¯0.240[×10-3 mm2/s]; MK: 1.096 ±â€¯0.079 vs. 1.237 ±â€¯0.180; P < 0.05). Moreover, there was a significantly higher area under the curve (AUC) for both MD (0.955) and MK (0.905), as compared to ADC (0.736). CONCLUSION: Diffusion kurtosis imaging was feasible for stratifying NAFLD, and more accurately discriminated NASH from non-NASH when compared with DWI.

Follow-up assessment of coiled intracranial aneurysms using zTE MRA as compared with TOF MRA: a preliminary image quality study.

OBJECTIVES: To prospectively assess coiled intracranial aneurysms using a novel non-contrast enhanced zero echo time (zTE) MR angiography (MRA) method, and compare its image quality with time-of-flight (TOF) MRA, using digital subtraction angiography (DSA) as reference. METHODS: Twenty-five patients (10 males and 15 females; age 53.96 ± 12.46 years) were enrolled in this monocentric study. MRA sequences were performed 24 h before DSA. Susceptibility artefact intensity and flow signal within the parent artery were carried out using a 4-point scale. Occlusion status was assessed using the 3-grade Montreal scale. RESULTS: Scores of zTE were higher than TOF for both susceptibility artefact intensity (3.42 ± 0.64, 2.92 ± 0.63, P = 0.01) and flow signal (3.66 ± 0.95, 3.24 ± 1.24, P = 0.01). DSA revealed 17 complete occlusions, five residual neck aneurysms and two residual aneurysms. Inter-observer agreement was excellent (weighted κ: 0.89) for zTE and good (weighted κ: 0.68) for TOF. Intermodality agreement was excellent for zTE (weighted κ: 0.95) and good for TOF (weighted κ: 0.80). Correlations of both MRA sequences with DSA were high (zTE, Spearman's ρ: 0.91; TOF, Spearman's ρ: 0.81). CONCLUSIONS: zTE MRA showed promising results for follow-up assessment of coiled intracranial aneurysms and was superior to TOF MRA for visualizing the parent artery and evaluating occlusion status. KEY POINTS: • Various MRA sequences were applied for follow-up assessment of coiled intracranial aneurysms. • zTE MRA was less sensitive to susceptibility artefacts and haemodynamics. • In this monocentric study, zTE MRA was equivalent to DSA. • zTE MRA maybe an alternative to TOF MRA for follow-up assessment.

Biodegradable yolk-shell microspheres for ultrasound/MR dual-modality imaging and controlled drug delivery.

A new class of uniform biodegradable yolk-shell Fe3O4@PFH@PMAA-DOX microspheres was developed as ultrasound/MR dual-modality imaging contrast agents and drug delivery system. PMAA shells exhibit excellent drug loading capability and efficiency, the DOX-loading capacity is 15.4wt% and the drug loading efficiency is 91%. In vivo ultrasound and MRI experiments indicate that the as-prepared Fe3O4@PFH@PMAA-DOX microspheres successfully reach tumor tissues and possess robust dual-modality imaging capability, the r2 value of MRI is 71.82mM-1s-1. In vitro cytotoxicity and in vivo tissues biopsies show that the loaded DOX can be control-released under pH, redox and ultrasound multi-stimuli and kill cancer cells effectively. Furthermore, disulfide-crosslinked PMAA shells and PGA-stabilized Fe3O4 cores can be respectively degraded into short hydrophilic polymer chains and iron ions, reducing their cumulative toxicity in organisms. Thus, the multifunctional biodegradable microspheres are safer for normal tissues and more beneficial in actual clinical applications.