Publications by authors named "Yanhua Duan"

45 Publications

A 2D-3D hybrid convolutional neural network for lung lobe auto-segmentation on standard slice thickness computed tomography of patients receiving radiotherapy.

Biomed Eng Online 2021 Sep 23;20(1):94. Epub 2021 Sep 23.

Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.

Background: Accurate segmentation of lung lobe on routine computed tomography (CT) images of locally advanced stage lung cancer patients undergoing radiotherapy can help radiation oncologists to implement lobar-level treatment planning, dose assessment and efficacy prediction. We aim to establish a novel 2D-3D hybrid convolutional neural network (CNN) to provide reliable lung lobe auto-segmentation results in the clinical setting.

Methods: We retrospectively collected and evaluated thorax CT scans of 105 locally advanced non-small-cell lung cancer (NSCLC) patients treated at our institution from June 2019 to August 2020. The CT images were acquired with 5 mm slice thickness. Two CNNs were used for lung lobe segmentation, a 3D CNN for extracting 3D contextual information and a 2D CNN for extracting texture information. Contouring quality was evaluated using six quantitative metrics and visual evaluation was performed to assess the clinical acceptability.

Results: For the 35 cases in the test group, Dice Similarity Coefficient (DSC) of all lung lobes contours exceeded 0.75, which met the pass criteria of the segmentation result. Our model achieved high performances with DSC as high as 0.9579, 0.9479, 0.9507, 0.9484, and 0.9003 for left upper lobe (LUL), left lower lobe (LLL), right upper lobe (RUL), right lower lobe (RLL), and right middle lobe (RML), respectively. The proposed model resulted in accuracy, sensitivity, and specificity of 99.57, 98.23, 99.65 for LUL; 99.6, 96.14, 99.76 for LLL; 99.67, 96.13, 99.81 for RUL; 99.72, 92.38, 99.83 for RML; 99.58, 96.03, 99.78 for RLL, respectively. Clinician's visual assessment showed that 164/175 lobe contours met the requirements for clinical use, only 11 contours need manual correction.

Conclusions: Our 2D-3D hybrid CNN model achieved accurate automatic segmentation of lung lobes on conventional slice-thickness CT of locally advanced lung cancer patients, and has good clinical practicability.
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http://dx.doi.org/10.1186/s12938-021-00932-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8461922PMC
September 2021

Dosimetric effect of intensity-modulated radiation therapy for postoperative non-small cell lung cancer with and without air cavity in the planning target volume.

Med Dosim 2021 Sep 19. Epub 2021 Sep 19.

Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China. Electronic address:

To evaluate the dosimetric effect of intensity-modulated radiation therapy (IMRT) for postoperative non-small cell lung cancer (NSCLC), with and without the air cavity in the planning target volume (PTV). Two kinds of IMRT plans were made for 21 postoperative NSCLC patients. In Plan-0: PTV included the tracheal air cavity, and in Plan-1: the air cavity was subtracted from the PTV. For PTV, the dosimetric parameters, including D, D, D, D, D, conformity index (CI), and homogeneity index (HI) were evaluated. For organs at risk (OARs), the evaluation indexes, included the V, V and the mean lung dose (MLD) of total lung, the V, V, and the mean heart dose (MHD) of heart, the spinal cord D, and the V and the mean esophageal dose (MED) of esophagus. The number of segments and MUs were also recorded. Additionally, the correlation between the Plan-1 dosimetric change value relative to Plan-0, the size of air cavity, and the volume proportion of the cavity in the PTV was also analyzed. The D of PTV, D, D, HI and CI in Plan-1 decreased compared with those in Plan-0. For OARs, the V, MHD, and MED also decreased. The CI change value of Plan-1 relative to Plan-0 had a significantly negative correlation with the size and the volume proportion of air cavity, and the MED change value also had a significantly negative correlation with the air cavity size. The IMRT plans for patients with postoperative NSCLC can achieve a better target dose distribution and offer an improved sparing of the heart and esophagus by removing the PTV air cavity, while reducing the target conformity. The change value of CI and MED had a significantly negative correlation with the air cavity size.
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http://dx.doi.org/10.1016/j.meddos.2021.07.005DOI Listing
September 2021

Dosimetric Comparison, Treatment Efficiency Estimation, and Biological Evaluation of Popular Stereotactic Radiosurgery Options in Treating Single Small Brain Metastasis.

Front Oncol 2021 5;11:716152. Epub 2021 Aug 5.

Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.

Objectives: This study aimed to show the advantages of each stereotactic radiosurgery (SRS) treatment option for single small brain metastasis among Gamma Knife (GK), Cone-based VMAT (Cone-VMAT), and MLC-based CRT (MLC-CRT) plans.

Materials And Methods: GK, Cone-VMAT, and MLC-CRT SRS plans were retrospectively generated for 11 patients with single small brain metastasis whose volume of gross tumor volume (GTV) ranged from 0.18 to 0.76 cc (median volume 0.60 cc). Dosimetric parameters, treatment efficiency, and biological parameters of the three techniques were compared and evaluated. The metric variation with the planning target volume (PTV) was also studied.

Results: The conformity index (CI) was similar in GK and MLC-CRT plans, higher than Cone-VMAT. Cone-VMAT achieved comparable volume covered by 12 Gy (V12) and gradient index (GI) as GK, lower than MLC-CRT. The heterogeneity index (HI) of GK, Cone-VMAT, and MLC-CRT decreased sequentially. GK gave the lowest volume covered by 3 Gy (V3) and 6 Gy (V6), while MLC-CRT got the highest. The beam-on time and treatment time of GK, Cone-VMAT, and MLC-CRT decreased in turn. Tumor control probability (TCP) of all three SRS plans was greater than 98%, and normal tissue complication probability (NTCP) of all organs at risk (OARs) was below 0.01%. GK and Cone-VMAT resulted in superior TCP and NTCP of the normal brain tissue than MLC-CRT. The relative value of Cone-VMAT and GK for all metrics hardly changed with the target volume. Except for the unchanged HI and TCP, the other results of MLC-CRT with respect to GK improved as the target volume increased. MLC-CRT could produce higher CI than GK and Cone-VMAT when the target volume increased above 2 and 1.44 cc, respectively.

Conclusion: For single small brain metastases, Cone-VMAT may be used as an alternative to GK-free centers. In addition to the advantage of short treatment time, MLC-CRT showed superiority in CI as the target volume increased. Treatment centers can choose appropriate SRS technique on a case-by-case basis according to institutional conditions and patients' individual needs.
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http://dx.doi.org/10.3389/fonc.2021.716152DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8447903PMC
August 2021

Dosimetric comparison and biological evaluation of fixed-jaw intensity-modulated radiation therapy for T-shaped esophageal cancer.

Radiat Oncol 2021 Aug 19;16(1):158. Epub 2021 Aug 19.

Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, No. 241 West Huaihai Road, Xuhui District, Shanghai, 200030, China.

Background: To evaluate the dosimetric and biological benefits of the fixed-jaw (FJ) intensity-modulated radiation therapy (IMRT) technique for patients with T-shaped esophageal cancer.

Methods: FJ IMRT plans were generated for thirty-five patients and compared with jaw tracking (JT) IMRT, static jaw (SJ) IMRT and JT volumetric modulated arc therapy (VMAT). Dosimetric parameters, tumor control probability (TCP) and normal tissue complication probability (NTCP), monitor units (MUs), delivery time and gamma passing rate, as a measure of dosimetric verification, were compared. The correlation between the length of PTV-C below the upper boundary of lung tissue (PTV-C) and dosimetric parameters and NTCP of the lung tissue were analyzed.

Results: The homogeneity and conformity of the target in the four plans were basically equivalent. When compared to the JT IMRT and SJ IMRT plans, FJ IMRT plan led to a statistically significant improvement in the NTCP and low-middle dosimetric parameters of the lung, and the improvement had a moderately positive correlation with the length of PTV-C, with a correlation coefficient ranging from 0.523 to 0.797; the FJ IMRT plan exhibited better lung sparing in low-dose volumes than the JT VMAT plan. The FJ IMRT plan had similar MUs (888 ± 99) and delivery times (516.1 ± 54.7 s) as the JT IMRT plan (937 ± 194, 522 ± 5.6 s) but higher than SJ IMRT (713 ± 137, 488.8 ± 45.2 s) and JT VMAT plan (517 ± 59, 263.7 ± 43.3 s).

Conclusions: The FJ IMRT technique is superior in reducing the low-dose volumes of lung tissues for patients with T-shaped esophageal cancer.
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http://dx.doi.org/10.1186/s13014-021-01882-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8375041PMC
August 2021

Geometric and Dosimetric Changes in Tumor and Lung Tissue During Radiotherapy for Lung Cancer With Atelectasis.

Front Oncol 2021 22;11:690278. Epub 2021 Jul 22.

Shanghai Chest Hospital, Shanghai Jiaotong University, Shanghai, China.

Background And Purpose: This article retrospectively characterized the geometric and dosimetric changes in target and normal tissues during radiotherapy for lung cancer patients with atelectasis.

Materials And Methods: A total of 270 cone beam computed tomography (CBCT) scans of 18 lung patients with atelectasis were collected. The degree and time of resolution or expansion of the atelectasis were recorded. The geometric, dosimetric, and biological changes in the target and lung tissue were also quantified.

Results: There were two patients with expansion, four patients with complete regression, six patients with partial regression, and six patients with no change. The time of resolution or expansion varied. The tumor volume increased by 3.8% in the first seven fractions, then decreased from the 9th fraction, and by 33.4% at the last CBCT. In the LR direction, the average center of mass (COM), boundaries of the tumors gradually shifted mediastinally. In the AP direction, the COM of the tumors was shifted slightly in the posterior direction and then gradually shifted to the anterior direction; the boundaries of the tumors all moved mediastinally. In the SI direction, the COM of the tumors on the right side of the body was substantially shifted toward the head direction. The boundaries of the tumors varied greatly. D, D, D, V, V, and TCP of the PTV were reduced during radiotherapy and were reduced to their lowest values during the last two fractions. The volume of the ipsilateral lung tended to increase gradually. The V, V, V, V, V, and NTCP of the total lung gradually increased with the fraction.

Conclusions: For most patients, regression of the atelectasis occurred, and the volume of the ipsilateral lung tended to increase while the tumor volume decreased, and the COM and boundary of the tumors shifted toward mediastinum, which caused an insufficient dose to the target and an overdose to the lungs. Regression or expansion may occur for any fraction, and it is therefore recommended that CBCT be performed at least every other day.
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http://dx.doi.org/10.3389/fonc.2021.690278DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8339992PMC
July 2021

Virtual Patient-Specific Quality Assurance of IMRT Using UNet++: Classification, Gamma Passing Rates Prediction, and Dose Difference Prediction.

Front Oncol 2021 20;11:700343. Epub 2021 Jul 20.

Shanghai Chest Hospital, Shanghai Jiaotong University, Shanghai, China.

The dose verification in radiotherapy quality assurance (QA) is time-consuming and places a heavy workload on medical physicists. To provide a clinical tool to perform patient specific QA accurately, the UNet++ is investigated to classify failed or pass fields (the GPR lower than 85% is considered "failed" while the GPR higher than 85% is considered "pass"), predict gamma passing rates (GPR) for different gamma criteria, and predict dose difference from virtual patient-specific quality assurance in radiotherapy. UNet++ was trained and validated with 473 fields and tested with 95 fields. All plans used Portal Dosimetry for dose verification pre-treatment. Planar dose distribution of each field was used as the input for UNet++, with QA classification results, gamma passing rates of different gamma criteria, and dose difference were used as the output. In the test set, the accuracy of the classification model was 95.79%. The mean absolute error (MAE) were 0.82, 0.88, 2.11, 2.52, and the root mean squared error (RMSE) were 1.38, 1.57, 3.33, 3.72 for 3%/3mm, 3%/2 mm, 2%/3 mm, 2%/2 mm, respectively. The trend and position of the predicted dose difference were consistent with the measured dose difference. In conclusion, the Virtual QA based on UNet++ can be used to classify the field passed or not, predict gamma pass rate for different gamma criteria, and predict dose difference. The results show that UNet++ based Virtual QA is promising in quality assurance for radiotherapy.
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http://dx.doi.org/10.3389/fonc.2021.700343DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8330420PMC
July 2021

A novel lung-avoidance planning strategy based on 4DCT ventilation imaging and CT density characteristics for stage III non-small-cell lung cancer patients.

Strahlenther Onkol 2021 Aug 5. Epub 2021 Aug 5.

Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, NO.241 West Huaihai Road, Xuhui District, 20030, Shanghai, China.

Background: Functional planning based merely on 4DCT ventilation imaging has limitations. In this study, we proposed a radiotherapy planning strategy based on 4DCT ventilation imaging and CT density characteristics.

Materials And Methods: For 20 stage III non-small-cell lung cancer (NSCLC) patients, clinical plans and lung-avoidance plans were generated. Through deformable image registration (DIR) and quantitative image analysis, a 4DCT ventilation map was calculated. High-, medium-, and low-ventilation regions of the lung were defined based on the ventilation value. In addition, the total lung was also divided into high-, medium-, and low-density areas according to the HU threshold. The lung-avoidance plan aimed to reduce the dose to functional and high-density lungs while meeting standard target and critical structure constraints. Standard and dose-function metrics were compared between the clinical and lung-avoidance plans.

Results: Lung avoidance plans led to significant reductions in high-function and high-density lung doses, without significantly increasing other organ at risk (OAR) doses, but at the expense of a significantly degraded homogeneity index (HI) and conformity index (CI; p < 0.05) of the planning target volume (PTV) and a slight increase in monitor units (MU) as well as in the number of segments (p > 0.05). Compared with the clinical plan, the mean lung dose (MLD) in the high-function and high-density areas was reduced by 0.59 Gy and 0.57 Gy, respectively.

Conclusion: A lung-avoidance plan based on 4DCT ventilation imaging and CT density characteristics is feasible and implementable, with potential clinical benefits. Clinical trials will be crucial to show the clinical relevance of this lung-avoidance planning strategy.
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http://dx.doi.org/10.1007/s00066-021-01821-1DOI Listing
August 2021

Automatic segmentation of lung tumors on CT images based on a 2D & 3D hybrid convolutional neural network.

Br J Radiol 2021 Oct 4;94(1126):20210038. Epub 2021 Aug 4.

Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.

Objective: A stable and accurate automatic tumor delineation method has been developed to facilitate the intelligent design of lung cancer radiotherapy process. The purpose of this paper is to introduce an automatic tumor segmentation network for lung cancer on CT images based on deep learning.

Methods: In this paper, a hybrid convolution neural network (CNN) combining 2D CNN and 3D CNN was implemented for the automatic lung tumor delineation using CT images. 3D CNN used V-Net model for the extraction of tumor context information from CT sequence images. 2D CNN used an encoder-decoder structure based on dense connection scheme, which could expand information flow and promote feature propagation. Next, 2D features and 3D features were fused through a hybrid module. Meanwhile, the hybrid CNN was compared with the individual 3D CNN and 2D CNN, and three evaluation metrics, Dice, Jaccard and Hausdorff distance (HD), were used for quantitative evaluation. The relationship between the segmentation performance of hybrid network and the GTV volume size was also explored.

Results: The newly introduced hybrid CNN was trained and tested on a dataset of 260 cases, and could achieve a median value of 0.73, with mean and stand deviation of 0.72 ± 0.10 for the Dice metric, 0.58 ± 0.13 and 21.73 ± 13.30 mm for the Jaccard and HD metrics, respectively. The hybrid network significantly outperformed the individual 3D CNN and 2D CNN in the three examined evaluation metrics ( < 0.001). A larger GTV present a higher value for the Dice metric, but its delineation at the tumor boundary is unstable.

Conclusions: The implemented hybrid CNN was able to achieve good lung tumor segmentation performance on CT images.

Advances In Knowledge: The hybrid CNN has valuable prospect with the ability to segment lung tumor.
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http://dx.doi.org/10.1259/bjr.20210038DOI Listing
October 2021

Regression models for predicting physical and EQD plan parameters of two methods of hybrid planning for stage III NSCLC.

Radiat Oncol 2021 Jun 27;16(1):119. Epub 2021 Jun 27.

Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiaotong University, Shanghai, China.

Background/purpose: To establish regression models of physical and equivalent dose in 2 Gy per fraction (EQD) plan parameters of two kinds of hybrid planning for stage III NSCLC.

Methods: Two kinds of hybrid plans named conventional fraction radiotherapy & stereotactic body radiotherapy (C&S) and conventional fraction radiotherapy & simultaneous integrated boost (C&SIB) were retrospectively made for 20 patients with stage III NSCLC. Prescription dose of C&S plans was 2 Gy × 30f for planning target volume of lymph node (PTV) and 12.5 Gy × 4f for planning target volume of primary tumor (PTV), while prescription dose of C&SIB plans was 2 Gy × 26f for PTV and sequential 2 Gy × 4f for PTV combined with 12.5 Gy × 4f for PTV. Regression models of physical and EQD plan parameters were established based on anatomical geometry features for two kinds of hybrid plans. The features were mainly characterized by volume ratio, min distance and overlapping slices thickness of two structures. The possibilities of regression models of EQD plan parameters were verified by spearman's correlation coefficients between physical and EQD plan parameters, and the influence on the consistence of fitting goodness between physical and EQD models was investigated by the correlations between physical and EQD plan parameters. Finally, physical and EQD models predictions were compared with plan parameters for two new patients.

Results: Physical and EQD plan parameters of PTV CI have shown strong positive correlations with PTV volume and min distance, and strong negative correlations with PTV volume for two kinds of hybrid plans. PTV CI is not only correlated with above three geometry features, but also negatively correlated with overlapping slices thickness. When neck lymph node metastasis was excluded from PTV volume, physical and EQD total lung V showed a high linear correlation with corrected volume ratio Meanwhile, physical total lung mean dose (MLD) had a high linear correlation with corrected volume ratio, while EQD total lung MLD was not only affected by corrected volume ratio but also volume ratio Heart D, D and mean dose (MHD) would be more susceptible to overlapping structure. Min distance may be an important feature for predicting EQD esophageal max dose for hybrid plans. It's feasible for regression models of EQD plan parameters, and the consistence of the fitting goodness of physical and EQD models had a positive correlation with spearman's correlation coefficients between physical and EQD plan parameters. For total lung V, ipsilateral lung V, and ipsilateral lung MLD, the models could predict that C&SIB plans were higher than C&S plans for two new patients.

Conclusion: The regression models of physical and EQD plan parameters were established with at least moderate fitting goodness in this work, and the models have a potential to predict physical and EQD plan parameters for two kinds of hybrid planning.
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http://dx.doi.org/10.1186/s13014-021-01848-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8237456PMC
June 2021

A novel specific grading standard study of auto-segmentation of organs at risk in thorax: subjective-objective-combined grading standard.

Biomed Eng Online 2021 Jun 3;20(1):54. Epub 2021 Jun 3.

Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, 200030, China.

Background: To develop a novel subjective-objective-combined (SOC) grading standard for auto-segmentation for each organ at risk (OAR) in the thorax.

Methods: A radiation oncologist manually delineated 13 thoracic OARs from computed tomography (CT) images of 40 patients. OAR auto-segmentation accuracy was graded by five geometric objective indexes, including the Dice similarity coefficient (DSC), the difference of the Euclidean distance between centers of mass (ΔCMD), the difference of volume (ΔV), maximum Hausdorff distance (MHD), and average Hausdorff distance (AHD). The grading results were compared with those of the corresponding geometric indexes obtained by geometric objective methods in the other two centers. OAR auto-segmentation accuracy was also graded by our subjective evaluation standard. These grading results were compared with those of DSC. Based on the subjective evaluation standard and the five geometric indexes, the correspondence between the subjective evaluation level and the geometric index range was established for each OAR.

Results: For ΔCMD, ΔV, and MHD, the grading results of the geometric objective evaluation methods at our center and the other two centers were inconsistent. For DSC and AHD, the grading results of three centers were consistent. Seven OARs' grading results in the subjective evaluation standard were inconsistent with those of DSC. Six OARs' grading results in the subjective evaluation standard were consistent with those of DSC. Finally, we proposed a new evaluation method that combined the subjective evaluation level of those OARs with the range of corresponding DSC to determine the grading standard. If the DSC ranges between the adjacent levels did not overlap, the DSC range was used as the grading standard. Otherwise, the mean value of DSC was used as the grading standard.

Conclusions: A novel OAR-specific SOC grading standard in thorax was developed. The SOC grading standard provides a possible alternative for evaluation of the auto-segmentation accuracy for thoracic OARs.
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http://dx.doi.org/10.1186/s12938-021-00890-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8173789PMC
June 2021

PET/CT in a patient with cardiac paraganglioma.

Int J Cardiovasc Imaging 2021 Apr 20;37(4):1473-1477. Epub 2020 Nov 20.

Department of Ultrasound, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Shandong University, No. 324 Jingwu Road, Jinan, 250021, People's Republic of China.

A 22-year-old female with SDHB-positive who presented with palpitation and hypertension after adrenalectomy was performed F-FDG PET/CT to detect the primary ectopic pheochromocytoma (PCC) and rule out metastasis. PET/CT is useful for detecting and localizing the primary ectopic PCC.
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http://dx.doi.org/10.1007/s10554-020-02101-2DOI Listing
April 2021

Impact of Physico-Chemical Heterogeneity on Arsenic Sorption and Reactive Transport under Water Extraction.

Environ Sci Technol 2020 12 10;54(23):14974-14983. Epub 2020 Nov 10.

School of Environmental Science & Engineering, Southern University of Science and Technology, 518055 Shenzhen, Guangdong, China.

Heterogeneity in physical and chemical properties is a common characteristic in a subsurface environment. This study investigated the effect of physico-chemical heterogeneity on arsenic (As) sorption and reactive transport under water extraction in a layered system with preferential flow paths. A flume experiment was performed to derive the spatio-temporal data of As reactive transport. The results indicated that the heterogeneous system significantly accelerated downward (vertical direction) As migration as a coupled effect of physical and chemical heterogeneity that led to fast As transport with low As sorption along the preferential flow paths. The results also indicated that such a heterogeneity effect was driven by water extraction that enhanced the downward groundwater flow along the preferential flow paths. Numerical simulations were performed by matching the experimental results to provide insights into the dominant processes controlling the As migration in the heterogeneous systems. The simulation results highlighted the importance of the kinetic oxidation of mineral-bonded Fe(II) to Fe(III) in the clay matrix that dynamically increased As sorption affinity and retarded As reactive transport. A coupled model of reactive transport along the preferential flow paths, sorption-retarded diffusion from the preferential flow paths into the clay matrixes, and reactions that change sorption affinity in the matrix was required to describe the As reactive transport systems with physico-chemical heterogeneities. The results have strong implications for understanding and modeling As downward migration from shallow to deep aquifers under groundwater pumping conditions in field systems with inherent heterogeneity.
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http://dx.doi.org/10.1021/acs.est.0c03587DOI Listing
December 2020

Effect of MU-weighted multi-leaf collimator position error on dose distribution of SBRT radiotherapy in peripheral non-small cell lung cancer.

J Appl Clin Med Phys 2020 Dec 31;21(12):74-83. Epub 2020 Oct 31.

Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.

Purpose: Position accuracy of the multi-leaf collimator (MLC) is essential in stereotactic body radiotherapy (SBRT). This study is aimed to investigate the dosimetric impacts of the MU-weighted MLC positioning uncertainties of SBRT for patients with early stage peripheral non-small cell lung cancer (NSCLC).

Methods: Three types of MLC position error were simulated: Type 1, random error; Type 2, system shift, in which both MLC banks shifted to the left or right direction; and Type 3, in which both MLC banks moved with same magnitudes in the opposite directions. Two baseline plans were generated: an automatic plan (AP) and a manually optimized plan (MP). Multi-leaf collimator position errors were introduced to generate simulated plans with the preset MLC leaf position errors, which were then reimported into the Pinnacle system to generate simulated plans, respectively. The dosimetric parameters (CI, nCI, GI, etc.) and gEUD values of PTV and OARs were calculated. Linear regression between MU-weighted/unweighted MLC position error and gEUD was performed to obtain dose sensitivity.

Results: The dose sensitivities of the PTVs were -4.93, -38.94, -41.70, -55.55, and 30.33 Gy/mm for random, left shift, right shift, system close, and system open MLC errors, respectively. There were significant differences between the MU-weighted and the unweighted dose sensitivity, which was -38.94 Gy/mm vs -3.42 Gy/mm (left shift), -41.70 Gy/mm vs -3.56 Gy/mm (right shift), -55.55 Gy/mm vs -4.84 Gy/mm (system close), and 30.33 vs 2.64 Gy/mm (system open). For the system open/close MLC errors, as the PTV volume became larger, the dose sensitivity decreased. APs provided smaller dose sensitivity for the system shift and system close MLC errors compared to the conventional MPs.

Conclusions: There was significant difference in dose sensitivity between MU-weighted and unweighted MLC position error of SBRT radiotherapy in peripheral NSCLC. MU is suggested to be included in the dosimetric evaluation of the MLC misalignments, since it is much closer to clinical radiotherapy.
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http://dx.doi.org/10.1002/acm2.13061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7769390PMC
December 2020

Comparison of diffusion-weighted imaging mono-exponential mode with diffusion kurtosis imaging for predicting pathological grades of clear cell renal cell carcinoma.

Eur J Radiol 2020 Sep 26;130:109195. Epub 2020 Jul 26.

Department of Radiology, Zibo Central Hospital, Zibo, Shandong, China; Zibo Key Laboratory of Precision Neuroimaging, China. Electronic address:

Purpose: To evaluate the role of diffusion kurtosis imaging (DKI) in the characterization of clear cell renal cell carcinoma (ccRCC) compared with standard diffusion-weighted imaging (DWI).

Methods: 89 patients with histologically proven ccRCC were evaluated by DKI and DWI on a 3-T scanner. All ccRCCs were classified as grade 1-4 according to the Fuhrman classification system. The apparent diffusion coefficient (ADC), fractional anisotropy (FA), mean diffusivity (MD), mean kurtosis (MK), axial kurtosis (Ka) and radial kurtosis (Kr) values were recorded. The differences in DWI and DKI parameters were evaluated by independent-sample t test and a receiver operating characteristic (ROC) analysis was performed. The DeLong test was performed to compare the ROCs.

Results: Compared to normal renal parenchyma, ADC and MD values of ccRCC decreased and MK, Ka, and Kr values increased (p < 0.05). ADC and MD values of ccRCC decreased with the increase in pathological grade, while MK, Ka, and Kr values were increased (p < 0.05). ADC could discriminate G1 vs G3, G1 vs G4, G2 vs G3, G2 vs G4, and G3 vs G4 (p < 0.05) except for G1 vs G2 (p > 0.05). Ka and Kr could discriminate G1 vs G2, G1 vs G3, G1 vs G4, G2 vs G4, and G3 vs G4 (p < 0.05) except for G2 vs G3 (p > 0.05). MD and MK could discriminate G1 vs G2, G1 vs G3, G1 vs G4, G2 vs G3, G2 vs G4, and G3 vs G4 (p < 0.05). The AUC of MK was the highest. The DeLong test showed that there were significant differences regarding ROCs between ADC/MK, ADC/Ka, ADC/Kr in grading G1/G2, and ADC/MK, MK/Ka in grading G3/G4 (p < 0.05).

Conclusion: DKI was superior compared to the mono-exponential mode of DWI in grading ccRCC.
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http://dx.doi.org/10.1016/j.ejrad.2020.109195DOI Listing
September 2020

On the optimal number of dose-limiting shells in the SBRT auto-planning design for peripheral lung cancer.

J Appl Clin Med Phys 2020 Sep 23;21(9):134-142. Epub 2020 Jul 23.

Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA.

Purpose: The number of dose-limiting shells in the optimization process is one of the key factors determining the quality of stereotactic body radiotherapy (SBRT) auto-planning in the Pinnacle treatment planning system (TPS). This study attempted to derive the optimal number of shells by evaluating the auto-plans designed with different number of shells for peripheral lung cancer patients treated with SBRT.

Methods: Identical treatment technique, optimization process, constraints, and dose calculation algorithm in the Pinnacle TPS were retrospectively applied to 50 peripheral lung cancer patients who underwent SBRT in our center. For each of the patients, auto-plans were optimized based on two shells, three shells, four shells, five shells, six shells, seven shells, eight shells, respectively. The optimal number of shells for the SBRT auto-planning was derived through the evaluations and comparisons of various dosimetric parameters of planning target volume (PTV) and organs at risk (OARs), monitor units (MU), and optimization time of the plans.

Results: The conformity index (CI) and the gradient index (GI) of PTV, the maximum dose outside the 2 cm of PTV (D ), D of spinal cord (SC ), the percentage of volume of total lung excluding ITV receiving 20 Gy (V20) and 10 Gy (V10), and the mean lung dose (MLD) were improved when the number of shell increased, but the improvement became not significant as the number of shell reached six. The monitor units (MUs) varied little among different plans where no statistical differences were found. However, as the number of shell increased, the auto-plan optimization time increased significantly.

Conclusions: It appears that for peripheral lung SBRT plan using six shells can yield satisfactory plan quality with acceptable beam MUs and optimization time in the Pinnacle TPS.
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http://dx.doi.org/10.1002/acm2.12983DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7497906PMC
September 2020

Image quality and radiation dose of different scanning protocols in DSCT cardiothoracic angiography for children with tetralogy of fallot.

Int J Cardiovasc Imaging 2020 Sep 17;36(9):1791-1799. Epub 2020 May 17.

Department of Medical Imaging, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, 210002, People's Republic of China.

The aim of this study was to investigate the image quality and radiation dose of different scanning protocols in dual-source CT cardiothoracic angiography for children with tetralogy of Fallot (TOF). Seventy-five consecutive children with known or suspected TOF were enrolled to undergo prospective ECG-triggering sequential dual-source CT (DSCT) cardiothoracic angiography. According to the scanning protocols, these patients were randomly divided into 3 groups: fixed delay time (FDT, n = 25, group A), automatic bolus-tracking (ABT, n = 25, group B) and manual bolus-tracking (MBT, n = 25, group C). Subjective and objective image quality were evaluated. The radiation doses were recorded. The image quality scores of group C were significantly higher than those of group A and B. The absolute value of difference (D-value) on CT attenuation between left (CT) and right ventricle (CT) in group C was significantly lower than that in group A and B. The total effective dose of groups A, B and C were 0.39 ± 0.06 mSv, 0.40 ± 0.07 mSv and 0.40 ± 0.08 mSv, respectively. There was no significant difference among 3 groups (P = 0.722). Scanning protocol has significantly impacts on the image quality of cardiovascular structures for TOF patients. Compared with the conventional scanning protocols FDT and ABT, the MBT technique provides high image quality and achieves more homogenous attenuation among different patients with TOF.
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http://dx.doi.org/10.1007/s10554-020-01882-wDOI Listing
September 2020

Dynamic Indicators That Impact the Outcomes of Thoracic Endovascular Aortic Repair in Complicated Type B Aortic Dissection.

J Vasc Interv Radiol 2020 05 22;31(5):760-768.e1. Epub 2020 Jan 22.

Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, Shandong 250021, China. Electronic address:

Purpose: To investigate dynamic variables obtained from retrospective computed tomography angiography for ability to predict thoracic endovascular aortic repair (TEVAR) outcomes in patients with complicated type B aortic dissection (cTBAD).

Materials And Methods: Seventy-nine patients with cTBAD who received TEVAR from March 2009 to June 2018 were retrospectively enrolled. Relative true lumen area (r-TLA) was computed at the level of tracheal bifurcation every 5% of all R-R intervals. Parameters that reflect the state of intimal motion were evaluated, including difference between maximum and minimum r-TLA (D-TLA) and true lumen collapse. The endpoints comprised early (≤ 30 days) and late (> 30 days) outcomes after intervention.

Results: Overall early mortality rate was 13.9% (11/79), and early adverse events rate was 24.1% (19/79). Patients who received TEVAR within 2 days of symptom onset demonstrated the worst outcomes. A longer time of r-TLA < 25% in 1 cardiac cycle (P = .049) and larger D-TLA (P < .001) were correlated to an increased early death. In addition, D-TLA was an independent predictor of early mortality. Area under the curve of D-TLA was 0.849 (95% confidence interval 0.730-0.967) for predicting early mortality and 0.742 (95% CI 0.611-0.873) for predicting early adverse events. Survival and event-free survival rates during follow-up were decreased in the D-TLA > 21.5% group compared with the D-TLA ≤ 21.5% group (all P < .001).

Conclusions: Larger D-TLA is correlated with worse postoperative outcomes and might be a crucial parameter for future risk stratification in patients with cTBAD.
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http://dx.doi.org/10.1016/j.jvir.2019.11.010DOI Listing
May 2020

Dynamic Imaging Features of Retrospective Cardiac Gating CT Angiography Influence Delayed Adverse Events in Acute Uncomplicated Type B Aortic Dissections.

Cardiovasc Intervent Radiol 2020 Apr 17;43(4):620-629. Epub 2019 Dec 17.

Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, 250021, Shandong, People's Republic of China.

Purpose: To investigate the correlation between dynamic morphological parameters of retrospective cardiac gating CT angiography (CTA) and delayed adverse event (DAE) in uncomplicated type B acute aortic dissection (uTB-AAD) patients.

Materials And Methods: Eighty-seven patients initially diagnosed with uTB-AAD were retrospectively reviewed. Dynamic variables obtained by dose-regulated retrospective CTA were recorded, including the minimum relative true lumen diameter (RTLA), ratio of the minimum to maximum true lumen relative area (r-RTLA), the maximum diameter of the descending aorta, false lumen, and primary entry tear. Outcome analysis comprised incidences of DAE and early mortality within 3 to 14 days since symptom occurring.

Results: Twenty-six patients (29.9%) developed DAE, and two of which (7.7%) died before any interventions. Smaller values of RTLA (P = 0.01) and r-RTLA at the upper thoracic descending aorta (UTDA) (P < 0.001), and r-RTLA at the renal artery level (P = 0.016) demonstrated higher incidences of DAE; maximum diameter of the descending aorta (P < 0.001), the false lumen (P = 0.008), and entry tear size (P = 0.007) were positively associated with the occurrence of DAE. r-RTLA at the UTDA level yielded the highest diagnostic accuracy (82.0%) in detecting DAE at an optimal cutoff value of 61.7% (AUC = 0.839). Performance of dynamic characteristics was superior to static features obtained from single-phase image in the detection of DAE (P < 0.001).

Conclusion: Dynamic morphological features of retrospective cardiac gating CTA might aid in identifying a high risk of DAE in uTB-AAD patients and guiding early targeted interventions.
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http://dx.doi.org/10.1007/s00270-019-02395-3DOI Listing
April 2020

Anthropogenic influences on dissolved organic matter transport in high arsenic groundwater: Insights from stable carbon isotope analysis and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry.

Sci Total Environ 2020 Mar 21;708:135162. Epub 2019 Nov 21.

School of Environmental Studies, China University of Geosciences, Wuhan 430074, China.

In East and Southeast Asia, the health of over 100 million people is threatened by the consumption of groundwater containing high concentrations of arsenic (>10 μg L), which is released from sediments through reductive dissolution of arsenic-bearing iron/manganese oxides. Dissolved organic matter (DOM) is known to play a crucial role in the process of arsenic mobilization in shallow aquifers, and its availability and reactivity are key factors controlling the variation of arsenic concentrations in groundwater. However, it is unclear how human activities influence the transport of DOM and how the transportation affects the DOM molecular properties in high arsenic groundwater. This study provides insights on the sources and molecular compositions of DOM in groundwater from the Jianghan Plain, central China, a newly discovered area with seasonal fluctuations in arsenic concentrations in shallow groundwater. Monitoring of water levels and stable carbon isotope compositions in groundwater from different depths and canal water over a year indicated that terrestrial DOM was the dominant source, accounting for 54.2%-85.5% of groundwater DOM. Electrospray ionization combined with ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry revealed that canal water infiltration transferred aliphatic, tannin-like and leached aromatic DOM from sediments into groundwater. Therefore, groundwater recharge through irrigation using canal water not only inputs terrestrial DOM, but also accelerates the release of sedimentary DOM. Furthermore, carboxylic-rich alicyclic molecule (CRAM)-like DOM that is derived from biomolecules has the highest proportion (60.1%-65.5%) among the identified DOM structures. And, it might be reused in biochemical processes during arsenic mobilization, suggesting a third source of groundwater DOM in addition to canal water and sediments. The findings in this study advance the understanding on transport processes and molecular properties of DOM in high arsenic groundwater under extensive anthropogenic influences.
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http://dx.doi.org/10.1016/j.scitotenv.2019.135162DOI Listing
March 2020

Dosimetric comparison and biological evaluation of PET- and CT-based target delineation for LA-NSCLC using auto-planning.

Phys Med 2019 Nov 31;67:77-84. Epub 2019 Oct 31.

Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China. Electronic address:

Using auto-planning, the dosimetric and biological differences between PET- and CT-based target delineation in LA-NSCLC were studied. Twenty-three patients with IIIA-IIIB NSCLC were included in this retrospective study. For each patient, two AP plans (Plan_PET, Plan_CT) were generated based on PET- and CT-based gross tumor volume (GTV, GTV). The volume, boundary and center of mass (COM) of GTVPET and GTVCT were compared. Dosimetric indicators such as mean lung dose (MLD) and so on were evaluated. Tumor control probability (TCP) of GTVPET and GTVCT and normal tissue complication probability (NTCP) of total lung and heart were calculated. A paired-samples t-test was used to check for significant differences (p < 0.05) between dataset. Volume of GTVPET was significantly smaller than that of GTVCT. Under the premise that GTVPET met the clinical requirements in Plan_PET, GTVCT couldn't satisfy the requirements. GTVCT met the clinical requirements in Plan_CT, and four cases of GTVPET could not satisfy the requirements. Compared with Plan_CT, Plan_PET significantly reduced MLD, V5, V10, V13, V15, V20, V30 and V40 of total lung, and MHD, V30 and V40 of heart, and MUs. No significant difference was observed with respect to Dmax of spinal cord. TCP of GTVPET in Plan_PET was significantly higher than that of GTVCT. NTCP of total lung in Plan_PET was significantly lower than that in Plan_CT. There were differences in volume, boundary, and COM of targets based on the two delineation methods. These led to differences in dosimetric and biological indicators. For LA-NSCLC, the way that most hospitals only use CT to delineate the target should be careful consideration.
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http://dx.doi.org/10.1016/j.ejmp.2019.09.080DOI Listing
November 2019

Watershed-scale distributions of heavy metals in the hyporheic zones of a heavily polluted Maozhou River watershed, southern China.

Chemosphere 2020 Jan 5;239:124773. Epub 2019 Sep 5.

State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China; Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China. Electronic address:

Hyporheic zone (HZ) sediments in river systems are often contaminated with heavy metals as a legacy of natural processes and anthropogenic activities. The geochemical behaviors of heavy metals in the HZ sediments at the laboratory scale have been extensively studied. However, the watershed-scale distributions of heavy metals in the HZ sediments and the processes controlling their distributions have not been well studied. Here, we report a watershed-scale study of heavy metals (i.e., Cr, Ni, Cu, Zn, Cd, and Pb) distributions in the HZ of the Maozhou River watershed, a heavily polluted area within the Pearl River Delta, southern China. Statistical analysis revealed that the spatial distribution of studied heavy metal concentrations was highly correlated with that of the sediment-associated sulfide at the watershed-scale. Metal extraction analysis and double-spherical aberration-corrected scanning transmission electron microscope imaging (Cs-STEM) further confirmed the strong association of heavy metals with sulfur. These observations demonstrated that the formation of metals-sulfide precipitates was the key process controlling the watershed-scale distributions of heavy metals (especially for Cr, Ni and Zn) in the HZ sediments. Additionally, high permeability of the HZ sediments may prevent Ni, Zn, Cd and Pb accumulation in sediments. Specially, Cu distribution was mainly affected by organic-Cu complexation. In the estuary area, salinity input likely affected the distributions of Ni, Zn and Cd through cation exchange processes. The findings improved our understanding of the distributions of heavy metals and the processes controlling their distributions at the watershed-scale, and have implications for remediating and managing contaminated HZ sediments.
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http://dx.doi.org/10.1016/j.chemosphere.2019.124773DOI Listing
January 2020

Elucidating the Role of Sulfide on the Stability of Ferrihydrite Colloids under Anoxic Conditions.

Environ Sci Technol 2019 04 25;53(8):4173-4184. Epub 2019 Mar 25.

Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering , Southern University of Science and Technology , Shenzhen , 518055 , P. R. China.

While the reaction mechanisms between ferrihydrite and sulfide are well-documented, the role of redox reactions on the particle-particle stability of ferrihydrite colloids is largely overlooked. Such reactions are critical for a number of (bio)geochemical processes governing ferrihydrite-based colloid processing and their associated role in nutrient and contaminant subsurface dynamics. Taking a fundamental colloid chemistry approach, along with a complementary suite of characterization techniques, here, we explore the stability mechanisms of ferrihydrite colloids over a wide range of environmentally relevant sulfide concentrations at pH 6.0. Results show that sulfide lowered the stability of both ferrihydrite colloids in a concentration-dependent fashion. At lower sulfide concentrations (15.6-62.5 μM), ferrihydrite colloids are apparently stable, but their critical coagulation concentration (CCC) in NaCl linearly decreases with increasing sulfide concentration. This is attributed to the formation of negatively charged elemental sulfur (S(0)) nanoparticles on the surfaces of positively charged ferrihydrite, intensifying the electrostatic attractions between oppositely charged regions on adjacent ferrihydrite surfaces. Further increasing sulfide concentration generates more S(0) attaching to the ferrihydrite surface. This results in effective surface charge neutralization and then subsequent charge reversal, leading to extensive aggregation of ferrihydrite (core) colloids. Interestingly, for the ferrihydrite colloids with higher hydrodynamic diameter, aggregation rates linearly decreases with increasing sulfide concentration from 156.3 to 312.5 μM, which is likely due to the formation of substantial amounts of negatively charged S(0) and FeS. Findings highlight the significance of sulfidation products in controlling the stability of ferrihydrite colloids in sulfidic environments.
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http://dx.doi.org/10.1021/acs.est.8b05694DOI Listing
April 2019

Impact of the Intima Dynamic Motion in Type B Acute Aortic Dissection on Renal Injury: Quantificationally Assessed by Dose-Regulated Retrospective ECG-Gated Dual-Source CT Angiography.

Acad Radiol 2019 10 15;26(10):1320-1327. Epub 2019 Jan 15.

Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, Shandong 250021, PR China. Electronic address:

Background: Little is known about the influence of intima dynamic motion on organ ischemia and related outcomes. The purpose of this study is to quantitatively evaluate intima oscillation by CT angiography (CTA), determine its impact on acute kidney injury (AKI) in patients with type B acute aortic dissection (TB-AAD) before thoracic endovascular aortic repair (TEVAR), and further analyze its association with early adverse events postoperatively.

Methods: Totally, 108 patients with TB-AAD who underwent retrospective ECG-gated CTA and received TEVAR were enrolled. Patients were divided into AKI and non-AKI groups. Area of the true lumen (TLA) was computed at R-R intervals at the upper level of kidney vessel origin every 5% step from 0% to 95%. Additionally, other morphologic parameters that have been identified as risk predictors for adverse events in uncomplicated TB-AAD were evaluated.

Results: Forty-three (39.8%) patients were sorted into the AKI group. Patients with AKI exhibited a larger value for the relative change of TLA (C-TLA) than patients in the non-AKI group (p < 0.001), as well as a larger maximum diameter of the descending aorta (p = 0.023) and the primary entry tear (p = 0.012). C-TLA and elevated systolic blood pressure were independent predictors of AKI. Patients with C-TLA ≥ 42.6% were associated with a high incidence of renal ischemia before TEVAR and early adverse events postoperatively (all p < 0.001).

Conclusion: Intima dynamic motion, as quantitatively evaluated by CTA, has a significant influence on renal injury before and after the aortic intervention, as well as other adverse events, which might guide clinical therapy in high-risk patients.
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http://dx.doi.org/10.1016/j.acra.2018.12.018DOI Listing
October 2019

Image quality and radiation dose of two prospective ECG-triggered protocols using 128-slice dual-source CT angiography in infants with congenital heart disease.

Int J Cardiovasc Imaging 2019 May 17;35(5):937-945. Epub 2019 Jan 17.

Department of Radiology, Shandong Provincial Hospital, Key Laboratory of Diagnosis and Treatment of Cardio-cerebral Vascular Diseases, Shandong University, #324, Jingwu Road, Jinan, 250021, Shandong, People's Republic of China.

This study aims to investigate the image quality and radiation dose of prospective ECG-triggered 128-slice dual-source CT (DSCT) angiography in the delineation of coronary arteries in infants with congenital heart disease (CHD). Sixty-three infants with CHD were randomly assigned into two groups: prospective ECG-triggered sequential protocol (group 1) and high-pitch spiral protocol (group 2). Patients were selected to the protocols randomly. A five-point scoring system was applied to study the capability of detecting coronary arteries. A score of < 3 represents non-diagnostic. Effective radiation dose (ED) was calculated. The visualized rate for original, proximal, middle and distal segments of the coronary arteries was 98%, 95%, 94% and 83%, respectively in group 1, 93%, 82%, 53% and 34%, respectively in group 2. There were no significant demographic differences in the identification rate between the two groups as to the original and most of the proximal segments. Significant demographic differences were found in middle and distal segments (p < 0.05). The mean ED of the high pitch group and the sequential group was 0.33 ± 0.11 mSv and 0.63 ± 0.16 mSv, respectively. Both the prospective ECG-gated high-pitch mode and the sequential mode for 128-slice DSCT allow satisfactory delineation of original and most of the proximal segments of coronary arteries in infants with CHD. However, an ECG-gated sequential mode is recommended when detailed anatomic assessment of the whole coronary arteries are needed since the ECG-gated high-pitch mode is limited in the delineation of middle and distal segments of the coronary arteries.
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http://dx.doi.org/10.1007/s10554-018-01526-0DOI Listing
May 2019

An efficient optic cup segmentation method decreasing the influences of blood vessels.

Biomed Eng Online 2018 Sep 26;17(1):130. Epub 2018 Sep 26.

Department of Ophthalmology, Hospital of Beijing University of Technology, Beijing, 100124, China.

Background: Optic cup is an important structure in ophthalmologic diagnosis such as glaucoma. Automatic optic cup segmentation is also a key issue in computer aided diagnosis based on digital fundus image. However, current methods didn't effectively solve the problem of edge blurring caused by blood vessels around the optic cup.

Methods: In this study, an improved Bertalmio-Sapiro-Caselles-Ballester (BSCB) model was proposed to eliminate the noising induced by blood vessel. First, morphological operations were performed to get the enhanced green channel image. Then blood vessels were extracted and filled by improved BSCB model. Finally, Local Chart-Vest model was used to segment the optic cup. A total of 94 samples which included 32 glaucoma fundus images and 62 normal fundus images were experimented.

Results: The evaluation parameters of F-score and the boundary distance achieved by the proposed method against the results from experts were 0.7955 ± 0.0724 and 11.42 ± 3.61, respectively. Average vertical optic cup-to-disc ratio values of the normal and glaucoma samples achieved by the proposed method were 0.4369 ± 0.1193 and 0.7156 ± 0.0698, which were also close to those by experts. In addition, 39 glaucoma images from the public dataset RIM-ONE were also used for methodology evaluation.

Conclusions: The results showed that our proposed method could overcome the influence of blood vessels in some degree and was competitive to other current optic cup segmentation algorithms. This novel methodology will be expected to use in clinic in the field of glaucoma early detection.
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http://dx.doi.org/10.1186/s12938-018-0560-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6158914PMC
September 2018

Profiling microbial communities in a watershed undergoing intensive anthropogenic activities.

Sci Total Environ 2019 Jan 7;647:1137-1147. Epub 2018 Aug 7.

School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China. Electronic address:

In lotic ecosystems highly susceptible to anthropogenic activities, the influences of environmental variables on microbial communities and their functions remain poorly understood, despite our rapidly increasing sequencing ability. In this study, we profiled the microbial communities in the hyporheic sediments of a watershed undergoing intensive anthropogenic activities via next-generation sequencing of 16S rRNA V4-V5 hypervariable regions on Illumina MiSeq platform. Tidal impacts on microbial communities were investigated via co-occurrence networks. In addition, the influences of physicochemical variables including salinity, and the concentrations of nutrients, organic matter and heavy metals on the microbial communities were explored via canonical correspondence analyses. The sediment samples were collected from 19 sites covering the whole main river stem of the target watershed (n = 19; Maozhou river watershed, Shenzhen, China). The samples were sub-divided in the field for microbiological analyses and measurements of physicochemical variables. The results indicated that core microbiome was associated with archaea methanogens and bacteria members from Proteobacteria, Chloroflexi, Bacteroidetes, Acidobacteria, Synergistetes and Firmicutes, among which, gram-negative and anaerobic bacteria genera contributing to the cycling of carbon, nitrogen and sulfur were predominant. Site-specific microbiomes were revealed that may serve as indicators of local environmental conditions (e.g., members affiliated to Oceanospirillales were abundant at sites with salt intrusion). Distinct microbial co-occurrence networks were identified for non-tidal, inter-tidal and tidal sites. Major environmental factors influencing microbial community composition included the concentrations of nitrate and bicarbonate in river water, pore water concentrations of sulfate, dissolved organic carbon and electrical conductivity, as well as manganese concentrations associated with the solid sediment. Collectively, the results of this study provide fundamental insights into the influence of environmental perturbations on microbial community composition in a lotic system, which may aid in the design of effective remediation and/or restoration strategies in the target watershed and beyond.
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http://dx.doi.org/10.1016/j.scitotenv.2018.08.103DOI Listing
January 2019

Experimental constraints on redox-induced arsenic release and retention from aquifer sediments in the central Yangtze River Basin.

Sci Total Environ 2019 Feb 17;649:629-639. Epub 2018 Aug 17.

Earth System Science Dept., Stanford University, Stanford, CA 94305, United States. Electronic address:

The consumption of arsenic (As) contaminated groundwater affects the health of almost 20 million people in China. Unlike the preponderance of observations within the deltas of South and Southeast Asia, groundwater As concentrations in the central Yangtze River Basin, China, vary by up to an order of magnitude seasonally. In order to decipher the cause of seasonal release and retention of As between sediments and groundwater, we conducted batch sediment incubations under varying (imposed) redox conditions. Incubations were conducted under both N and O gas purges to simulate conditions observed within the field. In all cases, anoxic conditions resulted in As release to solution while As was removed from solution under oxic conditions. These experiments confirm that anoxia is a prerequisite for As mobilization into groundwater from Yangtze River Basin sediments. Alternating redox conditions resulted in Fe minerals dissolution, transformation, crystallization, and precipitation, and subsequent As release and retention in the system. More importantly, aquifer sediments at depths >15 m release As through multiple redox cycles without an exogenous electron donor (carbon source), organic matter in the sediments is sufficiently reactive to support microbial reduction of As(V) and Fe(III). These results provide direct evidence for previously described mechanisms explaining the observed seasonal variation of groundwater As concentrations in the central Yangtze River Basin, where seasonal changes in surface and groundwater levels drive changes in redox conditions and thus As concentrations.
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http://dx.doi.org/10.1016/j.scitotenv.2018.08.205DOI Listing
February 2019

Organic carbon sources and controlling processes on aquifer arsenic cycling in the Jianghan Plain, central China.

Chemosphere 2018 Oct 30;208:773-781. Epub 2018 May 30.

School of Environmental Studies, China University of Geosciences, Wuhan, Hubei 430074, China.

Groundwater arsenic contamination is a common environmental problem that threatens the health of over 100 million people globally. Apparent seasonal fluctuations in groundwater arsenic concentrations have been reported in various locations worldwide, including the Jianghan Plain, central China. This phenomenon has been attributed to shifts in redox conditions induced by seasonal incursions of surface water. However, it is not clear what processes during the incursion lead to changes in the redox conditions and what is the source of the organic carbon driving these processes. Therefore, we conducted a long-term investigation of stable carbon isotopic compositions in surface water and groundwater, as well as long-term monitoring of hydraulic gradients and geochemical compositions at the Jianghan Plain. Results indicated that a series of biogeochemical processes occurred during surface water incursion, including aerobic microbial respiration, nitrate and sulfate reduction. Groundwater arsenic was removed by adsorption on iron oxyhydroxides produced during oxidation of ferrous iron, resulting in dramatic decreases in arsenic concentrations during surface water recharge seasons. These processes were likely driven by organic carbon vertically transported from surface water and released from the surficial aquitard above 15 m. Groundwater pumping may accelerate the vertical infiltration of oxidizing recharge water and drive exogenous organic carbon to depth. Findings of this study advance the understandings of the mechanisms that cause temporal variations in groundwater As and the importance of exogenous organic carbon that may influence the temporal behavior of arsenic in groundwater.
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http://dx.doi.org/10.1016/j.chemosphere.2018.05.188DOI Listing
October 2018

An innovative technique of perventricular device closure of a coronary artery fistula through a left parasternal approach.

Eur Heart J 2017 11;38(42):3177

Ultrasound Department, Shandong Provincial Hospital Affiliated to Shandong University, No. 324, Jingwu Road, Jinan 250021, China.

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http://dx.doi.org/10.1093/eurheartj/ehx357DOI Listing
November 2017

Arsenic speciation in aquifer sediment under varying groundwater regime and redox conditions at Jianghan Plain of Central China.

Sci Total Environ 2017 Dec 27;607-608:992-1000. Epub 2017 Jul 27.

Geological Survey, China University of Geosciences, 430074 Wuhan, China.

At Jianghan Plain of central Yangtze basins where the health of >73, 000 people has been affected by long term intake of high arsenic groundwater, over 100 sediment samples from four boreholes at the field monitoring sites were collected and analyzed to delineate the distribution and speciation of As in the shallow aquifer sediment. Results showed that sediment As concentration is generally dependent on the lithological conditions, with the higher As concentration present in fine particle sediment, especially in the silty sand layers underlying clay or silty clay layers. High As concentration in the sediment mainly occurred in three different depth ranges: <5m, 15-35m, and >35m. Both the groundwater regime and redox conditions played important roles in controlling sediment As speciation. Arsenate (86%) was the dominated As species in the near surface sediment. As the redox turned to be reducing, arsenite (64%) became the dominant species in the underlying clay and silty clay layers. But in the silty sand aquifer near the boundary of unconfined aquifer and confined aquifer, arsenate (85%) became the dominant species again as results of redox potential elevation. In the deep medium to coarse sand aquifers (>35m deep), As-sulfides (49%-63%) were the main species of As. The speciation and reactivity of sediment As strongly controlled the spatial distribution of groundwater As concentration, while seasonal variation in groundwater As concentration and speciation affected the content and speciation of sediment As.
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http://dx.doi.org/10.1016/j.scitotenv.2017.07.011DOI Listing
December 2017
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