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Purpose: To evaluate the relationship between the serum calcitonin gene-related peptide (CGRP) level and severity of coronary stenosis. Methods: A total of 233 eligible patients who underwent coronary angiography were divided into two groups: a control and a coronary heart disease (CHD) group. The angiographic severity of coronary stenosis was evaluated by SYNTAX and Gensini scores. The incidence of major adverse cardiovascular events within two years was collected. Results: A negative correlation between serum CGRP levels and Gensini scores was observed in all patients (r=-0.352, p22) was 0.772 [95% confidence interval (CI): 0.673-0.870, p22 [odds ratio (OR) =5.819, 95% CI: 2.240-15.116; p64) (OR=4.943, 95% CI: 2.020-12.095; p

Background Treatment for radioiodine refractory differentiated thyroid carcinoma (RR-DTC) is challenging. The purpose of this study was to assess the efficacy and safety of ultrasound-guided implantation of radioactive 125I-seed in radioiodine refractory differentiated thyroid carcinoma. Methods Thirty-six cervical metastatic lymph nodes (CMLNs) diagnosed with RR-DTC from 18 patients were enrolled in this retrospective study. US and contrast-enhanced ultrasound (CEUS) examinations were performed before implantation. Follow-up comprised US, CEUS, thyroglobulin (Tg) level and routine hematology at 1–3, 6, 9 and 12 months and every 6 months thereafter. The volumes of the nodules were compared before implantation and at each follow-up point. The volume reduction rate (VRR) of nodules was also recorded. Results The median volume of the nodules was 523 mm3 (148, 2010mm3) initially, which decreased significantly to 53mm3 (0, 286mm3) (P 125I seed images were visible in the US. At the last follow-up visit, the serum Tg level decreased from 57.0 (8.6, 114.8) ng/ml to 4.9 (0.7, 50.3) ng/ml, (P Conclusion US-guided 125I seed implantation is safety and efficacy in treating RR- DTC. It could be an effective supplement for the comprehensive treatment of thyroid cancer.

To evaluate the diagnostic accuracy of preoperative contrast-enhanced ultrasound (CEUS) to detect extracapsular extension (ECE) and identify the relationship between ECE and nodule enhancement patterns in patients with papillary thyroid cancer (PTC). Patients with suspected thyroid cancer underwent ultrasound (US) and CEUS examinations. The US and CEUS features of the PTC nodules and thyroid capsule were recorded and classified individually. The accuracy of US and CEUS in detecting ECE was compared individually, and its relationship with various tumour enhancement patterns was analysed. The presence or absence of ECE and cervical lymph node metastasis (LNM) was confirmed pathologically. The final dataset included 119 patients with 124 PTC nodules. Seventy-two (60.5%) of these patients with PTC had no ECE (including 38 patients with single capsule invasion), while the remaining 52 had ECE. A significant difference was found in nodules with non-capsule invasion, single capsule invasion, and ECE between the cervical LNM and non-LNM groups (p < 0.01). Receiver operating characteristic curve analysis demonstrated that area under the curve (AUC) of ECE for cervical LNM was higher than that of capsule invasion (71.9% vs. 49.6%). Moreover, the CEUS images acquired to detect ECE showed higher AUC values than those of US images (79.4% vs. 65.8%) (p = 0.02). Among the PTC nodules with differential enhancement, hyper-enhanced nodules had the highest incidence of capsule invasion (41.9%), while hypo-enhanced ones had a higher incidence of ECE (47.4%). Compared with conventional US, CEUS is a more valuable and non-invasive imaging modality to detect ECE. • Single capsular invasion was a poor predictor of cervical lymph node metastasis, while extracapsular extension assessments were clinically significant for predicting cervical lymph node metastasis. • CEUS is better than conventional US in detecting extracapsular extension in papillary thyroid carcinoma (AUC: 79.4% vs. 65.8%) (p = 0.02). • Among the thyroid papillary carcinoma nodules with differential enhancement, hyper-enhanced nodules had the highest incidence of single capsule invasion (41.9%), while hypo-enhanced ones had a higher incidence of ECE (47.4%).

Objective To evaluate the efficacy of ultrasound and computed tomography (CT) in diagnosing cervical lymph node metastasis (CLNM) of papillary thyroid carcinoma (PTC). Methods The patients with PTC treated by surgery in the Chinese PLA General Hospital from January 2016 to January 2021 were selected for analysis.All the patients underwent preoperative ultrasound and CT examinations,the diagnostic values of which for CLNM were retrospectively analyzed. Results A total of 322 PTC patients were enrolled in this study,including 242 with CLNM and 80 with non-CLNM.The CLNM group and non-CLNM group had significant differences in age,tumor size,and maximum size of lateral CLNM (

Objective To evaluate the performance of micro-flow imaging(MFI)in the differential diagnosis of benign and malignant thyroid nodules. Methods Totally 50 patients with thyroid nodules examined by conventional ultrasound,MFI,and contrast-enhanced ultrasound and confirmed by histological or cytological pathology in the First Medical Center of Chinese PLA General Hospital from May to December in 2020 were enrolled in the study.The clinical data and ultrasound images were retrospectively analyzed.A binary logistic regression model was established to evaluate the performance of the model in predicting benign and malignant thyroid nodules. Results Logistic regression showed that composition and "S-W-C" sign were independent risk factors for predicting malignant thyroid nodule.The sensitivity,specificity,and Youden index of the logistic regression model were 73.33%,80.00%,and 0.53,respectively,and the area under receiver operating characteristic curve was 0.799(95%

High-risk papillary thyroid carcinoma (PTC) patients with BRAF mutation have lymph node and distant metastases and poor prognosis. Therefore, this study aims to develop a targeted ultrasound contrast agent for the BRAFThe targeted lipid nanobubbles carrying BRAFThe targeted lipid nanobubbles revealed uniform, round morphology, and good stability with a nanoscale size. Besides, BRAFThe targeted lipid nanobubbles carrying BRAF

Objective To establish an artificial intelligence model based on B-mode thyroid ultrasound images to predict central compartment lymph node metastasis(CLNM)in patients with papillary thyroid carcinoma(PTC). Methods We retrieved the clinical manifestations and ultrasound images of the tumors in 309 patients with surgical histologically confirmed PTC and treated in the First Medical Center of PLA General Hospital from January to December in 2018.The datasets were split into the training set and the test set.We established a deep learning-based computer-aided model for the diagnosis of CLNM in patients with PTC and then evaluated the diagnosis performance of this model with the test set. Result The accuracy,sensitivity,specificity,and area under receiver operating characteristic curve of our model for predicting CLNM were 80%,76%,83%,and 0.794,respectively. Conclusion Deep learning-based radiomics can be applied in predicting CLNM in patients with PTC and provide a basis for therapeutic regimen selection in clinical practice.

Objective: To compare and analyze the clinical effects of ultrasound-guided percutaneous nephrolithotripsy and X-ray-guided percutaneous nephrolithotripsy in the treatment of complex renal calculi without hydronephrosis. Methods: Eighty patients with multiple stones without hydronephrosis were admitted at Department of Ultrasound Diagnosis, The first medical center of Chinese PLA General Hospital from January 21, 2020 to December 21, 2020 randomly divided into two groups: experimental group and control group, with 40 cases in each group. Patients in the experimental group were treated with ultrasound-guided percutaneous nephrolithotomy, while those in the control group were treated with X-ray-guided percutaneous nephrolithotomy. The differences in operation time, channel establishment time, channel number, blood loss and stone clearance rate between the two groups were compared and analyzed. Venous blood was drawn before surgery and on the first day after surgery, and serum creatinine, urea nitrogen, blood β2-microglobulin, blood uric acid and other renal indexes were detected. Moreover, renal parenchymal injury was compared between the two groups by renal static imaging, and the incidence of postoperative complications such as pain, fever, urination through incision and injury of surrounding organs were compared and analyzed. Results: The operation time, channel establishment time, channel number and blood loss in the experimental group were significantly lower than those in the control group, with statistically significant differences (p

Objective To investigate the clinical value of core-needle biopsy(CNB)for low-risk papillary thyroid microcarcinoma(PTMC)after radiofrequency ablation(RFA). Methods A total of 190 patients(including 142 females and 48 males,20-74 years old)with unifocal low-risk PTMCs[mean volume of(106.29±96.15)mm

Triple-negative breast cancer is a complex type of breast cancer,the most common malignant tumor in women.Since the early image features of triple-negative breast cancer appear benign tumor with rapid growth,this cancer has progressed into the middle and late stages once diagnosed,which leads to high mortality.Therefore,the diagnosis of triple-negative breast cancer has always been a clinical difficulty.This article summarizes the role of ultrasound in the diagnosis and treatment of triple-negative breast cancer.The extracted multi-mode ultrasound features will facilitate the early detection of this cancer and improve the prognosis of these patients.

Objective To compare the health-related quality of life(HRQoL)of patients with papillary thyroid microcarcinoma(PTMC)treated by different modalities. Methods The PTMC patients after treatment who came to our department for follow-up from October to December in 2019 were enrolled and assigned into three groups according to treatment modalities:radiofrequency ablation(RFA)group(

Objective To explore the value of trans-lymphatic contrast-enhanced ultrasound(CEUS)in the diagnosis of cervical lymph node metastasis of thyroid cancer. Methods The patients with suspected thyroid cancer underwent conventional ultrasound and trans-lymphatic CEUS examinations before the biopsy.The differences in ultrasound and CEUS characteristics of cervical lymph nodes between the metastatic group and the non-metastatic group were compared,and pathological results were regarded as the golden standard. Results Twenty patients had thyroid cancer,including 12 cases with lymph node metastasis and 8 cases without metastasis.The diagnostic sensitivity(91.7%

Objective To establish a prediction model for the short-term efficacy of percutaneous ultrasound-guided radiofrequency ablation(RFA)in the treatment of papillary thyroid microcarcinoma(PTMC). Methods We retrospectively analyzed the preoperative and follow-up data of 159 patients with PTMC who underwent percutaneous ultrasound-guided RFA treatment in the Department of Ultrasound,the First Medical Center of Chinese PLA General Hospital from January to December in 2018.The association with 12-month tumor status(end event)was evaluated by multivariate logistic regression model.A nomogram was built to predict the risk of tumors which did not disappear completely within 12 months after RFA. Results We found that gender(

Objective To compare the performance of contrast-enhanced ultrasound(CEUS)and ultrasound(US)in the differential diagnosis between cholesterol polyps and gallbladder adenomas. Methods A total of 136 patients with gallbladder polyp lesions(GPLs)and undergoing cholecystectomy in the First Medical Center of Chinese PLA General Hospital from January 2019 to October 2020 were retrospectively analyzed.All the patients underwent US and CEUS examinations before cholecystectomy.US and CEUS images of cholesterol polyps and gallbladder adenomas were compared for the evaluation of the performance of CEUS in the diagnosis of gallbladder adenomas. Results The 136 cases of GPLs included 95 cases of cholesterol polyps and 41 cases of gallbladder adenomas.Cholesterol polyps and gallbladder adenomas showed significant differences in the maximum size of GPLs(

Objective To discuss the value of contrast-enhanced ultrasound(CEUS)parameters in evaluating the formation of Kimmelstiel-Wilson(K-W)nodules in diabetic nephropathy(DN).Methods Sixty-two patients pathologically diagnosed with DN and undergoing CEUS in the First Medical Center of Chinese PLA General Hospital from March 2017 to January 2020 were assigned into two groups according to whether K-W nodules were formed.The cortical CEUS parameters and the ratios of cortical to medullary CEUS parameters were compared between the two groups.Results The 62 patients included 19 patients without K-W nodules(group A)and 43 patients with K-W nodules(group B).The median rise time(

Objective To explore the association between contrast-enhanced ultrasound and risk of tumor recurrence in papillary thyroid carcinoma(PTC). Methods A total of 287 PTCs in 287 patients who underwent surgery,conventional ultrasound,and contrast-enhanced ultrasound(CEUS)were enrolled in this study.According to 2015 American Thyroid Association(ATA)Modified Initial Risk Stratification System,the patients were categorized into three groups:low risk,intermediate risk,and high risk.The CEUS patterns of PTCs were compared between different risk stratifications. Results Hypo-enhancement was presented in 57.6% of ATA low-risk PTCs,iso-enhancement in 62.3% of ATA intermediate-risk PTCs,and hyper-enhancement in 48.2% of ATA high-risk PTCs(

Objective To investigate the correlation of routine ultrasound features and BRAFV600E gene to the cervical lymph node metastasis (CLNM) of thyroid papillary carcinoma (PTC). Methods A hundred and seven patients with thyroid papillary carcinoma who underwent thyroid gland resection and cervical lymph node dissection in the First Medical Center of Chinese PLA General Hospital from January to December 2018 were recruited as study subjects, including 56 patients in the metastatic group and 51 patients in the non-metastatic group. Ultrasound examination and BRAFV600E gene detection were performed, and the indicators obtained were compared between the two groups including gender, age, focus position (upper middle or inferior), close to the capsule or to the isthmus, focus located in the left or right lobes, single or multiple, maximum diameter, aspect ratio, boundary, shape, internal echo, internal components, peripheral halos, calcification, microcalcification, color Doppler features, Hashimoto's disease, and BRAFV600E gene mutation. Logistic regression analysis was conducted for gender, age, close to the capsule or to the isthmus, maximum diameter, shape, calcification, microcalcification, color Doppler features, Hashimoto's disease, and BRAFV600E gene mutation to establish a predictive model of cervical lymph node metastasis in patients with thyroid papillary carcinoma, and the predictive efficacy of the model was evaluated. Results The results compared between the two groups showed that statistically significant differences existed in gender, age, maximum diameter of the lesion, close to capsule, close to isthmus, shape, acoustic halo, calcification and microcalcification (P

Background The patient satisfaction of symptoms improvement and disease factors that may affect long-term treatment efficacy of radiofrequency ablation (RFA) for non-functioning solid benign thyroid nodules (TNs) over a 2-year follow up study was investigated. Methods This retrospective study evaluated 194 non-functioning solid benign TNs of 103 patients. The TNs were categorized as small (≤5 ml), medium (5.1 to 13 ml), intermediate (13.1 to 30 ml) and large (over 30 ml) according to the initial volume of TNs before ablation. Clinical evaluation and contrast-enhanced ultrasound (CEUS) were carried out before ablation and the follow up at 1, 3, 6 months and every 6 months after ablation. All patients were asked to assess the cosmetic score (1–4 scores) and symptom score (0–10 scores) before ablation and every follow up after ablation. Results All patients underwent RFA without any major complications. The mean treatment sessions were 1.5 ± 0.6. 98 nodules required a single session (98/194, 50.5%), 87 required two sessions (87/194, 44.9%), 9 required three sessions (9/194, 4.6%). The average follow up months were 16.3 ± 5.6 (range, 6–24 months) and no nodule regrew in our study. After RFA treatment, the TNs volume significantly decreased (P

Background: Treatment for radioiodine refractory differentiated thyroid carcinoma (RR-DTC) is challenging. The purpose of this study was to assess the efficacy and safety of ultrasound-guided implantation of radioactive 125I-seed in radioiodine refractory differentiated thyroid carcinoma.Methods: 36 cervical metastatic lymph nodes (CMLNs) diagnosed as RR-DTC from 18 patients were enrolled in this retrospective study. US and contrast-enhanced ultrasound (CEUS) examinations were performed before implantation. Follow-up consisted of US, CEUS, thyroglobulin (Tg) level and routine hematology at 1-3, 6, 9 and 12 months and every 6 months thereafter. The volumes of the nodules were compared before implantation and at each follow-up point. The volume reduction rate (VRR) of nodules was also recorded.Results: The median volume of the nodules was 522.8 mm3 (147.5, 2009.6mm3) initially, which decreased significantly to 53.0mm3 (0, 285.7mm3) (P < 0.01) at the follow-up point of 24 months with a mean VRR as 87.4±18.1% (the range was 32–100%). During the follow-up period (the range was 24–50 months), 25 (69%) nodules had VRR greater than 90%, of which 12 (33%) nodules had VVR≈100% with structures unclear and only 125I seeds images visible. At the last follow-up visit, the serum Tg level decreased from 57.0 (8.6, 114.8) ng/ml to 4.9 (0.7, 50.3) ng/ml, (P < 0.01).Conclusion: US-guided 125I seed implantation is safety and efficacy in treating RR- DTC. It could be an effective supplement for the comprehensive treatment of thyroid cancer.

Objective To investigate the short-term outcome of T1bN0M0 papillary thyroid cancer after ultrasonography-guided radiofrequency ablation(RFA). Methods Eighty-nine patients with T1bN0M0 papillary thyroid cancer who were treated with ultrasonography-guided RFA in our center from April 2014 to January 2019 were retrospectively analyzed.Trans-isthmus approach and moving shot technique were used during the RFA procedure.Ultrasonography and contrast-enhanced ultrasonography were performed before ablation,and immediately,1,3,6 and 12 months after ablation and then every 6 months thereafter. Results RFA was performed in 89 cases of papillary thyroid cancer,and no major complications were observed during the RFA.The mean follow-up was(18.8±7.3)months.The ablation zones decreased gradually during follow-up,and 38 ablation zones(42.7%)completely disappeared.The volume reduction rate was(99.2±2.3)% 30 months after ablation.During follow-up,2 patients(2.2%)developed tumor recurrence and 1 patient(1.1%)developed cervical lymph node metastasis. Conclusion Ultrasonography-guided RFA may be a safe and effective method for patients with T1bN0M0 papillary thyroid cancer.

Objectives: To investigate the clinical value of Superb Microvascular Imaging (SMI) combined with low dose CT scanning in differential diagnosis of thyroid lesions and tumor staging. Methods: A total of 120 patients with thyroid nodules admitted to the Chinese PLA General Hospital from January 2017 to July 2020 were selected. Paired design was adopted in this study. SMI and SMI combined with low-dose CT scanning were respectively carried out to these patients. The results were judged by two senior imaging physicians and two senior sonographers respectively. And t-test, χ2 test, Pearson correlation coefficient check and other methods were adopted to comparatively analyze the above two methods and the pathological results after operation or puncture. Results: Compared with pathologic findings, the coincidence rate of SMI was 40%, and the coincidence rate of SMI combined with low dose CT scanning was 84%. The difference was significant (p=0.00); among the 120 thyroid nodule patients, 50 were diagnosed as malignant by pathological diagnosis, and 70 as benign; 27 malignant cases and 93 benign cases were detected by SMI; 48 malignant cases and 72 benign cases were detected by SMI combined with low dose CT scanning. The sensitivity and accuracy of the latter were significantly higher than those of the former, and the difference was statistically significant (p=0.00); the enhancement, edge sharpness and homogeneity of SMI increased with the increase of tumor malignancy, showing positive correlation property. Conclusion: SMI combined with low dose CT scanning has a higher diagnostic coincidence rate. Its sensitivity and accuracy are significantly superior. With the increase of tumor malignancy, the enhancement and unhomogeneity of SMI increase, and the edge is more blurred. That suggests: with the increase of tumor malignancy, neovascularization in the tumor is more obvious and more unevenly distributed; the increase of edge blur indicates more obvious tumor infiltration. The method has considerable clinical value for predicting the malignancy of tumors. doi: https://doi.org/10.12669/pjms.37.5.4144 How to cite this:Xue SW, Luo YK, Jiao ZY, Xu L. Clinical value of SMI Combined with Low-Dose CT Scanning in differential diagnosis of Thyroid Lesions and Tumor Staging. Pak J Med Sci. 2021;37(5):1347-1352. doi: https://doi.org/10.12669/pjms.37.5.4144 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

This study aimed to evaluate the diagnostic performance of high frame rate contrast-enhanced ultrasound (H-CEUS) of focal liver lesions (FLLs).From July 2017 to June 2019, conventional contrast-enhanced ultrasound (C-CEUS) and H-CEUS were performed in 78 patients with 78 nodules. The characteristics of C-CEUS and H-CEUS in malignant and benign groups and the differences between different lesion sizes (1-3 cm, 3-5 cm, or5 cm) of C-CEUS and H-CEUS were examined. The diagnostic performance of C-CEUS and H-CEUS was analyzed. The chi-square test or Fisher's exact test was used to assess inter-group differences. The receiver operating characteristic curve was plotted to determine the diagnostic performance of C-CEUS and H-CEUS.There were significant differences in the enhancement area, fill-in direction and vascular architecture between C-CEUS and H-CEUS for both benign and malignant lesions (allH-CEUS provided more vascular information which could help differentiate malignant from benign FLLs, especially for lesions 1-3 cm in size.

To compare the diagnostic value of high frame rate contrast-enhanced ultrasound (H-CEUS) in distinguishing gallbladder adenomas from cholesterol polyp lesions with that of CEUS.This study enrolled 94 patients with gallbladder polyp lesions (GPLs) who underwent laparoscopic cholecystectomy. CEUS and H-CEUS were performed before surgery. The perfusion features of GPLs and the final diagnosis as determined by both technologies were compared.There were differences in vascular types between gallbladder adenomas and cholesterol polyp lesions observed on H-CEUS (p0.05), while there were no differences in vascular types between gallbladder adenomas and cholesterol polyp lesions observed on CEUS (p0.05). In the cholesterol polyp lesion group, there were no differences in vascular types between CEUS and H-CEUS (p0.05), while the vascular types were different between CEUS and H-CEUS in the gallbladder adenoma group (p0.05). The diagnostic value of H-CEUS in distinguishing gallbladder adenomas from cholesterol polyp lesions was better than that of CEUS.H-CEUS improved the time resolution by increasing the frame rate, which helped to accurately reflect the difference in the microcirculation of GPLs and improved the ability of a differential diagnosis between cholesterol polyp lesions and adenomas. H-CUES may provide an effective means of imaging for patients with GPLs regarding the choice of treatment options.• High frame rate CEUS improves the time resolution of CEUS by increasing the frame rate. • High frame rate CEUS is helpful to accurately evaluate the microvascular morphology of a gallbladder polyp lesion in the arterial phase. • High frame rate CEUS helps patients with gallbladder polyp lesions to choose the appropriate treatment means.

Objective: To explore the role of musculoskeletal ultrasound (MSUS) in the differential diagnosis of gouty arthritis (GA) and rheumatoid arthritis (RA) and to analyze the ultrasound imaging features of the two diseases. Methods: A retrospective study was carried out. A total of 66 patients who had been admitted to The First Medical Center of Chinese PLA General Hospital from May 2018 to March 2019 were enrolled. Among them, 34 patients were diagnosed with RA and were included in the RA group; 32 patients were diagnosed with gouty arthritis and were included in the GA group. The imaging features of musculoskeletal ultrasound were compared between the two groups of patients. Results: A total of 34 patients were included in the RA group, including 17 males and 17 females. A total of 32 patients were included in the GA group, including 14 males and 18 females. There were no significant differences in gender composition, age, and duration of disease between the two groups (P>0.05). In the RA group, there were joint bone erosions with a clear boundary in seven cases and with a blurred boundary in 27 cases; synovial hyperplasia was observed in 27 cases, and point-like hyperechoic masses were observed in four cases. In the GA group, there were joint bone erosions with a clear boundary in 27 cases and with a blurred boundary in five cases; synovial hyperplasia was observed in four cases, tophus was observed in 23 cases, point-like hyperechoic masses were observed in 27 cases, and the tram-track sign was observed in 23 cases. The differences in bone erosion boundaries (c2=26.854, P

To analyze the potential associations of ultrasound-guided fine-needle aspiration(FNA),BRAF

Objective To compare the values of elasticity imaging(EI)and Virtual Touch

Grazing is one of the most important ways for managing grassland in northern China. Different studies have focused on the effects of grazing on the structure and function of ecosystems. Grazing affects the structure and function of soil via biological and physical processes, such as animal trampling, feeding, and excretion, which further affects N

Gross ammonification (GA) and gross nitrification (GN) are key regulators of the bioavailability of nitrogen (N) in terrestrial ecosystems. In arid and semi-arid grassland ecosystems, the impacts of precipitation change on in situ GA and GN and their seasonal variations are understudied. A manipulative experiment with five precipitation levels (−60%, −30%, unchanged ambient precipitation as control, +30%, +60% of ambient precipitation) was set up in May 2012. After a 2-year equilibration period, the 15N pool dilution technique was applied to determine GA and GN rates in surface soil (0–5 cm) within 8 sampling dates ranging from the onset to the end of the growing season. Pronounced temporal variability of GA and GN rates were observed with the highest GA and GN rates in the mid-growing season (August) and the lowest in the post-growing season (October). GA rates during the growing season were primarily controlled by precipitation and soil water availability, while this effect diminished at the onset and end of the growing season when the temperature dropped. In contrast, GN was predominately controlled by ammonium (NH4+) production through GA. In the peak-growing season, the +60% precipitation treatment enhanced GA and GN rates by up to 4-fold, while the −30% precipitation treatment marginally suppressed GA and GN rates. The −60% precipitation treatment suppressed GA and GN rates to below detection limits across the entire study period, suggesting that extreme and persistent droughts greatly inhibited N turnover in the surface soil, thereby forcing plants to mobilize and access nutrients from deeper soil layers. Our findings provide a season-specific mechanistic insight into precipitation impacts on topsoil gross N turnover and suggest that the N cycling represented in ecosystem models needs to consider a mechanism that allows a strong suppression of microbial functions under extreme droughts.

Objective To evaluate the safety and feasibility of radiofrequency ablation (RFA) for hepatic pedicle lesioning in combination with hepatic artery clamping for precise liver resection by establishing a model of precise liver resection in animals. Methods Six healthy Guangxi Bama miniature pigs were selected for this study, and S3, S5 and S6 used as target hepatic segments. The hepatic pedicles were lesioned by radioablation under ultrasound guidance. The hepatic artery was clamped temporarily at the time of radioablation. Three segments (S3, S5 and S6) were resected on each pig. The main outcome measures included the local and general tolerance, the change of blood flow parameters of each segmental arterial and portal branches, and the microscopic appearance of the segmental arterial, portal and biliary tract branches. Results There was no any complication or death following RFA application, and the liver function was restored to normal 14 days after the operation in all animals. Demarcation areas were clear in all target hepatic segments. The blood flow velocity of the portal branches was 0cm/s in all the target hepatic segments after RFA. The arterial blood flow velocity was 15.1±15.4cm/s, which was significantly lower compared with that before RFA (P>0.000). There was no difference in the flow rate of the unaffected segmental vessels following RFA. The mean ablated length of segmental portal, arterial and biliary tract branches was 1.7±0.5cm, 1.4±0.4cm, 1.6±0.4cm, respectively. Conclusions The technique is expedient, safe and effective. Simultaneous temporary occlusion of the hepatic artery adds further benefit. The probe needs to be at least 1.5cm away from non targeted structures to avoid unintended thermal injury. DOI: 10.11855/j.issn.0577-7402.2016.08.05