Deep learning radiomics model based on breast ultrasound video to predict HER2 expression status.

Purpose: The detection of human epidermal growth factor receptor 2 (HER2) expression status is essential to determining the chemotherapy regimen for breast cancer patients and to improving their prognosis. We developed a deep learning radiomics (DLR) model combining time-frequency domain features of ultrasound (US) video of breast lesions with clinical parameters for predicting HER2 expression status. Patients and Methods: Data for this research was obtained from 807 breast cancer patients who visited from February 2019 to July 2020. Ultimately, 445 patients were included in the study. Pre-operative breast ultrasound examination videos were collected and split into a training set and a test set. Building a training set of DLR models combining time-frequency domain features and clinical features of ultrasound video of breast lesions based on the training set data to predict HER2 expression status. Test the performance of the model using test set data. The final models integrated with different classifiers are compared, and the best performing model is finally selected. Results: The best diagnostic performance in predicting HER2 expression status is provided by an Extreme Gradient Boosting (XGBoost)-based time-frequency domain feature classifier combined with a logistic regression (LR)-based clinical parameter classifier of clinical parameters combined DLR, particularly with a high specificity of 0.917. The area under the receiver operating characteristic curve (AUC) for the test cohort was 0.810. Conclusion: Our study provides a non-invasive imaging biomarker to predict HER2 expression status in breast cancer patients.

Evaluation of the role of postoperative radiotherapy in locally invasive thymoma: A propensity-matched study based on the SEER database.

OBJECTIVES: No consensus was reached on the efficacy of postoperative radiotherapy (PORT) in locally invasive thymomas because of the rarity of the thymic epithelial and the variations of study results. Therefore, we aimed to explore the efficacy of PORT in locally invasive thymomas using the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: Patients diagnosed with thymomas from 2004 to 2016 were identified using the SEER database. Prognostic factors of cancer-specific survival (CSS) and overall survival (OS) were identified using univariate and multivariate Cox regression analyses.Propensity score matching (PSM) was performed to balance the baseline characteristics. RESULTS: A total of 700 eligible patients were identified. After PSM, 262 paired patients were selected from the two groups, those who received or did not receive PORT. Receiving PORT improved CSS and OS before and after PSM. In the matched population, the multivariate analyses showed that tumour invasion into adjacent organs/structures and non-utilisation of PORT were independent poor prognostic factors for CSS, whereas age ≥62 years,tumour invasion into adjacent organs/structures, and non-utilisation of PORT were independently associated with poorer OS. The subgroup analysis revealed that PORT improved CSS and OS in Masaoka-Koga stage III thymoma, but showed no OS benefit in Masaoka-Koga stage IIB thymoma. CONCLUSION: Based on the SEER database, we found that PORT provides a significant survival benefit in Masaoka-Koga stage III thymoma with complete or incomplete resection. The role of PORT in thymoma requires further evaluation.

Adjuvant radiotherapy shows benefit in selected stage I uterine sarcoma: A risk scoring system based on a population analysis.

BACKGROUND: The potential therapeutic benefit of adjuvant radiotherapy for patients with stage I uterine sarcoma has not been clear. In this study, we aimed to develop a risk scoring model to select the subgroup of patients with stage I uterine sarcoma who might benefit from adjuvant radiotherapy. METHODS: Patients with stage I uterine sarcoma from the Surveillance, Epidemiology, and End Results program from 2010 to 2014 were retrospectively included in this analysis. Cox proportional hazards models were performed to identify risk factors. RESULTS: A total of 947 stage I uterine sarcoma patients were included. The 5-year disease-specific survival (DSS) of the overall cohort was 75.81%. Multivariate analysis identified stage (p = 0.013), tumor grade (p <0.001) and histology (p = 0.043) as independent prognostic factors for DSS, and these factors were used to generate the risk scoring model. The low-risk group presented a better DSS than the high-risk group (95.51% vs. 49.88%, p < 0.001). The addition of radiotherapy to surgery significantly increased the DSS in the high-risk group compared with surgery alone (78.06% vs. 46.88%, p = 0.022), but no significant survival benefit was observed in the low-risk group (98.36% vs. 100%, p = 0.766). CONCLUSIONS: Our risk scoring model based on stage, tumor grade, and histology predicted the outcome of patients with stage I uterine sarcoma cancer. This system may help to select stage I uterine sarcoma cancer patients who might benefit from adjuvant radiotherapy.

Application of preoperative ultrasound features combined with clinical factors in predicting HER2-positive subtype (non-luminal) breast cancer.

BACKGROUND: Human epidermal growth factor receptor2+ subtype breast cancer has a high degree of malignancy and a poor prognosis. The aim of this study is to develop a prediction model for the human epidermal growth factor receptor2+ subtype (non-luminal) of breast cancer based on the clinical and ultrasound features related with estrogen receptor, progesterone receptor, and human epidermal growth factor receptor2. METHODS: We collected clinical data and reviewed preoperative ultrasound images of enrolled breast cancers from September 2017 to August 2020. We divided the data into in three groups as follows. Group I: estrogen receptor ± , Group II: progesterone receptor ± and Group III: human epidermal growth factor receptor2 ± . Univariate and multivariate logistic regression analyses were used to analyze the clinical and ultrasound features related with biomarkers among these groups. A model to predict human epidermal growth factor receptor2+ subtype was then developed based on the results of multivariate regression analyses, and the efficacy was evaluated using the area under receiver operating characteristic curve, accuracy, sensitivity, specificity. RESULTS: The human epidermal growth factor receptor2+ subtype accounted for 138 cases (11.8%) in the training set and 51 cases (10.1%) in the test set. In the multivariate regression analysis, age ≤ 50 years was an independent predictor of progesterone receptor + (p = 0.007), and posterior enhancement was a negative predictor of progesterone receptor + (p = 0.013) in Group II; palpable axillary lymph node, round, irregular shape and calcifications were independent predictors of the positivity for human epidermal growth factor receptor-2 in Group III (p = 0.001, p = 0.007, p = 0.010, p < 0.001, respectively). In Group I, shape was the only factor related to estrogen receptor status in the univariate analysis (p < 0.05). The area under receiver operating characteristic curve, accuracy, sensitivity, specificity of the model to predict human epidermal growth factor receptor2+ subtype breast cancer was 0.697, 60.14%, 72.46%, 58.49% and 0.725, 72.06%, 64.71%, 72.89% in the training and test sets, respectively. CONCLUSIONS: Our study established a model to predict the human epidermal growth factor receptor2-positive subtype with moderate performance. And the results demonstrated that clinical and ultrasound features were significantly associated with biomarkers.

An Ultrasound Radiomics Nomogram for Preoperative Prediction of Central Neck Lymph Node Metastasis in Papillary Thyroid Carcinoma.

Purpose: This study aimed to establish and validate an ultrasound radiomics nomogram for the preoperative prediction of central lymph node (LN) metastasis in patients with papillary thyroid carcinoma (PTC). Patients and Methods: The prediction model was developed in 609 patients with clinicopathologically confirmed unifocal PTC who received ultrasonography between Jan 2018 and June 2018. Radiomic features were extracted after the ultrasonography of PTC. Lasso regression model was used for data dimensionality reduction, feature selection, and radiomics signature building. The predicting model was established based on the multivariable logistic regression analysis in which the radiomics signature, ultrasonography-reported LN status, and independent clinicopathologic risk factors were incorporated, and finally a radiomics nomogram was established. The performance of the nomogram was assessed with respect to the discrimination and consistence. An independent validation was performed in 326 consecutive patients from July 2018 to Sep 2018. Results: The radiomics signature consisted of 23 selected features and was significantly associated with LN status in both primary and validation cohorts. The independent predictors in the radiomics nomogram included the radiomics signature, age, TG level, TPOAB level, and ultrasonography-reported LN status. The model showed good discrimination and consistence in both cohorts: C-index of 0.816 (95% CI, 0.808-0.824) in the primary cohort and 0.858 (95% CI, 0.849-0.867) in the validation cohort. The area under receiver operating curve was 0.858. In the validation cohort, the accuracy, sensitivity, specificity and AUC of this model were 0.812, 0.816, 0.810, and 0.858 (95% CI, 0.785-0.930), respectively. Decision curve analysis indicated the radiomics nomogram was clinically useful. Conclusion: This study presents a convenient, clinically useful ultrasound radiomics nomogram that can be used for the pre-operative individualized prediction of central LN metastasis in patients with PTC.

Patterns of supraclavicular area failure after mastectomy in breast cancer patients: implications for target volume delineation.

PURPOSE: To characterize the pattern of post-mastectomy supraclavicular lymph node (LN) metastases in patients with breast cancer (BC) and to provide insights for individualized clinical target volume delineation for radiotherapy. METHODS: We retrospectively analyzed 88 patients with BC who developed post-mastectomy regional LN metastases. The affected regional LNs were categorized as the ipsilateral medial supraclavicular LN area (IMSC-LN), ipsilateral lateral supraclavicular LN area (ILSC-LN), ipsilateral infraclavicular LN area (IIC-LN), and ≥2 groups in the ipsilateral clavicular LN area (MMIC-LN). Clinical characteristics were included in a multivariate analysis to identify risk factors for clavicular LN metastases. RESULTS: The ILSC-LNs (68.2%) were the most common metastatic site. IMSC-LN metastases showed a significant association with estrogen-receptor (ER) negative status, left-sided BC, and positive axillary LNs. Tumor size ≥2.4 cm and Her2 type were predictors of ILSC-LN metastases. Additionally, tumor size ≥2.4 cm, and level I ipsilateral axillary metastases were associated with MMIC-LN metastasis. CONCLUSION: ILSC-LN was the most frequently affected group of supraclavicular lymph nodes. ER-negative status, left-sided BC, tumor size, and positive ipsilateral axillary LNs are potentially associated with the pattern of supraclavicular LN metastatic involvement.

Prognostic factors and treatment comparison in small cell neuroendocrine carcinoma of the uterine cervix based on population analyses.

OBJECTIVE: We aimed to assess the impact of the treatment modality on the outcome of small cell neuroendocrine cervical carcinoma (SCNEC) using the Surveillance Epidemiology and End Results (SEER) database. METHODS: Patients from the SEER program between 1981 and 2014 were identified. Significant factors for cancer-specific survival (CSS) and overall survival (OS) were analyzed using the Kaplan-Meier survival and Cox regression methods. RESULTS: A total of 503 SCNEC patients were identified. The 5-year CSS and OS were 36.6% and 30.6%, respectively. The International Federation of Gynecology and Obstetrics (FIGO) stage I to IV distributions was 189 (37.6%), 108 (21.5%), 95 (18.9%), and 111 patients (22.0%), respectively. Within the patients with known treatment strategies, 177 (45.9%) were treated with radical surgery and 209 (54.1%) underwent primary radiotherapy. Local treatment strategies were independent prognostic factor for CSS and OS. The 5-year CSS for radical surgery and primary radiotherapy was 50.0% and 27.9%, respectively (P < .001). The 5-year OS for those who received radical surgery and primary radiotherapy was 57.8%, and 29.6%, respectively (P < .001). In FIGO stage I SCNEC, patients treated with radical surgery had superior CSS (P = .001) and OS (P = .003) than those with primary radiotherapy. However, in FIGO stage II and III SCNEC, there were no differences in CSS and OS with respect to different local treatment strategies. Our results also found that the addition of brachytherapy impacted OS in the FIGO stage III SENCE (P = .002). The 5-year CSS and OS of patients with FIGO IV were only 11.7% and 7.1%, respectively. CONCLUSIONS: SCNEC is a rare disease with aggressive clinical behavior. The findings indicate that radical surgery should be suggested for early-stage SCNEC and combining radiation therapy with brachytherapy should be suitable for patients with advanced stage.

High Biologically Effective Dose Radiotherapy for Brain Metastases May Improve Survival and Decrease Risk for Local Relapse Among Patients With Small-Cell Lung Cancer: A Propensity-Matching Analysis.

To evaluate whether high biologically effective dose (BED) radiotherapy improves local control and survival outcomes for patients with brain metastases (BMs) from small-cell lung cancer (SCLC) and to determine possible prognostic factors. From January 1998 to June 2018, 250 patients with BM from SCLC were retrospectively analyzed. The Cutoff Finder program was used to classify patients by BED. Overall survival (OS) and BM progression-free survival (BM-PFS) were analyzed using the Kaplan-Meier method and log-rank test. A Cox regression model was used to calculate the hazard ratio and 95% CI for prognostic factors for OS among the study population and propensity score (PS)-matched patients. A BED of 47.4 was taken as the optimal cutoff value. Both OS and BM-PFS were significantly improved in the high-BED (>47.4 Gy) than in the low-BED (≤47.4 Gy) group (median OS: 17.5 months vs 9.5 months, P < .001, median BM-PFS: 14.4 months vs 8.3 months, P < .001). Biologically effective dose (P < .001), Eastern Cooperative Oncology Group performance status (P = .047), smoking (P = .005), and pleural effusion (P = .004) were independent prognostic factors for OS. Propensity score matching with a ratio of 1:2 resulted in 57 patients in the high-BED group and 106 patients in the low-BED group. In the PS-matched cohort, OS and BM-PFS were significantly prolonged in the high-BED group compared with the low-BED group (P < .001). Biologically effective dose >47.4 Gy improves survival among patients with BM from SCLC. Eastern Cooperative Oncology Group score, smoking, and pleural effusion independently affect OS of SCLC patients with BM.

The Role of Contrast-Enhanced Ultrasound in the Diagnosis and Pathologic Response Prediction in Breast Cancer: A Meta-analysis and Systematic Review.

PURPOSE: To determine the overall performance of contrast-enhanced ultrasound (CEUS) in differentiating between benign and malignant breast lesions and in predicting the pathologic response to neoadjuvant chemotherapy (NAC) in patients with breast cancer (BC). MATERIALS AND METHODS: Articles published up to April 2019 were systematically searched in Medline, Web of Science, and China National Knowledge Infrastructure. The sensitivities and specificities across studies, the calculations of positive and negative likelihood ratios (LR+ and LR-), diagnostic odds ratio (OR), and constructed summary receiver operating characteristic curves were determined. Methodologic quality was assessed using the QUADAS (Quality Assessment of Diagnostic Accuracy Studies) tool. Subgroup analyses and metaregression were performed on prespecified study-level characteristics. RESULTS: Fifty-one studies involving 4875 patients with 5246 breast lesions and 10 studies involving 462 patients with BC receiving NAC were included. Methodologic quality was relatively high, and no publication bias was detected. The overall sensitivity, specificity, diagnostic OR, LR+, and LR- for CEUS were 0.88 (95% confidence interval [CI], 0.86-0.89), 0.82 (95% CI, 0.80-0.83), 30.55 (95% CI, 21.40-43.62), 4.29 (95% CI, 3.51-5.25), and 0.16 (95% CI, 0.13-0.21), respectively, showing statistical heterogeneity. Multivariable metaregression analysis showed contrast mode to be the most significant source of heterogeneity. The overall sensitivity, specificity, LR+, LR, and diagnostic OR of CEUS imaging in predicting the overall pathologic response to NAC in patients with BC were 0.89 (95% CI, 0.83-0.93), 0.83 (95% CI, 0.78-0.88), 4.49 (95% CI, 3.04-6.62), 0.16 (95% CI, 0.10-0.24,), and 32.21 (95% CI, 16.74-62.01), respectively, showing mild heterogeneity. CONCLUSION: Our data confirmed the excellent performance of breast CEUS in differentiating between benign and malignant breast lesions as well as pathologic response prediction in patients with BC receiving NAC.

Development and Validation of a Simple-to-Use Nomogram for Predicting the Upgrade of Atypical Ductal Hyperplasia on Core Needle Biopsy in Ultrasound-Detected Breast Lesions.

BACKGROUND: The rate of carcinoma upgrade for atypical ductal hyperplasia (ADH) diagnosed on core needle biopsy (CNB) is variable on open excision. The purpose of the present study was to develop and validate a simple-to-use nomogram for predicting the upgrade of ADH diagnosed with ultrasound (US)-guided core needle biopsy in patients with US-detected breast lesions. METHODS: Two retrospective sets, the training set (n = 401) and the validation set (n = 186), from Fudan University Shanghai Cancer Center between January 2014 and December 2019 were retrospectively analyzed. Clinicopathological and US features were selected using univariate and multivariable logistic regression, and the significant features were incorporated to build a nomogram model. Model discrimination and calibration were assessed in the training set and validation set. RESULTS: Of the 587 ADH biopsies, 67.7% (training set: 267/401, 66.6%; validation set: 128/186, 68.8%) were upgraded to cancers. In the multivariable analysis, the risk factors were age [odds ratio (OR) 2.739, 95% confidence interval (CI): 1.525-5.672], mass palpation (OR 3.008, 95% CI: 1.624-5.672), calcifications on US (OR 4.752, 95% CI: 2.569-9.276), ADH extent (OR 3.150, 95% CI: 1.951-5.155), and suspected malignancy (OR 4.162, CI: 2.289-7.980). The model showed good discrimination, with an area under curve (AUC) of 0.783 (95% CI: 0.736-0.831), and good calibration (p = 0.543). The application of the nomogram in the validation set still had good discrimination (AUC = 0.753, 95% CI: 0.666-0.841) and calibration (p = 0.565). Instead of surgical excision of all ADHs, if those categorized with the model to be at low risk for upgrade were surveillanced and the remainder were excised, then 63.7% (37/58) of surgeries of benign lesions could have been avoided and 78.1% (100/128) malignant lesions could be treated in time. CONCLUSIONS: This study developed a simple-to-use nomogram by incorporating clinicopathological and US features with the overarching goal of predicting the probability of upgrade in women with ADH. The nomogram could be expected to decrease unnecessary surgery by nearly two-third and to identify most of the malignant lesions, helping guide clinical decision making with regard to surveillance versus surgical excision of ADH lesions.

Role of postoperative radiotherapy in pT3N0 rectal cancer: A risk-stratification system based on population analyses.

The impact of adjuvant radiotherapy in pT3N0 rectal cancer is controversial. We aimed to determine the risk factors for cancer-specific survival (CSS) among these patients and to develop a risk-stratification system to identify which of these patients would benefit from adjuvant radiotherapy. In this review of the Surveillance, Epidemiology, and End Results database (2010-2014), we analyzed the data of pT3N0 rectal cancer patients who had not undergone neoadjuvant radiotherapy. Prognostic factors were identified using the Cox proportional hazards model, and risk scores were derived according to the ß regression coefficient. A total of 1021 patients were identified from the database search. The overall 5-year CSS was 86.31%. Multivariate analysis showed that age (P < 0.001), tumor differentiation (P = 0.044), number of nodes resected (P = 0.032), marital status (P = 0.005), and radiotherapy (P = 0.006) were independent prognostic factors for CSS. A risk-stratification system composed of age, tumor differentiation, and number of nodes resected was generated. Low-risk patients had better CSS than high-risk patients (92.13% vs 72.55%, P < 0.001). The addition of radiotherapy to surgery doubled the CSS among the high-risk patients (42.06% vs 91.26%, P = 0.001) but produced no survival benefit among the low-risk patients (93.36% vs 96.38%, P = 0.182). Our risk-stratification model based on age, tumor differentiation, and number of nodes resected predicted the outcomes of pT3N0 rectal cancer patients. This model could help identify patients who may benefit from adjuvant radiotherapy.

Prolyl hydroxylase domain 3 influences the radiotherapy efficacy of pancreatic cancer cells by targeting hypoxia-inducible factor-1α.

PURPOSE: Pancreatic cancer is characterized by a hypoxic microenvironment and resistance to most currently available treatment modalities. Prolyl hydroxylase domain 3 (PHD3) is a rate-limiting enzyme that regulates the degradation of hypoxia-inducible factors (HIFs) and is deregulated in pancreatic cancer cells. Whether such alteration of PHD3 expression contributes to the sustained growth and radioresistance of pancreatic cancer cells remains largely unknown. MATERIALS AND METHODS: PHD3 was overexpressed in pancreatic cancer Mia-paca2 cells via lentiviral expression. Cell cycle progression and apoptosis were assayed by flow cytometry. HIF-1α, EGFR, and PHD3 protein expression was assessed by Western blotting. Cell survival was determined in a colony formation assay. RESULTS: PHD3 overexpression suppressed HIF-1α protein expression and EGFR phosphorylation and enhanced the 2 Gy irradiation-mediated reductions in HIF-1α and phosphorylated (p)-EGFR under either normoxic or hypoxic conditions. PHD3 overexpression inhibited the growth and colony formation of Mia-paca2 cells in response to irradiation under either normoxic or hypoxic conditions. PHD3 overexpression exacerbated irradiation-induced apoptosis, with a greater effect under hypoxia than normoxia. Cell cycle distribution analysis demonstrated that PHD3 overexpression resulted in further shortened S phase and lengthened G2/M phase in response to irradiation. CONCLUSION: PHD3 expression may contribute to the radiotherapy efficacy of pancreatic cancer cells and serve as a novel biomarker for improving radiotherapy efficacy in pancreatic cancer.

Prognostic value of vascular endothelial growth factor receptor 1 and class III ß-tubulin in survival for non-metastatic rectal cancer.

AIM: To assess the long-term prognostic value of vascular endothelial growth factor receptor 1 (VEGFR1) and class III ß-tubulin (TUBB3) mRNA expression in non-metastatic rectal cancer. METHODS: A total of 75 consecutive patients with non-metastatic rectal cancer from March 2004 to November 2008 were analyzed retrospectively at our institute. The mRNA expressions of VEGFR1 and TUBB3 were detected by multiplex branched DNA liquid-chip technology. The Cutoff Finder application was applied to determine cutoff point of mRNA expression. SPSS software version 22.0 was used for analysis. RESULTS: The median follow-up was 102.7 mo (range, 6-153.6). The χ2 and Fisher's exact tests showed that VEGFR1 expression was related to lymph node metastasis (P = 0.013), while no relationships between TUBB3 and clinicopathological features were observed. Univariate analysis showed that T stage, lymph node metastasis, tumor differentiation, VEGFR1 and TUBB3 mRNA expression were correlated to overall survival (OS) (P = 0.048, P = 0.003, P = 0.052, P = 0.003 and P = 0.015, respectively). Also, lymph node metastasis and VEGFR1 expression independently influenced OS by multivariate analysis (P = 0.027 and P = 0.033). VEGFR1 expression was positively correlated with TUBB3 (P = 0.024). The patients with low expression of both TUBB3 and VEGFR1 presented a better OS (P = 0.003). In addition, the receiver operating characteristic analysis suggested that the combination of lymph node metastasis and VEGFR1 had a more favorable prognostic value (P < 0.001). CONCLUSION: VEGFR1 expression and lymph node metastasis independently and jointly affect survival. Moreover, low expression of VEGFR1 and TUBB3 presented a better OS in patients with non-metastatic rectal cancer, which might serve as a potential prognostic factor.

Survival benefit of re-irradiation in esophageal Cancer patients with Locoregional recurrence: a propensity score-matched analysis.

BACKGROUND: To investigate the treatment failure pattern and factors influencing locoregional recurrence of esophageal squamous cell carcinoma (ESCC) and examine patient survival with re-irradiation (re-RT) after primary radiotherapy. METHODS: We retrospectively analyzed 87 ESCC patients treated initially with radiotherapy. Failure patterns were classified into regional lymph node recurrence only (LN) and primary failure with/without regional lymph node recurrence (PF). Patients received either re-RT or other treatments (non-re-RT group). Baseline covariates were balanced by a propensity score model. Overall survival (OS) and toxicities were assessed as outcomes. RESULTS: The median follow-up time was 87 months. Thirty-nine patients received re-RT. Failure pattern and re-RT were independent prognostic factors for OS (P = 0.040 and 0.015) by Cox multivariate analysis. Re-RT with concomitant chemotherapy showed no survival benefit over re-RT alone (P = 0.70). No differences in characteristics were found between the groups by Chi-square tests after propensity score matching. The Cox model showed that failure pattern and re-RT were prognostic factors with hazard ratios (HR) of 0.319 (P = 0.025) and 0.375 (P = 0.002), respectively, in the matched cohort. Significant differences in OS were observed according to failure pattern (P = 0.004) and re-RT (P < 0.001). In the re-RT and non-re-RT groups, 9.09% and 3.03% of patients experienced tracheoesophageal fistulas, and 15.15% and 3.03% of patients developed pericardial/pleural effusion, respectively (P > 0.05). The incidence of radiation pneumonitis was higher in the re-RT group (24.24% vs. 6.06%, P = 0.039), but no cases of pneumonia-related death occurred. CONCLUSIONS: Re-RT improved long-term survival in patients with locoregional recurrent ESCC. Despite a high incidence of radiation pneumonitis, toxicities were tolerable.

[Comparison of two means for evaluation of apical microleakage].

PURPOSE: To compare the consistency of two means of evaluating the apical microleakage. METHODS: Forty-nine extracted single-rooted human teeth were divided into 3 experimental groups of 15 teeth each, in addition to a positive and negative control group of 2 teeth each. The teeth were instrumented, then obturated using lateral condensation and one of three endodontic sealers: AH Plus(group A), Cortisomol(group B) and zinc oxide eugenol(group C). The apical microleakage was measured by transparent tooth technique or dye dissolution each. SPSS 12.0 software package was used for One-way ANOVA and Kruslal-Wallis test. RESULTS: The two methods both showed that the microleakage in group A was significantly less (P<0.05) than that in group B and C. There was no significant difference between group B and C(P>0.05). CONCLUSION: Based on the dye penetration method, there is some consistency between the transparent tooth technique and dye dissolution method for evaluating apical microleakage.

[In vitro evaluation of correlation between the size of apical foramen and the accuracy of root ZX].

OBJECTIVE: The study was designed to investigate the relationship between the accuracy of Root ZX and the size of apical foramen, when the apical constrictions were intact or not. Methods Lengths were taken when the needle reached the '0.5' mark and 'APEX' mark on the Root ZX. The electronic apex locator (EAL)-measured canal working length (L2) and EAL-measured canal length (L1) were then compared with the actual canal working length (L') and actual canal length (L). Besides, the areas of apical foramens CS) were measured when the apical constriction were intact or not. Then the measurement deviations and the areas of apical foramens were analyzed by linear correlation and linear regression using the software SPSS 12.0. Statistical significance was considered at P < 0.05. RESULTS: There were no significantly correlations between the area of apical foramen and the accuracy of Root ZX if the apical constriction was intact (P > 0.05). However, the accuracy of Root ZX and the size of apical foramen had significant negative correlation when the apical constriction was destroyed (P < 0.001). Then the linear regression was completed, and the linear regression equation was deltaL2 = -0.623 + 6.5965, so the critical area of the apical foramen was 0.135 mm2 if the tolerant error was set at 0.5 mm according to the statistic control. CONCLUSION: The size of apical foramen has little effect on the accuracy of Root ZX if the apical constriction is intact. However the measurements of Root ZX should be used carefully when the apical constriction was destroyed.

[A holographic plate silver film-preparation, morphology and SERS activity].

A new method for preparing SERS-active substrate was reported. After being exposed, developed and fixed, the commercially available holographic plate can be used to generate attractive SERS-active silver surface. The obtained silver film was characterized by UV-Vis spectroscopy and scanning electron microscope (SEM) observation. The absorption spectrum locates at around 420 nm with a narrow half-width due to the surface plasmon resonance, which implies that there are silver particles on the prepared substrate with uniform sizes. And the silver particles distribute uniformly anywhere on the holographic plate with a diameter of about 100 nm by SEM observation. Furthermore, the measurements of the SERS spectrum of crystal violet indicate that such substrate has the features of satisfactory reproducibility, long term stability and high SERS activity. The prepared silver film keeps high SERS activity even if it was stored for several months in the air at room temperature.