Prediction of pathologic stage in non-small cell lung cancer using machine learning algorithm based on CT image feature analysis.

PURPOSE: To explore imaging biomarkers that can be used for diagnosis and prediction of pathologic stage in non-small cell lung cancer (NSCLC) using multiple machine learning algorithms based on CT image feature analysis. METHODS: Patients with stage IA to IV NSCLC were included, and the whole dataset was divided into training and testing sets and an external validation set. To tackle imbalanced datasets in NSCLC, we generated a new dataset and achieved equilibrium of class distribution by using SMOTE algorithm. The datasets were randomly split up into a training/testing set. We calculated the importance value of CT image features by means of mean decrease gini impurity generated by random forest algorithm and selected optimal features according to feature importance (mean decrease gini impurity > 0.005). The performance of prediction model in training and testing sets were evaluated from the perspectives of classification accuracy, average precision (AP) score and precision-recall curve. The predictive accuracy of the model was externally validated using lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) samples from TCGA database. RESULTS: The prediction model that incorporated nine image features exhibited a high classification accuracy, precision and recall scores in the training and testing sets. In the external validation, the predictive accuracy of the model in LUAD outperformed that in LUSC. CONCLUSIONS: The pathologic stage of patients with NSCLC can be accurately predicted based on CT image features, especially for LUAD. Our findings extend the application of machine learning algorithms in CT image feature prediction for pathologic staging and identify potential imaging biomarkers that can be used for diagnosis of pathologic stage in NSCLC patients.

[Correlation between minimal apparent diffusion coefficient and expression of Ki-67 in glioma].

OBJECTIVE: To explore the correlation between minimal apparent diffusion coefficient (minADC) and expression of Ki-67 in glioma. METHODS: Findings from 78 patients with pathologically proven gliomas (grade II:n = 28, grade III: n = 21, grade IV: n = 29) were analyzed retrospectively. The minADC value of each tumor was determined on ADC maps. The Ki-67 labeling index (LI) of surgical specimen was measured. The results were analyzed statistically. RESULTS: The mean value of minADC for gliomas of grade II ((1.23 ± 0.23)×10(-3) mm(2/s)) was higher than that of grade III ((0.92 ± 0.20)×10(-3) mm(2/s)) (P < 0.01) and than that of grade IV ((0.80 ± 0.16)×10(-3) mm(2)/s) (P < 0.01). But no significant difference existed between the mean value of minADC of grade III and that of grade IV (P = 0.069). There were significant negative correlations between minADC and different tumor grades (r = -0.678, P < 0.01). The mean value of Ki-67 LI showed significant differences between grade II (3.6% ± 2.3%), grade III (14.8% ± 7.3%) and grade IV (29.9% ± 13.1%) (P < 0.01). There were significant positive correlations between Ki-67 LI and different tumor grades (r = 0.835, P < 0.01). And a negative correlation existed between minADC and Ki-67 LI (r = -0.556, P < 0.01). CONCLUSION: The value of minADC is useful for predicting glioma grade.

[Dynamic enhanced CT evaluation of solitary pulmonary nodules].

OBJECTIVE: To evaluate the value of dynamic enhanced-CT in differential diagnosis of solitary pulmonary nodules. METHODS: Sixty-three solitary pulmonary nodules were evaluated by dynamic enhanced multi-slice CT. Images were obtained before and at 20 s, 30 s, 45 s, 60 s, 75 s, 90 s, 120 s, 180 s, 300 s, 540 s, 720 s, 900 s and 1200 s after the injection of contrast media. All lesion enhanced parameters and morphological features were recorded. The differences between benign and malignant nodules were analyzed. The diagnostic sensitivity and specificity of solitary pulmonary nodules were evaluated by receiver operator characteristic analysis. RESULTS: CT enhancement value at 120 s [(29.5 ± 30.2) HU vs. (32.5 ± 14.7) HU, P = 0.023], washout at 20 min [(36.5 ± 24.6) HU vs. (15.6 ± 16.6) HU, P = 0.044], washout ratio at 20 min [(36.5 ± 24.6)% vs. (17.8 ± 14.5)%, P = 0.006], slope of washout at 20 min [(0.006 ± 0.005)%/s vs. (0.002 ± 0.0016)%/s, P = 0.001], type II (24/42 vs. 4/21, P = 0.004) and III (5/42 vs. 9/21, P = 0.005) curves were significantly different between benign and malignant nodules. Using the above mentioned parameters, the results of receiver operator characteristic analysis had a sensitivity of 64.3% and specificity of 84.2% for identification of malignant tumors. The morphological features including round-like, triangle-like, multi-angle, spiculation, light lobulation, the degree of edge (sharp, clear, blur), vessel convergence sign, vacuole sign, airing of bronchi, cut-off of the bronchi and depression of pleura were significantly different between benign and malignant nodules. The results of ROC analysis showed that the above mentioned morphological features had a sensitivity of 92.9% and specificity of 100% for differentiating malignant tumors from benign nodules. The results of ROC analysis showed that combination of morphological features and dynamic enhancement parameters had a sensitivity of 95.2% and specificity of 100% for identification of malignant tumors. CONCLUSIONS: Dynamic enhanced CT images can evaluate morphological and enhancement features of solitary pulmonary nodules. Combination of morphological features and enhancement characteristics can improve the accuracy of diagnosis.

Use of relative CT values to evaluate the invasiveness of pulmonary subsolid nodules in patients with emphysema.

BACKGROUND: Lung cancer is a major cause of death, and adenocarcinoma is the most common histologic subtype. Precise diagnosis and treatment of invasive adenocarcinoma (IAC) can substantially improve the survival of patients. However, early-stage adenocarcinomas frequently appear as subsolid nodules (SSN) on computed tomography (CT), and the optimal cut-off CT value for differentiating the invasiveness of SSNs in emphysematous patients is unclear. METHODS: High-resolution CT targeted scans of 187 pulmonary SSNs in 175 patients with emphysema as confirmed by surgery and histology were retrospectively reviewed. The mean CT value, the relative CT (rCT) values of 1 (nodule CT value - lung CT value), and 2 (nodule CT value/lung CT value), and the size of the SSNs were measured and calculated. The differentiating performance of the CT values between pre-invasive and invasive tumors was evaluated using a receiver operating characteristic (ROC) curve. RESULTS: Significant differences were found in the rCT values of 1 and 2 among pure ground-glass nodules (GGNs) with different levels of invasiveness, in the rCT values of 1 and 2 for the ground-glass component (GGC) and the mean CT value of the solid component (SC) of part-solid nodules (PSNs) between minimally invasive adenocarcinoma (MIA) and IAC (all P<<0.05). The size was significantly different among pure GGNs with different invasiveness (P<0.05). The cut-off rCT values of 1, 2 and nodule size for differentiating between pre-invasive and invasive pure GGNs were 293.82 [sensitivity 58.0%, specificity 94.7%; area under the curve (AUC) 0.783], 0.68 (sensitivity 89.5%, specificity 58.0%, AUC 0.742) and 1.10 cm (sensitivity 74.0%, specificity 79.0%, AUC 0.796), respectively. The AUCs of combining rCT values 1 and 2 with the size of nodule were 0.795 (sensitivity 62.5%, specificity 89.5%) and 0.845 (sensitivity 71.6%, specificity 89.5%) respectively. There were no significant differences in the mean CT values between pure GGNs with different levels of invasiveness and between the GGC of PSNs of MIA and IAC. CONCLUSIONS: In patients with emphysema, the rCT values are more useful than the mean CT values for differentiating between SSNs with different invasiveness and can be valuable for patient management.

Dependence of radiomic features on pixel size affects the diagnostic performance of radiomic signature for the invasiveness of pulmonary ground-glass nodule.

OBJECTIVE: To investigate the effect of reducing pixel size on the consistency of radiomic features and the diagnostic performance of the downstream radiomic signatures for the invasiveness for pulmonary ground-glass nodules (GGNs) on CTs. METHODS: We retrospectively collected the clinical data of 182 patients with GGNs on high resolution CT (HRCT). The CT images of different pixel sizes (0.8mm, 0.4mm, 0.18 mm) were obtained by reconstructing the single HRCT scan using three combinations of field of view and matrix size. For each pixel size setting, radiomic features were extracted for all GGNs and radiomic signatures for the invasiveness of GGNs were built through two modeling pipelines for comparison. RESULTS: The study finally extracted 788 radiomic features. 87% radiomic features demonstrated inter pixel size variation. By either modeling pipeline, the radiomic signature under small pixel size performed significantly better than those under middle or large pixel sizes in predicting the invasiveness of GGNs (p's value <0.05 by Delong test). With the independent modeling pipeline, the three pixel size bounded radiomic signatures shared almost no common features. CONCLUSIONS: Reducing pixel size could cause inconsistency in most radiomic features and improve the diagnostic performance of the downstream radiomic signatures. Particularly, super HRCTs with small pixel size resulted in more accurate radiomic signatures for the invasiveness of GGNs. ADVANCES IN KNOWLEDGE: The dependence of radiomic features on pixel size will affect the performance of the downstream radiomic signatures. The future radiomic studies should consider this effect of pixel size.

Contrast-enhanced CT longitudinal tail sign as a marker of positive resection margins in adenoid cystic carcinoma of the central airway.

BACKGROUND: Due to submucosal infiltration's biological nature along the airway, adenoid cystic carcinoma (ACC) frequently leaves positive surgical margins. This study evaluated the clinicopathologic, and computed tomography (CT) features for predicting surgical margin status in central airway ACC. METHODS: We retrospectively analyzed the files of 71 patients with ACC of the central airway proven by histopathology and surgery who had presented between January 2010 and December 2018. All patients were classified into positive and negative surgical margin groups according to margin status. Univariate analysis and multivariable logistic regression models were then performed to compare demography, histopathology, and CT characteristics between ACC patients with positive and negative margins. RESULTS: After surgical resection, 59 (83.1%) patients had positive margins, and 12 (16.9%) had negative margins. The contrast-enhanced CT (CECT) longitudinal tail sign (LTS) was identified in 55 of 59 (93.2%) patients with positive margins and was the only feature that had a significant association with positive margins (odds ratio 41.250, 95% CI: 7.886-215.767; P<0.001). Moreover, positive margins in upper or/and lower directions were associated with the LTS in corresponding directions (P<0.001). CONCLUSIONS: Most central airway ACC patients exhibited positive margins following surgery. The appearance of the LTS on CECT was significantly associated with positive margins and could help preoperatively predict the submucosal invasion of ACC.

Efficacy and safety of a new disposable percutaneous positioning device invented to facilitate the precision of percutaneous core needle lung biopsies: a prospective, open and randomized controlled study.

BACKGROUND: A new disposable percutaneous positioning device was developed which permits adjustment of the fixing puncture angle while performing a percutaneous core needle lung biopsy (CNLB). The aim of the study was to explore the positioning accuracy and clinical safety of the new device during CT-guided percutaneous CNLB. METHODS: A prospective, open and randomized controlled study with two parallel groups was conducted on 150 patients with pulmonary nodules between July 1, 2018 and June 30, 2019 including 101 males and 49 females who were divided (allocation ratio: 1:1) into a standard CNLB group without the percutaneous positioning device (control, n=75) and a new percutaneous positioning device group combined with CNLB (experimental, n=75). The efficacy was determined by the success rate of reaching the target location on the first percutaneous attempt, the number of CT scans performed and the time required for successful puncture positioning. Safety evaluations included complications related to percutaneous surgery and the new positioning device. RESULTS: The success rate of reaching the target location on the first percutaneous attempt in the experimental group was significantly higher than in the control group [96.0% (72/75) vs. 42.7% (32/75), P<0.001]. Patients in the experimental group received 3.05±0.28 times CT scans on average for successful percutaneous positioning, which was significantly lower than for the control group (3.95±1.03) (P<0.001). The time required to complete the percutaneous positioning was significantly lower in the experimental group compared to the control group (8.73±3.11 vs. 12.79±4.55 min, P<0.001). There was no significant difference in percutaneous-related complications between the two groups [48.0% (36/75) vs. 61.3% (46/75), P=0.101], except that the bleeding rate in the experimental group was lower than in the control group [26.7% (20/75) vs. 46.7% (35/75), P=0.032]. CONCLUSIONS: The use of the optimized percutaneous technology with the new positioning device significantly improved the accuracy and precision of percutaneous lung biopsies. TRIAL REGISTRATION: ChiCTR-INR-17010322.

Multicenter, prospective, observational study of a novel technique for preoperative pulmonary nodule localization.

OBJECTIVES: Minimally invasive surgery provides an ideal method for pathologic diagnosis and curative intent of small pulmonary nodules (SPNs); however, the main problem with thoracoscopic resection is the difficulty in locating the nodules. The goal of this study was to determine the safety and feasibility of a new localization technique tailored for SPNs. METHODS: A computed tomography (CT)-guided technique, which has a tri-colored suture and claw with 4 fishhook-shaped hooks, was designed to localize SPN preoperatively. Then a multicenter, prospective study was conducted to evaluate the safety and feasibility of this device. The primary endpoints included safety (asymptomatic/symptomatic pneumothorax or parenchymal hemorrhage, and unanticipated adverse effects) and success rate (precise placement and device fracture, displacement, or dislodgement). The secondary endpoints included feasibility (duration of the localization procedure and device fracture or fault) and patient comfort (pain). RESULTS: A total of 90 SPNs were localized from 80 patients. Overall, no symptomatic complications requiring medical intervention, with the exception of asymptomatic pneumothorax (n = 7 [7.8%]) and lung hemorrhages (n = 5 [5.6%]), were observed. The device was successfully placed without dislodgment or movement in 87 of 90 lesions (96.7%). The median nodule size was 0.70 cm (range, 0.30-1.0 cm). The median duration of the procedure was 15 minutes (range, 7-36 minutes). No patient complained of notable pain during or after the procedure. CONCLUSIONS: This new device for SPNs is safe, and has a high success rate, feasibility and good tolerance.

Water-assisted atom transfer radical polymerization of N-isopropylacrylamide: nature of solvent and temperature.

We demonstrate here via the atom transfer radical polymerization (ATRP) of N-isopropylacrylamide (NIPAM) at low temperature that the negative function of water in aqueous ATRP is significantly suppressed. By the addition of a small amount of water in a water-miscible organic solvent and maintaining low polymerization temperature, the ATRP of NIPAM is relatively fast and well controlled. We observed that the rate of the polymerization in pure organic solvent at a monomer concentration of 20 wt % is slow, and relatively low conversions were obtained. The low conversion of PNIPAM in pure alcoholic media (such as methanol, ethanol, and n-propanol) is attributed to the poor solubility of the resulting low molecular weight polymer in such solvents. The consequence is that the PNIPAM chains are aggregated, resulting in the inaccessibility of the embedded halide atom of the polymer chain ends by the copper catalyst. As expected, the ATRP of NIPAM in pure water was found to be fast and uncontrolled. These results have therefore prompted us to study the ATRP of NIPAM in aqueous-organic mixtures. Room temperature polymerization of NIPAM in mixed aqueous-organic solvent mixtures (organic:water = 4:1 or 3:1) revealed to be fast and uncontrolled. However, when the NIPAM polymerization was conducted at low temperature (0 degrees C) in such solvent systems, the polymerization turned out to be well-controlled as the molar masses progress linearly with conversion, and pseudo-first-order kinetic plots were obtained. Furthermore, monomodal GPC traces and narrow molecular weight distributions were obtained in all aqueous-organic solvent systems. Chain extension for aqueous ATRP of NIPAM revealed to proceed well at low temperature as compared to room temperature. Furthermore, we observe that the rates of the polymerization of NIPAM in different aqueous-organic mixtures follow the trend of polarity in the case of the polar aprotic solvents. However, in the case of polar protic solvent (such as methanol, ethanol, 1-propanol, and 2-propanol), the rate of the polymerization was found to increase with increasing solubility of the PNIPAM from methanol to 2-propanol.

[Values in preoperative assessment of occlusion and intra-operative guidance of 64 row spiral CT in percutaneous coronary intervention for chronic coronary occlusion].

OBJECTIVE: To instigate the values of 64 row spiral CT in pre-operative assessment of the occlusion and intra-operative guidance in percutaneous coronary intervention for chronic total occlusion (CTO) in coronary heart disease. METHODS: Fifteen coronary disease patients planned to receive percutaneous coronary intervention underwent 64-row spiral CT-coronary angiography and coronary angiography (CAG). The diagnostic effects of these 2 techniques were compared. RESULTS: Seventeen CTO lesions were confirmed. MSCT succeeded to show the lengths of the 17 CTO lesions with a calcification identification rate of 76.4%, significantly higher than that of the CAG (41.5%). By cross-section examination, MSCT succeeded to detect the occlusion degree of the calcified lesions, and showed that 3 CTO lesions were occluded at a rate < 50%, and 10 lesions at a rate > or = 50%. Twelve complete occlusion lesions in 11 patients underwent PCT, success was seen in 6 of which and failure in the other 6. Univariate analysis showed that the length of lesion, branching at the proximal site, formation of bridging lateral branch, form of occlusion end, and calcification were all not significantly related to the success or failure of intervention. The percentage of the calcification area > or = 50% in the intervention failure group was 83.3%, significantly higher than that in the intervention success group (16.7%, P = 0.05). 3-D images of coronary artery could be obtained by MSCT to show all the complete occlusive lesions. CONCLUSION: 64-MSCT demonstrates a remarkable ability to identify silicified lesions, can re-establish 3-D images of coronary artery, and effectively guide the intervention therapy.

High-resolution Computed Tomography Features Distinguishing Benign and Malignant Lesions Manifesting as Persistent Solitary Subsolid Nodules.

INTRODUCTION: We retrospectively investigated the high-resolution computed tomography features that distinguish benign lesions (BLs) from malignant lesions (MLs) appearing as persistent solitary subsolid nodules (SSNs). MATERIALS AND METHODS: In 2015, the data from patients treated in our department with persistent solitary SSNs 5 to 30 mm in size were analyzed retrospectively. The demographic data and HRCT findings were analyzed and compared between those with BLs and MLs. RESULTS: Of the 1934 SSNs, 94 were BLs and 1840 were MLs. One half of the MLs (920 SSNs) were randomly selected and analyzed. The BLs were classified into 2 subgroups: 28 pure ground-glass nodules (pGGNs) and 66 part-solid nodules (PSNs). After matching in each group, 56 pGGNs and 132 PSNs in the ML group were selected. In the pGGN subgroup, multivariate analysis found that a well-defined border (odds ratio [OR], 4.320; 95% confidence interval [CI], 1.534-12.168; P = .006; area under the curve, 0.705; 95% CI, 0.583-0.828; P = .002) and a higher average CT value (OR, 1.007; 95% CI, 1.001-1.013; P = .026; area under the curve, 0.715; 95% CI, 0.599-0.831; P = .001) favored the diagnosis of malignancy. In the PSN subgroup, multivariate analysis revealed that a larger size (OR, 1.084; 95% CI, 1.015-1.158; P = .016), a well-defined border (OR, 3.447; 95% CI, 1.675-7.094; P = .001), and a spiculated margin (OR, 2.735; 95% CI, 1.359-5.504; P = .005) favored the diagnosis of malignancy. CONCLUSION: In pGGNs, a well-defined lesion border and a larger average CT value can be valuable discriminators to distinguish between MLs and BLs. In PSNs, a larger size, well-defined border, and spiculated margin had greater predictive value for malignancy.

Abnormal Gray Matter Structural Networks in Idiopathic Normal Pressure Hydrocephalus.

Purpose: Idiopathic normal pressure hydrocephalus (iNPH) is known as a treatable form of dementia. Network analysis is emerging as a useful method to study neurological disorder diseases. No study has examined changes of structural brain networks of iNPH patients. We aimed to investigate alterations in the gray matter (GM) structural network of iNPH patients compared with normal elderly volunteers. Materials and Methods: Structural networks were reconstructed using covariance between regional GM volumes extracted from three-dimensional T1-weighted images of 29 possible iNPH patients and 30 demographically similar normal-control (NC) participants and compared with each other. Results: Global network modularity was significantly larger in the iNPH network (P < 0.05). Global network measures were not significantly different between the two networks (P > 0.05). Regional network analysis demonstrated eight nodes with significantly decreased betweenness located in the bilateral frontal, right temporal, right insula and right posterior cingulate regions, whereas only the left anterior cingulate was detected with significantly larger betweenness. The hubs of the iNPH network were mostly located in temporal areas and the limbic lobe, those of the NC network were mainly located in frontal areas. Conclusions: Network analysis was a promising method to study iNPH. Increased network modularity of the iNPH group was detected here, and modularity analysis should be paid much attention to explore the biomarker to select shunting-responsive patients.

Community-based lung cancer screening with low-dose CT in China: Results of the baseline screening.

OBJECTIVES: To investigate whether low-dose computed tomography (LDCT) screening is capable of enhancing the detection rate of early-stage lung cancer in high-risk population of China with both smoking and non-smoking related factors. METHODS: From 2013-2014, eligible participants with high-risk factors of lung cancer were randomly assigned to a screening group or a control group with questionnaire inquiries. Any non-calcified nodules or masses with longest diameters of ≥4 mm identified on LDCT images were considered as positive. RESULTS: A total of 6717 eligible participants were randomly enrolled to a study group (3550 to LDCT screening and 3167 to standard care). 3512 participants (98.9%) underwent LDCT screening, and 3145 participants (99.3%) received questionnaire inquiries. A positive screening result was observed in 804 participants (22.9%). In the two-year follow-up period, lung cancer was detected in 51 participants (1.5%) in the LDCT group versus 10 (0.3%) in the control group (stage I: 48 vs 2; stage II to IV or limited stage: 3 vs 8), respectively. Early-stage lung cancer was found in 94.1% vs 20%, respectively. CONCLUSIONS: Compared to usual care, LDCT led to a 74.1% increase in detecting early-stage lung cancer. This study provides insights about the non-smoking related risk factors of lung cancer in the Chinese population.

"Living" Polymerization of Ethylene and 1-Hexene Using Novel Binuclear Pd⁻Diimine Catalysts.

We report the synthesis of two novel binuclear Pd⁻diimine catalysts and their unique behaviors in initiating "living" polymerization of ethylene and 1-hexene. These two binuclear catalysts, [(N^N)Pd(CH2)3C(O)O(CH2)mO(O)C(CH2)3Pd(N^N)](SbF6)2 (3a: m = 4, 3b: m = 6) (N^N≡ArN=C(Me)⁻(Me)C=NAr, Ar≡2,6⁻(iPr)2C6H3), were synthesized by simply reacting [(N^N)Pd(CH3)(N≡CMe)]SbF6 (1) with diacrylates, 1,4-butanediol diacrylate and 1,6-hexanediol diacrylate, respectively. Their unique binuclear structure with two identical Pd⁻diimine acrylate chelates covalently linked together through an ester linkage was confirmed by NMR and single crystal XRD measurements. Ethylene "living" polymerizations were carried out at 5 °C and under ethylene pressure of 400 and 100 psi, respectively, with the binuclear catalysts, along with a mononuclear chelate catalyst, [(N^N)Pd(CH2)3C(O)OMe]SbF6 (2), for comparison. All the polyethylenes produced with both binuclear catalysts show bimodal molecular weight distribution with the number-average molecular weight of the higher molecular weight portion being approximately twice that of the lower molecular weight portion. The results demonstrate the presence of monofunctional chain growing species resembling catalyst 2, in addition to the expected bifunctional species leading to bifunctional "living" polymerization, in the polymerization systems. Both types of chain growing species exhibit "living" characteristics under the studied conditions, leading to the simultaneous linear increase of molecular weight in both portions. However, when applied for the "living" polymerization of 1-hexene, the binuclear catalyst 3a leads to polymers with only monomodal molecular weight distribution, indicating the sole presence of monofunctional chain growing species. These two binuclear catalysts are the first Pd⁻diimine catalysts capable of initiating bifunctional ethylene "living" polymerization.

Efficacy of computed tomography features in predicting stage III thymic tumors.

Accurate assessment of the invasion of intrathoracic structures by stage III thymic tumors assists their appropriate management. The present study aimed to evaluate the efficacy of computed tomography (CT) features for the prediction of stage III thymoma invasion. The pre-operative CT images of 66 patients with confirmed stage III thymic tumors were reviewed retrospectively. The CT features of invasion into the mediastinal pleura, lungs, pericardium and great vessels were analyzed, and their sensitivity, specificity, positive predictive value (PPV), negative predictive value and accuracy were calculated. For mediastinal pleural and pericardial invasion, an absence of space between the tumor and the mediastinal pleura/pericardium with mediastinal pleural/pericardial thickening and pleural/pericardial effusion exhibited a specificity and PPV of 100%, respectively. For lung invasion, a multi-lobular tumor convex to the lung with adjacent lung abnormalities exhibited a specificity and PPV of 91.2 and 81.3%, respectively. For vessel invasion, the specificity and PPV were each 100% for tumors abutting ≥50% of the vessel circumference, and for tumor oppression, deformation and occlusion of the vessel. In conclusion, recognition of the appropriate CT features can serve as a guide to invasion by stage III thymic tumors, and can facilitate the selection of appropriate pre-operative treatment.

Tumor invasiveness defined by IASLC/ATS/ERS classification of ground-glass nodules can be predicted by quantitative CT parameters.

BACKGROUND: To investigate the potential value of CT parameters to differentiate ground-glass nodules between noninvasive adenocarcinoma and invasive pulmonary adenocarcinoma (IPA) as defined by IASLC/ATS/ERS classification. METHODS: We retrospectively reviewed 211 patients with pathologically proved stage 0-IA lung adenocarcinoma which appeared as subsolid nodules, from January 2012 to January 2013 including 137 pure ground glass nodules (pGGNs) and 74 part-solid nodules (PSNs). Pathological data was classified under the 2011 IASLC/ATS/ERS classification. Both quantitative and qualitative CT parameters were used to determine the tumor invasiveness between noninvasive adenocarcinomas and IPAs. RESULTS: There were 154 noninvasive adenocarcinomas and 57 IPAs. In pGGNs, CT size and area, one-dimensional mean CT value and bubble lucency were significantly different between noninvasive adenocarcinomas and IPAs on univariate analysis. Multivariate regression and ROC analysis revealed that CT size and one-dimensional mean CT value were predictive of noninvasive adenocarcinomas compared to IPAs. Optimal cutoff value was 13.60 mm (sensitivity, 75.0%; specificity, 99.6%), and -583.60 HU (sensitivity, 68.8%; specificity, 66.9%). In PSNs, there were significant differences in CT size and area, solid component area, solid proportion, one-dimensional mean and maximum CT value, three-dimensional (3D) mean CT value between noninvasive adenocarcinomas and IPAs on univariate analysis. Multivariate and ROC analysis showed that CT size and 3D mean CT value were significantly differentiators. Optimal cutoff value was 19.64 mm (sensitivity, 53.7%; specificity, 93.9%), -571.63 HU (sensitivity, 85.4%; specificity, 75.8%). CONCLUSIONS: For pGGNs, CT size and one-dimensional mean CT value are determinants for tumor invasiveness. For PSNs, tumor invasiveness can be predicted by CT size and 3D mean CT value.

CT staging and preoperative assessment of resectability for thymic epithelial tumors.

BACKGROUND: The aim of this study was to determine the computed tomography (CT) features potentially helpful for accurate staging and predicting resectability of thymic epithelial tumors (TET). METHODS: One hundred and thirty-eight consecutive TET patients undergoing surgical resection from April 2010 to November 2011 were prospectively entered into a database. All patients were staged according to the Masaoka-Koga staging system. The relationship between CT features with tumor staging and complete resection was reviewed after surgery. RESULTS: Surgico-pathological staging was stage I in 63, stage II in 32, stage III in 32, and stage IV in 11 patients. Preoperative CT staging was highly consistent with postoperative surgico-pathological staging (Kappa =0.525). Tumor shape, contour, enhancement, with or without invasion of the adjacent structures (mediastinal fat, mediastinal pleura, lung, pericardium, mediastinal vessels, phrenic nerve), and presence of pleural, pericardial effusionor intrapulmonary metastasis were correlated with Masaoka-Koga staging (P<0.05). However, tumor size, internal density or presence of calcification was not associated with staging (P>0.05). Tumor size, presence of calcification and mediastinal lymph node enlargement were not correlated with complete tumor resection (P>0.05). Tumor shape, contour, internal density, enhancement pattern, and invasion of adjacent structures were related to complete resection of the primary tumor in univariate analysis (P<0.05). However, upon multivariate logistic regression, only absence of artery systems invasion was predictive of complete resection (P<0.05). CONCLUSIONS: Clinical staging of TET could be accurately evaluated with CT features including tumor shape, contour, enhancement pattern, with or without invasion of adjacent structures, and presence of pleural, pericardial effusion or intrapulmonary metastasis. Absence of arterial system invasion on CT was the only predictive feature for predicting complete resection of TET.

Strong influences of polymerization temperature on ethylene/1-hexene copolymerization catalyzed by (2-PhInd)(2)ZrCl(2)/methyl aluminoxane.

Ethylene/1-hexene was copolymerized by an unbridged zirconocene, (2-PhInd)(2)ZrCl(2)/MAO (methyl aluminoxane) at 0 degrees C and 50 degrees C respectively. High copolymerization activity and 1-hexene incorporation were observed at 0 degrees C, with the copolymer formed having random sequence distribution and narrow molecular weight distribution. Ethylene polymerization at 50 degrees C showed high activity, but copolymerization at 50 degrees C showed much lower activity, which decreased sharply with increasing 1-hexene concentration in the monomer feed. Copolymer formed at 50 degrees C showed blocky sequence distribution and broad molecular weight distribution. A mechanism model based on ligand rotation hindered by the propagation chain has been proposed to qualitatively explain the observed phenomena.

Clinical significance of a single multi-slice CT assessment in patients with coronary chronic total occlusion lesions prior to revascularization.

Accurate assessment of coronary chronic total occlusion (CTO) lesion is essential to design an appropriate procedural strategy before revascularization. The present study aims to evaluate the significance of a single multislice computed tomography (MSCT) examination in patients with CTO lesion. We retrospectively analyzed the clinical data of 23 CTO lesions in twenty patients underwent computed tomography coronary angiography (CTCA) and SPECT. The CTCA was more powerful and sensitive to determine the CTO lesion length (100% v.s 47.8%) and to identify the length and location of calcification in occluded vessels compared with the coronary angiography (CAG). The LVEF measured by MSCT was comparable to that from the gated SPECT. Myocardial perfusion imaging showed that the location of the early defect region identified by MSCT was corresponded to the nuclide filling defect on the stressed 201thallium-SPECT imaging. The late hyperenhancement on MSCT was presented as incomplete nuclide filling on the 99mTc-MIBI imaging. The results suggested that a single MSCT examination in previous myocardial infarction without revascularization facilitates to provide some valuable information on the nature of the occluded lesion, myocardial perfusion and globe cardiac function, which would be helpful to design appropriate revascularization strategy in these subjects.

Assessment of the feeding arteries by three-dimensional computed tomography angiography prior to multi-arterial infusion chemotherapy for lung cancer.

The aim of this study was to evaluate the efficacy of multi-detector row helical computed tomography (MDCT) angiography in the detection of feeding arteries prior to multi-arterial infusion for lung cancer. A total of 59 consecutive patients (44 males and 15 females; age range, 27-86 years; median age, 62 years) with non-small cell lung cancer underwent MDCT angiography of the thorax prior to multi-arterial infusion for lung cancer. Findings on CT angiograms, including CT scans, maximum intensity projections and three-dimensional volume-rendered images, were used to evaluate the depiction of bronchial and non-bronchial systemic arteries. The results of detecting the feeding arteries for lung cancer by MDCT angiography and conventional angiography were compared. Among the 59 patients treated with multi-arterial infusion chemotherapy, a total of 80 feeding arteries (62 bronchial feeding arteries and 18 non-bronchial systemic arteries) were detected by conventional angiography and/or MDCT angiography. In 56 (70%) feeding arteries (including 44 bronchial feeding arteries and 12 non-bronchial systemic arteries) for lung cancers, concordant findings were observed with the two modalities. In 23 (29%) cases, MDCT angiography could not be used to define feeding arteries, but was used to identify the ostia of these feeding arteries. In one (1/80, 1.3%) case, the CT-defined feeding artery was not selectively catheterized. MDCT angiography of the chest is able to provide an overview for successful catheterization in multi-arterial infusion chemotherapy for lung cancer.