Dynamic enhanced CT evaluation of solitary pulmonary nodules / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the value of dynamic enhanced-CT in differential diagnosis of solitary pulmonary nodules.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

Dual-phase contrast-enhancement multislice computed tomography imaging in assessment of acute myocardial infarction-reperfusion injury / 上海第二医科大学学报

Objective To explore the value of dual-phase contrast-enhancement multislice computed tomography (MSCT) in the assessment of acute myocardial infarction volume and perfusion in porcine models. Methods The distal left anterior descending coronary arteries of 5 pigs were balloon-occluded for 90 min and followed by reperfusion. MSCT was performed 1 min (early phase) and 5 min (delayed phase) after administration bolus of 100 mL of iodinated contrast material 30 min after reperfusion. On the same day, hearts were excised, sectioned in 8 mm short-axis slices, and stained with TTC. Infarction volume was defined as the sum of the hyper-enhanced area and surrounding hypo-enhanced area in all slices on delay enhanced phase of MSCT and the TTC-negative area on TTC staining slices. Infarction volume was expressed as percentage of total slice volume. Results Acute infarction detected by MSCT was characterized by early myocardial perfasion defects in the early phase of the contrast bolus (early defects) with surrounding residual defects and late enhancement observed in the late phase. Mean CT attenuation value of early defects was significantly different from CT attenuation value of remote myocardium [(213±55)HU vs (304±30)HU](P < 0.05), CT attenuation values of residual defects and late enhancement were also significantly different from those of remote myocardium [(360±75) HU vs (90±37) HU and (152±23) HU vs (190±37) HU, repectively](P < 0.01, P < 0.05). The mean infarction volume was (8.9± 1.0)% on MSCT and (9.2±1.4)% on TTC pathology images. The infarction volume assessed by MSCT compared well with TTC staining slices. Conclusion Acute reperfused myocardial infarction zone has specific enhancement pattens different to remote normal zone on dual phase MDCT, which is in good agreement with in vivo Trc pathology in the assessment of acute reperfused myocardial infarction shortly offer reperfusion.

Strong influences of polymerization temperature on ethylene/1-hexene copolymerization catalyzed by (2-PhInd)(2)ZrCl(2)/methyl aluminoxane / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

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.