Chronic hepatitis B is a major cause for liver cirrhosis and its complications hepatic decompensation and hepatocellular carcinoma (HCC), resulting in 500,000 to 1.2 million hepatitis B-related deaths annually. 1 Suppression of HBV DNA is a principal goal in treating chronic hepatitis B because this was shown to significantly improve liver histology and to decrease rates of hepatic complications and HCC. 2,3 Patients with chronic hepatitis B should be considered for antiviral treatment when HBV DNA levels are Ͼ2000 IU/mL, serum alanine aminotransferase levels are above the upper limit of normal, and liver histology shows at least moderate necroinflammation or fibrosis. Patients with liver cirrhosis are candidates for antiviral therapy even if alanine aminotransferase levels are normal or if HBV DNA levels are Ͻ2000 IU/mL. Current treatment options are pegylated interferonalfa and nucleoside or nucleotide inhibitors of the HBV polymerase/reverse transcriptase. For treating chronic hepatitis B, five polymerase inhibitors have been approved so far: the nucleoside analogues lamivudine, telbivudine, entecavir, and the nucleotide analogues adefovir dipivoxil and, most recently, tenofovir disoproxil.Entecavir is a potent cyclopentyl guanosine nucleoside inhibitor of the HBV polymerase which was approved for the treatment of patients with both hepatitis B envelope antigen (HBeAg)-positive and HbeAg-negative chronic hepatitis B and compensated liver disease. 4 Compared to lamivudine or adefovir, entecavir has a higher antiviral efficacy and superior resistance profile. 4
1-chlorocyclohexyl-phosphorus dichloride is formed in a Kharasch type chain reaction when 7-rays act on mixtures of phosphorus trichloride and cyclohexene. The G-value is proportional to the reciprocal square root of the dose rate and readies a maximum at 100 °C. The activation energy of the rate determining step PC12C6H10-+PC13 PC12C6H 10C1 + PC12-was found to amount to 6, 7 kcal/mole. At higher temperatures, the yield strongly decreases since another chain reaction predominates which produces cyclohexyl-phosphorus dichloride. The two chains have a common propagation step. 1-chlorocyclohexyl-phosphorus dichloride and cyclohexyl-phosphorus di chloride are also thermally formed at temperatures above about 150 °C.Die Addition von Polyhalogeniden wie CC14 und CBr4 an Olefine unter Bildung von 1.1.1.3-Tetrahalogeniden ist durch die Arbeiten von K h a r a s c h , J e n s e n und U r r y 1 seit langem bekannt. A udi Phos phortrichlorid vermag sich an Doppelbindungen als CI + PC12 anzulagern, wie am Beispiel des Okten-1 gezeigt worden is t2. Zur Auslösung solcher Reak tionen dient die thermische Zersetzung zugefügten Diacetylperoxyds; in manchen Fällen ist auch Licht als Katalysator geeignet. K h a r a s c h et al. formulier ten die Addition der Polyhalogenide an Olefine als radikalische Kettenreaktion mit den Wachstums schritten
Die Analyse des ReaktionsgemischesAls Strahlenquellen dienten 60Co-Präparate von 100 bis 3000 Curie. Die Proben wurden in abge-3 E. J u n g e r m a n n , J. J . M c B r i d e , R. C l u t t e r u . A. M a i s , J.org. Chemistry 27, 606 [1962].
Purpose: To evaluate the effect of different reconstruction kernels on the semi-automated segmentation of liver lesions in MDCT.
Materials and Methods: A total 62 liver lesions were measured by three independent radiologists with the semi-automated segmentation software Oncology-Prototype (Fraunhofer MEVIS, Siemens Healthcare, Germany) using MDCT datasets (3-mm slice thickness, 2-mm increment) reconstructed with standard, soft and detailed kernels (Philips B, A and D). To ensure objective measurements, only lesions with satisfactory initial segmentation were included, and manual correction was not used. The effective diameter and volume were recorded for each lesion. Segmentation in the soft and detailed kernel datasets was performed by copying the initial seed's position from the standard kernel dataset.
Results: The mean effective lesion diameter was 19.9???9.7?mm using the standard kernel. Comparing the three kernels, no significant differences were found. The mean difference was 1?% ??6?% for the standard kernel compared to the soft kernel, 3?% ??13?% for the standard kernel vs. the detailed kernel and 2?% ??9?% for the soft kernel compared to the detailed kernel. The intra-class correlation coefficients were >?0.96 in all cases.
Conclusion: The semi-automated segmentation and volumetry of liver lesions shows reliable measurements regardless of the kernel used for reconstruction of the MDCT dataset.
Key Points:
??Semi-automated segmentation and volumetry of liver lesions is reliable regardless of the kernel used for reconstruction of the MDCT dataset.
??Until today the gold standard for the evaluation of tumor response has been unidimensional manual measurement.
??Volumetric measurements could improve the assessment of tumor growth.
Citation Format:
??Pinto dos Santos D, Kl?ckner R, Wunder K et?al. Effect of Kernels Used for the Reconstruction of MDCT Datasets on the Semi-Automated Segmentation and Volumetry of Liver Lesions. Fortschr R?ntgenstr 2014; 186: 780???784
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