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Purpose To explore the findings and diagnostic values of apparent diffusion coefficient (ADC) and diffusion weighted image (DWI) of the portal venous tumor thrombus (PVTT) caused by hepatic carcinoma.Materials and Methods Thirty-one patients with hepatic carcinoma (43 lesions) with 63 PVTT in the main branches and trunks diagnosed by clinical and MRI were enrolled. All patients underwent conventional MRI (cMRI) imaging, DWI and ADC imaging, the features of cMRI, DWI and ADC were observed, the relevance of ADC values between the hepatic carcinoma lesion and PVTT were analyzed.Results Among the total 43 lesions, DWI image showed low signal, iso-signal and high signal in 1, 4 and 38 lesions, respectively; and ADC image showed low signal, iso-signal and high signal in 36, 5 and 2 lesions, respectively. In the total 63 PVTT, DWI showed low signal, iso-signal and high signal in 4, 7 and 52 lesions, respectively;while their ADC images showed low signal, iso-signal and high signal in 54, 6 and 3 branches, respectively. There was good consistency for the results of two observers on the findings of ADC of tumor lesions (Kappa=0.8334,P<0.05), and a moderate consistency on that of PVTT (Kappa=0.5215,P<0.05). The average ADC value of tumor lesion and PVTT was (1.127±0.268)×10-3 mm2/s and (1.021±0.363)×10-3 mm2/s, respectively; there was a correlation of the mean values of ADC between tumor lesion and PVTT (r=0.246,P<0.05). Conclusion The features such as low signal and low value on ADC image and high signal on DWI obtain a certain clinical application value for qualitative diagnoses of PVTT.
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<p><b>OBJECTIVE</b>To investigate the origin and the recombinant model of H7N9 virus prevailing in China by sequence analysis.</p><p><b>METHODS</b>The sequences of H7N9 virus were collected and analyzed with the software BLAST and MEGA 5.0. The phylogenetic trees were constructed after multiple sequences alignment. The homologous sequences of H7N9 segments were determined and the model was inferred according to the origin of H7N9 segments.</p><p><b>RESULTS</b>The most relevant sequences of HA, NA, NS and PB2 segments were located at one branch of the phylogenetic tree, while the closest relevant sequences of PB1, PA, NP and MP contained two H9N2 virus origins. According to the analysis of sequence origin, H7N9 viruses might be divided into 5 genotypes: namely A, B, A/Shanghai/1/2013-H7N9, A/Pigeon/Shanghai/S1069-H7N9 and A/Zhejiang/HZ1/2013-H7N9, and the genotype A consisted of A1 and A2 subtypes.</p><p><b>CONCLUSION</b>The prevailing H7N9 virus might be derived from 5 different viruses after 4 times of recombination, which resulted in the two major types of A and B. The subtypes of A1 and A2 were two different derivatives from one reassortant. The A/Pigeon/Shanghai/S1069-H7N9 strain might be the recombinant of type A H7N9 virus with a local H9N2 virus during the H7N9 epidemics. The A/Zhejiang/HZ1/2013-H7N9 strain could be the re-arrangement of subtype A2 with type B H7N9 virus.</p>