Objective:To explore the value of metagenomic next-generation sequencing (mNGS) in the pathogen diagnosis of liver abscess.Methods:A perspective study was performed in 35 hospitalized patients with liver abscess in Department of Emergency Medicine, Zhongshan Hospital, Fudan University from February 2020 to April 2021. Blood samples and abscess drainage fluid samples were detected by routine microbial culture and mNGS. Patients were divided into two groups according to whether they had septic shock or not. SPSS 25.0 was used for statistical analysis.Results:The overall positive rate of mNGS in blood samples and drainage fluid samples was significantly higher than that of routine microbial culture methods (blood: 67.6% vs. 15.2%, P<0.05; Drainage fluid: 100% vs. 55.2%, P<0.05). In 35 patients with liver abscess, 71.4% of the pathogens were Klebsiella pneumoniae. The sequence number of pathogenic pathogens detected by mNGS in abscess drainage fluid samples of patients in the shock group was significantly higher than that in the non-shock group ( P<0.05). Conclusions:The mNGS can quickly and accurately detect the pathogen of liver abscess, which can provide important etiological diagnostic for clinical treatment.

To assess the normal value of left ventricular twist (LVtw) and examine the changeswith normal aging by 2-dimensional ultrasound speckle-tracking imaging (STI), 121 healthy volunteers were divided into three age groups: a youth group (19-45 y old), a middle-age group (46-64 y old ) and an old-age group (≥65 y old). Basal and apical short-axis images of left ventricular were ac- quired to analyse LV rotation (LVrot) and LVrot velocity. LVtw and LVtw velocity was defined as apical LVrot and LVrot velocity relative to the base. Peak twist (Ptw), twist at aortic valve closure (AVCtw), twist at mitral valve opening (MVOtw), untwisting rate (UntwR), half time of untwisting (HTU), peak twist velocity (PTV), time to peak twist velocity (TPTV), peak untwisting velocity (PUV), time to peak untwisting velocity (TPUV) were separately measured. The results showed that the normal LV performs a wringing motion with a clockwise rotation at the base and a counterclock- wise rotation at the apex (as seen from the apex). The LVtw velocity showed a systolic counterclock- wise twist followed by a diastolic clockwise twist. Peak twist develops near the end of systole (96%±4.2% of systole). With aging, Ptw, AVCtw, MVOtw, HTU and PUV increased significantly (P<0.05) and UntwR decreased significantly (P<0.05). However, no significant differences in TPUV, PTV and TPTV were noted among the 3 groups (P0.05). It is concluded that LV twist can be meas- ured non-invasively by 2-dimensional ultrasound STI imaging. The age-related changes of LVtw should be fully taken into consideration in the assessment of LV function.