CT Differentiation of Diffuse Malignant Peritoneal Mesothelioma, Tuberculous Peritonitis, and Peritoneal Carcinomatosis

Objective:To investigate the significance of computed tomography findings in diffuse malignant peritoneal mesothelioma(DMPeM),tuberculous peritonitis(TBP),and peritoneal carcinomatosis(PC)to differentiate the three diseases.Methods:The clinical manifestation and computed tomography scans of 147 patients with diffuse malignant peritoneal mesothelioma(n=60),tuberculous peritonitis(n=32),and peritoneal carcinomatosis(n=55)were retrospectively reviewed,while taking into account of ascites,pleural plaques,viscera infiltration;abnormalities in the peritoneum;involvement of the mesentery and omentum;as well as the presence and location of enlarged lymph nodes.Results:There was no significant difference among all three groups in terms of clinical manifestation,peritoneum,omentum,and mesentery involvement,ascites,as well as the presence and location of enlarged lymph nodes.The study found that 95%of DMPeM patients had been exposed to asbestos in the past.The patients showed significant differences in the following aspects:(1)irregular peritoneum thickening,caked omentum thickening,pleural plaques,visceral infiltration,and asbestos exposure were more common in peritoneal mesothelioma patients;(2)nodular peritoneum thickening and visceral metastasis were more common in patients with peritoneal carcinomatosis;(3)smooth peritoneal thickening,pleural effusion,and extraperitoneal tuberculosis were more common in patients with tuberculous peritonitis.Conclusion:A combination of computed tomography findings could improve our ability in differentiating the three diseases.

Mechanical and fatigue properties of SA508-Ⅳ steel used for nuclear reactor pressure vessels

The mechanical and fatigue properties of SA508-Ⅳ steel with martensite and granular bainite, respectively, were studied. The mechanical tests results showed that the ultimate tensile strength and impact toughness of the specimen with martensite were 830 MPa and 158 J, respectively, and those of the specimen with granular bainite were 811 MPa and 115 J, respectively. The former had higher tensile strength and impact toughness than the latter. The impact tests results showed that the former belonged to typical dimple fracture, while the latter belonged to brittle fracture. The fatigue tests results showed that the fatigue life of the specimen with martensite was 2717 cycles, and that of the specimen with granular bainite was 1545 cycles under the strain amplitude of ± 0.45%. The specimen with martensite had fewer crack initiation points, narrower fatigue striations separation, and larger volume fraction of high-angle grain boundaries than the latter. The fewer crack initiation points meant fewer fatigue cracks, the narrower fatigue striations separation meant slower crack propagation rate, and the larger volume fraction of high-angle grain boundaries could more effectively hinder fatigue crack propagation. Based on these facts, the fatigue life of the specimen with martensite was higher than that of the specimen with granular bainite.