AIM:To distinguish acinar cell carcinoma(ACC)from pancreatic adenocarcinoma(AC)by comparing their computed tomography findings.METHODS:Patients with ACC and AC were identified on the basis of results obtained using su...AIM:To distinguish acinar cell carcinoma(ACC)from pancreatic adenocarcinoma(AC)by comparing their computed tomography findings.METHODS:Patients with ACC and AC were identified on the basis of results obtained using surgically resected pancreatectomy specimens.The preoperative computer tomographic images of 6 acinar cell carcinoma patients and 67 pancreatic adenocarcinoma patients in 4 phases(non-contrast,arterial,portal venous,and delayed phase)were compared.The scan delay times were 40,70,and 120 s for each contrast-enhanced phase.The visual pattern,tomographic attenuation value,and time attenuation curve were assessed and compared between AC and ACC cases using the 2test,Wilcoxon signed-rank test,and Mann Whitney U test.RESULTS:The adenocarcinomas tended to be hypodense in all 4 phases.The acinar cell carcinomas also tended to be hypodense in the 3 contrast-enhancedphases,although their computed tomographic attenuation values were higher.Further,5 of the 6 acinar cell carcinomas(83%)were isodense in the non-contrast phase.The time attenuation curve of the adenocarcinomas showed a gradual increase through the 4 phases,and all adenocarcinomas showed peak enhancement during the delayed phase.The time attenuation curve of the acinar cell carcinomas showed peak enhancement during the portal venous phase in 4 cases and during the arterial phase in 2 cases.None of the 6 acinar cell carcinomas showed peak enhancement during the delayed phase.CONCLUSION:The tumor density in the non-contrast phase and time attenuation curve pattern clearly differ between acinar cell carcinomas and adenocarcinomas,and multidetector-row computed tomography can thus distinguish these tumors.展开更多
Based on the similarity criterion, volcanic rock samples were taken from outcrops to make experimental models. Water flooding experiments of five-spot well pattern, nine-spot well pattern, five-spot to nine-spot well ...Based on the similarity criterion, volcanic rock samples were taken from outcrops to make experimental models. Water flooding experiments of five-spot well pattern, nine-spot well pattern, five-spot to nine-spot well pattern, the relationship between relative well and fracture positions, and injection rate in dissolution vug-cave reservoirs with/without fractures were carried out to analyze variation regularities of development indexes, find out development characteristics of water flooding with different well patterns and sort out the optimal water flooding development mode. For dissolution vug-cave reservoirs without fractures, five-spot well pattern waterflooding has very small sweeping area, serious water channeling and low oil recovery. When the well pattern was adjusted from five-spot to nine-spot well pattern, oil recovery could be largely improved, but the corner well far from the injector is little affected. In dissolution vug-cave reservoirs with fractures, when the injector and producer are not connected by fractures, the fractures could effectively connect the poorly linked vugs to improve the development effect of water flooding. Whether there are fractures or not in dissolution vug-cave reservoirs, the development effect of nine-spot well-pattern is much better than that of five-spot well pattern and five-spot to nine-spot well pattern, this is more evident when there are fractures, and the edge well has better development indexes than corner well. At the high-water cut stage of water flooding with nine-spot well pattern, the oil recovery can be further improved with staggered line-drive pattern by converting the corner well into injection well. It is helpful to increase the oil production of corner well of nine-spot well pattern by increasing the injection rate, and improve ultimate oil recovery, but the water-free production period would be greatly shortened and water-free recovery would decrease.展开更多
文摘AIM:To distinguish acinar cell carcinoma(ACC)from pancreatic adenocarcinoma(AC)by comparing their computed tomography findings.METHODS:Patients with ACC and AC were identified on the basis of results obtained using surgically resected pancreatectomy specimens.The preoperative computer tomographic images of 6 acinar cell carcinoma patients and 67 pancreatic adenocarcinoma patients in 4 phases(non-contrast,arterial,portal venous,and delayed phase)were compared.The scan delay times were 40,70,and 120 s for each contrast-enhanced phase.The visual pattern,tomographic attenuation value,and time attenuation curve were assessed and compared between AC and ACC cases using the 2test,Wilcoxon signed-rank test,and Mann Whitney U test.RESULTS:The adenocarcinomas tended to be hypodense in all 4 phases.The acinar cell carcinomas also tended to be hypodense in the 3 contrast-enhancedphases,although their computed tomographic attenuation values were higher.Further,5 of the 6 acinar cell carcinomas(83%)were isodense in the non-contrast phase.The time attenuation curve of the adenocarcinomas showed a gradual increase through the 4 phases,and all adenocarcinomas showed peak enhancement during the delayed phase.The time attenuation curve of the acinar cell carcinomas showed peak enhancement during the portal venous phase in 4 cases and during the arterial phase in 2 cases.None of the 6 acinar cell carcinomas showed peak enhancement during the delayed phase.CONCLUSION:The tumor density in the non-contrast phase and time attenuation curve pattern clearly differ between acinar cell carcinomas and adenocarcinomas,and multidetector-row computed tomography can thus distinguish these tumors.
基金Supported by the China National Science and Technology Major Project(2016ZX05014-003-004)
文摘Based on the similarity criterion, volcanic rock samples were taken from outcrops to make experimental models. Water flooding experiments of five-spot well pattern, nine-spot well pattern, five-spot to nine-spot well pattern, the relationship between relative well and fracture positions, and injection rate in dissolution vug-cave reservoirs with/without fractures were carried out to analyze variation regularities of development indexes, find out development characteristics of water flooding with different well patterns and sort out the optimal water flooding development mode. For dissolution vug-cave reservoirs without fractures, five-spot well pattern waterflooding has very small sweeping area, serious water channeling and low oil recovery. When the well pattern was adjusted from five-spot to nine-spot well pattern, oil recovery could be largely improved, but the corner well far from the injector is little affected. In dissolution vug-cave reservoirs with fractures, when the injector and producer are not connected by fractures, the fractures could effectively connect the poorly linked vugs to improve the development effect of water flooding. Whether there are fractures or not in dissolution vug-cave reservoirs, the development effect of nine-spot well-pattern is much better than that of five-spot well pattern and five-spot to nine-spot well pattern, this is more evident when there are fractures, and the edge well has better development indexes than corner well. At the high-water cut stage of water flooding with nine-spot well pattern, the oil recovery can be further improved with staggered line-drive pattern by converting the corner well into injection well. It is helpful to increase the oil production of corner well of nine-spot well pattern by increasing the injection rate, and improve ultimate oil recovery, but the water-free production period would be greatly shortened and water-free recovery would decrease.
