Quality assurance of EBCT images is especially important in clinic. Factors influencing the quality of images are so variable and complex that comprehensive consideration should be paid to them. The analyses and researches for such factors as surrounding background, machine's inherent property and scanning parameters are made separately.

Objective To verify the usefulness of the corresponding compensation techniques for MRI artifacts after analyzing their generation mechanism. Methods Different compensation techniques were used to eliminate relative artifacts from the angle of improving background,calibrating software and hardware,editing parameters or instructing patients in scanning the patient or phantom with 1.0TMR and 1.5TMR. Results Artifacts were controlled to different extents and the quality of most MR images were improved. Conclusion Most artifacts can be eliminated completely by the use of corresponding compensation techniques while some others only be reduced a little or shifted.

Objective To verify whether it is useful to apply the corresponding preventive measures for the radio frequency(RF) field artifacts in MR images by the research of their influencing factors.Methods Preventive measures were taken according to the factors producing RF field artifacts in MR images.Results Various RF field artifacts in MR images were reduced,shifted or even eliminated completely.Conclusion Most RF field artifacts in MR images can be controlled by the application of the relative preventive measures.

Objective To evaluate the application effect of workload statistic software.Methods According to the actual workflow of the hospital and concrete management index sign,the workload of statistics procedure was designed using Dephi7.0.Results "Comprehensive Management System in Medical Imaging Department" run stable and accurate.What's more,its functions greatly facilitated workload statistics.Conclusion The system plays an important role in excellent workflow,exaltation of work efficiency,reasonable allotment of manpower and material resources,etc.

Objective To evaluate the clinical value of fMRI software.Methods Patients were scanned with the corresponding fMRI software to observe the change of imaging signals in tissue's functional zone.Results The signals in the relative functional zone of tissues varied with their functions.Consulation fMRI software has great value in such clinical applications as tissue physiology,biochemistry and metabolism functions.

Objective To master the various characteristics of EBCT and it's applications in clinic in depth. Methods Different scan modes were compared with each other. Results EBCT had the advantage of high speed in scanning and high resolving power of time without mechanical abrasion due to the using of electron beam. Conclusion EBCT is suitable for the examinations of cardiovascular system, and moving organs and uncooperative patients, and also for the application to CT fluoroscopy.

Objective To determine the effects of acute normovolemic hemodilution combined with deliberate hypotension induced by sodium nitroprusside on glomerular filtration rate. Methods Forty rabbits weighing 2.6-4.0kg were anesthetized with intramuscular ketamine(1mg?kg-1). The animals were tracheotomized and intubated.Anesthesia was maintained with 0.5% halothane inhalation and fentanyl infusion (2?g?kg-1?min-1 ) . Carotid artery was cannulated for blood pressure monitoring and blood gas analysis and external jugular vein was cannulated for CVP monitoring and blood sampling. The animals were randomly allocated to one of four groups of ten animals in each group: control group; deliberate hypotension group;hemodilution group and combined hemodilution-deliberate hypotension group. Deliberate hypotension was induced with 0.02% sodium nitroprusside and MAP was reduced to 35-40mm Hg. In hemodilution group and combined group blood was removed from artery until Hct was reduced to 20 % -25 % and normovolemia was maintained by simultaneous infusion of Ringer's lactate solution, 3 times the volume of blood removed. Glomerular filtration rate was assessed by inulin clearance rate. 1% inulin 3 ml was injected I. V. over 30 s and blood samples were taken from CVP line for determination of blood inulin concentration at 1,3,5, 10, 30, 60, and 100 min after injection of inulin. Results Urine output decreased significantly in hypotension group and increased in hemodilution group. There was no significantly difference in urine output between control and combined groups. Inulin clearance decreased significantly in hypotension group as compared with that in control group, but there was no significantly difference in inulin clearance between control and combined groups. Conclusions Deliberate hypotension can decrease renal blood flow and deliberate hypotension combined with hemodilution can maintain kidney microcirculation.

Objective To investigate the impact of LY294002 on the proliferation of cancer stem cell-enriched spheroid cells from human hepatocellular carcinoma via regulating phosphatidylinositol-3-kinaseprotein kinase B(PI3K-Akt)signaling pathway. Methods The cancer stem cell-enriched spheroid cells were genera-ted by culturing HepG2 cells in serum-free medium. LY294002(10,20,30 μmol/ L),an inhibitor of PI3K-Akt signaling pathway,was used in the experimental groups,without used in the control group. The impact of LY294002 on the spheroid cells proliferation was confirmed by cell counting kit(CCK-8 kit). The expression of Akt was tested by Western blotting. The expression of PI3K-Akt signaling pathway downstream genes such as decoy receptor 3(DcR3),mammalian target of rapamycin(mTOR),B-cell lymphoma(Bcl)-2 and Cyclin D1 were tested by real-time PCR. Results 30 μmol/ L LY294002 could inhibit the proliferation of spheroid cells, and significant difference in the absorbance(A value)was observed between the experimental group and control group[(0. 14 ± 0. 03)vs(0. 56 ± 0. 01),t = - 8. 915,P = 0. 000]. The expression level of phosphorylated Akt protein increased[(0. 57 ± 0. 08)vs(0. 16 ± 0. 42),t = 6. 027,P = 0. 026]. The mRNA of DcR3 [(0. 38 ± 0. 08)vs 1,t = 13. 060,P = 0. 006],mTOR[(0. 37 ± 0. 04)vs 1,t = 30. 363,P = 0. 001],Bcl-2 [(0. 26 ± 0. 04)vs 1,t = 33. 554,P = 0. 001]and Cyclin D1[(0. 10 ± 0. 02)vs 1,t = 63. 528,P = 0. 000] decreased. Conclusion LY294002 could inhibit the proliferation of cancer stem cell-enriched spheroid cells from human hepatocellular carcinoma via inhibiting PI3K-Akt signaling pathway.

Objective To explore the early diagnosis and treatment of acute superior mesenteric arterial embolism (ASMAE).Methods The clinical data of 25 patients with acute superior mesenteric arterial embolism were retrospectively analyed.Results All 25(100%) patients had severe abdominal pain with abdominal signs,21(84%) patients had history of valvular heart disease or atrial fibrillation,and 17(68%) patients had hematochezia.All the cases were misdiagnosed preoperatively,including 11 patients were misdiagnosed as abdominal pain of unknown causes,3 patients as acute pancreatitis,3 patients as acute gastroenteritis,2 patients as necrotizing enteritis.1 patient as acute appenditis,1 patient as acute myocardial infarction,and 1 patient as acute cholecystitis;but 3 patients were preoperatively suspected to have impairment of mesenteric blood flow.All of the 25 patients underwent necrotic bowel resection,6 patients died,and 7 patients abandoned treatment because of serious complications such as short bowel syndrome etc.Mortality rate was 51%(13/25).Conclusions Early diagnosis of patients with acute superior mesenteric arterial embolism is difficult;the main cause of misdiagnosis is lack of recognition of its clinical signs.Fully grasping the characteristics of patients with early stage disease and effective early intervention are the fundamental measures for reducing mortality.

OBJECTIVE:To provide references for perfecting the drug safety supervision mechanisms in China. METHODS:Based on the theory of“market failure”“contract failure”and“government failure”,representative drug safety supervision mecha-nisms were selected from USA for analysis and evaluation. RESULTS & CONCLUSIONS:USA has made some achievements in the implementation and application of drug safety supervision mechanisms. The representative drug safety supervision mechanisms included prescription drug applicant payment mechanism,drug safety information communication mechanism,punishment and in-centive mechanism, public-private partnership mechanism, passive monitoring and active monitoring combination mechanism. These mechanisms relieved“government failure”of FDA,and solved the problems of“market failure”and“contract failure”to cer-tain extent. In China,drug safety supervision mechanisms should be perfected from refining the legal guarantee,mobilizing exter-nal forces completely,absorbing and applying modern information technology,focusing on both prevention and disposal,paying at-tention to the coordination of different mechanism,striving for open procedure and transparent result.