Objective To evaluate the changes in the expression of spinal aquaporin-4 (AQP4) during remifentanil-induced hyperalgesia in a mouse model of incisional pain.Methods Seventy-two pathogen-free healthy adult male CD1 mice,weighing 25-30 g,were divided into 4 groups (n=18 each) using a random number table:control group (group C),incisional pain (group I),remifentanil group (group R) and remifentanil plus incisional pain group (group R+I).Normal saline was infused subcutaneously in group C.An incision was made in the left hind paw in group I.Remifentanil 80 μg/kg was subcutaneously infused for 30 min at a rate of 0.8 ml/h in group R.Remifentanil was infused subcutaneously before establishment of the model in group R+I.The thermal paw withdrawal latency (TWL) and mechanical paw withdrawal threshold (MWT) were measured at 1 day before establishment of the model (T0) and 6 h and 1,2 and 7 days after establishment of the model (T1-4).After measurement of the pain threshold at T3,12 animals were sacrificed randomly,and the lumbar segment of the spinal cord was removed for determination of the distribution and expression of AQP4 by Western blot.Results Compared with group C,the TWL was significantly shortened at T1-3,and the MWT was decreased at T2-4 in R and R + I groups,and the expression of AQP4 was significantly up-regulated at T3 in I,R and R+I groups (P＜0.05).Compared with group I,the TWL was significantly shortened at T2,3,and the MWT was decreased at T2.4 in group R,and the TWL was significantly shortened at T1-3,the MWT was decreased at T2.4,and the expression of AQP4 was up-regulated at T3 in group R+I (P＜0.05).Conclusion The mechanism by which remifentanil induces hyperalgesia is related to up-regulation of AQP4 expression in the spinal cord in a mouse model of incisional pain.

Objective To investigate the clinical value of three dimensional dynamic contrast enhanced MRA(3D DCE MRA)on esophageal and gastric varices compared with endoscopy.Methods From April 2003 to June 2008,153 patients with portal hypertension who underwent both 3D DCE MRA and endoscopy were reviewed retrospectively.All the patients were divided into bleeding group and non-bleeding group according to the clinical symptoms.The location and degree of the esophagogastric varices on 3D DCE MRA were assessed with postprocessing images,including subtraction,MIP and thin-slab maximum intensity projection(thin-MIP),and were compared with the results of endoscopy.The maximum,minimum and mean diameters of esophagogastric varices inside and outside of the wall were measured on the reformed images.The correlation between the findings of 3D DCE MRA and endoscopy were analyzed with Spearman rank correlation coefficient test The rates of esophagogastric varices outside of the wall in bleeding and non-bleeding group were compared by means of Chi-square test Results In bleeding group,severe esophageal varices were documented in 59 patients,moderate in 6 patients,mild in 5 patients;in non-bleeding group,severe esophageal varices were documented in 32 patients,moderate in 4 patients,mild in 5 patients.Severe,moderate,and mild gastric varices were documented in 28,34 and 16 in bleeding group,while they were 7,12 and 9 in non-bleeding group.Esophageal and gastric varices can be wholly presented on MIP images after subtraction,while the esophagogastric varices inside and outside of the wall can be differentiated on thin-MIP images.The location and degree of esophagogastric varices on 3D DCE MRA were correlated with the findings of the endoscopy.The range of r was from 0.544 to 0.878(P＜0.01).In 91 patients with severe esophageal varices,27 patients presented outside esophageal varices in bleeding group(n=59)and 24 patients presented outside esophageal varices in non-bleeding group(n=32).There was a significant difference in ratio of outside esophageal varices between bleeding group and nonbleeding group(X~2=7.199,P＜0.01).In 35 patients with severe gastric varices,22 patients showed adventitial gastric varices in bleeding group(n=28)and 4 patients showed adventitial gastric varices in non-bleeding group(n=7).The ratio of adventitial gastric varices in bleeding group was not significantly different from that of non-bleeding group(P=0.340).Conclusions 3D DCE MRA can display and differentiate the esophagogastric varices both inside and outside of the wall by three dimensional reconstruction.The results of 3D DCE MRA and endoscopy have good correlation.It is of importance in evaluating the esophageal varices outside of the wall,because they may indicate decreased risk of haemorrhage in patients with severe degree of esophageal varices.

Objective The purpose of our study was to investigate three dimensional dynamic contrast enhanced MR angiography(3D DCE M RA) in the detection of portosystemic collateral circulation in the falciform ligament in patients with portal hypertension. Methods From April 2003 to July 2008, 53 portal hypertension patients with varices in the falciform ligament were evaluated with 3D DCE MRA.Two radiologists independently assessed the number, diameter, location and drainages of the portosystemic collateral circulation in the falciform ligament according to the information on the 3D DCE MRA.Results The veins in the falciform ligament were classified into the superior and inferior groups, and both groups arise from the left trunk of the portal vein.In our study, the number of varices detected on 3D DCE MRA images varied from 1 to 3, and the diameters of these vessels varied from 0.4 to 2.6 cm.The inferior group consisted of paraumbilical/umbilical veins (47 cases), which flowed toward umbilicus and then drained upwards (n = 16) including deep superior epigastric veins (n = 7), superficial superior epigastric veins (n = 9), downwards (n = 40) including deep inferior epigastric veins (n = 7), superficial inferior epigastric veins (n = 33), or upwards and downwards at the same time (n = 9).The superior group of vessels in the falciform ligament were directly anastomosed with the internal thoracic vessels (n = 6).Conclusion In patients with portal hypertension, 3D DCE MRA can optimally demonstrate the portosystemic collateral circulation in the falciform ligament, which includes the superior and inferior drainage groups.

Objective To evaluate spleen autotransplantation with lower esophagus transection for the treatment of portal hypertension by three-dimensional dynamic contrast-enhanced magnetic resonance angiography (3D-DCE MRA). Methods Twenty-eight patients were randomly divided into study group undergoing splenic autotransplantation and cardia-esophageal devascularization plus lower esophagus transection and control group without splenic transplantation. The cross section area, blood velocity and blood flow of main portal vein (MPV) were measured by 3D-DCE MRA, and the blood flow, collateral circulation of transplanted spleen were assessed. Results The cross section areas (cm ) of MPV of the two groups decreased postoperatively ( study group 1. 80 ? 0. 69 vs. 1. 20 ? 0. 73 , t = 13.96, P = 0. 00; control group 1. 78 ? 0. 43 vs. 1. 29 ? 0. 57, t = 11. 38, P = 0. 00). The mean blood velocity ( cm/s) of MPV decreased postoperatively (study group 9. 85 ? 0. 09 vs. 7. 06 ? 1. 98, t = 18. 98 , P = 0. 00; control group 10. 01 ?0. 43 vs. 8. 19 ?2. 44, t =22. 32, P =0. 00) in the two groups, and the mean blood velocity ' of MPV in study group was lower postoperatively than that in control group ( t = - 8. 02, P = 0. 00 ) . The mean blood flow (ml/s) of MPV decreased postoperatively (study group 15. 05 ? 2. 43 vs. 10. 52 ? 2. 55, 1 = 16.93, P=0. 00; control group 14. 81 ?2. 29 vs. 11.58 ?2. 96, t = 15. 90, P=0. 00) , and the mean blood flow of MPV in study group was lower postoperatively than that in control group (t = - 2. 73, P = 0. 02). Extensive collateral circulation developed around the transplanted spleen. Conclusions 3D-DCE MRA clearly shows the autotransplantated spleen and portal hemodynamics. It is an important non-invasive way to evaluate the result of the procedures.

OBJECTIVETo investigate the influence of MRI on the T, N staging system, 5(th) edition, UICC and the 92 staging system, China by comparing CT and MRI of the nasopharyngeal carcinoma (NPC).

METHODSFrom 1993 to Dec. 2000, fifty-six NPC patients proved by pathology underwent CT and MRI examination with Philip T5-II ultra-magnetic system (0.5T) and Elscient CT twin flash. Routine axial scans by CT and SE sequence with axial, sagittal and coronal scans by MRI from oral pharynx (lower border of second cervical vertebra) to supracellar cistern were done with enhancement (50/56).

RESULTSThe tumor beyond the nasopharyngeal cavity was accurately defined because the pharyngobasilar fascia could be seen by MRI which appeared to be more sensitive than CT in revealing the invaded soft tissues surrounding the nasopharyngeal cavity, such as longus colli (14 by CT and 26 by MRI), tensor veli palatini and levator veli palatini (17 by CT and 42 by MRI), the skull base erosion (15 by CT and 23 by MRI) and enlargement of retropharyngeal lymph nodes (13 by CT and 24 by MRI). As a result, 28.6% (16/56) of NPC staging system, UICC and 33.9% (19/56) of the 92 staging system of China should undergo changes.

CONCLUSIONMRI is able to reveal the invasion extent into the structures around the tumor mass more accurately than CT, with the pharyngobasilar fascia readily seen and the infiltration and/or destruction of the skull base more easily visualized by MRI than by CT. The impact of MRI upon the 92 staging system of China lies in the differentiation of direct infiltration by the tumor from the enlargement of the retropharyngeal lymph node and the early detection of skull base erosion. The Influence of MRI on the staging system of NPC is more pronounced than that of CT.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Female ; Humans ; Magnetic Resonance Imaging ; methods ; Male ; Middle Aged ; Nasopharyngeal Neoplasms ; diagnosis ; Neoplasm Staging ; Tomography, X-Ray Computed ; methods