| Objective Our objective was to study the characteristics of the blood perfusion in normal and in mild acute pancreatitis(MAP) and severe acute pancreatitis(SAP), and to study the correlation of blood perfusion values with the Balthazar CT grading,CT severity index (CTSI) and acute physiology and chronic health evaluation II (APACHE II)of acute pancreatitis(AP) by discussing the MSCT perfusion values of AP and normal pancreas, including PS,BV, MTT and BF.Materials and MethodsClinical Materials Seventy-nine persons from Jan.2008 to Feb.2010 were enrolled in this study and all of them were undergone MSCT perfusion imaging. They were separated into two groups:AP (39 men,24 women; age range,21-76 years;mean age, 49.0 years±19.4) and the control group without pancreatic disorders(10 men,6 women, age arrange,29-64 years; mean age,43.6 years±16.8).The mean values of BF, BV, MTT and PS were measured on ADW 4.2 work station with perfusion 3 software packages.Statistical analysis between the two groups was performed.Imaging Protocol All patients were undergone CT examination within 48 hours. For this workup,16-MSCT (Light-speed, GE) was used with the following protocol:a first acquisition(120KVp,230mA,10-mm-thick,1.375-pitch,512x512 pixels) was obtained without IV injection of contrast materials. This series helped in locating the pancreas and setting the four dynamic acquisition slices at the correct level.Dynamic images(120kVp,120mA) were then obtained instead of the usual contrast-enhanced arterial phase. Four slices with a beam collimation of 5mm were set to cover as much of the pancreas as possible. Acquisition started simultaneously with IV injection of a 40ml bolus of iodinated contrast (350 mgl/ml of iodine) at a rate of 4 ml/sec into an antecubital vein by using a power injector after unenhanced abdominal CT. Perfusion CT scanning was initiated 8 seconds after injection of contrast materials.The sequence consisted of a 50-second series in cine mode during intravenous administration of iodinated contrast materials.Then 5 minutes later, the remaining 60ml contrast materials were injected at a rate of 3 ml/sec with two-phase contrast-enhanced scanning of the pancreas.Raw data were transmitted to workstation (ADW4.2) and analyzed by pancreatic perfusion software. Regions of interest (ROI) were set over pancreatic parenchyma and special care was taken not to include visible vessels, pancreatic duct and the edge of pancreas.Observation perfusion values Blood flow (BF),Blood volume (BV),Mean transit time (MTT)and Permeability surface (PS).Scoring and grading Every patient was scored according to the standard of Balthazar CT, CTSI and APACHEⅡ,and was grouped into mild acute pancreatitis (MAP)group and severe acute pancreatitis(SAP)group in accordance with the criteria of Balthazar CT and APACHEⅡrespectively.Statistical Analysis Using statistical software SPSS for windows 13.0 was to emphatically analyze the characteristics among the head,body and tail of normal pancreas, and the correlation between perfusion values and ages,and the difference between the men and women group by randomized block design multi-sample rank sum test,t-test,Spearman rank correlation and two independent samples rank sum test respectively, and also to emphatically discuss the difference among the control, MAP and SAP groups by Kruskal-Wallis rank sum test, and to discuss the correlation of perfusion values with the score of CTSI and APACHEⅡrespectively by Spearman rank correlation. The difference of p<0.05 was considered as statistically significant. Before parametric statistics the normal distribution and homogeneity of variance test had been made.Results1.The BF,BV,MTT, and PS values of control group were 155.38±27.64 (ml·100g-1·min-1),18.14±2.07(ml/100g),6.52±1.46(s) and3.03±1.77 (ml·100g-1min-1)respectively. There was no statistic difference among the head, body and tail of the normal pancreas,but there was a difference of BF between the two different age groups and a correlation between the BF and ages (p<0.01)except BV,MTT and PS (p>0.05). There was no statistic difference between the male and female groups.2.AP group were 71.54±18.68 (ml·100g-1·min-1),11.41±3.86(ml/100g),11.09±3.56 (s), and 29.26±8.81 (ml·100g-1·min-1) respectively. There was a significantly statistic difference of all perfusion values between the AP and control group. According to Balthazar CT grading standard,CT-MAP group were thirty-seven cases and the values of BF,BV,MTT, and PS were 81.14±16.74(ml·100g-1·min-1), 13.19±3.90(ml/100g),11.80±4.00(s) and27.44±8.14(ml·100g-1·min-1)respectively; CT-SAP group were twenty-six cases and the perfusion values were 57.89±11.51 (ml·100g-1·min-1),8.86±1.90(ml/100g),10.08±2.57(s) and 31.87±9.24 (ml·100g-1·min-1)respectively.According to APACHE II grading criteria,APACHEⅡ-MAP group were thirty-one cases and the perfusion values were 86.26±12.86(ml·100g-1·min-1), 13.97±3.71(ml/100g),11.73±4.30(s) and 28.31±8.69(ml·100g-1·min-1)respectively; APACHEⅡ-SAP group were thirty-two cases and the perfusion values were 57.29±10.58(ml·100g-1·mm-1),8.92±1.88(ml/100g),10.47±2.58(s) and 30.19±8.98 (ml·100g-1·min-1)respectively.According to Balthazar CT and APACHEⅡgrading criteria there was a significant difference of all perfusion values among MAP, SAP and control groups(p<0.01).By Spearman rank correlation, BF and BV values had negative correlation with CTSI and APACHEⅡscores (r=-0.817, r=-0.703;r=-0.865,r=-0.703.p<0.01). MTT and PS values did not have correlation with CTSI and APACHEⅡscoring(r=-0.185,r=0.094;r=-0.192,r=0.141.p>0.05).Conclusion1.There was no statistic difference among the head, body and tail of the normal pancreas, but there was a difference of BF between the two different age groups and a negative correlation between the BF and ages. There was no statistic difference between the male and female groups.This research was one of initiatives of this study.2.There was a significant difference of all MSCT perfusion values among MAP, SAP and control groups and there also was a correlation of MSCT perfusion values of BF and BV with the CTSI and clinical severity of acute pancreatitis.This imaging protocol helped in diagnosing MAP and assessing the severity and prognosis of acute pancreatitis.This research was another initiative of this study. |
PDF Full Text Request