Clinical Study On Pancreatic Hemodynamics And Assessment Of Resectability Of Pancreatic Cancer With SCT

Objectives:1. To study the homodynamics of normal pancreas and pathological pancreas by perfusion imaging technology with multi-slice spiral CT (MSCT).2. To study the assessment of resectability of pancreatic cancer and the invasion of pancreatic vessels by pancreatic cancer with spiral CT (SCT).Materials and methods1. Subjects: 30 normal control, 6 acute pancreatitis and 20 pancreatic cancer patients confirmed with pathologic histology were performed with 16-section multi-detector row CT scanning. 57 patients of pancreatic cancer confirmed by operation accepted single spiral CT or MSCT scanning in which 38 patients were examined with SSCT and 19 cases were examined with MSCT.2. Instruments and contrast agent: Somatom plus 4 SSCT scanner (Siemens, Germany), Light speed 16-section multi-detector row CT (GE, USA) with AW 4.2 workstation.Automatic CT injector with microcomputer and automatic injection pump (Medrad, USA)Non-ionic iodine contrast medium (300mgI/ml)3. Scanning methods:To perform routine axial scan on upper-abdomen in breath-holding and eupnea status. Dymamic enhancement scanning: perfusion scanning scope: 4 raw; target raw selection: head of pancreas, tail of pancreas and disease area, eupnea state, axial scan pattern, scanning time: 1 s, interval time: 1 s. Non-ionic contrast media Lohexol 50ml, injecting speed: 4.0 ml/s, 5.0 ml/s, 6.0 ml/s scanning began with 6s delay. Scan 30 times to generate 120 pieces of images and the total time was 60s. the scanning scope of vessel invasion: from uncinate process of pancreas to First Porta Hepatis, to perform artery phase, pancreas phase and portal vein phase dynamic scanning in breath-holding state.4. Image processing and data collection4.1 Image processing: To use the pancreas tumor arithmetic that self-prepared in perfusion 3 software (GE), aorta abdominalis was defined as input artery. The region of interest (ROI) of normal pancreas was head of pancreas and tail of pancreas. The ROI of pancreatitis and pancreatic cancer should avoid the necrotic area and ROI should avoid the vessels. In this way, the software would measure the CT value of scanning point of ROI and the time-density curves (TDC) of aorta abdominalis, head of pancreas, tail of pancreas, acute pancreatitis and pancreatic cancer were generated accordingly. From TDC, we could obtain the perfusion parameters such as blood flow (BF), blood volume (BV), mean transit time (MTT), and vascular permeability-surface (PS) et al. the measurements were repeated for 3 times to get the mean value.The CT angiography with SSCT got the original axial images with enhancement scanning. The MSCT measurements split and reconstructed the original data of artery phase and pancreas phase and transferred to AW4.2 workstation except the original axial images. The split intervals were 1.25 mm. The image were reconstructed with multiplanar reformation method.4.2 Data collection:4.2.1 To observe the TDC shape ot aorta abdominalis, normal head of pancreas, tail of pancreas, acute pancreatitis and pancreatic cancer.To store the time to peak (TTP) and peak value (PV) of aorta abdominalis, normal head of pancreas, tail of pancreas, acute pancreatitis and pancreatic cancer.To generate and store the perfusion parameters such as BF, BV, MTT and PS of normal head of pancreas, tail of pancreas, acute pancreatitis and pancreatic cancer.4.2.2 To observe pancreatic vessel invasions both in artery and veins. The arteries include celiac artery (CA) and its offshoot commom hepatic artery (CHA), slenic artery (SA), superior mensenteric artery (SMA). The veins include portal vein (PV), superior mensenteric vein (SMV) and splenic vein (SV). The invasion states are devided into 5 grades: 0, no invasion, fatty gap could be seen between tumor and vessel; 1, mild contraction between tumor and vessel (＜1/4 perimeter), the fatty gap disappeared; 2, convexity contraction between vessel and tumor (＜1/2 perimeter); 3, concave contraction between tumor and vessel or the vessel were encircled by tumor (＞1/2 perimeter); 4. the tumor encircled the vessel or the vessels were obstructed. The MSCT analysis still include the contraction length between tumor and vessel in the travel direction of vessel on MPR image: 1.＜10mm; 2, 10～20mm; 3,＞20mm, 4,＞20mm with far end vessel obstruction.5. Statistical analysis: The results of TTP, PV, BF, BV, MTT and PS were presented as mean±S.D. The difference between the two ROIs -- head of pancreas and tail of pancreas was tested with Student's t test. A P＜0.05 was taken as an appropriate level of significance. The differences among normal pancreas, acute pancreatitis and pancreatic cancer were tested with one-way ANOVA when Equal Variances Assumed and tested with Games-Howell test when equal variances not assumed.The tumor of resection was positive, not removable was negative. To calculate the sensitivity, specificity, positive prognostic value, negative prognostic value and accurate rate and to generate ROC curve to determine the best point of resection. Results (Chapt 1)All patients were ascertained by imaging or specific assay results. In total 20 pancreatic cancer patients, 11 cases were confirmed by pathology result, 4 cases were confirmed by puncture biopsy and the other 5 cases were confirmed by follow-up study.2.1 TDC configuration2.1.1 The TDC configuration of the head and tail of normal pancreas had no difference. The different injection velocity of contrast reagents could affect the TTP in which the shortest was the 6ml/s group (31.30±2.79 s), the longest was the 4ml/s group (35.90±3.60s). The TTP between 4 ml/s group and 5 ml/s group, 5 ml/s group and 6 ml/s group had no significant difference the TTP between 4 ml/s group and 6 ml/s group had significant difference. With the increasing of injection velocity, the TTP was shortened. The highest PV was the 6 ml/s group (107.37±7.63Hu), the lowest was the 4ml/s group (96.94±3.81Hu), the difference between the 4ml/s group and the 5 ml/s group, 4 ml/s group and 6 ml/s group were significant, the 5 ml/s group and 6 ml/s group had no significant difference. With the increasing of injection velocity, the PV showed an enhancing trend.2.1.2 Compared among normal pancreas, acute pancreatitis and pancreatic: cancer, the longest TTP was pancreatic cancer group (44.35±4.63s), the shortest was the normal pancreas group (33.80±3.73s). Compare the TTP between normal pancreas group and acute pancreatitis group, normal pancreas group and pancreatic cancer group, acute pancreatitis group and pancreatic cancer group, the difference were all significant. The highest of PV was the normal group (102.7097+6.85 Hu), the lowest was pancreatic cancer group (48.5500±10.80 Hu). Compare the PV value between normal pancreas group and acute pancreatitis group, the normal pancreas group and pancreatic cancer group, the acute pancreatitis group and pancreatic cancer group, all had significant differences.2.2 The perfusion result2.2.1 The BF, BV, MTT and PS had no significant difference between the head and tail of normal pancreas. Different injection velocity of contrast reagent had no effects on BF, BV, MTT and PS.2.2.2 The highest of BF was the normal pancreas group (188.15±18.30 ml·100mg-1·min-1), the lowest was pancreatic cancer group (43.23±12.79ml·100mg-1·min-1). The P value between normal pancreas group and acute pancreatitis group was less than 0.05 while the P value between normal pancreas group and pancreatic cancer group, acute pancreatitis group and pancreatic: cancer group were less than 0.01. The highest of BV was normal pancreas group (17.2013+2.07 ml·100mg-1), the lowest was pancreatic cancer group (3.8130±1.35 ml·100mg-1). There were significant differences between normal pancreas group and pancreatic cancer group, acute pancreatitis group and pancreatic cancer group while there was no significant difference between normal pancreas group and acute pancreatitis group. The longest of MTT was pancreatic cancer group (19.33±5.44s), the shortest was normal pancreas group (9.53±3.55s). There were significant difference between normal pancreas group and pancreatic cancer group, acute pancreatitis group and pancreatic cancer group while there was no significant difference between normal pancreas group and acute pancreatitis group. The highest of PS was pancreatic cancer group (33.0875±7.33 ml·100mg-1·min-1) while the lowest was normal pancreas group (9.1780±2.64 ml·100mg-1·min-1). There were significant difference between normal pancreas group and pancreatic cancer group, acute pancreatitis group and pancreatic cancer group while there was no significant difference between normal pancreas group and acute pancreatitis group. Results (chapt 2)To judge the resection possibility with SSCT and MSCT, grade was the proper grade that both the sensitivity and specificity were high. Use grade 2 as the standard of resection, the sensitivity, specificity, positive prognostic value, negative prognostic value and accurate rate of SSCT and MSCT were 93.1% and 93.8, 88.9% and 94.1%, 96.4% and 98.9%, 80.0% and 72.7%, 92.1% and 93.9%, respectively. MSCT was better than SSCT.Conclusions:1. The perfusion imaging with MSCT could measure the hemodynamic characteristics of normal pancreas and pancreatic disease. MSCT was a non-invasive method that suitable for multi-phase detection of both artery and vein, was the most ideal method in accessing the vessel invasion by pancreatic cancer.2. The perfusion parameters between the head and tail of normal pancreas had no significant differences. Different injection velocity of contrast reagents could affect the TTP and PV, the TTP delayed and PV lowered with low injection velocity, while the injection velocity had no effect on BF, BV, MTT and PS.3. The TTP was the shortest in normal pancreas group while was the longest in pancreatic cancer group. On the contrary, the PV showed a trend of vice versa. The BF between the normal pancreas group and acute pancreatitis group showed significant difference while the BV, MTT and PS were not. The BF, BV, MTT and PS between normal pancreas group and pancreatic cancer group, acute pancreatitis group and pancreatic cancer group showed significant difference—the normal pancreas showed high-perfusion while the pancreatic cancer showed low-perfusion, the acute pancreatitis group was in between.4. Use grade 2 of MSCT as the resection standard of pancreatic cancer, the sensitivity, specificity, positive prognostic value, negative prognostic value and accurate rate of MSCT were 93.8, 94.1%, 98.9%, 72.7% and 93.9%, respectively, were higher than that of SSCT. Combined the accumulated vessel length and width would improve the accurate of resection judgements.