Study Of 16-slice Spiral CT Portography With Bolus Tracking Trigger Scan Technology And Clinical Application

Part I Study of 16-slice spiral CT portography with bolus tracking trigger scan technologyPurpose1. To investigate main technique control of 16-MSCTP with bolus tracking trigger scan technology, and to explore the best trigger point trigger scan threshold CT value for 16-MSCTP with bolus tracking trigger scan technology.2. To evaluate the impact of the portal vein, hepatic parenchyma enhanced CT value, PV-L and the delay time by different thresholds value, and to evaluate the three-dimensional reconstruction image quality of MSCTP with MIP and VR. The difference ability level of display branch of portal between MIP and VR reconstruction were compared.Materials and methods1. 100 cases were healthy volunteers have been examined by 16-slices spiral CT scanner using bolus tracking trigger scan technology in the second affiliated hospital of Guangzhou Medical College , which were selected randomly. 60 cases were male and 40 cases were female, the oldest was 62 years and the youngest was 22 years old, the average age was 43±11 years old, the average weight was 61.5 Kg. Selection criteria for healthy people cases were without significant liver disease, such as hepatitis, liver cirrhosis and so on, ultrasound, CT, MR imaging examination, one and two pairs of semi-hepatitis ,liver function laboratory tests were normal; At the same time did not result in changes in liver blood system dynamics diseases of other systems, such as heart failure, massive ascites, and so on. 100 healthy volunteers were divided into five groups randomly by five different trigger scan CT threshold value with bolus tracking technology trigger scan, each group improved 20 cases. Five groups trigger scan CT threshold value were set: (1) trigger scan CT threshold value of group 1 was 5Hu, means the strengthening CT value of the trigger point achieved 5Hu that is to trigger MSCTP scan; trigger scan CT threshold value of group 2 was 10Hu, means the strengthening CT value of the trigger point achieved 10Hu that is to trigger MSCTP scan; trigger scan CT threshold value of group 3 was 15Hu, means the strengthening CT value of the trigger point achieved 15Hu that is to trigger MSCTP scan; trigger scan CT threshold value of group was 20Hu, means the strengthening CT value of the trigger point achieved 20Hu that is to trigger MSCTP scan; trigger scan CT threshold value of group 5 was 25Hu means the strengthening CT value of the trigger point achieved 25Hu that is to trigger MSCTP scan.2. Plain and portal venous-phase scan use fixed-point scan with 16-slice spiral CT by Germany's Siemens Sensation machine, which slice thickness is 7.0mm. First ,the whole liver were examined from diaphragm top at begin in plain scan. According to the results of plain scan, choose trigger point and set threshold values of groups in right lobe without vascular and bile duct, ROI area set 1.0cm2. Trigger scan CT threshold value of group 1 was set to 5Hu, trigger scan CT threshold value of group 2 was set to 10Hu, trigger scan CT threshold value of group 3 was set to 15Hu, trigger scan CT threshold value of group 4 was set to 20Hu, trigger scan CT threshold value of group 5 was set to 25Hu. After injection of contrast agent start with the layer of dynamic CT scanning to monitor the trigger point and describe changes in the value of time - the density curve at the same time. To reach or exceed the preset threshold, (delay 5s) a formal scanning were automatically trigger. Subjects were asked breath-hold during the same floor dynamic monitoring scan, and to breathe slowly shallow line during the portal venous phase scan. Contrast agent used syringes single-phase high pressure injection, which injection rate is 3.6 ml / s and non-ionic contrast agent ultravist is 1.5 ml/L (300mg/ml).3. CT value of abdominal aorta, portal vein, liver parenchymacwere measured in plain scan and portal venous-phase respectively, average enhancement CT value was calculation. Each liver obtain four region of interest(ROI)in every phase, each area is 1.0cm2,which are located left lobe, right lobe, quadrate lobe, caudal lobe, all measurement avoid impact of blood vessels and bile vessel, and took their average CT value as liver parenchyma. To ensure the accuracy of vascular measurements ,ROI was in the central district and the measurement diameter occupy all blood vessels 70% or more, besides,all measured should avoid effects of calcification and volume. The portal vein trunk measurements stand as portal vein, and chose mid-point of portal vein trunk to measure. Abdominal aorta measured in the celiac level.4. After the end of the scans,each subjects, portal venous phase volumetric data were sent to the Siemens Wizad 5.1 workstation, using 2.0 mm slice thickness, 1.0 mm spacing to reorganized the axial images. Followed, used maximum intensity projection (MIP) and volume rendering (VR) methods for three-dimensional reconstruction of portal vein. Portal vein three-dimensional reconstruction images quality were evaluated by the standard of Tarahashi portal standard: A (Excellent): able to clearly show the portal vein above the five branches (portal vein trunk as the first branch); B (good): able to clearly show the portal vein of the first-fourth branches; C (normal): the portal vein can be seen the first-third branches; D (poor), the portal vein did not show the third branches. Two attending physician in radiology department evaluated the images with blind score and the same quality evaluation standar.ResultThe enhancement CT value of abdominal aorta in five groups were:211.45±47.70 Hu,147.19±32.93Hu,110.16±29.57Hu,91.25±21.50Hu,82.05±17.94Hu; the enhancement CT value of the portal vein in five groups were:59.26±17.54Hu,110.75±20.92Hu,156.35±25.02Hu,128.31±30.03Hu,104.06±13.48Hu;the enhancement CT value of hepatic parenchyma in five groups were:13.93±2.35Hu,21.15±8.90Hu,33.49±4.79Hu,36.63±5.53Hu,44.56±9.56Hu ; the enhancement CT value of differences between the portal vein and liver (PV-L) in five groups were:37.39±10.46 Hu, 65.98±18.75 Hu, 96.21±15.38Hu, 75.14±14.57Hu, 52.39±15.46Hu, and the delay time were :31.39±3.46s, 35.79±4.17s,40.50±4.99s, 45.25±5.09s, 49.92±6.34s. The visualization rates of up-fifth order branch of portal vein were 30%, 65%, 95% ,80% ,40%. The Enhanced CT of portal vein and PV-L of Group 3 were the maximum value in groups, and image quality were the best,showed the trigger point threshold value for Group 3 (trigger scan CT threshold value is 15Hu) as the best threshold value for 16-MSCTP with bolus tracking trigger scan technology. The difference ability level of display branch of portal between MIP and VR reconstruction was not statistically significant.Conclusion1. Using amount of contrast agent 1.5ml/kg, injection rate of 3.6ml/s, choose trigger point and set threshold values of groups in right lobe without vascular and bile duct, the trigger scan CT threshold value set to 15Hu (means the strengthening CT value of the trigger point achieved 15Hu), is a good scan parameters for 16-MSCTP with bolus tracking trigger scan technology, and the higher quality three-dimensional image of the portal vein can can be obtained. 2. 16-MSCTP with bolus tracking trigger scan technology can monitor individual differences and improved visualization rates of fifth-sixth order branch of portal vein, and trigger scan CT threshold value in Groups 3 (trigger scan CT threshold value is 15Hu) is the best for 16-MSCTP with bolus tracking trigger scan technology. And the technology is easy to operate, just in the ordinary contrast agent injection speed and contrast concentration,can get a good image of the portal vein vascular imaging, means the technology have great clinical application value. Part II Clinical application of 16-slice spiral CT portography with bolus tracking trigger scan technologyPurposeUsing 16-MSCTP with bolus tracking trigger scan technology examined 53 patients with liver and pancreatic diseases by the technology parameters of Group 3 in part one, to explore clinical application value of 16-MSCTP with bolus tracking trigger scan technology.Materials and methods1. Using 16-MSCTP with bolus tracking trigger scan technology examined 53 subjects with liver or pancreas diseases, include 25 cases of liver cancer, 8 cases of liver cirrhosis, 9 cases of hepatic hemangioma, 6 cases of hepatic cyst, 5 cases of pancreatic cancer, and everage ages were 55±13 years old.2. Plain and portal venous-phase scan use fixed-point scan with 16-slice spiral CT by Germany's Siemens Sensation machine, which slice thickness is 7.0mm. First, the whole liver were examined from diaphragm top at begin in plain scan. According to the results of plain scan, choose trigger point and set threshold values of groups in right lobe without vascular and bile duct, ROI area set 1.0cm2. Trigger scan CT threshold value were all set to 15Hu. After injection of contrast agent start with the layer of dynamic CT scanning to monitor the trigger point and describe changes in the value of time - the density curve at the same time. To reach or exceed the preset threshold, (delay 5s) a formal scanning were automatically trigger. Subjects were asked breath-hold during the same floor dynamic monitoring scan, and to breathe slowly shallow line during the portal venous phase scan. Contrast agent used syringes single-phase high pressure injection, which injection rate is 3.6 ml / s and non-ionic contrast agent ultravist is 1.5 ml/L (300mgI/ml).3. After the end of the scans,each subjects, portal venous phase volumetric data were sent to the Siemens Wizad 5.1 workstation, using 2.0 mm slice thickness, 1.0 mm spacing to reorganized the axial images. Followed, used maximum intensity projection (MIP) and volume rendering (VR) methods for three-dimensional reconstruction of portal vein. Portal vein three-dimensional reconstruction images quality were evaluated by the standard of Tarahashi portal standard: A (Excellent): able to clearly show the portal vein above the five branches (portal vein trunk as the first branch); B (good): able to clearly show the portal vein of the first-fourth branches; C (normal): the portal vein can be seen the first-third branches; D (poor), the portal vein did not show the third branches. Two attending physician in radiology department evaluated the images with blind score and the same quality evaluation standar.Result:25 cases of liver cancer patients, MSCTP show the portal vein branch around foci were under pressure, displacement, thinning or disruption, 17 cases without tumor thrombus in portal vein, 15 cases MSCTP show portal vein up-fifth branches, 2 cases of patients with liver cirrhosis, MSCTP show visualization of 3rd to 4th order branch the portal vein , branches, branch rigid. 8 cases of patients with portal vein tumor thrombus formation, MSCTP showed involved intravenous low-density filling defect, proximal of tumor thrombus in portal vein were filled with contrast agent good, remote branches was filled with contrast agent poorly, which displayed visualization of 3rd to 4th order branch of portal vein; in the cases without tumor thrombus in portal vein can displayed visualization of 4th to 5th order branch;the portal vein trunk thrombosis or violate by tumor thrombus, portal vein branches show only 3rd to 4th order branch;1 case of inferior vena cava tumor thrombus formation, MSCTP showed low-density filling defect in the inferior vena cava; 1 case of hepatic arteriovenous fistula. 9 cases of hepatic hemangioma, 6 cases liver cyst, MSCTP showed portal vein take shape naturally, with the normal performance of similar, larger vascular lesions have changed over. 5 cases of pancreatic cancer patients,1 case MSCTP showed portal vein pressure and narrowed, portal vein trunk,the left and right branch were ectasia;1 case MSCTP showed violations of superior mesenteric vein.Conclusion:Using 16-MSCTP with bolus tracking trigger scan technology and examined liver and pancreatic diseases by the technology parameters of Group 3 in part one.The 16-MSCTP can accurately show three-dimensional visual anatomy of the portal vein, the relationship between the portal vein and the in liver and pancreas, the encroachment degree of the portal system, can provide more important information for clinical surgery and interventional therapy ;and can assess vascular damage in cirrhotic,show full view of portal vein thrombosis, cavernous transformation of portal vein and collateral circulation,contributed to the diagnosis and treatment of cirrhosis and portal hypertension. Therefore 16-MSCTP is a promising examination method which have features of non-invasive, intuitive and simple, that have great clinical value.