Study Of 64-detector Spiral CT Perfusion In Gastric Carcinoma

BackgroundGastric carcinoma (GC) is one of the most common malignant tumor of alimentary tract in china. The case fatality rate of GC is 23% of all malignant tumors, and it has many features, such as high attack rate, high death rate, poor prognosis. According to the report of literatures, the five years survival rate of early gastric carcinoma is high, but now most of the patients with gastric carcinoma who go to hospital presents with advanced gastric carcinoma, the five years survival rate of advanced gastric carcinoma is only 23.4%, effective treatment plan could extend patient's life span, and it depends on the overall assessment about gastric carcinoma before the operation, such as the range, the size, the extent, and the metastasis, pathology types and biological behaviour of gastric carcinoma. The routine examination of CT has the major superiority on judgeing the range, the size, the extent, and the metastasis of the pathological changes, but it is only restricted at the morphology. CT perfusion imaging is a kind of functional imaging, and could have a further fathom about the blood supply and the vasopermeability of the tumor, thus it conduces to the diagnosis and differential diagnosis of GC, TNM staging of GC, to evaluate the therapeutic effect, and so on.Aim①Through the study of 64-detector spiral CT Perfusion in Gastric Carcinoma, to approach the variability of gastric carcinoma and eu-stomach on perfusion plots, perfusion images, and perfusion parameters, to analyze gastric carcinoma's characteristic of perfusion plots, perfusion images, and perfusion parameters.②Through the study of 64-detector spiral CT Perfusion in Gastric Carcinoma, to approach the relationship between CT perfusion parameters and some factors affecting prognosis of gastric carcinoma, to identify it's value of diagnosing GC and clinical application.③To approach the relationship between metastatic lymphonode and primary focus of GC about perfusion plots, perfusion images, and perfusion parameters.④To approach the relationship between the 64-detector spiral CT perfusion parameters of GC and it's CT signs.⑤To approach the relationship between GC and interstitialoma on perfusion parameters, to identify the value of 64-detector spiral CT perfusion to discriminate GC and interstitialoma.Materials and methods1. Clinical data71 cases GC and 23 cases interstitialoma of stomach from March 2008 to November 2009 which were confirmed by pathology were collected.71 cases GC including 50 males and 21 females, with a median age of 58 years.23 cases interstitialoma including 6 males and 17 females, with a median age of 53 years. All patients didn't accept any therapy, and were performed 64-detector spiral CT perfusion(CTP) and stage-3 enhanced CT scan in one week before operation.10 cases with normal stomach underwent 64-detector spiral CT perfusion(CTP)were also collected as control group, including 7 males and 3 females, with a median age of 57 years.2. Scanning methodPatients on fasting, were asked to drink water 800-1000ml and were injected 654-2 10mg 15-20 minutes ago before scanning, used the GE 64-detector spiral CT for scanning. Concrete method as follow:Firstly, the patients were performed the routine plain scan, thickness and spacing 5mm, the pitch 0.984:1, scanner speed 0.8sec. Selected 8 decks of the focus on the basis of plain scan. Scanner mode of CT perfusion:axial full 1.0sec, thickness:5.0mm/8i, spacing:0,120kV/80mA, exposure time:50s. The patients were injected 50ml non-ionic contrast agent (Iohexol 300mg I /ml) at the speed of 4.0ml/s in the ulnar vein. The patients conventionally took abdominal belt and held breath for 50s during scanning, the aged people that could not hold breath for a long time were asked to take small breath. After the perfusion scanning, The patients were injected 100ml non-ionic contrast agent (Iohexol 300mg I/ml) at the speed of 3.0ml/s to complete the stage-3 enhanced CT scan of the epigastrium. This scan included three phases:Artery Phase (delay about 30s), Portal vein Phase (delay about 65s), and Delayed Phase (delay about 120s).3. Data processing and analysis3.1 The data processing and analysis of 3-stage enhanced CTThe volumetric data were transferred to computer workstation (ADW 4.3) to reformat the images as multiplanar reconstructions (MPR) and curvedplanar reformation (CPR). To measure the thickness, maximum diameter, and maximum enhancement numerus of the focus. 3.2 The data processing and analysis of CTP imageThe voulumetric data were transferred to computer workstation (ADW 4.3). The data was calculated, mapped and analysed using GE'S Pancreas tumor perfusion of CT perfusion-3.0 perfusion package to generate specific types of quantitative function images and perfusion parameters. The abdominal aorta in the series as supplying vessels were marked, size placed by 2-6 pixels in order to avoid partial volume effects. In order to wipe off the effects of the bone, fat tissue and air, the leak points were defined as 0-200Hu. Then regions of interest (ROI) was selected(>50pixels) that was far away from the edge of tumor and out of the way of great vessels and necrosis, then read the following perfusion parameters:blood flow (BF), blood volume (BV), mean transit time (MTT), permeability of surface (PS). The parametric figure and time density curve (TDC) of ROI was obtained. All measurements were done three times during the study period, and the average value was obtained.4. Statistical MethodsAll data were handled by SPSS 17.0 statistical package. Measurement data demonstrated in x±s, and the reference range 95% confidence interal used. Comparsion between two groups was done using independent sample t-test. Many groups were compared using one-way ANOVA. Multiple comparisons between mean was done with LSD if variance was regular and using Games-Howell method if variance was irregular. The correlation of parameters were analyzed by Pearson's method (enumeration), P<0.05 represented stastistical difference, P<0.01 represented a very significant stastistical diffence.Results1.64-detector spiral CT perfusion could offer the GC's information of blood and manifest its physiological function.2. The BF, BV, MTT, PS of the group of normal stomach is respectivly 40.53± 25.55ml/(100g.min),5.62±3.26ml/100g,14.37±8.74S,7.99±2.30ml/ (100g.min). The BF, BV, MTT, PS of the group of GC is respectivly 108.85±56.17ml/(100g.min),1.0.19±3.99ml/100g,8.23±3.57S,27.71±11.15 ml/ (100g.min). Comparsion between the two groups was done by using independent sample t-test. The results:t is respectively 6.523,2.027,-4.062,13.060. p is respectivly 0.000,0.046,0.000,0.000. The BF, BV, PS of the group of GC is greater than that of the group of normal stomach's, but the MTT of the group of GC is smaller than that of the group of stomach's. The differences all have statistical significance.3. The differences of PS of the three groups have statistical significance.4. The PS of GC has the relationship with the TNM staging and the metastasis of the lymphonode (P<0.05), doesn't have the reationship with ectoptygma infiltration and the metastasis of distant place. The BF, BV, MTT of GC do not have the reationship with the TNM staging, ectoptygma infiltration and the metastasis of the lymphonode and distant place(P>0.05).5. Compared the perfusion parameter values between the metastatic lymphonode and primarily focus of GC, the BF, BV have positive correlation (P<0.05), and BF has obviously dependability (P<0.01), but MTT, PS do not have dependablity.6. The BF, BV have positive correlation with the maximum enhancement value. The PS has positive correlation with the maximum diameter and the maximum enhancement value, and has obviously dependablity with the maximum enhancement value.7. The BF, BV, PS of GC are larger than that of interstitialoma of stomach's, the differences have statistical significance (P<0.05). The MTT of two groups is near, the differences have statistical significance. Conclusions1.64-detector spiral CT Perfusion in GC could reflect intuitively the changes of the perfusion parameters, and could objectively and quantizatly reflect hemodynamic changes.64-detector spiral CT Perfusion in Gastric Carcinoma combine with axial images and many postprocessing technique, could offer even more valuable informations for fixing,qualitation, and staging of GC. Therefore, CT Perfusion Imaging is an original and non-Invasive functional imaging method to evaluate bloodstream perfusion of tissue and organ.2. The PS is the most significant parameter index of all perfusion parameters, have relationship with differentiated degree, TNM staging, the metastasis of the lymphonode, the maximum diameter and the maximum enhancement value of GC, have higher accuracy rate of judging differentiated degree, TNM staging of GC, and is of great value in clinical application.3.64-detector spiral CT Perfusion has unvarying value on identifying GC and interstitialoma of stomach.