Preliminary Study On CT Perfusion Imaging Of Colorectal Adenocarcinoma And Its Lymph Node

Part one Imaging Features of CT Perfusion in colorectal adenocarcinoma and the clinical application valuePurpose: To study the computed tomography perfusion imaging features of colorectal adenocarcinoma and the correlation between the perfusion parameters of CT perfusion imaging with clinicopathological characteristics(the degree of differentiation, T stage, N stage, M stage, group, ENTD).Materials and Methods: 43 patients with histologically proven colorectal carcinomas by colonoscopy, underwent CT perfusion imaging, operation was performed after CT examination within 2 weeks, all patients had general assess to the tumor specimens,as well as complete reports were involved in this study. There are 20 maale cases and 23 female cases.Age ranges from 27-82 years old,with an average age of 63±19. Nine cases of tumors were located in cecal-ascending colon, 1 cases of transverse colon, 2 cases of descending colon, 9 cases of sigmoid colon, 22 cases of rectum. Fast for six hours before scanning.30-90 min before CT scan fill in the patient’s digedtive tract with 1500 m L of water-soluble contrast material with a concentration of 2%–4% meglumine. To prevent peristaltic movement, 10 mg of the spasmolytic agent racanisodamine hydrochloride Injection was injected intramuscular to all patients immediately prior to data acquisition. An abdominal band restraint was placed to minimize abdominal wall motion. Perform respiratory training in patients with fixed supporter before scanning.After the CT scan images based on the tumor location, select the target plane, the cubital vein with 4.0ml/s rate of injection 300 mg I/ml of iohexol 50 ml, after injection of contrast agent injected with saline at the same rate 20 ml. All patients were examined by using a sixty four–detector row CT scanner(GE Light Speed VCT). First, An abdominal-pelvic study was performed initially without intravenous contrast. The tumor was localized on the nonenhanced CT scan, and eight adjacent 5-mm sections were selected at the mid-level of the tumor for cine imaging. A dynamic study of this area was performed at a static table position during rapid intravenous bolus injection(4 ml/second) of 50 ml iohexol omnipaque containing 300 mg iodine per milliliter. The following parameters were four contiguous sections, each collimated to 5 mm(providing z-axis tumor coverage of 4cm), were obtained at 1-second intervals by using a cinemode acquisition(120 k V, 40 m A,1-second rotation speed). This acquisition commenced 8 seconds following the start of intravenous injection to allow acquisition of baseline nonenhanced images and continued for a total duration of 40 seconds. All scan data were transferred to a stand-alone workstation(GE Advantage Workstation 4.3). Viewing and analysis were performed initially by one radiologist with 3 years of experience in perfusion CT by using perfusion software that was based on distributed parameter analysis(Body protocol, Perfusion 3.0; GE Healthcare Technologies).The first of the eight 5-mm contiguous sections acquired was analyzed by using the software package as follows. A processing threshold of-200–120 HU was chosen to optimize soft-tissue visualization. An arterial input was defined by using the mouse to place a circular ROI, 10mm2 in area, in the best-visualized artery(aorta, iliac artery, or femoral artery) on the selected image. The region of interest was drawn freehand(using an electronic cursor and mouse) around the peripheral boundary of the visible tumor. Care was taken to exclude pericolonic fat and intraluminal gas, which was facilitated by viewing a cine loop of acquisition to gauge the degree of patient movement and the tumor margins. The arterial time enhancement curve was derived automatically by using the software, and resulting parametric maps were produced, with each pixel representing a parameter value. The parameters of tumor generated by the software were blood flow(TBF), blood volume(TBV), mean transit time(TMTT), and pemeability surface(TPS). All patients subsequently underwent surgery. Clinicopathological stage was estimated by the AJCC/UICC Staging System. Compare the variation in CT perfusion parameters of colorectal primary tumor among different clinicopathological characteristics(the degree of differentiation, T stage, N stage, M stage, UICC stage, ENTD), Analysis the correlation between CT perfusion parameters in terms of clinicopathological characteristics and the clinical application value. 64-detector helical CT perfusion imaging was performed in 43 colorectal adenocarcinoma patients. All cases were adenocarcinoma confirmed by pathology and underwent surgical resection followed by perfusion CT.Results: All tumors were histologically proven to be adenocarcinoma after surgery.,including 4 mucinous adenocarcinoma, 4 poorly differentiated, 32 moderately differentiated,3 well-differentiated cases. Among the 43 cases, there were 0,7,31 and 5 T1 tumors, T2 tumors, T3 tumors, and 3 T4 tumors, respectively. There were 25,12 and 6 N0,N1,N2 cases, respectively. There were 36 M0, 7 M1 cases, 6 cases with ENTD and 37 cases without ENTD.The mean values ± standard deviations for TBF, TBV, TMTT and TPS were, respectively, 91.570±47.038ml/100ml/min,5.408±2.556ml/100 g,5.917±3.400 s and 15.947 ±6.675ml/100g/min. There was no significant difference in different clinicopathological characteristics of tumor perfusion parameters(P > 0.05). The TBF value of low differentiation adenocarcinoma is less than the moderately differentiated adenocarcinoma and high differentiated adenocarcinoma, the difference was statistically significant(P < 0.05).A statistically significant difference in TPS values between T3 and T4 tumors was observed(p < 0.05). TBF, TBV values overall decreased with increasing T stage(TBF decreased from 106.882ml/100 ml/min with T2 to 61.611ml/100 ml/min with T4 tumors,TBV decreased from 5.712ml/100 g with T2 to 4.188ml/100 g with T4 tumors). Tumor MTT increased with increasing T stage(from 5.184 s with T2 to 7.918 s with T4 tumors). TBF,TBV values overall decreased with increasing N stage(TBF decreased from 103.223ml/100 ml/min with N0 to 65.308ml/100 ml/min with N2 stage, TBV decreased from 5.870ml/100 g with T2 to 4.611ml/100 g with T4 tumors). Tumor MTT increased with increasing N stage(from 5.291 s with T2 to 7.153 s with T4 tumors). TBF values overall decreased with increasing UICC stage(TBF decreased from 106.882ml/100 ml/min with Ⅰstage to 76.002ml/100 ml/min with Ⅳ stage). Tumor MTT increased with increasing UICC stage(from 5.184 s withⅠstage to 6.763 s with Ⅳ stage).Conclusion: The CT perfusion imaging may allow evaluate the perfusion and permeability in colorectal adenocarcinoma, still need further study.Part two Preliminary research on value of CTperfusion in assessing the status of lymph nodes in patients with colorectal adenocarcinomaPurpose: To study the CT perfusion imaging features of regional lymph node, the correction of the CT perfusion parameters between primary colorectal adenocarcinoma and lymph nodes, to evaluate their clinical value in assessing, the status of lymph nodes.Materials and Methods: 16 cases of colorectal adenocarcinoma patients with regional lymph node metastases were underwent CT perfusion imaging. CT examination was same with the part one. All scan data were transferred to a stand-alone workstation(GE Advantage Workstation 4.3). Viewing and analysis were performed initially by one radiologist with 3 years of experience in perfusion CT by using perfusion software that was based on distributed parameter analysis(Body protocol, Perfusion 3.0; GE Healthcare Technologies).The first of the eight 5-mm contiguous sections acquired was analyzed by using the software package as follows. A processing threshold of-200–120 HU was chosen to optimize soft-tissue visualization. An arterial input was defined by using the mouse to place a circular ROI, 10mm2 in area, in the best-visualized artery(aorta, iliac artery, or femoral artery) on the selected image. The region of interest was drawn freehand(using an electronic cursor and mouse) around the peripheral boundary of the visible tumor and lymph nodes. Care was taken to exclude pericolonic fat and intraluminal gas, which was facilitated by viewing a cine loop of acquisition to gauge the degree of patient movement and the tumor margins. The arterial time enhancement curve was derived automatically by using the software, and resulting parametric maps were produced, with each pixel representing a parameter value. The parameters of tumor and lymph nodes generated by the software were TBF, TBV, TMTT, TPS and NBF, NBV, NMTT, NPS. Analysis the perfusion parameters of the maximum metastatic lymph node(NBF,NBV,NMTT,NPS) and the correction between metastatic lymph nodes and primary colorectal adenocarcinoma, to study the computed tomography perfusion imaging features of metastatic lymph node and evaluate their clinical application value in assessing the status of lymph nodes.Results: The mean values ± standard deviations for TBF, TBV, TMTT, TPS were, respectively, 80.986±43.101ml/100ml/min、5.017±1.784ml/100g、6.590±3.537 s and 16.758 ±5.696ml/100g/min. The mean values ± standard deviations for NBF,NBV,NMTT,NPS were, respectively, 56.605±38.112ml/100ml/min、4.150±2.664ml/100g、7.028±4.278 s and 14.844 ±12.200ml/100g/min. Correlation coefficien of CT perfusion parameters of colorectal primary tumor and the metastatic lymph nodes was r=0.294, 0.410, 0.534,0.095 and P=0.269、0.114、0.033、0.725), respectively. Paired Samples Test of the metastatic lymph nodes and the colorectal primary tumor,the t value of BF、BV、MTT and PS is 2.014, 1.374,-0.458, 0.591,and the P value is 0.062、0.190、0.654、0.563,respectively.Conclusion: The CT perfusion imaging may allow evaluate the blood perfusion in colorectal adenocarcinoma and regional lymph node, the correlation still need further study.