The Clinical Research Of Diagnosis Of Colorectal Carcinoma Using 64-vct And Multiple Post-processing Techniques

Background and purpose: Colorectal tumor is a kind of common malignanttumor in gastrointestinal tract, which be often diagnosised by traditional methods such as double-contrast barium enema (DCBE) and fibrous colonoscopy (FC) which are good at showing the lesions inside the colon but not good at demonstrating the lesions outside the colon, the blood supply of lesions, the depth of invasion, lymph nodes and remote organs metastasis. Spiral computed tomography (SCT) can offer pre-operation staging and grading of colorectal carcinoma and significantly improve the accuracy of clinic diagnosis of colorectal carcinoma. Before the using of volume CT, the pre-operation imaging information offered by CT is not too much since the limitation of machine and examination methods. With the spread using of multi-slice spiral CT (MSCT) ,especially 64-VCT,it comes into being that more and more image information can be offered to clinic diagnosis and therapy by large range volume scan and multiple-mode imaging post-processing techniques of MSCT. It is a hot focus recently that the colorectal carcinoma is diagnosed by using volume CT and its multiple post-processing techniques. The purpose of this study is to evaluate the clinical value of diagnosis of colorectal carcinoma using 64-VCT and multiple post-processing techniques.Materials and methods: Hypotonic Air and water enema, pre-contrast and multiple phases post-contrast scan were performed in 52 patients with colorectal carcinoma or doubting colorectal carcinoma before operation, then lesions or masses are demonstrated by using multiple post-processing techniques of 64-VCT and are made the detection, characterization and staging. Laxative was given to patients routinely before examination, then about 15 minutes before scanning, 10～15 mg 654-2 was injected intra- muscularly, then a Foley's tube was inserted into the rectum of patient to connect the auto enema machine and some moderate air was poured into the big intestine. Prone and supine pre-contrast scan was performed by 64-VCT.The scanning range is from the top of diaphragm to pubic symphysis, then the patient was required to pull out the air injected in the big intestine, then enema about 1500²000ml lukewarm water and pre and post-contrast scan was performed. All the scanning was finished when the patient hold breathe one time. The scanning raw data was transferred into ADW4.3 workstation and analysised. The post-processing methods include routine axial section, multiple planner reformation (MPR) , curved planner reformation (CPR) , virtual dissection (VD) , maximum intensity projection (MIP) ,computed tomography virtual endoscopy (CTVE) ,volume rendering (VR) ,surface shaded display (SSD) ,Raysum imaging. Then the detection, characterization and TNM staging was made. Statistical analysis was performed with SPSS 13.0 software, using Chi-square test in the counting data and Kappa test was used to compare two kinds of diagnosis methods, statistically significant level was considered as "alpha equals 0.05".Results:1. Hypotonic Air and water enema, pre-contrast and multiple phases post-contrast scan of 64-VCT were performed in 52 patients, good imaging of 49 patients were obtained and were reconstructed perfectly which demonstrated lesions clearly but 3 patients with severely narrow of big intestine.2. The location of lesions and the narrow degree of intestinal canal were better demonstrated in SSD and Raysum imaging, the intestinal canal structure and the surface of lesions in CTVE, intestinal canal was split axially and the whole colon was unfolded, the range of lesions and the lesions of others colon were displayed in VD, tumor feeding arteries in CTA and MIP, the enhancement of tumor, the circumintestinal invasion of tumor and lymph nodes and remote organs metastasis in axial section with MPR and CPR together, with using compositely of multiple post-processing techniques of 64-VCT,the lesions could be clearly and stereoscopically demonstrated.3. The accuracy of pre and post-contrast scan of 64-VCT and reconstruction of multiple post-processing techniques was 100.00% (52/52) in location. The accuracy of 64-VCT was 75.56%(34/45) in total TNM staging of colorectal carcinoma and 83.33% (5/6) in I stage, 81.25% (13/16) in II stage,69.57%(16/23) in III stage respectively. CT staging has better consistency with pathologic staging (the value of Kappa=0.645, p=0.000) .The accuracy of T staging of colorectal tumor was 88.89% (40/45) and respectively 83.33% (5/6) in T₂ stage, 89.29% (25/28) in T₃ stage,90.91% (10/11) in T₄ stage. The accuracy of N staging of colorectal tumor was 77.78% (35/45) and respectively 90.91%(20/22) in N₀ stage,63.16% (12/19) in N₁ stage,75.00% (3/4) in N₂ stage.4. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of serosa-infiltration of colorectal carcinoma by CT are 97.44%(38/39) ,83.33% (5/6) ,97.44% (38/39) ,83.33% (5/6) and 95.56% (43/45) .The value of Kappa =0.808, p=0.000,the result of CT has better consistency with pathologic results.5. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of lymph nodes metastasis of colorectal carcinoma by CT are 89.47% (17/19) ,84.62% (22/26) ,73.91% (17/23) ,90.91% (20/22) and 86.67%(39/45) .The value of Kappa=0.645, p=0.000, the result of CT has better consistency with pathologic results.Conclusions:1. With the using of 64-VCT and multiple post-processing techniques together, image resolution significantly is improved and imaging information become easier. After scanning just only one time, abundant and multiple imaging information is offered to ready to precoloproctectomy, release the oppression of patients, accurate diagnosis of detection, characterization and staging of colorectal carcinoma.2. It is a kind of reliable technique that perfect preparation of the big intestine before examination, both using of air and liquid contrast medias together can get the best image and finish the examination well.3. Every post-processing technique has its advantages and disadvantages, which should be flexibilitily used with others together. More colorectal carcinoma information can be obtained by MPR which is helpful to improve the accuracy of staging , tumor blood feeding by VR and MIP, CTVE,VD, SSD及Raysum imaging are similar to fibrous colonoscopy and barium enema.4. The accuracy of TNM staging of colorectal carcinoma was apparently improved by 64-V CT, which can be helpful to choose a better therapy for patients.