Objective To study the clinical value of colorectal carcinoma exa mination by comparison of different postprocessing techniques such as multiplana r reformation(MPR),CT virtual colonoscopy(CTVC), shaded surface display(SSD) a nd Raysum. Methods 64 patients with colorectal carcinoma s underwent volu me scanning using spiral CT. MPR, CTVC, SSD and Raysum images were obtained by u sing 4 different softwares in workstation. All cases were proved by surgical or CC bioptic histology. The results were compared and analyzed according to the circumferential extension, length and pathologic patterns of colorectal carcinoma with MPR, CTVC, SSD and Raysum. Results The correct ion rate of dete rmination the circumferential extension of colorectal carcinoma with MPR, CTVC, SSD and Raysum were 1000%, 828%, 797% and 797%, respectively There wa s signi ficant statistical difference between MPR and CTVC; The accuracy of judging the leng th of carcinoma were 891%, 766%, 953% and 1000%, respectively. There wa s stat istical difference between CTVC and SSD; The accuracy of showing carcinoma patho logi c patterns were 813%, 922%, 719% and 719%, respectively. There was stati stica l difference between CTVC and SSD, too. MPR could correctly determine the circum ferential extension of colorectal carcinoma. In determination the length of carc inoma, Raysum was more accurate than SSD. CTVC could be more helpful in showing carcinoma pathologic patterns. Conclusion There were advantag es and disadvant ages in colorectal carcinoma examination with MPR, CTVC, SSD and Raysum, and the combination could display colorectal carcinoma more completely and comprehensiv ely.

Objective To analyze the time-density curve of the small HCCs in the arterial phase and to find out its unique features.Methods All lesions were imaged with single-level serial SCT.The attenuations of the lesion,hepatic artery and hepatic parenchyma were measured.The time-density curve was built with these CT values and their corresponding times.Results The time-density curves of the lesion and liver parenchyma were divided into three kinds:the first kind had two intersects(73%).The first one was seen at the time when the curve of the lesion went up over the one of the parenchyma and the second was seen at the point the curve came down below the parenchyma's.There was no second intersecting point in the second type(19.2%) and the curve of the lesion was below that of the parenchyma in the third (7.7%). Conclusion The initial time of the enhancement of small SHCC is (21.6?6) s.The optimal time of the enhancement of SHCC is (36?8) s.

Background: CT scan of hepatic carcinoma after transarterial embolization with Lipiodol (LP-TAE) will be influenced. A comparative study was made between CT scan and hepatoarteriography in hepatic carcinomas fully filled with Lipiodol after TAE for the purpose of demonstrating the difference. Materials and Methods: 20 cases of hepatic carcinoma fully filled with Lipiodol after TAE 1 to 8 months, confirmed by CT scans. Hepatoarteriography were then done 1 to 14 days afterwards. The demonstration of the original and new foci were thus be compared respec- tively by these methods. Results: The original tumor lesions were all stable on CT scans and new tumor lesions were found in 5 cases. Three features were found in arteriographies of the original tumor lesions: (1) stable, no obvious tumor vessels and stain; (2) tumor vessels and stains confined within the LP accumulated areas; (3) largely increased lesions exceeding the LP accumulated areas; (3)largely increased lesions exceeding the LP accumulated areas. Also other three features were found in new tumor lesion: (1) multiple intrahepatic daughter nodules; (2)small arterioportal shunts; (3) new masses. Conclusion: (1) Although good results had been archieved, but the lesions were not stabe in many of them. Long interval follow-up and TAE were not suitable. (2) Stage-Ⅱ surgical resection should be taken cautiously. (3) New techniques of CT scan and superselective he- patic arteriography with high flow rate should be adopted to improve the accuracy rate of de- monstrating tumor lesion.

Objective　To optimize the oral contrast media in three-dimensional display of gastric lesions. Methods　41 cases were randomly divided into 3 groups according to different oral contrast media administered: No. 1 air contrast group (n=17), No. 2 fat emulsion group (n=7) and No. 3 positive contrast group (n=25). The 3D CT images were reconstructed using MPR, SSD, RaySum display and virtual endoscopic techniques, and compared with gastric endoscopy and/or conventional barium study.Results　The detectability of gastric lesions using fat emulsion and air contrast was 42.8%(3/7) and 80.0%(20/25), respectively, both were significantly lower than that using positive contrast (100%, 30/30) (χ2=19.22,P＜0.01;χ2=6.60, P＜0.05). The capability of showing the details of stomach lesions was significantly affected by the oral contrast media administered（χ2=17.04，P＜0.01）. Conclusion　It is very important to choose the appropriate oral contrast media for 3D display of gastric lesions in spiral CT, the positive contrast agent is the optimal choice.

Objective　To evaluate the value of gradient-echo chemical shift imaging in detection of lipid-containing abdominal lesions. Methods　35 patients with abdominal lesions were divided into 2 groups according to whether or not they contained lipid. Breath-hold in-phase(IP) and opposed-phase(OP) acquisitions were performed. The demonstration of these lesions on IP and OP was compared. The signal intensity of these lesions on both images was measured. The percentage of signal intensity variation on IP and OP was calculated and statistically analyzed with non-parametric method between the 2 groups. Results　For lesions containing lipid, the signal intensity dropped significantly from IP to OP, with median value of signal intensity variation attaining 37.1%. On the other hand, for lesions not containing lipid, the signal intensity did not change obviously between IP and OP, whose median value of signal intensity variation was 3.3%. The difference between the 2 groups was statistically significant (u=4.56，P<0.01). Conclusion　Gradient-echo chemical shift imaging is an easy and practical way, helpful to detection of lipid component within abdominal lesions.

Objective To define the CT imaging characteristic of menetrier disease. Methods Four patients with proved Menetrier disease were retrospectively studied by means of CT performed with the water as oral contrast, hypotonic agent and dynamic or spiral CT technique. Results All cases showed that the enlarged rugae were seen projecting into the gastric lumen, but the gastric wall was otherwise normal. CT detected all lesions and made a confirmed diagnosis before pathology biopsy. Conclusion Our primary result revealed that the CT appearance of Menetrier disease was quite characteristic, CT is a very valuable tool for the diagnosis of Menetrier disease.

Objective To evaluate the usefulness of three dimensional dynamic contrast enhanced magnetic resonance angiography(3D DCE MRA) in the diagnosis of vena caval abnormalities. Methods 3D DCE MRA was performed on fifty two patients with suspected vena caval anomaly, thrombosis, stenosis, occlusion, or compression. Image quality and the presence of venous abnormalities and collaterals were evaluated. Comparison with conventional venacavography( n =15) and surgical findings( n =18) was made. Results 3D DCE MRA images were of diagnostic quality without artifact for all 52 patients. 3D DCE MRA clearly showed vascular anatomy, anomaly and various disorders. The site, extent, cause of venous obstruction, and collateral pathways were well depicted. According to venography or surgery, the sensitivity and specificity of 3D DCE MRA in the diagnosis of abnormalities of vena cava were both 100%. In addition, it had advantages regarding demonstration of extravascular lesions and multiplanar capabilities. Conclusion 3D DCE MRA is simple to perform and accurate in detecting various vena caval abnormalities.

Objective To investigate the curative effect and influential factors of small hepatocellular carcinoma (SHCC) treated by interventional therapy. Methods 42 patients with SHCC were treated by interventional therapy. Some possible prognostic factors were analysed with COX proportional hazard regression model. Results (1)Hepatic arteriographic manifestations: 26 of 42 cases SHCC revealed rich tumor vessels, 37 had tumor stain including 34 with nodular stain. (2)The overall 1 , 3 , 5 year survival rates of SHCC using Kaplan Meier method were 88%(37/42),74%(31/42),51%(21/42), respectively. (3)Clinical staging and typing of the patients,and accumulation of Lipiodol within the tumor obviously influenced interventional effects of SHCC. Conclusion (1) The most important diagnostic angiographic sign of SHCC is tumor staining, besides tumor vessels. (2) Interventional therapy of SHCC has an ideal effect and should be an important nonoperable curative method.

Objective To investigate the safety and efficacy of placement of self expandable metallic stent within right atrium and inferior vena cava (ICV) in patients with malignant ICV obstruction involving right atrium. Methods There were 5 male patients with advanced hepatocellular carcinoma, aged from 42 to 65 years (mean 56 3 years). The malignancies invaded right atrium and ICV simultaneously, and caused obstruction of ICV. These patients presented symptoms and signs of obstruction of ICV such as hepatomegaly, ascites, edema of lower extremities. “Z” type stainless steel stents (7 5～10.0 cm in length and 2 5 cm in diameter) were selected for these patients. Part (1.0～3.0 cm in length ) of stent was placed in right atrium and the rest was in ICV. Results All of stents were placed successfully and obstructed ICV reopened. The symptoms of obstruction of ICV relieved or disappeared. There were no recurrence of symptoms of obstruction of ICV and any cardiac complication related to placement of stents in follow up period (67～188 days). Conclusion Placement of self expandable metallic stent within right atrium and ICV in treatment of patients with malignant ICV obstruction involving right atrium is one of the safe and effective methods.

Objective To investigate the MR features of uterine leiomyomas and evaluate its diagnostic value. Methods Twenty six patients with probable uterine leiomyomas underwent preoperative ultrasound, T 1 weighted spin echo and T 2 weighted fast spin echo MR examinations. Among them, 11 cases were performed with dynamic contrast enhancement. Comparative analysis between MRI findings and pathologic results was done. Results MRI diagnosis in all cases was consistent with the results given by surgery and pathology, except 2 being pathologically proven as endometrial polyp or inflammatory pseudoplasma. The diagnostic accuracy of MRI was 92%, while the accuracy of ultrasound was 85%. The difference between the number of lesions detected by two modalities had statistical significance (89% for MRI vs 69% for ultrasound, ? 2=17.86, P