Objective To investigate the effects of different contrast injection schemes on the image quality of triple-rule-out com-puted tomography angiography(TRO-CTA).Methods A total of 691 patients with acute chest pain who underwent TRO-CTA exami-nation from multiple centers were prospectively selected and randomly divided into mixed group and unmixed group according to dif-ferent contrast injection methods.The image quality of aorta,pulmonary artery and coronary artery in the two groups was evaluated subjectively and objectively and the radiation dose was calculated.Results There were no significant differences in subjective image quality scores,aorta and coronary CT values,signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)between the two groups(P>0.05),while there were significant differences in pulmo-nary CT values,SNR,CNR and radiation dose between the two groups(P<0.05).Conclusion The utilization of a mixed contrast injection scheme in TRO-CTA can satisfy diagnostic require-ments while ensuring a low proportional dosage and reduced radiation dose,which has clinical application value.

Objective To investigate the effects of different contrast injection schemes on the image quality of triple-rule-out com-puted tomography angiography(TRO-CTA).Methods A total of 691 patients with acute chest pain who underwent TRO-CTA exami-nation from multiple centers were prospectively selected and randomly divided into mixed group and unmixed group according to dif-ferent contrast injection methods.The image quality of aorta,pulmonary artery and coronary artery in the two groups was evaluated subjectively and objectively and the radiation dose was calculated.Results There were no significant differences in subjective image quality scores,aorta and coronary CT values,signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)between the two groups(P>0.05),while there were significant differences in pulmo-nary CT values,SNR,CNR and radiation dose between the two groups(P<0.05).Conclusion The utilization of a mixed contrast injection scheme in TRO-CTA can satisfy diagnostic require-ments while ensuring a low proportional dosage and reduced radiation dose,which has clinical application value.

Objective To investigate the feasibility of CT pulmonary angiography (CTPA) with 80 kVp and contrast agent of iodixanol (270 mg I/ml) by filtered back projection(FBP) reconstruction.Methods In total,52 patients who underwent CTPA were randomly divided into two equally-sized groups,control group and experimental group.The volume computed tomography dose index (CTDIvol) and dose-length product (DLP)were recorded,and the weighted computed tomography dose index (CTDIw) and effective dose (E) were calculated.The image quality was visually evaluated and measured,and statistical analyses were performed on the image quality and the radiation dose.Results The sex,age,height,weight and body mass index (BMI) had no statistical difference between two groups (P ＞ 0.05).The average iodine dosage decreased by 22.9％ in the experimental group compared with the control group.Compared with the control group,the CTDIvol,DLP,CTDIw and E decreased by 73.5％,75.1％,73.5％ and 75.8％,respectively.The differences were statistically significant (t =＜0.001,30.5,＜ 0.001,-28.7,P ＜ 0.05).The image quality of the two groups met the requirement of diagnosis and there were no significant statistic differences between visually evaluating and objectively measuring the image quality (P ＞ 0.05).Conclusions Using 80 kVp and iodixanol for CTPA,FBP reconstruction image quality can meet diagnostic requirements.At the same time the radiation dose,the contrast agent dose and the X-ray tube wastage are reduced respectively.

The contents of cholesterol in a number of vegetable oils were determined by saponification-gas chromatography ( FID) . There was quite a large possibility that cholesterol peak was seriously interfered by saponification-gas chromatography ( FID) , so it was difficult to set a cholesterol content value to differentiate vegetable oil from waste oil. Solid phase extraction ( SPE) sample pretreatment was chosen and the process conditions were optimized. The optimal conditions were as follows:0. 25 g of oil samples, 20 mL of 0. 6%ethyl ether-hexane ( V/V) as eluent ( get rid of fatty acid glycerides) and 20 mL of 15% ethyl ether-hexane ( V/V) as eluent ( obtain cholesterol) . An obvious cholesterol-content-difference between vegetable oils and waste oils was found by SPE-GC. The detected cholesterol contents in 84 vegetable oil samples were all less than 50 μg/g and the contents of 11 waste oil samples among the 13 waste oils were greater than 50 μg/g. Therefore, cholesterol content in vegetable oil of more than 50 μg/g could be determined as suspected waste oil, not vice versa by SPE-GC. The correlation coefficient R2 was 0. 9999 in 0-760 mg/L concentration range, and the detection limit was 6. 0 μg/g. Relative standard deviations at two concentration levels of 17. 7 and 695 mg/L were 1. 6% and 1. 5% respectively. The recovery was 103%.

ObjectiveTo investigate the value of 64-slice CT urography (CTU) in diagnosis of urologic diseases.Methods Sixty patients with suspected urinary system diseases underwent 64-slice CT volume scanning and 3D reconstructions.The diagnostic value of 64-slice CTU was evaluated.ResultsThere were 14 patients with urinary system cancers,2 with ureter polyp,9 with tuberculosis of urinary system,13 with urinary system calculus,13 with nonmalignant ureterostenosis combined with hydronephrosis,2 with ureterostenosis and hydronephrosis induced by nearby organic damage,2 with traumatism,1 with renal occlusion,as well as 4 after urinary tract surgeries and 2 without abnormality.Totally 28 cases was confirmed with surgery and pathology,the sensitivity,specificity and accuracy of MSCTU for upper tract tumor was 100％(14/14),85.71％ (12/14) and 92.86％ (26/28),respectively.ConclusionMSCTU is able to directly and clearly show urologic diseases.It can be regarded as the first choice in patients with clinically suspected urinary tract diseases,especially tumors.

Objective To investigate imaging parameters on low field MRCP and to optimize the quality of images.Methods MRCP in 77 cases were performed using Airis-Ⅱcomfort open 0.3T low field MR imaging system made by HITACHI company.3D-FSE combined with 2D single-shot breath-hold FSE sequences were used.The 3%～5% compound solution of Gd-DTPA was taken to restrain the hige signals from remaining liquid in stomach.Results MRCP examination was succeeded in all 77 cases and the images in all cases but 2 were fine for diagnosis.The total diagnostic accuracy was 79.2%.The accuracy of MRCP in the detection of the degree and location of pancreaticobiliary duct obstruction was 100%. Conclusion The distinct MRCP images can be obtained with low field MR system using combination of several scanning techniques and proper scanning parameters,and also patients have to prepare fully.

Objective To evaluate the diagnostic value of MRI in hepatic echinococcosis.Methods MRI features of 37 cases with hepatic echinococcosis proved by operation and pathology were analysed in comparison with that of CT.Results The hepatic echinococcosis could be divided into five types according to the manifestations of CT and MRI:simple cyst in 8 cases,multiple daughter cyst in 13 cases,ruptured cyst in 7 cases,consolidated and calcified cyst in 4 cases and mixed cyst in 5 cases.Conclusion MRI can clearly show and determine the location,size,form,number and types of hepatic echinococcosis,that are helpful for the plan of operation.

Objective To evaluate the diagnostic value of the low field MRCP in obstructive jaundice by comparing its result with that of US and CT. Methods 55 cases of obstruction jaundice patients proved by clinical diagnosis were studied and compared the collected original diagnosis results by low filde MRCP with US and CT.Results Of 55 cases of obstructive jaundice, 30 were cholelithiasis ,21 were tumors and 4 belonged to the other type. The accuracy of MRCP for defining the site of obstruction was 100%. The accuracy for identifying the cause of obstruction was 81.8%.Conclusion The low filde MRCP can accurately define the obstructive site in biliary obstructive disease .When used together with 2D single-shot breath-hold MRCP , T 2WI, T 1WI and 3D-FSE MRCP shows high accuracy and sensitivity in diagnosing obstructive jaundice.