Objective To evaluate the main scanning technique and clinical value of 16-slice spiral CT coronary angiography(CTCA).Methods Plain and enhanced imaging were performed by retrospective ECG gating in 76 patients,including 65 cases suspected coronary artery disease,8 cases of coronary stent and 3 cases of coronary bypass graft.Post-processing was conducted with VesselView soft package,in which MPR,MIP,VRT and section plane of conoray artery were made in all cases,among them 35 cases underwent selective coronary angiography(SCA) as a comparision.These main segments(vessel diameter≥2 mm) in CTCA were compared with SCA,and≥50% reduction of vessel diameter was defined as significant disease.Results 85.1% of the coronary segments in CTCA were accessible and could accurately displaye the patency of the coronary arteries and the pathological changes in vessel walls.In comparison with SCA,the sensitivity and specificity were 86.5% and 95.1% respectively. When 46 coronary artery segments judged unevaluable were included in the analysis,the sensitivity was 78.0%(32/41).Conclusion 16-slice CTCA can display long segment of coronary artery and assess coronary artery disease with high accuracy,which has highly clinical value.

Objective To investigate the performance of dual source CT scanning combined with low-tube-voltage iterative reconstruction (SAFIRE) for demonstrating coronary artery calcium plaques. Methods 70 patients with clinically suspected coronary atherosclerosis and with normal BMI received SAFIRE-3 or filtered back projection (FBP) for reconstruction after undergoing CT scans with tube voltage range of 100 kV. The CT images (average CT values, noise, SNR, and CNR) and subjective scores (number of calcium plaque, calcium plaque adjacent artifacts, and image quality) were compared between the two groups. Results The average CT value of the aortic root did not differ significantly between the two procedures for reconstruction (P > 0.05). Ob jective evaluation of the images (noise, SNR, and CNR) between the two groups was statistically significant (P < 0.05 for all comparisons), so was image subjective rating (number of calcium plaque and rate of calcium plaque edge)(P < 0.05 for all comparisons). SAFIRE-3 reconstruction was markedly superior to FBP reconstruc-tion. Conclusions Low kilovoltage combined with reconstruction of SAFIRE-3 can reduce calcium plaque adja-cent artifacts and enhance quality of images , which is better than FBP in displaying the morphology and adjacent conditions of calcified plaque; therefore it is worth popularizing.

Objective Based on the teeth in vitro skull specimen to investigate the feasibility and accuracy of CARE kV CT scan for reducing radiation dose. Methods Of eight fixed and preserved skull teeth were scanned repeatedly in groups of A, B, C. In expose factors of 100 kVp/150 mAs in conventional scanning of group A, open CARE Dose 4D scan of group B and CARE kV scan of group C. We assessed the radiation dose in the group A, B and C, the average CT values of the images, noise, SNR, CNR and subjective ratings. Results Three groups of actual scan tube current, tube voltage and radiation dose were statistically significant (P < 0.05). Compared with group A, the radiation dose in the group B was reduced by about 13.76% and 26.61%reduced in the C group. The average CT values of the images and the noise SNR, CNR and subjective ratings hasd no significant difference (P > 0.05). Conclusion CARE kV technology based on the use specimens tooth can reduce the radiation dose, protect image quality, and be consistent to the reports of previous researches.

Objective To explore the optimized scanning parameters of low-dose un-enhanced chest CT with sinogram affirmed iterative reconstruction (SAFIRE).Methods Eleven healthy adult domestic dogs underwent chest scanning of 120 kV,100 kV,80 kV,70 kV with a fixed tube current of 65 mA and halved tube current of 32 mA with a fixed tube voltage of 100 kV.The data were reconstructed with filtered back projection (FBP)and SAFIRE (strength grade 3)respectively to obtain ten groups of images.The regular dose (120 kV/65 mA ) combining with FBP reconstruction was as normal control group,and other groups as experimental groups.CT dose index (CTDI), dose length product (DLP),and effective dose (ED)at different dose were compared,and average CT value,noise,signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR)and image quality score of ten groups of images were comparatively analyzed.Results No significant differences were found in average CT value for lung tissue,the superior vena cava,the aortic arch,and spinal muscles among ten groups (P >0.05),except adipose tissue (P <0.05).Compared to the control group,radiation dose of the 100 kV/65 mA-SAFIRE group decreased by 40.00%,noise of this group reduced,SNR and CNR increased,image quality score was slightly higher.Radiation dose of 80 kV/65 mA and 100 kV/32 mA groups,compared to the control group,decreased by 71.33% and 70.00% respectively ;image quality was slightly degraded but the subjective image quality scores were above 4 ,which on the latter group was slightly higher than that on the former.Image quality of 70 kV/65 mA group was reduced but could meet the requirements of diagnosis (image quality score >3),and the radiation dose of this group decreased by 81.33%.Conclusion Reconstructed with SAFRIE technology,the image quality of 100 kV/65 mA scanning of chest CT is similar to that of routinely reconstructed images in regular dose,while the image quality of 70 kV/65 mA scanning can not only meet the requirements of diagnosis but also obviously reduce radiation dose.

Objective To make spinal cor injury model of rabbit in order to investigate the feasibility and accuracy of diffusion tensor imaging in diagnosis of early ASCI. Methods In 30 Chinese rabbits ,24 rabbits were randomly selected as the experimental group and the other 6 as the control group. Allen′s technique were used to make moderateacute spinal cord injury in the experimental group. In the control group ,the operation only exposed the spinal membrane ,wihthout damage on the spinal cord. All rabbits were performed in routine MRI , DTI ,diffusion tensor tractography and post-processing. After the MRI scan ,the rabbit spinal cord was removed to have pathological examination at 1 ,3 ,5 ,7 days. Results The number of inflammatory cells and spinal motor neurons were closely correlated with FA values and ADC values. DTT images showed the spinal cord defects, curling and breaking. Conclusion The parameters of DTI (FA ,ADC) can reflect the pathological changes of acute spinal cord injury in early stage ,and therefore may be used as an routine evaluation method for clinical acute spinal cord injury.

Purpose To study the MRI manifestations of hippocampus with acute injury in children with epilepsy, and to explore its causes and outcomes for a better understanding of the changes of hippocampal structure with acute injury.Materials and Methods The clinical and imaging data of 8 children with epilepsy whose hippocampus showed hyperintensity in DWI were retrospectively analyzed. The bilateral hippocampal volume and ADC values were measured; changes of hippocampal volume and T2WI signal and ADC value were also analyzed.Results Eight patients were clinically diagnosed as epilepsy, 7 cases had recurrent history of seizures. MRI was performed from 1 to 5 days after the onset of epilepsy. All the 8 patients had increased unilateral hippocampal volume, 6 of whom were on the left side and the other 2 were on the right side. The affected ipsilateral hippocampal volume was significantly higher than that on the contralateral side [(2.096±0.570) cm3 and (1.768±0.447) cm3, respectively,t=-4.763,P<0.01]. The signals increased on T2WI and FLAIR; DWI showed hyperintensity with increase by approximately 25.52%. The affected ipsilateral ADC value was significantly lower than the contralateral one [(0.763±0.049)×10-3 mm2/s and (0.859±0.054)×10-3 mm2/s, respectively, t=9.598,P<0.01]. No abnormalities were found in bilateral hippocampus when 3 patients underwent MRI due to febrile convulsions and seizures before the onset of epilepsy. The affected ipsilateral hippocampal volume reduced in 3 patients after 3 to 5 months;signal was still high on T2WI and FLAIR; ADC values increased by 15.6%, the imaging results indicated hippocampal sclerosis.Conclusion Epilepsy can cause acute injury in hippocampus which demonstrates hippocampus swelling, signal increase on T2WI, and reduced ADC value and may lead to hippocampal sclerosis.

Objective To establish normal kidney data by measuring the diameter and volume of the kidneys in a -dult Guizhou miniature pig.Methods Twelve healthy adult Guizhou miniature pigs (male 6, female 6) were used in this study.The kidneys were scanned by using Siemens dual source CT , and the raw data were used for multiplanar reconstruc-tion (MPR) and volume reconstruction (VR) using the software Aquarius iNtuition 4.4.The anteroposterior and left to right dimensions of both kidneys were measured at the median transverse plane of the organ , and the long and short diame-ters of both kidneys were measured at the maximum coronal section of the organ .The volume of both kidneys and miniature pig itself, the ratio of long to short diameters of both kidneys , and the relationship between the ratio of long to short diame-ter and the kidney were calculated .The correlation between the length dimension , length diameter ratio and the volume of the kidney was analyzed , and the correlation between volume of the kidney and miniature pig was analyzed as well .P<0.05 was set as statistically significant .Results The dimensions of anteroposterior , left to right, long and short diameters of left kidney were 40.40 ±1.67 mm, 27.47 ±1.40 mm, 80.36 ±2.74 mm and 31.79 ±1.99 mm, respectively.The vol-ume of left kidney was 52.78 ±2.25 cm3 , and the ratio of long to short diameter of the left kidney was 2.42 to 2.71:1. The dimension of anteroposterior , left to right, long and short diameters of the right kidney were 40.95 ±1.43 mm, 26.90 ±0.65 mm,79.03 ±2.38 mm and 32.04 ±2.34 mm, respectively .The volume of right kidney was 51.91 ±2.25 cm3 , and the ratio of long to short diameter of the right kidney was 2.33 to 2.77:1.There were highly positive and significant correlations between the long diameter and the kidney volume (rleft =0.92, P<0.05;rright =0.88, P<0.05) as well as between the kidney volume and the miniature pig (rleft =0.96, P<0.05;rright=0.98, P<0.05), while the ratio of long to short diameter of the kidney was negatively related to the volume of the miniature pig ( rleft =-0.51, P<0.05;rright=-0.67, P<0.05).Conclusions Multislice spiral CT and its post-processing software can accurately measure various data of the kidneys of Guizhou miniature pig in vivo , providing normal reference of the animal model for the research of hu -man kidney diseases .

Objective To investigate the feasibility of chest examination using ultra-large pitch Turbo Flash in Force CT in preschool children without sedative.Methods A total of 90 preschool children evaluated as nervous or frightened were equally divided into 3 groups according to the scanning time.For group A,the routine scan with the mode of CARE Dose 4D/CARE kV was performed,and the sedative was used.For group B,the scan with ultra-large pitch Turbo Flash model and pitch as 3.0 was performed,and the sedative was used.For group C,the same scan mode as group B was performed but without sedative.The scanning time,radiation dose,image quality and the diagnostic efficiency were compared among 3 groups.Results There were no significant differences of the CT values of the aorta root,spinal posterior muscles and subcutaneous fat,the noise of the aorta root,SNR and CNR among 3 groups (all P＞0.05).Moreover,no significant differences of the subjective score of image quality in pulmonary window and mediastinum window images were found among 3 groups (both P＞0.05).The scanning time and radiation dose indexes (CT dose index volume [CTDIvo1],doselength product [DLP],effective dose [ED]) of group A were significantly higher than those of group B and group C (all P ＜0.05),while there were no significant differences between group B and group C (all P＞0.05).There were no significant differences between the CT diagnosis and clinical diagnosis results in all 3 groups (all P＞0.05).Conclusion It can shorten the scanning time and decrease the radiation dose by using the mode of ultra-large pitch Turbo Flash.And the satisfactory image quality can be obtained without sedative for nervous or frightened preschool children.

Objective To investigate the diagnostic value and limitations of dual-energy virtual non-con-trast images of dual-source CT in common benign liver diseases. Methods Dual-source CT was performed on 226 upper abdomen pathogenesis patients. The conventional non-contrast (CNC) scan was performed with single-energy mode, the arterial phase and portal phase scans were performed with dual-energy mode. The virtual non-contrast (VNC) images were derived from the portal data using liver virtual non-contrast software. 117 patients with common benign liver diseases were retrospectively analyzed in CNC and VNC. The lesion detectability, effective radiation doses for single-energy mode and dual-energy mode were compared. Results Among 117 patients, there were 28 (73.6%) hemangiomas, 58 (85.3%) calcifications or stones in VNC, but the hemangiomas, calcifications or stones in CNC were 37 (97.3%) and 68 (100%), respectively. The hemangiomas, calcifications or stones in VNC and CNC were significantly different (P < 0.05). The detection of cyst and hepatic steatosis on VNC images were similar as CNC(P > 0.05). The CTDIvol, DLP and ED of dual-energy mode were obviously lower than those of single-energy mode (P < 0.05). Conclusion The detection of hemangiomas, calcifications or stones on VNC images is lower than CNC images. There is no difference in detecting cyst and hepatic steatosis. In addition, radiation dose will be reduced due to adopting VNC.VNC has potential clinical application value.

Objective To investigate the difference of morphology and blood flow of cavopulmonary anastomosis by MRI and that by ultrasonic cardiography (UCG) in patients with bidirectional Glenn shunt (BGS).Methods Phase-contrast MRI (PC-MRI) and contrast enhanced MRI (CE-MRI) were performed for superior vena cava ( SVC ) and inferior vena cava (IVC) in 22 patients with BGS on 3.0 T MR scanner.PC-MRI was used for measuring blood flow and CE-MRI for illustrating morphology.The width,peak flow velocity and gradient pressure of cavopulmonary anastomosis were calculated by using Report Card software.The similar data of UCG was collected.The parameters by MRI and that by UCG were compared statistically by t test and Pearson correlation.Results Based on the MRI data,the blood flow of SVC [ ( 1.002 ±0.208) L/min ] was significantly lower than that of IVC [ ( 1.794 ± 0.392 ) L/min ] ( t =- 15.148,P ＜0.01 ),while the regurgitation fraction of SVC [ (26.54 ± 12.82)％ ] was significantly higher than that ofIVC [ ( 17.44 ± 10.17)％ ] (t =11.060,P ＜0.01 ).The morphology displayed with MRI angiography couldnot be detected with UCG.The width of cavopulmonary anastomosis measured by MRI [ (12.46 ±3.43 ) mm ] was significantly higher than that of UCG[ ( 11.04 ± 2.63 ) mm] ( t =4.048,P ＜ 0.01 ),while the peak flow velocity of cavopulmonary anastomosis measured by MRI [ (47.77 ± 10.44) cm/s] was significantly lower than that of UCG [ (52.19 + 9.63) cm/s] ( t =- 2.237,P ＜ 0.05 ).No significant difference was found in gradient pressure of cavopulmonary anastomosis between the values by MRI [(0.95+0.42) mm Hg(1 mm Hg =0.133 kPa)] and that by UCG [(1.12+0.38)mm Hg] (t=2.010,P ＞ 0.05).The width,peak flow velocity and gradient pressure of cavopulmonary anastomosis by MRI were closely correlated with those by UCG (r =0.858,0.489,0.427,all P＜ 0.05 ).Conclusions A good correlation is found in the width,peak flow velocity,and gradient pressure of the cavopulmonary anastomosis obtained by 3.0 T MRI and UCG.MRI is more useful tool to display the width and abnormal morphology of cavopulmonary anastomosis than UCG.