Objective To evaluate the effect of different tube voltage and noise index (NI)on image quality and radiation dose during peripheral artery CTA with automatic tube current modulation(ATCM)technique.Methods Seventy-two patients were ran-domly divided into three groups with different scanning tube voltage and noise index as follows:group A with 100 kV and NI of 1 5, group B with 80 kV and NI of 1 5,group C with 100 kV and NI of 20.Image quality,segmental vascular enhancement,signal-to-noise ratio (SNR),contrast-to-noise (CNR)and effective dose (ED)were independently evaluated in 3 groups.The methods of sta-tistics analysis were ANOVA,and P <0.05 represented the significant difference.Results There was no significant difference of image quality of the peripheral artery among 3 groups.The CT value,SNR,CNR in group B (80 kV)was the highest,and there were statistical differences between A,B groups and B,C groups of arteries (P <0.05),and there was no satistiacal difference between A group and C group.Compared with group A and group B,the CTDlvol,DLP and ED of group C was reduced 50.45%,51.20%,51.21% and 35.03%,34.91%,34.92%,respectively,and the difference was statistical significance (P < 0.05 ),and there was no significant difference between group A and group B (P >0.05).Conclusion Using ATCM low-kV with high NI scanning can reduce radiation dose without interference on image quality for peripheral artery CTA.

Objective To evaluate the clinical value of computed tomography (CT) examination in the etiologic diagnosis of small bowel obstruction.Methods From January 2010 to September 2013,a total of 237 patients with small bowel obstruction confirmed by operation were enrolled.The clinical data of all patients were collected.The diagnostic value of color Doppler ultrasound and abdominal CT examination were compared in estimating site of obstruction,etiology of obstruction and strangulation obstruction.Chi square test was performed for count data comparison.Results Among 237 patients with small bowel obstruction,there were 121 patients with data of both color Doppler ultrasound and abdominal CT examination.After operation,it was comfirmed that the accurate diagnosis rates of abdominal CT scan in the site of obstruction,the etiology of obstruction and strangulation obstruction were 75.2 ％ (91/121),66.1％ (80/121) and 87.2％ (41/47),respectively,and which were higher than those of abdominal color ultrasound (44.6％,54/121; 30.6％,37/121 and 42.6％,20/47).The differences were statistically significant (x2 =23.555,30.595 and 20.593,all P＜0.01).Conclusion The accurate diagnosis rates of abdominal CT scan in estimating the site of obstruction,the etiology of obstruction and strangulation obstruction were higher than those of color Doppler ultrasound,especially with obvious advantage in judging the etiology of obstruction.

Objective To discuss the diagnostic value of monochromatic energy image spectral CT in active small bowel bleeding and to screen the optimal energy level that indicates active bleeding of the gastrointestinal tract.Methods The bleeding model was established using the small intestines of pigs in vitro.Seven blood flow rates were simulated:0.500,0.400,0.300,0.200,0.100,0.050,0.025 ml/min,respectively.For each rate,a GE Discovery HD750 CT scanner was used in GSI scan mode and 64 slice CT was performed,with a delay of 15 s and 40 s simulated the arterial phase and portal venous phase,respectively.Each out of the blood flow rate in the 2 modes was respectively scanned 5 times.The GSI reconstruction platform was employed to obtain 7 monochromatic energy images(40,50,60,70,80,90,100 keV).A set of polychromatic energy images was obtained from an ordinary scan.The detection rates of the contrast agent exudation regions using the two scanning methods were compared.The contrast to noise ratios(CNR) for the contrast agent exudation regions were measured.Randomized block analysis of Variance was performed to compare the differences in CNR between energy levels.The x2 test was used to compare the detection rates obtained from the 2 scanning methods.Results The detection rates for energy spectral CT and 64 slice CT in the arterial phase were 31/35 and 23/35,respectively; there was significant difference(x2=5.185,P=0.023).The total detection rates of portal venous phase were 35/35 and 32/35,respectively,there was no significant difference(x2=l.393,P=0.238).On the ordinary scan mode,the detection rates of arterial and portal venous phase difference was statistically significant(x2 =6.873,P =0.009);but on the GSI scan mode,there was no significant difference(x2=2.386,P=0.122). The CNR values at 8 group energy levels for arterial phase and portal venous phase were statistically different(respectively P＜ 0.05),the CNR value of the contrast agent exudation regions at 50 keV and 60 keV monochromatic energy images on the GSI scan mode higher than that of polychromatic energy images,the difference was statistically significant(respectively P＜0.05),the CNR in portal venous phase images were higher than that of arterial at all energy groups,differences were statistically significant(t=-3.996 to-2.380,respectively P＜ 0.05).Conclusions Monochromatic energy image spectral CT demonstrates superiority over polychromatic energy images in detecting active bleeding of the gastrointestinal tract.The optimal monochromatic energy value for detection was between 50 keV and 60 keV,and the detection was easier in the portal venous phase than in the arterial phase.

Gastrointestinal duplication cyst is a rare congenital disease which can occur in any part of the digestive tract between the root of tongue and the anus,and it is commonly seen in the ileum.About 45％ of the gastrointestinal duplication cyst occurs in the ileocecus and the epityphlon.Multiple gastric duplication cyst is a rare type of the gastrointestinal duplication cyst,which accounted for 3.8％-5.0％.Gastric duplication cyst mostly occurs in the greater curvature of the stomach,and it connects with the stomach wall.Multiple gastric duplication cysts in the mediastina is rarely seen.In this article,the imaging presentations of 1 patient with multiple gastric duplication cysts inside the mediastina were analyzed.

Objective To study the clinical value of 64-slice spiral computed tomography(64SCT) contrast-enhanced scan and three-dimensional reconstructed techniques in the diagnosis of complex congenital heart disease(CCHD). Methods 39 patients with CCHD underwent CT angiography and transthoracic echocardiograms (TTE). Of them, the electrocardiographic-gating technique was used in 8 cases. The accurate rates in diagnosing CCHD with CT, TTE and CT with or without electrocardiographic-gating were analysed compared with that of operation and χ~2 test using SPSS13.0 tool. Results A total of 102 cardiac deformities con-firmed by operations,those included 47 intracardiac deformities,the diagnostic accuracys with CT and TTE were 85.1% and 95.7%, respectively, and there was no obvious difference among them (χ~2=2.68, P>0.05). 55 extracardiac deformities, the definite diagnos-tic rates with CT and TTE were 98.2% and 78.2%, respectively. CT was superior to TTE in the indentification of extracardiac de-formities(χ~2= 14.64 ,P<0.01). There was no obvious difference between with and without electrocardiographic-gating technique during CT scanning in diagnosis of cardiac deformities(χ~2=1.84, P>0.05). Conclusion 64SCT has significant value in diagnosis of CCHD,and there was no obvious difference in diagnosis of cardiac deformities by 64SCT between with and without electrocardio-graphic-gating technic.

Objective To explore the value of gemstone spectral imaging (GSI) in the detection and differential diagnosis of benign and malignant thyroid nodules.Methods The spectral CT images in 88 patients with thyroid nodules were analyzed retrospectively.All the patients underwent spectral CT scanning,including 33 patients undergoing biphase enhanced CT imaging.Nodules were divided into benign and malignant ones according to histopathologic results.The iodine concentration,slope of spectral curve,effective atomic number in non-enhanced and enhanced scanning were compared between benign and malignant group by the Wilcoxon rank sum test,respectively.The optimal iodine concentration threshold to predict malignancy was obtained by receiver operating characteristic curve (ROC),sensitivity and specificity were achieved.Results A total of 106 nodules were detected,including 76 benign and 30 malignant nodules.In non-contrast CT imaging,the average iodine concentration,slope of spectral curve,effective atomic number of were 2.35 × 100 μg/ml,0.29 and 7.71 for benign group:-0.51 × 100 μg/ml,-0.06 and 7.52 for malignant group (Z value were-3.072,-3.107 and-3.055,respectively ; P ＜ 0.05).In the arterial phase,the average iodine concentration,slope of spectral curve,effective atomic number of the two group were 27.22 × 100 μg/ml,3.23 and 9.10 for benign group; 18.81 × 100 μg/ml,2.24 and 8.69 for malignant group (Z value were-2.582,-2.582 and-2.564,respectively; P ＜ 0.05).In venous phase,no significant difference was found for each parameter between the two groups (P ＞ 0.05).The optimal iodine concentration to predict malignancy was-0.35 × 100 μg/ml in non-enhanced phase with 56.7％ sensitivity and 73.7％ specificity.The optimal iodine concentration was 22.91 × 100 μg/ml in arterial phase,with 76.2％ sensitivity and 75.0％ specificity.Using iodine concentration to predict malignancy in both noncontrast phase and arterial phase,the sensitivity and specificity were 81.2％ and 73.3％,while the accuracy was 81.6％.Conclusion Gemstone spectral CT imaging can quantitatively evaluate the iodine content of thyroid nodules,having a potential value in differential diagnosis of thyroid nodules.

Objective To evaluate the techniques and application of 64-slice helical CT colonography in colonic lesions. Methods Thirty-eight patients (including 12 colonic carcinomas,10 polypi, 9 colon multiple scrobiculus, 2 multiple diverticula, 2 negative, 1 congenital bowel malrotaion,1 ulcerative colitis and tunica mucosa glandular organ hyperplasy,1 colocolic anastomosis of terminal ileum and sigmoid colon) underwent volume scanning using 64-slice helical CT after cleaning colon. Six types of reconstruction including CT virtual colonoscopy(CTVC), volume rendering(VR), multiple planar reconstruction(MPR), 360?sectional view, RaySum,and navigation were gained.CTVC appearances were compared with that of conventional colonoscopy(CC).Results In 12 colonic carcinomas and 10 polypi,the lesions’ morphology,number,size, were satisfactorily shown by CTVC. The lesions’ location,range,and 1 intestinal canal obviously stenosis were also exactly shown by RaySum.The relationship between tumor and environment, 3 liver or retroperitoneal lymph node metastasis were satisfactorily shown by MPR and 2D transection image. On 360?sectional view,the distance between tumor and anus was exactly measured and the result was in conformity to that of CC. Of the CTVC appearances,1 sigmoid carcinoma and 1 transverse colon polyp was in unconformity to that of CC;1 ulcerative colitis and descending colon carcinoma was diagnosed as ulcerative colitis and tunica mucosa glandular organ hyperplasy by pathology.Conclusion 64-slice helical CT is a valuable imaging technique for detecting colon diseases. CTVC can obtain more clinical information than CC combining MPR,RaySum and VR.

Objective To study the influence of various doses and injection rates of contrast agent on CT perfusion in rabbits' liver with a deconvolution mathematical model. Methods Eight rabbits were enrolled in the experiment. Randomized block design was adopted. The treatment factor (contrast medium injection rate) was classified into 0.5, 1.0, 1.5 ml/s, while the subjects were divided into 3 blocks with contrast medium injection dose of 0.5, 1.0 and 1.5 ml/kg. The data obtained at CT perfusion imaging were then transferred to the workstation. Absolute values of 7 perfusion parameters (hepatic arterior fraction, blood flow, blood volume, permeability surface, mean transmit time, hepatic artery perfusion and portal vein perfusion) were measured with perfusion software (Perfusion 3). Results The dose of contrast medium had significant effect on peak enhancement of the aorta, the portal vein and liver tissue (P<0.05), whereas the injection rates had significant influence on the arrival time to peak enhancement of the aorta and the portal vein. However, the dose of contrast medium and injection rates had no significant effect on perfusion parameters (P>0.05). Conclusion CT perfusion imaging with a deconvolution mathematical model can quantify the hemodynamic functional status in liver with stable results. This technique does not need strict confinement to dose and injection rate of contrast medium, and has great potential value to be put into clinical use.

Objective To evaluate the value of multi-slice CT enterography(MSCTE),capsule endoscopy(CE) and contrast-enhanced ultrasound(CEUS) findings score in the assessment of Crohn disease activity,prospectively.Methods One hundred and eight patients were diagnosed with CD by endoscopy combined with clinical or pathological results,and all of the patients' Crohn disease activity index(CDAI) were greater than or equal to 150.MSCTE were performed in all the patients.At the same time,48 and 60 patients of them were voluntary to accept CEUS and CE examination,respectively.The imaging score of the three different techniques was calculated.Patients' CDAI were calculated combined with the C-reactive protein(CRP) content and clinical feature.To analyze the correlation among the imaging score patients' CDAI,and CRP content,respectively using the Pearson method.Results The mean score of MSCTE,CEUS and CE were(7.6±2.7),(11.5 ±4.3) and(12.8±8.2),respectively.The patients' mean CDAI and CRP content were(296.1±93.5) and(23.7±5.2) mg/L,respectively.It was high correlation between MSCTE score and CDAI (r=0.916,P＜0.01),but it was moderate between CEUS(r=0.752,P＜0.01),CE(r=0.707,P＜0.01) score and CDAI.There was no evident correlation between MSCTE(r=0.167,P＞0.05),CEUS(r=0.200,P＞0.05) score and CRP content excepting the CE result(r=0.467,P＜0.01).Conclusions There was a good correlation between the MSCTE score and CDAI.We could use MSCTE findings score to assess the activity of CD patients prospectively.

This study was aimed to establish the method of identifying bupleurum cultivated germplasm using simple sequence repeat (SSR) molecular markers and to initially establish dataset of characteristic SSR bands to the bred cultivars or strains. From the bupleurum SSR primer pairs which were designed in previous work, 50 primer pairs were selected. Two bred strains and 4 other bupleurum cultivated germplasms were used as test materials. Primers pairs were screened with effective PCR amplification and high polymorphism. Meanwhile, conditions for PCR amplification and electrophoresis were optimized. Then, obtained SSR bands were analyzed and a clustering tree on the basis of genetic distance was constructed. The results showed that 9 SSR primer pairs can be used for identification. The suitable assay conditions were established and characteristic SSR bands were obtained for tested materials. The tested samples can be divided into 4 categories in the genetic similarity coefficient of 0.73. TheB. scorzonerifolium cultivated inHeilongjiang andChuanhongchaiNo. 1 strains were clustered as one category. ChuanbeichaiNo. 1 strain andZhongchai No. 1 cultivar clustered as another category. Cultivated germplasms fromSichuan Fengshunand Rongxian clustered as a unique category. It was concluded that the primer pairs and assay method established in the present study can be used as reference in identification of bupleurum cultivars or cultivated germplasms.