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Objective To compare the iodine intake,image quality and radiation dose of dual-source CT coronary artery angiography between the low concentration isotonic contrast agent with iterative reconstruction technique of sinogram affirmed iterative rEconstruction (SAFIRE) and common concentration contrast agent with filtered back projection (FBP).Methods One hundred patients [58 men,42 women; age:(62± 11)y] were enrolled in this study.Fifty consecutive patients (Group A) were scanned with FBP and common concentration contrast agent and another 50 consecutive patients (Group B) were scanned with low concentration isotonic contrast agent and iterative reconstruction technique.The image quality were assessed by two experienced radiologists with a double blinded fashion in a five score scale.The attenuation of coronary artery,scan time,imaging noise,signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR),radiation dose and iodine intake between these two groups were compared using two sample t test.The observer agreement for image quality was calculated using Kappa statistics.Results All examinations were completed successfully.There was no statistical difference (P＞0.05) between two groups in clinical characteristics and scan parameters.There was no statistical difference for the mean subjective image quality of group A (4.4±0.7) and group B (4.3±0.8) (t=0.924,P＞0.05).The Kappa value between two radiologists was 0.887 (P＜0.01)on image quality.The mean attenuation of coronary artery segments was higher than 300 HU,especially in group A (386.1±51.5) HU,which was slightly higher than the group B (384.1±77.1) HU,but there was no statistical difference (t=0.157,P＞0.05).The SNR and CNR in two groups did not have significant differences (P＞0.05).The total iodine and iodine injection rates were 21.0 g,17.5 g/s in Group A and 16.2 g,13.5 g/s in Group B,respectively.The iodine intake was decreased by 22.9％ in Group B.The effective radiation dose in Group B (1.09±0.19) mSv was significantly (t=20.260,P＜0.01) lower than that in Group A (2.85±0.59) mSv,with the radiation dose reduced by 61.8％.Conclusion Low concentration isotonic contrast agent and iterative reconstruction technique can significantly reduce the radiation dose and iodine intake in CT coronary artery angiography and achieve the same image quality using common concentration contrast agent with FBP.
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The present paper is aimed to study the preparation and application of individual artificial bone of carbon/carbon composites. Using computer tomography images (CT), we acquired a three-dimensional image. Firstly, we described bone contour line outlined with manual and automatic method by the binary volume data. Secondly, we created 3D object surface information by marching cubes. Finally, we converted this information to non-uniform rational B-spine (NURBS) by using geomagic software. Individual artificial bone with carbon/carbon composite was prepared through the CNC Machining Center. We replaced the humeral head of the tested rabbit, and then observed the effects of implantation in neuroimaging and pathological section. Using this method, we found that the bone shape processed and bone shape replaced was consistent. After implantation, the implant and the surrounding bone tissue bound closely, and bone tissue grew well on the surface of the implant. It has laid a sound foundation of the preparation using this method for individual artificial bone of carbon/carbon composite material.
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Animals , Rabbits , Bone Substitutes , Chemistry , Carbon , Chemistry , Imaging, Three-Dimensional , Software , Tomography, X-Ray ComputedABSTRACT
Objective To explore the accuracy and radiation dose of the right ventricular analysis with DSCT(dual-source computed tomography)using dual-step prospective ECG trigger.Methods Fortyeight consecutive patients who were suspected or diagnosed with coronary artery disease were examined with DSCT coronary angiography and MRI ventricular analysis.Sequential acquisition and dual-step prospective ECG-trigger were used with 30％-90％ width R-R interval.Full tube current output was adopted at 70％ (HR ≤70 bpm)or 40％ (HR ＞ 70 bpm) R-R interval according to heart rates,while 20％ current output was adopted in other R-R interval.Coronary artery was divided into 16 segments according to the American Heart Association.Image quality of coronary arteries were graded with 4-points scale.The DSCT date was reconstructed with 5％ R-R interval.RVESV,RVEDV and RVEF were evaluated in DSCT and MRI.Results Forty-two cases accomplished DSCT and MRI examination.In 558 evaluated coronary segments,96.42％ could be diagnosed.The average radiation dose was(2.82 ± 0.55)mSy.Paired t-test indicated that the RVESV,RVEDV and RVEF of DSCT and MRI had no statistically significant differences (t =-0.28,0.44 and 1.49,P＞0.05),and the correlation was high (r =0.89,0.89,0.87).Conclusions The two generation DSCT with dual-step prospective ECG-triggered sequential acquisition can be used in coronary angiography and right ventricular function analysis simultaneously,which is high in imaging quality of coronary artery,reliable in right ventricular function analysis,as well as lower in radiation dose.
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Objective To explore the application of CARE kV technique in the adult chest CT and the value of reducing radiation dose.Methods Sixty-nine patients were divided into two groups by random number generators:group A(39 cases) and group B(30 cases).Group A was examined by using CARE kV technique and group B was examined at routine 120 kV.CT dose index(CTDIvol),dose length product (DLP) and effective dose (E) were compared between the two groups,and analyzed the correlation between tube voltage selection and patient body mass index (BMI) of group A was analyzed.Results The average CTDIvol [(11.00 ± 3.89) mGy],DLP[(294.05 ± 91.17) mGy·cm] and E[(4.12 ± 1.28) mSv] of group A were lower than those of group B (16.64 ± 1.20) mGy,[(475.99 ± 41.16) mGy · cm],[(6.66 ±0.58) mSv].With statistically significant difference (t =-7.653,-10.151,-10.150,P ＜ 0.05).Compared with routine 120 kV technique (group B),the CARE kV technique (group A) could reduce the total radiation dose about 38.14％.Compared obese patients(BMI≥28 kg/m2) with non-obese patients in group A and B,the mean E of non-obese patients was lower than that of obese patients in group A,which reduced the total E about 31.74％ (t =4.322,P ＜0.05),while E in group B was no significant different between non-obese patients and obese patients.Conclusions In adult chest CT,CARE kV technique can select optimum scanning voltage automatically according to the patients with different BMI and anatomical regions,which can reduce the overall radiation dose while maintaining image quality.
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Objective To study the radioseusitization effect of gold nanoparticles modified by sodium glycididazole.Methods The sodium glycididazole was connected to gold nanoparticle,in dimension of about 18 nm,that had been modified with polyethylene glycol.The nanoparticle-swallowing efficiency of lung adenocarcinoma A549 cells was observed by a scanning electron microscope.Cells were divided into four groups:sodium glycididazole group,gold nanoparticles group,sodium glycididazole-gold nanoparticles group,and no drug control group.The radiosensitivity was detected by MTT and colony formation assays.Results Sodium glycididazole-gold nanoparticles could enter the cell cytoplasm and nucleus.The concentration of 0.003 mg/ml gold nanoparticles and sodium glycididazole-gold nanoparticles had no obvious cytotoxic effect.After irradiation of 2,4,6,8 Gy,the cell survival of the sodium glycididazole-gold nanoparticle group was significantly lower than that of the other three groups (F =4.8,14.5,5.7,7.6,P ＜0.05) and the D0 and Dq values of the sodium glycididazole-gold nanoparticle group were significantly lower than those of other three groups.Conclusion Sodium glycididazole-gold nanoparticles can enhance the radiosensitivity of lung adenocarcinoma cells.
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Objective To study the image quality and radiation dose in dual-source CT cerebral angiography with prospective ECG-triggered sequence mode (step-and-shoot,SAS).Methods A total of forty-three patients with clinically suspected cerebral vascular disease underwent cerebral CT angiography with prospective ECG-triggering (step-and-shoot,SAS).Data acquisition was at 60％ R-R interval of the ECG presentation mode.The post-processing included maximum intensity projection (MIP),multiplanar reformation (MPR) and volume rendering (VR).The CTA image quality,radiation dose and rates of excellent images were evaluated.Results The CTA image quality score was 4.72 ± 0.50 and 97.7％ (42/43) patients had excellent CTA images.The average effective dose of SAS-CTA was (0.22 ± 0.01 )mSv,which was lower by 76.31％ than that of DE-CTA.Conclusions Prospective ECG-triggering sequence could be used in cerebral angiography with a significant reduction in radiation dose and diagnostic image quality.
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Objective To further investigate the accuracy of the real-time three-dimensional echocardiography(RT-3DE) in evaluating right ventricular(RV) systolic function.Methods RT-3DE,MRI and SPECT were used to study a total 30 patients including 10 with coronary artery disease,7 with hypertension,5 with cardiomyopathy,5 with atrial septal defect,and 3 with pulmonary hypertension.The RV end-diastolic volume(RVEDV),RV end-systolic volume(RVESV),RV stroke volume(RVSV) and RV ejection fraction(RVEF) were measured.The correlation and the difference between different modalities were compared.Results RT-3DE had a good correlation with MRI in RVEDV,RVESV,RVSV and RVEF (rEDV =0.811,rESV =0.837,rSV =0.818,and rEF =0.701).Also RT-3DE had a correlation with SPECT in RVEDV,RVESV,and RVSV(rEDV =0.526,rESV =0.493,rSV =0.514),but there was no correlation between RT-3DE and SPECT in RVEF (rEF =0.235).Conclusions RT-3DE can assess RV systolic function accurately.
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Objective To compare the quality and radiation doses of coronary artery angiography under the natural heart rate condition between Flash spiral heart mode and prospective electrocardiogramtriggering sequence mode using dual-source,in order to choose personalized low doses of coronary artery scanning mode.Methods Sixty patients who underwent coronary angiography(CTA)on a 128-slice,dualsource CT scanner were divided into 2 group i.e,group A(27cases)and group B(33 cases).Flash spiral heart scan mode was employed for group A.Inclusion criteria included:heart rate75 bpm),date acquisition was set at 30%-50%of the R-R interval. (3)At the arrhythmias,premature beat,fibrillation atrial,date acquisition was set at 20%-90%of the R-R interval.In both gronps,patients with a BMI≥25.0kg/m2 were examined with a tube voltage of 120 kV.while the other patients with a BMI<25.0 kg/m2 were examined with a tube voltage of 100 kV.The BMl was(24.6±1.0)kg/m2 in group A,while that was (24.6±0.9)kg/m2 in group B.In both groups,all images were transferred to the workstation for further processing and analysis.The imaging quality of coronary artery segments and the radiation dose were compared with t test.Results A total of 336 coronary artery segments were evaluated in group A and 412 segments were evaluated in group B.The imaging quality of coronary artery segments were scored.Excellent or good was achieved in 98.2%(330 of 336)artery segments in group A,and that was 98.1%(404 of 412)in group B.There was no statistical difference in imaging quality between the two groups(t=0.513,P=0.608).The average effective dose was(0.74±0.29)mSv in group A,whereas that was(3.67±1.37)mSv in group B.There was a significant difference between the two groups(t=-10.858,P=0.000).Conclusions The personalized low doses coronary artery scanning mode can substantially reduce radiation damage while preserving good imaging quality.
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Objective To analyze the clinical application of monoenergetic technique of dual-energy CT in removing metal artifacts for patients with fractures fixed with metal fixer.Methods Fofly-five patients with fractures fixed with metal fixer underwent dual-energy CT scanning for the fractures.Two different data were collected in one-time scanning using dual-energy scanning sequence.With monoenergetic technique,two different data at 100 and 140 kilovolts were used for subtraction to removing metal artifacts based on different densities.Raw data were reconstructed with monoenergetic technique(group A)and conventional simulation method(group B),respectively.And,all data were reconstructed with multiplanar reconstruction (MPR),volume rendering(VR)and maximum intensity projection(MIP),respectively.Wilcoxon signed rank test was applied for the comparison of imaging quality and artifacts between the two groups.Results There were fewer artifacts on the images due to the application of monoenergetic technique in dual-energy CT scanning.In group A,the rate of high-quality images reached to 91.9%(124/135);and,in group B,it was 59.3%(80/135).There were statistical diference between the two groups(Z=-12.541.P<0.01).The images without artifact reached to 89.6%(121/135)in group A;whereas,it was 45.2%(61/135)in group B.There was statistical difference between the two groups(Z=-11.910,P<0.01).Conclusion Using monoenergetic technique,metal artifacts were removed effectively and the fine structure of fracture was clearly displayed.
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Objective To observe the CT features of ovary Brenner tumor. Methods CT manifestations of 5 patients with ovary Brenner tumor confirmed with pathology and clinical follow-up were retrospectively analyzed, and the masses were described for location, size, configuration, enhancement pattern, presence of calcification and metastatic spread. Results There were 7 tumors in 5 patients, 3 patients had unilateral tumors and 2 had bilateral Brenner tumors (left side 3 and right side 4), with tumor size ranging from 1.52 to 16.25 cm (mean 7.36 cm). Five masses in 4 patients were benign, 2 (bilateral tumors in 1 patient) were malignant. All tumors had well-defined margin. One patient with bilateral benign tumors had large pleural effusion and seroperitoneum. Five tumors in 4 patients (5/7, 71.43%) were solid and had calcification, 2 tumors in 1 patients (2/7, 28.57%) were mainly cystic, with septa in the tumors. The solid part of all tumors were inhomogeneous and had mild enhancement. Conclusion CT findings of ovary Brenner tumor have some characteristics. Combining with clinical manifestations, CT is helpful for the diagnosis of ovary Brenner tumor.
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Objective To evaluate the diagnostic value of multi-slice spiral CT(MSCT)perfusion imaging in chronic obstructive pulmonary disease(COPD).Methods Twenty COPD patients and20 volunteers underwent 8-row detector spiral CT(MSCT)perfusion imaging using cine scan mode with5 mm slice thickness.0.5 s rotation time and a total scan time of 45 s with 5 s intervals.60 ml contrast agent(300 mg I/ml)were administered at a rate of 4 ml/s from the forearm superficial vein.The imaging data were transferred to a workstation.A time-density curve and pseudo-color map were generated automatically with GE CT perfusion 3 software,the blood flow(BF),blood volume(BV),mean transit time(MTr)and permeability surface(PS)were measured.Results Time-density curve was flatter and the peak of the curve was obviously lower in COPD patients than the volunteers.The BF.BV.PS in COPD volunteers was(10.58 ±4.85)s and(4.50 ±1.71)s respectively.The BF,BV and PS in COPD patients Was lower than the volunteers,the MTY was higher(P＜0.01).Conclusion MSCT perfusion imaging is helpful for the diagnosis of COPD.
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Objective To evaluate the role of dynamic contrast-enhanced magnetic resonance imaging (MRI) in the diagnose of prostatic cancer and benign prostatic hyperplasia (BPH), and to determine the correlation between dynamic MRI findings with angiogenesis.Methods Thirty-two cases of prostatic cancer and 40 cases of BPH underwent dynamic contrast-enhanced MRI.All the patients in this study were diagnosed by histopathology.The results of dynamic contrast-enhanced MRI were evaluated by early-phase enhancement parameters and time-signal intensity curves (SI-T curves), and the curves were classified according to their shapes as type Ⅰ, which had steady enhancement; type Ⅱ, plateau of signal intensity; and type Ⅲ, washout of signal intensity.The pathologic specimens of region of interest (ROI) were obtained, and HE staining, immunohistochemical vascular endothelial growth factor (VEGF), and microvessel density (MVD) measurements were performed.The relationships among dynamic contrast-enhanced MRI features, VEGF, and MVD expression were analyzed.Results In the early-phase enhancement parameters of dynamic contrast-enhanced MRI, onset time,maximum signal intensity, and early-phase enhancement rate differed between prostatic cancer and BPH(P
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Objective To investigate the MR imaging findings of colonic carcinoma and the diagnostic value of MRI. Methods Multi-planar and multi-sequence MRI scanning, before and after contrast enhancement, were performed in 40 patients with colonic cancer. The patients were fasted for 12 hours, prepared with clean clysis or senna at night before study, given 10 mg of anisodamine 10 minutes before study, and then infused with 800～1 000 ml physiological saline immediately before study by anus. Dukes staging and resectability evaluation were made in 32 patients before surgery and meanwhile the results were compared with pathology. Results Colonic anatomy and surrounding organs were clearly demonstrated on MRI in 40 patients with colonic cancer, particularly in recta and sigmoid flexure. The tumours showed iso-intensity on T 1WI, iso-intensity or slight high-intensity signal on T 2WI, and high-intensity signal on SPIR. Remarkable enhancement was seen in 35/40 (87.5%). Invasion of surrounding organs occurred in 8/40(20.0%)and MRI revealed 6; Meanwhile, MRI revealed lymph node metastasis in 8 out of 12 cases. 32 patients were regarded as resectable before surgery, and 8 patients as unresectable. Four patients were overestimated, the accuracy of preoperative evaluation for the resectability was 87.5%, and the detecting rate of colonic cancer was 100.0%. Conclusion MRI can clearly show the colonic wall thickness, anatomic structure and surrounding anatomy. For the diagnosis of colonic cancer, MRI can not only demonstrate all its morphologic features, such as mass, thickened wall, and invasion of adjacent organs, but also swollen lymph node and metastasis in abdominal cavity. MRI is very helpful in the diagnosis, staging, and respectability evaluation of colonic cancer.