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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 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 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 clinical value of CT-guided interstitial implantation of ~(125)I seeds for the treatment of pulmonary carcinoma. Methods A total of 18 patients with pulmonary carcinoma underwent CT-guided interstitial implantation of ~(125)I seeds. According to the size of tumor,effective dose, and optimal quantity of ~(125)I seeds to the patient that were computed by a developed algorithm in Treatment Planning System (TPS), the ~(125)I seeds were implanted into the tumor tissues under the guidance of spiral CT. The patients were reexamined by CT 2 months after the operation and were followed up for 6 months. Results A total of 812 seeds were implanted into the 18 lesions in the 18 cases (45.1 seeds per case in average). The CT scan performed 2 months after the operation showed CR in 7 cases, PR in 10, and NC in 1. The total effectiveness (CR+PR) rate was 94% (17/18). Conclusions CT-guided interstitial implantation of ~(125)I seeds is a effective, minimally invasive, and low toxic method for valid and minimally traumatic treatment for middle- and late-stage lung cancer. Further application and long-term observation are necessary.