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Objective To investigate the effect of 100 kVp low tube voltage combined with adaptive statistical iterative reconstruc-tion-Veo(ASIR-V)on the imaging display,image quality and radiation dose of Adamkiewicz artery(AKA).Methods Ninety patients with computed tomography angiography(CTA)of aorta were randomly divided into two groups.In group A,the tube voltage was 100 kVp,and ASIR-V was 80%reconstructed.The tube voltage in group B was 120 kVp,and adaptive statistical iterative recon-struction(ASIR)was 40%reconstructed.The CT value and the standard deviation(SD)value of descending aorta were measured at the 12th thoracic vertebra level,and the CT value and the SD value of the spinal cord were measured at the same level to calculate the signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)of AKA.According to the continuity between AKA and intercostal artery or lumbar artery,the visualization of AKA was evaluated by two doctors with a double-blinded method and a five-point method,and the radiation doses of group A and group B were compared.Results Compared with group B,the CT value of aorta in group A was sig-nificantly increased by about 22.83%(P<0.001).The background noise of AKA in group A was significantly lower than that in group B(P<0.001),and the SNR and CNR were significantly higher than those in group B(P<0.001).The visualization score of AKA in group A was higher than that in group B(P<0.05).The effective dose(ED)in group A was significantly lower than that in group B by about 41.28%(P<0.001).Conclusion 100 kVp combined with ASIR-V technique for spinal cord AKA imaging can obtain better image quality,improve the sensitivity of AKA display and reduce the radiation dose.
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Objective Exploration of the application value of the third-generation dual source CT low tube voltage (70 kVp) scanning combined with advanced modeling iterative reconstruction (ADMIRE) technique in children with adenoid examination. Methods CT scans were performed in patients with clinically suspected adenoid hypertrophy. They were divided into two groups according to the time of treatment. Group A (40 cases) : low tube voltage (70 kVp) scan, reference tube current 163 mAs, reconstruction with ADMIER, Intensity 3; Group B (40 cases) : conventional 100 kVp, reference tube current 163 mAs, conventional (filtered back-projection, FBP) reconstruction;rest of the scanning parameters remained unchanged. The subjective scores and objective quality indicators of the images (CT value, image noise, signal noise ratio (SNR) , contrast noise ratio (CNR)) and radiation dose of the two groups were compared. Results The difference of radiation dose between group A and group B was statistically significant (P < 0.05). The radiation dose of group A was lower than that of group B by 77.58％.Compared with group B, the image noise of group A increased by 0.002％; the SNR decreased by 0.01％; CNR increased by 0.03％; there was no significant difference in objective quality evaluation index and subjective score between two groups in the image quality (P> 0.05). Conclusion The third-generation dual-source CT low-tube voltage (70 kVp) combined with ADMIRE reconstruction technique for children with adenoid scan can effectively reduce the radiation dose while ensuring image quality.
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Objective To investigate the feasibility, image quality, and safety of low?tube?voltage, low iodine load iso?osmolar contrast comprehensive cardiac and aortoiliac CT angiography (CTA) for transcatheter aortic valve replacement (TAVR) planning. Methods Ninety?eight consecutive TAVR candidates prospectively underwent combined contrast?enhanced CTA of the aortic root complex and vascular access route. Patients were assigned to group A (2nd generation dual?source CT, 100 kV, contrast 270 mgI/ml iodixanol) or group B (2nd generation dual?source CT, 120 kV, contrast 370 mgI/ml). Mean vascular attenuation, noise, signal?to?noise ratio (SNR), and contrast?to?noise ratio (CNR) of aorta including aortic root, aortic arch, descending aorta at level of diaphragm, abdominal aorta at level of renal artery and femoral artery were compared. Patient creatinine levels before the examination of CTA and during follow?up (24—48 h) were measured. Results The image quality score of aortic root and whole aorta was (4.2±0.7) and (4.3±0.4) respectively in experimental group, (4.3±0.6) and (4.3±0.3) in control group. No significant difference in subjective image quality score between two groups including aortic root image and whole aorta image (t=-0.130,-0.155,P=0.694, 0.822). The image noise of aortic root and femoral artery were higher in experimental group than that in control group (P<0.05). Radiation dose in experimental group was higher than that in control group [(6.1 ± 0.4) vs. (8.0 ± 0.4) mSv, t=-9.253, P=0.001]. There were no significant changes in creatinine levels among groups during the follow?up. Conclusion TAVR candidates can be safely and effectively evaluated by a comprehensive CTA protocol with low iodine load iso?osmolar contrast using low?tube?voltage acquisition.
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Objective To evaluate the clinical value of low kVp with iterative reconstruction in multislice spiral computed tomography of lumber vertebrae in young soldiers. Methods Sixty young soldiers who suffered from lumbar diseases were randomly divided into a control group(120 kVp)and a test group(100 kVp),who underwent CT examination with 120 kVp tube voltage in the control group and 100 kVp tube voltage in the test group.The control group went through filtered back projection (FBP)for image reconstruction.The test group applied FBP or sinogram-affirmed iterative reconstruction(SAFIRE)based on image reconstruction requirements,and then were divided into FBP test group and SAFIRE test group.The noise and SNR (signal to noise ratio)of the images were measured in each group.Meanwhile two experienced radiologists evaluated the quality of images.CTDIvol,DLP and ED were used to measure the scan dose in each group.Mean tube current was recorded by CARE Dose 4D.The data were analyzed with SPSS.Results There were no significant difference between the objective and subjective image evaluations in SAFIRE test group and the control group (P>0.05),while there were statistical differences between FBP test group and the control group or between the two test groups(P<0.05).The radiation doses in the test groups were both lower significantly than that in the control group,and the ED values in the test groups were decreased by 43% when compared with the control group. The test groups had the tube voltages not obviously different from that in the control group (P>0.05). Conclusion The radiation dose in the lumbar multislice spiral CT examination of young soldiers is decreased significantly when the tube voltage falls to 100 kVp,the same image quality as that by conventional 120 kVp tube voltage can be obtained by combining iterative reconstruction.
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OBJECTIVE: To evaluate the feasibility and image quality (IQ) of prospectively high-pitch coronary CT angiography (CCTA) with low contrast medium injection rate at 70 kVp. MATERIALS AND METHODS: One hundred and four patients with suspected coronary artery disease (body mass index < 26 kg/m², sinus rhythm and heart rate < 70 beats/min) were prospectively enrolled and randomly divided into two groups. In group A and group B, 28 mL and 40 mL of 370 mgI/mL iodinated contrast media was administrated at a flow rate of 3.5 and 5 mL/s, respectively. CT values, noise, signal-to-noise ratio, contrast-to-noise ratio (CNR) of the proximal segments of coronary arteries and subjective IQ were evaluated. RESULTS: The CT values and noise in group A were significantly lower than those in group B (434–485 Hounsfield units [HU] vs. 772–851 HU, all p < 0.001; 17.8–22.3 vs. 23.3–26.4, all p < 0.005). The CNRs of the right coronary artery and left main artery showed no statistical difference between the two groups (42.1 ± 13.8 vs. 36.8 ± 16.0, p = 0.074; 38.7 ± 10.6 vs. 38.1 ± 17.0, p = 0.819). No statistical difference was observed between the two groups in IQ scores (3.04 ± 0.75 vs. 3.0 ± 0.79, p = 0.526) and diagnostic ratio (96.1% [50/52] vs. 94.2% [49/52], p = 0.647). CONCLUSION: Prospective high-pitch CCTA at 70 kVp with 28 mL of contrast media and injection rate of 3.5 mL/s could provide diagnostic IQ for normal-weight patients with heart rate of < 70 beats/min.
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Humans , Angiography , Arteries , Contrast Media , Coronary Artery Disease , Coronary Vessels , Heart Rate , Noise , Prospective Studies , Signal-To-Noise RatioABSTRACT
OBJECTIVE: To evaluate the feasibility and image quality (IQ) of prospectively high-pitch coronary CT angiography (CCTA) with low contrast medium injection rate at 70 kVp. MATERIALS AND METHODS: One hundred and four patients with suspected coronary artery disease (body mass index < 26 kg/m², sinus rhythm and heart rate < 70 beats/min) were prospectively enrolled and randomly divided into two groups. In group A and group B, 28 mL and 40 mL of 370 mgI/mL iodinated contrast media was administrated at a flow rate of 3.5 and 5 mL/s, respectively. CT values, noise, signal-to-noise ratio, contrast-to-noise ratio (CNR) of the proximal segments of coronary arteries and subjective IQ were evaluated. RESULTS: The CT values and noise in group A were significantly lower than those in group B (434–485 Hounsfield units [HU] vs. 772–851 HU, all p < 0.001; 17.8–22.3 vs. 23.3–26.4, all p < 0.005). The CNRs of the right coronary artery and left main artery showed no statistical difference between the two groups (42.1 ± 13.8 vs. 36.8 ± 16.0, p = 0.074; 38.7 ± 10.6 vs. 38.1 ± 17.0, p = 0.819). No statistical difference was observed between the two groups in IQ scores (3.04 ± 0.75 vs. 3.0 ± 0.79, p = 0.526) and diagnostic ratio (96.1% [50/52] vs. 94.2% [49/52], p = 0.647). CONCLUSION: Prospective high-pitch CCTA at 70 kVp with 28 mL of contrast media and injection rate of 3.5 mL/s could provide diagnostic IQ for normal-weight patients with heart rate of < 70 beats/min.
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Humans , Angiography , Arteries , Contrast Media , Coronary Artery Disease , Coronary Vessels , Heart Rate , Noise , Prospective Studies , Signal-To-Noise RatioABSTRACT
Objective To explore the feasibility of low-tube-voltage and low-concentration contrast agent applied to coronary computed tomography angiography (CTA) in the overweight patients. Methods Totally 83 overweight patients with suspected coronary heart disease who underwent coronary artery angiography were randomly assigned into two groups. Group A used 100 kVp and ioversol-320 mg/ml, and Group B received 120 kVp and iopamidol-370 mg/ml. Both the groups went through prospectively ECG-gated scanning. The two groups were compared on the image quality, radiation dose, iodine intake and coronary artery segments scores. Results The effective radiation dose and iodine intake in Group A were significantly lower than those in Group B (P<0.05). Group A had the coronary artery CT value and image noise lower significantly than Group B (P<0.05). No significant differences in signal to noise ratio, contrast to noise ratio and coronary artery segments scores were observed between the two groups (P>0.05). Conclusion For coronary artery CTA in the overweight patients, low-tube-voltage and low-concentration contrast agent still preserves the image quality, as well as significantly reduces the radiation dose and iodine intake.
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Objective:To investigate the effect and application feasibility of low tube voltage, low concentration of contrast agent volume to CTA in the diagnosis of coronary artery stenosis and its effect.Methods: Seventy two cases of suspected patients with coronary atherosclerosis selected as the object Using random number table method, all patients were divided into group A and group B 36 cases in each group, two groups of patients underwent 320 slice CTA examination, in group A the tube voltage is 120kV, the contrast agent was 350mgI/mL iodixanol group, B tube voltage is set to 100kV, the contrast agent was 270mgI/mL iodixanol. According to the examination results of group A, group B and catheter coronary angiography (CCA), evaluated group A, group B of acquiring the image quality and radiation dose of patients, and analyzed the sensitivity of A, B and CCA examination of the extent of coronary artery stenosis degree and deliberately.Results: The quartering method showed no significant difference between the group A and the group B of image quality. There was significant difference between the two groups of patients with the image noise and enhance the effect (t=-4.736, 11.927;P<0.05); Group B of coronary artery stenoses (more than 50%) and severe stenosis (more than 75%) sensitivity, specially degree and coincidence rate compared with the results of CCA showed no significant difference. Kappa consistency analysis showed that the two consistency is good(kappa=1.320,P<0.001).Conclusion: In the premise of ensuring the image quality with low tube voltage, low concentration of contrast agent volume coronary CTA examination had safety and reliability of inspection.
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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).Conclusion Using ATCM low-kV with high NI scanning can reduce radiation dose without interference on image quality for peripheral artery CTA.
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OBJECTIVE: To investigate the validity of the 100 kVp setting in CT venography (CTV) in the diagnosis of deep vein thrombosis (DVT), and to evaluate the feasibility of reducing the amount of administered iodine in this setting. MATERIALS AND METHODS: After receiving the contrast medium (CM) of 2.0 mL/kg, 88 patients underwent CTV of the pelvis and lower extremities by using one of four protocols: Group A, 120 kVp setting and 370 mgI/mL CM; group B, 120 kVp and 300 mgI/mL; group C, 100 kVp and 370 mgI/mL; group D, 100 kVp and 300 mgI/mL. The groups were evaluated for venous attenuation, vein-to-muscle contrast-to-noise ratio (CNRVEIN), DVT-to-vein contrast-to-noise ratio (CNRDVT), and subjective degree of venous enhancement and image quality. RESULTS: Venous attenuation and CNRVEIN were significantly higher in group C (144.3 Hounsfield unit [HU] and 11.9), but there was no significant difference between group A (118.0 HU and 8.2) and D (122.4 HU and 7.9). The attenuation value of DVT was not significantly different among the four groups, and group C had a higher absolute CNRDVT than the other groups. The overall diagnostic image quality and venous enhancement were significantly higher in group C, but there was no difference between groups A and D. CONCLUSION: The 100 kVp setting in CTV substantially help improve venous enhancement and CNRVEIN. Furthermore, it enables to reduce the amount of administered iodine while maintaining venous attenuation, as compared with the 120 kVp setting.
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Female , Humans , Male , Middle Aged , Contrast Media/administration & dosage , Feasibility Studies , Iohexol/administration & dosage , Linear Models , Lower Extremity/blood supply , Phantoms, Imaging , Phlebography/methods , Statistics, Nonparametric , Tomography, X-Ray Computed/methods , Venous Thrombosis/diagnostic imagingABSTRACT
OBJECTIVE: To investigate whether the low-tube-voltage (80-kVp), intermediate-tube-current (340-mAs) MDCT using the Iterative Reconstruction in Image Space (IRIS) algorithm improves lesion-to-liver contrast at reduced radiation dosage while maintaining acceptable image noise in the detection of hepatocellular carcinomas (HCC) in thin (mean body mass index, 24 +/- 0.4 kg/m2) adults. SUBJECTS AND METHODS: A phantom simulating the liver with HCC was scanned at 50-400 mAs for 80, 100, 120 and 140-kVp. In addition, fifty patients with HCC who underwent multiphasic liver CT using dual-energy (80-kVp and 140-kVp) arterial scans were enrolled. Virtual 120-kVP scans (protocol A) and 80-kVp scans (protocol B) of the late arterial phase were reconstructed with filtered back-projection (FBP), while corresponding 80-kVp scans were reconstructed with IRIS (protocol C). Contrast-to-noise ratio (CNR) of HCCs and abdominal organs were assessed quantitatively, whereas lesion conspicuity, image noise, and overall image quality were assessed qualitatively. RESULTS: IRIS effectively reduced image noise, and yielded 29% higher CNR than the FBP at equivalent tube voltage and current in the phantom study. In the quantitative patient study, protocol C helped improve CNR by 51% and 172% than protocols A and B (p < 0.001), respectively, at equivalent radiation dosage. In the qualitative study, protocol C acquired the highest score for lesion conspicuity albeit with an inferior score to protocol A for overall image quality (p < 0.001). Mean effective dose was 2.63-mSv with protocol A and 1.12-mSv with protocols B and C. CONCLUSION: CT using the low-tube-voltage, intermediate-tube-current and IRIS help improve lesion-to-liver CNR of HCC in thin adults during the arterial phase at a lower radiation dose when compared with the standard technique using 120-kVp and FBP.