Objective: To compare and analyze the image quality and radiation dose of three scanning modes of dual-source CT coronary artery retrospectively, and to discuss the application value of TurboFlash coarse pitch scannin...Objective: To compare and analyze the image quality and radiation dose of three scanning modes of dual-source CT coronary artery retrospectively, and to discuss the application value of TurboFlash coarse pitch scanning mode. Methods: The imaging data of 100 patients who underwent CT coronary angiography (CCTA) using Siemens force CT retrospective gated triggering spiral scan (RES-SPIRAL), adaptive prospective gated triggering sequence scan (SEQ) and prospective coarse pitch scan (TurboFlash) retrospectively was collected. The image quality was evaluated by objective and subjective methods. The effective radiation dose of patients was compared and analyzed, and the indications of the three scanning modes were analyzed. The application value of dual-source CT TurboFlash coarse pitch scanning in coronary artery imaging was evaluated. Results: The results showed that the left main coronary artery, the right coronary artery and their tertiary branches could be clearly displayed in the three groups of images: the left anterior descending branch, the left circumflex branch, and their three-level branches. There was no statistical difference in subjective image quality among the three groups of pictures (P > 0.05). There was no statistical difference in objective evaluation indexes, such as CT value, SNR, CNR and Noise among the three groups (P > 0.05). The patient radiation dose results showed that the effective radiation dose ED of RES-SPIRA scan was (9.22 ± 1.33) mSv. The dose of SEQ was (2.88 ± 2.47) mSv, and the dose of TurboFlash was (0.51 ± 0.16) mSv. There was significant difference in comparison of the three groups (P 0.05). RES-spiral scanning had the highest radiation dose and TurboFlash coarse pitch scanning (TurboFlash) had the lowest radiation dose. Conclusion: TurboFlash coarse pitch scanning is low in dosage, fast in speed and wide in adaptability. It is especially suitable for the elderly, children, coma and other patients who cannot cooperate with breath-holding examination, as well as for the screening and examination of coronary artery diseases in asymptomatic population. Undoubtedly, it is a worthy method of heart coronary artery examination.展开更多
Flash Joule heating(FJH),as a high-efficiency and low-energy consumption technology for advanced materials synthesis,has shown significant potential in the synthesis of graphene and other functional carbon materials.B...Flash Joule heating(FJH),as a high-efficiency and low-energy consumption technology for advanced materials synthesis,has shown significant potential in the synthesis of graphene and other functional carbon materials.Based on the Joule effect,the solid carbon sources can be rapidly heated to ultra-high temperatures(>3000 K)through instantaneous high-energy current pulses during FJH,thus driving the rapid rearrangement and graphitization of carbon atoms.This technology demonstrates numerous advantages,such as solvent-and catalyst-free features,high energy conversion efficiency,and a short process cycle.In this review,we have systematically summarized the technology principle and equipment design for FJH,as well as its raw materials selection and pretreatment strategies.The research progress in the FJH synthesis of flash graphene,carbon nanotubes,graphene fibers,and anode hard carbon,as well as its by-products,is also presented.FJH can precisely optimize the microstructures of carbon materials(e.g.,interlayer spacing of turbostratic graphene,defect concentration,and heteroatom doping)by regulating its operation parameters like flash voltage and flash time,thereby enhancing their performances in various applications,such as composite reinforcement,metal-ion battery electrodes,supercapacitors,and electrocatalysts.However,this technology is still challenged by low process yield,macroscopic material uniformity,and green power supply system construction.More research efforts are also required to promote the transition of FJH from laboratory to industrial-scale applications,thus providing innovative solutions for advanced carbon materials manufacturing and waste management toward carbon neutrality.展开更多
Flash droughts(FDs)develop quickly and can rapidly deplete soil moisture,posing significant threats to agriculture and pastoral systems.To investigate the spatiotemporal characteristics and development mechanisms of F...Flash droughts(FDs)develop quickly and can rapidly deplete soil moisture,posing significant threats to agriculture and pastoral systems.To investigate the spatiotemporal characteristics and development mechanisms of FDs in Inner Mongolia,China,and to assess the roles of key meteorological drivers in driving soil moisture variability,FD events were identified using root-zone soil moisture data during the growing seasons from 1982 to 2022.The results indicate the presence of five FD hotspot regions,located in the southern Alxa Plateau,the Hetao Plain in Bayannur,the northwestern Xilingol Plain,the western Liaohe River Plain,and the northern Da Hinggan Ling.Over 41 years,FDs occurred on average 7.44 events across the study area,with a mean duration of 9.17 pentads(1 pentad equals 5 days).The duration exhibited a significant increasing trend of 0.39 pentads/10 years.FD onsets primarily lasted for 2-3 pentads.During the FD development phase,precipitation and evapotranspiration decreased while temperature,potential evapotranspiration,incoming solar radiation,and vapor pressure deficit increased.The dominant meteorological drivers of FD development exhibited notable spatial heterogeneity across hotspot regions,and vapor pressure deficit consistently was the most influential factor.These findings improve the understanding of climate drivers at different stages of FD development and provide scientific support for early warning and prevention of droughts in Inner Mongolia.展开更多
Waterborne acrylic coatings are widely utilized due to their cost-effectiveness,high transparency,strong resistance to weather and chemicals,impressive mechanical properties,and excellent adhesion to various substrate...Waterborne acrylic coatings are widely utilized due to their cost-effectiveness,high transparency,strong resistance to weather and chemicals,impressive mechanical properties,and excellent adhesion to various substrates.In these coatings,a reactive emulsifier containing phosphate groups can be integrated into the molecular chain during polymerization,which enhances the coating's compactness and corrosion resistance.This work focuses on the synthesis of styrene-butyl acrylate(St-BA)latex and methyl methacrylate-butyl acrylate(MMA-BA)latex using the reactive phosphate emulsifier ANPEO_(10)-P_(1) through seed emulsion polymerization,achieving a conversion rate of approximately 99%and a solid content close to 50%.The resulting coatings from St-BA and MMA-BA latexes demonstrated long-term corrosion protection for carbon steel and aluminum alloy due to in-situ phosphatization,effectively preventing flash rust.Notably,the MMA-BA coating exhibited remarkable durability,enduring immersion for up to 1224 h(51 d)on Q 235 carbon steel before reaching the failure threshold(|Z|0.01 Hz£106Ω·cm^(2))on Q 235 carbon steel.On 5052 aluminum alloy,the St-BA coating maintained|Z|0.01 Hz>10^(8)Ω·cm^(2) for 480 h(20 d).Furthermore,the corrosion resistance of St-BA and MMA BA coatings on Q 235 steel sheet and 5052 aluminum alloy surpassed that of commercially available MMA-BA and St BA coatings after immersion in a 3.5 wt%NaCl aqueous solution.This work also delves into the anticorrosion mechanism of MMA-BA and St-BA coatings.展开更多
Objective To investigate the image quality, radiation dose and diagnostic value of the low-tube-voltage high-pitch dual-source computed tomography(DSCT) with sinogram affirmed iterative reconstruction(SAFIRE) for non-...Objective To investigate the image quality, radiation dose and diagnostic value of the low-tube-voltage high-pitch dual-source computed tomography(DSCT) with sinogram affirmed iterative reconstruction(SAFIRE) for non-enhanced abdominal and pelvic scans. Methods This institutional review board-approved prospective study included 64 patients who gave written informed consent for additional abdominal and pelvic scan with DSCT in the period from November to December 2012. The patients underwent standard non-enhanced CT scans(protocol 1) [tube voltage of 120 k Vp/pitch of 0.9/filtered back-projection(FBP) reconstruction] followed by high-pitch non-enhanced CT scans(protocol 2)(100 k Vp/3.0/SAFIRE). The total scan time, mean CT number, signal-to-noise ratio(SNR), image quality, lesion detectability and radiation dose were compared between the two protocols. Results The total scan time of protocol 2 was significantly shorter than that of protocol 1(1.4±0.1 seconds vs. 7.6±0.6 seconds, P<0.001). There was no significant difference between protocol 1 and protocol 2 in mean CT number of all organs(liver, 55.4±6.3 HU vs. 56.1±6.8 HU, P=0.214; pancreas, 43.6±5.9 HU vs. 43.7±5.8 HU, P=0.785; spleen, 47.9±3.9 HU vs. 49.4±4.3 HU, P=0.128; kidney, 32.2±2.3 HU vs. 33.1±2.3 HU, P=0.367; abdominal aorta, 44.8±5.6 HU vs. 45.0±5.5 HU, P=0.499; psoas muscle, 50.7±4.1 HU vs. 50.3±4.5 HU, P=0.279). SNR on images of protocol 2 was higher than that of protocol 1(liver, 5.0±1.2 vs. 4.5±1.1, P<0.001; pancreas, 4.0±1.0 vs. 3.6±0.8, P<0.001; spleen, 4.7±1.0 vs. 4.1±0.9, P<0.001; kidney, 3.1±0.6 vs. 2.8±0.6, P<0.001; abdominal aorta, 4.1±1.0 vs. 3.8±1.0, P<0.001; psoas muscle, 4.5±1.1 vs. 4.3±1.2, P=0.012). The overall image noise of protocol 2 was lower than that of protocol1(9.8±3.1 HU vs. 11.1±3.0 HU, P<0.001). Image quality of protocol 2 was good but lower than that of protocol 1(4.1±0.7 vs. 4.6±0.5, P<0.001). Protocol 2 perceived 229 of 234 lesions(97.9%) that were detected in protocol 1 in the abdomen and pelvis. Radiation dose of protocol 2 was lower than that of protocol 1(4.4±0.4 m Sv vs. 7.3±2.4 m Sv, P<0.001) and the mean dose reduction was 41.4%. Conclusion The high-pitch DSCT with SAFIRE can shorten scan time and reduce radiation dose while preserving image quality in non-enhanced abdominal and pelvic scans.展开更多
Objective To prospectively investigate the diagnostic accuracy for coronary artery stenosis of prospectively electrocardiogram-triggered spiral acquisition mode (high pitch mode) dual-source computed tomography corona...Objective To prospectively investigate the diagnostic accuracy for coronary artery stenosis of prospectively electrocardiogram-triggered spiral acquisition mode (high pitch mode) dual-source computed tomography coronary angiography (CTCA) in patients with relatively higher heart rates (HR) compared with catheter coronary angiography (CCA). Methods Forty-seven consecutive patients with relatively higher HR (>65 and <100 bpm) (20 male, 27 female; age 55±10 years) who both underwent dual-source CTCA and CCA were prospectively included in this study. All patients were performed CTCA using high pitch mode setting at 20%-30% of the R-R interval for the image acquisition. All coronary segments were evaluated by two blinded and independent observers with regard to image quality on a three-point scale (1: excellent to 3: non-diagnostic) and for the presence of significant coronary stenoses (defined as diameter narrowing exceeding 50%). Considered CCA as the standard of reference, the sensitivity, specificity, positive predictive value and negative predictive value were calculated. Radiation dose values were calculated using the dose-length product. Results Image quality was rated as being score 1 in 92.4% of segments, score 2 in 6.1% of segmentsand score 3 in 1.5% of segments. The average image quality score per segment was 1.064±0.306. The HR variability of patients with image score 1, 2 and 3 were 2.29±1.06 bpm, 5.17±1.37 bpm, 8.88±1.53 bpm, respectively. The average HR variability of patients with different image scores were significantly different (F=170.402, P=0.001). The sensitivity, specificity, positive and negative predictive values were 92.6%, 97.0%, 87.6%, 98.3%, respectively, per segment and 90.0%, 95.2%, 85.3%, 96.9%, respectively, per vessel and 100%, 63.6%, 90.0%, 100%, respectively, per patient. The effective radiation dose was on average 0.86±0.16 mSv. Conclusion In patients with HR more than 65 bpm and below 100 bpm without cardiac arrhythmia, the prospectively electrocardiogram-gated high-pitch spiral acquisition mode with image acquired timing set at 20%-30% of the R-R interval provides a high diagnostic accuracy for the assessment of coronary stenoses combined with a 1.5% of non-diagnostic coronary segments and a radiation dose below 1 mSv.展开更多
Objective To investigate the feasibility of acquiring the similar homogeneous enhancement using bolus-tracking techniques with shortened respiratory time in prospectively electrocardiogram-gated high-pitch spiral acqu...Objective To investigate the feasibility of acquiring the similar homogeneous enhancement using bolus-tracking techniques with shortened respiratory time in prospectively electrocardiogram-gated high-pitch spiral acquisition mode (Flash mode) coronary computed tomography angiography (CCTA) compared with test bolus technique. Methods One hundred and eighty-four consecutive patients with mean heart rate ≤65 beats per minute undergoing CCTA were prospectively included in this study. The patients were randomly divided into two groups. Patients in the group A (n=92) instructed to shorten respiratory time received CCTA using bolus-tracking technique with high-pitch spiral acquisition mode (Flash mode), while those in the group B (n=92) underwent CCTA with test bolus technique. The attenuation in the ascending aorta, image noise, contrast-to-noise ratio and radiation doses of the two groups were assessed. Results There were no significant differences in the mean attenuation values in the ascending aorta (483.18±59.07 HU vs. 498.7±83.51 HU, P=0.183), image noise (21.4±4.5 HU vs. 20.9±4.3 HU, P=0.414), contrast-to-noise ratio (12.1±4.2 vs. 13.8±5.1, P=0.31) between the groups A and B. There were no significant differences in the radiation dose of dynamic monitoring scans (0.056±0.026 mSv vs. 0.062±0.018 mSv, P=0.068) and radiation dose of angiography (0.94±0.07 mSv vs. 0.96±0.15 mSv,P=0.926) between the two groups, while 15 mL less contrast material volume was administered in the group A than the group B. Conclusion Bolus-tracking technique with shortened time of respiratory in Flash mode of dual-source CT yields the similar homogeneous enhancement with less contrast material in comparison to the test bolus technique.展开更多
Truncus arteriosus is an uncommon congenital cardiac abnormality which is characterized by a single arterial trunk origin from the heart that supplies both the systemic,pulmonary and coronary circulation.We present a ...Truncus arteriosus is an uncommon congenital cardiac abnormality which is characterized by a single arterial trunk origin from the heart that supplies both the systemic,pulmonary and coronary circulation.We present a preterm newborn female patient with type 2 truncusarteriosus,left superior vena cava and aberrant subclavian artery diagnosed with low dose dual-source cardiac computed tomography(CT).We discuss that low dose dual-source cardiac CT has more advantages than other imaging methods and it is an important modality for assessment of patients with conotruncal anomalies such as truncusarteriosus.展开更多
Background:Pulmonary atresia(PA)is a group of heterogeneous complex congenital heart disease.Only one study modality might not get a correct diagnosis.This study aims to investigate the diagnostic power of dualsource ...Background:Pulmonary atresia(PA)is a group of heterogeneous complex congenital heart disease.Only one study modality might not get a correct diagnosis.This study aims to investigate the diagnostic power of dualsource computed tomography(DSCT)for all intracardiac and extracardiac deformities in patients with PA compared with transthoracic echocardiography(TTE).Materials and Methods:This retrospective study enrolled 79 patients and divided them into three groups according to their main diagnosis.All associated malformations and clinical information,including treatments,were recorded and compared among the three groups.The diagnostic power of DSCT and TTE on all associated malformations were compared.The surgical index(McGoon ratio,pulmonary arterials index(PAI),and total neopulmonary arterial index)and radiation dose were calculated on the basis of DSCT.Results:Of the patients,32,30,and 17 were divided into the groups of PA with ventricular septal defect(VSD),PA with VSD and major aortopulmonary collateral arteries,and PA with other major malformations,respectively.Consequently,182,162,and 13 intracardiac,extracardiac,and other major malformations were diagnosed,respectively.Moreover,DSCT showed a better diagnostic performance in extracardiac deformities(154 vs.117,p<0.001),whereas TTE could diagnose intracardiac deformities better(159 vs.139,p=0.001).The McGoon ratio,PAI,and treatment methods were significantly different among the three groups(p=0.014,p=0.008,and p=0.018,respectively).Conclusion:More than one imaging modality should be used to make a correct diagnosis when clinically suspecting PA.DSCT is superior to TTE in diagnosing extracardiac deformities and could be used to roughly calculate surgical indices to optimize treatment strategy.展开更多
文摘Objective: To compare and analyze the image quality and radiation dose of three scanning modes of dual-source CT coronary artery retrospectively, and to discuss the application value of TurboFlash coarse pitch scanning mode. Methods: The imaging data of 100 patients who underwent CT coronary angiography (CCTA) using Siemens force CT retrospective gated triggering spiral scan (RES-SPIRAL), adaptive prospective gated triggering sequence scan (SEQ) and prospective coarse pitch scan (TurboFlash) retrospectively was collected. The image quality was evaluated by objective and subjective methods. The effective radiation dose of patients was compared and analyzed, and the indications of the three scanning modes were analyzed. The application value of dual-source CT TurboFlash coarse pitch scanning in coronary artery imaging was evaluated. Results: The results showed that the left main coronary artery, the right coronary artery and their tertiary branches could be clearly displayed in the three groups of images: the left anterior descending branch, the left circumflex branch, and their three-level branches. There was no statistical difference in subjective image quality among the three groups of pictures (P > 0.05). There was no statistical difference in objective evaluation indexes, such as CT value, SNR, CNR and Noise among the three groups (P > 0.05). The patient radiation dose results showed that the effective radiation dose ED of RES-SPIRA scan was (9.22 ± 1.33) mSv. The dose of SEQ was (2.88 ± 2.47) mSv, and the dose of TurboFlash was (0.51 ± 0.16) mSv. There was significant difference in comparison of the three groups (P 0.05). RES-spiral scanning had the highest radiation dose and TurboFlash coarse pitch scanning (TurboFlash) had the lowest radiation dose. Conclusion: TurboFlash coarse pitch scanning is low in dosage, fast in speed and wide in adaptability. It is especially suitable for the elderly, children, coma and other patients who cannot cooperate with breath-holding examination, as well as for the screening and examination of coronary artery diseases in asymptomatic population. Undoubtedly, it is a worthy method of heart coronary artery examination.
基金supported by the National Natural Science Foundation of China(52276196)the Foundation of State Key Laboratory of Coal Combustion(FSKLCCA2508)the High-level Talent Foundation of Anhui Agricultural University(rc412307).
文摘Flash Joule heating(FJH),as a high-efficiency and low-energy consumption technology for advanced materials synthesis,has shown significant potential in the synthesis of graphene and other functional carbon materials.Based on the Joule effect,the solid carbon sources can be rapidly heated to ultra-high temperatures(>3000 K)through instantaneous high-energy current pulses during FJH,thus driving the rapid rearrangement and graphitization of carbon atoms.This technology demonstrates numerous advantages,such as solvent-and catalyst-free features,high energy conversion efficiency,and a short process cycle.In this review,we have systematically summarized the technology principle and equipment design for FJH,as well as its raw materials selection and pretreatment strategies.The research progress in the FJH synthesis of flash graphene,carbon nanotubes,graphene fibers,and anode hard carbon,as well as its by-products,is also presented.FJH can precisely optimize the microstructures of carbon materials(e.g.,interlayer spacing of turbostratic graphene,defect concentration,and heteroatom doping)by regulating its operation parameters like flash voltage and flash time,thereby enhancing their performances in various applications,such as composite reinforcement,metal-ion battery electrodes,supercapacitors,and electrocatalysts.However,this technology is still challenged by low process yield,macroscopic material uniformity,and green power supply system construction.More research efforts are also required to promote the transition of FJH from laboratory to industrial-scale applications,thus providing innovative solutions for advanced carbon materials manufacturing and waste management toward carbon neutrality.
基金funded by the Inner Mongolia Autonomous Region Natural Science Foundation Youth Fund Project(Grants No.2024QN04020)A Science and technology program of Inner Mongolia Autonomous Region(Grants No.2022YFDZ0027)。
文摘Flash droughts(FDs)develop quickly and can rapidly deplete soil moisture,posing significant threats to agriculture and pastoral systems.To investigate the spatiotemporal characteristics and development mechanisms of FDs in Inner Mongolia,China,and to assess the roles of key meteorological drivers in driving soil moisture variability,FD events were identified using root-zone soil moisture data during the growing seasons from 1982 to 2022.The results indicate the presence of five FD hotspot regions,located in the southern Alxa Plateau,the Hetao Plain in Bayannur,the northwestern Xilingol Plain,the western Liaohe River Plain,and the northern Da Hinggan Ling.Over 41 years,FDs occurred on average 7.44 events across the study area,with a mean duration of 9.17 pentads(1 pentad equals 5 days).The duration exhibited a significant increasing trend of 0.39 pentads/10 years.FD onsets primarily lasted for 2-3 pentads.During the FD development phase,precipitation and evapotranspiration decreased while temperature,potential evapotranspiration,incoming solar radiation,and vapor pressure deficit increased.The dominant meteorological drivers of FD development exhibited notable spatial heterogeneity across hotspot regions,and vapor pressure deficit consistently was the most influential factor.These findings improve the understanding of climate drivers at different stages of FD development and provide scientific support for early warning and prevention of droughts in Inner Mongolia.
基金Project(52373065)supported by the National Natural Science Foundation of ChinaProject(2220004002898)supported by the Zhuhai Industry University Research Cooperation and Basic and Applied Research Projects,China。
文摘Waterborne acrylic coatings are widely utilized due to their cost-effectiveness,high transparency,strong resistance to weather and chemicals,impressive mechanical properties,and excellent adhesion to various substrates.In these coatings,a reactive emulsifier containing phosphate groups can be integrated into the molecular chain during polymerization,which enhances the coating's compactness and corrosion resistance.This work focuses on the synthesis of styrene-butyl acrylate(St-BA)latex and methyl methacrylate-butyl acrylate(MMA-BA)latex using the reactive phosphate emulsifier ANPEO_(10)-P_(1) through seed emulsion polymerization,achieving a conversion rate of approximately 99%and a solid content close to 50%.The resulting coatings from St-BA and MMA-BA latexes demonstrated long-term corrosion protection for carbon steel and aluminum alloy due to in-situ phosphatization,effectively preventing flash rust.Notably,the MMA-BA coating exhibited remarkable durability,enduring immersion for up to 1224 h(51 d)on Q 235 carbon steel before reaching the failure threshold(|Z|0.01 Hz£106Ω·cm^(2))on Q 235 carbon steel.On 5052 aluminum alloy,the St-BA coating maintained|Z|0.01 Hz>10^(8)Ω·cm^(2) for 480 h(20 d).Furthermore,the corrosion resistance of St-BA and MMA BA coatings on Q 235 steel sheet and 5052 aluminum alloy surpassed that of commercially available MMA-BA and St BA coatings after immersion in a 3.5 wt%NaCl aqueous solution.This work also delves into the anticorrosion mechanism of MMA-BA and St-BA coatings.
文摘Objective To investigate the image quality, radiation dose and diagnostic value of the low-tube-voltage high-pitch dual-source computed tomography(DSCT) with sinogram affirmed iterative reconstruction(SAFIRE) for non-enhanced abdominal and pelvic scans. Methods This institutional review board-approved prospective study included 64 patients who gave written informed consent for additional abdominal and pelvic scan with DSCT in the period from November to December 2012. The patients underwent standard non-enhanced CT scans(protocol 1) [tube voltage of 120 k Vp/pitch of 0.9/filtered back-projection(FBP) reconstruction] followed by high-pitch non-enhanced CT scans(protocol 2)(100 k Vp/3.0/SAFIRE). The total scan time, mean CT number, signal-to-noise ratio(SNR), image quality, lesion detectability and radiation dose were compared between the two protocols. Results The total scan time of protocol 2 was significantly shorter than that of protocol 1(1.4±0.1 seconds vs. 7.6±0.6 seconds, P<0.001). There was no significant difference between protocol 1 and protocol 2 in mean CT number of all organs(liver, 55.4±6.3 HU vs. 56.1±6.8 HU, P=0.214; pancreas, 43.6±5.9 HU vs. 43.7±5.8 HU, P=0.785; spleen, 47.9±3.9 HU vs. 49.4±4.3 HU, P=0.128; kidney, 32.2±2.3 HU vs. 33.1±2.3 HU, P=0.367; abdominal aorta, 44.8±5.6 HU vs. 45.0±5.5 HU, P=0.499; psoas muscle, 50.7±4.1 HU vs. 50.3±4.5 HU, P=0.279). SNR on images of protocol 2 was higher than that of protocol 1(liver, 5.0±1.2 vs. 4.5±1.1, P<0.001; pancreas, 4.0±1.0 vs. 3.6±0.8, P<0.001; spleen, 4.7±1.0 vs. 4.1±0.9, P<0.001; kidney, 3.1±0.6 vs. 2.8±0.6, P<0.001; abdominal aorta, 4.1±1.0 vs. 3.8±1.0, P<0.001; psoas muscle, 4.5±1.1 vs. 4.3±1.2, P=0.012). The overall image noise of protocol 2 was lower than that of protocol1(9.8±3.1 HU vs. 11.1±3.0 HU, P<0.001). Image quality of protocol 2 was good but lower than that of protocol 1(4.1±0.7 vs. 4.6±0.5, P<0.001). Protocol 2 perceived 229 of 234 lesions(97.9%) that were detected in protocol 1 in the abdomen and pelvis. Radiation dose of protocol 2 was lower than that of protocol 1(4.4±0.4 m Sv vs. 7.3±2.4 m Sv, P<0.001) and the mean dose reduction was 41.4%. Conclusion The high-pitch DSCT with SAFIRE can shorten scan time and reduce radiation dose while preserving image quality in non-enhanced abdominal and pelvic scans.
基金Supported by the Ministry of Science and Technology of Inner Mongolia, China (20110504)
文摘Objective To prospectively investigate the diagnostic accuracy for coronary artery stenosis of prospectively electrocardiogram-triggered spiral acquisition mode (high pitch mode) dual-source computed tomography coronary angiography (CTCA) in patients with relatively higher heart rates (HR) compared with catheter coronary angiography (CCA). Methods Forty-seven consecutive patients with relatively higher HR (>65 and <100 bpm) (20 male, 27 female; age 55±10 years) who both underwent dual-source CTCA and CCA were prospectively included in this study. All patients were performed CTCA using high pitch mode setting at 20%-30% of the R-R interval for the image acquisition. All coronary segments were evaluated by two blinded and independent observers with regard to image quality on a three-point scale (1: excellent to 3: non-diagnostic) and for the presence of significant coronary stenoses (defined as diameter narrowing exceeding 50%). Considered CCA as the standard of reference, the sensitivity, specificity, positive predictive value and negative predictive value were calculated. Radiation dose values were calculated using the dose-length product. Results Image quality was rated as being score 1 in 92.4% of segments, score 2 in 6.1% of segmentsand score 3 in 1.5% of segments. The average image quality score per segment was 1.064±0.306. The HR variability of patients with image score 1, 2 and 3 were 2.29±1.06 bpm, 5.17±1.37 bpm, 8.88±1.53 bpm, respectively. The average HR variability of patients with different image scores were significantly different (F=170.402, P=0.001). The sensitivity, specificity, positive and negative predictive values were 92.6%, 97.0%, 87.6%, 98.3%, respectively, per segment and 90.0%, 95.2%, 85.3%, 96.9%, respectively, per vessel and 100%, 63.6%, 90.0%, 100%, respectively, per patient. The effective radiation dose was on average 0.86±0.16 mSv. Conclusion In patients with HR more than 65 bpm and below 100 bpm without cardiac arrhythmia, the prospectively electrocardiogram-gated high-pitch spiral acquisition mode with image acquired timing set at 20%-30% of the R-R interval provides a high diagnostic accuracy for the assessment of coronary stenoses combined with a 1.5% of non-diagnostic coronary segments and a radiation dose below 1 mSv.
基金Supported by the Ministry of Science and Technology of Inner Mongolia, China (20110504)
文摘Objective To investigate the feasibility of acquiring the similar homogeneous enhancement using bolus-tracking techniques with shortened respiratory time in prospectively electrocardiogram-gated high-pitch spiral acquisition mode (Flash mode) coronary computed tomography angiography (CCTA) compared with test bolus technique. Methods One hundred and eighty-four consecutive patients with mean heart rate ≤65 beats per minute undergoing CCTA were prospectively included in this study. The patients were randomly divided into two groups. Patients in the group A (n=92) instructed to shorten respiratory time received CCTA using bolus-tracking technique with high-pitch spiral acquisition mode (Flash mode), while those in the group B (n=92) underwent CCTA with test bolus technique. The attenuation in the ascending aorta, image noise, contrast-to-noise ratio and radiation doses of the two groups were assessed. Results There were no significant differences in the mean attenuation values in the ascending aorta (483.18±59.07 HU vs. 498.7±83.51 HU, P=0.183), image noise (21.4±4.5 HU vs. 20.9±4.3 HU, P=0.414), contrast-to-noise ratio (12.1±4.2 vs. 13.8±5.1, P=0.31) between the groups A and B. There were no significant differences in the radiation dose of dynamic monitoring scans (0.056±0.026 mSv vs. 0.062±0.018 mSv, P=0.068) and radiation dose of angiography (0.94±0.07 mSv vs. 0.96±0.15 mSv,P=0.926) between the two groups, while 15 mL less contrast material volume was administered in the group A than the group B. Conclusion Bolus-tracking technique with shortened time of respiratory in Flash mode of dual-source CT yields the similar homogeneous enhancement with less contrast material in comparison to the test bolus technique.
文摘Truncus arteriosus is an uncommon congenital cardiac abnormality which is characterized by a single arterial trunk origin from the heart that supplies both the systemic,pulmonary and coronary circulation.We present a preterm newborn female patient with type 2 truncusarteriosus,left superior vena cava and aberrant subclavian artery diagnosed with low dose dual-source cardiac computed tomography(CT).We discuss that low dose dual-source cardiac CT has more advantages than other imaging methods and it is an important modality for assessment of patients with conotruncal anomalies such as truncusarteriosus.
基金This study was approved by the Institutional Ethics Committee of West China Hospital,Sichuan University (Chengdu, Sichuan, ChinaNo. 14-163)+1 种基金This study has received funding by Sichuan Science and Technology Program(2020YJ0229)1⋅3⋅5 Project for Disciplines of Excellence,West China Hospital,Sichuan University(ZYGD18013)。
文摘Background:Pulmonary atresia(PA)is a group of heterogeneous complex congenital heart disease.Only one study modality might not get a correct diagnosis.This study aims to investigate the diagnostic power of dualsource computed tomography(DSCT)for all intracardiac and extracardiac deformities in patients with PA compared with transthoracic echocardiography(TTE).Materials and Methods:This retrospective study enrolled 79 patients and divided them into three groups according to their main diagnosis.All associated malformations and clinical information,including treatments,were recorded and compared among the three groups.The diagnostic power of DSCT and TTE on all associated malformations were compared.The surgical index(McGoon ratio,pulmonary arterials index(PAI),and total neopulmonary arterial index)and radiation dose were calculated on the basis of DSCT.Results:Of the patients,32,30,and 17 were divided into the groups of PA with ventricular septal defect(VSD),PA with VSD and major aortopulmonary collateral arteries,and PA with other major malformations,respectively.Consequently,182,162,and 13 intracardiac,extracardiac,and other major malformations were diagnosed,respectively.Moreover,DSCT showed a better diagnostic performance in extracardiac deformities(154 vs.117,p<0.001),whereas TTE could diagnose intracardiac deformities better(159 vs.139,p=0.001).The McGoon ratio,PAI,and treatment methods were significantly different among the three groups(p=0.014,p=0.008,and p=0.018,respectively).Conclusion:More than one imaging modality should be used to make a correct diagnosis when clinically suspecting PA.DSCT is superior to TTE in diagnosing extracardiac deformities and could be used to roughly calculate surgical indices to optimize treatment strategy.
