BACKGROUND Ankle fractures are common lesions of the lower limbs.Approximately 40%of ankle fractures affect the posterior malleolus(PM).Historically,PM osteosynthesis was recommended when PM size in X-ray images was g...BACKGROUND Ankle fractures are common lesions of the lower limbs.Approximately 40%of ankle fractures affect the posterior malleolus(PM).Historically,PM osteosynthesis was recommended when PM size in X-ray images was greater than 25%of the joint.Currently,computed tomography(CT)has been gaining traction in the preoperative evaluation of ankle fractures.AIM To elucidate the similarity in dimensions and to correlate PM size in X-ray images with the articular surface of the affected tibial plafond in the axial view on CT(AXCT)of a PM fracture.METHODS Eighty-one patients(mean age:39.4±13.5 years)were evaluated(54.3%were male).Two independent examiners measured PM size in profile X-ray images(PMXR)and sagittal CT(SAGCT)slices.The correlation of the measurements between the examiners and the difference in the PM fragment sizes between the two images were compared.Next,the PM size in PMXR was compared with the surface of the tibial plafond involved in the fracture in AXCT according to the Haraguchi classification.RESULTS The correlation rates between the examiners were 0.93 and 0.94 for PMXR and SAGCT,respectively(P<0.001).Fragments were 2.12%larger in SAGCT than in PMXR(P=0.018).In PMXR,there were 56 cases<25%and 25 cases≥25%.When PMXR was<25%,AXCT corresponded to 10.13%of the tibial plafond.When PMXR was≥25%,AXCT was 24.52%(P<0.001).According to the Haraguchi classification,fracture types I and II had similar PMXR measurements that were greater than those of type III.When analyzing AXCT,a significant difference was found between the three types,with II>I>III(P<0.001).CONCLUSION PM fractures show different sizes using X-ray or CT images.CT showed a larger PM in the sagittal plane and allowed the visualization of the real dimensions of the tibial plafond surface.展开更多
This paper demonstrates capabilities of low-field nuclear magnetic resonance (NMR) and microfocus X-ray computed tomography (μCT) in advanced, nondestructive, and quantitative characterization of pore types, producib...This paper demonstrates capabilities of low-field nuclear magnetic resonance (NMR) and microfocus X-ray computed tomography (μCT) in advanced, nondestructive, and quantitative characterization of pore types, producible porosity, pore structure, and spatial disposition of pore-fractures in coals. Results show that the NMR transverse relaxation time (T2) at 0.5–2.5, 20–50, and 】100 ms correspond to pores of 【0.1 μm, 】0.1 μm, and fractures, respectively. A much higher T2 spectrum peak reflects a much better development of pores (or fractures) corresponding to the T2, and vice versa. Three basic components in coals, i.e., the pores (or fractures), coal matrix, and minerals have their distinctive range of CT numbers. Among these, the CT number of pores is commonly less than 600 HU. The producible porosity, which is a determination of permeability, can be calculated by T2 cutoff value (T2C) of coal NMR. The coal pore structure can be efficiently estimated by the newly proposed "T2C based model". Finally, μCT scan was proven capable of modeling and spatial visualization of pores and fractures.展开更多
AIM:To assess radiologists reporting rates of incidental vertebral compression fractures in imaging studies. METHODS:We performed a review of the current literature on the prevalence and reporting rates of incidental ...AIM:To assess radiologists reporting rates of incidental vertebral compression fractures in imaging studies. METHODS:We performed a review of the current literature on the prevalence and reporting rates of incidental vertebral compression fractures in radiologic examinations. RESULTS:The bibliographic search revealed 12 studies:7 studies using conventional radiology and 5 using multidetector computed tomography(MDCT).The lossof height cut-off to define a vertebral fracture varied from 15%to 25%.Fracture prevalence was high (mean 21.1%;range 9.5%-35%)in both radiographic and MDCT studies(mean 21.6%and 20.2%,respectively).Reporting rates were low with a mean value of 27.4%(range 0%-66.3%)and were significantly lower in MDCT than in radiographic studies(mean 8.1%vs 41.1%).Notably,recent studies showed lower reporting rates than older studies. CONCLUSION:Many scientific studies have confirmed a high prevalence of vertebral compression fractures as incidental findings on imaging studies.However,the underreporting of these fractures,as determined in our study,may negatively affect patient care.展开更多
Purpose: Pelvic fracture evaluation with abdominopelvic computed tomography (CT) and formal CT cystography for rule out of urine bladder injury have been commonly employed in pediatric trauma patients. The additional ...Purpose: Pelvic fracture evaluation with abdominopelvic computed tomography (CT) and formal CT cystography for rule out of urine bladder injury have been commonly employed in pediatric trauma patients. The additional delayed imaging required to obtain optimal CT cystography is, however, associated with increased doses of ionizing radiation to pelvic organs and represent a significant risk in the pediatric population for future carcinogenic risk. We hypothesized that avoidance of routine CT cystography among pediatric pelvic fracture victims would not result in an appreciable rate of missed bladder injuries and would aid in mitigating the radiation exposure risk associated with these additional images.Methods: A retrospective cohort study involving blunt trauma pelvic fractures among pediatric trauma patients (age<14) between the years 1997 and 2016 was conducted utilizing the Israeli National Trauma Registry. Statistical analysis was performed using SAS statistical software version 9.4 via the tests of Chisquare test and two-sided Fisher’s exact test. Ap value of less than 0.05 was considered statistically significant.Results: A total of 1072 children were identified from the registry for inclusion. Mean age of patients was 7.7 years (range 0-14) and 713 (66.5%) were male. Overall mortality in this population was 4.1% (44/1072). Only 2.1% (23) of pediatric patients with pelvic fractures had bladder injury identified, with just 9 children having intraperitoneal bladder rupture (0.8% of all the patients).Conclusion: The vast majority of blunt pediatric trauma victims with pelvic fractures do not have urine bladder injuries. Based on our study results we do not recommend the routine utilization of CT cystography in this unique population.展开更多
It is inadequate to study the shear failure anisotropy of shale in only 2D space.Aiming at a 3D analysis,a series of direct shear tests was conducted on Longmaxi shale with three typical bedding orientations:arrester,...It is inadequate to study the shear failure anisotropy of shale in only 2D space.Aiming at a 3D analysis,a series of direct shear tests was conducted on Longmaxi shale with three typical bedding orientations:arrester,divider and short-transverse orientations.During testing,acoustic emission(AE)and digital image correlation(DIC)techniques were simultaneously employed to monitor failure development,after testing,X-ray computed tomography(CT)scanning was adopted to acquire and reconstruct the fractures inside typical ruptured samples for more detailed analysis.The results indicated that the shear strength parameters exhibited 3D anisotropies and those of the arrester sample did not have equivalent shear strength parameters to the shale matrix.The maximum(minimum)shear strength and cohesion were obtained with the divider(short-transverse)orientation,and the internal friction angle reached its maximum(minimum)with the divider(arrester)orientation.Combining the AE,DIC and CT techniques,four characteristic stress levels that can capture the progressive shear failure process of shale rocks were identified,and the onset and accelerated development of shear damage-induced dilation were observed at the crack initiation and coalesce stress thresholds,respectively.During the crack coalescence stage,the dominated microcracking mechanism transferred from tensile-mode to shear-mode.For the arrester and divider orientations,more tensile-mode AE events were generated due to the microcracking along the vertical beddings.Compared with the divider samples,a more complex fracture network with a larger fracture area and volume was obtained in the arrester samples,whose strengths were smaller.展开更多
文摘BACKGROUND Ankle fractures are common lesions of the lower limbs.Approximately 40%of ankle fractures affect the posterior malleolus(PM).Historically,PM osteosynthesis was recommended when PM size in X-ray images was greater than 25%of the joint.Currently,computed tomography(CT)has been gaining traction in the preoperative evaluation of ankle fractures.AIM To elucidate the similarity in dimensions and to correlate PM size in X-ray images with the articular surface of the affected tibial plafond in the axial view on CT(AXCT)of a PM fracture.METHODS Eighty-one patients(mean age:39.4±13.5 years)were evaluated(54.3%were male).Two independent examiners measured PM size in profile X-ray images(PMXR)and sagittal CT(SAGCT)slices.The correlation of the measurements between the examiners and the difference in the PM fragment sizes between the two images were compared.Next,the PM size in PMXR was compared with the surface of the tibial plafond involved in the fracture in AXCT according to the Haraguchi classification.RESULTS The correlation rates between the examiners were 0.93 and 0.94 for PMXR and SAGCT,respectively(P<0.001).Fragments were 2.12%larger in SAGCT than in PMXR(P=0.018).In PMXR,there were 56 cases<25%and 25 cases≥25%.When PMXR was<25%,AXCT corresponded to 10.13%of the tibial plafond.When PMXR was≥25%,AXCT was 24.52%(P<0.001).According to the Haraguchi classification,fracture types I and II had similar PMXR measurements that were greater than those of type III.When analyzing AXCT,a significant difference was found between the three types,with II>I>III(P<0.001).CONCLUSION PM fractures show different sizes using X-ray or CT images.CT showed a larger PM in the sagittal plane and allowed the visualization of the real dimensions of the tibial plafond surface.
基金supported by National Major Research Program for Science and Technology of China (Grant Nos. 2008ZX05034-01 and 2008ZX05062-001)National Basic Research Program of China (Grant No. 2009CB219604)+2 种基金National Natural Science Foundation of China (Grant No. 40972107)Petro China Innovation Foundation (Grant No. 2008D-5006-01-04)Program for Changjiang Scholars and Innovative Research Team in University (Grant No. IRT0864)
文摘This paper demonstrates capabilities of low-field nuclear magnetic resonance (NMR) and microfocus X-ray computed tomography (μCT) in advanced, nondestructive, and quantitative characterization of pore types, producible porosity, pore structure, and spatial disposition of pore-fractures in coals. Results show that the NMR transverse relaxation time (T2) at 0.5–2.5, 20–50, and 】100 ms correspond to pores of 【0.1 μm, 】0.1 μm, and fractures, respectively. A much higher T2 spectrum peak reflects a much better development of pores (or fractures) corresponding to the T2, and vice versa. Three basic components in coals, i.e., the pores (or fractures), coal matrix, and minerals have their distinctive range of CT numbers. Among these, the CT number of pores is commonly less than 600 HU. The producible porosity, which is a determination of permeability, can be calculated by T2 cutoff value (T2C) of coal NMR. The coal pore structure can be efficiently estimated by the newly proposed "T2C based model". Finally, μCT scan was proven capable of modeling and spatial visualization of pores and fractures.
文摘AIM:To assess radiologists reporting rates of incidental vertebral compression fractures in imaging studies. METHODS:We performed a review of the current literature on the prevalence and reporting rates of incidental vertebral compression fractures in radiologic examinations. RESULTS:The bibliographic search revealed 12 studies:7 studies using conventional radiology and 5 using multidetector computed tomography(MDCT).The lossof height cut-off to define a vertebral fracture varied from 15%to 25%.Fracture prevalence was high (mean 21.1%;range 9.5%-35%)in both radiographic and MDCT studies(mean 21.6%and 20.2%,respectively).Reporting rates were low with a mean value of 27.4%(range 0%-66.3%)and were significantly lower in MDCT than in radiographic studies(mean 8.1%vs 41.1%).Notably,recent studies showed lower reporting rates than older studies. CONCLUSION:Many scientific studies have confirmed a high prevalence of vertebral compression fractures as incidental findings on imaging studies.However,the underreporting of these fractures,as determined in our study,may negatively affect patient care.
文摘Purpose: Pelvic fracture evaluation with abdominopelvic computed tomography (CT) and formal CT cystography for rule out of urine bladder injury have been commonly employed in pediatric trauma patients. The additional delayed imaging required to obtain optimal CT cystography is, however, associated with increased doses of ionizing radiation to pelvic organs and represent a significant risk in the pediatric population for future carcinogenic risk. We hypothesized that avoidance of routine CT cystography among pediatric pelvic fracture victims would not result in an appreciable rate of missed bladder injuries and would aid in mitigating the radiation exposure risk associated with these additional images.Methods: A retrospective cohort study involving blunt trauma pelvic fractures among pediatric trauma patients (age<14) between the years 1997 and 2016 was conducted utilizing the Israeli National Trauma Registry. Statistical analysis was performed using SAS statistical software version 9.4 via the tests of Chisquare test and two-sided Fisher’s exact test. Ap value of less than 0.05 was considered statistically significant.Results: A total of 1072 children were identified from the registry for inclusion. Mean age of patients was 7.7 years (range 0-14) and 713 (66.5%) were male. Overall mortality in this population was 4.1% (44/1072). Only 2.1% (23) of pediatric patients with pelvic fractures had bladder injury identified, with just 9 children having intraperitoneal bladder rupture (0.8% of all the patients).Conclusion: The vast majority of blunt pediatric trauma victims with pelvic fractures do not have urine bladder injuries. Based on our study results we do not recommend the routine utilization of CT cystography in this unique population.
基金This research was funded by the National Natural Science Foundation of China(No.12172240 and No.51704198)Department of Science and Technology of Sichuan Province(No.2021YFH0030).
文摘It is inadequate to study the shear failure anisotropy of shale in only 2D space.Aiming at a 3D analysis,a series of direct shear tests was conducted on Longmaxi shale with three typical bedding orientations:arrester,divider and short-transverse orientations.During testing,acoustic emission(AE)and digital image correlation(DIC)techniques were simultaneously employed to monitor failure development,after testing,X-ray computed tomography(CT)scanning was adopted to acquire and reconstruct the fractures inside typical ruptured samples for more detailed analysis.The results indicated that the shear strength parameters exhibited 3D anisotropies and those of the arrester sample did not have equivalent shear strength parameters to the shale matrix.The maximum(minimum)shear strength and cohesion were obtained with the divider(short-transverse)orientation,and the internal friction angle reached its maximum(minimum)with the divider(arrester)orientation.Combining the AE,DIC and CT techniques,four characteristic stress levels that can capture the progressive shear failure process of shale rocks were identified,and the onset and accelerated development of shear damage-induced dilation were observed at the crack initiation and coalesce stress thresholds,respectively.During the crack coalescence stage,the dominated microcracking mechanism transferred from tensile-mode to shear-mode.For the arrester and divider orientations,more tensile-mode AE events were generated due to the microcracking along the vertical beddings.Compared with the divider samples,a more complex fracture network with a larger fracture area and volume was obtained in the arrester samples,whose strengths were smaller.
