Tomographic perfusion imaging is a significant imaging modality for stroke diagnosis.However,the low rotational speed of the C-arm(6–8 s per circle)is a challenge for applying perfusion imaging in C-arm cone beam com...Tomographic perfusion imaging is a significant imaging modality for stroke diagnosis.However,the low rotational speed of the C-arm(6–8 s per circle)is a challenge for applying perfusion imaging in C-arm cone beam computed tomography(CBCT).Traditional reconstruction methods cannot remove the artifacts caused by the slow rotational speed or acquire enough sample points to restore the time density curve(TDC).This paper presents a dynamic rollback reconstruction method for CBCT.The proposed method can improve the temporal resolution by increasing the sample points used for calculating the TDC.Combined with existing techniques,the algorithm allows slow-rotating scanners to be used for perfusion imaging purposes.In the experiments,the proposed method was compared with other dynamic reconstruction algorithms based on standard reconstruction and the temporal interpolation approach.The presented algorithm could improve the temporal resolution without increasing the X-ray exposure time or contrast agent.展开更多
Objective To determine the characteristics of intracranial plaque proximal to large vessel occlusion(LVO)in stroke patients without major-risk cardioembolic source using 3.0 T high-resolution MRI(HR-MRI).Methods We re...Objective To determine the characteristics of intracranial plaque proximal to large vessel occlusion(LVO)in stroke patients without major-risk cardioembolic source using 3.0 T high-resolution MRI(HR-MRI).Methods We retrospectively enrolled eligible patients from January 2015 to July 2021.The multidimensional parameters of plaque such as remodelling index(RI),plaque burden(PB),percentage lipid-rich necrotic core(%LRNC),presence of discontinuity of plaque surface(DPS),fibrous cap rupture,intraplaque haemorrhage and complicated plaque were evaluated by HR-MRI.Results Among 279 stroke patients,intracranial plaque proximal to LVO was more prevalent in the ipsilateral versus contralateral side to stroke(75.6%vs 58.8%,p<0.001).The larger PB(p<0.001),RI(p<0.001)and%LRNC(p=0.001),the higher prevalence of DPS(61.1%vs 50.6%,p=0.041)and complicated plaque(63.0%vs 50.6%,p=0.016)were observed in the plaque ipsilateral versus contralateral to stroke.Logistic analysis showed that RI and PB were positively associated with an ischaemic stroke(RI:crude OR:1.303,95%CI 1.072 to 1.584,p=0.008;PB:crude OR:1.677,95%CI 1.381 to 2.037,p<0.001).In subgroup with<50%stenotic plaque,the greater PB,RI,%LRNC and the presence of complicated plaque were more closely related to stroke,which was not evident in subgroup with≥50%stenotic plaque.Conclusion This is the first study to report the characteristics of intracranial plaque proximal to LVO in non-cardioembolic stroke.It provides potential evidence to support different aetiological roles of<50%stenotic vs≥50%stenotic intracranial plaque in this population.展开更多
基金supported in part by the State’s Key Project of Research and Development Plan (Nos. 2017YFC0109202,2017YFA0104302)the National Natural Science Foundation (No.61871117)Science and Technology Program of Guangdong (No.2018B030333001)。
文摘Tomographic perfusion imaging is a significant imaging modality for stroke diagnosis.However,the low rotational speed of the C-arm(6–8 s per circle)is a challenge for applying perfusion imaging in C-arm cone beam computed tomography(CBCT).Traditional reconstruction methods cannot remove the artifacts caused by the slow rotational speed or acquire enough sample points to restore the time density curve(TDC).This paper presents a dynamic rollback reconstruction method for CBCT.The proposed method can improve the temporal resolution by increasing the sample points used for calculating the TDC.Combined with existing techniques,the algorithm allows slow-rotating scanners to be used for perfusion imaging purposes.In the experiments,the proposed method was compared with other dynamic reconstruction algorithms based on standard reconstruction and the temporal interpolation approach.The presented algorithm could improve the temporal resolution without increasing the X-ray exposure time or contrast agent.
文摘Objective To determine the characteristics of intracranial plaque proximal to large vessel occlusion(LVO)in stroke patients without major-risk cardioembolic source using 3.0 T high-resolution MRI(HR-MRI).Methods We retrospectively enrolled eligible patients from January 2015 to July 2021.The multidimensional parameters of plaque such as remodelling index(RI),plaque burden(PB),percentage lipid-rich necrotic core(%LRNC),presence of discontinuity of plaque surface(DPS),fibrous cap rupture,intraplaque haemorrhage and complicated plaque were evaluated by HR-MRI.Results Among 279 stroke patients,intracranial plaque proximal to LVO was more prevalent in the ipsilateral versus contralateral side to stroke(75.6%vs 58.8%,p<0.001).The larger PB(p<0.001),RI(p<0.001)and%LRNC(p=0.001),the higher prevalence of DPS(61.1%vs 50.6%,p=0.041)and complicated plaque(63.0%vs 50.6%,p=0.016)were observed in the plaque ipsilateral versus contralateral to stroke.Logistic analysis showed that RI and PB were positively associated with an ischaemic stroke(RI:crude OR:1.303,95%CI 1.072 to 1.584,p=0.008;PB:crude OR:1.677,95%CI 1.381 to 2.037,p<0.001).In subgroup with<50%stenotic plaque,the greater PB,RI,%LRNC and the presence of complicated plaque were more closely related to stroke,which was not evident in subgroup with≥50%stenotic plaque.Conclusion This is the first study to report the characteristics of intracranial plaque proximal to LVO in non-cardioembolic stroke.It provides potential evidence to support different aetiological roles of<50%stenotic vs≥50%stenotic intracranial plaque in this population.
