By means of advantages of both SAR and lidar, the combination of the techniques of (inverse) synthetic aperture and lidar makes it possible to obtain high resolution 2-D image. In this paper, an indoor experimental sy...By means of advantages of both SAR and lidar, the combination of the techniques of (inverse) synthetic aperture and lidar makes it possible to obtain high resolution 2-D image. In this paper, an indoor experimental system of inverse synthetic aperture lidar imaging is given and a processing approach is presented. The given system is in the mode of lidar system with separated receiver and transmitter, which can effectively eliminate the jamming from the lens or/and the intersection between two optic fibers. Based on the reference channel techniques, a method for the compensation of nonlinear frequency in the time domain is presented, which can solve the problem of nonlinear frequency efficiently. Then, with the mature inverse synthetic aperture algorithm, an image of inverse synthetic aperture lidar can be obtained, which is the first attempt in China. Finally, experimental results confirm the validity of the presented method and the feasibility of the experimental system.展开更多
Tensor interpolation is a key step in the processing algorithms of diffusion tensor imaging (DTI), such as registration and tractography. The diffusion tensor (DT) in biological tissues is assumed to be positive defin...Tensor interpolation is a key step in the processing algorithms of diffusion tensor imaging (DTI), such as registration and tractography. The diffusion tensor (DT) in biological tissues is assumed to be positive definite. However, the tensor interpolations in most clinical applications have used a Euclidian scheme that does not take this assumption into account. Several Rie-mannian schemes were developed to overcome this limitation. Although each of the Riemannian schemes uses different metrics, they all result in a ‘fixed’ interpolation profile that cannot adapt to a variety of diffusion patterns in biological tissues. In this paper, we propose a DT interpolation scheme to control the interpolation profile, and explore its feasibility in clinical applications. The profile controllability comes from the non-uniform motion of interpolation on the Riemannian geodesic. The interpolation experiment with medical DTI data shows that the profile control improves the interpolation quality by assessing the reconstruction errors with the determinant error, Euclidean norm, and Riemannian norm.展开更多
AIM: To investigating the relationship between thoracic and cardiac <sup>18</sup>F-Natrium-Fluoride (18F-NaF) uptake, as a marker of ongoing calcification and cardiovascular risk factors.METHODS: Seventy-e...AIM: To investigating the relationship between thoracic and cardiac <sup>18</sup>F-Natrium-Fluoride (18F-NaF) uptake, as a marker of ongoing calcification and cardiovascular risk factors.METHODS: Seventy-eight patients (44 females, mean age 63, range 44-83) underwent whole body 18F-NaF positron emission tomography/computed tomography. Cardiovascular risk (CVR) was used to divide these patients in three categories: Low (LR), medium (MR) and high risk (HR). 18F-NaF uptake was measured by manually drawing volumes of interest on the ascending aorta, on the aortic arch, on the descending aorta and on the myocardium; average standardized uptake value was normalized for blood-pool, to obtain target-to-background ratio (TBR). Values from the three aortic segments were then averaged to obtain an index of the whole thoracic aorta.RESULTS: A significant difference in whole thoracic aorta TBR was detected between HR and LR (1.84 ± 0.76 vs 1.07 ± 0.3, P < 0.001), but also between MR and HR-LR (1.4 ± 0.4, P < 0.02 and P < 0.01, respectively). Significance of this TBR stratification strongly varied among thoracic aorta subsegments and the lowest P values were reached in the descending aorta (P < 0.01). Myocardial uptake provided an effective CVR classes stratification (P < 0.001).Correlation between TBR and CVR was appreciable when the whole thoracic aorta was considered (R = 0.67), but it peaked when correlating the descending thoracic segment (R = 0.75), in comparison with the aortic arch and the ascending segment (R = 0.55 and 0.53, respectively).CONCLUSION: Fluoride uptake within the thoracic aorta wall effectively depicts patients’ risk class and correlates with cardiovascular risk. Descending aorta is the most effective in CVR determination.展开更多
BACKGROUND A 70-year-old man with hepatitis C virus-related recurrent hepatocellular carcinoma was admitted for further diagnosis of a 1 cm iso-hyperechoic nodule in segment(S)5.CASE SUMMARY Gadolinium ethoxybenzyl di...BACKGROUND A 70-year-old man with hepatitis C virus-related recurrent hepatocellular carcinoma was admitted for further diagnosis of a 1 cm iso-hyperechoic nodule in segment(S)5.CASE SUMMARY Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging(EOB-MRI)revealed the nodule in S5 with a defect at the hepatobiliary phase,hyperintensity on diffusion weighted imaging(DWI)and hypointensity on apparent diffusion coefficient(ADC)map.Contrast-enhanced computed tomography revealed hypervascularity at the early phase,and delayed contrast-enhancement was observed at the late phase.Contrast-enhanced ultrasound(US)revealed incomplete defect at the late vascular phase.Inflammatory liver tumor,lymphoproliferative disease,intrahepatic cholangiocarcinoma(small duct type)and bile duct adenoma were suspected through the imaging studies.US guided biopsy,however,showed a noncaseating hepatic sarcoid-like epithelioid granuloma(HSEG),and histopathological analysis disclosed spindle shaped epithelioid cells harboring Langhans-type multinucleated giant cells.One month after admission,EOB-MRI signaled the disappearance of the defect at the hepatobiliary phase,of hyperintensity on DWI,of hypointensity on ADC map,and no stain at the early phase.CONCLUSION That the patient had received BNT162b2 messenger RNA(mRNA)coronavirus disease 2019 vaccination 3 mo before the occurrence of HSEG,and that its disappearance was confirmed 4 mo after mRNA vaccination suggested that the drug-induced sarcoidosis-like reaction(DISR)might be induced by the mRNA vaccination.Fortunately,rechallenge of drug-induced DISR with the third mRNA vaccination was not confirmed.展开更多
基金Supported by the National High Technology Research and Development Program of China ("863" Program) (Grant No. 2006AA12Z144)
文摘By means of advantages of both SAR and lidar, the combination of the techniques of (inverse) synthetic aperture and lidar makes it possible to obtain high resolution 2-D image. In this paper, an indoor experimental system of inverse synthetic aperture lidar imaging is given and a processing approach is presented. The given system is in the mode of lidar system with separated receiver and transmitter, which can effectively eliminate the jamming from the lens or/and the intersection between two optic fibers. Based on the reference channel techniques, a method for the compensation of nonlinear frequency in the time domain is presented, which can solve the problem of nonlinear frequency efficiently. Then, with the mature inverse synthetic aperture algorithm, an image of inverse synthetic aperture lidar can be obtained, which is the first attempt in China. Finally, experimental results confirm the validity of the presented method and the feasibility of the experimental system.
基金Project (No. 60772092) supported by the National Natural Science Foundation of China
文摘Tensor interpolation is a key step in the processing algorithms of diffusion tensor imaging (DTI), such as registration and tractography. The diffusion tensor (DT) in biological tissues is assumed to be positive definite. However, the tensor interpolations in most clinical applications have used a Euclidian scheme that does not take this assumption into account. Several Rie-mannian schemes were developed to overcome this limitation. Although each of the Riemannian schemes uses different metrics, they all result in a ‘fixed’ interpolation profile that cannot adapt to a variety of diffusion patterns in biological tissues. In this paper, we propose a DT interpolation scheme to control the interpolation profile, and explore its feasibility in clinical applications. The profile controllability comes from the non-uniform motion of interpolation on the Riemannian geodesic. The interpolation experiment with medical DTI data shows that the profile control improves the interpolation quality by assessing the reconstruction errors with the determinant error, Euclidean norm, and Riemannian norm.
文摘AIM: To investigating the relationship between thoracic and cardiac <sup>18</sup>F-Natrium-Fluoride (18F-NaF) uptake, as a marker of ongoing calcification and cardiovascular risk factors.METHODS: Seventy-eight patients (44 females, mean age 63, range 44-83) underwent whole body 18F-NaF positron emission tomography/computed tomography. Cardiovascular risk (CVR) was used to divide these patients in three categories: Low (LR), medium (MR) and high risk (HR). 18F-NaF uptake was measured by manually drawing volumes of interest on the ascending aorta, on the aortic arch, on the descending aorta and on the myocardium; average standardized uptake value was normalized for blood-pool, to obtain target-to-background ratio (TBR). Values from the three aortic segments were then averaged to obtain an index of the whole thoracic aorta.RESULTS: A significant difference in whole thoracic aorta TBR was detected between HR and LR (1.84 ± 0.76 vs 1.07 ± 0.3, P < 0.001), but also between MR and HR-LR (1.4 ± 0.4, P < 0.02 and P < 0.01, respectively). Significance of this TBR stratification strongly varied among thoracic aorta subsegments and the lowest P values were reached in the descending aorta (P < 0.01). Myocardial uptake provided an effective CVR classes stratification (P < 0.001).Correlation between TBR and CVR was appreciable when the whole thoracic aorta was considered (R = 0.67), but it peaked when correlating the descending thoracic segment (R = 0.75), in comparison with the aortic arch and the ascending segment (R = 0.55 and 0.53, respectively).CONCLUSION: Fluoride uptake within the thoracic aorta wall effectively depicts patients’ risk class and correlates with cardiovascular risk. Descending aorta is the most effective in CVR determination.
文摘BACKGROUND A 70-year-old man with hepatitis C virus-related recurrent hepatocellular carcinoma was admitted for further diagnosis of a 1 cm iso-hyperechoic nodule in segment(S)5.CASE SUMMARY Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging(EOB-MRI)revealed the nodule in S5 with a defect at the hepatobiliary phase,hyperintensity on diffusion weighted imaging(DWI)and hypointensity on apparent diffusion coefficient(ADC)map.Contrast-enhanced computed tomography revealed hypervascularity at the early phase,and delayed contrast-enhancement was observed at the late phase.Contrast-enhanced ultrasound(US)revealed incomplete defect at the late vascular phase.Inflammatory liver tumor,lymphoproliferative disease,intrahepatic cholangiocarcinoma(small duct type)and bile duct adenoma were suspected through the imaging studies.US guided biopsy,however,showed a noncaseating hepatic sarcoid-like epithelioid granuloma(HSEG),and histopathological analysis disclosed spindle shaped epithelioid cells harboring Langhans-type multinucleated giant cells.One month after admission,EOB-MRI signaled the disappearance of the defect at the hepatobiliary phase,of hyperintensity on DWI,of hypointensity on ADC map,and no stain at the early phase.CONCLUSION That the patient had received BNT162b2 messenger RNA(mRNA)coronavirus disease 2019 vaccination 3 mo before the occurrence of HSEG,and that its disappearance was confirmed 4 mo after mRNA vaccination suggested that the drug-induced sarcoidosis-like reaction(DISR)might be induced by the mRNA vaccination.Fortunately,rechallenge of drug-induced DISR with the third mRNA vaccination was not confirmed.
