BACKGROUND Early thrombolytic therapy is crucial to treat acute cerebral infarction,especially since the onset of thrombolytic therapy takes 1-6 h.Therefore,early diagnosis and evaluation of cerebral infarction is imp...BACKGROUND Early thrombolytic therapy is crucial to treat acute cerebral infarction,especially since the onset of thrombolytic therapy takes 1-6 h.Therefore,early diagnosis and evaluation of cerebral infarction is important.AIM To investigate the diagnostic value of magnetic resonance multi-delay threedimensional arterial spin labeling(3DASL)and diffusion kurtosis imaging(DKI)in evaluating the perfusion and infarct area size in patients with acute cerebral ischemia.METHODS Eighty-four patients who experienced acute cerebral ischemia from March 2019 to February 2021 were included.All patients in the acute stage underwent magnetic resonance-based examination,and the data were processed by the system’s own software.The apparent diffusion coefficient(ADC),average diffusion coefficient(MD),axial diffusion(AD),radial diffusion(RD),average kurtosis(MK),radial kurtosis(fairly RK),axial kurtosis(AK),and perfusion parameters post-labeling delays(PLD)in the focal area and its corresponding area were compared.The correlation between the lesion area of cerebral infarction under MK and MD and T2-weighted imaging(T2WI)was analyzed.RESULTS The DKI parameters of focal and control areas in the study subjects were compared.The ADC,MD,AD,and RD values in the lesion area were significantly lower than those in the control area.The MK,RK,and AK values in the lesion area were significantly higher than those in the control area.The MK/MD value in the infarct lesions was used to determine the matching situation.MK/MD<5 mm was considered matching and MK/MD≥5 mm was considered mismatching.PLD1.5s and PLD2.5s perfusion parameters in the central,peripheral,and control areas of the infarct lesions in MK/MD-matched and-unmatched patients were not significantly different.PLD1.5s and PLD2.5s perfusion parameter values in the central area of the infarct lesions in MK/MD-matched and-unmatched patients were significantly lower than those in peripheral and control areas.The MK and MD maps showed a lesion area of 20.08±5.74 cm^(2) and 22.09±5.58 cm^(2),respectively.T2WI showed a lesion area of 19.76±5.02 cm^(2).There were no significant differences in the cerebral infarction lesion areas measured using the three methods.MK,MD,and T2WI showed a good correlation.CONCLUSION DKI parameters showed significant difference between the focal and control areas in patients with acute ischemic cerebral infarction.3DASL can effectively determine the changes in perfusion levels in the lesion area.There was a high correlation between the area of the infarct lesions diagnosed by DKI and T2WI.展开更多
Alzheimer’s disease (AD) is a dementing disorder and one of the major public health problems in countries with greater longevity. The cerebral cortical thickness and cerebral blood flow (CBF), which are considered as...Alzheimer’s disease (AD) is a dementing disorder and one of the major public health problems in countries with greater longevity. The cerebral cortical thickness and cerebral blood flow (CBF), which are considered as morphological and functional image features, respectively, could be decreased in specific cerebral regions of patients with dementia of Alzheimer type. Therefore, the aim of this study was to develop a computer-aided classification system for AD patients based on machine learning with the morphological and functional image features derived from a magnetic resonance (MR) imaging system. The cortical thicknesses in ten cerebral regions were derived as morphological features by using gradient vector trajectories in fuzzy membership images. Functional CBF maps were measured with an arterial spin labeling technique, and ten regional CBF values were obtained by registration between the CBF map and Talairach atlas using an affine transformation and a free form deformation. We applied two systems based on an arterial neural network (ANN) and a support vector machine (SVM), which were trained with 4 morphological and 6 functional image features, to 15 AD patients and 15 clinically normal (CN) subjects for classification of AD. The area under the receiver operating characteristic curve (AUC) values for the two systems based on the ANN and SVM with both image?features were 0.901 and 0.915, respectively. The AUC values for the ANN-and SVM-based systems with the morphological features were 0.710 and 0.660, respectively, and those with the functional features were 0.878 and 0.903, respectively. Our preliminary results suggest that the proposed method may have potential for assisting radiologists in the differential diagnosis of AD patients by using morphological and functional image features.展开更多
Endovascular surgery is advantageous in experimentally induced ischemic stroke because it causes fewer cranial traumatic lesions than invasive surgery and can closely mimic the pathophysiology in stroke patients. Howe...Endovascular surgery is advantageous in experimentally induced ischemic stroke because it causes fewer cranial traumatic lesions than invasive surgery and can closely mimic the pathophysiology in stroke patients. However, the outcomes are highly variable, which limits the accuracy of evaluations of ischemic stroke studies. In this study, eight healthy adult rhesus monkeys were randomized into two groups with four monkeys in each group： middle cerebral artery occlusion at origin segment （M1） and middle cerebral artery occlusion at M2 segment. The blood flow in the middle cerebral artery was blocked completely for 2 hours using the endovascular microcoil placement technique （1 mm × 10 cm） （undetachable）, to establish a model of cerebral ischemia. The microcoil was withdrawn and the middle cerebral artery blood flow was restored. A reversible middle cerebral artery occlusion model was identified by hematoxylin-eosin staining, digital subtraction angiography, magnetic resonance angiography, magnetic resonance imaging, and neurological evaluation. The results showed that the middle cerebral artery occlusion model was successfully established in eight adult healthy rhesus monkeys, and ischemic lesions were apparent in the brain tissue of rhesus monkeys at 24 hours after occlusion. The rhesus monkeys had symptoms of neurological deficits. Compared with the M1 occlusion group, the M2 occlusion group had lower infarction volume and higher neurological scores. These experimental findings indicate that reversible middle cerebral artery occlusion can be produced with the endovascular microcoil technique in rhesus monkeys. The M2 occluded model had less infarction and less neurological impairment, which offers the potential for application in the field of brain injury research.展开更多
Objective To investigate the role of sea-level cerebral blood flow(CBF)in predicting acute mountain sickness(AMS)using three-dimensional pseudo-continuous arterial spin labeling(3D-pCASL).Methods Forty-eight healthy v...Objective To investigate the role of sea-level cerebral blood flow(CBF)in predicting acute mountain sickness(AMS)using three-dimensional pseudo-continuous arterial spin labeling(3D-pCASL).Methods Forty-eight healthy volunteers reached an altitude of 3,650 m by air after undergoing a head magnetic resonance imaging(MRI)including 3D-pCASL at sea level.The CBF values of the bilateral anterior cerebral artery(ACA),middle cerebral artery(MCA),posterior cerebral artery(PCA),and posterior inferior cerebellar artery(PICA)territories and the laterality index(LI)of CBF were compared between the AMS and non-AMS groups.Statistical analyses were performed to determine the relationship between CBF and AMS,and the predictive performance was assessed using receiver operating characteristic(ROC)curves.Results The mean cortical CBF in women(81.65±2.69 mL/100 g/min)was higher than that in men(74.35±2.12 mL/100 g/min)(P<0.05).In men,the cortical CBF values in the bilateral ACA,PCA,PICA,and right MCA were higher in patients with AMS than in those without.Cortical CBF in the right PCA best predicted AMS(AUC=0.818).In women,the LI of CBF in the ACA was different between the AMS and non-AMS groups and predicted AMS with an AUC of 0.753.Conclusion Although the mechanism and prediction of AMS are quite complicated,higher cortical CBF at sea level,especially the CBF of the posterior circulatory system,may be used for prediction in male volunteers using non-invasive 3D-pCASL.展开更多
文摘BACKGROUND Early thrombolytic therapy is crucial to treat acute cerebral infarction,especially since the onset of thrombolytic therapy takes 1-6 h.Therefore,early diagnosis and evaluation of cerebral infarction is important.AIM To investigate the diagnostic value of magnetic resonance multi-delay threedimensional arterial spin labeling(3DASL)and diffusion kurtosis imaging(DKI)in evaluating the perfusion and infarct area size in patients with acute cerebral ischemia.METHODS Eighty-four patients who experienced acute cerebral ischemia from March 2019 to February 2021 were included.All patients in the acute stage underwent magnetic resonance-based examination,and the data were processed by the system’s own software.The apparent diffusion coefficient(ADC),average diffusion coefficient(MD),axial diffusion(AD),radial diffusion(RD),average kurtosis(MK),radial kurtosis(fairly RK),axial kurtosis(AK),and perfusion parameters post-labeling delays(PLD)in the focal area and its corresponding area were compared.The correlation between the lesion area of cerebral infarction under MK and MD and T2-weighted imaging(T2WI)was analyzed.RESULTS The DKI parameters of focal and control areas in the study subjects were compared.The ADC,MD,AD,and RD values in the lesion area were significantly lower than those in the control area.The MK,RK,and AK values in the lesion area were significantly higher than those in the control area.The MK/MD value in the infarct lesions was used to determine the matching situation.MK/MD<5 mm was considered matching and MK/MD≥5 mm was considered mismatching.PLD1.5s and PLD2.5s perfusion parameters in the central,peripheral,and control areas of the infarct lesions in MK/MD-matched and-unmatched patients were not significantly different.PLD1.5s and PLD2.5s perfusion parameter values in the central area of the infarct lesions in MK/MD-matched and-unmatched patients were significantly lower than those in peripheral and control areas.The MK and MD maps showed a lesion area of 20.08±5.74 cm^(2) and 22.09±5.58 cm^(2),respectively.T2WI showed a lesion area of 19.76±5.02 cm^(2).There were no significant differences in the cerebral infarction lesion areas measured using the three methods.MK,MD,and T2WI showed a good correlation.CONCLUSION DKI parameters showed significant difference between the focal and control areas in patients with acute ischemic cerebral infarction.3DASL can effectively determine the changes in perfusion levels in the lesion area.There was a high correlation between the area of the infarct lesions diagnosed by DKI and T2WI.
文摘Alzheimer’s disease (AD) is a dementing disorder and one of the major public health problems in countries with greater longevity. The cerebral cortical thickness and cerebral blood flow (CBF), which are considered as morphological and functional image features, respectively, could be decreased in specific cerebral regions of patients with dementia of Alzheimer type. Therefore, the aim of this study was to develop a computer-aided classification system for AD patients based on machine learning with the morphological and functional image features derived from a magnetic resonance (MR) imaging system. The cortical thicknesses in ten cerebral regions were derived as morphological features by using gradient vector trajectories in fuzzy membership images. Functional CBF maps were measured with an arterial spin labeling technique, and ten regional CBF values were obtained by registration between the CBF map and Talairach atlas using an affine transformation and a free form deformation. We applied two systems based on an arterial neural network (ANN) and a support vector machine (SVM), which were trained with 4 morphological and 6 functional image features, to 15 AD patients and 15 clinically normal (CN) subjects for classification of AD. The area under the receiver operating characteristic curve (AUC) values for the two systems based on the ANN and SVM with both image?features were 0.901 and 0.915, respectively. The AUC values for the ANN-and SVM-based systems with the morphological features were 0.710 and 0.660, respectively, and those with the functional features were 0.878 and 0.903, respectively. Our preliminary results suggest that the proposed method may have potential for assisting radiologists in the differential diagnosis of AD patients by using morphological and functional image features.
基金supported by grants from the National Key Basic Research Program(973 Program)of China,No.2011CB707804Beijing Municipal Science and Technology Project,No.2121100005312016
文摘Endovascular surgery is advantageous in experimentally induced ischemic stroke because it causes fewer cranial traumatic lesions than invasive surgery and can closely mimic the pathophysiology in stroke patients. However, the outcomes are highly variable, which limits the accuracy of evaluations of ischemic stroke studies. In this study, eight healthy adult rhesus monkeys were randomized into two groups with four monkeys in each group： middle cerebral artery occlusion at origin segment （M1） and middle cerebral artery occlusion at M2 segment. The blood flow in the middle cerebral artery was blocked completely for 2 hours using the endovascular microcoil placement technique （1 mm × 10 cm） （undetachable）, to establish a model of cerebral ischemia. The microcoil was withdrawn and the middle cerebral artery blood flow was restored. A reversible middle cerebral artery occlusion model was identified by hematoxylin-eosin staining, digital subtraction angiography, magnetic resonance angiography, magnetic resonance imaging, and neurological evaluation. The results showed that the middle cerebral artery occlusion model was successfully established in eight adult healthy rhesus monkeys, and ischemic lesions were apparent in the brain tissue of rhesus monkeys at 24 hours after occlusion. The rhesus monkeys had symptoms of neurological deficits. Compared with the M1 occlusion group, the M2 occlusion group had lower infarction volume and higher neurological scores. These experimental findings indicate that reversible middle cerebral artery occlusion can be produced with the endovascular microcoil technique in rhesus monkeys. The M2 occluded model had less infarction and less neurological impairment, which offers the potential for application in the field of brain injury research.
基金supported by the National Natural Science Foundation of China(No.81741115)Military Creative Project(No.16CXZ014)Military Healthcare Project(No.16BJZ11)。
文摘Objective To investigate the role of sea-level cerebral blood flow(CBF)in predicting acute mountain sickness(AMS)using three-dimensional pseudo-continuous arterial spin labeling(3D-pCASL).Methods Forty-eight healthy volunteers reached an altitude of 3,650 m by air after undergoing a head magnetic resonance imaging(MRI)including 3D-pCASL at sea level.The CBF values of the bilateral anterior cerebral artery(ACA),middle cerebral artery(MCA),posterior cerebral artery(PCA),and posterior inferior cerebellar artery(PICA)territories and the laterality index(LI)of CBF were compared between the AMS and non-AMS groups.Statistical analyses were performed to determine the relationship between CBF and AMS,and the predictive performance was assessed using receiver operating characteristic(ROC)curves.Results The mean cortical CBF in women(81.65±2.69 mL/100 g/min)was higher than that in men(74.35±2.12 mL/100 g/min)(P<0.05).In men,the cortical CBF values in the bilateral ACA,PCA,PICA,and right MCA were higher in patients with AMS than in those without.Cortical CBF in the right PCA best predicted AMS(AUC=0.818).In women,the LI of CBF in the ACA was different between the AMS and non-AMS groups and predicted AMS with an AUC of 0.753.Conclusion Although the mechanism and prediction of AMS are quite complicated,higher cortical CBF at sea level,especially the CBF of the posterior circulatory system,may be used for prediction in male volunteers using non-invasive 3D-pCASL.
