High-resolution images of human brain are critical for monitoring the neurological conditions in a portable and safe manner.Sound speed mapping of brain tissues provides unique information for such a purpose.In additi...High-resolution images of human brain are critical for monitoring the neurological conditions in a portable and safe manner.Sound speed mapping of brain tissues provides unique information for such a purpose.In addition,it is particularly important for building digital human acoustic models,which form a reference for future ultrasound research.Conventional ultrasound modalities can hardly image the human brain at high spatial resolution inside the skull due to the strong impedance contrast between hard tissue and soft tissue.We carry out numerical experiments to demonstrate that the time-domain waveform inversion technique,originating from the geophysics community,is promising to deliver quantitative images of human brains within the skull at a sub-millimeter level by using ultra-sound signals.The successful implementation of such an approach to brain imaging requires the following items:signals of sub-megahertz frequencies transmitting across the inside of skull,an accurate numerical wave equation solver simulating the wave propagation,and well-designed inversion schemes to reconstruct the physical parameters of targeted model based on the optimization theory.Here we propose an innovative modality of multiscale deconvolutional waveform inversion that improves ultrasound imaging resolution,by evaluating the similarity between synthetic data and observed data through using limited length Wiener filter.We implement the proposed approach to iteratively update the parametric models of the human brain.The quantitative imaging method paves the way for building the accurate acoustic brain model to diagnose associated diseases,in a potentially more portable,more dynamic and safer way than magnetic resonance imaging and x-ray computed tomography.展开更多
The brain is protected from the entry of foreign substances by blood-brain barrier (BBB), but becomes a barrier while chemotherapy is needed for the brain diseases. Ultrasound with microbubbles (MBs) has been shown to...The brain is protected from the entry of foreign substances by blood-brain barrier (BBB), but becomes a barrier while chemotherapy is needed for the brain diseases. Ultrasound with microbubbles (MBs) has been shown to noninvasively increase the permeability of the BBB in the normal tissue and brain tumor. The real mechanism for disruption is still unknown. Hemorrhage was usually found in the sonicated region of the brain. Thus, treatment safety is the primary concern when considering clinical application of BBB disruption induced by ultrasound in the presence of MBs. Here we investigate the effects of ultrasound on the permeability of BBB whether the MBs were administered. The data reveals that Evans blue (EB) accumulation was highest in the brain after sonication with MBs. However, the permeability of BBB also can be significantly increased by ultrasound alone. These results demonstrated that noninvasive disruption of BBB by ultrasound alone with no damage is possible.展开更多
<strong>Objective</strong><span style="font-family:;" "=""><span style="font-family:Verdana;"><strong>: </strong>To evaluate the clinical value of...<strong>Objective</strong><span style="font-family:;" "=""><span style="font-family:Verdana;"><strong>: </strong>To evaluate the clinical value of transcranial color Doppler ultrasound (TCCD) in assessing cerebral function after cardiopulmonary resuscitation (CPR). </span><b><span style="font-family:Verdana;">Methods</span></b><span style="font-family:Verdana;">: A prospective study was conducted in 52 patients with cardiac arrest treated by CPR from January 2018 to January 2020, and its clinical data were analyzed</span></span><span style="font-family:Verdana;">. </span><span style="font-family:;" "=""><span style="font-family:Verdana;">According to classification of cerebral performance category (CPC), 31 cases (CPC grade 1 - 2) were selected in the good prognosis group and 21 cases (CPC grade 3 - 5) in the poor prognosis group. The cerebral blood flow was measured by transcranial Doppler ultrasound (TCCD) 24 h after CPR, and the differences were compared between the two groups in stroke index, diastolic blood flow velocity (Vd), systolic peak blood flow velocity (Vs) and mean peak blood flow velocity (Vm). The ROC curve of cerebral blood flow after CPR was drawn to predict the prognosis of brain function. </span><b><span style="font-family:Verdana;">Results</span></b><span style="font-family:Verdana;">: The data showed that the pulsatility index of middle cerebral artery of the poor prognosis group decreased within 24 h</span></span><span style="font-family:Verdana;">;</span><span style="font-family:Verdana;">the difference between the two groups was statistically significant (p < 0.05);the Vd, Vs, Vm increased in the good prognosis group</span><span style="font-family:Verdana;">;</span><span style="font-family:;" "=""><span style="font-family:Verdana;">the difference between the two groups was statistically significant (p < 0.05). The ROC curve of cerebral blood flow after CPR was drawn to predict the prognosis of brain function, and the results showed that the area under the curve and the optimal critical value of cerebral blood flow were 0.731 and 5.69. The sensitivity and specificity were 67.3% and 79.1% respectively. </span><b><span style="font-family:Verdana;">Conclusion</span></b><span style="font-family:Verdana;">: The cerebral blood flow increase in the early stage of successful CPR is positively correlated with the prognosis of cerebral functional resuscitation. Monitoring intracranial blood flow after CPR by TCCD has clinical value to evaluate prognosis of brain function.</span></span>展开更多
基金Project supported by the Goal-Oriented Project Independently Deployed by Institute of Acoustics,Chinese Academy of Sciences (Grant No.MBDX202113)。
文摘High-resolution images of human brain are critical for monitoring the neurological conditions in a portable and safe manner.Sound speed mapping of brain tissues provides unique information for such a purpose.In addition,it is particularly important for building digital human acoustic models,which form a reference for future ultrasound research.Conventional ultrasound modalities can hardly image the human brain at high spatial resolution inside the skull due to the strong impedance contrast between hard tissue and soft tissue.We carry out numerical experiments to demonstrate that the time-domain waveform inversion technique,originating from the geophysics community,is promising to deliver quantitative images of human brains within the skull at a sub-millimeter level by using ultra-sound signals.The successful implementation of such an approach to brain imaging requires the following items:signals of sub-megahertz frequencies transmitting across the inside of skull,an accurate numerical wave equation solver simulating the wave propagation,and well-designed inversion schemes to reconstruct the physical parameters of targeted model based on the optimization theory.Here we propose an innovative modality of multiscale deconvolutional waveform inversion that improves ultrasound imaging resolution,by evaluating the similarity between synthetic data and observed data through using limited length Wiener filter.We implement the proposed approach to iteratively update the parametric models of the human brain.The quantitative imaging method paves the way for building the accurate acoustic brain model to diagnose associated diseases,in a potentially more portable,more dynamic and safer way than magnetic resonance imaging and x-ray computed tomography.
文摘The brain is protected from the entry of foreign substances by blood-brain barrier (BBB), but becomes a barrier while chemotherapy is needed for the brain diseases. Ultrasound with microbubbles (MBs) has been shown to noninvasively increase the permeability of the BBB in the normal tissue and brain tumor. The real mechanism for disruption is still unknown. Hemorrhage was usually found in the sonicated region of the brain. Thus, treatment safety is the primary concern when considering clinical application of BBB disruption induced by ultrasound in the presence of MBs. Here we investigate the effects of ultrasound on the permeability of BBB whether the MBs were administered. The data reveals that Evans blue (EB) accumulation was highest in the brain after sonication with MBs. However, the permeability of BBB also can be significantly increased by ultrasound alone. These results demonstrated that noninvasive disruption of BBB by ultrasound alone with no damage is possible.
文摘<strong>Objective</strong><span style="font-family:;" "=""><span style="font-family:Verdana;"><strong>: </strong>To evaluate the clinical value of transcranial color Doppler ultrasound (TCCD) in assessing cerebral function after cardiopulmonary resuscitation (CPR). </span><b><span style="font-family:Verdana;">Methods</span></b><span style="font-family:Verdana;">: A prospective study was conducted in 52 patients with cardiac arrest treated by CPR from January 2018 to January 2020, and its clinical data were analyzed</span></span><span style="font-family:Verdana;">. </span><span style="font-family:;" "=""><span style="font-family:Verdana;">According to classification of cerebral performance category (CPC), 31 cases (CPC grade 1 - 2) were selected in the good prognosis group and 21 cases (CPC grade 3 - 5) in the poor prognosis group. The cerebral blood flow was measured by transcranial Doppler ultrasound (TCCD) 24 h after CPR, and the differences were compared between the two groups in stroke index, diastolic blood flow velocity (Vd), systolic peak blood flow velocity (Vs) and mean peak blood flow velocity (Vm). The ROC curve of cerebral blood flow after CPR was drawn to predict the prognosis of brain function. </span><b><span style="font-family:Verdana;">Results</span></b><span style="font-family:Verdana;">: The data showed that the pulsatility index of middle cerebral artery of the poor prognosis group decreased within 24 h</span></span><span style="font-family:Verdana;">;</span><span style="font-family:Verdana;">the difference between the two groups was statistically significant (p < 0.05);the Vd, Vs, Vm increased in the good prognosis group</span><span style="font-family:Verdana;">;</span><span style="font-family:;" "=""><span style="font-family:Verdana;">the difference between the two groups was statistically significant (p < 0.05). The ROC curve of cerebral blood flow after CPR was drawn to predict the prognosis of brain function, and the results showed that the area under the curve and the optimal critical value of cerebral blood flow were 0.731 and 5.69. The sensitivity and specificity were 67.3% and 79.1% respectively. </span><b><span style="font-family:Verdana;">Conclusion</span></b><span style="font-family:Verdana;">: The cerebral blood flow increase in the early stage of successful CPR is positively correlated with the prognosis of cerebral functional resuscitation. Monitoring intracranial blood flow after CPR by TCCD has clinical value to evaluate prognosis of brain function.</span></span>
