ABSTRACT
Objective To prove whether it is availble to define the penumbra histopathologically and immunohistopathologically by observing the MRI T 2 imaging,cytoskeleton and neuron changing. Methods Seven cases of autopsy infarct brain with different ischemic time were studied in our program. By MRI T 2 imaging, the fixed brains were examined. Large section of whole brain, and small section of different parts,in and out of the infarct area, and the opposite hemisphere were observed. After observing the neuron, cytoskeleton, microglia, astrocyte, vessel, and also some cytokines by histological and immunohistochemical methods, we divide the ischemic and surrounding areas into four different parts as to seeing the different changes. Results In area 0, the neuron, gliocyte and vessel were all necrotic, eosinocytes developed, and cytoskeletons disappeared. In area 1, there were large number of dark neurons, shrinking cells with heavily destroyed, cytoskeleton, active microglia and inflammatory cells. In area 2, there were a few ischemic neurons , a few dark neurons, and normal neurons,and were also lots of active astrocyte and microglial. The proportion of area 2 was reduced sharply in two days. The ischemic proportion shown by MRI was smaller than that shown by large section of the whole brain. MRI T 2 imaging showed only the area 0 and area 1 with T 2 value increasing, and not showed the area 2 with normal T 2 value. In area 3, the cells were all in normal shape.However,the active microglia and astrocyte hyperplasia, together with the positive TGF ? and TNF? expression, existed in area 3 in all seven brains.Conclusions Area 0 is the infracted mature area, area 1 is the irreversible area, both of them are centers of the necrotic area. Combined with MRI, neuron and cytoskeleton changes, we conclude that area 2 is the possible reversible damage area, or the equal area of penumbra. Area 3 is the response area to ischemic damage, which in some authors’studies was called‘penumbra’.
ABSTRACT
The main composition of MRI system is introduced including magnet,gradient-RF system,cooling system,reconstruction system and operation system.According to the principle and functions of every component,the common troubles and the corresponding reasons of MRI system in using are analyzed,and the solutions are presented.[Chinese Medical Equipment Journal,2008,29(2):90,93]