CT perfusion (CTP) has provide a novel approach for the diagnosis of ischemic cerebrovascular diseases. The evaluation indices include cerebral blood flow, cerebral blood volume, time to peak, and mean transmit time. These semi-quantitative indices used for evaluating cerebral blood perfusion have very important significance for the guidance of choosing the best treatment protocol and efficacy observation. CTP is mainly used in acute ischemic stroke to identify penumbra and infarct, as well as predicting hemorrhagic transformation in combination with other means and choosing thrombolytic candidates. In addition, CTP is also used to assess cerebrovascular reserve capacity in patients with chronic ischemic diseases and diagnose cerebral vasospasm in patients with subarachnoid hemorrhage and their efficacy evaluation.

The severity of ischemic brain injury was closely associated with the mortality and disability of stroke. How to limit ischemic brain injm-y to the greatest extent and promote the recovery of neurological function is one of the most concerned hotspots at present in the field of neuroscience. A large number of studies have shown that a variety of factors involve in the pathological process of ischemic brain injury, in which, the role of T lymphocyte-mediated immune inflammatory response in ischemic brain injury has received increasing attention. This article mainly reviews the role of T cells in ischemic brain injury.

There are a number of potassium channels on the cerebrovascular smooth muscle cell membrane, generally they are divided to 4 categories: voltage-gated potassium channels, calcium-activated potassium channels, inward rectifier potassium channels and ATP sensitive potassium channels. They can modulate cerebrovascular tone, so as to impact on cerebral blood flow to adapt to different situations of physiological pathology. The structure and function of potassium channels change after subarachnoid hemorrhage, These changes may be associated with the occurrence and development of cerebral vasospasm. The application of potassium channel opener may relax cerebrovascular smooth muscle and attenuate cerebral vasospasm.

Since 1990, the microembolic monitoring technology has been widely used in clinical practice and some progress has been made. This article reviews the new advances achieved in recent years, the problems facing and the direction of new development for microembolic monitoring in clinical research.

Carotid endarterectomy (CEA) can effectively treat symptomatic carotid stenosis, however, perioperative stroke is the most important complication of CEA. The microemboli generated before and after the operation are the most important reason for causing perioperative stroke. In addition, the hypoperfusion and postoperative hyperperfusion syndrome caused by intraoperative clipping of carotid artery, as well as carotid restenosis or occlusion after CEA are all the causes of perioperative stroke. As a non-invasive, real-time monitoring tool, transcranial Doppler (TCD) can be widely used in intraoperative monitoring of CEA, It is able to detect a variety of perioperative blood flow changes and the production of microemboli, and thus effectively predicts the occurrence of perioperative stroke, and decreases the risks of perioperative stroke.

Objective To investigate the expression of neuronal extracellular signal-regulated kinase 1/2 (ERK1/2) and its significance after cerebral isehemia reperfusion in diabetic rats. Methods Seventy-two healthy adult SD rats were randomly divided into sham-operation, normal glucose with cerebral ischemia and diabetes with cerebral ischemia groups. Each group was redivided into ischemia 15 minutes and reperfusion 1, 3 and 6 h subgroups according to the different time points of ischemia reperfusion (n = 6 in each subgroup). Streptozocin was used to induce diabetes, and a global cerebral ischemia model of diabetic rat was established by the bilateral vascular occlusion combining with bloodletting, TUNEL and immunohistochemistry were used to observe neuronal apoptosis and the expression of the phosphorylation of ERK1/2 in hippocampal CA4 region. Results The incidences of neuronal apoptosis in hippocampal CA4 region for ischemia 15 minutes and reperfusion 1, 3 and 6 h in the diabetes with cerebral ischemia group were significantly higher than those in the normal glucose with cerebral ischemia group (P < 0. 05); the expressions of the phosphorylation of ERK1/2 at all time points in the diabetes with cerebral ischemia group were higher, and reperfusion 1 and 3 h were significantly higher than those in the normal glucose with cerebral ischemia group (P < 0.01). Conclusions ERK1/2 might involved in the mechanism of neuronal injury after diabetes aggravating cerebral ischemia-reperfusion.

Ischemic cerebrovascular disease may result in severe neurological deficits, and even death. Rho kinase is an important downstream substrate of Rho protein. It involves in multiple biological effects, including vascular smooth muscle contraction, cell migration, inflammatory cell infiltration and vascular endothelial dysfunction. It plays important roles in the processes of the occurrence, development and expansion of infarct volume in ischemic cerebrovascular disease. Rho kinase inhibitor can effectively relax vascular spasm, reduce local inflammatory response, protect endothelial function, increase blood flow in ischemic region, reduce infarct volume, and improve neurological function.

Cerebral vasospasm is the main reasons of cerebral infarction and delayed ischemic neurological deficit in patients with spontaneous subarachnoid hemorrhage. At present, the research of cerebral vasospasm is relatively focused on the spasmogens in bloody cerebro-spinal fluid. This article reviews the mechanisms of cerebral vasospasm induced by the major spasmogens in the bloody cerebrospinal fluid after subarachnoid hemorrhage.

Chronic cerebral hypoperfusion is a common pathological state. Cognitive impairment is its main manifestation in early stage, and it will eventually result in persistent or progressive cognitive impairment and neurological deficits. Chronic cerebral hypoperfusion caused neuronal damage, synapse abnormity, energy impairment and the function defects of central cholinergic system and monoaminergic system are its pathophysiological mechanisms resulting in cognitive impairment.

Substantia nigra is the largest nuclei in midbrain, which is divided into a compact part and a reticular part. Recent studies have shown that the changes of iron content in reticular part of substantia nigra results in the changes of substantia nigra echogenicity. The substantia nigra detected by transcranial Doppler, according to its echo changes, may provide help for the susceptibility of Parkinson's disease, latency and early diagnosis, as well as for the differential diagnosis of multiple system atrophy and vascular parkinsonism.