CT perfusion imaging on the disturbance of regional cerebral microcirculation in a pre-infarction period : an experimental study
- VernacularTitle:脑梗死前期脑局部微循环障碍CT灌注成像的实验研究
- Author:
Peiyi GAO
;
Chenyang LIANG
;
Yan LIN
;
Fang YUAN
;
Ling HU
- Publication Type:Journal Article
- Keywords:
Cerebrovascular circulation;
Perfusion,regional;
Astrocytes;
Tomography, X-ray computed;
Animals,laboratry
- From:
Chinese Journal of Radiology
2001;0(08):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the CT perfusion imaging and the pathological features on the disturbance of regional cerebral microcirculation in a pre-infarction period, and to evaluate the relationship between the astrocytes and regional cerebral microcirculation. Methods Dynamic CT perfusion imaging of the models with regional cerebral hypoperfusion and astrocytic swelling in rats was performed to assess the presence or absence of the disturbance of regional cerebral microcirculation. Then, the histopathologic examination was made for both models, respectively. The ratios of side-to-side were measured at hypoperfusion areas in the models of regional cerebral ischemia. Results Regional hypoperfusion was revealed by regional cerebral blood flow (rCBF) and mean transit time (MTT) maps in the group of hypoperfusion for 6 hours. Regional cerebral blood volume (rCBV) and time-to-peak (TTP) maps were normal in that group. The ratios of rCBF, rCBV, MTT and TTP were 0 39-0 55, 0 92-1 00, 1 20-1 50 and 1 00-1 00 respectively. Astrocytic swelling pressing the capillary wall was obvious and subtle neuronal reversible degeneration was occasionally found. TTC stain was normal. In the tACPD group of astrocytic swelling, the abnormal hemodynamic regions on rCBF and MTT maps were found. The rCBV maps of 3 rats in the tACPD group showed the area of reduced rCBV. In 2 rats of tACPD group, the areas of delayed TTP were also found. The ratios of rCBF, rCBV, MTT and TTP were 0 25-0 44, 0 70-1 01, 1 20-2 00 and 1 02-1 45 respectively. TTC stain was negative. Electron microscope study revealed remarkable swelling of astrocytes, especially endfoot processes of astrocytes around capillaries. The abnormal hemodynamic region on rCBF and MTT maps matched with abnormal extent on histopathologic examination. The rCBV and TTP maps appeared normal. Conclusion The astrocytes can react in a way faster than the neurons in the pre-infarction period, viz. astrocytic swelling. The swelling of astrocytic foot, which pressed capillary vessel, induced the disturbance of regional cerebral microcirculation, and then aggravated hypoxic ischemic state in regional brain parenchyma. Perfusion CT and its parameters' analysis may play an increasing role to delineate the reversible hypoperfusion areas in pre-infarction period. Analyzing the relationship of rCBF and rCBV is very helpful to know the status of the capillary vessels in regional cerebral hypoperfusion area.
