The Study Of Cerebral Blood Flow By Xenon-CT In Patients With Chronic Cerebral Circulation Insufficiency

There can often be seen a number of old or pre-elderly patients clinically with repeated complaint of head-heavy, dizziness and other subjective symptoms, but no nerve damage and no signs of focal brain CT abnormalities in addition to fundus oculi arteriosclerosis. With this type of targeting, Japanese scholars put the concept "CCCI" forward, which means chronic cerebral circulation insufficiency, and developed criteria for its diagnosis. Prior to this, the domestic clinical workers have come to understand that the existence of patients in this category, but there is no name and diagnostic criteria of the disease in the classification of cerebrovascular disease in our country. It has been found that CCCI is not only the basis of invasion of TIA and development of brain arteriosclerotic infarctions, but also progressively causes white matter damage, Binswanger's disease, vascular dementia and other chronic cerebrovascular disease. Therefore, early diagnosis and intervention of CCCI has significant value in control and prevention of acute cerebral infarction, vascular dementia and other chronic cerebral ischemic disease. Due to the lack of specific diagnostic methods, in the past the diagnosis of CCCI mainly based on risk factors, clinical performance and TCD, but this is merely a rough intuitive clinical screening methods, lacking the fundamental basis of blood flow. It has been shown that XeCT can provide a dynamic quantification of the CBF, objectively reflect the degree of ischemia, find the abnormal changes earlier than the imaging examinations and provide a reliable basis for ultra-early diagnosis of cerebral ischemic. At present the application value of XeCT in diagnosis and treatment of CCCI is rare to be studied neither in our own country nor abroad. This study was designed to explore a new kind of inspection means, providing an objective basis for the early diagnosis and treatment evaluation of CCCI.In this study, we selected 22 cases with clinical symptoms passing the screening examination with TCD or MRI, those were initially considered as CCCI. We detected the cerebral blood flow using XeCT to make a definite diagnosis, and analyzed the clinical information. A 4-week treatment was given to the patients with a final diagnosis as CCCI using Yangxue Qingnao Granula, and its effect on the cerebral blood flow was observed by XeCT. We also discussed the relationship between cerebral blood flow and blood flow velocity in TCD as well as leukoaraiosis on MRI further.The results are as follows:①22 cases initially diagnosed as CCCI were detected for mean CBF of bilateral hemispheres and regional CBF in different positions by XeCT. The mCBF is decreased in 11 cases and normal in 11 others, and there shows significant difference in mCBF of bilateral hemispheres between the two groups (P<0.01). The rCBF in 20 cases have reduced to different extents, of which 8 cases are global cerebral ischemia while 12 are regional ischemia, while 2 cases show normal. Frontal and occipital rCBF decline can be seen most frequently, followed by parietal lobe. The CBF of hemisphere, cortical, white matter and basal ganglia in global cerebral ischemia group are much lower than normal group (P<0.01), while the CBF in regional ischemia group decrease compared with normal group, but not significant (P>0.05).②In the 20 patients with CCCI, headache and dizziness are the most principal symptoms, followed by head-heavy, distention and memory impairment. The most common risk factor is hypertension, followed by dyslipidemia. The scores of MMSE reduce in CCCI cases compared with health ones (P<0.05), of which 5 cases (25%) can be determined for MCI, while the scores of ADAS-cog are higher(P<0.05), and 11 cases (55%) show MCI, then ADAS-cog score has negatively linear correlation with the CBF of cortex and white matter (r=0.631, P<0.05).③Carotid ultrasound finds that 65% of CCCI patients show atherosclerosis, principally with atherosclerotic plaque, the location of which is mainly in the carotid bifuracation. The CBF of hemisphere, cortical, white matter and basal ganglia show no significant difference between carotid atherosclerosis group and normal group (P>0.05). TCD finds that 55% of CCCI patients show hemodynamic abnormality as slow blood flow velocity. The cortex CBF reduce in slow-velocity group compared with normal-velocity group (P<0.05), while the CBF of hemisphere, white matter and basal ganglia has no significant difference between two groups (P>0.05). Artery peak velocity has no linear correlation with the CBF of corresponding region (P>0.05), but in the blood-supply areas of MCA, peak velocity of MCA is slower in lower CBF areas than those with normal CBF (P<0.05).④MRI finds that 80% of the CCCI patients show leukoaraiosis in different extents, 9 of which are PVL combined with DWML and 7 are simple DWML, while other 4 cases have no significant white matter lesions. There is no significant difference of CBF between simple DWML group and group without LA (P>0.05). The mCBF in PVL+DWML group is lower than group without LA (P<0.05), and the CBF of white matter and basal ganglia in PVL+DWML group is lower than simple DWML group (P<0.05), while the CBF of hemisphere and cortex has no significant difference between two groups (P>0.05).⑤There are 13 cases of CCCI patients given treatment of Yangxue Qingnao particles, clinical symptoms in 92.3% of patients have improved to different extents, and ADAS-cog scores decrease after treatment compared with prior treatment (P<0.05). There is no significant difference of Artery peak velocity detected by TCD between post and prior treatment (P>0.05), and CBF of cortex and basal ganglia post treatment increase compared with prior treatment (P<0.05).XeCT perfusion imaging, as a safe, rapid method for detection of cerebral blood flow, can provide high accuracy, repeatable, quantitative measurement of the CBF value, sensitive of the CBF in deep brain tissue with advantages of convenient, fast and low-prices. First time we utilized XeCT for measurement of CBF to determine diagnosis of CCCI and has opened a new application of XeCT in the field of CCCI as a relatively new perfusion imaging technology. This study finds that detection of CBF by XeCT is not only able to show the global cerebral hypoperfusion, but also to discover local ischemia, and that the perfusion state of CCCI patients can not only be global cerebral ischemia, but also be local ischemia causing clinical symptoms as well. Through quantitative detection of CBF with XeCT, the change of CBF and the characteristic of cerebral perfusion in CCCI has been observed and analyzed, and further comparison of CBF and cognitive function, blood flow velocity in TCD, carotid atherosclerosis and leukoaraiosis on MRI has showed a close relation between the degree of cognitive dysfunction, slow blood flow velocity, white matter lesion and the decline of CBF, so that a new objective indicatrix has been provided for clinical evaluation of CCCI. We also apply XeCT into the evaluation of drug intervention, and it is confirmed that Yangxue Qingnao particles can increase CBF of CCCI patients, by comparing the CBF post and prior treatment. At present, clinical research about CBF change in CCCI is in serious shortage, and more testimony on evidence-based medicine is needed. The study of quantitative CBF by XeCT has provided an effective indicatrix for brain perfusion status, but there is no standardized test and analytical methods. Case number was relatively small in this study, thus large sample study and evidence-based medical research firms should be taken out further.In summary, it's believed that XeCT as a quantitative indicatrix of CBF, can provide an objective standard for early diagnosis of CCCI as well as an effective basis for the evaluation of treatment for CCCI. Mild cognitive impairment can be found in patients with CCCI patients and the severity of cognitive impairment is correlated with lower CBF. Slow blood flow velocity in patient with clinical symptoms especially slow-down flow of MCA highly prompts the existence of CCCI. Leukoaraiosis on MRI especially periventricular white matter lesion is related to lower CBF. Treatment of Yangxue Qingnao particles for CCCI patients leads to CBF increasing, symptoms relief and cognitive function improvement.