Application Of MRP And MRS In Diagnosis Of Chronic Cerebral Ischemia

Chronic cerebral ischemia is caused by arteriosclerosis and other reasons which lead to the overall level reduction of the cerebral blood supply, or inbalance between blood supply and demand. The main clinical manifestation includes dizziness, headache, insomnia, and persistent or progressive cognitive impairment. The chronic cerebral ischemia can be sorted to chronic cerebral circulation insufficiency(CCCI), leukoaraiosis caused by chronic cerebral ischemia (subcortical atherosclerotic encephalopathy)and cerebral atrophy .It is the pathological basis of vascular dementia, Alzheimer disease and many other diseases.With the increase of the incidence of chronic cerebral ischemia and its long pre-clinical time to intervention, early diagnosis of this disease is important. But now the diagnosis of this disease is difficult. There is no reliable and specific method. The diagnosis mainly depends on the risk factors, clinical manifestation and TCD. Patients mainly complain of dizziness, headache, dizziness, memory loss, insomnia, drowsiness, with no neurological signs of local damage , TCD shows the cranial flow velocity of the large vessels decreases, and neck vascular ultrasound shows multiple atherosclerotic changes. Patients who meet the above critera can be initially diagnosed with chronic cerebral ischemia clinically. But this is only a crude method of clinical selection, because of the lack of cerebral blood flow and metabolism evidence. MRP and MRS may provide objective evidence of cerebral blood flow and metabolism and can be widely used in clinical practice .In this paper, we studied the combined application of MRP and MRS in the diagnosis of chronic cerebral ischemia for the first time based on the recent.Methods: Fifteen patients were collected including nine initially diagnosed with chronic cerebral ischemia and six age-matched volunteers. Each of the subjects were applied Trio tim Siemens 3.0 T superconducting whole body MRI scanner, with the standard head coil, and scan covered covering the whole brain. Measured and calculate the CBF, CBV, MTT, TTP. Lac and the rate of the NAA/ Cr,Cho/ Cr in the region around the horn lateral ventricle and centrum semiovale.Results:①the lateral ventricle level:CBF was lower in case group than the control group and there was significant difference between the two groups; CBV was larger in case group than the control group and there was no significant difference between the two groups; MTT and TTP in case group were longer than the control groups, and there were no significant difference between the two groups②centrum semiovale level : CBF and CBV were higher in case group than the control group, and there were significant difference between the two groups; MTT and TTP in case group were longer than the control group and there were no significant difference between the two groups.③centrum semiovale level of white matter: CBF and CBV were lower in case group than the control group and there were significant difference between the two groups; MTT and TTP in case group were longer than the control group and there were no significant difference between the two groups.④the result of MRS in the lateral ventricle level: The ratio of NAA / Cr was lower in case group than the control group ,and there was no significant difference between the two groups; The ratio of Cho / Cr was higher in case group than the control group , and there was significant difference between the two groups ; The content of lacid acid is higher in case group than the control group, and there is no significant difference between the two groups.⑤the result of MRS in the centrum semiovale level: The ratio of NAA / Cr was lower in case group than the control group, and there was no significant difference between the two groups; The ratio of Cho / Cr was higher in case group than the control group, and there was significant difference between the two groups; The content of lacid acid was higher in case group than the control group, and there was significant difference between the two groups.Conclusions: (1) MRP can detect the hypoperfusion status in patients with chronic cerebral ischemic; (2) MRS can detect the disorder of energy metabolism in the chronic cerebral ischemia, and shows that white matter nerve fibers are damaged more seriously than nurons;(3) Some of the parameters such as CBF,TTP,MTT in MRP and Cho / Cr in MRS can provide objective evidence for the diagnosis of chronic cerebral ischemia.