Value Of Functional Magnetic Resonance Imaging For Diagnosis Of Autoimmune Encephalitis

Objective: The present study intends to explore the role and value of functional magnetic resonance imaging in early diagnosis of AE through MRI diffusion weighted images(DWI), arterial spin labeling perfusion imaging (ASL) and proton magnetic resonance spectroscopy (1H-MRS), and provide basis for early diagnosis of AE.Methods: We selected 17 AE patients , 19 virus encephalitis patients and 19 subacute cerebral infarction patients in our study. All the patients were submitted to our hospital during march 2015 to march 2017. All patients underwent routine MR scan and enhancement, DWI, ASL and 1H-MRS before treatment. Analyze the relative apparent diffusion coefficient (rADC) values of DWI, the relative regional cerebral blood flow(rCBF) values of ASL and NAA/Cr, Cho/Cr, Cho/NAA values of 1H-MRS in each group,values of these parameters were compared and analyzed by statistical software.Exploring the differences between AE, viral encephalitis and subacute cerebral infarction,then evaluating the value of each examination in early diagnosis of AE.Results: (1) DWI: The rADC (1.439±0.272) of AE was significantly higher than that of viral encephalitis (0.492±0.102) and subacute cerebral infarction (0.531±0.085),P<0.01,the difference was statistically significant. The rADC of viral encephalitis was lower than that of subacute cerebral infarction, P<0.05, the difference was't statistically significant.(2) ASL: The rrCBF value of AE (1.875±0.628) was lower than that of viral encephalitis(2.163±0.910),P>0.05, no significant statistical significance. The rrCBF values of AE and viral encephalitis were higher than that of subacute cerebral infarction (0.478±0.213),P<0.01, the difference was statistically significant.(3) 1H-MRS:? The Cho/NAA value of AE (0.843±0.179) had statistical differences compared with viral encephalitis (1.529±0.215) and subacute cerebral infarction(1.385±0.293), P<0.05. These was no statistical differences between viral encephalitis and subacute cerebral infarction,P>0.05.? The Cho/Cr value of AE(1.245±0.203) had statistical differences compared with viral encephalitis( 1.554±0.274) and subacute cerebral infarction(1.422±0.213), P<0.05. These was no statistical differences between viral encephalitis and subacute cerebral infarction, P>0.05.? The NAA/Cr value of AE(1.298±0.185) was higher than that of viral encephalitis (1.159±0.113) and subacute cerebral infarction (1.097±0.187), P<0.05, the difference was statistically significant. Viral encephalitis NAA/Cr was slightly higher than that of subacute cerebral infarction group,P>0.05, the difference was not statistically significant. ?There was no obvious Lac in AE group, but it was observed in the other two groups and most common in subacute cerebral infarction group.Conclusion: (1) The rADC of DWI may have differential value between AE and viral encephalitis, it may also have differential value between AE and subacute cerebral infarction. (2) The rrCBF of ASL may lack of differential value between AE and viral encephalitis, but it still need further study of expanded size of the sample. rrCBF may have differential value between AE and subacute cerebral infarction. (3) The Cho/NAA of 1H-MRS may lack of differential value among AE with viral encephalitis and subacute cerebral infarction. The Cho/Cr of 1H-MRS may lack of differential value among AE with viral encephalitis and subacute cerebral infarction. The NAA/Cr of 1H-MRS may have differential value among AE with viral encephalitis and subacute cerebral infarction.Functional magnetic resonance imaging is of importance in the early diagnosis of AE.