Comparative Study Of CT Examination And MRI Examination In Viral Encephalitis In Children

Objective: To compare the cranial CT and MRI imaging features of viralencephalitis in children, to explore the CT examination, MRI examination ofthe diagnostic value for viral encephalitis in children.Methods: The participants are44patients met the diagnosis of viralencephalitis in children who hospitalized in Hebei Medical University Medicalpediatric from October2010to October2011, including the diagnosis ofsevere viral encephalitis30cases divided into the group of severe encephalitis;and14cases of encephalitis are divided into general encephalitis group. Theimaging data of cranial CT and MRI examination and EEG data of childrenwith viral encephalitis were collected completely. CT scan uses the CTscanner of the Siemens Somaton Plus4, and Elex Elscint2400. Scanacquisition matrix is512×512, scan time is2s, and slice thickness and thelayer distance are5-10mm. MRI examination uses Etscint2.0T MRI scanmachine. The Tl Weighted like to adopt TRT00ms, TE18ms; T2-weightedimage use TR5500ms TE106ms, the FI AIR use TR6400ms, TEl600ms. EEGexamination use the no pen domestic16-channel EEG tracings, according tothe International10-20system electrode placement, time constant is0.3s, filteris50Hz sensitivity is1mm=5microvolt, it makes the single and bipolartracings, the recording time is30min. The main symptoms and signs in severeencephalitis group of children and ordinary encephalitis group of children, thepositive rates of abnormalities in CT scan and MRI examination, the positiverate of CT examination, MRI examination and EEG examination in differentperiods of the progression were contrasted and analyzed, the sub-positive rateof the degree of abnormalities in CT examination and MRI examination ofchildren in severe encephalitis group were contrasted and analyzed. The CTand MRI abnormalities of severe encephalitis group of children in the early course, the CT and MRI abnormalities of severe encephalitis group of childrenin the course of two weeks, the CT and EEG abnormalities of severeencephalitis group of children, and the MRI, EEG abnormalities of severeencephalitis group in children were contrasted and analyzed by usingSPSS13.0statistical software, describing the cases with count data andchoosing the method of matching tables from the X2test. Inspection levelalpha <0.05was considered statistically significant.Result: In the two weeks course of the disease of head CT and MRIexamination of severe encephalitis group and ordinary encephalitis group inchildren, there are22abnormal cases and8normal cases of CT examination insevere encephalitis group, the positive rate was73%. There are17cases ofmultiple lesions, accounting for56%. There are5cases of single lesion,accounting for17%. There are28abnormal cases and2normal cases of MRIexamination, the positive rate was93%, and21bilateral abnormal cases,accounting for70%,7unilateral abnormal cases, accounting for23%.Multiple, bilateral lesions compared with single unilateral lesions morecommon, lesions affected area is more common to the frontal lobe, temporallobe, parietal lobe, occipital lobe, thalamus, brain stem and other parts canalso be involved. MRI was significantly higher than the CT in severeencephalitis. There are2abnormal cases and12normal cases of CTexamination in ordinary encephalitis group, the positive rate was14%. Thereare0abnormal cases and14normal cases of MRI examination, the positiverate was0%. The CT examination of ordinary encephalitis showed only mildcerebral edema, positive rate is low, MRI revealed no abnormal findings.There are some positive rates of progression in the different periods of severeencephalitis group and ordinary encephalitis group of children in the CT scan,MRI examination and EEG examination. The positive rate of CT, MRI, andEEG in the initial of the duration in severe encephalitis group were25%,55%,60%, when the disease duration <1week, the positive rate of CT, MRI, theEEG's were45%,76%,80%, when the course of the disease at1-2weeks, thepositive rate of CT, MRI, and EEG were73%,93%,100%. The positive rate of CT, MRI, and EEG in the initial of the duration in ordinary encephalitisgroup were0%,0%,50%, when the disease duration <1week, the positiverate of CT, MRI, the EEG's were7%,0%,79%, when the course of the diseaseat1-2weeks, the positive rate of CT, MRI, and EEG were14%,0%,86%.Along with the progress, the sensitivity of CT, MRI and EEG can be increasedin the severe encephalitis group, the sensitivity of MRI and EEG are higherthan the sensitivity of CT. There are no positive findings in CT in ordinaryencephalitis group, along with the progress, the sensitivity of CT and EEG canbe increased, the sensitivity of EEG is higher than the sensitivity of CT.Because in the contrast between abnormal CT and abnormal MRI in the earlycourse of disease of the severe encephalitis group, X2=7.11, P <0.01, there aresignificant differences between the two, it has statistical significance.Abnormal findings in MRI inspection in the early course of disease of thesevere encephalitis group is more than in CT, in the contrast betweenabnormal CT and abnormal MRI in the two weeks course of disease of thesevere encephalitis group, X2=4.17, P <0.05, there are significant differencesbetween the two, it has statistical significance. Abnormal findings in MRIinspection is more than in CT. MRI of intracranial inflammatory changes inthe viral encephalitis, especially in the severe and early course is moresensitive than CT. Because in the contrast between CT abnormalities and EEGabnormalities in the severe encephalitis group, X2=6.125, P <0.025, therewere significant differences between the two, it has statistical significance.Abnormal findings in EEG inspection are more than in CT, EEG examinationis more sensitive than CT examination. There is a contrast on the degree of CTand MRI abnormalities in the severe encephalitis group. There are6mildlyabnormal cases in the abnormal performance of the CT examination,accounting for27%, there are12abnormal cases, accounting for55%, andthere are4severe abnormal cases, accounting for18%, the moderate andsevere abnormality rate are73%. There are5mildly abnormal cases in MRIabnormalities, accounting for18%,13moderately abnormal cases, accountingfor46%,10severe anomalies cases, accounting for36%, the moderate and severe abnormality rate are82%. Abnormal rate of moderate and severe MRIabnormalities is higher than CT abnormalities. MRI in the evaluation of severeviral encephalitis severity is more sensitive than CT. There are30cases of theEEG abnormalities and28cases of the MRI abnormalities in the severeencephalitis group. Because in the contrast between MRI abnormalities andEEG abnormalities X2=1, P>0.05, there are no significant differencesbetween the two, it has no statistical significance. The sensitivity of MRI is thesame as EEG.Conclusions:1. The clinical symptoms and signs of viral encephalitis inchildren, especially the severe viral encephalitis is lack of specificity, have thecharacteristic, the clinical diagnosis is difficulty, sometimes it may appearmisdiagnosed, the early and effective treatment of opportunistic were lost.2.CT examination, MRI examination and EEG examinations are noninvasiveexamination, likely to be accepted by the patients.3. CT examination isneither sensitive nor lack of specificity in the diagnosis of ordinaryencephalitis and severe encephalitis.4. EEG examination in the progression ofthe process of ordinary encephalitis and severe encephalitis disease is in highsensitivity but low specificity.5. MRI examination has a high sensitivity in theearly progression and severe viral encephalitis, and it can better assess theseverity and specificity.6. The application of MRI examination should bepromoted in clinical diagnose of severe viral encephalitis, to strive for theearly diagnosis and to give effective treatment measures to promote the effectof prognosis, early MRI examination needs to be emphasized.