| ObjectiveTo discuss the diagnostic and the grading value of Diffusion Tensor Imaging and Arterial Spin Labeling in Hypoxic Ischemic Encephalopathy, and to assessment the consistency of these two sequences’ grading and clinical grading.Material and MethodIn this committee-approved study, after giving written informed consent, thirty subjects were retrospectively between June 2011 and December 2014. According to the standard of Chinese medical association made in 2005, Sixteen full-term neonates which clinically diagnosed as HIE were selected as a HIE group (10 boys,6 girls, gestational age,37-42 weeks, birth age,2-28 day; mean,13.5 day). The reasons of HIE mainly include intrauterine distress, amniotic fluid aspiration, dystocia, mothers with gestational hypertension during pregnancy and so on, which cause the newborn who was born with the symptom such as purple or convulsions. Fourteen full-term neonates without any nervous system disease were chosen as a normal group(8 boys, 6 girls, gestational age,37-42 weeks, birth age,5-15 day; mean,8.7 day).All neonates were examined in the supine position with the Magnetom Skyra 3.0T MR scanner (Siemens Healthcare, Erlangen, Germany). A standard high definition receive-only multi-element (eight-elements) surface head coil was used. All neonates in HIE group and normal group were underwent axial routine MRI (T1WI, T2WI, T2-FLAIR, DWI) and MRS scan. The parameters of MRS were: TR/TE=1700ms/135ms, slice thickness=5.0mm, slice gap=1.0mm. The parameters ratios of MRS were Cho/Cr, NAA/Cr, Lac/Cr.According to routine MRI, all neonates were divided into experimental group and control group, and performed DTI and ASL scan, the parameters of DTI were: TR/TE=11700ms/95ms, matrix size=220×220, FOV=260mm×260mm, the parameters of ASL were:TR/TE=5000ms/36.3ms, matrix size=190×190, FOV=260mm×260mm. DTI and ASL were processed by Siemens workstation. ROIs were manually drawn by two radiologists with more than five years’experience in image processing. Fractional anisotropy (FA), relative anisotropy (RA) and volume ratio (VR) were measured in the map of DTI, relative cerebral blood flow (rCBF) were measured in the map of ASL. The signal of the ROIs of both the control and the experimental group were measured on bilateral basal ganglia, thalamus, frontal white matter and parietal white matter for three times, the mean value were calculated and compared between groups.Results1. the results of DTI:The fractional anisotropy (FA) and relative anisotropy (RA) value of ROIs were lower in experimental group than in control group, the volume ratio (VR) value of ROIs were higher in experimental group than that in control group. With the increase of HIE severity, the FA value of different degree HIE of ROIs was reduce. By chi-square test, the HIE detection rate of the FA value of the basal ganglia was consistent with clinic.2. the results of ASLThe relative cerebral blood flow (rCBF) value of the basal ganglia was higher in experimental group than that in control group, and there was no significant difference in the rCBF value of the white matter. With the increase of HIE severity, the rCBF value of different degree HIE of the basal ganglia and thalamus increased. By chi-square test, the HIE detection rate of the rCBF value of the basal ganglia and thalamus were consistent with clinic.Conclusion1. DTI and ASL are noninvasive techniques in the detection of HIE and in the judgment of its severity, which have strong practicality and favorable clinical prospects.2. When FA value of the basal ganglia is lower than 0.52 or the rCBF value of the basal ganglia and thalamus is higher than 671.07, they have e higher diagnostic value for HIE in the clinical.3. Combined with routine MRI and MRS, DTI and ASL can assess and grade HIE better and be beneficial for the clinical treatment and outcome prediction. |
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