Application Of Diffusion Tensor Imaging And Magnetic Resonance Spectroscopy In Severe Traumatic Brain Injury

Part I Evaluation of diffusion tensor imaging (DTI) and magneticresonance spectroscopy (MRS) in normal adult brainPurpose:Using MRS to evaluate the brain metabolite of volunteers,and elucidate thedifference of neurometabolite markers in the normal adult brain. Next, using DTItechnology to investigate the FA value in the different part of the brain．Material andmethods:58healthy adult volunteers (29men,29women；age range:20-59years；mean age38years) were studied using MRS imaging and diffusion tensor imaging techniques．Thedifference of neurometabolite markers among parcnchyma of hemisphere,gender and thegray／white matter by the relative quantification and pseudocolor images of NAA,Cho,Cr were compared．The FA values were measured in the different parts oft he brain．TheROIs were external capsule,anterior limb of the internal capsule,posterior limb of theinternal capsule,genu of corpus callosum,splenium of corpus callosum, semioval center,,thalamus and cerebrospinal fluid．Results:No significant differences can be founded in theneurometabolite markers between right and left parench of frontal lobe in normal adult,and there no neurometabolite markers difference between gender in normal adults．Thedifference between gray and white matter in the front lobe is significant in normaladult．NAA／Cr decline and Cho／Cr increase was found with advancing age．Their wassignificant difference in FA between male and female or between the fight and lefthemisphere．There was significant difference in FA between the ROls of this study．TheFA value of the splenium of the corpus callosmn is highest．And external capsule is thelowest in the white matter of the brain．FA value decline was found with advancingage．Conclusion:By spectrum, relative quantification can be used to evaluate the difference of brain metabolite．The neurometabolite markers is influenced by age, andneurometabolite markers between white matter and gray matter is different,and thesefactors should be considered when studying MRSI of the brain．FA value can be used toquantitative anisotropy of the different part of the brain．There was a tennuous FA valuereduction with increasing age． Part ⅡApplications of DTI and1H-MRS in severe brain injuryPurpose:To investigate the characteristic of DTI and1H-MRS in patients sufferedfrom severe traumatic brain injury,and the correlation between neuromctabolitc markers ofthe patients and their GCS．Material and methods:We reported MRI and proton magneticresonance spectroscopy studies of72head-injured patients performed once the patientswere clinically stable (mean9.2days after injury,range1-16days)．Proton magneticresonance spectra acquired from white matter of hibateral frontal lobe that on conventionalMRI peared normal using MRSl with3.0T．58volunteer as control were studied at thesame time．Results:The brain Nacetylaspartate／creatine ratio was reduced and thecholine／creatine ratio was increased compared with controls．When the severity of theinjury was assessed using the Glasgow coma scale,the increase in the choline／creatineratio was significant even in the moderate and severe injured group．Furthermore,therewas a significant correlation between the severity of STBI and the N-acetylaspartate／choline ratio． Conclusion: We concluded that there is an early reduction inN-acetylaspartate and all increase in choline compounds in normal·appearing white matterwhich correlate with head injury severity,and that this may provide a useful tool that cantell the severity of the brain injury in patients with traumatic brain injury． Part Ⅲ1H-Magnetic Resonance Spectroscopy can predict comaduration in patients following severe traumatic brain injuryPurpose:To investigate whether the evaluation and prediction of outcome in the earlyphase after severe TBI is possible by means of single-voxel proton Magnetic ResonanceSpectroscopy (1H-MRS). Materials and Methods: The MRS were acquired from theposterior part of normal-appearing frontal lobes containing predominantly white matter in72patients following severe TBI at an early time point (mean9.5days). Results:1H-MRS indicated that the ratios of N-acetylaspartate (NAA)/Choline (Cho) and NAA/Creatine (Cr) decreased while that of Cho/Cr increased compared with those for the controlgroup. In severe TBI patients,NAA/Cr, NAA/Cho, and Cho/Cr ratios were significantlycorrelated with changes in initial Glasgow Coma Score (GCS()p=0.004, r=0.439；p=0.018,r=0.364；p=0.004, r=-0.762, respectively), and with clinical outcome of the patients,assessed by using Glasgow Outcome Scores (GOS) levels (p=0.006, r=0.414；p=0.007, r=0.412；p=0.016, r=-0.775, respectively). An equation (lg (y)=1.027+0.004595(age)-0.0755(GCS)-0.0987(conditions of pupils)+0.04518(number of foci)+0.527/(NAA/Cr)) including clinical and spectroscopic variables, which can predict coma duration withfairly accurate, was also obtained. Conclusions:1H-MRS may be a novel method ofassessing brain function, estimating coma duration, and predicting outcome in severe TBI.