Applcation Study Of The Diffusion Tensor Imaging In Patients With Dlayed Encephalopathy After Acute Carbon Monoxide Poisoning

1. ObjectiveThe image quality of magnetic resonance diffusion tensor imaging were influenced by many factors. The key factors was diffusion sensitive factor (b-value), number of diffusion gradient directions(NDGD), slice/interval thickness. How in a relatively short period of time to obtain high quality image of MR diffusion tensor imaging were very important for clinical diagnosis and scientific research. The main objective of this part was to search the best scanning parameter for MR diffusion tensor imaging of brain in the clinical study.2. Materials andMethods30 healthy adult volunteers (19 men,11 women; age range 20-65years; mean age 40.3 years) were studied by MR Diffusion tensor imaging. The volunteers were randomly divided into three groups, which respectively was the NDGD group,b value group and slic/interval thickness group. The NDGD group:variable parameter was the NDGD, which respectively was 6 direction,15 direction,25 direction;invariable parameter were b value(1000s/mm2)and slice/interval thickness(5/0mm).The b value group:variable parameter was b value,which respectively was 500 s/mm2,1000 s/mm2,3000s/mm2;invariable parameter were the NDGD (15 direction)and slice/interval thickness(5/0mm).The slice/interval thickness group:variable parameter was slice/interval thickness,which respectively was 8/2mm,5/0mm,3/0mm,invariable parameter were b value(1000s/mm2)and the NDGD(15direction). Two radiology experts gave a score to every imaging with double blind methods,then compared the image quality.3 ResultsDifferent parameters and different impaction on the quality of image of the FA and DEC map. The quality of image with 25 NDGD was better than those with 15 NDGD (2.83±0.38 vs 2.67±0.51, p<0.05) and 6NDGD (2.83±0.38 vs 2.17±0.43, p<0.05).The quality of image with b value of 1000 s/mm2 was equal to that with b value of 500 s/mm2 (2.67±0.49 vs 2.50±0.56, p>0.05) and better than that with b value of 3000 s/mm2(2.67±0.49 vs 2.06±0.55, p<0.05).The quality of image with 8/2 mm of slice/interval thickness was equal to that with 5/0 mm(2.67±0.54 vs 2.61±0.42, p>0.05) and better than that with 3/0mm of slice/interval thickness (2.67±0.54 vs 1.94±0.35, p<0.05).3. ConclusionScanning with 25 NDGD, b value of 1000s/mm2 and 5/0mm of sice/interval thickness is the best scanning parameter for MR diffusion tensor imaging of brain.Part II Applcation Study of the Diffusion Tensor Imaging in Patients with Dlayed Encephalopathy after Acute Carbon Monoxide Poisoning1. ObjectiveDelayed encephalopathy after acute carbon monoxide poisoning (DEACMP) is a serious complication of carbon monoxide intoxication. However its pathophysiological mechanisms have yet to be clarified. Magnetic resonance imaging(MRI) can detect abnormalities lesions of brain in patients with DEACMP and show significant clinical value. Now, magnetic resonance diffusion tensor imaging (DTI) have been applicated for this disease. The main objective of this part is to analyze the diagnostic value of diffusion tensor imaging in patients with dlayed encephalopathy after acute carbon monoxide poisoning at 3T Magnaton. 2. Materials and methods35 patients with dlayed encephalopathy after acute carbon monoxide poisoning weres confirmed by clinic and 35 age-match-healthy patients were examined by conventional MRI and DTI. According to the clinical therapeutic effect and follow-up results, the DEACMP patients were divided into good and poor prognosis groups.The average diffusion coefficient(ADC)map, fractional anisotropy(FA)map was acquired through image post processing technique. The ADC value and FA value of white matter and gray matter in patients with DEACMP group and control group were measured by region of interest (ROI) with the same standard (Fig 1-6) and the results were statistically analyzed.by SPSS 18.0.3.Result3.1 MRI and DTI imaging findings of brain in patients with DEACMP (Fig7-11)MRI and DTI findings in patients with DEACMP including:?cerebral white matter involvement in 32 cases, the lesions mainly involved peri ventricular white matter and the centrum semiovale, showing hopointensity or isopointensity on T1WI and FA map, hperintnsity onT2WI, FALIR and ios map, hopointensity on ADC and FAmap,?neural nuclei involvement in 21 cases, the lesions mainly involved globus pallidus, showing hopointensity on T1WI and FA map, hperintnsity on T2WI and FALIR, isopointensity or hpointnsity on iso map, hperintnsity or isopointensity on ADC map.?ormal signal intensity in 3 cases.3.2 The ADC values and FA values comparison of white matter of barin between DEACMP group and control group (chartl?chart2)The average ADC and FA value of white matter in DEACMP group were obviously lower than that of normal control group and had significant difference (p <0.05). In DEACMP group, the ADC and FA values of different regions in white matter were also different. The ADC values of the centrum semiovale and periventricular white matter were reduced obviously (centrum semiovale:3.87±0.42 vs 6.82±0.35, p=0.00; periventricular white matter:4.48±0.51 vs 7.47±0.39, p=0.00), and The FA values of the centrum semiovale and periventricular white matter were also reduced obviously (centrum semiovale:0.32±0.05 vs 0.51±0.04, p=0.00; periventricular white matter:042±0.01 vs 0.63±0.03, p=0.00)3.3 The ADC values and FA values comparison of basal ganglia of barin between DEACMP group and control group (chart3?chart4)In DEACMP group, the ADC and FA values of different regions in white matter were also different.The average ADC of globus pallidus, putamen, caudate nucleus, and substantial nigra and the average ADC of basal ganglias were significantly lower than that of normal control group and had significant difference (p<0.05). The ADC value of globus pallidus increased and had significant difference (13.2±0.29 vs 6.26±0.60, p<0.01).The ADC value of dorsal thalamus and red nucleus also increased but had no significant difference (p>0.05). The FA value of globus pallidus reduced obviously and had significant difference (0.19±0.07 vs 0.36±0.05, p<0.01),.,3.4 The clinical data, the ADC values and FA values of DEACMP comparison between good and poor prognosis group (chart 5?chart 6)Compared with good prognosis group, the poor prognosis group had older age, longer unconsciousness time, short fake-cure stage, and high incidence of fundament diseases (p<0.05).The ADC and FA value of white matter of DEACMP in poor prognosis group were significantly lower than that of good prognosis group (ADC:4.87±0.52 vs 6.20±0.46, p<0.05; FA:0.41±0.05 vs 0.53±0.03, p <0.05). The ADC values of gray matter of DEACMP in poor prognosis group were significantly high than that of good prognosis group (9.45±0.32 vs 7.31±0.43, p <0.05). The FA values of DEACMP in poor prognosis group were significantly lower than that of good prognosis group (0.17±0.06 vs 0.28±0.04, p<0.05).4.ConclusionThe DTI technology can accurately reflect the microstructure abnormalities of white matter and gray matter of brain in patients with DEACMP. The ADC values and FA values not only can accurately reflect different stages pathophysiological microcosmic structure changes, but also quantitative brain damage. which may provide some complementally informations and clinical diagnostic value for disease development, testing treatment effect, estimating prognosis and guide clinical treatment.