RESUMO
Objective To compare three dimensional arterial spin labeling(3D-ASL) and dynamic susceptibility contrast-perfusion weighted imaging(DSC-PWI) in evaluating the cerebral hemodynamic of Moyamoya disease. Methods Approved by the institutional review board, 26 cases of Moyamoya patients who were diagnosed by DSA were enrolled. Diffusion weighted image, 3D-TOF-MRA, 3D-ASL, DSC-WPI, and T1WI were performed in 3.0 T MR scanner. ROI were positioned in the abnormal perfusion areas and the control area according to the arterial dominant territory to obtain quantitative parameters of perfusion. Perfusion parameters including cerebral blood flow(CBF) of ASL, cerebral blood flow(CBF), cerebral blood volume(CBV), mean transit time(MTT), and time to peak(TTP)of DSC-PWI , and relative parameters (ASL-rCBF, DSC-rCBF, DSC-rCBV, DSC-rMTT, DSC-rTTP) that the ratio of abnormal perfusion area and the control area were calculated. Meanwhile, the areas of the lower perfusion region of ASL and TTP images in the same slice were measured. Difference of the above-mentioned parameters and areas was processed by paired Student′ t test. Furthermore, correlation of relative values of perfusion parameters(ASL-rCBF, DSC-rCBF, DSC-rCBV, DSC-rMTT, and DSC-rTTP) was processed by Pearson correlation test. Results There were significant statistics differences between values of ASL-CBF, DSC-MTT, and DSC-TTP in abnormal perfusion [(28.18 ± 10.19)ml · 100 g-1 · min-1,(7.98 ± 2.22)s,(29.93 ± 3.95)s] and the control areas [(49.50 ± 11.37)ml · 100 g-1 · min-1,(6.07 ± 1.11)s,(27.34 ± 2.58)s] (t=-12.818, 4.193, 6.163, all P0.05). Furthermore, the Pearson correlation test showed significant linear dependence between ASL-rCBF(0.56±0.14)and DSC-rMTT(1.34± 0.42), and DSC-rTTP(1.09 ± 0.69)(r=-0.630,-0.748, P<0.01). Conclusions There is a correlation between 3D-ASL and DSC-PWI in assessing the magnitude and areas of the reduction of blood perfusion of Moyamoya patients. Moreover, the ASL technique possesses advantages of non-invasion use of the gadolinium contrast.
RESUMO
Objective To evaluate the application value of different MR sequences in cerebral developmental venous anomalies (DAVs),and to explore the relationship between DVAs and its associated lesions.Methods MRI findings in 38 patients of DAVs were analyzed retrospectively.Imaging performance and characteristics of DAVs and its associated lesions in different MR sequences were analyzed.Results In all of the 38 cases,3 cases were multiple DVAs without associated lesions,1 case was combined right lateral ventricle hemorhage,1 case was combined with multiple cavernous hemangioma,8 cases were single DVAs with solitary cavernous hemangioma,5 cases were combined with astrocytoma,1 case was combined with intracranial hematoma,and 19 cases were single DVAs with no comorbidity.DVAs in 16 cases showed strip or small patchy hypo-intensity lesions and 15 cases were not visible on T1WI;16 cases showed strip or small patchy hypo-intensity,5 cases showed strip or flocculent hypo-intensity and 10 cases could not seen on T2WI;19 cases showed patchy or strip hypo-intensity and 8 cases showed iso intensive signal on DWI;8 of the 10 cases who performed susceptibility weighted imaging (SWI) examination showed dendritic low signal,showing a typical caput medusae sign,2 cases showed no lesions on SWI;30 cases underwent 3D-T1WI enhanced scan showed clearly all lesions of DAVs,19 cases of them showed typical caput medusae sign and large draining veins.Conclusion Routine MR sequence can demonstrate part of the DVAs and associated peripheral lesions,DWI showed lesions of DAVs is superior to routine MR sequence,SWI and enhanced 3D-T1WI can accurately diagnose DVAs and show the venous drainage.
RESUMO
Objective To investigate the time course of cerebral infarction with diffusion kurtosis imaging-related parameters.Methods According to the time interval from symptom onset to MRI examination, 114 cases of cerebral infarction were divided into five groups:8 cases of hyperacute phase(less than 6 hours), 14 cases of acute(>6-24 h), 60 cases of early subacute(>24 h-7 d), 20 cases of late subacute(>7-14 d), and 12 cases of chronic phase ( >14 d-2 months).They underwent routine diffusion weighted imaging (DWI) and diffusion kurtosis imaging (DKI) scanning, and apparent diffusion coefficient ( ADC) and DKI-derived parameters were obtained from them.The derived diffusion parameters were compared among different phases in the patients , and the percent of changes in the infarcted regions were calculated.Paired t-test was used to compare the difference of each parameter between the infarcted region and contralateral normal region , and their correlation with time interval was tested using Pearson correlation analysis.Results Except for chronic phase , mean kurtosis ( MK) , axial kurtosis ( K∥) , radial kurtosis (K⊥)map showed uneven high signal in the infarcted regions , while mean diffusion(MD), axial diffusion(D∥), radial diffusion(D⊥) showed uniform low signal.MK values in the infarcted regions of hyperacute, acute, early subacute and late subacute phase (1.331 ±0.357,1.578 ±0.453,1.519 ±0.455, 1.403 ±0.275 ) increased significantly , compared with the contralateral normal mirror regions ( 0.850 ± 0.236,0.827 ±0.194,0.865 ±0.144,0.939 ±0.212) (t values were 5.242,6.907,12.416,5.629, respectively.P values were all less than 0.01 ).MK, K∥, K⊥ achieved a peak in the acute and early subacute phase , and showed more amplitude than the decrease of MD , D∥, D⊥.Then they gradually reduced, and tended to normalize.MK, MD, ADC had a significant correlation with the time onset of cerebral infarction ( r was 0.354, 0.747, 0.723, respectively, P values were all less than 0.05 ).Conclusion Diffusion kurtosis imaging can provide more diffusion information than conventional DWI , which can better reflect the microstructure changes in tissue.
