Radiomics based on three-dimensional high-resolution MR vessel wall imaging for identification of culprit plaques in symptomatic patients with middle cerebral artery atherosclerosis / 中华放射学杂志

Objective:To investigate the value of radiomics based on three-dimensional high resolution MR vessel wall imaging (3D HRMR-VWI) for identifying culprit plaques in symptomatic patients with middle cerebral atherosclerosis.Methods:The clinical and imaging features of 117 patients (139 middle cerebral artery plaques) with cerebrovascular diseases in Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology from October 2018 to October 2020 were respectively reviewed. Stratified random sampling was used to divide 139 plaques into training set (97 plaques) and validation set (42 plaque) at the ratio of 7∶3. The plaques were divided into 69 culprit plaques and 70 non-culprit plaques based on plaque MR features and clinical symptoms. The clinical and imaging characteristics of culprit plaques and non-culprit plaques were compared by independent sample t-test, Mann-Whitney U test and χ 2 test, and factors with significant difference between two groups in univariate analysis were further analyzed by multivariate logistic regression to find out the independent predictors of culprit plaques. Radiomics features were extracted, screened and radiomics model was constructed using pre-and post-contrast 3D HRMR-VWI based on the training set. The combined model was constructed by combining the independent predictors and radiomics model. Receiver operating characteristic curve and area under curve (AUC) were used to evaluate the efficacy of each model, and DeLong test was used to compare the efficacy of different models. Results:Significant difference was found in intraplaque hemorrhage, lumen area of stenosis, stenosis diameter, stenosis rate, plaque burden and enhancement rate between culprit and non-culprit plaques (all P<0.05). Multivariate logistic regression analysis confirmed that only intraplaque hemorrhage was the independent predictor for culprit plaques (OR=7.045,95%CI 1.402-35.397, P=0.018). In the validation set, the AUC of the pre-contrast 3D HRMR-VWI model was lower than that of the post-contrast 3D HRMR-VWI model ( Z=-2.01, P=0.044). The AUC of pre+post-contrast 3D HRMR-VWI model was not significantly different from that of post-contrast 3D HRMR-VWI model ( Z=0.79, P=0.427). The AUC showed no significant difference between combined model and pre+post-contrast 3D HRMR-VWI model ( Z=-0.59, P>0.05). The combined model showed the best performance in predicting culprit plaques of middle cerebral artery (AUC=0.939), with the sensitivity, specificity and accuracy of 95.24%, 76.19% and 85.71%. Conclusion:Radiomics based on 3D HRMR-VWI has potential values in identifying culprit plaques in symptomatic patients with middle cerebral atherosclerosis.

Feasibility of a Clinical-Radiomics Model to Predict the Outcomes of Acute Ischemic Stroke

Objective@#To develop a model incorporating radiomic features and clinical factors to accurately predict acute ischemic stroke (AIS) outcomes. @*Materials and Methods@#Data from 522 AIS patients (382 male [73.2%]; mean age ± standard deviation, 58.9 ± 11.5 years) were randomly divided into the training (n = 311) and validation cohorts (n = 211). According to the modified Rankin Scale (mRS) at 6 months after hospital discharge, prognosis was dichotomized into good (mRS ≤ 2) and poor (mRS > 2); 1310 radiomics features were extracted from diffusion-weighted imaging and apparent diffusion coefficient maps. The minimum redundancy maximum relevance algorithm and the least absolute shrinkage and selection operator logistic regression method were implemented to select the features and establish a radiomics model. Univariable and multivariable logistic regression analyses were performed to identify the clinical factors and construct a clinical model. Ultimately, a multivariable logistic regression analysis incorporating independent clinical factors and radiomics score was implemented to establish the final combined prediction model using a backward step-down selection procedure, and a clinical-radiomics nomogram was developed. The models were evaluated using calibration, receiver operating characteristic (ROC), and decision curve analyses. @*Results@#Age, sex, stroke history, diabetes, baseline mRS, baseline National Institutes of Health Stroke Scale score, and radiomics score were independent predictors of AIS outcomes. The area under the ROC curve of the clinical-radiomics model was 0.868 (95% confidence interval, 0.825–0.910) in the training cohort and 0.890 (0.844–0.936) in the validation cohort, which was significantly larger than that of the clinical or radiomics models. The clinical radiomics nomogram was well calibrated (p > 0.05). The decision curve analysis indicated its clinical usefulness. @*Conclusion@#The clinical-radiomics model outperformed individual clinical or radiomics models and achieved satisfactory performance in predicting AIS outcomes.

Cortical and Subcortical Grey Matter Abnormalities in White Matter Hyperintensities and Subsequent Cognitive Impairment / 神经科学通报·英文版

Grey matter (GM) alterations may contribute to cognitive decline in individuals with white matter hyperintensities (WMH) but no consensus has yet emerged. Here, we investigated cortical thickness and grey matter volume in 23 WMH patients with mild cognitive impairment (WMH-MCI), 43 WMH patients without cognitive impairment, and 55 healthy controls. Both WMH groups showed GM atrophy in the bilateral thalamus, fronto-insular cortices, and several parietal-temporal regions, and the WMH-MCI group showed more extensive and severe GM atrophy. The GM atrophy in the thalamus and fronto-insular cortices was associated with cognitive decline in the WMH-MCI patients and may mediate the relationship between WMH and cognition in WMH patients. Furthermore, the main results were well replicated in an independent dataset from the Alzheimer's Disease Neuroimaging Initiative database and in other control analyses. These comprehensive results provide robust evidence of specific GM alterations underlying WMH and subsequent cognitive impairment.

Quantitative Analysis of Parotid Gland Secretion Function in Sjögren's Syndrome Patients with Dynamic Magnetic Resonance Sialography

OBJECTIVE: To evaluate the secretory function of parotid glands by dynamic magnetic resonance (MR) sialography and determine the clinical performance of this technique in diagnosing and evaluating Sjögren's syndrome (SS) patients. MATERIALS AND METHODS: This study enrolled 29 healthy volunteers (25 women and 4 men; mean age, 34.8 ± 6.3 years; age range, 26–47 years) and 25 primary SS (pSS) patients (23 women and 2 men; mean age, 37.7 ± 7.9 years; age range, 25–50 years) with decreased secretory function. The volume of the parotid gland ducts was precisely measured for both groups at single pre- and 6 post-gustatory-stimulated phases. Time-dependent volume change ratio curves were generated, four parameters were derived from the curves: the slope of the increase in the first post-stimulation phase (slope(1st)), the peak value, the time-to-peak, the total saliva secretion post-stimulation. All values were used to quantitatively evaluate the secretory function of the parotid gland. The repeated measurement analysis, Mann-Whitney U test and receiver operating characteristic curve were applied. RESULTS: Time-dependent volume change ratio curves demonstrated that there is a statistically significant difference between the two groups (F = 8.750; p = 0.005). A quickly increasing curve was shown in the volunteer group, whereas a slowly increasing curve was shown in the pSS patient group. The slope(1st), peak value and total saliva secretion post-stimulation of the patient group were significantly lower than those of the volunteer group (p = 0.005, p = 0.003, and p = 0.002, respectively). The time-to-peak between the two groups was not significantly different (p = 0.383). The slope(1st) can be used as a discriminator to diagnose SS patients (p = 0.015; odds ratio = 4.234; area under the curve = 0.726). CONCLUSION: Dynamic MR sialography is proven to be an effective method in evaluating salivary gland function and has a great potential in diagnosing and evaluating pSS patients.

Three-dimensional arterial spin labeling PWI in evaluating postoperative cerebral perfusion changes in patients with Moyamoya disease / 中国医学影像技术

Objective To observe the value of three-dimensional arterial spin labeling (3D-ASL) PWI in evaluating postoperative cerebral perfusion changes in patients with Moyamoya disease.Methods Totally 19 patients of Moyamoya disease confirmed with DSA were enrolled.All the patients received revascularization.Before and after operation,3D-ASL PWI and dynamic susceptibility contrast perfusion weighted imaging (DSC-PWI) were performed.ROI was located in the region with obvious perfusion changes supplied by middle cerebral artery on the operating side.Then the cerebral blood flow (CBF) was measured on 3D-ASL images,and time to peak (TTP) was measured on DSC-PWI images before and after operation.The differences of CBF and TTP before and after operation were compared,as well as the improvement rate of CBF,TTP and clinical symptoms.Results Before and after operation,CBF was (41.40±11.36) ml/(100 g · min) and (54.10±16.69) ml/(100 g · min),respectively,and the difference was statistically significant (t=-4.273,P＜0.01).TTP was (28.66 ± 3.21) s and (26.44 ± 3.93) s,respectively,and the difference was also statistically significant (t =-2.936,P＜0.01).The improvement rate of clinical symptoms was 84.21％ (16/19),of CBF was 78.95％ (15/19) and of TTP was 68.42％ (13/19),the differences of improvement rate had no statistically significant (P=0.625).Conclusion 3D-ASL PWI is noninvasive,no contrast agent need to be used,and can be used to evaluate perfusion changes after operation of revascularization in patients with Moyamoya disease.

Application of amide proton transfer imaging in differentiating glioma from treatment effect / 中华核医学与分子影像杂志

Objective To explore the application of amide proton transfer (APT) imaging in differentiating glioma from treatment effect and to evaluate the diagnostic efficiency of the quantitative APT-related parameters.Methods A total of 23 patients (15 males, 8 females, age: 13-80 years) with 27 lesions who had underwent APT imaging in Tongji Hospital(Wuhan, China) from October 2014 to June 2015 were enrolled in this prospective study.The scan protocols were MRI normal plain scanning, diffusion WI, contrast-enhancement T1WI and APT imaging.Both the magnetization transfer ratio (MTR) and the relative MTR (rMTR) of lesions were manually measured by drawing ROI in the functional post-processing workstation.The results were compared with those of pathologic examinations and radiographic follow-up (≥3 months).Mann-Whitney u test was used to analyze the data.Results Compared with contralateral white matter, the primary gliomas (n=12) and recurrent gliomas (n=8) manifested hyper-intensity, while the treatment induced injuries (n=7) showed iso-or hypo-intensity.The difference of MTR between tumors and treatment effects was significant (102.78(101.93,103.84) vs 100.17(99.94, 100.63);z=-3.76, P<0.01), so was the difference of rMTR between tumors and treatment effects (3.92%(2.69%,4.67%) vs 0.47%(-0.79%,1.11%);z=-3.43, P<0.01).Both those two quantitative parameters exhibited excellent diagnostic performance with the AUC of 0.986 and 0.943.The sensitivity, specificity and accuracy of MTR were 100%(20/20), 6/7 and 96.3%(26/27) in the threshold of 100.68, while those of rMTR were 95.0%(19/20), 6/7 and 92.6%(25/27) in the threshold of 1.66%.Conclusions Combined with the routine MRI images, APT imaging can provide excellent qualitative and quantitative information in differentiating glioma from treatment effect.Both MTR and rMTR are helpful for the differentiation with high sensitivity and specificity and can be used as non-invasive imaging biomarkers in evaluating treatment effect of glioma.

Compare three dimensional arterial spin labeling and dynamic susceptibility contrast perfusion weighted imaging in evaluation of the cerebral hemodynamic of adult Moyamoya patients / 中华放射学杂志

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.

Atlas-based deep gray matter and white matter analysis in Alzheimer's disease：diffusion ;abnormality and correlation with cognitive function / 中华放射学杂志

Objective To identify the diffusion alterations of deep gray matter(GM) and white matter (WM) among Alzheimer's disease (AD), mild cognitive impairment (MCI) and healthy people by atlas?based analysis (ABA), and to investigate the respective relationship with cognitive function. Methods Twenty?one AD patients (AD group), 8 MCI patients (MCI group) and 15 normal controls (control group) were performed by conventional MRI and diffusion tensor imaging (DTI). The raw data of DTI was processed by using DTI studio software to generate the fractional anisotropy (FA) images. Then ABA was used to quantify the FA value in 58 deep GM and WM structures. The differences of FA value among three groups were compared by using one way ANOVA, with a post?hoc analysis. In AD and MCI groups, the partial correlation was further investigated between mini?mental state examination (MMSE) score and FA value in the brain regions that have significant differences between AD and MCI group or between MCI and control group. Results Compared with control group, AD patients showed wide?spread FA decrease in most deep GM and WM regions (corrected P0.05). Conclusion Based on ABA, this study found the diffusion changes not only in the WM but also the deep GM in AD patients, but only WM diffusion disruptions in MCI group. The decreased FA value in the right SCC appeared early, but had no correlation with the cognitive impairment. The FA value in the hypothalamus, the fornix, the SLF and the cingulum decreased with the disease progression, and correlated positively with the cognition decline.

Analysis of intracranial atherosclerotic plaque enhancement using high-resolution MR imaging in patients with ischemic stroke / 中华放射学杂志

Objective To assess the enhancement feature of intracranial atherosclerotic plaque in the vessel supplying the territory of infarction by using high-resolution MR imaging.To analyze the correlation between the degree of plaque enhancement , time elapsed and the concentration of hypersensitive C-reactive protein ( hs-CRP ).Methods The characteristics of vessel walls and intracranial vascular stenoses were retrospectively analyzed in 81 patients with ischemic strokes.All subjects were imaged with a traditional stroke MR protocol and HR-MRI scanning for plaque on a 3.0 T MRI scanner.According to the elapsed time between infarct and MR examination , all cases were classified into early stage (12 weeks, n=10).The characteristics of vessel walls and degrees of enhancement of atherosclerotic plaques were assessed and the concentrations of hs-CRP in all patients were determined.The Kruskal-Wallis H test was used to compare the degree of enhancement and hs-CRP concentration among the early , middle and late stage.The concentration of hs-CRP was presented as median ( interquartile range ).The Spearman correlation was used to analyze the correlation between elapsed time , hs-CRP concentration and degree of enhancement.Results Fifty-five (55/81) plaques were located at the M1 segments, and the other 26 (26/81) plaques were at the basilar artery.The degree and presence of enhancement from strong to none were 29, 25 and 4 in the early stage;4, 6 and 3 in the middle stage and 0, 4, 6 in the late stage, respectively.The degree and presence of enhancement were significantly different among them (H=16.934,P<0.01).There was a remarkable trend of decreasing degree and presence of enhancement of the atherosclerotic plaque relative to increasing time after the ischemic event(r=-0.792,P<0.01).The serum hs-CRP concentration for early, middle and late stage were 7.0(3.0, 13.0), 2.27(1.0, 3.03) and 1.88(0.50, 4.0)mg/L (H=14.345,P<0.01) , respectively.There was a trend of decreasing hs-CRP concentration relative to the time elapsed ( r =-0.357,P<0.01).The degrees of enhancement of the plaques were parallel to the levels of hs -CRP( r=0.526,P<0.01).Conclusions Enhanced HR-MRI scanning may clearly demonstrate the enhancement characteristics of intracranial atherosclerotic plaques as an indicator of inflammation.It might play an important role to detect risk factors for intracranial plaque rupture and subsequent acute ischemic stroke .

A study for the time course of cerebral infarction with diffusion kurtosis imaging / 中华放射学杂志

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.

Two-dimensional Multiple-echo Recalled Gradient Echo Sequence at Flexion Position in the Diagnosis of Hirayama Disease / 中国医学影像学杂志

Purpose To evaluate the diagnostic value of two-dimensional multiple-echo recalled gradient echo (2D MERGE) with flexural position in the hirayama disease. Materials and Methods Conventional MRI and axial MERGE images (7 cases) were analyzed and the anteroposterior diameter was measured at C6 vertebral body, and the structure of spinal, extramedullary and subdural space and extradural space were compared. Results The anteroposterior diameter was (5.7±0.6) cm and (4.7±0.5) cm in the neutral position and flexural position (t=-2.95, P<0.05). The“butterfly”shape of spinal grey matter could not be detected in the 4 cases on MERGE with flexural position, which could not demonstrated on the conventional MR images. 2D MERGE was not sensitive for the CSF flow artefacts and the contrast between spinal and surrounding structures was improved. However, the vascular images could not displayed on 2D MERGE images. Conclusion 2D MERGE sequence is better than T1WI and T2WI on sagittal view and T2WI on axial view in the pathological changes of hirayama disease except flow-empty vein sign, thus it has an important role in diagnosing hirayama disease.

Iterative Reconstruction Algorithm CT Perfusion and Angiography in the Diagnosis of Ischemic Cerebrovascular Disease / 中国医学影像学杂志

Purpose To reconstruct perfusion computerized tomography angiography (PCTA) images from the volume data of low-dose brain CT perfusion scan with iterative reconstruction algorithm, to analyze the capability of PCTA on the display of brain arteries, and to explore the methods to reduce the radiation dose for stroke CT examinations. Materials and Methods This was a prospective study, 55 patients (605 arterial segments) with clinical diagnosis of ischemic cerebrovascular disease underwent cranial CT scan, iterative algorithm low-dose brain CT perfusion scan and conventional cranial CTA examinations using a 256-slice spiral CT. 11 segments of the cerebral artery in each case were analyzed using conventional CTA results as the reference standard to assess the display of brain arteries in PCTA. Results Effective dose of CT perfusion scan was 2.12 mSv. Among the 580 vessel segments which CTA showed no stenosis or stenosis0.75 for the consistency test between PCTA and CTA on the display of brain arteries. Conclusion Radiation dose of iterative algorithm cranial CT perfusion scan is significantly lower, and the images reconstructed from the volume data of perfusion CT are highly consistent with the CTA results, thus are able to meet the needs of the clinical diagnosis.

Investigation on positive correlation of increased brain iron deposition with cognitive impairment in Alzheimer disease by using quantitative MR R2' mapping / 华中科技大学学报（医学）（英德文版）

Brain iron deposition has been proposed to play an important role in the pathophysiology of Alzheimer disease (AD). The aim of this study was to investigate the correlation of brain iron accumulation with the severity of cognitive impairment in patients with AD by using quantitative MR relaxation rate R2' measurements. Fifteen patients with AD, 15 age- and sex-matched healthy controls, and 30 healthy volunteers underwent 1.5T MR multi-echo T2 mapping and T2* mapping for the measurement of transverse relaxation rate R2' (R2'=R2*-R2). We statistically analyzed the R2' and iron concentrations of bilateral hippocampus (HP), parietal cortex (PC), frontal white matter (FWM), putamen (PU), caudate nucleus (CN), thalamus (TH), red nucleus (RN), substantia nigra (SN), and dentate nucleus (DN) of the cerebellum for the correlation with the severity of dementia. Two-tailed t-test, Student-Newman-Keuls test (ANOVA) and linear correlation test were used for statistical analysis. In 30 healthy volunteers, the R2' values of bilateral SN, RN, PU, CN, globus pallidus (GP), TH, and FWM were measured. The correlation with the postmortem iron concentration in normal adults was analyzed in order to establish a formula on the relationship between regional R2' and brain iron concentration. The iron concentration of regions of interest (ROI) in AD patients and controls was calculated by this formula and its correlation with the severity of AD was analyzed. Regional R2' was positively correlated with regional brain iron concentration in normal adults (r=0.977, P<0.01). Iron concentrations in bilateral HP, PC, PU, CN, and DN of patients with AD were significantly higher than those of the controls (P<0.05); Moreover, the brain iron concentrations, especially in parietal cortex and hippocampus at the early stage of AD, were positively correlated with the severity of patients' cognitive impairment (P<0.05). The higher the R2' and iron concentrations were, the more severe the cognitive impairment was. Regional R2' and iron concentration in parietal cortex and hippocampus were positively correlated with the severity of AD patients' cognitive impairment, indicating that it may be used as a biomarker to evaluate the progression of AD.

Diffusion tensor imaging study of Parkinson disease / 中国医学影像技术

Objective To investigate the change of diffusion tensor imaging (DTI) parameters on extracorticospinal tract and some domain in Parkinson disease (PD), and to explore the relationship between DTI parameters and PD. Methods Ten PD patients with unilateral symptoms and 20 with bilateral symptoms were enrolled in PD group 1 and PD group 2, respectively. Control group included 30 volunteers whose age and sex matched with those of PD group. PD patients and the subjects in control group underwent routine MR plain scan and DTI scan. FA and ADC maps were obtained after postprocessing. FA values and ADC values of ROI (region of interest) were measured. ROI included substantia nigra (SN), red nucleus (NR), globus pallidus (GP), putamen (PUT), caudate nucleus (CN), thalamus, genu of corpus callosum, splenium of corpus callosum, callosal gyrus, white matter of frontal lobe and anterior centra gyrus. All data were analyzed statistically. Results FA value of SN, CN, thalamus and splenium of corpus callosum of PD group degraded obviously compared with that of control group (P<0.05). FA value of PD group 1 was lower than control group and PD group 2 at anterior central gyrus and callosal gyrus (P<0.05). There was no significant difference of FA value among PD groups and control group at other ROI's. There was negative correlation between the changes of FA value at SN and PD grade. No significant difference was found in ADC value among PD group 1, PD group 2 and control group, but there was an increasing tendency of ADC value along with the progress of PD. Conclusion FA values of SN, CN, thalamus and splenium of corpus callosum can offer some important information for the early diagnosis of PD. DTI is useful for the study about PD's pathomechanism and clinical manifestation in vivo.

Observation on cerebral microbleeds in patients with hypertension by magnetic resonance imaging / 中华神经科杂志

Objective To concentrate on the morbidity of cerebral microbleed (CMB) in patients with hypertension and to analyze the predilection and risk-factor of cerebral microbleed.Method Hypertensive patients were divided into the simple hypertention group, hypertention group with lacunar infarction and hypertention group with cerebral infarction.All of these 65 patients received examination of susceptibility-weighted imaging.Results Ninety-one focuses of cerebral microbleeds were found in these patients:58.2% of these focuses were in both basal ganglia and cerebral ganglion;35.2 percent were in cortex and subcortex;6.6 percent were in brainstem and cerebellum.The total morbidity of CMB was 33.8 percent, 52.4 percent in the group with lacunar infarction and 38.1 percent in the group with cerebral infarction, both were significantly higher than that of 8.7 percent in the simple hypertensive group (χ2= 8.08,P<0.01 andχ2=3.86, P<0.05).Conclusions The focus of CMB suggested the hemorrhagic tendency in endocranial capillary.CMB can be used as a routine exam for the hemorrhagic tendency in endocranial capillary.Synthetic analysis of risk-factor and the result of SWI help clinicians choose suitable treatment for each patient.

Superparamagnetic iron oxide labeling of neural stem cells and 4.7T MRI tracking in vivo and in vitro / 华中科技大学学报（医学）（英德文版）

Neural stem cells were labeled with superparamagnetic iron oxide (SPIO) and tracked by MRI in vitro and in vivo after implantation. Rat neural stem cells were labeled with SPIO combined with PLL by the means of receptor-mediated endocytosis. Prussian blue staining and electron microscopy were conducted to identify the iron particles in these neural stem cells. SPIO-labeled cells were tracked by 4.7T MRI in vivo and in vitro after implantation. The subjects were divided into 5 groups, including 5 x 10(5) labeled cells cultured for one day after labeling, 5 x 10(5) same phase unlabeled cells, cell culture medium with 25 mug Fe/mL SPIO, cell culture medium without SPIO and distilled water. MRI scanning sequences included T(1)WI, T(2)WI and T(2)*WI. R(2) and R(2)* of labeled cells were calculated. The results showed: (1) Neural stem cells could be labeled with SPIO and labeling efficiency was 100%. Prussian blue staining showed numerous blue-stained iron particles in the cytoplasm; (2) The average percentage change of signal intensity of labeled cells on T(1)WI in 4.7T MRI was 24.06%, T2WI 50.66% and T(2)*WI 53.70% respectively; (3) T2 of labeled cells and unlabeled cells in 4.7T MRI was 516 ms and 77 ms respectively, R(2) was 1.94 s(-1) and 12.98 s(-1) respectively, and T(2)* was 109 ms and 22.9 ms, R(2)* was 9.17 s(-1) and 43.67 s(-1) respectively; (4) Remarkable low signal area on T(2)WI and T(2)*WI could exist for nearly 7 weeks and then disappeared gradually in the left brain transplanted with labeled cells, however no signal change in the right brain implanted with unlabeled cells. It was concluded that neural stem cells could be labeled effectively with SPIO. R2 and R(2)* of labeled cells were increased obviously. MRI can be used to track labeled cells in vitro and in vivo.

Superparamagnetic Iron Oxide Labeling of Neural Stem Cells and 4.7T MRI Tracking in vivo and in vitro / 华中科技大学学报（医学）（英德文版）

Neural stem cells were labeled with superparamagnetic iron oxide (SPIO) and tracked by MRI in vitro and in vivo after implantation. Rat neural stem cells were labeled with SPIO combined with PLL by the means of receptor-mediated endocytosis. Prussian blue staining and electron microscopy were conducted to identify the iron particles in these neural stem cells. SPIO-labeled cells were tracked by 4.7T MRI in vivo and in vitro after implantation. The subjects were divided into 5 groups, including 5× 105 labeled cells cultured for one day after labeling, 5 × 105 same phase unlabeled cells, cell culture medium with 25 μg Fe/mL SPIO, cell culture medium without SPIO and distilled water. MRI scanning sequences included T1WI, T2WI and T2*WI. R2 and R2* of labeled cells were calculated. The results showed: (1) Neural stem cells could be labeled with SPIO and labeling efficiency was 100%. Prussian blue staining showed numerous blue-stained iron particles in the cytoplasm; (2) The average percentage change of signal intensity of labeled cells on T1WI in 4.7T MRI was 24.06%, T2WI 50.66% and T2*WI 53.70% respectively; (3) T2 of labeled cells and unlabeled cells in 4.7T MRI was 516 ms and 77 ms respectively, R2 was 1.94 s-1 and 12.98 s-1 respectively, and T2* was 109 ms and 22.9 ms, R2* was 9.17 s-1 and 43.67 s-1 respectively; (4) Remarkable low signal area on T2WI and T2*WI could exist for nearly 7 weeks and then disappeared gradually in the left brain transplanted with labeled cells, however no signal change in the right brain implanted with unlabeled cells. It was concluded that neural stem cells could be labeled effectively with SPIO. R2 and R2* of labeled cells were increased obviously. MRI can be used to track labeled cells in vitro and in vivo.

Evaluation of large intracranial aneurysms with cine MRA and 3D contrast-enhanced MRA / 华中科技大学学报（医学）（英德文版）

The value of combined application of both ECG-gated cine MRA and 3D-CEMRA in the detection of large intracranial aneurysms was evaluated and the findings were compared with those of conventional MRA and DSA. Twenty-four patients with 26 large intracranial aneurysms underwent MRI and DSA. All these aneurysms, diameter from 15 to 39 mm, were located at internal cerebral artery (n=12), vertebral artery (n=3), basilar artery (n=4), anterior cerebral artery (n=2), middle cerebral artery (n=2), anterior communicate artery (n=2) and posterior communicate artery (n=1). Thirteen cases of hematoma or cavernoma were studied as control group. All patients were examined on GE 1.5T MR system. ECG-gated cine MRA was performed with 2D multi-phase fast gradient-recalled echo sequence in a single section. All the images were analyzed with signal intensity VS time curve for differentiating intraaneurysmal blood flow from static tissue. The results were analyzed by statistic "t" test. 3D-CEMRA was performed with spoiled gradient-recalled echo and one dose of Gd-DTPA. All data was processed with multi-plannar reformat (MPR) and tomography for the demonstration of aneurysms in detail. All 26 aneurysms were demonstrated successfully by combined application of both cine MRA and 3D-CEMRA. Compared to DSA and conventional 3D-MOTSA, its sensitivity and specificity figures were both 100%. Cine MRA could differentiate the blood flow from the static tissue. The intensity VS time curves of intraaneurysmal blood flow offered fluctuating form and average signal change between systole and diastole period was about 89.8 +/- 37.4; However, under the control group, intraaneurysmal thrombus or cerebral hemorrhage or cavernomas had no significant signal change and the curves offered steady form with the average signal change being about 8.2 +/- 6.3. There was statistically significant difference between the intraaneurysmal blood flow and static tissue (P=0.025, <0.05). 3D-CEMRA was very useful in demonstrating the aneurysmal size, intraaneurysmal thrombus formation, neck and the detailed relationship of the aneurysm to the surrounding structures. It was concluded that the combined application of both cine MRA and 3D-CEMRA might be a valuable clinical tool for the detection of large intracranial aneurysms.

Evaluation of large intracranial aneurysms with cine MRA and 3D contrast-enhanced MRA / 华中科技大学学报（医学）（英德文版）

The value of combined application of both ECG-gated cine MRA and 3D-CEMRA in the detection of large intracranial aneurysms was evaluated and the findings were compared with those of conventional MRA and DSA. Twenty-four patients with 26 large intracranial aneurysms underwent MRI and DSA. All these aneurysms, diameter from 15 to 39 mm, were located at internal cerebral artery (n=12), vertebral artery (n=3), basilar artery (n=4), anterior cerebral artery (n=2), middle cerebral artery (n=2), anterior communicate artery (n=2) and posterior communicate artery (n=1). Thirteen cases of hematoma or cavernoma were studied as control group. All patients were examined on GE 1.5T MR system. ECG-gated cine MRA was performed with 2D multi-phase fast gradient-recalled echo sequence in a single section. All the images were analyzed with signal intensity VS time curve for differentiating intraaneurysmal blood flow from static tissue. The results were analyzed by statistic "t" test. 3D-CEMRA was performed with spoiled gradient-recalled echo and one dose of Gd-DTPA. All data was processed with multi-plannar reformat (MPR) and tomography for the demonstration of aneurysms in detail. All 26 aneurysms were demonstrated successfully by combined application of both cine MRA and 3D-CEMRA. Compared to DSA and conventional 3D-MOTSA, its sensitivity and specificity figures were both 100%. Cine MRA could differentiate the blood flow from the static tissue. The intensity VS time curves of intraaneurysmal blood flow offered fluctuating form and average signal change between systole and diastole period was about 89.8 +/- 37.4; However, under the control group, intraaneurysmal thrombus or cerebral hemorrhage or cavernomas had no significant signal change and the curves offered steady form with the average signal change being about 8.2 +/- 6.3. There was statistically significant difference between the intraaneurysmal blood flow and static tissue (P=0.025, <0.05). 3D-CEMRA was very useful in demonstrating the aneurysmal size, intraaneurysmal thrombus formation, neck and the detailed relationship of the aneurysm to the surrounding structures. It was concluded that the combined application of both cine MRA and 3D-CEMRA might be a valuable clinical tool for the detection of large intracranial aneurysms.

Comparative study of 3D-SPGR vs 2D-SE T1WI after enhancement in the brain / 华中科技大学学报（医学）（英德文版）

The utility of three-dimensional spoiled gradient recalled acquisition in steady state (3D-SPGR) imaging in the cerebral diseases was evaluated and 3D-SPGR after enhancement in depicting contrast enhancement of all lesions and 2D-SE T1WI comparatively analyzed. 117 patients were subjected to MRI by a GE 1.5T MR system. After performance of axial T1WI and T2WI in all patients, MRA (3D-MOTSA) images were acquired in 6 cases (8 lesions) of aneurysms. After enhancement, 3D-SPGR images were obtained in all the remaining patients. Quality parameters (SNR, C and CNR) were calculated on enhanced 2D-SE T1WI and 3D-SPGR images. And a four-point scale was used to measure the signal intensity of the main lesions on both sequences, then statistical analysis of the average score was performed with "t" test. Except for aneurysms, 2D-SE T1WI detected 134 lesions and 3D-SPGR disclosed 147 lesions. It was found that there was no statistically significant difference between the two average scores as determined by the "t" test (t = 1,894, P > 0.05). The enhancement degree of the main lesion was equivalent on 3D-SPGR and 2D-SE T1WI. Quality parameters (SNR, C and CNR) on 2D-SE T1WI were much larger than that of 3D-SPGR, increasing by an average of 57%, 20% and 97% respectively. 3D-SPGR imaging with MPR could clearly depict vascularity related to neoplasms in 20 cases and demonstrate shifted, deformed and blocked vessels involved by tumors. Six cases of large aneurysms (8 lesions) were visualized more clearly on 3D-SPGR than MRA (3D-MOTSA): 3D-SPGR could display aneurysm necks and differentiate thrombosed portion from the patent lumen, and disclose relationship of aneurysm to surrounding structures. It was concluded that enhanced 3D-SPGR played an important role in the depiction of the cerebral lesions and was superior to 2D-SE T1WI in many aspects.