Magnetic Resonance Imaging Studies of Neurodegenerative Disease: From Methods to Translational Research / 神经科学通报·英文版

Neurodegenerative diseases (NDs) have become a significant threat to an aging human society. Numerous studies have been conducted in the past decades to clarify their pathologic mechanisms and search for reliable biomarkers. Magnetic resonance imaging (MRI) is a powerful tool for investigating structural and functional brain alterations in NDs. With the advantages of being non-invasive and non-radioactive, it has been frequently used in both animal research and large-scale clinical investigations. MRI may serve as a bridge connecting micro- and macro-level analysis and promoting bench-to-bed translational research. Nevertheless, due to the abundance and complexity of MRI techniques, exploiting their potential is not always straightforward. This review aims to briefly introduce research progress in clinical imaging studies and discuss possible strategies for applying MRI in translational ND research.

Establishment of the DRL and warning dose value for CT examinations in our hospital and its application in chest CT dose optimization / 中华放射医学与防护杂志

Objective:To optimize the scheme and process of chest CT scanning and control the dose level to the examined individuals by establishing the diagnostic reference level (DRL) and warning dose value from chest CT examinations in our hospital.Methods:The medical records for 205 511 examined individuals, who had undergone chest CT scans in the Second Affiliated Hospital of Zhejiang University Medical College from January 1, 2018 to December 31, 2019, were reviewed consecutively. For the two-year examination periods, these examined individuals were divided into two groups, one for 2018 totalling 90 507 and another for 2019 with a total of 115 004. The mean value of doses from chest CT scans in 2018 was set as the DRL for the hospital, with the 75th and 25th percentiles as the upper and lower limits of diagnostic reference range (DRR) and the 97.5th percentiles as the warning dose values. The doses above the upper limit of DRR were considered to be relatively-high whearas the ones exceeding the warning dose value to be over-high. Based on the analysis of the over high dose in 2018, the scanning scheme and inspection process of the chest CT scans were improved in 2019. The number of examinations were estimated for the 2018 period for chest plain CT scans, chest enhancement CT scans, lung cancer screening low-dose CT scans, and relatively-high and over-high dose CT scans, as well as the single scanning doses to the examined in the two groups. The number of examinations resulting in high dose to the examined due to different reasons before and after the improvement were studied. The various parameters on the examined in the two groups were compared statistically.Results:After the improvement, the average dose from chest plain CT scans decreased by 8.67 %, with the statistically significant difference as compared with before improvement ( t=55.71, P<0.05). The average dose from low-dose chest CT scans fell by 20.13% with statistically significant difference ( t=81.99, P<0.05). The fraction of the examinations with slightly-high doses arising from chest plain CT scans and low dose chest CT scans dropped by 3.66% and 17.15%, respectively. The fraction of the examinations with slightly-high dose from chest enhanced CT increased by 1.7%. The fraction of the examinations with over-high dose from chest plain CT scans, enhanced CT scans and low-dose CT scans decreased by 0.55%, 1.06% and 1.74%, respectively. After improvement, the optimized fraction of the examinations with over-high dose, dropped by 4.72%, 31.49% and 19.18% respectively. Conclusions:The establishment of the DRL and the warming dose value of for chest CT examinations in our hospital is helpful to find out the cause of high dose scanning, promote the optimization of dose, reduce the average dose to the examinedes, and avoid using excessive dose during scanning.

Correlation of cardiovascular risk factors with brain iron deposition: A magnetic resonance imaging study / 浙江大学学报·医学版

OBJECTIVE: To study the correlation of common cardiovascular risk factors with brain iron deposition. METHODS: Eighty-four elderly subjects without neurological diseases or brain trauma were included in the study. The cardiovascular risk factors were comprehensively assessed. MRI examination was performed to obtain high-resolution T1-weighted images and enhanced susceptibility weighted angiography (ESWAN) images, and R2* figure was obtained by post-processing the ESWAN sequence. High definition T1 images were segmented using computer segmentation technique. After registration to the ESWAN image, R2* values of each region of interest were extracted. Multiple linear regression analysis was used to analyze the relationship of R2* values in each area of interest with gender, age and vascular risk factors. RESULTS Smoking was associated with increased R2* values in the hippocampus, white matter and cortex (β=0.244, 0.317, 0.277, P<0.05 or P<0.01). Hypertension was correlated with the increase of R2* in the putamen (β=0.241, P=0.027). Hyperglycemia was associated with the increase of R2* in the thalamus (β=0.234, P<0.05). In the thalamus, the R2* value of males was higher than that of females (β=0.320, P<0.05). Age was correlated with the R2* values of thalamus, caudate nucleus, pallidus, white matter and cortex (β=-0.218、-0.254、0.216、-0.280 and -0.238, P<0.05 or P<0.01). CONCLUSIONS Common cardiovascular risk factors may lead to iron deposition in the brain, and the deposition patterns vary with the gender, age and different risk factors.

Diffusion-weighted imaging texture features in differentiation of malignant from benign nonpalpable breast lesions for patients with microcalcifications-only in mammography / 浙江大学学报·医学版

OBJECTIVE@#To evaluate the application of MR diffusion-weighted imaging(DWI) texture features in differentiation of malignant from benign nonpalpable breast lesion for patients with microcalcifications-only in mammography.@*METHODS@#The clinical and MR-DWI data of 61 patients with microcalcifications, who underwent three-dimensional positioning of breast X-ray wire from October 2012 to December 2015 in Zhejiang Cancer Hospital, were retrospectively analyzed, including 38 patients with malignant lesions and 23 patients with benign lesions. Two radiologists independently drew the regions of interest (ROI) on DWI for image segmentation, and 6 histogram features and 16 grayscale symbiosis matrix (GLCM) texture features were extracted on each ROI. The random forest algorithm was applied to select the features and built the classification model. The leave-one-out cross-validation (LOOCV) was used to validate the classifier, and the performance of the classifier was evaluated by ROC curve.@*RESULTS@#Six features were selected, including histogram features of mean, variance, skewness, entropy, as well as contrast (0°) and correlation (45°) in GLCM. The histogram features of mean, variance, skewness and entropy were significantly different between the benign and malignant breast lesions (all <0.05). The AUC of the model was 0.76, and the diagnostic accuracy, sensitivity and specificity were 77.05%, 84.21% and 65.21%, respectively.@*CONCLUSIONS@#The texture feature analysis of DWI can improve the diagnostic accuracy of differentiating benign and malignant breast nonpalpable lesions with microcalcifications-only in mammography. Histogram features of mean, variance, skewness, entropy of DWI may be used as important imaging markers.

Differentiation of pulmonary mucosa-associated lymphoid tissue lymphoma and pulmonary adenocarcinoma by radiomics / 中华放射学杂志

Objective To differentiate between pulmonary mucosa-associated lymphoid tissue lymphoma (MALT) and adenocarcinoma by radiomics, and then evaluate the diagnostic value of this novel approach. Methods We retrospectively analyzed CT images of pulmonary MALT lymphoma (n=16) and invasive pulmonary adenocarcinoma (n=41) and all these cases were confirmed by pathology in the Second Affiliated Hospital of Zhejiang University School of Medicine from June 2012 to June 2017. After we delineated the lesions as region of interest (ROI), sixty-one radiomics features were extracted from each individual's CT images by Radcloud 1.0. All cases in each group were randomly divided into training set (70％cases) and testing set(30％cases), with 7 features (Wilcoxon test) of which showed group differences and were used to train and validate a support vector machine (SVM) classifier. Results Seven of 61 radiomics features showed differences between the two groups, i.e. 10th percentile, mean, median, minimum, total energy, run length non uniformity, gray level non uniformity. Using these 7 features, the resulted SVM successfully differentiated two diseases. The SVM showed high performance with 90％precision, recall 0.89, F1-score 0.87, ROC 0.75. Conclusions Pulmonary MALT and adenocarcinoma differ in radiomics features and machine learning can utilize these features to differentiate between pulmonary MALT and adenocarcinoma. Combination of radiomics and machine learning is promising in the differential diagnosis of these two diseases.

Quantitative evaluation of Ki-67 labeling index in glioma with transfer constant derived from dynamic contrast-enhanced MRI / 中华放射学杂志

Objective To study the value of transfer constant(Ktrans)derived from dynamic contrast-enhanced MRI (DCE-MRI) for quantitative evaluation of Ki-67 labeling index (Ki-67 LI) in glioma. Methods Twenty patients with glioma who underwent DCE-MRI and operation were retrospectively reviewed. The Ktrans value and Ki-67 LI were acquired and correlated using the Spearman correlation test. Also, the Ktrans values were compared between high(larger than 10%)and low(no more than 10%)Ki-67 LI group with Mann-Whitney U test, receiver operating characteristic curves was performed to evaluate the diagnostic value. Results The Ktrans value(0.0165 to 0.8048, median 0.1252)was significantly associated with Ki-67 LI(5%to 50%, median 20%) (r=0.721,P<0.001), and the Ktrans value was significantly higher in high Ki-67 group(0.0810 to 0.8048, median 0.1810)than that in low Ki-67 LI group(0.0165 to 0.1456, median 0.0697)(Z=-3.209, P=0.001). The most predictive Ktrans value differentiated high Ki-67 LI and low Ki-67 LI with an area under the curve(AUC) of 0.945 at a sensitivity of 92.3% and specificity of 85.7%. Conclusion Ktrans value could be used for quantitative evaluation of Ki-67 LI in glioma.

The value of semiquantitative parameters of DCE-MRI in predicting and monitoring efficacy of concurrent chemoradiotherapy in laryngeal and hypopharyngeal carcinoma / 实用放射学杂志

Objective To evaluate the value of semi-quantitative parameters of dynamic contrast-enhanced MRI (DCE-MRI)in predicting and monitoring therapeutic efficacy of concurrent chemoradiotherapy in laryngeal and hypopharyngeal carcinoma.Methods Forty-four patients with pathologically confirmed laryngeal and hypopharyngeal squamous cell carcinoma were collected.Time signal intensity curves (TIC)and related semi-quantitative parameters were obtained before (point 1 ),during (point 2)and after (point 3 )treatment. Tumor remission were assessed at the end of treatment and the statistical analyses were performed using SPSS.Results Twenty two patients had a complete remission as CR group and 22 had a partial remission as PR group.The parameters of time to peak (TTP), maximum signal enhancement ratio (SERmax ),positive enhancement integral (PEI),SER70 and SER84 at point 1 were higher than those at point 2,and there were significant differences between two groups (P <0.05).The values of SERmax ,SER42 ,SER56 ,SER70 and SER84 before treatment were higher in CR group than those in PR group,exhibiting significant differences between two groups (P <0.05).ROC curve analysis showed the threshold for SER56 was set to ≥129.4％ to predict complete remission,and the sensitivity and specificity were 60％ and 86.4％,respectively.Comparison of remission rates among different types of TIC showed complete remission rates in typeⅠTIC and type Ⅲ TIC were 87.5％ and 39.3％,respectively,exhibiting a significant difference between two groups (P =0.041). Conclusion TIC types and semi-quantitative parameters of DCE-MRI can predict therapeutic efficacy of concurrent chemoradiotherapy in laryngeal and hypopharyngeal carcinoma,SER56 is the most important predictive semi-quantitative parameter,and prognosis is much better in typeⅠTIC than type Ⅲ TIC before treatment.

The value of semiquantitative parameters of DCE-MRI in predicting and monitoring efficacy of concurrent chemoradiotherapy in laryngeal and hypopharyngeal carcinoma / 实用放射学杂志

Objective To evaluate the value of semi-quantitative parameters of dynamic contrast-enhanced MRI (DCE-MRI)in predicting and monitoring therapeutic efficacy of concurrent chemoradiotherapy in laryngeal and hypopharyngeal carcinoma.Methods Forty-four patients with pathologically confirmed laryngeal and hypopharyngeal squamous cell carcinoma were collected.Time signal intensity curves (TIC)and related semi-quantitative parameters were obtained before (point 1 ),during (point 2)and after (point 3 )treatment. Tumor remission were assessed at the end of treatment and the statistical analyses were performed using SPSS.Results Twenty two patients had a complete remission as CR group and 22 had a partial remission as PR group.The parameters of time to peak (TTP), maximum signal enhancement ratio (SERmax ),positive enhancement integral (PEI),SER70 and SER84 at point 1 were higher than those at point 2,and there were significant differences between two groups (P <0.05).The values of SERmax ,SER42 ,SER56 ,SER70 and SER84 before treatment were higher in CR group than those in PR group,exhibiting significant differences between two groups (P <0.05).ROC curve analysis showed the threshold for SER56 was set to ≥129.4％ to predict complete remission,and the sensitivity and specificity were 60％ and 86.4％,respectively.Comparison of remission rates among different types of TIC showed complete remission rates in typeⅠTIC and type Ⅲ TIC were 87.5％ and 39.3％,respectively,exhibiting a significant difference between two groups (P =0.041). Conclusion TIC types and semi-quantitative parameters of DCE-MRI can predict therapeutic efficacy of concurrent chemoradiotherapy in laryngeal and hypopharyngeal carcinoma,SER56 is the most important predictive semi-quantitative parameter,and prognosis is much better in typeⅠTIC than type Ⅲ TIC before treatment.

Medical imaging in tumor precision medicine: opportunities and challenges / 浙江大学学报·医学版

Tumor precision medicine is an emerging approach for tumor diagnosis, treatment and prevention, which takes account of individual variability of environment, lifestyle and genetic information. Tumor precision medicine is built up on the medical imaging innovations developed during the past decades, including the new hardware, new imaging agents, standardized protocols, image analysis and multimodal imaging fusion technology. Also the development of automated and reproducible analysis algorithm has extracted large amount of information from image-based features. With the continuous development and mining of tumor clinical and imaging databases, the radiogenomics, radiomics and artificial intelligence have been flourishing. Therefore, these new technological advances bring new opportunities and challenges to the application of imaging in tumor precision medicine.

Correlation between high signal intensity in cerebrum nucleus on unenhanced T-weighted MR images and number of previous gadolinium-based contrast agent administration / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To explore the correlation between the number of previous gadolinium-based contrast agent administrations and high signal intensity (SI) in the cerebrum nucleus on unenhanced T-weighted magnetic resonance images.</p><p><b>METHODS</b>Thirty-nine patients who previously underwent at least three contrast-enhanced brain MRI examinations were enrolled in the study. The right globus pallidus, right thalamus, right dentate nucleus, pons and white matter of right frontal lobe were selected as region of interests (ROI). The mean SIs of the ROI were measured on unenhanced T-weighted images. The SI ratios of globus pallidus, right thalamus, right dentate nucleus and pons to white matter were calculated, respectively. The correlation of SI ratio variation with the number of previous contrast agent administration and clinical features was analyzed with Spearman analysis.</p><p><b>RESULTS</b>The dentate nucleus-to-white matter SI ratios of the last and first MRI scan were 1.113±0.136 and 1.014±0.096(<0.01), respectively; while the SI ratio differences between the last and first MRI scan of globus pallidus-to-white matter, the thalamus-to-white matter and the pons-to-white matter were not significant (all>0.05). The dentate nucleus-to-white matter SI ratio was correlated with the number of previous gadolinium-based contrast agent administrations (=0.329,<0.05), but not with age, sex, underlying disease, treatment and history of diabetes (all>0.05).</p><p><b>CONCLUSIONS</b>High SI in the dentate nucleus on unenhanced T-weighted images may be a consequence of the number of previous gadolinium-based contrast agent administrations.</p>

Quantitative analysis of enhanced MRI features for predicting epidermal growth factor receptor gene amplification in glioblastoma multiforme with radiomic method / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To assess the value of contrast enhanced MRI features for predicting epidermal growth factor receptor () gene amplification in glioblastoma multiforme (GBM) with radiomic method.</p><p><b>METHODS</b>Eighty patients withstatus examined GBM were retrospectively reviewed. The data were randomly divided into a training dataset (60%) and test dataset (40%). Texture features of each case were extracted from the enhanced region and the edema region in contrast enhanced MR images. Principal component analysis was used for dimension reduction. Random forest model, support vector machine model and neural network model were built. Area under the curve (AUC) of the receiver operating characteristics curve was used to assess the performance of models with test dataset.</p><p><b>RESULTS</b>A total of 542 features were extracted from the enhanced region and the edema region. Forty-eight principal components were obtained, which accounted for 100% accumulation contribution rate, and the first 31 principal components were selected for models building, which accounted for 98.5% accumulation contribution rate. The values of AUCs were 0.74, 0.69 and 0.63 for random forest model, support vector machine model and neural network model in the test dataset, respectively.</p><p><b>CONCLUSIONS</b>Radiomic method with proper model may have a potential role in predicting thegene status with enhanced MRI features derived from the enhanced region and the edema region in patients with glioblastoma multiforme.</p>

Diagnostic value of dual energy CT for lymph node metastasis in patients with non-small cell lung cancer / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To assess the diagnostic value of dual energy CT for lymph node metastasis in patients with non-small cell lung cancer (NSCLC).</p><p><b>METHODS</b>Forty NSCLC patients, including 15 cases of squamous cell carcinoma and 25 cases of adenocarcinoma, underwent dual energy CT examination in pre-contrast and venous phase contrast scans, then the CT attenuation value of the lung cancer lesions and 85 mediastinal enlarged lymph nodes (the short diameter ≥ 5 mm, 53 metastatic and 32 non-metastatic) were measured at different energy levels (40-190 keV, spacing 10 keV) in venous phase contrast. CT spectral curves of the lung cancer lesions, hilus pulmonis and mediastinal enlarged lymph nodes were produced automatically, through comparing their CT spectral curves slope to judge whether or not the lymph nodes were metastatic. Receiver operating characteristic (ROC) curve was used to evaluate the efficiency of CT spectral curve in diagnosis of lymph node metastasis.</p><p><b>RESULTS</b>The CT spectral curves slopes of the lung cancer, metastatic lymph nodes and non-metastatic lymph nodes were 1.10±0.11, 1.08±0.07 and 1.54±0.17, respectively. There was no significant difference in curve slope between metastatic lymph nodes and lung cancer (=-1.32,>0.05); while there was significant difference between non-metastatic lymph nodes and lung cancer (=-2.58,<0.05). The CT spectral curve slope ratios of metastatic and non-metastatic lymph nodes to lung cancer were 0.98±0.05 and 1.40±0.12, respectively (=-2.86,<0.05). ROC curve showed that taking CT spectral curve slope ratio of 1.15 as cut-off value for the diagnosis of metastatic lymph nodes, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 81.1%, 87.5%, 91.5%, 73.7% and 83.5%, respectively.</p><p><b>CONCLUSIONS</b>Dual energy CT is of value in improving the diagnostic accuracy of lymph node metastasis in NSCLC patients before treatment.</p>

Application of CT scan in diagnosis of pathological type and origin of metastatic ovarian tumors / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To evaluate the application of CT scan in diagnosis of pathological types and origins of metastatic ovarian tumors.</p><p><b>METHODS</b>Clinical data, histopathological results and CT images of 43 patients with pathologically-proved metastatic ovarian tumor were retrospectively analyzed. Diagnostic values of CT imaging for pathological type and origin of metastatic ovarian tumors were evaluated.</p><p><b>RESULTS</b>The pathological types of metastatic ovarian tumor were related to the size of the lesion (<0.01), while not related to the sites of lesion (unilateral or bilateral), the cystic-solid and mixed lesions with or without separation (all>0.05). Metastatic ovarian tumors of colorectal origin were usually unilateral lesions, and showed cystic or cystic-solid masses, while those of gastric origin were usually bilateral lesions, and showed solid or solid-based masses.</p><p><b>CONCLUSIONS</b>CT imaging may be of value in diagnosis of pathological types and origin of metastatic ovarian tumor.</p>

Using dynamic contrast-enhanced MRI to predict the histopathologic grade of cerebral gliomas / 中华放射学杂志

Objective To evaluate three different tracer-kinetic models used for dynamic contrast-enhanced MRI (DCE-MRI) data processing in the prediction of the histopathologic grade of cerebral gliomas.Methods Forty-one patients with histopathologically graded gliomas (grade Ⅱ 13,grade Ⅲ 14,grade Ⅳ 14)were imaged with DCE-MRI from March,2013 to November,2014.The values of Ktrans of gliomas were obtained by three tracer-kinetic models,which were Patlak model,Tofts model and Extended Tofts Linear model.All data were analyzed statistically by a Graphpad 6.0 statistical software.Comparison of the differences of Ktrans among different grades of gliomas was conducted using the Kruskal-Wallis test and Dunn's multiple comparisons test for the data not conform to normal distribution.Correlations of Ktrans values among those three models were analyzed using linear regression analysis,The differences of Ktrans between low grades and high grades of gliomas was conducted using the Mann-Whitney U test.Receiver operating characteristic (ROC) curve analyses were performed to determine the cut-off values for Ktrans to distinguish different low grades and high grades of gliomas.Results The Ktrans values obtained by Patlak model was 0.008(0.004-0.043) min-1for grade Ⅱ,0.021(0.005-0.088) min-1 for grade Ⅲ,and 0.035(0.017-0.061) min-1 for grade Ⅳ.The Ktrans values obtained by Tofts model was 0.085 (0.041-0.158)min 1for grade Ⅱ,0.140 (0.063-0.315) min-1for grade Ⅲ,0.229 (0.126-0.419)min 1 for grade Ⅳ.The Ktrans values obtained by Extended Tofts Linear model was 0.012 (0.004-0.092) min 1 for grade Ⅱ,0.048 (0.010-0.188) min-t for grade Ⅲ,0.094 (0.036-0.215)min 1 for grade Ⅳ.All the Ktrans values obtained by three models increased when the histological grades increased,with statistical significance between grade Ⅱ and Ⅲ (H=18.31,18.09,20.18,P＜0.05).Ktrans values among the three models had good linear correlations.The Ktrans obtained by Extended Tofts Linear model had good linear correlations with both Patlak model and Tofts model (r=0.933,0.893,P＜0.05),and the Ktrans obtained by Patlak model had less linear correlation with Tofts model (r=0.822,P＜0.05).The K values were statistically different between LGG and HGG (P＜0.01).The cut-off value of K provided good combination of sensitivity and specificity in the differentiation between LGG and HGG,and the K obtained by Extended Tofts Linear model had the best sensitivity and specificity among the three models (sensitivity 92.3％,specificity 85.7％).Conclusions K from DCE-MRI has a high performance in predicting the histopathologic grade of brain glioma,and the Extended Tofts Linear model is more suitable for the evaluation of cerebral glioma.

Imaging findings of giant cell tumor of tendon sheath / 中华放射学杂志

Objective To explore the imaging features of giant cell tumor of tendon sheath(GCTTS) so as to improve the accuracy of imaging diagnosis. Methods Thirty?nine cases of GCTTS confirmed by pathological examination were retrospectively analyzed.Of the 39 cases, 32 were diffuse form and 7 were localized form.Seventeen patients underwent X?ray examination,18 had CT pain examination,37 had pain MR imaging and 17 had contrast?enhanced MR imaging.Results X?ray showed local soft tissue masswith slightly high density, and the adjacent bones were shown destruction or erosion tovarious degrees(10/17). No obvious calcification and periosteal reaction were shown.CT scans could provide images better than X?ray films.CT showed local soft tissue masses in the peri?articular muscle gaps. Some tumors were lobulated with cross?jointed growth(8/18),and the adjacent bones were shown destruction or erosion tovarious degrees(11/18).No obvious calcification and periosteal reaction were shown. On MRI,most cases were isointense on T1WI(32/37),and hyperintense on T2WI(27/37). Most cases tended to be heterogeneously enhanced following Gd?DTPA administration(14/17).The lesions were typically located adjacent to a tendon or partially/completely encasing it. Conclusions The imaging findings of GCTTS have some certain characteristics. MRI is able to depict the characteristic internal signal of GCTT and its relationship with adjacent tissues, which is valuable for diagnosis, treatment and follow?up.

Advance in studies on dopamine system related genetic polymorphisms associated with nicotine dependence / 中华医学遗传学杂志

Nicotine is the main component for smoking addiction. It is widely believed that nicotine dependence is heritable. Many studies are committed to study the effects of specific gene polymorphisms connect with nicotine dependence. Release of dopamine has been considered the most important channel for nicotine dependence. This paper provides a review for recent advance in studies on dopamine system related genetic polymorphisms associated with nicotine dependence.

Alberta stroke programme early CT score on diffusion-weighted imaging and clot burden scoring on MR angiography in the prediction of hemorrhagic transformation after thrombolysis in acute cerebral infarction / 中华放射学杂志

Objective To evaluate Alberta stroke programme early CT score on diffusion-weighted imaging (DWI-ASPECTS)and clot burden score on MR angiography (MRA-CBS)in predicting hemorrhagic transformation(HT) in acute anterior circulation cerebral infarction after thrombolysis in diffusion-weighted imaging Alberta stroke program.Methods A total of 37 consecutive patients with acute anterior circulation cerebral infarction were treated with thrombolysis.The clinical information , score of DWI-ASPECTS before thrombolysis , score of MRA-CBS before thrombolysis and images of enhanced gradient echo T 2*-weighted angiographywithin ( ESWAN) 24 hours before and after thrombolysis were all collected.The interval between onset and the two MRI scans were recorded respectively.We identified HT according to the images of ESWAN scanned after thrombolysis , and divided patients into 2 groups:with HT(14 cases) and without HT (23 cases).Differences of clinical data and imaging indicators between the two groups were compared by using Fisher′s exact test and Wilcoxon rank sum test.Logistic regression analysis was performed by taking HT as the dependent variable , and the scores of NIHSS , DWI-ASPECTS and MRA-CBS at admission were taken as independent variables.The variables which were statistically significant in logistic regression analysis were enrolled in receiver operating characteristic analysis.Results In HT group, the scores of NIHSS, DWI-ASPECTS and MRA-CBS were 15.00 ±5.30, 6.00(4.75,7.00) and 7.00(0.75,8.50) respectively.In the other group without HT, these scores were 7.00 ±4.80, 9.00(8.00,10.00)and 10.00(6.00,10.00) respectively.Compared with patients without HT , patients with HT had a higher baseline NIHSS score ( Z=-3.72,P<0.01), a lower DWI-ASPECTS (Z=-4.13,P<0.01) and a lower MRA-CBS (Z=-2.00, P<0.05).Logistic regression analysis showed that the scores of DWI-ASPECTS ( OR 0.42,95%CI 0.21-0.87,P <0.05 ) and NIHSS ( OR 1.22, 95%CI 1.00-1.48, P <0.05 ) at baseline predicted HT development independently.Receiver operating characteristic analysis showed that the optimal cut -off point of DWI-ASPECTS to predict the development of HT was≤7.Its sensitivity, specificity and area under ROC curve were 92.9%, 78.3% and 0.902 respectively ( P<0.01 ).Conclusions ASPECTS on DWI is of great value in predicting HT after thrombolysis in acute cerebral infarction.CBS on MRA can provide additional information for predicting HT.

Initial investigation of magnetic resonance perfusion-weighted imaging in leukoaraiosis / 中华老年医学杂志

Objective To investigate whether perfusion-weighted imaging (PWI) can be used to evaluate blood perfusion of patients with leukoaraiosis (LA), its relationship to clinical features, and the therapy effect of LA. Methods The 44 patients with LA were recruited in the study. All the subjects were examined with both conventional and dynamic susceptibility contrast-enhanced perfusion MR imaging, 13 of them repeated the examinations after the treatment. The shapes and sizes of the biggest lesions in each patient were confirmed by conventional MR imaging, then the values of relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF) and relative mean transit time (rMTT) in each lesion were calculated respectively. Furtherly, a Pearson's correlation analysis was performed to show whether these values were correlated with mini-mental state examination (MMSE)scores or activities of daily living (ADL) scores. Results The 44 lesions of all the subjects showed significant decreases in rCBV (0. 797 ± 0. 160) and rCBF (0. 779± 0. 164) but increase in rMTT (1. 029±0. 073). There were positive correlations between rCBV and MMSE (r = 0. 524, P =0. 000), between rCBV and ADL (r=0. 621, P=0. 000), between rCBF and MMSE (r=0. 555, P=0. 000), and between rCBF and ADL (r= 0. 690, P= 0. 000), and negative correlations between rMTTand MMSE (r=-0.307, P=0.043), and between rMTT and ADL (r=-0.434, P=0. 003). The blood perfusion was enhanced in 10 out of 13 patients who received the repeated examinations after the treatment, most of whom showed the improvement of clinical symptoms.Conclusions Perfusion MR imaging can assess hemodynamic alterations in LA, which could reflect the clinical symptoms. Moreover, the changes of blood perfusions can be used to evaluate and monitor the therapy effect of LA.

Microsurgical treatment in aneurysms of anterior circulation / 中华显微外科杂志

Objective To summarize the method and experience of microsurgical treatment of intracranial aneurysms in anterior circulation. Methods The clinical data, the skills and experience of 171 cases with aneurysmso of anterior circulation within the latest 2 years. Results One hundred and seventy-one patients under surgery, including 67 PCOA aneurysm, 56 ACoA aneurysm, 32 MCA aneurysm, 10 ICA aneurysm, OphA aneurysm and 3 haimess aneurysm. Accoring to Glasgow Prognostic Scale, there were 3 cases of grade Ⅰ, 6 cases of grade Ⅲ, 14 cases of grade Ⅳ and 148 cases of grade Ⅴ. Conclusion The key points to cure intracranial aneurysms successfully is favourable exposure and the skills of microsurgery; the factors of intluent surgery include forcejudgement in surgery, reasonable choice of aneurysm clips, correctly block in arterious.

Age-related deposition of brain iron in normal adults:an in vivo susceptibility weighted imaging study / 中华放射学杂志

Objeetive The purpose of this study was to investigate the effect of age on the iron concentration of the human brain.Methotis The brain iron level wag evaluated in vivo in 78 healthy adult volunteers using a noninvasive magnetic resonance method termed susceptibility weighted jmaging.The subjects were divided into three groups due to different ages:young(22-35 years old,n=27),middleaged(36-55 years old,n=35),and aged(56-78 years old.n=16).The phase values were measured on the corrected phase images in the giohus pallidus,putamen,caudate,substantia nigra,red nucleus,thalamus and frontal white matter.The phase values of those regions measured from the subjects over than 30 years old were correlated with published valnes of brain iion concentration in normal adults to check the validity of the data.Then,the phase values of the three groups were tested for significant age-related differences using one-way ANOVA,foUowed by post hoc testing using least significant difference(LSD)procedure.Regression analysis wflg used to further examine age.related effects revealed by group compagisons,and to estimate the rates of age-related changes.Results A strong negative correlation was found between the phase values and the published values ofthe brain iron concentration(r=-0.796.P=0.032),which indicated that the hisher the imn deposition level.the greater the negative phase values.In the putamen(F=20.115,P＜0.01)and frontal white matter(F=3.536,P=0.034),significant differences were detected in the phase value$ofthe three age groups.Linear regression analysis showed that phase values of the putamen,frontal white matter,and red nucleus decreased with age(The regression coefficients were-0.001,-0.001,and＜-0.001 respectively,and the P value were all＜0.05),which indicated that the iron concentration of those brain structures increased with age.No significant agerelated changes of the iron concentration were found in the globus pallidus,caudate,substantia nigra,and thalamus.Conclusions These findings extended our knowledge of the patterns of the brain iron accumulation in normal aging.Such information is necessary to understand disease-related changes that involve the brain iron deposition.