Utilidad de la secuencia de susceptibilidad como predictor de penumbra en la isquemia cerebral aguda / Utility of susceptibility sequence as a predictor of penumbra in acute cerebral ischemia

Resumen Objetivo: El objetivo del tratamiento en accidente cerebrovascular (ACV) isquémico agudo es restablecer la circulación en el área de la penumbra isquémica. La secuencia de susceptibilidad (SWI) puede detectar cambios en el calibre de las venas intracraneanas cuando se altera la relación desoxiHb/oxiHb en áreas hipoperfundidas, lo que permitiría una detección temprana de penumbra isquémica. Material y métodos: Estudio de cohorte retrospectivo. Se incluyeron pacientes con infartos agudos en territorio de la arteria cerebral media. Se evaluaron las secuencias difusión y SWI iniciales y un estudio de control a los siete días. La extensión del ACV se midió con la escala ASPECT en difusión y SWI del ingreso, y en el estudio de control. Se estableció una discordancia SWI/difusión > 2 puntos como variable predictora y la extensión final del infarto como variable de resultado. Resultados: Se incluyeron 31 pacientes, mediana de edad de 72 años (RIC: 61-81). En 13 pacientes se detectó una oclusión vascular proximal, ocho de los cuales tenían discordancia SWI/difusión > 2 puntos (p < 0,0001). En cinco pacientes encontramos incremento del infarto, cuatro con discordancia SWI/difusión (p = 0,01). Conclusión: La presencia de discordancia SWI/difusión puede ser un biomarcador de penumbra isquémica en pacientes con oclusión vascular proximal.

Abstract Objective: The goal of treatment in acute ischemic stroke is to restore circulation in the area of the ischemic penumbra. Susceptibility weighted imaging (SWI) can detect changes in the caliber of intracranial veins when the deoxyHb/oxyHb ratio is altered in hypoperfused areas, which would allow early detection of ischemic penumbra. Material and methods: Retrospective cohort study. Patients with acute infarcts in the territory of the middle cerebral artery were included. Initial diffusion and SWI sequences and a control study at seven days were evaluated. Stroke extension was measured with the ASPECT scale in diffusion and SWI on admission, and in the control study. An SWI/diffusion discrepancy > 2 points was established as a predictor variable and the final extension of the infarct as a result variable. Results: Thirty-one patients were included, median age 72 years (IQR: 61-81). Proximal vascular occlusion was detected in 13 patients, 8 of whom had SWI/diffusion discordance > 2 points (p < 0.0001). In 5 patients we found increased infarction, 4 with SWI/diffusion mismatch (p = 0.01). Conclusion: The presence of SWI/diffusion mismatch may be a biomarker of ischemic penumbra in patients with proximal vascular occlusion.

SWI/SNF Complex Gene Mutations Promote the Liver Metastasis of Non-small Cell Lung Cancer Cells in NSI Mice / 中国肺癌杂志

BACKGROUND@#The switch/sucrose nonfermentable chromatin-remodeling (SWI/SNF) complex is a pivotal chromatin remodeling complex, and the genomic alterations (GAs) of the SWI/SNF complex are observed in several cancer types, correlating with multiple biological features of tumor cells. However, their role in liver metastasis of non-small cell lung cancer (NSCLC) remains unclear. Our study aims to investigate the role and potential mechanisms underlying NSCLC liver metastasis induced by the GAs of SWI/SNF complex.@*METHODS@#The GAs of SWI/SNF complex in NSCLC cell lines (H1299, H23 and H460) were identified by whole-exome sequencing (WES). ARID1A knockout H1299 cell was constructed with the CRISPR/Cas9 technology. The mouse model of liver metastasis from NSCLC was established to simulate lung cancer liver metastasis and observe the metastasis rate under different gene mutation conditions. RNA sequencing and Western blot were conducted for differential gene expression analysis. Immunohistochemistry (IHC) analysis was used to assess protein expression levels of SWI/SNF-regulated target molecules in mouse liver metastases.@*RESULTS@#WES analysis revealed intracellular gene mutations. The animal experiments demonstrated a correlation between the GAs of SWI/SNF complex and a higher liver metastasis rate in immunodeficient mice. Transcriptome sequencing and Western blot analysis showed upregulated expression of ALDH1A1 and APOBEC3B in SWI/SNF-mut cells, particularly in ARID1A-deficient H460 and H1299 sgARID1A cells. IHC staining of mouse liver metastases further demonstrated elevated expression of ALDH1A1 in the H460 and H1299 sgARID1A group.@*CONCLUSIONS@#This study underscores the critical role of the GAs of SWI/SNF complex, such as ARID1A and SMARCA4, in promoting liver metastasis of lung cancer cells. The GAs of SWI/SNF complex may promote liver-specific metastasis by upregulating ALDH1A1 and APOBEC3B expression, providing novel insights into the molecular mechanisms underlying lung cancer liver metastasis.

SMARCA2 deficiency in NSCLC: a clinicopathologic and immunohistochemical analysis of a large series from a single institution

BACKGROUND@#SMARCA2 (SWI/SNF Related, Matrix Associated, Actin Dependent Regulator of Chromatin, Subfamily A, Member 2) is an important ATPase catalytic subunit in the switch-sucrose nonfermenting (SWI/SNF) complex. However, its relationship with the pathological features of NSCLC and its prognosis remain unclear.@*METHODS@#We retrospectively reviewed 2390 patients with surgically resected NSCLC, constructed tissue microarrays (TMAs) and performed immunohistochemical assays. We analyzed the correlation of SAMRCA2 with clinicopathological features and evaluated its prognostic value.@*RESULTS@#Among 2390 NSCLC cases, the negative expression ratios of SAMRCA2, SMARCA4, ARID1A, ARID1B and INI1 were 9.3%, 1.8%, 1.2%, 0.4% and 0%, respectively. In NSCLC, male sex, T3 and T4 stage, moderate and poor differentiation, tumor ≥ 2 cm, Ki67 ≥ 15%, SOX-2 negative expression, middle lobe lesion and adenocarcinoma were relative risk factors affecting SMARCA2-negative expression. In lung adenocarcinomas, high-grade nuclei, histological morphology of acinar and papillary, solid and micropapillary and TTF-1-negative expression were relative risk factors affecting SMARCA2-negative expression. Kaplan-Meier survival analysis showed that the OS was shorter in the SMARCA2-negative group. Multivariate survival analysis revealed that SMARCA2-negative expression was an independent factor correlated with a poor prognosis in NSCLC.@*CONCLUSION@#In conclusion, SMARCA2-negative expression is an independent predictor of a poor outcome of NSCLC and is a potential target for NSCLC treatment.

Role and treatment of ARIDIA in mutant tumors / 中国药理学通报

ARIDI A encodes a non-catalytic subunit of SWI/SNF chromosome remodeling complex BAF. Cancer genome sequencing data based on next-generation sequencing techniques have shown that ARIDIA is frequently mutated in a variety of cancers, up to 20% in some cancer types. A growing body of evidence shows that ARIDIA, as a tumor suppressor gene, affects the occurrence and development of cancers. ARIDIA plays an important role in cell cycle, DNA replication, DNA repair and transcriptional regulation, which might contribute to tumor formation, proliferation and migration. This review article mainly describes the research progress on ARIDIA in pan-cancer, as well as potential therapeutics, hoping to provide new ideas for the diagnosis and treatment of tumors.

Characteristic of brain microbleeds in Alzheimer's disease / 上海交通大学学报（医学版）

Objective: To evaluate the differences of brain microbleeds among Alzheimer's disease (AD), amnesia mild cognitive impairment (aMCI) and normal control (NC). Methods: Eighteen AD patients, 28 aMCI patients and 30 age-matched NC were recruited in the study. The location and number of microbleeds was recorded in the brain according to the susceptibility-weighted images. The bilateral frontal lobe, parietal lobe, occipital lobe, temporal lobe, and thalamus were manually mapped on 3D-MR imaging. The number of cases with microbleeds and the number of microbleeds in each lobe were calculated and compared among three groups using the chi-square test and ANOVA. Results: Significant differences on case number with microbleeds were found between AD group and NC group in the frontal lobe (P=0.005), the temporal lobe (P=0.005) and whole brain (P=0.004), and between aMCI group and NC group in the frontal lobe (P=0.048). It also showed significant differences among three groups in the frontal lobe (P=0.006), the temporal lobe (P=0.006) and whole brain (P=0.016). For the microbleeds counts, significant differences were found between AD group and NC group in the frontal lobe (P=0.004) and the temporal lobe (P=0.049), and between AD group and NC group in the frontal lobe (P=0.044). It also had significant differences among three groups in the frontal lobe (P=0.016), the temporal lobe (P=0.038) and whole brain (P=0.048). Conclusion: The AD group has more significant microbleeds in frontal and parietal lobes in comparison to NC group. The quantization of cerebral microbleeds may be a potential biomarker for AD diagnosis.

The SWI/SNF chromatin-remodeling factors BAF60a, b, and c in nutrient signaling and metabolic control

Metabolic syndrome has become a global epidemic that adversely affects human health. Both genetic and environmental factors contribute to the pathogenesis of metabolic disorders; however, the mechanisms that integrate these cues to regulate metabolic physiology and the development of metabolic disorders remain incompletely defined. Emerging evidence suggests that SWI/SNF chromatin-remodeling complexes are critical for directing metabolic reprogramming and adaptation in response to nutritional and other physiological signals. The ATP-dependent SWI/SNF chromatin-remodeling complexes comprise up to 11 subunits, among which the BAF60 subunit serves as a key link between the core complexes and specific transcriptional factors. The BAF60 subunit has three members, BAF60a, b, and c. The distinct tissue distribution patterns and regulatory mechanisms of BAF60 proteins confer each isoform with specialized functions in different metabolic cell types. In this review, we summarize the emerging roles and mechanisms of BAF60 proteins in the regulation of nutrient sensing and energy metabolism under physiological and disease conditions.

Susceptibility Weighted Imaging of the Cervical Spinal Cord with Compensation of Respiratory-Induced Artifact

PURPOSE: The objective of this study was to obtain improved susceptibility weighted images (SWI) of the cervical spinal cord using respiratory-induced artifact compensation. MATERIALS AND METHODS: The artifact from B0 fluctuations by respiration could be compensated using a double navigator echo approach. The two navigators were inserted in an SWI sequence before and after the image readouts. The B0 fluctuation was measured by each navigator echoes, and the inverse of the fluctuation was applied to eliminate the artifact from fluctuation. The degree of compensation was quantified using a quality index (QI) term for compensated imaging using each navigator. Also, the effect of compensation was analyzed according to the position of the spinal cord using QI values. RESULTS: Compensation using navigator echo gave the improved visualization of SWI in cervical spinal cord compared to non-compensated images. Before compensation, images were influenced by artificial noise from motion in both the superior (QI = 0.031) and inferior (QI = 0.043) regions. In most parts of the superior regions, the second navigator resulted in better quality (QI = 0.024, P < 0.01) compared to the first navigator, but in the inferior regions the first navigator showed better quality (QI = 0.033, P < 0.01) after correction. CONCLUSION: Motion compensation using a double navigator method can increase the improvement of the SWI in the cervical spinal cord. The proposed method makes SWI a useful tool for the diagnosis of spinal cord injury by reducing respiratory-induced artifact.

Advantages and disadvantages of magnetic resonance susceptibility effect applied clinically and countermeasures / 医疗卫生装备

Objective To explore the advantages and disadvantages of magnetic resonance susceptibility effect applied clinically and countermeasures. Methods The application range of susceptibility weighted imaging (SWI) technique and the harm of susceptibility artifact were introduced with considerations on MRI clinical application and experiences, and then some countermeasures were put forward accordingly. Results SWI technique could be used for the diagnoses of multi diseases, and susceptibility artifact could be suppressed by sequence, parameter and corresponding techniques. Conclusion Susceptibility effect contributes to extending the clinical application of MRI, and references are provided for the development and reform of other new techniques.

Ovarian Clear Cell Carcinoma Sub-Typing by ARID1A Expression

PURPOSE: Loss of AT-rich DNA-interacting domain 1A (ARID1A) has been identified as a driving mutation of ovarian clear cell carcinoma (O-CCC), a triple-negative ovarian cancer that is intermediary between serous and endometrioid subtypes, in regards to molecular and clinical behaviors. However, about half of O-CCCs still express BAF250a, the protein encoded by ARID1A. Herein, we aimed to identify signatures of ARID1A-positive O-CCC in comparison with its ARID1A-negative counterpart. MATERIALS AND METHODS: Seventy cases of O-CCC were included in this study. Histologic grades and patterns of primary tumor, molecular marker immunohistochemistry profiles, and clinical outcomes were analyzed. RESULTS: Forty-eight (69%) O-CCCs did not express BAF250a, which were designated as "ARID1A-negative." The other 22 (31%) O-CCCs were designated as "ARID1A-positive." ARID1A-positive tumors were more likely to be histologically of high grades (41% vs. 10%, p=0.003), ERβ-positive (45% vs. 17%, p=0.011), and less likely to be HNF1β-positive (77% vs. 96%, p=0.016) and E-cadherin-positive (59% vs. 83%, p=0.028) than ARID1A-negative tumors. Patient age, parity, tumor stage were not significantly different in between the two groups. Cancer-specific survival was not significantly different either. CONCLUSION: We classified O-CCCs according to ARID1A expression status. ARID1A-positive O-CCCs exhibited distinct immunohistochemical features from ARID1A-negative tumors, suggesting a different underlying molecular event during carcinogenesis.

Susceptibility Vessel Sign for the Detection of Hyperacute MCA Occlusion: Evaluation with Susceptibility-weighted MR Imaging

PURPOSE: Susceptibility vessel sign (SVS) on gradient echo image, which is caused by MR signal loss due to arterial thrombosis, has been reported in acute middle cerebral artery (MCA) infarction. However, the reported sensitivity and diagnostic accuracy of SVS have been variable. Susceptibility-weighted imaging (SWI) is a newly developed MR sequence. Recent studies have found that SWI may be useful in the field of cerebrovascular diseases, especially for detecting the presence of prominent veins, microbleeds and the SVS. The purpose of this study was to evaluate the diagnostic values of SWI for the detection of hyperacute MCA occlusion. MATERIALS AND METHODS: Sixty-nine patients (37 males, 32 females; 46-89 years old [mean, 69.1]) with acute stroke involving the MCA territory underwent MR imaging within 6 hours after the symptom onset. MR examination included T2, FLAIR (fluid-attenuated inversion recovery), DWI, SWI, PWI (perfusion-weighted imaging), contrast-enhanced MR angiography (MRA) and contrast-enhanced T1. Of these patients, 28 patients also underwent digital subtraction angiography (DSA) within 2 hours after MR examination. Presence or absence of SVS on SWI was assessed without knowledge of clinical, DSA and other MR imaging findings. RESULTS: On MRA or DSA, 34 patients (49.3%) showed MCA occlusion. Of these patients, SVS was detected in 30 (88.2%) on SWI. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of SWI were 88.2%, 97.1%, 96.8%, 89.5% and 92.8%, respectively. CONCLUSION: SWI was sensitive, specific and accurate for the detection of hyperacute MCA occlusion.

Susceptibility weighted imaging: differentiating between calcification and hemosiderin / Imagem ponderada em suscetibilidade magnética: diferenciando calcificação de hemossiderina

Objective: To present a detailed explanation on the processing of magnetic susceptibility weighted imaging (SWI), demonstrating the effects of echo time and sensitive mask on the differentiation between calcification and hemosiderin. Materials and Methods: Computed tomography and magnetic resonance (magnitude and phase) images of six patients (age range 41– 54 years; four men) were retrospectively selected. The SWI images processing was performed using the Matlab’s own routine. Results: Four out of the six patients showed calcifications at computed tomography images and their SWI images demonstrated hyperintense signal at the calcification regions. The other patients did not show any calcifications at computed tomography, and SWI revealed the presence of hemosiderin deposits with hypointense signal. Conclusion: The selection of echo time and of the mask may change all the information on SWI images, and compromise the diagnostic reliability. Amongst the possible masks, the authors highlight that the sigmoid mask allows for contrasting calcifications and hemosiderin on a single SWI image. .

Objetivo: Expor em detalhes o processamento da imagem ponderada em suscetibilidade magnética (susceptibility weighted imaging – SWI), destacando o efeito da escolha do tempo de eco e da máscara sensível à diferenciação de calcificação e hemossiderina simultaneamente. Materiais e Métodos: Imagens de tomografia computadorizada e por ressonância magnética (magnitude e fase) foram selecionadas, retrospectivamente, de seis pacientes (idades entre 41 e 54 anos; quatro homens). O processamento das imagens SWI foi realizado em rotina própria no programa Matlab. Resultados: Dos seis pacientes estudados, quatro apresentaram calcificações nas imagens de tomografia computadorizada. Nestes, as imagens SWI mostraram sinal hiperintenso para as regiões de calcificações. Os outros dois pacientes não apresentaram calcificações nas imagens de tomografia computadorizada e apresentaram depósito de hemossiderina com sinal hipointenso na imagem SWI. Conclusão: A escolha do tempo de eco e da máscara pode alterar toda a informação da imagem SWI e comprometer a confiabilidade diagnóstica. Dentre as possíveis máscaras, destacamos que a máscara sigmoide permite contrastar calcificação e hemossiderina em uma única imagem SWI. .

Associated Brain Parenchymal Abnormalities in Developmental Venous Anomalies: Evaluation with Susceptibility-weighted MR Imaging

PURPOSE: The purpose of this study was to evaluate the associated brain parenchymal abnormalities of developmental venous anomalies (DVA) with susceptibility-weighted image (SWI). MATERIALS AND METHODS: Between January 2012 and June 2013, 2356 patients underwent brain MR examinations with contrast enhancement. We retrospectively reviewed their MR examinations and data were collected as per the following criteria: incidence, locations, and associated parenchymal signal abnormalities of DVAs on T2-weighted image, fluid-attenuated inversion recovery (FLAIR), and SWI. Contrast enhanced T1-weighted image was used to diagnose DVA. RESULTS: Of the 2356 patients examined, 57 DVAs were detected in 57 patients (2.4%); 47 (82.4%) were in either lobe of the supratentorial brain, 9 (15.7%) were in the cerebellum, and 1 (1.7%) was in the pons. Of the 57 DVAs identified, 20 (35.1%) had associated parenchymal abnormalities in the drainage area. Among the 20 DVAs which had associated parenchymal abnormalities, 13 showed hemorrhagic foci on SWI, and 7 demonstrated only increased parenchymal signal abnormalities on T2-weighted and FLAIR images. In 5 of the 13 patients (38.5%) who had hemorrhagic foci, the hemorrhagic lesions were demonstrated only on SWI. CONCLUSION: The overall incidence of DVAs was 2.4%. Parenchymal abnormalities were associated with DVAs in 35.1% of the cases. On SWI, hemorrhage was detected in 22.8% of DVAs. Thus, we conclude that SWI might give a potential for understanding of the pathophysiology of parenchymal abnormalities in DVAs.

Insights into brain development and disease from neurogenetic analyses in Drosophila melanogaster.

Groundbreaking work by Obaid Siddiqi has contributed to the powerful genetic toolkit that is now available for studying the nervous system of Drosophila. Studies carried out in this powerful neurogenetic model system during the last decade now provide insight into the molecular mechanisms that operate in neural stem cells during normal brain development and during abnormal brain tumorigenesis. These studies also provide strong support for the notion that conserved molecular genetic programs act in brain development and disease in insects and mammals including humans.

Diagnosis of metastases encephaloma by using susceptibility weighted imaging and contrast-enhanced T1-weighted imaging of MR before and after radiotherapy / 实用放射学杂志

Objective To evaluate the value of susceptibility-weighted imaging (SWI)sequence in the diagnosis of metastatic en-cephaloma pre and after radiotherapy by comparing the appearance of the SWI and contrast-enhanced T1-weighted imaging(T1 WI). Methods Thirty-eight lung cancer patients with brain metastases underwent SWI and contrast-enhanced T1-weighted imaging re-spectively before and 2-3 months after radiotherapy.Evaluated the two methods by score(the score ranged from 0-3,0 represen-ted no showing,1 represented not showing clearly,2 represented could judging,3 represented showing obviously).Results Before radiotherapy,SWI detected 1 61 lesions of metastases and could obviously show tumor vascular in brain metastases (mean score 2.73±0.05).Contrast-enhanced T1 WI detected 1 61 lesions(mean score 1.93±0.04 ).SWI showed significantly higher score than enhanced T1 WI(P <0.05)through paired sample t test.After radiotherapy,SWI found 98 lesions (mean score 1.47±0.1 1 )and en-hanced T1 WI found 140 lesions (mean score 1.80±0.07),enhanced T1 WI had significantly higher score than SWI(P <0.05).Con-clusion SWI is superior to contrast-enhanced T1 WI to show the metastases before radiotherapy and can show tumor vascular in brain metastases obviously.SWI is inferior to enhanced T1 WI after radiotherapy.It has some value and may provide a new method for evaluating effects of radiotherapy.

Susceptibility-Weighted MR Imaging for the Detection of Developmental Venous Anomaly: Comparison with T2 and FLAIR Imaging

PURPOSE: We evaluated the diagnostic value of susceptibility-weighted imaging (SWI) for the detection of developmental venous anomaly (DVA). MATERIALS AND METHODS: Retrospective review of 1068 brain MR examinations found 28 DVAs in 28 patients (2.6%) on contrast-enhanced T1-weighted images. SWI, T2, and FLAIR images of 28 patients with DVA and 28 sex- and age-matched control patients without DVA were analyzed by blinded readers on each type of sequences. All images were independently reviewed by two radiologists who were blinded to other MR imaging finding. In cases of discrepancy, two reviewers reached a consensus later. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of each MR sequence for the detection of DVA were determined. Statistical analysis was performed by using the Mcnemar test. The significance level was p < 0.05. RESULTS: The sensitivity, specificity, PPV, and NPV of SWI for the detection of DVA were 85.7%, 92.9%, 92.3%, and 86.7%, respectively. T2 and FLAIR images showed sensitivity of 35.7% and 35.7%, specificity of 92.9% and 96.4%, PPV of 83.3% and 90.9%, and NPV of 59.1% and 60.0%, respectively. On SWI, the sensitivity and NPV for the detection of DVAs were significantly higher than those of T2 and FLAIR images (p < 0.05). CONCLUSION: SWI was sensitive and specific for the detection of DVA.

Saccadic Palsy after Cardiac Surgery: Serial Neuroimaging Findings during a 6-Year Follow-Up

BACKGROUND: Patients who develop horizontal and vertical saccadic palsy after cardiac surgery have rarely been described. Although most such patients exhibit distinct neurological deficits, their brain MRI findings are almost normal. In addition, functional neuroimaging of such patients has never been reported. CASE REPORT: A 43-year-old woman with dysarthria, dysphagia, and horizontal and vertical saccadic palsy after cardiac surgery was followed up for about 6 years; serial brain MRIs has been performed during this period, including susceptibility-weighted imaging (SWI) and [18F]-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET). Multiple microbleeds in the cerebral cortex, cerebellum, and brainstem, and glucose hypometabolism in the brainstem, cerebellum, and multiple cortical areas. CONCLUSIONS: To the best of our knowledge, this is the first reported case of saccadic palsy after cardiac surgery with serial SWI and [18F]-FDG-PET performed to explore the possible cerebral lesions.

Clinical Utility of Prominent Hypointense Signals in the Draining Veins on Susceptibility-Weighted Imaging in Acute Cerebral Infarct: As a Marker of Penumbra and a Predictor of Prognosis

PURPOSE: A relative increase in deoxyhemoglobin levels in hypoperfused tissue can cause prominent hypointense signals in the draining veins (PHSV) within areas of impaired perfusion in susceptibility-weighted imaging (SWI). The purpose of this study is to evaluate the usefulness of SWI in patients with acute cerebral infarction by evaluating PHSV within areas of impaired perfusion and to investigate the usefulness of PHSV in predicting prognosis of cerebral infarction. MATERIALS AND METHODS: In 18 patients with acute cerebral infarction who underwent brain MRI with diffusion-weighted imaging and SWI and follow-up brain MRI or CT, we reviewed the presence and location of the PHSV within and adjacent to areas of cerebral infarction qualitatively and measured the signal intensity difference ratio of PHSVs to contralateral normal appearing cortical veins quantitatively on SWI. The relationship between the presence of the PHSV and the change in the extent of infarction in follow-up images was analyzed. RESULTS: Of the 18 patients, 10 patients showed progression of the infarction, and 8 patients showed little change on follow-up imaging. On SWI, of the 10 patients with progression 9 patients showed peripheral PHSV and the newly developed infarctions corresponded well to area with peripheral PHSV on initial SWI. Only one patient without peripheral PHSV showed progression of the infarct. The patients with infarction progression revealed significantly higher presence of peripheral PHSV (p=0.0001) and higher mean signal intensity difference ratio (p=0.006) comparing to the patients with little change. CONCLUSION: SWI can demonstrate a peripheral PHSV as a marker of penumbra and with this finding we can predict the prognosis of acute infarction. The signal intensity difference of PHSV to brain tissue on SWI can be used in predicting prognosis of acute cerebral infarction.

Diagnostic value of magnetic susceptibility weighted imaging in diffuse axonal injury / 中华放射学杂志

Objective To study the diagnostic value of susceptibility weighted imaging (SWI) in diffuse axonal injury (DAI) and investigate the relationship between SWI and clinical prognosis. MethodsTwenty patients (15 males and 5 females) with DAI were included in this study. Routine sequences (T1WI, T2WI and FLAIR) and SWI were performed on a 3.0 T MRI scanner. There were 8 cases whose Glasgow score scale (GCS) ranged from 3.0 to 5.0, 4 cases from 6.0 to 8.0 and 8 from 9.0 to 12.0. The interval time between injury and examination were from 3 hours to 20 days. The number and volume of lesions observed on SWI and routine sequence were compared using Mann-Whitney U-test and paired t-test. Pearson correlation was used to analyze the relationship between the number and volume of all lesions and GCS. Results The lesions showed punctate, beaded, patchy and cord-like hypointense signal with various size on SWI (lesion diameter <2.0 cm). Distribution of lesions was multifocal with clear boundary. Routine MRI scan found a total of 78 lesions, while SWI sequence detected 424 lesions. The number of the lesions found on SWI was more than that on conventional MRI (U=-15.447,P＜0.01). The total volume of the lesions measured on routine MRI and SWI were 19 340 mm3 and 38 042 mm3, respectively. The total volume measured on SWI was more than that on routine MR (t=5.870,P＜0.01). The number and volume of all lesions were negatively correlated with GCS (r=-0.802, -0.767, P＜0.01). Conclusion SWI sequence could find more bleeding lesions than the routine MRI sequences. The number and the volume of the lesions were closely related to GCS. SWI showed high value in the diagnosis and prediction of the prognosis of DAI.

Normal Adult Hippocampal Neurogenesis in SRG3-overexpressing Transgenic Mice

SRG3 (SWI3-related gene) is a core subunit of mouse SWI/SNF complex and is known to play a critical role in stabilizing the SWI/SNF complex by attenuating its proteasomal degradation. SWI/SNF chromatin remodeling complex is reported to act as an important endogenous regulator in the proliferation and differentiation of mammalian neural stem cells. Because limited expression of SRG3 occurs in the brain and thymus during mouse embryogenesis, it was hypothesized that the altered SRG3 expression level might affect the process of adult hippocampal neurogenesis. Due to the embryonic lethality of homozygous knockout mice, this study focuses on dissecting the effect of overexpressed SRG3 on adult hippocampal neurogenesis. The BrdU incorporation assay, immunostaing with neuronal markers for each differentiation stage, and imunoblotting analysis with intracellular molecules involved in survival in adult hippocampal neurogenesis found no alteration, suggesting that the overexpression of SRG3 protein in mature neurons had no effect on the entire process of adult hippocampal neurogenesis including proliferation, differentiation, and survival.

Clinical application MR susceptibility weighted imaging(SWI) in brain diseases / 重庆医科大学学报

Objective:To study the clinical value of susceptibility weighted imaging(SWI)in brain diseases.Methods:37 cases with blood vessel pathological change of brain diseases were collected and analyzed,including 8 example of angioma cavernosum,10 cerebral infarction,15 brain tumor,2 venous malformation and 2 venous sinus thrombus.Conventional T1WI,T2WI,DWI,the SWI and enhanced T1WI,MRA images were performed to compare the superiority of the SWI images to the others in demonstrating the small hemorrhagic focuses,the small vein,hemosiderin,calcification and other paramagnetic materials.Results:SWI could distinguish the hemorrhage from the blood vessel and discover the smaller hemorrhagic focuses of the angioma cavernosum.It could discover more tiny veins adjacent to the dilated draining vein.SWI could detect small hemorrhages in acute cerebral infarction and small draining veins in brain tumor.And draining veins in deep part and expanded rete venosum in the surfaces of brains could be obviously demonstrated when sinus venosus thrombus occurred.Conclusion:SWI is a new pulse sequence that can demonstrate the abnormal low current capacity blood vessels,the structure of small vein,the tiny hemorrhages as well as ferrugination and calcium deposition sensitively.So it can be applied in the diagnosis and antidiastole of the central nervous system diseases as an important supplement to the MRI conventional sequences.