Tailoring angle dependent ferroelectricity in nanoribbons of group-IV monochalcogenides.

Ferroelectricity is significant in low dimensional structures due to the potential applications in multifunctional nanodevices. In this work, the tailoring angle dependent ferroelectricity is systematically investigated for the nanoribbons and nanowires of puckered group-IV monochalcogenides MX (M =Ge,Sn; X =S,Se). Based on first-principles calculations, it is found that the ferroelectricity of nanoribbon and nanowire strongly depends on the tailoring angle. Firstly, the critical width for the bare nanoribbon of group-IV monochalcogenide is obtained and discussed. As the nanowires are concerned, the ferroelectricity will disappear when the tailoring angle becomes small. At last, H-passivation on the edge and the strain engineering are employed to improve the ferroelectricity of nanoribbon, and it is obtained that H-passivation is beneficial to the enhancement of polarization for nanoribbons tailored near the armchair direction, while the polarization of nanoribbons tailored along the diagonal direction will decrease when the edges are passivated with H atoms, and the tensile strain along the length direction always favors the improvement of ferroelectricity of the considered nanoribbons. Therefore, tailoring angle has great influence on the ferroelectricity of nanoribbons and nanowires, which may be used as an effective way to tune the ferroelectricity and further the electronic structures of nanostructures in the field of nanoelectronics.

Coexistence of polar distortion and conduction in doped 2D group-IV ferroelectrics: SiGe, SiSn, and GeSn.

Since the concept of ferroelectric metal predicted in the 1960s has been experimentally realized in the bulk Weyl semimetal WTe2 [Sharma et al 2019 Sci. Adv. 5, eaax5080], it is significant to find the ultrathin polar metal or ferroelectric metal due to the demand of miniature of electronic nanodevices. Here, 2D buckled monolayers composed of group-IV elements such as SiGe, SiSn, and GeSn are selected as prototype. Then, the stability of 2D ferroelectricity in the above monolayers are confirmed based on the results of first-principles calculations. Most interesting, a robustly metallic polar state has been found in the above 2D ferrolectrics under both the electron doping and hole doping, and the polar distortion becomes even more remarkable when the electrons are doped as compared with the undoped system. Thus, the coexistence of polar state and conduction is theoretically verified in the doped group-IV monolayers. We hope the 2D ferroelectric materials can be used as a starting point to look for the polar metals with atomic thickness, and further broaden their applications in 2D electronics or spintronics in the future.

Contribution of combined intraoperative electrophysiological investigation with 3-T intraoperative MRI for awake cerebral glioma surgery: comprehensive review of the clinical implications and radiological outcomes.

OBJECTIVE: This study aimed to assess the clinical efficiency of combined awake craniotomy with 3-T intraoperative MRI (iMRI)-guided resection of gliomas adjacent to eloquent cortex performed at a single center. It also sought to explore the contribution of iMRI to surgeons' learning process of maximal safe resection of gliomas. METHODS: All patients who underwent an awake craniotomy and iMRI for resection of eloquent area glioma during the 53 months between January 2011 and June 2015 were included. The cases were analyzed for short- and long-term neurological outcome, progression-free survival (PFS), overall survival (OS), and extent of resection (EOR). The learning curve was assessed after dividing the cohort into Group A (first 27 months) and Group B (last 26 months). Statistical analyses included univariate logistic regression analysis on clinical and radiological variables. Kaplan-Meier and Cox regression models were used for further analysis of OS and PFS. A p value < 0.05 was considered statistically significant. RESULTS: One hundred six patients were included in the study. Over an average follow-up period of 24.8 months, short- and long-term worsening of the neurological function was noted in 48 (46.2%) and 9 (8.7%) cases, respectively. The median and mean EOR were 100% and 92%, respectively, and complete radiographic resection was achieved in 64 (60.4%) patients. The rate of gross-total resection (GTR) in the patients with low-grade glioma (89.06% ± 19.6%) was significantly lower than that in patients with high-grade glioma (96.4% ± 9.1%) (p = 0.026). Thirty (28.3%) patients underwent further resection after initial iMRI scanning, with a 10.1% increase of the mean EOR. Multivariate Cox proportional hazards modeling demonstrated that the final EOR was a significant predictor of PFS (HR 0.225, 95% CI 0.070-0.723, p = 0.012). For patients with high-grade glioma, the GTR (p = 0.033), the presence of short-term motor deficit (p = 0.027), and the WHO grade (p = 0.005) were independent prognostic factors of OS. Performing further resection after the iMRI (p = 0.083) and achieving GTR (p = 0.05) demonstrated a PFS benefit trend for the patients affected by a low-grade glioma. Over time, the rate of performing further resection after an iMRI decreased by 26.1% (p = 0.005). A nonsignificant decrease in the rate of short-term (p = 0.101) and long-term (p = 0.132) neurological deficits was equally noted. CONCLUSIONS: Combined awake craniotomy and iMRI is a safe and efficient technique allowing maximal safe resection of eloquent area gliomas with possible subsequent OS and PFS benefits. Although there is a learning curve for applying this technique, it can also improve the surgeon's ability in eloquent glioma surgery.

Intraoperative Multi-Information-Guided Resection of Dominant-Sided Insular Gliomas in a 3-T Intraoperative Magnetic Resonance Imaging Integrated Neurosurgical Suite.

OBJECTIVE: To evaluate the clinical application of 3-T intraoperative magnetic resonance imaging (iMRI), awake craniotomy, multimodal functional mapping, and intraoperative neurophysiologic monitoring (IONM) for resection of dominant-sided insular gliomas. METHODS: From March 2011 to June 2013, 30 gliomas involving the dominant insular lobe were resected in the IMRIS 3.0-T iMRI integrated neurosurgical suite. For 20 patients, awake craniotomy with cortical electrical stimulation mapping was performed to locate the language areas. For 10 patients who were not suitable for awake surgery, general anesthesia and functional navigation were performed. Diffusion tensor imaging tractography-based navigation, continuous motor evoked potential monitoring, and subcortical electrical stimulation mapping were applied to localize and monitor the motor pathway in all cases. iMRI was used to assess the extent of resection. The results of intraoperative imaging, IONM, and the surgical consequences were analyzed. RESULTS: Intraoperative imaging revealed residual tumor in 26 cases and led to further resection in 9 cases. As a result, the median extent of resection was increased from 90% to 93% (P = 0.008) in all cases, and from 88% to 92% (P = 0.018) in low-grade gliomas. The use of iMRI also resulted in an increase in the percentage of gross and near total resection from 53% to 77% (P = 0.016). The rates of permanent language and motor deficits resulting from tumor removal were 11% and 7.1%, respectively. CONCLUSIONS: The combination of iMRI, awake craniotomy, multimodal brain mapping, and IONM tailored for each patient permits the maximal safe resection of dominant-sided insular glioma.

Metabolic approach for tumor delineation in glioma surgery: 3D MR spectroscopy image-guided resection.

OBJECT The extent of resection is one of the most essential factors that influence the outcomes of glioma resection. However, conventional structural imaging has failed to accurately delineate glioma margins because of tumor cell infiltration. Three-dimensional proton MR spectroscopy ((1)H-MRS) can provide metabolic information and has been used in preoperative tumor differentiation, grading, and radiotherapy planning. Resection based on glioma metabolism information may provide for a more extensive resection and yield better outcomes for glioma patients. In this study, the authors attempt to integrate 3D (1)H-MRS into neuronavigation and assess the feasibility and validity of metabolically based glioma resection. METHODS Choline (Cho)-N-acetylaspartate (NAA) index (CNI) maps were calculated and integrated into neuronavigation. The CNI thresholds were quantitatively analyzed and compared with structural MRI studies. Glioma resections were performed under 3D (1)H-MRS guidance. Volumetric analyses were performed for metabolic and structural images from a low-grade glioma (LGG) group and high-grade glioma (HGG) group. Magnetic resonance imaging and neurological assessments were performed immediately after surgery and 1 year after tumor resection. RESULTS Fifteen eligible patients with primary cerebral gliomas were included in this study. Three-dimensional (1)H-MRS maps were successfully coregistered with structural images and integrated into navigational system. Volumetric analyses showed that the differences between the metabolic volumes with different CNI thresholds were statistically significant (p < 0.05). For the LGG group, the differences between the structural and the metabolic volumes with CNI thresholds of 0.5 and 1.5 were statistically significant (p = 0.0005 and 0.0129, respectively). For the HGG group, the differences between the structural and metabolic volumes with CNI thresholds of 0.5 and 1.0 were statistically significant (p = 0.0027 and 0.0497, respectively). All patients showed no tumor progression at the 1-year follow-up. CONCLUSIONS This study integrated 3D MRS maps and intraoperative navigation for glioma margin delineation. Optimum CNI thresholds were applied for both LGGs and HGGs to achieve resection. The results indicated that 3D (1)H-MRS can be integrated with structural imaging to provide better outcomes for glioma resection.

Gene mutation profiling of primary glioblastoma through multiple tumor biopsy guided by 1H-magnetic resonance spectroscopy.

Genetic mutation has served as the biomarkers for the diagnosis and treatment of glioblastoma multiforme (GBM). However, intra-tumor heterogeneity may interfere with personalized treatment strategies based on mutation analysis. This study aimed to characterize somatic mutation profiling of GBM. We collected 33 samples from 7 patients with the primary GBM associated with different Choline (Cho) to N-acetylaspartate (NAA) index (CNI) through the frameless proton magnetic resonance spectroscopy (1H-MRS) guided biopsies and investigated multiple somatic mutations profiling using the AmpliSeq cancer hotspot panel V2. We identified 53 missense or nonsense mutations in 27 genes including some novel mutations such as APC and IDH2. The mutations in EGFR, TP53, PTEN, PIK3CA genes were presented with different frequency and the majority of the mutated gene was only shared by 1-2 samples from one patient. Moreover, we found the association of CNI with histological grade, but there was no significant change of CNI in the presence of TP53, EGFR and PTEN mutations. These data suggest that gene mutations constitute a heterogeneous marker for primary GBM which may be independent of intra-tumor morphological phenotypes of GBM; therefore, gene mutation markers could not be determined from a small number of needle biopsies or only confined to the high-grade region.

Localizing hand motor area using resting-state fMRI: validated with direct cortical stimulation.

BACKGROUND: Resting-state functional magnetic resonance imaging (R-fMRI) is a promising tool in clinical application, especially in presurgical mapping for neurosurgery. This study aimed to investigate the sensitivity and specificity of R-fMRI in the localization of hand motor area in patients with brain tumors validated by direct cortical stimulation (DCS). We also compared this technique to task-based blood oxygenation level-dependent (BOLD) fMRI (T-fMRI). METHODS: R-fMRI and T-fMRI were acquired from 17 patients with brain tumors. The cortex sites of the hand motor area were recorded by DCS. Site-by-site comparisons between R-fMRI/T-fMRI and DCS were performed to calculate R-fMRI and T-fMRI sensitivity and specificity using DCS as a "gold standard". R-fMRI and T-fMRI performances were compared statistically RESULTS: A total of 609 cortex sites were tested with DCS and compared with R-fMRI findings in 17 patients. For hand motor area localization, R-fMRI sensitivity and specificity were 90.91 and 89.41 %, respectively. Given that two subjects could not comply with T-fMRI, 520 DCS sites were compared with T-fMRI findings in 15 patients. The sensitivity and specificity of T-fMRI were 78.57 and 84.76 %, respectively. In the 15 patients who successfully underwent both R-fMRI and T-fMRI, there was no statistical difference in sensitivity or specificity between the two methods (p = 0.3198 and p = 0.1431, respectively) CONCLUSIONS: R-fMRI sensitivity and specificity are high for localizing hand motor area and even equivalent or slightly higher compared with T-fMRI. Given its convenience for patients, R-fMRI is a promising substitute for T-fMRI for presurgical mapping.

Clinical experience of 3T intraoperative magnetic resonance imaging integrated neurosurgical suite in Shanghai Huashan Hospital.

BACKGROUND: Intraoperative magnetic resonance imaging (iMRI) dates back to the 1990s and has been successfully applied in neurosurgery but they were low-field iMRI (< 1.0T). This paper reports the clinical experience with a 3T iMRI-integrated neurosurgical suite in Huashan Hospital, Shanghai, China. METHODS: From September 2010 through March 2012, 373 consecutive patients underwent neurological surgery under guidance with 3T iMRI. A retrospective analysis was conducted regarding clinical efficiency. RESULTS: All surgery in the 373 patients was safe. The ratio of gross total resection for cerebral gliomas (n = 161) was increased from 55.90% to 87.58%. The ratio of benefit in extent of resection was 39.13%. One hundred and fifty eight of the 161 glioma patients accomplished follow-up at 3 months postoperatively. Twenty of 161 patients (12.42%) suffered from early motor deficit after surgery. Late motor deficit was however observed in five of 158 patients (3.16%). Twenty-one of 161 patients (13.04%) had early speech deficit and late speech deficit was only observed in six of 158 patients (3.80%). The ratio of gross total resection for pituitary adenomas (n = 49) was increased from 77.55% to 85.71%. The ratio of benefit in extent of resection was 10.2%. There were no iMRI-related adverse events even for patients who underwent awake craniotomy. CONCLUSION: The 3T iMRI integrated neurosurgical suite provides high-quality intraoperative structural and functional imaging for real-time tumor resection control and accurate functional preservation, resulting in an improvement in maximal safe brain surgery.

Clinical application of motor pathway mapping using diffusion tensor imaging tractography and intraoperative direct subcortical stimulation in cerebral glioma surgery: a prospective cohort study.

BACKGROUND: Glioma surgery in eloquent areas remains a challenge because of the risk of postoperative motor deficits. OBJECTIVE: To prospectively evaluate the efficiency of using a combination of diffusion tensor imaging (DTI) tractography functional neuronavigation and direct subcortical stimulation (DsCS) to yield a maximally safe resection of cerebral glioma in eloquent areas. METHODS: A prospective cohort study was conducted in 58 subjects with an initial diagnosis of primary cerebral glioma within or adjacent to the pyramidal tract (PT). The white matter beneath the resection cavity was stimulated along the PT, which was visualized with DTI tractography. The intercept between the PT border and DsCS site was measured. The sensitivity and specificity of DTI tractography for PT mapping were evaluated. The efficiency of the combined use of both techniques on motor function preservation was assessed. RESULTS: Postoperative analysis showed gross total resection in 40 patients (69.0%). Seventeen patients (29.3%) experienced postoperative worsening; 1-month motor deficit was observed in 6 subjects (10.3%). DsCS verified a high concordance rate with DTI tractography for PT mapping. The sensitivity and specificity of DTI were 92.6% and 93.2%, respectively. The intercepts between positive DsCS sites and imaged PTs were 2.0 to 14.7 mm (5.2 ± 2.2 mm). The 6-month Karnofsky performance scale scores in 50 postoperative subjects were significantly increased compared with their preoperative scores. CONCLUSION: DTI tractography is effective but not completely reliable in delineating the descending motor pathways. Integration of DTI and DsCS favors patient-specific surgery for cerebral glioma in eloquent areas.

"Awake" intraoperative functional MRI (ai-fMRI) for mapping the eloquent cortex: Is it possible in awake craniotomy?

As a promising noninvasive imaging technique, functional MRI (fMRI) has been extensively adopted as a functional localization procedure for surgical planning. However, the information provided by preoperative fMRI (pre-fMRI) is hampered by the brain deformation that is secondary to surgical procedures. Therefore, intraoperative fMRI (i-fMRI) becomes a potential alternative that can compensate for brain shifts by updating the functional localization information during craniotomy. However, previous i-fMRI studies required that patients be under general anesthesia, preventing the wider application of such a technique as the patients cannot perform tasks unless they are awake. In this study, we propose a new technique that combines awake surgery and i-fMRI, named "awake" i-fMRI (ai-fMRI). We introduced ai-fMRI to the real-time localization of sensorimotor areas during awake craniotomy in seven patients. The results showed that ai-fMRI could successfully detect activations in the bilateral primary sensorimotor areas and supplementary motor areas for all patients, indicating the feasibility of this technique in eloquent area localization. The reliability of ai-fMRI was further validated using intraoperative stimulation mapping (ISM) in two of the seven patients. Comparisons between the pre-fMRI-derived localization result and the ai-fMRI derived result showed that the former was subject to a heavy brain shift and led to incorrect localization, while the latter solved that problem. Additionally, the approaches for the acquisition and processing of the ai-fMRI data were fully illustrated and described. Some practical issues on employing ai-fMRI in awake craniotomy were systemically discussed, and guidelines were provided.

[Preliminary application of 3.0 T intraoperative magnetic resonance imaging neuronavigation system in China].

OBJECTIVE: To report the preliminary experience in clinical application of 3.0 T intraoperative magnetic resonance imaging (iMRI) neuronavigation system in China. METHODS: From September 2010 to March 2011, a consecutive series of 122 patients with intracranial lesions underwent operations in guidance with 3.0 T iMRI. A retrospective analysis was conducted regarding clinical efficiency. RESULTS: Among 122 procedures, the numbers of intraoperative scanning were 2 - 4 times with an average of 2.6. The qualities of images were excellent. Due to the discovery and further possibility of resection of residual tumors, the ratio of gross total resection was increased from 71.7% to 90.0% in cerebral gliomas (n = 60), while from 75.9% to 93.1% in macroadenomas (n = 29). There were 6.7% of all patients occurred postoperative paralysis, but only 3.3% of patients had persistent paralysis at 1 - 2 months follow-up. There was no iMRI-related adverse event occurred. During the same period, more than 2500 patients underwent diagnostic MRI scanning. CONCLUSIONS: 3.0 T iMRI neuronavigation system provides high-quality intraoperative structural, functional and metabolic images for real time tumor resection control and accurate functional preservation, resulting in an improvement in maximal safe brain surgery. The system is cost-effective.

[Awake craniotomy and intraoperative language cortical mapping for eloquent cerebral glioma resection: preliminary clinical practice in 3.0 T intraoperative magnetic resonance imaging integrated surgical suite].

OBJECTIVES: To evaluate preliminary clinical experience for combining awake craniotomy and intraoperative language brain mapping within the integrated 3.0 T intraoperative magnetic resonance imaging (iMRI) suite. METHODS: From December 2010 to April 2011, 11 right hand-dominant patients with left glioma were involved in, or adjacent to, eloquent cortex was carried out awake craniotomies with cortical stimulation within an integrated 3.0 T iMRI suite. Aphasia battery of Chinese was used to test the language function before the operation. During the procedure, after the occipital, temporal, and supraorbital nerves were blocked by the anesthesiologists, the head was fixed with a custom high-field MRI-compatible head holder. The skull and dura was opened as usual and language brain mapping was then performed. Language testing followed a set protocol: counting numbers from 1 to 50, naming objects, reading single words. Resection of the tumor was guided by neuronavigation system and continued until eloquent areas were encountered or the margin of assessment was reached. An interdissection MRI was acquired to evaluate the glioma removal in a movable MRI scanner after minimal draping. Meanwhile, adverse effects caused by electrical stimulation and iMRI were recorded. The follow-up speech tests were assessed on 7th day and 1 month at least after the operation. RESULTS: The combined use of 3.0 T iMRI and awake craniotomy was performed safely in all patients. No adverse effects were reported. The duration of surgery was prolonged by 2 to 4 h. The patients' perception of iMRI during surgery was favorable. First-look MRI studies led to further resection attempts in 6/11 cases as well as a 3/11 increase in the number of gross-total resections. One week after surgery, baseline language function worsened in 4 cases. However, no patients had a persistent language deficit one month after surgery. CONCLUSIONS: Awake craniotomy and direct cortical electrical stimulation can be performed safely and effectively within a 3.0 T iMRI suite. The combination of high-field iMRI and awake craniotomy may facilitate safe removal of eloquent glioma.

Current status of cerebral glioma surgery in China.

The treatment of gliomas is highly individualized. Surgery for gliomas is essentially for histological diagnosis, to alleviate mass effect, and most importantly, to favor longer survival expectancy. During the past two decades, many surgical techniques and adjuvants have been applied to glioma surgery in China, which lead to a rapid development in the field of cerebral glioma surgery. This article broadly and critically reviewed the existing studies on cerebral glioma surgery and to portrait the current status of glioma surgery in China. A literature search was conducted covering major innovative surgical techniques and adjuvants for glioma surgery in China. The following databases were searched: the Pubmed (January 1995 to date); China Knowledge Resource Integrated Database (January 1995 to date) and VIP Database for Chinese Technical Periodicals (January 1995 to date). A selection criterion was established to exclude duplicates and irrelevant studies. The outcome measures were extracted from included studies. A total of 3307 articles were initially searched. After excluded by abstracts and full texts, 69 studies conducted in the mainland of China were included and went through further analysis. The philosophy of surgical strategies for cerebral gliomas in China is undergoing tremendous change. Nowadays Chinese neurosurgeons pay more attention to the postoperative neurofunctional status of the patients. The aim of the glioma surgery is not only the more extensive tumor resection but also the maximal safety of intervention. The well balance of longer overall survival and higher quality of life should be judged with respect to each individual patient.

Transsphenoidal pituitary macroadenomas resection guided by PoleStar N20 low-field intraoperative magnetic resonance imaging: comparison with early postoperative high-field magnetic resonance imaging.

OBJECTIVE: To evaluate the applicability of low-field intraoperative magnetic resonance imaging (iMRI) during transsphenoidal surgery of pituitary macroadenomas. METHODS: Fifty-five transsphenoidal surgeries were performed for macroadenomas (modified Hardy's Grade II-IV) resections. All of the surgical processes were guided by real-time updated contrast T1-weighted coronal and sagittal images, which were acquired with 0.15 Tesla PoleStar N20 iMRI (Medtronic Navigation, Louisville, CO). The definitive benefits as well as major drawbacks of low-field iMRI in transsphenoidal surgery were assessed with respect to intraoperative imaging, tumor resection control, comparison with early postoperative high-field magnetic resonance imaging, and follow-up outcomes. RESULTS: Intraoperative imaging revealed residual tumor and guided extended tumor resection in 17 of 55 cases. As a result, the percentage of gross total removal of macroadenomas increased from 58.2% to 83.6%. The accuracy of imaging evaluation of low-field iMRI was 81.8%, compared with early postoperative high-field MRI (Correlation coefficient, 0.677; P < 0.001). A significantly lower accuracy was identified with low-field iMRI in 6 cases with cavernous sinus invasion (33.3%) in contrast to the 87.8% found with other sites (Fisher's exact test, P < 0.001). CONCLUSION: The PoleStar N20 low-field iMRI navigation system is a promising tool for safe, minimally invasive, endonasal, transsphenoidal pituitary macroadenomas resection. It enables neurosurgeons to control the extent of tumor resection, particularly for suprasellar tumors, ensuring surgical accuracy and safety, and leading to a decreased likelihood of repeat surgeries. However, this technology is still not satisfying in estimating the amount of the parasellar residual tumor invading into cavernous sinus, given the false or uncertain images generated by low-field iMRI in this region, which are difficult to discriminate between tumor remnant and blood within the venous sinus.

Colorectal cancer cell detection by 5-aminolaevulinic acid-loaded chitosan nano-particles.

Colorectal cancer is one of the leading causes of malignant death in Taiwan because it often remains undetected until later stages of the disease. In this study, we designed an oral form nano-particle to encapsulate 5-aminolaevulinic acid (5-ALA) to improve the detection of colorectal cancer cells in vivo. The nano-particle should escape from bacteria uptake in the gastrointestinal tract which seriously interferes the results of endoscopic observation. In this study, chitosan was mixed with sodium tripolyphosphate (STPP) and 5-ALA to prepare chitosan nano-particles (CN) and 5-ALA loaded chitosan nano-particles (CNA) by adding different pH values and concentrations of 5-ALA solution. The average particle size and zeta-potential of CN and CNA were measured by the Zetasizer-3000. The results revealed that particle size with different zeta-potential could be manipulated just by 5-ALA concentrations and pH values. CNA particles prepared at pH 7.4 and pH 9 of 5-ALA solutions with a concentration higher than 0.5 mg/ml showed a promising loading efficiency of up to 75% and an optimum average particle size of 100 nm. The zeta-potential for CNA was over 30 mV that kept the nano-particle stable without aggregation when stored in suspension solution. Fluorescence microscope examination showed that CNA could be engulfed by Caco-2 colon cancer cells but showed no evidence of being taken up by Escherichia coli. This result implies that CNA could exclude the influence of normal flora inside the gut and serves as an adequate tool for fluorescent endoscopic detection of colorectal cancer cells in vivo.

[High risk factors of upper gastrointestinal bleeding after neurosurgical procedures].

OBJECTIVE: To analyze high risk factors of postoperative upper gastrointestinal (GI) bleeding after neurosurgery so as to give guidance for prevention of GI bleeding. METHODS: A questionnaire was developed to investigate the medical records of 1500 patients who were hospitalized and underwent neurosurgical operations in 1997. Logistic regression analysis was made. RESULTS: 1430 valid questionnaires were obtained. Postoperative upper GI bleeding occurred in 75 patients (5.24%). The incidence of upper GI bleeding were 6.64% (54/813) in the male patients and 3.40% (21/617) in the female persons (P = 0.007); 9.88% (41/415) in those aged > 50 and 3.35% in those aged < or = 50 (P = 0.001). Glasgow Coma Score less than 10 pre- and post-operation, the incidence of upper GI bleeding was more than 17.5% (14/80, pre-operation GCS 7-10) and 20.9% (14/67, pre-operation GCS 3-6), and 20.25% (16/79, first day of post-operation GCS 7-10) and 23.75% (19/80, first day of post-operation GCS 3-6). The incidence of upper GI bleeding of the patients with intracerebral hematoma, intraventricular hemorrhage, subdural hematoma, and extradural hematoma were 15.7%, 10.0%, 6.00%, and 2.94% respectively (P = 0.02). The incidence of upper GI bleeding of the patients with tumors of fourth ventricle of cerebrum, brainstem, cerebral hemisphere, and sellar hypothalamus were 15.79% (3/19), 7.89%, 5.71%, and 3.74% respectively. In the emergent cases, the incidence of upper GI bleeding was higher in those with hypertension. The incidence of upper GI bleeding was 5.46% in the patients undergoing adrenocortical hormone treatment, significantly higher than that in those who did not receive such treatment (2.13%). CONCLUSION: Patients who are at high risk of developing postoperative upper GI bleeding including that: age greater than 50 years; male; Glasgow Coma Score less than 10 pre and post operation; The lesion was located in brain stem and forth ventricle; Hypertensive cerebral hemorrhage; Intracerebral and intraventricular hemorrhagic brain trauma; Postoperative pneumonia, brain edema, encephalic high pressure, pyogenic infection of the central nervous system and other postoperative complications. The mortality of patients with postoperative upper GI bleeding was evidently higher than that of the patients without postoperative upper GI bleeding.