ARHGEF19 interacts with BRAF to activate MAPK signaling during the tumorigenesis of non-small cell lung cancer.

Rho guanine nucleotide exchange factors (RhoGEFs) are proteins that activate Rho GTPases in response to extracellular stimuli and regulate various biologic processes. ARHGEF19, one of RhoGEFs, was reported to activate RhoA in the Wnt-PCP pathway controlling convergent extension in Xenopus gastrulation. The goal of our study was to identify the role and molecular mechanisms of ARHGEF19 in the tumorigenesis of non-small cell lung cancer (NSCLC). ARHGEF19 expression was significantly elevated in NSCLC tissues, and ARHGEF19 levels were significantly associated with lymph node status, distant metastasis and TNM stage; Patients with high ARHGEF19 levels had poor overall survival (OS) and progression-free survival (PFS). Our investigations revealed that ARHGEF19 overexpression promoted the cell proliferation, invasion and metastasis of lung cancer cells, whereas knockdown of this gene inhibited these processes. Mechanistically, ARHGEF19 activated the mitogen-activated protein kinase (MAPK) pathway in a RhoA-independent manner: ARHGEF19 interacted with BRAF and facilitated the phosphorylation of its downstream kinase MEK1/2; both the Dbl homology (DH) and Pleckstrin homology (PH) domains of ARHGEF19 were indispensable for the phosphorylation of MEK1/2. Furthermore, downregulation of miR-29b was likely responsible for the increased expression of ARHGEF19 in lung cancer tissues and, consequently, the abnormal activation of MAPK signaling. These findings suggest that ARHGEF19 upregulation, due to the low expression of miR-29 in NSCLC tissues, may play a crucial role in NSCLC tumorigenesis by activating MAPK signaling. ARHGEF19 could serve as a negative prognostic marker as well as a therapeutic target for NSCLC patients.

Nasopharyngeal carcinoma patients with retropharyngeal lymph node metastases: a minimum axial diameter of 6 mm is a more accurate prognostic predictor than 5 mm.

OBJECTIVE: The criteria for the diagnosis of metastatic retropharyngeal lymph nodes (RLNs) have not yet been resolved and are not included in the current edition of the American Joint Committee on Cancer (AJCC) staging system (seventh edition) for the staging of nasopharyngeal carcinoma (NPC). The aim of this study was to use MRI to identify an RLN size criterion that can accurately predict prognosis in patients with NPC. MATERIALS AND METHODS: Eight hundred seventeen patients with newly diagnosed localized NPC were identified. All of the patients underwent MRI before treatment with definitive radiation therapy. All the MRI studies and medical records were reviewed retrospectively. Overall survival (OS), distant metastasis-free survival (DMFS), and local relapse-free survival (LRFS) were assessed using SPSS software (version 17.0). RESULTS: RLN size cutoffs of ≥ 5 mm and of ≥ 6 mm were used. There was no significant difference in OS (p = 0.216), DMFS (p = 0.081), or LRFS (p = 0.067) in patients with RLNs ≥ 5 mm and in those with RLNs < 5 mm. When 6 mm was used as a size cutoff, significant differences in OS (p = 0.000) and DMFS (p = 0.001) were identified; there was no significant difference observed for LRFS (p = 0.380). CONCLUSION: A minimum axial RLN diameter of 6 mm was a more accurate prognostic predictor in NPC patients with RLN metastases than 5 mm.

Nasopharyngeal carcinoma with paranasal sinus invasion: the prognostic significance and the evidence-based study basis of its T-staging category according to the AJCC staging system.

BACKGROUND: To evaluate the prognostic significance of paranasal sinus invasion for patients with NPC and to provide empirical proofs for the T-staging category of paranasal sinus invasion according to the AJCC staging system for nasopharyngeal carcinoma. METHODS: The clinical records and imaging studies of 770 consecutive patients with newly diagnosed, untreated, and nondisseminated NPC were reviewed retrospectively. The overall survival, distant metastasis-free survival, and local relapse-free survival of these patients were analyzed using the Kaplan-Meier method, and the differences were compared using the log-rank test. RESULTS: The incidence of paranasal sinus invasion was 23.6%, with the rate of incidence of sphenoid sinus invasion being the highest. By multivariate analysis, paranasal sinus invasion was shown to be an independent prognostic factor for overall survival, distant metastasis-free survival, and local relapse-free survival (p < 0.05 for all). No significant differences in overall survival, distant metastasis-free survival, and local relapse-free survival were observed between patients with sphenoid sinus invasion alone and those with maxillary sinus and ethmoid sinus invasion (p = 0.87, p = 0.80, and p = 0.37, respectively). The overall survival, distant metastasis-free survival, and local relapse-free survival for patients with stage T3 disease with paranasal sinus invasion were similar to the survival rates for patients with stage T3 disease without paranasal sinus invasion (p = 0.22, p = 0.15, and p = 0.93, respectively). However, the rates of overall survival and local relapse-free survival were better for patients with stage T3 disease with paranasal sinus invasion than for patients with stage T4 disease (p < 0.01, and p = 0.03, respectively). CONCLUSIONS: Paranasal sinus invasion is an independent negative prognostic factor for NPC, regardless of which sinus is involved. Our results confirm that it is scientific and reasonable for the AJCC staging system for nasopharyngeal carcinoma to define paranasal sinus invasion as stage T3 disease.

XELOX (capecitabine plus oxaliplatin) plus bevacizumab (anti-VEGF-A antibody) with or without adoptive cell immunotherapy in the treatment of patients with previously untreated metastatic colorectal cancer: a multicenter, open-label, randomized, controlled, phase 3 trial.

Fluoropyrimidine-based combination chemotherapy plus targeted therapy is the standard initial treatment for unresectable metastatic colorectal cancer (mCRC), but the prognosis remains poor. This phase 3 trial (ClinicalTrials.gov: NCT03950154) assessed the efficacy and adverse events (AEs) of the combination of PD-1 blockade-activated DC-CIK (PD1-T) cells with XELOX plus bevacizumab as a first-line therapy in patients with mCRC. A total of 202 participants were enrolled and randomly assigned in a 1:1 ratio to receive either first-line XELOX plus bevacizumab (the control group, n = 102) or the same regimen plus autologous PD1-T cell immunotherapy (the immunotherapy group, n = 100) every 21 days for up to 6 cycles, followed by maintenance treatment with capecitabine and bevacizumab. The main endpoint of the trial was progression-free survival (PFS). The median follow-up was 19.5 months. Median PFS was 14.8 months (95% CI, 11.6-18.0) for the immunotherapy group compared with 9.9 months (8.0-11.8) for the control group (hazard ratio [HR], 0.60 [95% CI, 0.40-0.88]; p = 0.009). Median overall survival (OS) was not reached for the immunotherapy group and 25.6 months (95% CI, 18.3-32.8) for the control group (HR, 0.57 [95% CI, 0.33-0.98]; p = 0.043). Grade 3 or higher AEs occurred in 20.0% of patients in the immunotherapy group and 23.5% in the control groups, with no toxicity-associated deaths reported. The addition of PD1-T cells to first-line XELOX plus bevacizumab demonstrates significant clinical improvement of PFS and OS with well tolerability in patients with previously untreated mCRC.

[MRI analysis of paranasal sinus invasion in 182 patients with nasopharyngeal carcinoma].

OBJECTIVE: The aim of the study was to analyze the nuclear magnetic resonance image (MRI) findings for invasion of paranasal sinuses in patients with nasopharyngeal carcinoma (NPC) and to improve the understanding of its MRI diagnosis. METHODS: The MRI data of 182 patients with nasopharyngeal carcinoma and paranasal sinus invasion were retrospectively analyzed. RESULTS: One hundred and eighty-two patients developed paranasal sinus invasion, of which, the incidence of sphenoid sinus invasion was highest. The MRI findings of paranasal sinus invasion of patients with NPC were as follows: 100%, 95.6% and 56.6% patients revealed damage of sinus wall, uneven thickening of mucosa, masses of the sinus cavity connected with the primary tumor of nasopharynx, and all the lesions presented iso- or slightly hypo-intense signal on T1WI and iso- or slightly hyper-intense signal on T2WI and significantly heterogeneous enhancement after contrast administration, which were consistent with the primary tumor of the nasopharynx regarding to the signal intensity and reinforcement schedule. 77.5% patients presented massive sinus cavity effusion. T2-weighted images are excellent in differentiating high signal intensity thickened mucosa or retained secretions from relatively lower signal intensity tumor. In contrast-enhanced MRI, tumor with solid enhancement can be differentiated from thickened mucosa related to inflammation with a thin superficial enhancement. 96.5% and 94.7% patients with maxillary sinus invasion and ethmoid sinus invasion were detected with the contrast enhanced axial T1-weighted MR imaging respectively, which were higher than those with the non-enhanced axial T1 and T2 imaging (88.4% and 77.9% for maxillary sinus invasion; 65.8% and 73.7% for ethmoid sinus invasion), the differences were statistically significant (P < 0.05 for all comparison). All patients with sphenoid sinus invasion were detected with the contrast enhanced sagittal T1-weighted MR imaging. CONCLUSION: Multiplanner MR scan and enhanced scan can improve the diagnosis of invasion of paranasal sinuses in patients with NPC. The MRI findings of patients with NPC with paranasal sinus invasion include sinus wall damage; unevenly thickening mucous membrane of sinuses; tumors in sinus cavity connective with the primary tumor of nasopharynx , or with massive sinus cavity effusion. The T2-weighted sequence and contrast enhanced sequence are conducive to differential diagnosis of inflammatory changes from neoplastic tissues. The enhanced axial T1-weighted section and the enhanced sagittal T1-weighted section are most helpful to detection of maxillary sinus, ethmoid sinus invasion and sphenoid sinus invasion, respectively.

Rapamycin and trametinib: a rational combination for treatment of NSCLC.

Mammalian target of rapamycin (mTOR) is one of the most commonly activated pathways in human cancers, including lung cancer. Targeting mTOR with molecule inhibitors is considered as a useful therapeutic strategy. However, the results obtained from the clinical trials with the inhibitors so far have not met the original expectations, largely because of the drug resistance. Thus, combined or multiple drug therapy can bring about more favorable clinical outcomes. Here, we found that activation of ERK pathway was responsible for rapamycin drug resistance in non-small-cell lung cancer (NSCLC) cells. Accordingly, rapamycin-resistant NSCLC cells were more sensitive to ERK inhibitor (ERKi), trametinib, and in turn, trametinib-resistant NSCLC cells were also susceptible to rapamycin. Combining rapamycin with trametinib led to a potent synergistic antitumor efficacy, which induced G1-phase cycle arrest and apoptosis. In addition, rapamycin synergized with another ERKi, MEK162, and in turn, trametinib synergized with other mTORi, Torin1 and OSI-027. Mechanistically, rapamycin in combination with trametinib resulted in a greater decrease of phosphorylation of AKT, ERK, mTOR and 4EBP1. In xenograft mouse model, co-administration of rapamycin and trametinib caused a substantial suppression in tumor growth without obvious drug toxicity. Overall, our study identifies a reasonable combined strategy for treatment of NSCLC.

Improved energy storage performance of PbZrO3 antiferroelectric thin films crystallized by microwave radiation.

Energy storage dielectric capacitors based on a physical charge-displacement mechanism have attracted much attention due to their high power density and fast charge-discharge characteristics. How to improve the energy storage capacity of dielectric materials has become an important emerging research topic. Here, antiferroelectric PbZrO3 films were prepared by chemical solution deposition on Pt/Ti/SiO2/Si substrates and crystallized by microwave radiation. The effects of microwave radiation on the antiferroelectric properties and energy storage performance were investigated. In contrast to ordinary heating, microwave radiation can crystallize the amorphous PbZrO3 films into the perovskite phase at 750 °C in only 180 seconds. The PbZrO3 films have a highly (100)-preferred orientation and dense microstructure, which is beneficial to enhance the stability of antiferroelectric phase and the electric breakdown strength. The PbZrO3 films show a recoverable energy storage density of 14.8 J cm-3 at 740 kV cm-1, which is approximately 40% higher than that of the PbZrO3 films crystallized by ordinary heating. The results reveal that microwave radiation is an effective method to improve energy storage performance of antiferroelectric films.

Radiologic criteria of retropharyngeal lymph node metastasis in nasopharyngeal carcinoma treated with radiation therapy.

PURPOSE: To determine the appropriate radiologic criteria of metastatic retropharyngeal lymph nodes (RLNs) in patients with nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: After institutional review board approval and informed consent, 303 consecutive NPC patients treated with definitive radiation therapy were examined after completion of therapy. RLNs were classified as metastatic on the basis of the results of magnetic resonance (MR) imaging follow-up.The receiver operating characteristic curve and area under the curve were determined to assess the accuracy of different size criteria in the diagnosis of RLN metastasis. RESULTS: Initial MR images revealed 523 RLNs in 265 patients. Two hundred sixty-four (50.5%) RLNs positive for malignant involvement were confirmed in 177 patients. The remaining 259 (49.5%) nodes were classified as negative for benign process at follow-up. The minimal axial diameter was found to be more accurate than the maximal axial diameter for assessing metastatic RLNs. The most accurate size criterion of metastatic RLNs was a minimal axial diameter of 6 mm or larger, resulting in an accuracy of 87.5% (457 of 522). Central necrosis or groups of two or more of RLNs had a 100% specificity for diagnosis of RLN metastases. CONCLUSION: The radiologic criteria that should be used for assessment of RLN metastases in NPC patients are nodes with a minimal axial diameter 6 mm or larger, any node with central necrosis, groups of two or more RLNs, or any medial RLN; these criteria may be useful in tumor staging and treatment planning.

[Distributions of primary nasopharyngeal carcinoma tumor and patterns of skull base erosion detected by magnetic resonance imaging].

OBJECTIVE: To evaluate the distributions of primary nasopharyngeal carcinoma (NPC) and the patterns of skull base involvement in NPC patients using magnetic resonance imaging (MRI). METHODS: After the approval of institutional review board and informed consent, 838 consecutive newly-diagnosed and untreated NPC patients were examined by MRI. Their MR images were reviewed by two independent radiologists. RESULTS: Among all cases, the incidence rates of superior side and post-superior side involvement were 98.57% (826/838) and 98.21% (823/838) respectively. The differences were not significant between these two sides (P > 0.05). Lateral side erosion was demonstrated in 784 (93.56%) cases. Posterior side was involved in 391 (46.66%) cases. The total incidence rate of skull base involvement was 65.51% (549/838). According to the anatomic site, the pathways of skull base involvement were classified into 5 spreading routes: anterior; superior; super-lateral; super-anterior and super-posterior. According to the incidence rates and the results of chi-square test, the anatomic sites around the nasopharynx were classified into three groups of risk grades: high-risk (≥ 35%), medium-risk (≥ 5% - 35%) and low-risk (< 5%). CONCLUSION: Skull base involvement of NPC spreads stepwise from proximal site to more distal sites. The area of skull base involvement in NPC is classified into high-grade, medium-grade and lower-grade groups respectively. The high and medium-grade groups are related with T3 stage while the lower-grade group T4 stage. Thus T3 stage should be subdivided into T3a and T3b. These schemes may be useful in a more accurate NPC staging and a delineation of clinical target volume for radiotherapy in NPC patients.

Ultrahigh-Energy Storage Properties of (PbCa)ZrO3 Antiferroelectric Thin Films via Constructing a Pyrochlore Nanocrystalline Structure.

In recent years, antiferroelectric materials have been attracting considerable attention as energy storage capacitors due to their potential applications in pulsed power systems. In this work, antiferroelectric Pb0.88Ca0.12ZrO3 (PCZ) thin films were prepared via chemical solution deposition and annealed using rapid thermal annealing. The microstructures of PCZ thin films were controlled via annealing temperature, and the effects of microstructures on electric properties and energy storage performance were systematically studied. Our results indicate that PCZ thin films annealed at 550 °C crystallized into a nanocrystalline structure of the pyrochlore phase, while also displaying the highest recoverable energy density and efficiency (91.3 J/cm3 and 85.3%). We attribute the ultrahigh energy storage properties mainly to dramatic improvements in the electric breakdown strength caused by the dense nanocrystalline structure. The findings reported herein help to elucidate the relationship between energy storage performance and thin-film microstructure, thereby providing an effective way for improving the energy storage performance of antiferroelectric thin films.

[Simulation model for cucumber growth and development in sunlight greenhouse]. / æ—¥å ‰æ¸©å®¤é»„ç“œç”Ÿé•¿å‘è‚²æ¨¡æ‹Ÿæ¨¡åž‹.

The dynamic simulation of cucumber growth and development in sunlight greenhouse can provide technical support for the intelligent management of cucumber production. According to the cucumber response characteristics to light and temperature, the cucumber development module based on the algorithm of clock model was established by using data from four-stage experiment with 'Jinyou 35' as experiment variety in two years. Based on the relationship between the leaf growth and key meteorological factors (temperature and radiation), leaf area index (LAI) module was established with the accumulated product of thermal effectiveness and photosynthetically active radiation (TEP) as independent variables. The simulation module of cucumber dry matter production was established by taking into consideration the double integral of LAI and daily length in photosynthesis per unit leaf area as well as the respiratory expenditure of different organs. Combined with water content of organs, fresh weight simulation module of cucumber organs was constructed. The whole cucumber development and growth simulation model in greenhouse was built based on each sub-module. The model parameters were calibrated and determined. The results showed that root mean square error (RMSE) of simulated values and observed values of four deve-lopment stages (from transplanting date to stretch tendril, to initial flowering, to early harvested and to uprooting), was 3.9-10.5 d. The normalized root mean square error (nRMSE) was 6.5%-28.6%. The coincidence index (D) was 0.79-0.97. The relationship between LAI and TEP was the regression of 'S' type curve. The RMSE of simulated and observed LAI values was 0.19. The nRMSE was 17.2%. The D value was 0.90. The RMSE of dry weight of root, stem, leaf, flower and fruit of the simulated values and observed values were 0.39-8.94 g·m-2. The nRMSE were 10.9%-17.7%. The D values were all above 0.98. The growth and development model of cucumber could accurately simulate the key development period of cucumber, leaf area and the dry and fresh weight of various organs and quantify the growth and development of cucumber in sunlight greenhouse.

BST2 confers cisplatin resistance via NF-κB signaling in nasopharyngeal cancer.

Concurrent/adjuvant cisplatin-based chemoradiotherapy is regarded as the standard of treatment for locoregionally advanced nasopharyngeal carcinoma (NPC). However, patients who do not respond to cisplatin suffer, rather than benefit, from chemotherapy treatment. The goal of this study was to identify molecules involved in cisplatin resistance and to clarify their molecular mechanisms, which would help in the discovery of potential therapeutic targets and in developing a personalized and precise treatment approach for NPC patients. We previously generated a cisplatin-sensitive NPC cell line, S16, from CNE2 cells and found that eIF3a, ASNS and MMP19 are upregulated in S16 cells, which contributes to their cisplatin sensitivity. In this study, we found that BST2 is downregulated in cisplatin-sensitive S16 cells compared with CNE2 cells. Knockdown of BST2 in NPC cells sensitized their response to cisplatin and promoted cisplatin-induced apoptosis, whereas exogenous overexpression of BST2 increased their cisplatin resistance and inhibited cisplatin-induced apoptosis. Further investigation demonstrated that BST2-mediated cisplatin resistance depended on the activation of the NF-κB signaling pathway and consequent upregulation of anti-apoptotic genes, such as Bcl-XL and livin. Moreover, an analysis of clinical data revealed that a high BST2 level might serve as an independent indicator of poor prognosis in patients with locally advanced NPC treated with platinum-based chemoradiotherapy. These findings suggest that BST2 likely mediates platinum resistance in NPC, offering guidance for personalized and precise treatment strategies for patients with NPC.

Conventional radiological strategy of common gastrointestinal neoplasms.

This article summarizes the clinical characteristics and imaging features of common gastrointestinal (GI) neoplasms in terms of conventional radiological imaging methods. Barium studies are readily available for displaying primary malignancies and are minimally or not at all invasive. A neoplasm may be manifested as various imaging findings, including mucosal disruption, soft mass, ulcer, submucosal invasion and lumen stenosis on barium studies. Benign tumors typically appear as smoothly marginated intramural masses. Malignant neoplasms most often appear as irregular infiltrative lesions on barium examination. Tumor extension to adjacent GI segments may be indistinct on barium images. Cross-sectional images such as computed tomography and magnetic resonance imaging may provide more accurate details of the adjacent organ invasion, omental or peritoneal spread.

Nasopharyngeal tuberculosis: CT and MRI findings in thirty-six patients.

PURPOSE: Tuberculosis is uncommon in the nasopharynx. The purpose of this study was to investigate the CT and MRI features of 36 cases of tuberculosis in this area. MATERIALS AND METHODS: CT (n=15) and MRI (n=21) scans from 36 patients with histologically proved tuberculosis of the nasopharynx were reviewed by two experienced radiologists, paying particular attention to the lesions' distribution, location, extent, size, internal architecture, pattern, and degree of enhancement, and cervical lymphadenopathy. RESULTS: Twenty-nine patients exhibited a polypoid mass pattern and seven had diffuse mucosal thickening. The roof of the nasopharynx was involved in all cases. The mean size of the lesions was 11.4mm. Striped pattern was detected in 19 cases. Adjacent muscle invasion or bone destruction was not detected. Heterogeneous enhancement was detected in all patients, and necrosis in the nasopharyngeal lesions was detected in 16 cases. Poor, moderate, and marked enhancement was detected in one, 27, and eight cases, respectively. Thirty-four patients had involvement of the cervical lymph nodes. Twenty-two and 28 cases were associated with bilateral lymphadenopathy or necrosis, respectively. The retropharyngeal lymph node was the most commonly involved site (94.1%). CONCLUSION: The presence of necrosis and striped pattern in nasopharyngeal lesions, site predilection, no invasion of regional structures, and central necrosis with peripheral rim enhancement of cervical lymphadenopathy may suggest the diagnosis of nasopharyngeal tuberculosis.

Nasopharyngeal cancer: impact of skull base invasion on patients prognosis and its potential implications on TNM staging.

PURPOSE: To evaluate patterns of skull base invasion and its possible impact on tumor (T)-staging in nasopharyngeal carcinoma (NPC) using magnetic resonance imaging (MRI). MATERIALS AND METHODS: 838 consecutive newly diagnosed by biopsy proven and untreated patients with NPC underwent MRI. The skull-base invasion of NPC was classified according to their incidence from proximal sites to more distant sites surrounding the nasopharynx as: high (≥35%), medium (≥5-35%), and low (<5%) groups. A retrospective analysis of data consisting of a 5-year follow-up was carried out. The skull base invasion was related to their tumor (T) staging and prognosis at the 5-year follow-up after treatment with definitive radiation therapy. In addition, a survival health-related quality of life (QOL), overall survival (OS), local relapse-free survival (LRFS) and distant metastasis-free survival (DMFS) were also assessed among the three groups. RESULTS: The total incidence of skull-base invasion was 65.51% (549/838). The differences in T-stage distribution, and the total survival health-related QOL, among the three groups were statistically significant (χ(2)=160.45, p<0.005; χ(2)=38.43, p<0.005, respectively). The differences between any two of the three groups were also significant, except when the medium grade was compared to the low grade. Significant differences were observed with regard to 5-year OS (83.2%, 74.7%, 59.2%, p=0.000) and DMFS (95.0%, 88.0%, 88.0%, p=0.016); no significant difference was observed in LRFS (95.3%, 95.6%, 91.23%, p=0.450). CONCLUSIONS: The results indicate that medium and low group displayed similar findings of skull base invasion, and survival status. We, therefore, propose that patients in these two groups be grouped under T4 in the TNM classification that might have a bearing in implementing optimum treatment.

[Three-dimensional white matter tractography based on diffusion-tensor magnetic resonance imaging].

OBJECTIVE: To assess the value of white matter fiber tractography based on magnetic resonance diffusion-tensor imaging (MR-DTI), a new noninvasive technique that helps estimate the structural connectivity of the brain, in understanding the anatomy of the white matter fiber tract. METHODS: Six consecutive volunteers received MR-DTI examination using a GE 1.5T Sign CV/I whole-body MR system and version 2.0 Functool software for image processing. The protocol included T1WI for localization and single-shot echo-planner diffusion tensor imaging of the entire brain in axial, sagittal, and /or coronal sections. RESULTS: White matter fiber tracts imaged by MR-DTI were consistent with known white matter fiber anatomy. The major fiber tracts were well observed in all the cases. The tracts visualized included the corpus callosum, anterior commissure, uncinate fasciculus superior and inferior longitudinal fascicules, inferior occipito-frontal fasciculus, internal capsule and corona radiate. CONCLUSION: A set of detailed white matter fiber anatomy maps of the normal brain is obtained by means of single-shot echo-planner diffusion tensor imaging at high resolution. This technique allows rapid visualization of the white matter tracts in vivo, and provides a new reliable means for studying fiber connectivity in the brain.

[Diffusion tensor imaging of the white matter tracts in preoperative patients with cerebral neoplasm].

OBJECTIVE: To evaluate the quantitative relationship between white matter tract (WMT) variation resulting from cerebral tumors and shifting of the fractional anisotropy (FA) index in magnetic resonance (MR) diffusion tensor imaging (DTI). METHODS: Four female and 8 male patients aged from 21 to 62 years with brain malignancies (2 malignant lymphomas, 2 low-grade astrocytomas, and 8 high-grade cerebral gliomas) underwent conventional contrast-enhanced MR and DTI examinations before operation. Routine T(2)-weighted image, fractional anisotropic (FA) map, color-coded directional map, three-dimensional white matter tractography (WMT), and the FA index of bilateral internal capsule were obtained in every patient. RESULTS: Fiber tractography derived from DTI was consistent with known white matter fiber anatomy. The DTI patterns in WMT altered by the tumor were categorized on the basis of FA1/FA2 ratio as follows: pattern 1, FA1/FA2> or =75% with normal or only slightly decreased FA; pattern 2, 50%< or =FA1/FA2<75% with WMT displacement; pattern 3, 25%< or =FA1/FA2/50% with WMT involvement; pattern 4, FA1/FA2<25% with WMT destruction. CONCLUSIONS: DTI allows for visualization of WMT and benefits surgical planning for patients with intrinsic brain tumor. There is a positive relationship between the bilateral FA ratio (FA1/FA2) variation and WMT alterations resulting from the tumor.