Radiological model based on the standard magnetic resonance sequences for detecting methylguanine methyltransferase methylation in glioma using texture analysis.

This study aims to build a radiological model based on standard MR sequences for detecting methylguanine methyltransferase (MGMT) methylation in gliomas using texture analysis. A retrospective cross-sectional study was undertaken in a cohort of 53 glioma patients who underwent standard preoperative magnetic resonance (MR) imaging. Conventional visual radiographic features and clinical factors were compared between MGMT promoter methylated and unmethylated groups. Texture analysis extracted the top five most powerful texture features of MR images in each sequence quantitatively for detecting the MGMT promoter methylation status. The radiomic signature (Radscore) was generated by a linear combination of the five features and estimates in each sequence. The combined model based on each Radscore was established using multivariate logistic regression analysis. A receiver operating characteristic (ROC) curve, nomogram, calibration, and decision curve analysis (DCA) were used to evaluate the performance of the model. No significant differences were observed in any of the visual radiographic features or clinical factors between different MGMT methylated statuses. The top five most powerful features were selected from a total of 396 texture features of T1, contrast-enhanced T1, T2, and T2 FLAIR. Each sequence's Radscore can distinguish MGMT methylated status. A combined model based on Radscores showed differentiation between methylated MGMT and unmethylated MGMT both in the glioblastoma (GBM) dataset as well as the dataset for all other gliomas. The area under the ROC curve values for the combined model was 0.818, with 90.5% sensitivity and 72.7% specificity, in the GBM dataset, and 0.833, with 70.2% sensitivity and 90.6% specificity, in the overall gliomas dataset. Nomogram, calibration, and DCA also validated the performance of the combined model. The combined model based on texture features could be considered as a noninvasive imaging marker for detecting MGMT methylation status in glioma.

Comparison of Radiomics Analyses Based on Different Magnetic Resonance Imaging Sequences in Grading and Molecular Genomic Typing of Glioma.

OBJECTIVE: To investigate the value of radiomics analyses based on different magnetic resonance (MR) sequences in the noninvasive evaluation of glioma characteristics for the differentiation of low-grade glioma versus high-grade glioma, isocitrate dehydrogenase (IDH)1 mutation versus IDH1 wild-type, and mutation status and 6-methylguanine-DNA methyltransferase (MGMT) promoter methylation (+) versus MGMT promoter methylation (-) glioma. METHODS: Fifty-nine patients with untreated glioma who underwent a standard 3T-MR tumor protocol were included in the study. A total of 396 radiomics features were extracted from the MR images, with the manually delineated tumor as the volume of interest. Clinical imaging diagnostic features (tumor location, necrosis/cyst change, crossing midline, and the degree of enhancement or peritumoral edema) were analyzed by univariate logistic regression to select independent clinical factors. Radiomics and combined clinical-radiomics models were established for grading and molecular genomic typing of glioma by multiple logistic regression and cross-validation. The performance of the models based on different sequences was evaluated by using receiver operating characteristic curves, nomograms, and decision curves. RESULTS: The radiomics model based on T1-CE performed better than models based on other sequences in predicting the tumor grade and the IDH1 status of the glioma. The radiomics model based on T2 performed better than models based on other sequences in predicting the MGMT methylation status of glioma. Only the T1 combined clinical-radiomics model showed improved prediction performance in predicting tumor grade and the IDH1 status. CONCLUSIONS: The results demonstrate that state-of-the-art radiomics analysis methods based on multiparametric MR image data and radiomics features can significantly contribute to pretreatment glioma grading and molecular subtype classification.

Increased risk of post-stroke epilepsy in Chinese patients with a TRPM6 polymorphism.

OBJECTIVES: We attempted to determine whether a functional polymorphism of TRPM6 (rs2274924) is associated with susceptibility to epilepsy following ischemic stroke, and to further explore the effect of this polymorphism on serum levels of Mg2+ in post-stroke patients. METHODS: We carried out a case-control study on 378 post-stroke epilepsy patients and 420 controls (stroke patients without secondary epilepsy). We used DNA sequencing to determine the genotypes of the TRPM6 rs2274924 polymorphism, and used the ion selective electrode method to measure serum levels of Mg2+. RESULTS: The distribution of the CC genotype and the frequency of the C allele were significantly higher in the post-stroke epilepsy patients than in the controls (P < 0.01). With regard to the post-stroke epilepsy patients, the serum levels of Mg2+ decreased significantly in the TRPM6 rs2274924 C allele carriers compared to the rs2274924 T allele carriers. CONCLUSION: The TRPM6 rs2274924 polymorphism may be associated with susceptibility to epilepsy following stroke, and the C allele may be associated with increased risk of post-stroke epilepsy. The TRPM6 rs2274924 polymorphism may also influence serum levels of Mg2+ in post-stroke epilepsy patients.

δ-Opioid Receptor Activation Attenuates the Oligomer Formation Induced by Hypoxia and/or α-Synuclein Overexpression/Mutation Through Dual Signaling Pathways.

We have recently demonstrated that δ-opioid receptor (DOR) activation attenuates α-synuclein expression/aggregation induced by MPP(+) and/or severe hypoxia. Since α-synuclein plays a critical role in the pathogenesis of Parkinson's disease, DOR activation may trigger an antiparkinson pathway(s) against α-synuclein-induced injury. However, the underlying mechanism is unknown yet. In HEK293T and PC12 cells, we investigated the effects of DOR activation on the oligomer formation induced by α-synuclein overexpression and mutation in normoxic and hypoxic conditions and explored the potential signaling pathways for DOR protection. We found that (1) increased expression of both wild-type and A53T-mutant α-synuclein led to the formation of α-synuclein oligomers and cytotoxic injury; (2) DOR activation largely attenuated the formation of toxic α-synuclein oligomers induced by α-synuclein overexpression/mutation and/or hypoxia; (3) DOR activation attenuated α-synuclein-induced cytotoxicity through TORC1/SIK1/CREB, but not the phospho-CREB pathway, while DOR activation reduced hypoxic cell injury through the phospho-CREB mechanism; and (4) the interaction of α-synuclein and the DJ-1 was involved in the mechanisms for DOR-mediated protection against α-synuclein oligomer formation. Our findings suggest that DOR attenuates the formation of toxic α-synuclein oligomers through the phos-CREB pathway under hypoxic conditions, and through TORC1/SIK1/CREB pathways in the conditions of α-synuclein overexpression and mutation. The DJ-1 gene was involved in the DOR protection against parkinsonian injury.

The delta-opioid receptor and Parkinson's disease.

Parkinson's disease (PD) is a common degenerative neurological disease leading to a series of familial, medical, and social problems. Although it is known that the major characteristics of PD pathophysiology are the dysfunction of basal ganglia due to injury/loss of dopaminergic neurons in the substantia nigra pars compacta dopaminergic and exhaustion of corpus striatum dopamine, therapeutic modalities for PD are limited in clinical settings up to date. It is of utmost importance to better understand PD pathophysiology and explore new solutions for this serious neurodegenerative disorder. Our recent work and those of others suggest that the delta-opioid receptor (DOR) is neuroprotective and serves an antiparkinsonism role in the brain. This review summarizes recent progress in this field and explores potential mechanisms for DOR-mediated antiparkinsonism.

Kissing aneurysms of the distal anterior cerebral artery: A case report and literature review.

Intracranial 'kissing' aneurysms are rare types of multiple aneurysms referring to two adjacent aneurysms arising from identical or different arteries with separate origins and partially adherent walls. The present study reported a 54-year-old female patient, who was identified with a 'kissing' aneurysm in the A3 segment of the bilateral anterior cerebral arteries, as demonstrated by head computed tomography and emergency cerebral digital subtraction angiography analysis. In total, 12 days following the clipping of the aneurysms, the patient was discharged with a Modified Rankin Scale=0 and recovered well with no neurological deficits. Based on previous literature, it was indicated that the majority of patients with 'kissing' aneurysm have a good prognosis and the cure rate is as high as 96.8%. However, the recovery rate may not be that high as the sample size is not large enough to thoroughly demonstrate the complete prognosis of 'kissing' aneurysms.

Blood-Brain Barrier Disruption, Sodium Fluorescein, And Fluorescence-Guided Surgery Of Gliomas.

PURPOSE: Sodium fluorescein (SF) is an ideal dye for intraoperative guided-resection of high-grade gliomas (HGGs). However, it is not well understood whether the SF-guided technique is suitable for different grades of gliomas, and the correlation between fluorescence and pathology is also not yet clear. MATERIALS AND METHODS: In this study, we investigated 28 patients, including 23 patients with HGG and 5 patients with low-grade glioma (LGG). All patients were treated using the SF-guided technique on a Pentero 900 microscope (Carl Zeiss, Oberkochen, Germany). Claudin-5 immunohistochemical (IHC) staining for the tumours and peritumour tissues was analyzed. RESULTS: Intraoperative yellow fluorescence was noted in all the HGGs but not in the LGGs. Claudin-5 expression in the blood brain barrier endothelial cells was downregulated and disconnected in the HGGs (p < 0.05), but had no difference or slightly decreased in the LGGs (p > 0.05). CONCLUSIONS: The SF-guided technique is suitable for HGG surgery but not for LGG surgery. Downregulation of claudin-5 expression may contribute to the presence of yellow fluorescence in the glioma in SF-guided surgery.

MiR-206 is down-regulated and suppresses cell proliferation by targeting FOXP1 in brain gliomas.

Aberrant expression of miR-206 has been repeatedly found and demonstrated to play crucial roles in cancers. However, the role of miR-206 in brain glioma remains unclear. To address this issue, we detected miR-206 expression of 60 gliomas and 18 normal peritumor tissues, and found that miR-206 is significantly down-regulated in gliomas. Further in silico analysis of 198 glioma samples from the Chinese Glioma Genome Atlas (CGGA) indicated that miR-206 is significantly down-regulated in high grade gliomas and that miR-206 predicts favorable patients' prognosis. Notably, we found that miR-206 expression is negatively correlated with Ki-67 staining, indicating a proliferative inhibition of miR-206 in gliomas. To explore the crucial role of miR-206 in gliomas, we constructed miR-206 stably overexpressed LN229 glioma cell lines and found that the proliferation is significantly inhibited. Through flow cytometry (FCM) analyses, we found that the apoptotic rate is increased and the cell cycle is arrested in LN229 cells after overexpression of miR-206. Bioinformatic analysis, qPCR, western blot and luciferase assay indicated that the Forkhead Box Protein 1 (FOXP1) is a direct target of miR-206 in gliomas. Overexpression of FOXP1 could partially rescue the proliferative inhibition in the miR-206 stably overexpressed LN229 cells. In summary, our results suggest that miR-206 might function as a tumor suppressor of gliomas by inhibition of proliferation and could serve as a promising candidate for therapeutic applications in glioma by targeting FOXP1.

Chronic hepatitis B: correlation of abnormal features on T2-weighted imaging and dynamic contrast-enhanced imaging with hepatic histopathology.

OBJECTIVES: To investigate the correlations between abnormal features on liver magnetic resonance (MR) T2-weighted imaging (T2WI) and dynamic contrast-enhanced (DCE) imaging and the pathological findings in chronic hepatitis B. MATERIALS AND METHODS: Sixty-seven patients with chronic hepatitis B and 18 normal controls who were undergone an abdominal MR imaging were analyzed retrospectively. Patchy hyperintensities, linear and reticular hyperintensities in liver and periportal edema on T2WI and abnormal intrahepatic enhancement signals on DCE imaging were noted. The correlations between the abnormal features detected on hepatic T2WI and DCE imaging, and the levels of inflammatory activity and fibrosis were determined. RESULTS: Logistic regression analysis showed increased patchy hyperintensities (B = 1.869, P = 0.001) on T2WI and patchy enhancement (B = 1.596, P = 0.004) at the arterial phase along with increased inflammatory activity. However, linear and reticular hyperintensities (B = 2.356, P = 0.000) on T2WI, and meshwork enhancement (B = 2.191, P = 0.000) at the equilibrium phase, all correlated with fibrosis. Moreover, periportal edema mainly correlated with the inflammatory activities (B = 2.635, P = 0.001). CONCLUSIONS: In chronic hepatitis B patients, patchy hyperintensities on T2WI, periportal edema, and patchy enhancement at the arterial phase can predict moderate-to-severe inflammatory activities, whereas intrahepatic linear and reticular hyperintensities on T2WI, and meshwork enhancement at the equilibrium phase can predict moderate-to-severe fibrosis.

Abnormal spontaneous brain activity in minimal hepatic encephalopathy: resting-state fMRI study.

PURPOSE: We aimed to assess the abnormality of baseline spontaneous brain activity in minimal hepatic encephalopathy (MHE) by amplitude of low frequency fluctuation (ALFF) and fraction ALFF (fALFF). METHODS: A total of 14 MHE patients and 14 healthy controls were included in our study. Both ALFF and fALFF of functional magnetic resonance imaging were calculated for statistical analysis. RESULTS: Compared with healthy controls, patients with MHE had significantly decreased ALFF in the bilateral medial prefrontal cortex (MPFC), left superior frontal gyrus, right precentral gyrus, left opercular part of inferior frontal gyrus, left gyrus rectus, bilateral precuneus, and the posterior lobe of right cerebellum; and they had significantly decreased fALFF in the bilateral MPFC, right middle frontal gyrus, right superior temporal gyrus, and the posterior lobe of left cerebellum. CONCLUSION: ALFF and fALFF changes in many brain regions demonstrate abnormality of the spontaneous neuronal activity in MHE. Especially the impairment of right precuneus and left MPFC may play a critical role in manifestation of MHE. Changes of ALFF and fALFF in the precuneus and the MPFC can be used as a potential marker for MHE.

The Value of Proton Magnetic Resonance Spectroscopy in High-Intensity Focused Ultrasound Treatment of Experimental Liver Cancer.

High-intensity focused ultrasound (HIFU) is a rapidly developing, non-invasive technique for local treatment of solid tumors that produce coagulative tumor necrosis. This study is aimed to investigate the feasibility of proton magnetic resonance spectroscopy (MRS) on early assessing treatment of HIFU ablation in rabbit with VX2 liver tumor. HIFU ablation was performed on normal liver and VX2 tumor in rabbit, and MRS was performed on normal liver and VX2 tumor before and 2 days after 100% HIFU ablation or 80% ablation in tumor volume. Choline (Cho) and choline/lipid (Cho/Lip) ratios between complete and partial HIFU ablation of tumor were compared. Tissues were harvested and sequentially sliced to confirm the necrosis. In normal liver, the Cho value liver was not obviously changed after HIFU (P > .05), but the Cho/Lip ratio was decreased (P < .05). Cho in liver VX2 tumor was much higher than that in normal liver (P < .001). Cho and Cho/Lip ratio were significantly decreased in tumor after complete HIFU ablation and partial HIFU ablation, and the Cho value in complete HIFU tumor ablation did not show any difference from that in normal liver after HIFU (P > .05); however, the Cho value in partial ablation was still higher than that in normal liver before or in tumor after complete HIFU treatment due to the residual part of tumors, and Cho/Lip ratio is lower than that in complete HIFU treatment (P < .001). The changes in MRS parameters were consistent with histopathologic changes of the tumor tissues after treatment. MRS could differentiate the complete tumor necrosis from residual tumor tissue, when combined with magnetic resonance imaging. We conclude that MRS may be applied as an important, non-invasive biomarker for monitoring the thoroughness of HIFU ablation.

Efficacy of HGF carried by ultrasound microbubble-cationic nano-liposomes complex for treating hepatic fibrosis in a bile duct ligation rat model, and its relationship with the diffusion-weighted MRI parameters.

Hepatic fibrosis is a major consequence of liver aggression. Finding novel ways for counteracting this damaging process, and for evaluating fibrosis with a non-invasive imaging approach, represent important therapeutic and diagnostic challenges. Hepatocyte growth factor (HGF) is an anti-fibrosis cell growth factor that induces apoptosis in activated hepatic stellate cells, reduces excessive collagen deposition, and stimulates hepatocyte regeneration. Thus, using HGF in gene therapy against liver fibrosis is an attractive approach. The aims of the present study were: (i) to explore the efficacy of treating liver fibrosis using HGF expression vector carried by a novel ultrasound microbubble delivery system; (ii) to explore the diagnostic interest of diffusion-weighted MRI (DWI-MRI) in evaluating liver fibrosis. We established a rat model of hepatic fibrosis. The rats were administered HGF linked to novel ultrasound micro-bubbles. Progression of hepatic fibrosis was evaluated by histopathology, hydroxyproline content, and DWI-MRI to determine the apparent diffusion coefficient (ADC). Our targeted gene therapy produced a significant anti-fibrosis effect, as shown by liver histology and significant reduction of hydroxyproline content. Moreover, using DWI-MRI, the b value (diffusion gradient factor) was equal to 300s/mm(2), and the ADC values significantly decreased as the severity of hepatic fibrosis increased. Using this methodology, F0-F2 could be distinguished from F3 and F4 (P<0.01). This is the first in vivo report of using an ultrasound microbubble-cationic nano-liposome complex for gene delivery. The data indicate that, this approach is efficient to counteract the fibrosis process. DWI-MRI appears a promising imaging technique for evaluating liver fibrosis.

Chronic hepatitis B: Enlarged perihepatic lymph nodes correlated with hepatic histopathology.

AIM: To assess the value of enlarged perihepatic lymph nodes in determining hepatic histopathology for chronic hepatitis B (CHB) by magnetic resonance imaging (MRI). METHODS: Sixty-seven patients who were clinically and histologically diagnosed with CHB and 18 healthy subjects without history of liver disease underwent abdominal MRI. Histological diagnosis and hepatic inflammation (grade 0-4) and fibrosis (stage 0-4) were assessed by a simplified system for scoring in chronic viral hepatitis. The major imaging protocol included an axial breath-hold fat suppressed fast spoiled gradient echo T2-weighted imaging (T2WI), axial breath-trigger fat suppressed fast recovery fast spin echo T2WI, and axial and coronal fast imaging employing steady-state acquisition. Perihepatic lymph nodes larger than 5 mm in shortest diameter were noted. RESULTS: The numbers and size indexes of lymph nodes greater than 5 mm in shortest diameter in hepatic hilum suggested inflammatory activity for subjects with grade 2 or higher, with a high accuracy of diagnosis (the area under the curves > 0.9, P < 0.001). The numbers of lymph nodes were 2 or more with a sensitivity of 87.27%, a specificity of 90.00%, an accuracy of 88.24%, a positive predictive value of 94.12%, and a negative predictive value of 79.41% in patients with grade 2 or higher, and the size indexes were no less than 180 mm(2) with a sensitivity of 83.64%, a specificity of 100%, an accuracy of 89.41%, a positive predictive value of 100%, and a negative predictive value of 76.92%. The numbers and size indexes of lymph nodes were not correlated with hepatic fibrosis. The signal intensity indexes of lymph nodes were no significant correlation with histological grading or staging of liver. CONCLUSION: The numbers and size indexes of enlarged perihepatic lymph nodes for patients with CHB suggest inflammatory activity for subjects with grade 2 or higher.

Oedema of gallbladder wall: correlation with chronic hepatitis B on MR imaging.

PURPOSE: The aim of this study was to characterise gallbladder wall oedema and correlate it with chronic hepatitis B (CHB) on magnetic resonance (MR) imaging. MATERIALS AND METHODS: Sixty-seven patients who were clinically and histologically diagnosed with CHB and 18 healthy individuals without any history of liver disease underwent abdominal MR imaging. Hepatic inflammation (grade 0-4) and fibrosis (stage 0-4) for patients were assessed histologically. Gallbladder wall oedema was noted. RESULTS: Twelve patients showed gallbladder wall oedema on MR imaging, including six with grade 3 and six with grade 4 disease. There was a statistically significant difference for the presence of gallbladder wall oedema among groups with grade 0-4 (p=0.000), but not between groups with grades 3 and 4 (p=0.729). Gallbladder wall oedema was related to moderate-severe inflammatory activity (p<0.05), alanine transaminase (ALT) (p=0.012) and aspartate aminotransferase (AST) (p=0.027) levels but not to fibrosis or other laboratory data, including serum quantitative DNA for hepatitis B virus (HBV), with the p=0.105-0.846. Sensitivity and specificity for the diagnosis of hepatic moderate-severe inflammation using gallbladder wall oedema were 33.33% and 100%, respectively. CONCLUSIONS: Gallbladder wall oedema for patients with CHB can be specifically demonstrated on MR imaging and is correlated with hepatic moderate-severe inflammatory activity, elevated ALT and AST levels but not with fibrosis or other laboratory data, including viremia.

[Preparation and in vitro study of a high molecular weight contrast agent targeting hepatoma cells].

OBJECTIVE: To prepare a specific high molecular weight polymer contrast agent capable of specifically targeting hepatocarcinoma cells (HCC) and to investigate its affinity in vitro using HepG2 cells. METHODS: The high molecular weight polymer polylactic-co-glycolic acid (PLAG)-COOH was prepared by the double emulsion technique. PLAG-COOH microbubbles were combined with glypican-3 (GPC3) antibody to generate HCC targeting high molecular polymer ultrasound contrast agents by the carbodiimide method. The affinity for HCC cells was confirmed by measuring attachment to cultured HepG2 cells by flow cytometry and comparing the results with the properties observed for non-targeted high molecular weight polymer ultrasound contrast agents. RESULTS: The average diameter of the targeted high molecular weight polymer ultrasound contrast agents was (800+/-10) nm. In vitro targeting of HepG2 cells showed that many of the targeted high molecular weight polymer ultrasound contrast agents attached tightly to the cell surface and that the GPC3-PLGA has a particularly strong targeting ability. CONCLUSION: A HCC-specific high molecular contrast agent, GPC3-PLGA, was synthesized and evidenced a strong targeting ability towards HepG2 cells in vitro. This new agent may be exploited to improve diagnosis of liver cancer at the molecular level.

[1H magnetic resonance spectroscopy in the evaluation of high intensity focused ultrasound ablation for primary liver cancer].

To investigate the clinical value of 1H magnetic resonance spectroscopy (1H MRS) in the evaluation of high intensity focused ultrasound (HIFU) ablation for primary liver cancer. Routine magnetic resonance sequences, contrast-enhanced magnetic resonance imaging and respiratory-triggered single voxel point resolved spectroscopy sequence (PRESS) were performed on 24 patients with primary liver cancer before and after HIFU ablation. A respiratory-triggered axial T2 weighted imaging (T2WI) was used as localizer for PRESS. Spectroscopy data was transmitted to a personal computer and was post-processed with a custom software (Saker, provided by Ning Jing, an engineer in GE Healthcare). It would be considered "technical success" if the baselines of spectra were stable and main metabolites were without overlapping and could be identified. Integral areas of choline (Cho) peak at 3.2 parts per million (ppm) and lipid (Lip) peak at 1.3 ppm were measured, and the choline to lipid (Cho/Lip) ratios were calculated. The differences of areas of Cho, Lip peak and Cho/Lip ratios before and after HIFU ablation were compared by using paired samples t test, and a P value of less than 0.05 was considered statistically significant. The technical success rate of 1H-MRS was 87.50% (42/48). Integral areas of Cho peak and Lip peak of 20 patients with satisfied spectra were measured, and the Cho/Lip ratios were calculated. The Integral area of Cho peak decreased from 34 597+/-6 802 before HIFU ablation to 6 372+/-2 466 after HIFU ablation (t = 18.02, P less than 0.01). The Integral area of Lip peak increased from 147 948+/-16 317 before HIFU ablation to 149 069+/-16 345 after HIFU ablation (t = -15.11, P less than 0.01). The Cho/Lip ratio decreased from 0.23+/-0.03 before HIFU ablation to 0.04+/-0.02 after HIFU ablation (t = 25.32, P less than 0.01). 1H-MRS could provide information of metabolites changes of primary liver cancer after HIFU ablation and could be used as a complementary sequence to other magnetic resonance sequences to evaluate all around primary liver cancer after HIFU ablation.

[CT image of liver secondary lymphoma].

OBJECTIVE: To analyze the CT image characteristics of liver secondary lymphoma. METHODS: The medical records of 13 patients were reviewed. There were 12 non-Hodgkin lymphoma cases and 1 Hodgkin lymphoma case. Abdomen CT scan was performed in all cases, plain scan and enhanced CT scan were performed in 11 cases, plain CT scan was performed in 2 cases. RESULTS: Of the 13 cases, 11 were nodular type, 1 was diffuse type, and 1 was mixed type. Plain CT scan showed low density, enhanced CT showed circular enhancement in 1 case, mild to midrange delayed enhancement in 1 case, midrange enhancement in 1 case, mild enhancement in 2 cases, blood vessel floating sign in 3 cases, no enhancement in 6 cases. CONCLUSIONS: The characteristics of liver secondary lymphoma CT image of liver secondary lymphoma includes blood vessel floating sign and enhancement.

[Establishment of liver fibrosis in rabbit model and quantitative study on hepatic perfusion with dynamic whole-liver 3D MR imaging].

OBJECTIVE: To investigate the ideal approach in creating rabbit model of hepatic fibrosis and to evaluate the feasibility and value of dynamic whole-liver 3D magnetic resonance (MR) perfusion-weighted imaging (PWI) in the quantitative study on the staging of hepatic fibrosis. METHODS: Rabbit model of hepatic fibrosis was created by intraperitoneal injection of 5% and 100% carbon tetrachloride (0.1 ml/kg, once a week) respectively. MR perfusion weighted imaging was performed at the 6th, 8th, 10th and 12th week since injection. The time of peak (TOP), the time to peak (TTP), the maximum slope of increase(MSI) and the maximal relative signal increase (MRSI) of portal vein and hepatic parenchyma were analyzed quantitatively, and were compared with pathological results. Comparison of different concentrations of CCl4 was analyzed using chi-square test. Inter-group comparison of perfusion parameters was analyzed using one-way ANOVA P less than 0.05 was regarded as statistically significant. RESULTS: 40% of the rabbits treated with 5% carbon tetrachloride developed hepatic fibrosis, while 75% of the rabbits treated with 100% carbon tetrachloride developed hepatic fibrosis; the mortality rate is significantly different between these two groups (X2=5.013, P less than 0.05). PWI examination was successfully achieved in 31 rabbits, liver perfusion baseline was stable, and good TIC curve was obtained. With the progress of hepatic fibrosis, TOP and TTP of portal vein and hepatic parenchyma were increased, and MSI and MRSI were decreased. There were significant differences among stage of S0-S2, S3 and S4. CONCLUSIONS: The method (100% carbon tetrachloride intraperitoneal injection, 0.1 ml/kg, once a week) has high success rate of creating rabbit model of hepatic fibrosis. The stage of hepatic fibrosis could be evaluated quantitatively with dynamic whole-liver 3D MR perfusion-weighted imaging.

DCE-MRI in experimental chronic pancreatitis.

To assess pancreatic perfusion in experimental chronic pancreatitis (CP) by dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). DCE MRI on a 1.5 T MR scanner was performed on 21 piglets with the ligation of pancreatic duct. They were divided into four groups based on pathology, including seven normal pigs and seven, three and four piglets with grade I, II and III CP, respectively. The signal intensity measured in the pancreatic body on DCE MRI was plotted against time to create a signal intensity-time (SI-T) curve for each piglet. The steepest slope (SS), time-to-peak (TTP) and peak enhancement ratio (PER) of the SI-T curve were noted. In the four groups, on the SI-T curve derived from DCE MRI, the SS was, respectively, 10.88 +/- 1.20, 10.59 +/- 1.02, 6.67 +/- 1.31 and 5.48 +/- 1.97%/s (F = 20.509, p = 0.000) from normal piglets to piglets with grade III CP. The TTP was 13.82 +/- 3.09, 12.31 +/- 5.52, 20.55 +/- 3.79 and 37.26 +/- 14.56 s (F = 10.681, p = 0.000) and the PER was 62.95 +/- 20.20, 60.44 +/- 20.00, 46.33 +/- 22.70 and 67.65 +/- 32.66% (F = 0.529, p = 0.668), respectively. The SS (r = -0.719, p = 0.000) and TTP (r = 0.538, p = 0.012) of the SI-T curve was correlated to the severity of CP, respectively. DCE MRI has a potential to diagnose moderate to advanced CP. The SS and TTP of the SI-T curve were correlated to the severity of CP.

[Expression of peroxisome proliferator-activated receptor-gamma in human pituitary adenomas and its correlation to tumor invasiveness].

BACKGROUND & OBJECTIVE: Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a nuclear transcription factor. Its ligant can inhibit proliferation and enhance differentiation of tumor cells, which plays crucial roles in metastasis and invasion of tumors. This study was to investigate the expression of PPARgamma in human pituitary adenomas and its clinical significance. METHODS: Immunohistochemistry (IHC) was used to investigate the expression of PPARgamma protein in 78 human pituitary adenomas, including 41 invasive and 37 non-invasive cases. The expression levels of PPARgamma mRNA in 33 human pituitary adenomas, including 16 invasive and 17 non-invasive cases, and three normal pituitary tissues obtained from autopsy were confirm by reverse transcription polymerase chain reaction (RT-PCR). The expression of PPARgamma in invasive and non-invasive pituitary adenomas was analyzed by Chi2 test and t test of the fourfold table. RESULTS: The positive rate of PPARgamma protein was significantly higher in invasive pituitary adenomas than in non-invasive ones (68.09% vs. 38.71%,P<0.05). The PPARgamma mRNA level was significantly higher in pituitary adenomas than in normal pituitary tissues (2.99+/-0.18 vs. 1.55+/-0.25, P<0.05), and higher in invasive pituitary adenomas than in non-invasive cases (3.95+/-0.43 vs. 2.40+/-0.24, P<0.01). CONCLUSIONS: PPARgamma is highly expressed in human pituitary adenomas, especially in the invasive ones. PPARgamma may be used as a new target for the treatment of pituitary adenomas.