MR imaging manifestations of extraventricular neurocytoma / 实用放射学杂志

Objective To analyze retrospectively the MR manifestations and differential diagnosis of extraventricular neurocytoma (EVN).Methods 7 patients with EVN confirmed by pathologic examination were performed non-enhanced and contrast-enhanced MR scan,and one of them was also performed DWI.Results 4 tumors were located in cerebra,2 tumors located in cerebellum,involving both cortex and white matter,and 1 tumor was located in the seller region.5 tumors were solid-cystic lesions and 2 tumors were solid lesions.5 lesions were well demarcated and 2 lesions were ill defined.Edema around the lesion was found in 2 cases.The solid part of tumors showed iso-or hyper intensity on T1WI,hypo-or hyper intensity on T2WI.Necrosis and hemorrhage occurred in some cases.The degree of enhancement in solid part ranged from mild enhancement to intense enhancement heterogeneously.The cystic part showed ring like enhancement with a thin wall.Conclusion The manifestations of EVN on MRI have some characteristics.If a solid-cystic lesion was well defined,involving both cortex and white matter,EVN should be considered.

The effect of a multi-material artifact reduction algorithm in a wide-detector CT system to reduce the beam hardening artifacts in CT imaging / 中华放射学杂志

Objective To investigate the effect of the multi-material artifact reduction (MMAR) algorithm of wide-detector CT system in reducing the beam hardening artifacts in brain CT imaging. Methods Nine tubes with various iodine concentrations (0.1-16.0 mgI/ml) were placed in a uniform phantom filled with soft-tissue equivalent material. The phantom was scanned using different combinations of the tube voltage and current as follows:80 kV/530 mA, 100 kV/295 mA, 120 kV/190 mA and 140 kV/135 mA. The scanning was performed using the GE Discovery 750 and GE Revolution CT scanners, respectively. The CT values and standard deviations of the uniform areas between tubes were measured. The artifact index (AI) was calculated by using the standard deviation value outside the tubes as background noise. The artifact index values under different kV/mA combinations with different scanners were compared. CT brain images of 36 patients (n=18 on Discovery CT and n=18 on Revolution CT) were randomly selected. CT values of normal brain tissue and dark bands areas in the posterior fossa were measured for each case. The AI was calculated for these cases as for the phantom study. Paired t test was performed for phantom data analysis, and independent t test was performed for the clinical cases data analysis. Results The average AI values with Revolution CT(4.96±1.39, 4.80±1.57, 4.56±1.45, 4.76±1.57) were smaller than those of Discovery 750 (11.90 ± 6.61, 11.17 ± 5.61, 8.85 ± 4.59, 8.77 ± 3.85) under different tube voltage settings(t=3.714, 4.186, 3.745, 4.634,P<0.001). The higher the iodine concentration difference between tube pairs was, the higher the artifact index;As for clinical data, the difference in AI values between Revolution CT(2.31 ± 0.95) and Discovery 750(3.91 ± 1.32) was found statistically significant(t=4.066,P<0.001). Conclusion The multi-material artifact reduction algorithm implemented on the wide-detector Revolution CT scanner can significantly reduce beam hardening artifacts.

The effect of a multi-material artifact reduction algorithm in a wide-detector CT system to reduce the beam hardening artifacts in CT imaging / 中华放射学杂志

Objective To investigate the effect of the multi-material artifact reduction (MMAR) algorithm of wide-detector CT system in reducing the beam hardening artifacts in brain CT imaging. Methods Nine tubes with various iodine concentrations (0.1-16.0 mgI/ml) were placed in a uniform phantom filled with soft-tissue equivalent material. The phantom was scanned using different combinations of the tube voltage and current as follows:80 kV/530 mA, 100 kV/295 mA, 120 kV/190 mA and 140 kV/135 mA. The scanning was performed using the GE Discovery 750 and GE Revolution CT scanners, respectively. The CT values and standard deviations of the uniform areas between tubes were measured. The artifact index (AI) was calculated by using the standard deviation value outside the tubes as background noise. The artifact index values under different kV/mA combinations with different scanners were compared. CT brain images of 36 patients (n=18 on Discovery CT and n=18 on Revolution CT) were randomly selected. CT values of normal brain tissue and dark bands areas in the posterior fossa were measured for each case. The AI was calculated for these cases as for the phantom study. Paired t test was performed for phantom data analysis, and independent t test was performed for the clinical cases data analysis. Results The average AI values with Revolution CT(4.96±1.39, 4.80±1.57, 4.56±1.45, 4.76±1.57) were smaller than those of Discovery 750 (11.90 ± 6.61, 11.17 ± 5.61, 8.85 ± 4.59, 8.77 ± 3.85) under different tube voltage settings(t=3.714, 4.186, 3.745, 4.634,P<0.001). The higher the iodine concentration difference between tube pairs was, the higher the artifact index;As for clinical data, the difference in AI values between Revolution CT(2.31 ± 0.95) and Discovery 750(3.91 ± 1.32) was found statistically significant(t=4.066,P<0.001). Conclusion The multi-material artifact reduction algorithm implemented on the wide-detector Revolution CT scanner can significantly reduce beam hardening artifacts.

MRI features of Rosai-Dorfman disease in CNS / 实用放射学杂志

Objective To summarize the clinical and imaging characteristics of primary Rosai-Dorfman disease (RDD)in central nervous system in order to understand well its features and improve the diagnosis.Methods The clinical and imaging features in 3 patients with RDD in CNS proved by pathology were retrospectively analyzed in combination with the related literatures.Results The lesions in 2 patients occurred in brain and other lesion in 1 occurred outside the brain.Iso-or slight hyperintensity on T1 WI and marked enhancement of the lesion were found.Single lesion was found in 2 patients near the dura mater and located near the superior sagittal sinus or cervical spinal cord.Multiple lesions in 1 patient were located in the lateral ventricle.Conclusion It’s suggested that single or multiple lesions in dural or spinal meninges located in the midline or near the intracephalic venous system would be considered as RDD in CNS.

Imaging and pathological features of atypical teratoid/rhabdoid tumors in the central nervous system / 实用放射学杂志

Objective To investigate the imaging and pathological features of atypical teratoid/rhab doid tumor (AT/RT)occur-ring in the central nervous system (CNS).Methods The CT and MRI findings of 1 6 patients with CNS AT/RT were retrospectively analyzed,and their pathological and immunohistochemical results were studied.Results There were 12 males and 4 females. Tumors located is at supratentorial in 10 and infratentorial in 6.Cystic changes in tumors were noted in 12 cases.The solid portion of tumors was isointense on T2-weighted images relative to normal brain grey matter in 9 patients.Extensive peritumoral edema was observed in 1 1 lesions.The tumors showed bandlike rim of significant enhancement in 10 cases.The incidence of hemorrhage and calcification in tumors were 43.8% and 41.7% respectively.Histopathologically,AT/RT was characterized by the presence of rhab-doid cells associated with variable components of epithelial,primitive neuroectodermal and mesenchymal differentiation.Conclusion Atypical teratoid/rhabdoid tumor is several imaging findings which are relatively specific on CT and MR images.CT and MRI may provide valuable information for pre-operation diagnosis and prognostic evaluation in patients with CNS AT/RT.

Prediction of subacute infarct lesion volumes by processing apparent diffusion coefficient maps based on apparent diffusion coefficient cut-off values in patients with acute stroke / 中华放射学杂志

Objective To explore the feasibility of prediction of subacute infarct lesion volumes by processing ADC maps based on ADC cut-off values in patients with acute stroke.Methods MRI was performed in 20 patients with clinically diagnosed acute infarct less than 6 h after stroke onset.The MRI included a DWI and conventional MRI.The follow-up MR examinations of all the patients were carried out within 4-7 days after admission.The brain tissue, which showed abnormal high intensity both in DWI at the baseline and FLAIR at the reexamination , was regarded as the area of the initial ischemia core.Graphic-penumbra was regarded as the difference between initial DWI and follow-up FLAIR.The ADC values of the ischemia core, graphic-penumbra and the contralateral normal brain tissue , the relative ADC (rADC) were measured.The rADC value of the graphic-penumbra was defined as the ADC cut-off values.GE medical system based on ADC cut-off values was also tested in these patients to obtain ADC maps.The lesion volumes, the abnormal area seen on the DWI , ADC maps and follow-up FLAIR, were also measured.rADC values in different areas were analyzed by paired Student t test.Relationship between baseline DWI , ADC map and follow-up FLAIR was analyzed using Spearman rank-order correlation test , and Kruskal-Wallis H test was used to compare the volumes among three groups.Results Absolute ADC and rADC values gradually increased from the core to the periphery of the ischemic lesion.The absolute ADC values statistically differed from those on the contralateral side for both ischemia core and graphic-penumbra.The rADC values were significantly decreased in the ischemia core ( 0.620 ±0.116 ) compared with the graphic-penumbra values (0.809 ±0.097;t =8.083,P 0.05).Conclusions Data shows the high feasibility of prediction of subacute infarct lesion volumes by processing ADC maps based on ADC cut-off values in patients with acute stroke , without intravenous contrast material, and it provides a new method for outcome prediction.

Comparative study of magnetic resonance elastography and T2WI in assessing stiffness of tissue / 中华放射学杂志

Objective To preliminarily compare accuracy of magnetic resonance elastography (MRE) and T2WI in assessing stiffness of tissue.Methods Agar gel phantoms of 23 different concentrations ranging from 0.8％-3.0％ were produced.All the phantoms were examined with MRE and T2 map scanning respectively.After the raw images were processed by using local wavelength estimation (LEF),shear modulus of scan slice was measured,and T2 value of the same slice was measured with GE ADW4.3 workstation.Pearson correlation analysis was used to test the correlation between shear modulus and agar concentration,as well as T2 value and concentration.Rank sum test was used to compare the correlation coefficients of them.Results All the shear modulus and T2 values of the phantoms were successfully obtained,which were (49.1 ± 23.5) kPa and (57.8 ± 21.8) ms respectively.Shear modulus was positively correlated with concentration of agar gel(r1 =0.985,r1 2 =0.970,P ＜ 0.01),while T2 value was negatively correlated with concentration of agar gel (r2 =-0.901,r22 =0.812,P ＜ 0.01).The differences of these two correlation coefficients were statistically significant (Z =5.459,P ＜ 0.01).Conclusion MRE is more accurate to reflect stiffness of tissues relative to T2WI,and shows great clinical prospect.

English training mode for young doctors in radiological department of general hospital / 中华医院管理杂志

English training is important for young doctors＇ career development in general hospital.The stagewise English training mode of Beijing Tiantan Hospital of Capital Medical University was introduced.By summarizing the experience of five years trial,viewpoints were brought forward that hospital English training in radiological department of general hospital should adopt a stagewise mode,create an English communication atmosphere,show the special feature of department and combine with clinical daily work.

Volume changes of whole brain gray matter in pediatric patients with Tourette syndrome: evidence from voxel-based morphometry / 中华放射学杂志

ObjectivesTo identify the related abnormalities of gray matter in pediatric patients with Tourette syndrome (TS) by using the optimized voxel-based morphometry (VBM).Methods Three dimensional T1WI was acquired in 31 TS children (28 boys,3 girts,mean age 8 years,range 4-15 years) and 50 age- and sex-matched controls on a 1.5 Tesla Philips scanner. Images were pre-processed and analyzed using a version of VBM 2 in SPM 2.The whole brain gray matter volume was compared between the study and control group by using t-test.Multivariate linear regression analysis was used for analyzing the correlation between the change of grey matter volume within each brain region (mm3 ) and YGTSS score and course of disease of TS patients.Statistical analyses were performed by using SPSS 13.0.ResultsUsing VBM,significant increases in gray matter volumes in left superior parietal lobule, right cerebellar hemisphere and left parahippocampal gyrus were detected in TS patients,and the volume changes were 4059,2126 and 84 mm3 ( t =3.93,3.71,3.58,P ＜ 0.05 ) respectively.Compared to the control group,decreased grey matter volumes were found in medulla and left pons,and the volume changes were 213 and 117 mm3( t =3.53,3.48,P ＜ 0.05 )respectively.Tic severity was not correlated with any volume changes of gray matter in brain (P ＞ 0.05,a small volume correction,KE ≥ 10 voxel).Tic course was negatively correlated with the gray matter volume of left parahippocampal gyrus ( Beta =- 0.391,P =0.039 ).ConclusionsUsing VBM technique,the gray matter abnormalities can be revealed in TS patients without obvious lesions on conventional MR imaging.The increasing volume of temporal and parietal lobes and cerebellar may be an adaptive anatomical change in response to experiential demand. The gray matter volume of the parahippocampal gyrus may be used as one potential objective index for evaluating the prognosis of TS.

The comparative study of the brain MR elastography between Chinese vegetarians and omnivores / 中华放射学杂志

time (r = 0. 070, -0.003, -0. 195,0. 177,P 0.05). Conclusions Compared with omnivore's, the shear stiffness of brain parenehyma was lower in vegetarians. The shear stiffness of brain parenchyma may be affected by the diet.

MR elastography study of the brain in healthy volunteers / 中华放射学杂志

Objective To evaluate the shear stiffness of brain by MR elastography (MRE) in healthy Chinese volunteers and to assess the association between the cerebral shear stiffness and age. Methods Brain MRE studies were performed on 105 healthy volunteers. The shear stiffness of brain parencham was measured by local frequency estimation (LFE) algorithm. The differences of the shear stiffness between white matter(WM) and grey matter(GM) were analyzed by independent sample t test; the differences of brain parenchyma shear stiffness between male and female were estimated by independent sample t test. Spearman test was used to analyze the correlation between age and the shear stiffness of parenchyma; the volunteers were divided into two groups (age ≤ 40 and age > 40) and the correlation between age and shear stiffness of parencbyma in each group were analyzed separately. Results The shear stiffness of whiter matter [(23.1±5.7) kPa] was higher than that of grey matter[(11.3±2.6) kPa], and the difference was significant (t = 19.34, P < 0.01). In male, the shear stiffness of WM and GM was (23.4±5.8) kPa and (11.4±2.8) kPa respectively; while in female, it was (22.8±5.6) kPa and (11.1±2.5) kPa respectively. No sex differences were found in the stiffness of white matter or gray matter (t = - 0.534, - 0.606, P > 0.05). An age-dependent trend was observed in the stiffness of grey matter(r =0.315, P < 0.01),while not in whiter matter (r = 0.183, P > 0.05). When the shear stiffness of subjects no more than 40 years old was analysed, the age-dependent trend of shear stiffness was found both in white matter and gray matter(r = 0.251,0.235, P < 0.05); While in subjects over 40 years old, the age-dependent rend of shear stiffness was not found in white matter or gray matter(r = 0.181, - 0.001, P > 0.05). Conclusions The shear stiffness of WM is significantly higher than that of GM. No obvious sex difference was found in the stiffness of brain parenchyma. The shear stiffness of GM increases with age; the age-related increase of shear stiffness of WM was only found in subjects under 40 years old.

Application of a new mismatch model on evaluating infarct core and penumbra in acute ischemic stroke using CT perfusion source images / 中华放射学杂志

Objective To assess the diagnostic value of determining infarct core and penumbra using CT perfusion source images (CTP-SI) mismatch model in hemispheric stroke less than 9 hours.Methods "one-stop shop" CT examination including non-contrast enhanced CT (NCCT), CTP, CT angiography (CTA) were performed in 24 patients with symptoms of stroke less than 9 hours.The Alberta Stroke Program Early CT Score (ASPECTS) were analyzed on arterial phase CTP-SI and venous phase CTP SI using Wilcoxon rank-sum test, then compared with the follow up imaging ASPECTS using multiple linear regression.Results The median (min-max) scores of ASPECTS on arterial phase CTP-SI, venous phase CTP-SI and follow-up imaging were 9.0 ( 2.0-10.0 ), 9.3 ( 6.5-10.0 ) and 9.0 ( 7.0-10.0 ),respectively. ASPECTS measured on arterial phase CTP-SI significantly differed from the ASPECTS on venous phase CTP-SI ( Z =-2.812, P = 0.005 ).Moreover, the linear regression analysis showed significant correlation between the ASPECTS on venous phase CTP-SI and follow up imaging ASPECTS ( Beta =0.715,P = 0.003 ).Conclusion CTP-SI mismatch model provides a method of choice in predicting penumbra and infarct core in hemispheric stroke.

Diagnostic value of CT perfusion source images in superacute stroke / 中华放射学杂志

Objective To investigate the diagnostic value of CTP-SI in acute stroke less than 9 hours.Methods In present study."one-stop shop"CT examination were performed in 34 patients with symptoms of acute stroke in le88 than 9 hours.We divided patients into two groups according to with and without delayed perfusion on CTP-SI.and compared ASPECTS (Alberta Stroke Program Early CT Score Study)scores on non-contrast CT(NCCT),arterial phase CTP-SI,venous phase CTP-SI with follow-up imaging.The ASPECTS were analyzed on arterial phase CTP-SI and veIlous phase CTP-SI using Wilcoxon rank-sum test.then compared with the follow up imaging ASPECTS using multiple linear regression.Results The median(min-max)scores of ASPECTS on NCCT,arterial phase CTP-SI,venous phase CTP-SI and follow-up imaging were 9.0(6.0-10.0),6.5(1.0-8.0),8.0(3.0-10.0)and 7.0(0-10.0)in group with delayed perfusion,respectively,and 9.0(1.0-10.0),8.5(1.0-10.0),8.5(1.0-10.0)and 8.0 (0～10.0)in group without delayed perfusion respectively.ASPECTs scores measured on arterial phase CTP-SI did not differ from venous phase CTP-SI in group without delayed perfusion ( Z = - 1.00, P =0.317), while there was significant difference in group with delayed perfusion (Z = -3.08, P = 0.002 ).There were significant correlation with ASPECTS scores measured on NCCT, arterial phase CTP-SI and venous phase CTP-SI to follow-up imaging ASPECTS (r =0.899,0.926,0.928,P ＜0.01 ) in group without delayed perfusion; ASPECTS measured in venous phase CTP-SI showed the best correlation to follow-up imaging ASPECTS (r = 0.762, P = 0.004) in group with delayed perfusion.Multiple linear regression showed that the correlation in only venous phase CTP-SI with foUow-up imaging ASPECTS was statistically significant:in group without delayed perfusion, Beta = 0.966, P ＜ 0.001 ; in group with delayed perfusion,Beta = 0.765, P = 0.004. Conclusion Presence of delayed porfusion in CTP-SI is quite important in identifying ischemic penumbra, which plays a critical role in imaging-guided thrombolytie therapy.

Combined Application of CT Perfusion and CT Angiography in Cerebrovascular Diseases / 中国康复理论与实践

@#Objective To study the clinical diagnosis value of the combination application of CT perfusion(CTP) and CT angiography (CTA) in cerebrovascular diseases. Methods 20 patients suspected of cerebrovascular diseases（CVD） were examined with CTP and CTA. All the CTA data were send to 3D post processing card for MIP, SSD and VR reconstruction. Perfusion data were analyzed by CT perfusion package. The absolute TTP, MTT, CBV, CBF values and the relative value between normal and pathological sides were calculated.Results Low perfusion which indicated the prophase of ischemia infarction were detected in 15 cases, 12 cases were located in MCA area, and 10 of them the stenosis of responsible arteries were demonstrated. The degree of the vessel stenosis can be evaluated exactly by CTA source images. Other 5 cases were located in the area of PCA and no positive detection in CTA examination.Conclusion Combined application of CTP and CTA can finish two examinations at the same time in the fast and economic way. Both the hemodynamics changing and the morphology of the vessels were demonstrated which providing omnidirectional pathophysiological information for clinical diagnosis and therapy.

Preliminary study of MR elastography in brain tumors / 中华放射学杂志

Objective To investigate the potential values of magnetic resonance elastography (MRE)for evaluating the brain tumor consistency in vivo.Methods Fourteen patients with known solid brain tumor(5 male,9 female;age range:16-63 years)underwent brain MRE studies.Informed consent was obtained from all patients.A dedicated external force actuator for brain MRE study Was developed.The actuator was fixed to the head coil.During scan.one side of the actuator was attached to the patients'head.Low frequency oscillation Was produced by the actuator and caused shear waves propagating into brain tissue.The pulse sequence used in the study Writs phase-contrast gradient-echo sequence.Phase images of the brain were obtained and the shear waves within the brain were directly imaged.Phase images were processed with local frequency estimation (LFE) technique to obtain the elasticity image.Consistency of brain tumors Was evaluated at surgery and Was classified as soft,intermediate,or hard with comparison to the white matter of the brain.Correspondence of MRE evaluation with operative results was studied.Results The elastic modulus of the tumor Was lower than that of white matter in 1 patient,higher inll patients,and similar in 2 patients.At surgery,the tumor manifested a soft consistency in I patient,hard consistency in 11 patients,intermediate consistency in 2 patients.The elasticity of tumors in 14 patients evaluated by MRE was correlated with the tumor consistency on the operation.Conclusion MRE Can noninvasively display the elasticity of brain tumors in vivo,and evaluate the brain tumor consistency before operation.

Imaging guided thrombolytic therapy in acute ischemic stroke: the value of magnetic resonance angiography / 中华放射学杂志

Objective To evaluate the value of MR angiography in thrombolytic therapy of acute ischemic stroke. Methods According to inclusion criteria, 65 patients who also having large vessel occlusion were selected, and they were performed rt-PA treatment (38 patients) and routine treatment (27 patients) within 3-6 hours of onset of symptoms, respectively. Mann-Whitney U test and chi square test were performed to compare the clinical and MR imaging baseline index and the clinical outcome between the two groups respectively. Clinical outcome was assessed after 3 months using a dichotomized modified Rankin scale score.Data were also compared with the combined analysis of the ATLANTIS, ECASS, NINDS rt-PA trials. Resets The difference of clinical outcome in 3 months between the two groups was significant (P < 0. 05) and the median of the two group was 1 and 3, respectively. The ratio of favorable outcome (mRS 0-1) in the two groups was 52. 6% (20/38) and 33.3% (9/27), respectively. Conclusion MR angiography plays an important role in thrombolytic therapy of acute ischemic stroke and it should be used to consummate the conventional inclusion criteria, the patients with large vessel occlusion should be treated by rt-PA.

In vive MR evaluation of the vessel wall shear stress in the common carotid artery / 中华放射学杂志

Objective To apply a non-invasive and feasible method for the quantification of local wall shear stress (WSS) in vivo using magnetic resonance imaging. Methods The fight common carotid artery of a young healthy male volunteer was examined using cine phase-contrast MR sequence. The cross- sectional area, average flow velocity, maximum velocity and flow rate were obtained. Three dimensional paraboloid model was applied to measure WSS value at common carotid artery. Results The mean/peak WSS was (0.75±0.41)N/m2 for the common carotid artery; The mean (range) velocity was (23.4± 12.0) cm/s; The mean (range) luminal vessel area was (32.2±2.9) mm2; The blood flow rate was (7.8±4. 6) ml/s; Conclusion WSS's magnitude, distribution and changes can be determined by MR imaging combining with the three-dimensional paraboloid method.

Measurement and analysis of geometric parameters of human carotid bifurcation using image post-processing technique / 中华放射学杂志

Objective To investigate variation in the carotid bifurcation geometry of adults of different age by MR angiography images combining image post-processing technique. Methods Images of the carotid bifurcations of 27 young adults (≤40 years old) and 30 older subjects ( >40 years old) were acquired via contrast-enhanced MR angiography. Three dimensional (3D) geometries of the bifurcations were reconstructed and geometric parameters were measured by post-processing technique. Results The geometric parameters of the young versus older groups were as follows: bifurcation angle (70.268°± 16.050° versus 58.857°±13.294°), ICA angle (36.893°±11.837° versus 30.275°± 9.533°), ICA planarity (6.453°±5.009° versus 6.263°±4.250°),CCA tortuosity (0.023°0.011 versus 0.014± 0.005), ICA tortuosity (0.070±0.042 versus 0.046±0.022), ICA/CCA diameter ratio (0.693± 0.132 versus 0.728±0.106), ECA/CCA diameter ratio (0.750±0.123 versus 0.809±0.122), ECA/ ICA diameter ratio (1.103±0.201 versus 1.127±0.195), bifurcation area ratio (1.057±0.281 versus 1.291±0.252). There was significant statistical difference between young group and older group in bifurcation angle, ICA angle, CCA tortuosity, ICA tortuosity, ECA/CCA and bifurcation area ratio (F= 17.16,11.74,23.02,13.38,6.54,22.80,respectively, P<0.05). Conclusions MR angiography images combined with image post-processing technique can reconstruct 3D carotid bifurcation geometry and measure the geometric parameters of carotid bifurcation in vivo individually. It provides a new and convenient method to investigate the relationship of vascular geometry and flow condition with atherosclerotic pathological changes.

Investigating effect of fusion gene therapy by MR diffusion-weighted imaging in a rat C6 glioma model / 中华放射学杂志

Objective To evaluate the use of diffusion-weighted imaging(DWI)for early detection of tumor response to Angiostatin-Endostatin(Statin-AE)fusion gene therapy in a rat C6 glioma model.Methods Fifty male wistar rats with C6 tumor cells implanted into the striatum were examined by a 3.0T MR scanner,then the rats beating tmors were divided into two groups,treatment group and control group.Rats in the treatment group received 107 plaque forming unit(pfu)recombinant herps simplex viral (R-HSV)mediated Statin-AE fusion gene therapy on day 7,and then the tumors were conformed on MRI.Conventional MR and DWI examination were acquired on 1,2,3 weeks after implantation with a 5-inch surface coil.Two(1 w),eight(2 w)and all the residual rats(3 w)of each group were sacrificed to perform the histopathological examination after each MBI examination.Pretreatment and post treatment tumor volulnes and apparent diffusion coefficient(ADC)values were calculated.Rank sum test and t test were employed for statistical analysis.Results On MRI,43 rats demonstrated tumors on day 7 with a successful rate of 86%,On week 2,the tumor volumes of the controh and treatment group were 90.6 and 91.64 mm3,with no significant difference(Z=-0.14,P＞0.05).On week 3,the tumor volumes of the controls and treatment group were 156.64 and 29.64 mm3,and a significant difference was observed(Z=-3.45,P＜0.01).On week 2.the ADC values of the tumor centers of the treatment group and the control group were (1.20±0.25)×10-3 and(0.99±0.08)×10-3 mm2/s,and the values of the tumor peripheral parts of the two groups were(1.00±0.25)×10-3 and(0.83±0.12)×10-3mm2/s,the ADC values of both tumor centers and peripheral parts of the treatment group were significantly higher than those of the control group (t=-0.82 and-0.46,P＜0.05).On week 3,the ADC values of the tumor centers of the treatment group and the control group were(0.92±0.21)× 10-3 and(0.99±0.09)×10-3mm2/s,and the values of the tumor peripheral parts of the two groups were(0.81±0.19)×10-3 and(0.78±0.11)×10-3 mm2/a,there were no statisfical difference between the two groups(t=0.82,and-0.46,P＜0.05).HE stained slices showed more prominent tumor interstifial edenla.swelling and death of tumor cells in the treated rats than the controls.Conclusions Combination of conventional MRI and DWI can be powerful to monitor tumor progression and therapy effecL Conventional MRI showed that the therapy slow the tumor progression in size while DWI demonstrated the tumor response even earlier than size change.DWI has potential use forthe detection of early response to antiangiogenic gene therapy.

Possibility of three-dimensional time-of-flight magnetic resonance angiography as a reliable screening tool for evaluation of intracranial vascular stenosis and occlusive disease prior to stent implantation / 中国组织工程研究

AIM: To investigate whether three-dimensional time-of-flight magnetic resonance angiography (3D TOF MRA) can be used as a reliable screening tool for evaluation of intracranial vascular stenosis and occlusive disease before stent implantation. METHODS: Thirty-three patients with suspected intracranial arterial stenosis received 3D TOF MRA and digital subtraction angiography (DSA) examinations in Chaoyang Hospital Affiliated to Capital Medical University between March 2007 and April 2008,and were included for this study. Two physicians blindly estimated stenosis,patient history,and clinical information of 363 vascular segments from 33 patients,including bilateral internal carotid artery (ICA),anterior cerebral artery (ACA),middle cerebral artery (MCA),posterior cerebral artery (PCA),vertebral artery,and basilar artery (BA). Stenosis was categorized as 30%-49%,50%-69%,70%-99%,and 100%. For each kind of stenosis,sensitivity,specificity,positive predictive value,negative predictive value,K and P values of MRA were calculated,respectively,as compared to DSA. RESULTS: A total of 42 diseased vascular segments were identified. Compared to DSA,for intracranial stenosis 50%-69%,3D TOF MRA showed sensitivity 100%,specificity 96.8%,positive predictive value 62.1%,negative predictive value 100%,K value 0.751,and P value 0.000; For intracranial stenosis 70%-99%,the corresponding value was 100%,98.6%,70.6%,100%,0.821,and 0.000,respectively; For intracranial stenosis 30%-49%,it was 25.0%,99.7%,66.7%,98.3%,0.356,and 0.000,respectively.CONCLUSION: For high sensitivity and specificity to intracranial stenosis 100%,70%-99%,or 50%-69%,compared to DSA,3D TOF MRA is a reliable screening tool for preoperational evaluation of intracranial vascular stenosis and occlusive disease.