MR-T1ρ imaging is one of the novelest MRI techniques in recent years,T1ρ relaxation mainly reflect the interaction between water molecules and the surrounding macromolecu]es.Due to the unique point of view,the technique has been used to investigate a variety of pathological mechanisms in early stage of diseases,such as the content of collagen protein in articular cartilage,neuron apoptosis in neurodegenerative diseases and so on,which provides a new tool for detecting lesions in ultra-early stage or the evaluation of treatment effect.

The research of hemorrhagic transformation (HT) after cerebral infarction is now focus on HT after thrombolytic therapy. However, attention should also be aroused to the occurrence of spontaneous HT in most patients who cannot receive thrombolysis promptly because of various reasons, for it has important influence on the treatment of cerebral infarction and prognosis. This article reviews the concept, typing, pathogenesis, correlation factors, imaging diagnosis and prediction of HT, as well as the effects of non-thrombolytic therapies on HT, such as antiplatelet, defibrase, anticoagulant, anti-free radical, and the relations between HT typing and prognosis.

Objective To investigate the hemodynamics of basilar artery and its blood-supply area in patients with vertigo by 3.0 T MR.Methods Fifty patients with vertigo were selected as case group and 50 healthy volunteers were selected as control group.All subjects in the case group and in control group were examined by brain magnetic resonance imaging (MRI),magnetic resonance angiography(MRA),fast cine phase contrast(Fast CINE PC) and flow-sensitive alternating inversion recovery sequence (FAIR).After image postprocessing,the velocity and the blood flow volume of basilar artery were measured and calculated.The FAIR value of bilateral occipital lobe,cerebellum,pons and medulla oblongata was measured.Statistical testing was performed.Results The average velocity,peak velocity and blood flow volume of the basilar artery in case group were significantly lower than those in the control group(the average velocity:(22.47 ±9.14) cm/s vs (31.41 ±5.97) cm/s,t =-5.79,P ＜ 0.0001 ; peak velocity:(31.60 ± 13.18) cm/s vs (44.00 ± 7.84) cm/s,t =-5.71,P ＜0.0001 ;blood flow volume:(91.14 ±43.92) ml/min vs (127.49 ± 28.33) ml/min,t =-4.92,P ＜0.0001).The perfusion of the posterior circulation in the case group was lower than that in the control group ((882.35 ±35.22) vs (906.34 ±36.82),t =-3.33,P =0.0012).The average velocity,peak velocity and blood flow volume of the basilar artery in case group whose brain parenchyma and blood vessels were normal were (26.31 ±5.16) cm/s,(36.33 ±6.60) cm/s,(95.38 ±28.16) ml/min respectively,which were all less than those in the control group (average velocity:t =-2.72,P =0.0086 ; peak velocity:t =-3.12,P =0.0027 ;blood flow volume:t =-3.53,P =0.0008).The perfusion of the basilar artery blood-supply area in case group whose brain parenchyma and blood vessels were normal was (904.00 ± 35.82),there was no difference when compared with the control group (906.00 ± 36.82,t =-0.20,P =0.8427).Conclusion Whether the brain parenchyma and blood vessels is normal or not,the velocity and blood flow volume of the basilar artery in patients with vertigo are decreased,but the perfusion of the basilar artery blood-supply area are different,it depends on whether there is ischemia.

Objective To establish a stable model of intraluminal thread approach in making focal cerebral ischemia/reperfusion modelin rabbit.Methods Forty New Zealand white rabbits were randomly divided into three groups:A,B,and C.Angiography of ICA wasperformed in group A(n=5). Control group B(n=5) was sham-operated.In group C(n=30),the focal cerebral ischemia/reperfusionmodel was made by inserting a wire ( d=0.45 mm ) into MCA through ICA and CCA directly and pulling it out 3 hours later . MRI andneurological deficit score were used to evaluate the effectiveness of models.Results Angiography could show the course and bifurcation of ICA clearly.22 models were successful.The pathological changes were shown on MRI.The neurological deficit score (reperfusion 1 h) were 2.8?0.45.Conclusion The focal cerebral ischemia/reperfusion model made by inserting a wire(d=0.45 mm) into MCA through ICA and CCA directly and pulling it out 3 hours later was stable and fit for imaging research.

Objective To study the effects of basic fibroblast growth factor (bFGF) and Gingkgo biloba extra(GbE) on experimental cerebral infarction. Methods 40 healthy adult cats were equally devided into group A with sodiumchloride, group B with bFGF, group C with GbE and group D with bFGF+GbE in random.All animals were operated to establish the feline models of cerebral focal ischemia-reperfusion by the approach of left transorbital. The certain madicine intervene were take at 0 h,24 h,48 h after the models established.The neurological defects score was evaluated by Philips' criteria score in 1 d and 7 d. The physiological changes were observed by HE stained and electron microscope.Results The neurological defects score was singificiant lower in D group(41.50?8.18) than that in group A(82.20?8.08),B(63.60?6.22) and C (61.00?6.58)(allP

Objective To evaluate the utility of diffusion-weighted MRI(DWI)and the correlation between the abnormalities in DWI and the clinical factors in patients with transient ischemic attack of the brain(TIA).Method Clinical,conventional MRI,and DWI data were collected on 59 consecutive patients with TIA between March and July 2006 within 7 days of the onset of TIA symptoms.The relationship between DWI-detected findings and patients' clinical manifestations was then analyzed.Results DWI-detected abnormalities were displayed in 22 of 59 cases(37%,positive group).Prolonged TIA duration(TIA duration≥30 minutes),repeated episodes,motor deficits,aphasia,history of either stroke or TIA,diabetes mellitus,and atrial fibrillation were observed more frequently in the positive group than in the negative group.In 9 of 22 cases,the identified lesions were not detected by conventional MRI(T2-weighted imaging or fluid-attenuated inversion recovery).In other 13 cases,abnormalities were present on both DWI and conventional MRI.Conclusions In TIA patients,prolonged TIA duration(TIA duration≥30 minutes),repeated episodes,motor deficits,aphasia,history of either stroke or TIA,diabetes mellitus,and atrial fibrillation were significantly correlated with detectable abnormalities on DWI.

Objective To observe the diffusion characteristics and pathology changes with DTI in rabbit models with mild cerebral contusion and laceration (CCL). Methods Thirty rabbits were randomly selected and made into models of mild CCL by free fall, while other 10 rabbits were cut only in the skull as control. T2WI and DTI were performed 1, 3, 6, 12, 24, 48 and 72 h after the operation. DTI value of average diffusion coefficient (DCavg) and fractional anisotropy (FA) of mild CCL and its peripheral area were measured and compared. Histological examination was also performed. Results One hour after operation, CCL area showed high signal on T2WI, and no abnormal signal was found in the peripheral area, but both had abnormal color on DTI map. T2WI signal intensity in peripheral area of 22 rabbits (73.33%) increased gradually and had much abnormal color on T2WT map after 3 h. There was significant difference of FA and DCavg between CCL and the mirror region, the peripheral area and the mirror region (P<0.05). The value of FA decreased slightly since 12 h. More prominent tissue necrosis, edema and hemorrhage were found in CCL area than in the peripheral area with pathology examination. No abnormal manifestations of the brain were detected with both pathology and MR examination in the control rabbits. Conclusion DTI is sensitive for detecting mild CCL and can show it directly on color map, and thus may be used as a routine examination in the evaluation of mild CCL.

Objective To evaluate the clinical and MRI features of choroid metastatic tumors.Methods Clinical and MRI findings in 4 cases with choroid lung carcinoma metastasis based on pathological results were retrospectively analyzed.Results Lung metastatic carcinomas were the most common primary cancers metastasizing to the choroid all the 4 cases had a decrease of visual acuity rapidly.MRI showed diffuse or local thickness of bulbar wall,and revealed T 1 isointense and T 2 iso-or hyperintense signals.A mass extruding into the bulb was seen in 1 patient.Conclusion MRI of choroid metastatic carcinoma has characteristic manifestations,and MRI is an effective and useful technique for the diagnosis of this lesion.

Objective To observe the effect of NGF on the caspase-12 in cerebral ischemia/reperfusion. MethodsTwenty-six healthy male white rabbits were randomly divided into sham, ischemia/reperfusion and NGF group. The tissues were sampled to detect the expression of caspase-12, caspase-3 by immunohistochemistry, and to detect the cerebral apoptosis by flow cytometry and TUNEL staining methods.Results Compared with sham group, the expression of caspase-12 and caspase-3 in I/R group was higher (P

Objective To evaluate the changes of cerebral perfusion and hemodynamics in the patients with mono-carotid artery stenosis after stenting with the technique of DSA parametric imaging. Methods 15 patients with mono-carotid artery stenosis(the stenosis>75%) undergone carotid stenting were choosed. Digital subtraction imagines of diplo-carotid arteries were acquired before and after operation, then the imagines were processed by special soft ware in personal computer. The region of interest (ROI)were selected in the brain,internal carotid artery and superior sagittal sinus separately, the time-gray scale curves of the ROIs were drawn with the soft ware, from which,then acquired the following parameters from the time-gray scale curves,the largest gray values of brain in disordered side pre-and post-operation, and the parameters including peak value (PV), mean transit time (MTT) ,time to peak (TP), time of appearance to the peak , the max slope rate of the curve and relative time of cerebral circulation were also evalua-ted, respectively. The imaging speed was 7.5 pictures per second. The results were statistically evaluated by using matched-t test. Results Before the stenting, the values of the parameters peak value, the max slope rate of the curve,TP,MTT,relative time of cer-ebral circulation were 108.20±5.58 , 1.23±0.37 , (4.78±0.24)s , (8.20±0.42)s and(4.92±1.03)s , respectively; after the stenting , the values of the parameters above-mentioned were 114.20±7.58, 2.01±0.36, (4.14±0.40)s, (3.55±0.56)sand(4.18±0.89) s , respectively, the difference of the parame-ters above-mentioned pre-and post-operation were statisti-cally significant (t=5.97 , 8.00 , 0.21 , 10.21 , 10.12 and 4.14,P<0.05). Before and after operation, the values of time of appearance to the peak were (5.39±0.24) s and)(5.37±0.78) s , respectively , there was no statistical significance (t=0.21, P> 0.05). Conclusion DSA parametric imaging can be used to evaluate the changes of cerebral perfusion and hemodynamics before and after arterial stenting.