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 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 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 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 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 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 explore the dynamic changes of diffusion tensor imaging(DTI) in spinal cord of goats with persistent compression injury. Methods Eighteen goats weighted 20--25 kg were divided into three groups with completely random design: A, B and C. A balloon catheter was inserted into the epidural space at C3-4 level via intervertabral foramen for each goat. The balloon was inflated by injection of variable volumes of saline in group A and B 10 days following operation. The volume of saline was 0. 3 ml in group A and 0. 2 ml in group B,respectively. The compression sustained for 40 days. Group C served as uncompressed control without injection of saline. The locomotor rating score was applied to each group. Conventional MRI and DTI were performed. The apparent diffusion coefficient (ADC)and fractional anisotropy (FA) values were measured. Histopathological assessments of the compressed spinal cord were performed 50 days following operation with light microscope and transmission electron microscopy. Results Before operation, the locomotor rating score was 5, the ADC value was ( 1.23 ± 0. 05 ) × 10-3 mm2/s and the FA value was (0. 72 ± 0. 05 ) each group. Of six goats in Group A, the locomotor rating score severely decreased and reached( 1.5±0. 4)on the 40 th day after compression. The ADC value at compression site decreased soon and reached the minimum (0. 75±0. 04) × 10-3mm2/s on the 5 th day after compression. Then the ADC value increased gradually, restored normal on the 10 th day or so, then became markedly higher than normal and reached( 1.61±0. 05) × 10-3mm2/s on the 40 th day. The FA value at compression site decreased soon, reached(0. 54±0. 04)on the 1st day, then decreased gradually and reached(0. 43 ± 0.05) on the 40 th day. It appeared high signal intensity on T2WI on the 10 th day. In Group B, the locomotor rating score was moderately decreased and reached(3.4±0. 5 )on the 40 th day. The ADC value at compression site decreased slightly firstly, reached( 1.08±0. 04) × 10-3mm2/s on the 1st day, restored normal on the 20 th day or so, then increased gradually, became higher than normal and reached ( 1.27 ± 0. 05) × 10-3mm2/s on the 40 th day. The FA value increased slightly firstly, reached (0. 78±0. 05 )on the 1st day, then decreased gradually, restored normal on the 15 th day or so, became lower than normal and reached(0. 67±0. 05) on the 40 th day. There was no abnormality on conventional MRI. In Group C, the locomotor rating score, ADC value and FA value remained unchanged. There was no abnormality on conventional MRI. There were dynamic changes over time of the ADC value and FA value in Group A and B, which was more marked in Group A than that in Group B ( repeated measurements analysis of variance, F=426. 7 for the ADC value and F =7895.2 for the FA value, P < 0. 01 ). Histopathologically, swelling and degeneration of axons and neurons as well as the disarrangement of myelin sheathes could be seen. The pathological changes were more marked in Group A than in Group B. In Group C, no abnormality could be seen. Conclusion There are dynamic changes of DTI in cervical spinal cord with compressive injury that correlated with the degree and duration of compression. The ADC value decreased firstly, restored normal and then increased. The FA value increased firstly, restored normal and then decreased in mild compression while solely decreased in serious compression.