Objective To examine the intracranial lesions before and after operation by functional MRI with BOLD technique, and to map the brain activation images of the patients on general MR images. Methods Thirty one patients had lesions involving the frontal and/or parietal lobes in one side of the cerebral hemispheres, and the lesions included 29 tumors (11 gliomas; 13 metastases; 5 meningiomas) and 2 infections. MSEPI technique was performed with four scan planar parallel AC PC. During each scan series, the patients were asked to perform repetitive finger thumb opposition movement in the same period of active and rest duration. All the scanning data were transferred to a workstation and dealt with statistical method. The patients had been examined again by the same sequence protocol postoperatively, and the fMRI images were analyzed and compared with that of the preoperation fMRI. Results The motor cortex of both cerebral hemisphere was asymmetrical, and the border between the motor cortex and lesions could be clearly identified in all of the patients preoperatively. After operation, both sites of the motor cortex were nearly replaced. Conclusion fMRI was very useful in evaluating the surgical planning and the prognosis of the patients.

Objective To analyse the imaging characters of intracranial malignant teratomas (IMT). Methods The imaging appearances of IMT were analyzed in 15 pathologically proved IMT. MRI were performed on all the 15 cases, CT on 8 of them. Results Thirteen IMT showed as a lobular cyst solid mass with clear borders. The solid portion of IMT displayed iso (6/13) to hypointense(7/13) on T 1WI and iso (2/13) to hyperintense(11/13) on T 2WI. The heterogeneous enhancement was found in 11 cases, homogeneous in 2. Two IMT exhibited as the intrasellar solid lesions involving thalamencephalon. Calcification was found in 8 IMT on CT scan. No fat was demonstrated in the tumor on both CT and MR. Conclusion IMT displays relatively typical appearances on imaging studies. Together with the CT scan, The MR study may make the diagnosis before the operation.

ObjectiveTo describe the MR features of Rasmussen encephalitis (RE).Methods The MRI of 10 pathologic confirmed patients (7 male,3 female,mean age 11 ± 4 years) with RE were retrospectively analyzed in this study.Routine axial,sagittal and coronal (perpendicular to the oblique long axis of the hippocampus) scans were obtained for T1WI,T2WI and fluid-attenuated inversion recovery (FLAIR)images. The location and degree of cerebral atrophy,gray matter signal changes,and the evolution of these findings were evaluated. Results Brain atrophy included the enlargement of lateral ventricle(8/10),temporal horn (9/10)and lateral fissure (9/10); widened sulci and small gyri in the isolateral hemisphere (7/10) ; atrophy in caudate and putamen nucleus (6/10).The cortical atrophy was extensive at late stage of the RE,and usually was hemispheric or involved more than two lobes.The signal changes included hyperintensity involving extensive cortical and/or subcortical regions (9/10). The follow-up MR study demonstrated the progression of brain atrophy and extensive signal changes.Conclusions RE usually presents in pediatric patients. The imaging findings included progressive unilateral brain atrophy,enlargement of lateral ventricle,lateral fissure and sulci,and small gyri with or without cortical T2hyperintensity.Deep nucleus atrophy may be involved in RE.

Objective To study the MRI findings of intracranial hemangiopericytomas. Methods The MRI in 27 pathologically proved cases of intracranial hemangiopericytomas were retrospectively reviewed.Results The MRI characteristics of intracranial hemangiopericytomas were as follows: (1) The tumors appeared mainly iso- and hypointense with cortical gray matter on T 1-Weighted images and iso- and hyperintense on T 2-Weighted images. The hyperintense on T 1-Weighted images and hypointense on T 2-Weighted images were unusual observed in tumors. After contrast injection,the lesions usually enhanced markedly and heterogeneously. (2) The tumors tended to be irregular multilobulated in shape. (3) More than half tumors were narrow-based dural attachment. (4) Multiple signal voids of vessel in tumors were often observed,but intratumoral calcification was not present. (5) Bone erosion was present,but hyperostosis was not present.Conclusion The MRI appearances of intracranial hemangiopericytomas are characteristic. It is helpful to get a correct diagnosis with clinical features.

Objective To analysis the imaging appearances of giant intracranial aneurysms(GIA).Methods Forty pathological proven GIA were included in this study.Results The MR appearances were variable depending on the present of thrombosis,the size and age of the thrombosis,and the secondary changes of the GIA.The typical flow void presented in majority patients.The flow artifacts were displayed across the residual lumen in the phase direction of MR image.The residual lumen showed dense contrast enhancement.The thrombosis was found in 26 GIAs with variable signal intensity from homogeneous hypo-or hyperintensity to onion or turbo like heterogeneous signal intensity without contrast enhancement.DSA studies displayed residual lumen of GIAs and fail to display totally thrombosis GIAs.Conclusion MR studies clearly show the residual lumen and thrombosis of GIAs.MR study is an important conjunctive tool of the DSA studies in diagnosis GIA.

Objective To explore the correlations of the MRI findings and its pathological typing in the focal cortical dysplasia (FCD) .Methods MR images of 74 patients with FCD confirmed by operation and histopathologic examination were analysed retro‐spectively .MRI findings with FCD were divided into three subtypes including radial band type ,hyperintensity type and mild type . The correlation of the FCD MRI findings and pathological typing is analysed .Results In 74 patients with FCD ,there were radial band type in 12 cases ,hyperintensity type in 32 cases ,and mild type in 30 cases respectively .M RI finding of radial band type FCD showed a tail of increased T2WI/FLAIR signal tapering down to the lateral ventricle .Hyperintensity type FCD showed increased T2 WI/FLAIR signal in the cortex and subcortical white matter ,accompanied with focal cortical thickening .Mild type FCD showed T2 WI/FLAIR subtle hyperintense signal in cortex with or without focal cortical thickening ,but there was no hyperintense signal in subcortical white matter .Most of radial band type FCD were ⅡB in pathology .Most of hyperintensity FCD were ⅡA and ⅡB .Mild type FCD was more found to beⅠA orⅠB .Conclusion Analysing MRI features would improve the accurate diagnosis of FCD and help to infer the pathological type .

DWI), and 10 patients(22 7%)without (PWI=DWI) The remaining 11 patients (25 0%) who were diagnosed as having TIAs The mismatch tissue of MTT and DWI had statistical significance in definiting penumbra, P 0 05 DWI was normal or presenting dot or snip high signal in TIAs patients Conclusions Application of PWI and DWI is helpful in detecting penumbra and guiding thrombolytic therapy in acute ischemic stroke By combining DWI with clinical symptoms, TIA should be excluded Hence, it might save the poor outcome from blind thrombolysis and huge consumptions on economic and human resources

Objective To determine MR manifestations and pathologic types of benign meningiomas and their relationship with tumor recurrence.Methods There were 218 patients (160 females,58 males; age range 4-79 years) with benign meningiomas in the study,including 31 recurrent meningiomas (recurrence group)and 187 primary meningiomas (primary group).All patients were proved by postoperative pathology.Differences of pathological types and MRI manifestations between the recurrence group and the primary group were evaluated by using x2 test and rank sum test.Logistic regression analysis was performed by taking tumor recurrence as the dependent variable,and age,gender,vital structures involvement and pathologic types as independent variables.The recurrent time intervals were compared by rank sum test.Results There were 30 patients with intracranial vital structures involvement or extreintracranial communication tumors in the recurrent group,which was obviously higher than that of the primary group (61 patients).The difference was statistically significant (x2 =57.672,P =0.001).The tumors located in the skull-base and juxtasinus in the recurrent group were obviously more than those in the primary group,and difference was statistically significant (x2 =10.990,P =0.001).Multi-logistic regression analysis showed that the recurrent risk of benign meningiomas was elevated significantly only with vital structure involvement or extre-intracranial communication tumors (wald x2 =31.863,OR =3.820,P =0.001).The recurrent risk of dural sinus involvement was 3.820 times of cerebral artery trunk and cranial nerves involvement,and the risk of the latter was 3.820 times of the non-involved.There was no statistical difference between the two groups in pathology type,location,peritumoral edema,tumor morphology and tumor size.The relapse time of dural sinus involvement and cerebral artery trunk involvement in the recurrent group was 24(13 to 180) and 126(12 to 187) months,respectively.There was significant difference (Z =2.197,P =0.028).Conclusions It is more common that the recurrent benign meningiomas located in the skull base and juxtasinus.The recurrent risk significantly increases when benign meningiomas with vital intracranial structure involved or with extra-intracranial communication tumor.The relapse time of dural sinus involvement is possibly shorter than that of cerebral artery trunk involvement.MRI plays an important role in predicting tumor recurrence and prognosis of benign meningiomas.

OBJECTIVETo evaluate the value of perfusion MR imaging and angiographic evidence of collateral circulation in symptomatic patients with ischemic cerebrovascular diseases (ICVD).

METHODSCerebral angiography and perfusion MR were performed in 16 patients with symptoms of ICVD. Qualitative perfusion maps were calculated for regional cerebral blood volume (rCBV) and mean transit time (MTT).

RESULTSA total of 27 lesions were seen on the perfusion MR maps (6 infarcts and 21 ischemic lesions) and most of them (26/27) showed a prolonged MTT. MTT is sensitive to the presence of ischemic lesions, but not sufficient in distinguishing infarct from ischemia. All of the infarcts showed a decreased rCBV, while most of the ischemic lesions showed a normal or increased rCBV. When collateral circulation was identified on angiography, most ischemic lesions were not infarcts and had a normal or increased rCBV. The absence of angiographically identifiable cerebral collaterals may not always result in an infarct; 50% had decreased rCBV. Despite the absence of angiographic collaterals, the other half had normal or increased rCBV.

CONCLUSIONCerebral angiographic evidence of collateral circulation is important in identifying a favorable outcome in patients with ICVD. However, a lesion with a normal or increased rCBV suggests a sufficient collateral circulation even without angiographic collaterals. Perfusion images may be a potentially useful adjunctive tool in the prediction of the outcome of ICVD, particularly where no apparent collateral macrocirculation is seen on CA.

Adult ; Aged ; Aged, 80 and over ; Brain Ischemia ; diagnosis ; physiopathology ; Cerebral Angiography ; Cerebral Infarction ; diagnosis ; Cerebrovascular Circulation ; Collateral Circulation ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged

Objective To investigate the MRI classifications and imaging findings of dysembryoplastic neuroepithelial tumor(DNET). Methods MR images of 34 patients with pathologic confirmed DNET of Beijing Sanbo Brain Hospital were retrospectively reviewed in this study. The classification was made according to the number of pseudocysts, scope of involvement, morphology and location. Results MRI appearances of DNET were divided into three subtypes: cystic‐like, polycystic‐like and diffuse type. Twelve cases had cystic cortical, including front lobe (5 cases), temporal lobe (5 cases), parietal lobe (2 cases). These cases presented quasi‐circular or oval shape, with hypointense on T1WI and strongly hyperintense on T2WI. T2‐FLAIR was observed hyperintense ring sign in the tumor periphery and the cystic content was close to CSF but having the largest difference to that of CSF, which signal was higher than CSF. Twenty cases were polycystic‐like, front lobe (7 cases), temporal lobe (7 cases), parietal lobe (5 cases), occipital lobe (1 case). In these 20 cases, they had slightly hypointense on T1WI and strongly hyperintense on T2WI. Located in the cortex and subcortical matter, with wedge shape, gyriform or triangle shape.On T2‐FLAIR, internal septation and hyperintense"ring sign"were observed. Two cases were diffuse type, bilateral (1 case), unilateral (1 case). In these 2 cases, diffuse lesions involving multiple areas with hyperintense ring and internal septation on FLAIR, including subcortical white matter, deep nucleus and periventricular area. Conclusions The MR appearances of DNET are variable. Understanding the MR imaging type of DNET might improve the MR diagnosis of DNET.