Objective To explore the clinical promise of CT 3D reconstruction of tracheobronchial tree(TBT) by analyzing 73 cases retrospectively. Methods All the 73 cases were collected from October 1997 to February 2000, who were scanned by EBCT with 130 kV and 630 mA. The scanning method was continuous volume scan, the slice thickness were 3 mm or 1.5 mm. All cross-sectional images were transmitted to the INSIGHT workstation and reconstructed with SSD (shaded surface display), and the threshold setting were -500 to -300 HU. Results 3D reconstruction of TBT with EBCT could reveal the abnormal changes of TBT by many kinds of diseases including central cancer, inflammation, bronchiectasis, saber-sheath trachea, trachea cancer, congenital disorders, post-surgical changes of lung cancer, and stenoses by adjacent benign or malignant diseases. It could be used to locate the stenoses and measure stenostic extent. Of the 35 central cancer cases with 3D reconstruction, 6 cases were pestle obstructed, 15 cases cone obstructed, 5 cases interrupted irregularly, 8 cases with eccentric stenoses, and 1 case with right stem destroyed and right upper lobe bronchus obstructed. Conclusion 3D reconstruction of TBT has characteristic sign in the diagnosis or differential diagnosis of central airway′s benign or malignant stenoses, and it is of instructional value in clinical use.

Objective To explore the MRI and pathologic characteristics of hippocampal sclerosis. Methods 16 patients with hippocampal sclerosis were examined with transvers and oblique coronal T 1 weighted,T 2 weighted and fluid attenuated inversion recovery(FLAIR) MR imaging. Results Of 16 patients,1 case had bilateral hippocampal sclerosis;15 cases were ipsilateral(left n =9,right n =6) proved by pathology.The MR features of hippocampal sclerosis were as follows:hippocampal atrophy present in all patients;hyperintensity on coronal FLAIR in all patients and on coronal T 2W images present on 15 sides; loss of superficial sulci hippcampal head seen in 11 sides;disruption of the internal structures present on 13 sides; atrophy of lateral white matter present on 7 sides; enlargement of the ipsilateral temporal horn present on 6 sides;atrophy of the ipsilateral temporal lobe seen on 2 sides. Conclusion Atrophy and hyperintensity on coronal FLAIR and T 2 weighted images were the most common features of hippocampal sclerosis and had positive diagnostic value. Combination of coronal FLAIR and T 2 weighted imaging could improve the diagnostic sensitivity and accuracy for hippocampal sclerosis.

Objective To evaluate the accuracy of MR diffusion weighted imaging (DWI) in the diagnosis of hyperacute cerebral infarction. Methods Twenty one patients with onset of strokelike symptoms underwent conventional MRI and DWI within 6 hours. Results DWI indicated cerebral infarction in 16 patients, all of whom had a final diagnosis of acute stroke. DWI was negative in 5 patients, all of whom had a final diagnosis of TIA. The abnormality seen at DWI was confirmed with follow up study. DWI had a sensitivity of 100% and a specificity of 100% in the diagnosis of hyperacute cerebral infarction, and conventional MRI interpretation yielded a sensitivity and specificity of 25% and 100%, respectively. Conclusion DWI is highly accurate in diagnosing hyperacute cerebral infarction and is superior to conventional MRI.

Purpose:To investigate the values of three newer contrast enhanced MRI sequences including gadolinium-enhanced FLAIR MRI(CE FLAIR), dynamic contrast-enhanced MRI (DCE MRI) and perfusion- weighted MRI(PWI) by comparing their advantages and disadvantages respectively in the diagnosis of intracranial tumors. Methods:43 patients with intracranial tumors underwent DCE MRI, CE FLAIR and PWI respectively. The gadolinium-enhanced FLAIR, dynamic enhanced MR and perfusion-weighted MR images were evaluated independently by two radiologists for the number of examinations with one or more enhancing lesions, the number and location of enhancing lesions per examination, the detectability for different lesions in different locations, size and extent of the lesions. Results:Perfusion-weighted MR images showed poor quality and could not give a diagnosis in 5 of 43 cases because of heavy susceptibility artifacts. There were 47 lesions in the 38 cases. However, 41 lesions were found on CE FLAIR MR images and 42 on DCE MRI and 45 on PWI. 3 lesions(2 located in the subcortical area and 1 in paraventricle) were only revealed on the CE FLAIR images. 4 lesions in the basal ganglia area were only found on dynamic enhanced images. 7 lesions in the cerebral hemisphere were only found on perfusion-weighted images. So there were significant differences in revealing lesions of different locations with the three MR modalities(P

Objective To assess the clinical history and MRI findings of pituitary adenoma of different hormonesecreting type.Methods We retrospectively studied 200 postoperated patients,from 1996 to 2000,who all had the preoperated MRI exams.All cases had histopathological evalutions.Both clinical presentation(age,sex,symtom,sign)and MRI findings(size,form,signal intensity,extension)were investigated.Results There was a great span of age with sixty percent owing for 35～55 years old.The male and female proportion was 1∶2 in PRL hormone-secreting pituitary adenoma.12 cases with luleinizing hormone-secreting and 2 cases with thyrotropin hormone-secreting pituitary adenoma were just male.In other types the incidences were similar in man and woman.Clinical symptom and sign present overlapping.The volume of tumor was from 0.5 cm?0.8 cm?1 cm to 6 cm?7 cm?8 cm with most multihormone adenoma's maxium dimension out of 5 cm.The signal intensity was not characteristic pre-and post-enhancement.No calcification could be seen.In term of extension,most was to suprasellar,then infrasellar,unilateral or bilateral sinus cavernous,last was to lower part of the third ventricle.Conclusion Different hormonesecreting pituitary adenomas have some speciality in clinical and MRI presentation.Although an accurate diagnosis can not be made according to it,more information have been obtained.

Objective:To improve the CT and MRI diagnostic accuracy of intracranial atypical cavernous angiomas(ACA).Methods:We retrospectively analyzed CT and MRI appearances,operative and pathological findings of 12 cases with ACA.Of them,11 cases were seanned by CT,10 cases by MRI and 9 by both CT and MRI.Results:Of 12 cases:One case as located at the sella ,1 case was at the fourth ventricle,5 cases were located at the cerebral hemisphere,4 cases were located at the middle cranial fossa and 1 case was at the posterior cranial fossa.There was edema in 3 cases,1 case had cystic component and 4 cases had cerebral hemorrhage.The localized rate of ACA by CT and MRI was 100%,but 11 cases were misdiagnosis and 1 case did not made the qualitative diagnosis. Conclusion:The qualitative diagnosis of ACA have some difficulty,so that the emphasis should be on the analysis of the combination imagiology and clinic.

Objective To obtain magnetic resonance imaging(MRI) symptoms that could be used in medical diagnosis and identification by analyzing the diverse MRI appearance of brain multiple sclerosis(MS).Methods MRI findings of 41 samples of clinically definite MS, including the numbers, distributions, sizes, and shapes of the lesions were analyzed. The symbolic characteristics and enhanced expression are also covered.Results Brain MS might happen singly and multiply, and more frequently with multiple happening. In a multiple case, 4—15 lesions were observed the most. Some samples showed with diffuse lesions which were unable to be counted accurately presenting as a “dirty-appearing white matter”. The distribution of the lesions was observed most frequently at the two sides of periventricle, and following by the subcortical, corpus callosum, and brainstem. Only two lesions were observed at cerebrum. The size of most lesions range from a few millimeters to 2 cm, accounting for about 75% of the total samples. Lesions with size above 2 cm were seen seldomly, with the biggest one of 6—7 cm. According to the shapes and symptoms, lesions might be categorized as an acute and chronic ones. The acute lesions had a shape of oval or circle, with a swelling appearance, low signal of T_1WI, and isointensity or a slightly higher signal on the circle. T_2WI showed a high signal, with different increase and showing “core+lunar” sign. This kind of lesions showed an enhancement with the circle enhancement as the most typical one, which had a complete circle or non-conplete arc shape enhancement, even the big lesions. The chronic lesion might also be divided into two categories. One was the quasi-symmetric lesion, with the distribution along two sides of periventricle and with the shape of small puncture/patch, part of them merged into the big patch; another kind of lesions was found scattered sparsely at frontal, parietal lobes and two sides of the periventricle, with small patches in shape. The chronic lesions had an appearance of shrinking, sharp edge, even signals, and had no lunar circle phenomena and obvious enhancement.Conclusion Brain MS have diverse MRI appearence, with some of which are unique and symbolic.

Objective To evaluate the value of dynamic susceptibility-contrast (DSC) MR perfusion imaging in differentiating benign and malignant meningiomas on the basis of differences in their vascularity in both tumor parenchyma and peritumoral region. Methods 33 patients with pre-operation meningiomas(25 benign and 8 malignant) underwent conventional and DSC MR perfusion imaging. Maximum relative cerebral blood volume (rCBV) and corresponding relative mean transit time (rMTT) values of the same part in both tumor parenchyma and peritumoral region were calculated (compared with contralateral normal white matter). The peritumoral region was defined as the area immediately adjacent (0.05) in parenchyma part and both were statistically significant (t test, ?

Objective To explore the significance and value of loss of digitations of hippocampal head in diagnosis of hippocampal sclerosis.Methods Eighteen patients with hippocampal sclerosis comfirmed by histopathological examination and 18 cases to be matched control group were examined by MRI . The digitations,atrophic change and abnormal signals of hippocampal head were evaluated retrospectively.Results Of 18 patients with hippocampal sclerosis, loss of digitations was seen in 16 cases, poorly visible in 1 case and exist in 1 case. The sclerotic hippocampal heads all had atrophic change and were hyperintensity on T_2-weighted and FLAIR MR imagings. No loss of digitations were seen in the opposite side of the hippocampal sclerosis and all hippocampal heads in control group.Conclusion The loss of digitations of hippocampal head is a sensitive indicator for the diagnosis of hippocampal sclerosis.

Objective To investigate the value of MR perfusion-weighted imaging(PWI)in the evaluation of therapeutic effect of brain metastases with gamma knife.Methods Treatment by gamma knife before and after that 3 months or 6 months PWI studies were penformed respectively in 22 patients with brain metastases .Maps of relative regional blood volume(rCBV)and mean transit time(MTT)were obtained.The ratios of rCBV and MTT of lesions were analyzed.Results rCBV of tumors in 22 cases was increased.The ratios of maximum rCBV of the lesions and opposite side were 6.16?3.12 and 1.18?0.17 respectively.The ratios of MTT of the tumors was 1.44?0.53.After gamma knife treatment,9 of 22 cases appeared decreased rCBV,but the ratios of MTT were no changing,of them,3 cases presented cerebral necrosis.13 of 22 cases,the ratios of rCBV were increased in varied degree after treatment by gamma knife,and 6 cases presented brain radionecrosis.Conclusion PWI is a significant method in evaluating the therapeutic effect of brain metastases with gamma knife