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Kun-cheng Li

Publications and source records attributed to Kun-cheng Li.

7 recordsLinked to original sources
PubMed2006

Diffusion tensor imaging in medial temporal lobe epilepsy.

BACKGROUND: Diffusion tensor imaging (DTI) is a noninvasive imaging technique for the assessment of the integrity of cerebral tissues. This study was undertaken to assess the changes of diffusion indices of hippocampal formation (HF) in patients with medial temporal lobe epilepsy (MTLE). METHODS: Fourteen patients with MTLE and 14 healthy subjects were evaluated. Mean diffusivity (MD) and fractional anisotropy (FA) from the symmetrical-voxel sampling regions of the anterior HF were calculated in all subjects. The MD and FA values were compared across the groups. RESULTS: No significant differences of MD and FA values were noted between right and left HF in the controls. In the patient group, MD significantly increased in the HF ipsilateral to the lesioned side [(9.27 +/- 1.09) x 10(-4) mm(2)/s], compared with the values in the contralateral HF [(8.20 +/- 0.59) x 10(-4) mm(2)/s] (t = 4.479, P = 0.001) and healthy subjects [(7.58 +/- 0.51) x 10(-4) mm(2)/s] (P < 0.001), but no significant differences were found in FA. When compared with the controls, patients had a significantly higher MD in the contralateral HF (P < 0.05), but the difference in FA was not statistically significant. CONCLUSIONS: DTI could detect hippocampal abnormality in patients with MTLE. This technique may be helpful for preoperative evaluation of such patients.

Adolescent↗
PubMed2006

[Diffusion tensor imaging of the normal-appearing brain tissue in relapsing-remitting multiple sclerosis].

OBJECTIVE: To investigate whether normal-appearing brain tissue (NABT) on conventional MRI has occult damage in patients with relapsing-remitting multiple sclerosis (RRMS) by using diffusion tensor imaging (DTI) histogram analysis, and to determine the correlations between DTI histogram-derived measures of the NABT and expanded disability status scale (EDSS) scores, disease durations, T2WI lesion volumes and brain tissue volumes in RRMS patients. METHODS: Conventional MRI and DTI scans were performed in 24 patients with RRMS and 24 sex- and age-matched healthy controls. After segmentation of the NABT, the mean diffusivity (MD) and fractional anisotropy (FA) histograms of the NABT were created and analyzed. RESULTS: In patients with RRMS, the average MD (1.014 x 10(-3) mm2 x s(-1)) of the NABT was higher than that (0.910 x 10(-3) mm2 x s(-1)) of control subjects (t = 7.238, P < 0.001); the MD histogram peak height (8.858 per thousand) of the NABT was lower than that (0.767 per thousand) of control subjects (t = 6.161, P < 0.001); the MD histogram peak location (0.809 x 10(-3) mm2 x s(-1)) of the NABT was higher than that (0.767 x 10(-3) mm2 x s(-1)) of control subjects (t = 5.324, P < 0.001); the average FA (0.231) of the NABT was lower than that (0.254) of control subjects (t = 6.217, P < 0.001); the FA histogram peak height (4.502 per thousand) of the NABT was higher than that (4.107 per thousand) of control subjects (t = 4.198, P < 0.001); no significant difference was found in the FA histogram peak location of the NABT between these two groups (t = 1.223, P = 0.227); none of the DTI histogram-derived measures correlated with EDSS scores or disease durations (P > 0.05); the average MD and all the FA histogram-derived measures correlated with T2WI lesion volumes (P < 0.05); and the average MD, the MD histogram peak height and all the FA histogram-derived measures correlated with brain tissue volumes (P < 0.05). In healthy controls, however, only the average FA of the NABT correlated with brain tissue volumes. CONCLUSION: Patients with RRMS had occult damage in the NABT and the extent of NABT damage was related to the lesion load of brain and to the extent of brain tissue atrophy.

Adolescent↗
PubMed2005

Primary study on imaging in transient ischemic attacks.

BACKGROUND: Although transient ischemic attacks (TIA) is a clinical diagnosis, imaging findings are important for its diagnosis and treatment. This study evaluated the value and limitations of conventional CT, CT cerebral perfusion imaging and transcranial Doppler sonography (TCD) in patients with TIA. METHODS: Conventional CT, CT cerebral perfusion imaging and TCD were performed in 20 patients with TIA. After regular CT examination, 40-second dynamic scans were performed on selected slice, while 40 ml of non-ionic contrast materials was bolus-injected through antecubital vein with power injector. These dynamic images were processed with the perfusion software package on workstation. Cerebral blood flow (CBF) and time to peak (TTP) were measured in specific regions of the brain. TCD was also performed in 20 patients with TIA. Comparative analysis was made on the basis of the results of conventional CT, CT cerebral perfusion imaging and TCD. RESULTS: In the 20 patients with TIA, conventional CT turned out to be normal. However, persisting abnormal perfusion changes corresponding to clinical symptoms were found in 13 cases with the prolonged TTP. The other 7 cases were normal. TTP of the affected side (11.6 +/- 3.0) s was significantly prolonged (t = 4.782, P < 0.01) in comparison with the contralateral side (8.8 +/- 1.5) s. The difference in CBF was not statistically significant (t = 1.912, P = 0.073) between the affected side [(223.9 +/- 19.6) ml.min(-1).L(-1)] and the contralateral side [(227.7 +/- 19.8) ml.min(-1).L(-1)]. TCD revealed severe stenosis or occlusion of the carotid artery in 10 patients, arteriosclerosis in 6 patients, blood speed decrease in 2 patients, vasospasm in 1 patient. CONCLUSIONS: Conventional CT can exclude intracerebral diseases. Perfusion CT provides valuable hemodynamic information and shows the extent of perfusion disturbances. TCD can demonstrate abnormalities of the involved arteries in patients with TIA. The combination of these three imaging methods can provide more diagnostic information.

Adult↗
PubMed2005

[Visual search in Alzheimer disease--an functional magnetic resonance imaging study].

OBJECTIVE: To investigate the functional activation patterns during two types of visual search tasks in Alzheimer's disease (AD) with functional MRI, and probe the neuro-anatomic basis of visual attention. METHODS: 13 patients with AD and 13 sex and age-matched healthy subjects participated in the experiment designed with two visual search tasks. The first was a "pop-out" single feature task, detecting a vertical target among horizontal distractors, and the second was a conjunction task where the target was defined by conjunction of feature (color and orientation) and the performance depended on some shifting of attention. The fMRI data were collected by Siemens 1.5 T Sonata magnetic resonance imaging (MRI) system and analyzed by Statistical Parametric Mapping software (SPM 99) to generate the activation map. RESULTS: AD patients had a particular impairment in the conjunction task but not in the single-feature task. Although both groups revealed overlapping networks engaged in the conjunction tasks including the superior parietal lobule (SPL), frontal and occipitotemporal cortical regions (OTC), primary visual cortex and some subcortical structures, the most pronounced difference between them was found in bilateral SPL (more activities in the controls) and right OTC (more activities in the patients). The difference between the 2 groups was small in the pop-out condition. CONCLUSION: AD particularly affects those mechanisms controlling spatial shifts of attention. Some additional remote activation (ventral visual stream and temporal lobe) can be interpreted as dynamic reallocating of brain functional resource.

Aged↗
PubMed2005

Application of functional MRI in epilepsy.

OBJECTIVE: To review the recent development of functional MRI application in epilepsy. DATA SOURCES: Both Chinese and English language literatures were researched using MEDLINE/CD ROM (1996 - 2005) and the Chinese Biomedical Literature Disk (1996 - 2005). STUDY SELECTION: Published articles about functional MRI application and epilepsy were selected. DATA EXTRACTION: Data were mainly extracted from 38 articles which are listed in the reference section of this review. RESULTS: fMRI can be used to localize seizure foci through detecting these cerebral hemodynamic changes produced by epileptiform discharges. EEG-triggered fMRI, which has higher spatial and temporal resolution, helps to detect the spatiotemporal pattern of spike origin and propagation, and define localization of the epileptogenic focus. fMRI is also useful in language and memory cognitive function assessment and presurgical assessment of refractory epilepsy. Atypically distributed cognitive function areas can be detected by fMRI, because of cortical language and memory areas reorganization during long-term epileptic activity in patients with epilepsy. CONCLUSIONS: fMRI technique plays a very important role in cognitive function and presurgical assessment of patients with epilepsy. It is meaningful for understanding pathogenesis of epilepsy.

Cognition↗
PubMed2003

[MRI-guided stereotactic biopsy for questionable diseases in brain].

OBJECTIVE: To explore the accuracy and role of magnetic resonance imagine (MRI)-guided stereotactic biopsy for atypical diseases in brain. METHODS: Using MRI volume scan and multiplane reconstruction, MRI-guided stereotactic brain biopsies were performed with CRW stereotactia frame in twenty-six patients whose lesions were atypical or unable to be detected by CT scanning. RESULTS: No serious complication (intracranial hematoma, paralysis) caused by brain biopsy was found in all twenty-six patients. Definite pathologic diagnosis and appropriate treatment were given to these patients. The lesions included gliomatosis cerebri, brain cysticercosis and Krabbe's disease, et al. CONCLUSIONS: MRI-guided stereotactic brain biopsy is more accurate for pathological diagnosis than CT-guided stereotactic brain biopsy. MRI-guided stereotactic biopsy can provide reliable diagnosis and treatment especially for the questionable lesions in brain.

Adolescent↗