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Biomedical subjects

Xiangke Du

Publications and source records attributed to Xiangke Du.

8 recordsLinked to original sources
PubMed2006

Delayed hyperenhancement patterns in occlusive and reperfused myocardial infarcts during different healing stages.

PURPOSE: To investigate delayed hyperenhancement during different healing stages of myocardial infarct with and without reperfusion in a pig model. MATERIALS AND METHODS: Twelve pigs were studied. Six pigs were subjected to permanent right coronary artery (RCA) occlusion, and the other six were subjected to transient 90-minute RCA occlusion. In vivo MRI including first-pass perfusion and myocardial delayed enhancement (MDE) was performed at four, eight, 12, and 24 hours, and eight days after the artery occlusion. The MDE scan was repeated four times, two to 32 minutes after contrast administration. RESULTS: For all six pigs without reperfusion, the four-hour MRI showed transmural perfusion defect and no delayed hyperenhancement; from eight hours on, delayed hyperenhancement appeared and its spatial extent gradually increased until it became transmural hyperenhancement at eight days. However, in all six pigs with reperfusion, hyperenhancement was present at every stage from four hours to eight days. Pathology confirmed the existence of infarct at various stages of healing irrespective of reperfusion status. CONCLUSION: Occlusive hyperacute infarct did not exhibit any delayed hyperenhancement, which indicates that perfusion plays an important role in delayed enhancement at the hyperacute stage.

Animals↗
PubMed2005

Diffusion-weighted MR study of femoral head avascular necrosis in severe acute respiratory syndrome patients.

PURPOSE: To evaluate the apparent diffusion coefficient (ADC) of femoral head avascular necrosis (AVN) in severe acute respiratory syndrome (SARS). MATERIALS AND METHODS: Seventy-nine SARS patients with hip pain underwent both conventional and diffusion-weighted MRI (b-value=0-1000 seconds/mm(2)). The abnormal regions on the diffusion-weighted images were outlined by using the conventional images as guides, and the ADCs were calculated. The ADC differences between normal and AVN femoral heads were compared. RESULTS: Of the 158 hips examined, 28 had AVN (11 with bilateral hip AVN, three with right hip AVN, and three with left hip AVN). The mean ADC was markedly greater in the AVN femoral head (1.66 x 10(-3) mm(2)/second+/-0.20) than in the normal femoral head (0.47 x 10(-3) mm(2)/second+/-0.082; P<0.0001). There was no overlap between the normal and AVN femoral heads. CONCLUSION: DWI can provide valuable information regarding the diffusion properties of femoral head AVN, and markedly increased diffusion was identified in AVN.

Adult↗
PubMed2004

Anterior cingulum abnormalities in male patients with schizophrenia determined through diffusion tensor imaging.

OBJECTIVE: This study used diffusion tensor imaging to examine fractional anisotropy in the anterior cingulum and posterior cingulum bundles in patients with schizophrenia. METHOD: Twenty-one male patients and 20 healthy comparison men were studied. RESULTS: Reduced fractional anisotropy was seen for both sides of the anterior cingulum in the schizophrenia patients, who also exhibited less left-greater-than-right asymmetry in the anterior cingulum than was seen in the comparison subjects. CONCLUSIONS: The findings suggest structural disconnections in the anterior cingulum in patients with schizophrenia.

Analysis of Variance↗
PubMed2003

Abnormal anterior cingulum in patients with schizophrenia: a diffusion tensor imaging study.

Diffusion tensor imaging (DTI) can non-invasively examine the molecular diffusion of water in vivo and directly reflects the anatomical integrity of neural fibers in white matter. Fractional anisotropy (FA) can be calculated from DTI data, and utilized to evaluate white matter integrity. DTI was performed on 30 patients with schizophrenia and 19 healthy controls, and their FA values were subsequently measured in multiple brain regions. Statistical analyses revealed that FA values were decreased in the anterior cingulum of schizophrenia subjects. There were no significant differences between patients and controls in any other regions. This study supports the hypothesis that schizophrenia is associated with abnormal white matter integrity of the anterior cingulum.

Adult↗
PubMed2003

A diffusion tensor imaging study of middle and superior cerebellar peduncle in male patients with schizophrenia.

Many studies have confirmed that the cerebellum takes part in higher-order cognitive coordination; profound fibers projecting to and from the cerebellum underlie its cognitive function. Since the superior and middle cerebellar peduncles are the main pathways of neural fibers in the cerebellum, these structures became the focus of our interest in evaluating the cognitive dysfunction reported in schizophrenia. Diffusion tensor imaging (DTI) was used to examine the anatomical integrity of the neural fibers in the superior and middle cerebellar peduncles. DTI was performed on 29 patients and 20 normal controls; we subsequently calculated the fractional anisotropy and mean diffusivity in these regions. Statistical analysis revealed that there was no significant difference between patients with schizophrenia and our matched control group. No structural abnormalities were detected in the white matter of the superior and middle cerebellar peduncles.

Adult↗
PubMed2003

[The investigation of clinical images of 88 hospital staff with SARS].

OBJECTIVE: To investigate the clinical thoracic images of hospital staff with SARS. METHODS: Thoracic images was analyzed in 88 medical workers with SARS, including 394 chest plain films and 9 CT scans. RESULTS: The typical signs of SARS are multifocal air-space consolidations, and progress over a day from small shadow to becoming generalized. CONCLUSION: Thoracic plain film was necessary for diagnosis of SARS, CT could detect the pulmonary abnormality of SARS early.

Adult↗
PubMed2003

Four-winged dinosaurs from China.

Although the dinosaurian hypothesis of bird origins is widely accepted, debate remains about how the ancestor of birds first learned to fly. Here we provide new evidence suggesting that basal dromaeosaurid dinosaurs were four-winged animals and probably could glide, representing an intermediate stage towards the active, flapping-flight stage. The new discovery conforms to the predictions of early hypotheses that proavians passed through a tetrapteryx stage.

Animals↗