R.H. Wu

Probable Hospital Cluster of H7N9 Influenza Infection

This report shows evidence for nosocomial transmission of H7N9 influenza from a patient to two physicians who provided care.

The brain mapping on reinforcement acupuncture stimulation at ST36 (zusanli) evidenced by fMRI

To characterize the brain mapping on reinforcement acupuncture stimulation at ST36 (zusanli), and to discuss the mechanisms of acupuncture to treat diseases. fMRI was performed on 26 healthy Chinese student volunteers. Sixteen subjects were acupunctured at the acupoint ST36, while 10 others at sham-acupoint (lateral from ST36 about 3 cm). The fMRI studies were performed using a gradient echo-EPI sequence. Brain mapping were generated using GE Functool program. Cerebral blood flow and correlation coefficient (CC) of ROl were analyzed. Stimulation at the right ST36 elicited 13 brain functional areas, and 10 of these areas were the same with the sham-acupoint group. However, only the temporal gyrus was specificity while by using reinforcement manual acupuncture (MA) at ST36 (Fishers Exact test, P=0.022), and the contralateral hemisphere activation was prominent (McNemer test, P=0.020). Our results support the theory of acupuncture about meridian distribution overlapping on the whole body. The special transmission channel of meridian may exists, and it may be consist of spinal nerve and autonomic nerve. However, our results may oppose the theory concerning on stomach meridian walking lateral

Coma Duration Prediction in Diffuse Axonal Injury: Analyses of Apparent Diffusion Coefficient and Clinical Prognostic Factors

The purpose of this paper is to evaluate the hypothesis that the Apparent Diffusion Coefficient (ADC) values combined with initial clinical factors indicates the depth of shearing lesions in the brain structure and therefore relates to coma duration of diffuse axonal injury (DAI). Seventy-four adult patients (48 male and 26 female patients) with diffuse axonal injury were examined with convention MR imaging and diffusion weighted MR imaging between 2 hours and 20 days after injury. Apparent diffusion coefficient (ADC) maps were obtained and the mean ADC values of each Region of Interest (ROI) were measured using MRI console software. The lesions involvement of brainstem, deep gray matter, and corpus callosum were determined for each sequence separately as well as for the combination of all sequences. The correlations between magnetic resonance (MR) imaging findings of presence of apparent brain injury combined with initial clinical factors were investigated. Clinical characteristics, such as initial score on the Glasgow Coma Scale (GCS), age, and the number of all lesions, ADC scores of the patient in MR findings were predictive of the duration of coma. Post-traumatic coma duration of DAI could be predicted by cerebral MRI findings in the acute to subacute stage after head injury combined with clinical prognostic factors. Age, ADC scores, GCS, number of lesions are highly significant in predicting coma duration. The technique presented herein might provide a tool for in vivo detection of DAI for the coma duration at the early stages in patients with traumatic brain injury

Quantification of brain creatine concentration using PRESS sequence and LCModel: comparison with HPLC method.

To investigate the accuracy for quantification of brain total creatine (Cr) concentration using in vivo long echo time (TE) PRESS sequence with an external standard and LCModel. Ten swine and an external standard containing a detectable compounds of known concentration were studied by using 1.5 T GE Signa scanner and the standard head coil; the single-voxel proton magnetic resonance spectroscopy (1H-MRS) data was acquired from the 20-mm cubic VOI which was placed in the swine brain and external standard respectively by using the PRESS sequence with TE=135 msec, TR=1500 msec, and 128 scan averages. The quantification of Cr was accomplished by the linear combination of model spectra (LCModel). After MRS examination, each animal was sacrificed, and in vitro Cr concentration was analyzed by high performance liquid chromatography (HPLC). In the MRS group, the mean concentration of Cr was 9.37plusmn0.137mmol/kg; in the HPLC group, the mean concentration of Cr was 8.905plusmn0.126 mmol/kg. There were no statistically significant differences between two methods (P=0.491), which indicated that long TE PRESS sequence with an external standard can accurately detect the brain Cr concentration. The application of LCModel introduces more convenience for the MRS quantification

Functional Magnetic Resonance Mapping of Motor Cortex In Patients With Mass Lesions Near Primary Motor and Sensory Cortices

The purpose is to study motor cortex mapping in patients with mass lesions near primary motor and sensory cortices with BOLD-fMRI. 18 patients with mass lesions near primary motor and sensory cortices, and 8 healthy volunteers were investigated with fMRI using a 1.5 T GE Signa scanner. The specific task was repetitive selfpaced index finger to thumb opposition with a frequency of approximately 2 Hz. Each task paradigm consisted of twelve 20-second blocks alternating between rest and activation. All functional data was sent to SUN GE Advanced Workstation 4.0 for post processing. 14 patients showed functional activation near mass lesion, 4 patients failed to show, and one patient with meningeoma was excluded because of heavy head movement. Of 14 patients, the functional activation of eloquent cortex was different between the group with declination of muscle force and the group with normal muscle force, generally the activated areas of the former were more scattered, dislocated, relative smaller than that of the latter. It is concluded that fMRI is a valuable method for pre-operative evaluation of neurosurgical patients and probably can evaluate the muscle force pre- and post-operation approximately

Evolution of blood-brain barrier damage associated with changes in brain metabolites following acute ischemia.

Stroke is a serious medical condition that requires emergency care. In the case of ischemic stroke, ischemia may lead to damage to the blood–brain barrier (BBB); the damage in turn may exacerbate the condition. Therefore, noninvasive detection of BBB damage represents a challenge for experimental and clinical researchers. In this study, we assessed the onset of BBB disruption by means of T1-weighted images with administration of the contrast enhancement agent gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) and related BBB breakdown to brain metabolite changes in proton magnetic resonance spectrum (1H-MRS) in the infarcted site following middle cerebral artery occlusion (MCAO) in rats. It was shown that MCAO for 30 min and 1.5 h caused no Gd-DTPA signal change in the T1-weighted images, whereas MCAO for 1 h significantly altered some of 1H-MRS brain metabolites, suggesting that brain metabolite changes occurred earlier than BBB damage after ischemic stroke. MCAO for 2 h caused BBB breakdown, which was related to changes in the levels of some brain metabolites detected by 1H-MRS. Between the second and the third hour after MCAO, brain metabolite changes continued as the result of BBB breakdown and the concurrent overperfusion to the infarcted site, which may ameliorate the metabolite changes, thus compensating for the functional failures of the brain after stroke.

Quantification of Metabolites in Swine Brain by ^1H MR Spectroscopy Using LCModel and QUEST: A Comparison Study

Magnetic Resonance Spectroscopy (MRS) is a non-invasive technique in which biochemical information can be obtained in vivo. LCModel and QUEST are two quantization tools for magnetic resonance spectroscopy. In this paper, a comparison between LCModel and QUEST is presented. After a description of the methods, we compared their performance on quantification of dominant metabolites in the brains of a health swine and a hypoxic ischemic one. In order to acquire the absolute concentration, external reference method and water reference were used. Both tools can fit a smooth curve and a baseline. With water reference in LCModel, absolute concentrations of NAA, Cr, and Cho can be obtained accurately and the concentration of Lac can also be measured. The metabolite concentrations using external reference were compared with the two kinds of software. Both LCModel and QUEST are valuable tools in quantification of absolute concentration in vivo.

Improving spatial signal homogeneity in MR 2D chemical shift imaging using outer volume saturation bands

Many endeavors of improving chemical shift imaging (CSI) techniques have been made during last two decades. Good examples of two-dimensional CSI and three-dimensional CSI can be found in the literature. However, clinical CSI using available sequences is still not satisfactory. The purpose of this study was to assess the effect of outer volume saturation bands on signal homogeneity in MR 2D chemical shift imaging. The 2D CSI scans were acquired using a point resolved spectroscopy (PRESS) CSI sequence on a phantom filled with brain metabolites. A single PRESS volume of interest was prescribed graphically. The acquisition matrix was 18/spl times/18 phase encodings over a 24-cm FOV. Identical acquisitions were obtained with and without outer-volume saturation bands. After initial acquisition was obtained, four more acquisitions were repeated for both studies with and without saturation bands. Identical five groups of voxels were compared for both studies. Standard deviations of metabolite ratios were calculated in each group for both studies. Spectra obtained without outer-volume saturation bands showed signal to noise gradient with higher concentration of signal within voxels at the center of the volume of interest. Outer volume saturation bands reduced this gradient. In general, standard deviations of metabolite ratios with saturation bands were smaller than those without saturation bands. Improved spatial homogeneity of spectra in voxels of CSI with saturation bands was obtained. Outer-volume saturation bands improve spatial signal homogeneity of chemical shift imaging.

Evaluation of chemical shift imaging using a two-dimensional PRESSCS1 sequence: work in progress

Chemical shift imaging has not been widely used for clinical studies due to technical difficulties and current imaging quality. The purpose of this study was to find solutions to improve quality of chemical shift imaging. Both phantom and patient studies were carried out in this study. Eleven clinical patients were scanned with 2-dimensional chemical shift imaging (2D CSI) sequence. The study was performed on two 1.5-T GE Signa scanners. The 2D CSI scans were acquired using a point resolved spectroscopy (PRESS) CSI sequence. The acquisition matrix was 18/spl times/18 phase encodings over a 24-cm FOV. The slice thickness was 10 mm. TR was 1000 msec and TE was 144 msec. One excitation was acquired which gave an acquisition time of 5:28. Two SCI scans were performed with outer-volume saturation bands and without outer- volume saturation bands. Spectroscopy data were processed using GE Functool software. Without outer-volume saturation bands, the maps of metabolites were in a poor quality, generally showing higher concentration of metabolite in the center of volume of interest. With outer volume saturation, 2D CSI scans were successfully performed. Improved maps of metabolites were obtained with outer-volume saturation bands in both phantom and patient studies. Compared with the scans obtained without outer-volume bands, peripheral signal loss was reduced with outer-volume saturation bands. Outer volume saturation bands can be used to reduce fat contamination, and contaminations from air, water, other substances as well. Outer-volume saturation bands improve quality of chemical shift imaging.

Magnetic Resonance Imaging of Cerebellar Liponeurocytoma A Case Report and Review of the Literature

Cerebellar liponeurocytoma is a rare benign neuroepithelial tumour. We describe the case of a 50-year-old man presenting with signs of increased intracranial pressure and cerebellar dysfunction. Magnetic resonance imaging showed a heterogeneous, well-circumscribed cerebellar mass with a predominant adipose content. Diffusion-weighted imaging showed an isointense mass with a hyperintense rim. Craniotomy demonstrated a soft grey mass with intratumoral bright patchy yellow areas. Histological and immunohistochemical findings indicated an advanced neuronal, glial and focal lipomatous differentiation with a low level of mitotic activity.