Abstract: OBJECTIVE: The aim of this study was to compare the computed tomographic colonography (CTC) image quality and patient acceptance of three iodine-based faecal tagging bowel preparations in 60 patients undergoing the following regimens: a 2-day regimen of meal-time administration of iodine and phospho-soda (GFPH); a 2-day regimen of meal-time mild laxative, followed by iodine administered 2 h before CTC (SD); and a 2-day regimen of meal-time administration of iodine (GF). METHODS: Two independent radiologists assessed tagging quality; quantitative measures included the tagged stool density, and computer-aided detection (CAD) false-positive rate. RESULTS: The GFPH and SD regimens provided better subjective quality than GF (p < 0.001). The latter regimen resulted in a higher proportion of insufficiently tagged segments: the measured average stool density was less than 200 HU in 10.7% in all segments vs 3.6% for SD and <0.5% for GFPH, respectively. Insufficient tagging occurred mostly in the ascending colon and the caecum. The CAD false-positive rate increased following the trend: GFPH < SD < GF (p = 0.00012). GFPH was worse tolerated than SD (p < 0.05). CONCLUSIONS: Considering preparation quality alone, GFPH was the best regimen, but SD provided the best balance between bowel preparation quality and patient acceptability.
Abstract: Regional differences in tissue volume and perfusion in brains of individuals with mild cognitive impairment (MCI) versus normal healthy age-matched controls (NC), and the differences between MCI-AD converters and stable MCI patients were investigated. MRI and SPECT scans were performed on 13 MCI (74+6 years) and 12 NC (75+4 years). Of the MCI patients, 10 were followed for up to three years and 4 subsequently converted to Alzheimer's disease (AD). Episodic memory function was assessed using tests of delayed recall for word lists and stories. The volume reductions and hypoperfusion were mainly confined to the medial temporal lobe (MTL) of MCI patients and associated with worse scores on memory tests. Perfusion in the corpus callosum and the gray matter of frontal, lateral temporal, parietal or occipital lobe was not significantly affected in MCI. The 4 MCI-AD converters had relatively low MTL structural volume and perfusion compared to their stable peers.
Abstract: An automatic method for the segmentation of the colonic wall is proposed for abdominal computed tomography (CT) of the cleansed and air-inflated colon. This multistage approach uses an adaptive 3D region-growing algorithm, with a self-adjusting growing condition depending on local variations of the intensity at the air-tissue boundary. The method was evaluated using retrospectively collected CT scans based on visual segmentation of the colon by expert radiologists. This evaluation showed that the procedure identifies 97% of the colon segments, representing 99.8% of the colon surface, and accurately replicates the anatomical profile of the colonic wall. The parameter settings and performance of the method are relatively independent of the scanner and acquisition conditions. The method is intended for application to the computer-aided detection of polyps in CT colonography.
Abstract: DCE-MRI is a diagnostic method that can visualize neoangiogenic-induced vascular changes. Typically, the analysis of these data is time-consuming and the visualization of the quantitative information on tumor vasculature, derivable from DCE-MRI, is not easy and comfortable. In this study, we propose a method to accelerate computation and analysis of DCE-MRI data, while making easy to use the functional information obtained from model-based functional analysis.
Abstract: PURPOSE: To prospectively evaluate regional alterations in the apparent diffusion coefficient (ADC) of cortical gray and white matter and subcortical structures that are known to be involved in mild cognitive impairment (MCI). MATERIALS AND METHODS: Magnetic resonance (MR) imaging was performed in 13 patients with MCI (nine men, four women; mean age, 74 years +/- 6 [standard deviation]) and 13 healthy elderly control subjects (seven men, six women; mean age, 75 years +/- 4). This study was approved by the institutional review board and was HIPAA compliant. Each subject gave informed consent. ADC was measured from manually drawn regions of interest (ROIs) of the hippocampus, parahippocampal gyrus, amygdala, corpus callosum, and anterior and posterior cingulate gyrus and from automatically defined frontal, parietal, occipital, and temporal lobes by using template masking. ROIs were outlined on anatomic images then mapped onto ADC maps by using coregistration transformation matrix. A skeleton-based region competition segmentation algorithm was used for segmentation of gray and white matter. The group difference in ADC values was assessed with independent-sample t tests. Pearson correlation analysis was used to examine the correlation of ADC values with age and memory test scores. RESULTS: Higher ADCs were found in hippocampus, temporal lobe gray matter, and corpus callosum of patients with MCI compared with that of control subjects (P < .05). By pooling all subjects together, an elevated hippocampal ADC was significantly correlated with worse memory performance scores in 5-minute and 30-minute delayed word-list recall tasks (P < .05). CONCLUSION: ADCs from gray and white matter of different brain regions can be analyzed by applying an automated template-masking method in conjunction with a skeleton-based region competition segmentation algorithm.
Abstract: The crystalline orbitals of six semiconductors (Si, C, BP, AlP, SiC and BN) are localized according to
a Wannier–Boys mixed scheme recently implemented. The degree of localization, size and shape of the localized
crystalline orbitals are documented by means of various indices (centroid position, second order central
moment tensor, its eigenvalues and principal axes, Mulliken population analysis and atomic localization
indices) and through their graphical representations. Systematic trends along the series are observed, and are
correlated to the Pauling electronegativity scale and the calculated band gap.
Abstract: The crystalline orbitals of seven oxygen containing compounds with increasing degree of covalent
character Í‘MgO, MnO, ZnO, Al2 O3 , SiO2 , AlPO4 , and CaSO4 ) are localized according to a
Wannier–Boys mixed scheme recently implemented. The resulting Wannier functions are analyzed
in terms of various indices Í‘centroids positions, second-order central moment tensor, its eigenvalues
and principal axes, Mulliken population analysis, and atomic localization indicesÍ’. Systematic trends
are observed along the series.
