Slice Shape Research Articles

3-D Anthropometric Information for Designing the Wearable

Anthropometry deals with the measurement of the dimensions and certain other physical characteristics of the body such as volumes, centers of gravity, internal properties, and masses of body segments. In addition to these measurement, 3-dimensional anthropometric informations such as body shape, body contour, body slice shape and body silhouette are very essential for designing and fitting the wearables. Our main gold in this paper is to demonstrate the use of 3-D information in connection with human sensibility thanks to several examples of body shape analysis methods, and their results. As a supplementary set of information, our desire was also to provide the reader with an international size chart.

Analysis of right ventricular areas to assess the severity of ascites syndrome in broiler chickens

Ascites syndrome in broiler chickens is defined as a condition associated with pulmonary hypertension leading to right heart failure, increased central venous pressure, passive congestion of the liver, and accumulations of serous fluids in body cavities. The syndrome is currently seen in fast-growing broiler chickens associated with an increase in the weight, volume, and area of the right ventricle of the heart. The ratio of the right ventricle weight to the total heart mass has been used to assess the consequences of increased blood pressure. The right ventricle area (RVA) can be quantified using image analysis technology. Hearts were removed from 719 male broilers at slaughter (42 d). All birds were visually scored for the incidence of ascites. A score of 0 or 1 represented slight hydropericardium, slight right heart hypertrophy, and slight edema. A score of 4 was assigned to birds with marked accumulation of ascitic fluid in one or more ceolomic cavities, pronounced dilation of the right heart, and prominent liver lesions. A cross-sectional image of each heart slice (a 4-mm-thick slice of the ventricles) was digitally recorded. Using image analysis software, the RVA, left ventricular area (LVA), and total heart area (HA) were determined. Because a slice of the heart was used in image analysis, the importance of maintaining the original shape was determined. Twenty hearts in five ranges of RVA size were scanned in four different positions, which have differing heart slice orientations and differing RVA shapes, for a comparison of positioning technique (placement) relating to the RVA. The shape of the heart slice for image analysis was observed not to be critical for the small RVA. For heart slices with large RVA values, it was found to be critical to analyze the heart slice in a standardized placement.

Interslice Shear Forces in Slope Stability Analyses—A New Approach—

A procedure for limit equilibrium slope analysis based on a realistic consideration of the mobilized interslice shear forces is presented in this paper. This new approach ensures that solutions are kinematically admissible and the possibility of convergence problems, often associated with numerical solutions, is minimized. The proposed approach recognizes the importance of slip surface geometry in estimating interslice shear forces whether vertical or non-vertical slices are used in a limit equilibrium analysis. Illustrative examples are presented and the results shown to be reasonable. The calculated factors of safety based on the new method compare very well with values based on recognized methods of analysis. Yet the method is more direct and enables a proper visualization of the transfer of mobilized normal and shear forces through a sloping soil mass above a potential slip surface. The method also gives consistent results with non-vertical slices even if the shape of non-vertical slices is varied.

Hairpin folding of subunit c of F1Fo ATP synthase: 1H distance measurements to nitroxide-derivatized aspartyl-61.

Subunit c from the F1Fo ATP synthase of Escherichia coli folds in a hairpinlike structure of two alpha-helices in a solution of chloroform-methanol-H2O, and thus resembles the structure predicted for the folded protein in the membrane. The relevance of the structure in solution to the native structure was demonstrated. Asp61 in the second helical arm was shown to retain its unique reactivity with dicyclohexylcarbodiimide (DCCD) in chloroform-methanol-H2O solution. Further, the protein purified from the Ile28-->Thr DCCD-resistant mutant proved to be less reactive with DCCD in solution. This suggested that the protein folded with Ile28 of the first helical arm close to Asp61 in the second helical arm. Subunit c in wild-type E. coli membranes was specifically labeled with a nitroxide analog of DCCD (NCCD), and the derivative protein was purified. DQF COSY spectra were recorded, and the distances between the paramagnetic nitroxide and resolved protons in the spectra were calculated based upon paramagnetic broadening of the 1H resonances. The paramagnetic contribution to T2 relaxation in the NCCD-labeled sample was calculated by an iterative computer-fitting method, where a control spectrum of a phenylhydrazine-reduced sample was broadened until the line shape of one-dimensional slices through each COSY cross-peak maximally mimicked the line shape of the paramagnetic sample. The distances calculated from paramagnetic broadening indicate that Ala24 and Ala25 in helix-1 lie close (ca. 12 A) to the derivatized Asp61 in helix-2. A model for the interaction of helices in the NCCD-modified protein was generated by restrained molecular mechanics and molecular dynamics using 25 distances of < 10-20 A derived from paramagnetic broadening in combination with 15 long-range nuclear Overhauser enhancement (NOE) restraints (2-5 A) for distances between helices and the 89 intrahelical NOEs that defined helical structure in the DCCD-modified protein.

323. 高速 CT 装置よるヘリカルスキャンの基礎的検討 : 第 10 報 : 加算平均処理によるスライス形状の改善について(高速連続 CT-6 スライス厚特性)

323. 高速 CT 装置よるヘリカルスキャンの基礎的検討 : 第 10 報 : 加算平均処理によるスライス形状の改善について(高速連続 CT-6 スライス厚特性)

323. 高速 CT 装置よるヘリカルスキャンの基礎的検討 : 第 10 報加算平均処理によるスライス形状の改善について(第 49 回総会学術大会一般研究発表予稿)

323. 高速 CT 装置よるヘリカルスキャンの基礎的検討 : 第 10 報加算平均処理によるスライス形状の改善について(第 49 回総会学術大会一般研究発表予稿)

99. ヘリカル CT 画像における截面形状の検討(第 48 回総会学術大会一般研究発表予稿)

99. ヘリカル CT 画像における截面形状の検討(第 48 回総会学術大会一般研究発表予稿)

96. 高速 CT 装置によるヘリカルスキャンの基礎的検討 : 第 5 報 (スライス形状の変化について)(CT-4 高速 CT 連続スキャン スライス厚評価)

96. 高速 CT 装置によるヘリカルスキャンの基礎的検討 : 第 5 報 (スライス形状の変化について)(CT-4 高速 CT 連続スキャン スライス厚評価)

96. 高速 CT 装置よるヘリカルスキャンの基礎的検討 : 第 5 報 (スライス形状の変化について)(第 48 回総会学術大会一般研究発表予稿)

96. 高速 CT 装置よるヘリカルスキャンの基礎的検討 : 第 5 報 (スライス形状の変化について)(第 48 回総会学術大会一般研究発表予稿)

Recognition of single 3D curved objects using 2D cross-sectional slice shapes

In this paper a new approach to recognition of single 3D curved objects is proposed. Horizontal cross-sectional slice shapes are used for 3D object representation. 3D object recognition is accomplished by matching the cross-sectional slice shapes of an input object with those of each object model. Thus, 2D image analysis techniques can be used for slice shape matching, including the use of the distance-weighted correlation for shape similarity measurement and the construction of a decision tree for decision-making. Instead of computing all the slice shapes for each input object in the recognition process, only those involved in the decision tree are computed by a data acquisition system. This increases recognition speed. Experimental results with a high recognition rate prove the feasibility of the proposed approach.

Problems with achieving saturation using methods based on bursts of rf pulses with spoilers in magnetic resonance imaging.

Attempts at saturation by nonselective rf pulses, followed by gradient spoiler pulses, are sometimes used as the basis of a method of measuring T1 in magnetic resonance imaging, because a method of this type is perceived as being less affected by slice shape artifact than partial saturation methods. This note suggests that, unless care is taken, this assumption can be quite erroneous.

The design of a multiple inversion recovery sequence for T1 measurement.

Inversion recovery has the potential to be a powerful method of determining the values of T1 in in vivo studies. However, because of its relative slowness it is not practical to undertake several experiments with different values of the interval between the magnetization inverting 180 degree pulse and the interrogating 90 degree one. The multiple inversion recovery method described here uses a series of sampling pulses, most much less than 90 degrees, to produce a series of images. It is shown that slice shape is relatively reproducible from one sample to another and that, largely as a result, the accuracy of the sequence in measuring T1 is encouraging.

Slice profile effects and their calibration and correction in quantitative NMR imaging

The signal values extracted from an NMR image matrix depend upon the NMR properties of the sample material, i.e. the proton density and relaxation times T1 and T2, and also upon various instrument parameters, one such being the slice shape. It is a common approximation to assume an ideal slice profile: one that is perfectly rectangular and invariant in shape for all applications, but in practice real slice profiles are neither. In this study the effect of the slice is included in signal intensity calculations by means of a computer simulation. Comparison is made between these slice-corrected values and values calculated on the basis of an ideal slice. Four pulse sequences are examined: saturation recovery, inversion recovery, spin echo and inversion recovery followed by spin echo.

Statistical representation of word‐initial obstruents: Adult data

The utility of a statistical representation of word‐initial obstruents (Weismer et al., previous paper) was assessed for the speech of normal, young adults. Ten subjects repeated monosyllabic words, where the initial consonant was a voiced or voiceless stop or fricative, in a carrier sentence. Each place of obstruent articulation was paired with at least two vowels and each target word was repeated six times. The target words were digitized and the first four moments (mean, variance, skewness, and kurtosis) were calculated for successive 10‐ms spectral slices, beginning with the onset of the obstruent and continuing through the third cycle of the vowel. Moments were calculated from linear and bark transformed spectra. Three of the moments (mean, skewness, and kurtosis) provide a good description of the shape and center of the spectral slices. These moments were plotted in three‐dimensional space to determine whether a unique, three‐dimensional pattern could be defined for each place of articulation. Discussion will center on the use of these moments, as they define a three‐dimensional space, to quantify acoustic events associated with obstruent production. [Work supported by NIH Awards NS13274 and NS20976.]

Errors in T2 estimation using multislice multiple-echo imaging.

Accurate T2 images calculated from multiple-echo sequences are difficult to obtain over a number of contiguous slices due to the presence of unwanted echoes that are generated at the slice edges. This problem is similar to problems encountered in single-slice imaging in the presence of rf pulse imperfections. In this paper, we use computer simulations to show that all unwanted echoes can be eliminated by defocusing them using additions to the slice-selection gradients. Accurate T2 images may then be calculated from the remaining echoes. We also present a method of experimentally displaying the slice shapes of unwanted echoes generated by a multislice imaging sequence.

Investigation of slice characteristics in nuclear magnetic resonance imaging

The quality of images and the accuracy of extracted relaxation time (T1 and T2) values in nuclear magnetic resonance (NMR) imaging is dependent on the characteristics of the slice. It is therefore important that the slice profile can be measured and to know how it behaves under different experimental conditions. Slice shape is determined in conventional selective excitation systems by the spectrum of the radiofrequency pulse used and the nature of the magnetic field gradient which is applied simultaneously. The effectiveness of the selection is also influenced by the subsequent rephasing gradient. Various methods have been used to investigate the slice shape in a practical situation using a 0.1 T resistive magnet NMR scanner and comparisons drawn with the predictions of theory.

Variations in slice shape and absorption as artifacts in the determination of tissue parameters in NMR imaging.

Existing models for the contrast between one tissue and another in NMR imaging have shown that there are regions of ambiguity particularly in spin-echo sequences. This paper indicates that there are further problems due to variations in slice formation with tissue parameters, and that it is necessary to be very conservative in assessing the magnitude of T1 in any imaging system. The change in shape affects the appearance of images due, in essence, to adjustments in partial volume effects, with some of the contributions to the signal from lesions with long T1 coming from different regions to those for normal tissue. A simple model for a slice is used because the actual form in a real imaging situation is the result of a number of factors which are usually not accurately enough known.

A multiple-pulse sequence for improved selective excitation in magnetic resonance imaging.

A new framework for selective excitation that offers simpler design and better performance than conventional excitation methods is introduced. The guidelines for choosing the appropriate radiofrequency (rf) pulse envelope in a conventional selective excitation sequence often rely on Fourier analysis, leading to less than desirable results. Although providing useful insight, Fourier analysis of the rf pulse envelope determines the resultant slice shape accurately only for small flip-angle excitations, and not for larger flip-angle excitations owing to the generally nonlinear behavior of the spin system. In the new excitation framework, additional excitation pulses (typically one) are applied in sequence with the conventional pulse to improve the performance (in phase characteristics and slice definition) over that achieved by the conventional pulse alone. Given a desired spatial spin distribution and an associated rf pulse (e.g., Fourier transform pairs), the Bloch equation is solved backwards to yield the starting distribution required for the conventional pulse to give exactly the desired output. If this residual distribution is a small flip angle away from the actual starting distribution, then Fourier analysis of the residual distribution leads to the necessary "setup" pulse. A gradient of opposite polarity during the setup obviates a refocusing interval after the setup pulse. Computer simulations have verified the efficacy of the multiple-pulse excitation sequence for both 90 degrees and 180 degrees excitations.

Use of a vapor pressure osmometer to measure brain osmolality

A method is described for determining brain osmolality with a vapor pressure osmometer. This instrument measures dew point temperature depression of a solution in vapor equilibrium in a closed chamber. The principles of vapor pressure osmolality measurement suggest that it may have some advantages over freezing point depression methodology for analysis of tissue samples. Standard solutions (sodium chloride, 290 mOsm/kg water) of 10–20 μl and at temperatures considerably lower than ambient temperature may be delivered to the osmometer and measured without effects on recorded osmolality. Quick-frozen tissue specimens that were dissected while frozen into the shape of a thin slice (0.5–1.0 mm in thickness, 4–5 mm in diameter) and delivered to the machine while still in the frozen state resulted in osmolality values with high reproducibility. With this method, the osmolality of the cerebral hemispheres of pentobarbital anesthetized rats is 305.86 ± 0.74 mOsm/kg water, a value that is significantly higher than plasma values from the same animals (297.6 ± 0.72 mOsm/kg water). The findings of this study suggest that with the use of a vapor pressure osmometer, small samples of brain tissue can be measured for osmolality with speed and high reproducibility and without the need for dilutions, weighings, calculations, and external determinations of tissue water content.