Histopathological Study of Chronic Hepatitis B: A Comparative Study of Ishak and METAVIR Scoring Systems.

BACKGROUND: Ishak and METAVIR scoring systems are among the most commonly used histopathological systems to evaluate chronic hepatitis. OBJECTIVE: To assess the level of agreement between these two scoring systems in patients with chronic hepatitis B. METHODS: Liver biopsy samples taken from 92 patients with chronic hepatitis B were considered as the training set; 57 more biopsy specimens were used as the validation set. In the training set, grade of necroinflammation and stage of fibrosis for each liver biopsy specimen were determined by two expert liver pathologists using both Ishak and METAVIR systems. Inter-observer variability between the two pathologists was evaluated. Biopsy specimens of the validation set were seen and scored by a third expert pathologist. In the training set, criteria were developed to categorize Ishak grading and staging systems separately to best fit with the METAVIR scoring system. The criteria found in the training set, was then tested in the validation set. The level of agreement between the two scoring systems was assessed by weighted kappa statistics. RESULTS: For the training set, agreement between the two pathologists was excellent. Using our proposed criteria in the training set, there was excellent level of agreement in grading (κ = 0.89) and staging (κ = 0.99) between Ishak and METAVIR systems. In the validation set, the criteria led to substantial correlation (κ = 0.61) in grading, and excellent correlation (κ = 0.94) in staging between the two systems. CONCLUSION: Using our proposed criteria, excellent or at least substantial concordance between Ishak and METAVIR scoring systems can be achieved for the degree of both necro-inflammatory changes and fibrosis.

Essential oil compositions of Cymbopogon parkeri STAPF from Iran.

Aerial parts of aromatic grass, Cymbopogon parkeri STAPF, were collected at flowering stage from Kerman province of Iran. The essential oil of air dried samples obtained by hydro-distillation method. The compositions of the essential oil were determined by the use of GC and GC-MS. Nineteen (98.7%) constituents were identified. The main constituents were piperitone (80.8%), germacrene-D (5.1%), santolinyl acetate (2.1%) and alpha-eudesmol (2.1%).

Binary nonlinear joint transform correlator performance with different thresholding methods under unknown illumination conditions.

The correlation performance of binary joint transform correlators with unknown input-image light illumination is investigated for different thresholding methods used in the Fourier plane. It is shown that a binary joint transform correlator that uses a spatial frequency dependent threshold function for binarization of the joint power spectrum is invariant to uniform input-image illumination. Computer simulations and optical experimental results are provided.

Performance of an optimum receiver designed for pattern recognition with nonoverlapping target and scene noise.

The design of an optimum receiver for pattern recognition is based on multiple-alternative hypothesis testing with unknown parameters for detecting and locating a noisy target or a noise-free target in scene noise that is spatially nonoverlapping with this target. The optimum receiver designed for a noise-free target has the interesting property of detecting, without error, a noise-free target that has unknown illumination by using operations that are independent of the scene-noise statistics. We investigate the performance of the optimum receiver designed for nonoverlapping target and scene noise in terms of rotation and scale sensitivity of the input targets and discrimination against similar objects. Because it is not possible in practical systems to have a completely noise-free target, we examine how the performance of the optimum receiver designed for a noise-free target is affected when there is some overlapping noise on the target. The application of the optimum receiver to binary character recognition is described. Computer simulation results are provided.

Performance of the nonlinear joint transform correlator for images with low-pass characteristics.

The correlation performance of the nonlinear joint transform correlator for input images containing a target embedded in input noise is investigated. We focus on a class of images for the target, the input image, and the input noise for which nonlinear joint transform correlators perform well. The target and the input noise have low-pass characteristics; that is, they are not band limited but have most of their energies in the low spatial frequency domain. The analytical results show that for this class of low-pass (but not band-limited) images, the binary joint transform correlator outperforms other types of kth-law nonlinear joint transform correlators with k ≠ 0 when the input-noise bandwidth is less than the target bandwidth. We show that binary nonlinear joint transform correlators perform well when the input noise is signallike; that is, the input noise or the objects to be rejected have energy spectra that are similar to the target energy spectrum. Correlation tests with computer simulations are prese ted. The nonlinear joint transform correlator performance is determined for various degrees of nonlinear transformations and for different input-noise parameters. For the nonlinear joint transform correlator the correlation-signal term and the output-noise term arising from the input noise are determined for various degrees of nonlinearity for the target embedded in input noise.