2 resultados para Peak-to-average Ratio (par)
em Bioline International
Resumo:
Background: Intussusception represents as the invagination of a part of the intestine into itself and is the most common cause of intestinal obstruction in infants and children between 6 months to 3-years-old. Objectives: The objective of this study was to determine the recurrence rate and predisposing factors of recurrent intussusception. Patients and Methods: The medical records of children aged less than 13-years-old with confirmed intussusception who underwent reduction at a tertiary academic care in northern Iran (Mazandran), from 2001 to 2013 were reviewed. Data were extracted and recurrence rate was determined. The two groups were compared by chi square, Fisher, Mann-Whitney and t-test. Diagnosed cases of intussusception consisted of 237 children. Results: Average age of the patients was 19.57 ± 19.43 months with a peak of 3 to 30 months. Male to female ratio was 1.65 and this increased by aging. Recurrence rate was 16% (38 cases). 87 (36.7%) underwent surgery. These were mainly children under one year old. In 71% (40) of episodes recurrence occurred 1 to 7 times within 6 months. The recurrence occurred in 29 (23.5%) children in whom a first reduction was achieved with barium enema (BE) and 5 (5.7%) children who had an operative reduction (P < 0.001) in the first episode. Pathological leading points (PLPs) were observed in 5 cases; 2.6% in recurrence group versus 2% in non-recurrence group (P = 0.91). Three patients had intestinal polyp, 2 patient’s lymphoma and Mackle’s diverticulum. Age (P = 0.77) and sex (P = 0.38) showed no difference between the two groups. PLPs were observed in 1.4% of children aged 3 months to 5 years. This was 13.3%, in older children (P = 0.02). Conclusions: The recurrence of intussusception was related to the method of treatment in the first episode and it was 5-fold higher in children with BE than in operative reduction. Recurrent intussusceptions were not associated with PLPs, they were more idiopathic.
Resumo:
Purpose: To evaluate and compare the performance of Ripplet Type-1 transform and directional discrete cosine transform (DDCT) and their combinations for improved representation of MRI images while preserving its fine features such as edges along the smooth curves and textures. Methods: In a novel image representation method based on fusion of Ripplet type-1 and conventional/directional DCT transforms, source images were enhanced in terms of visual quality using Ripplet and DDCT and their various combinations. The enhancement achieved was quantified on the basis of peak signal to noise ratio (PSNR), mean square error (MSE), structural content (SC), average difference (AD), maximum difference (MD), normalized cross correlation (NCC), and normalized absolute error (NAE). To determine the attributes of both transforms, these transforms were combined to represent the entire image as well. All the possible combinations were tested to present a complete study of combinations of the transforms and the contrasts were evaluated amongst all the combinations. Results: While using the direct combining method (DDCT) first and then the Ripplet method, a PSNR value of 32.3512 was obtained which is comparatively higher than the PSNR values of the other combinations. This novel designed technique gives PSNR value approximately equal to the PSNR’s of parent techniques. Along with this, it was able to preserve edge information, texture information and various other directional image features. The fusion of DDCT followed by the Ripplet reproduced the best images. Conclusion: The transformation of images using Ripplet followed by DDCT ensures a more efficient method for the representation of images with preservation of its fine details like edges and textures.