Diagnosis of Takayasu arteritis is difficult because the clinical features are similar to those of other diseases. In early-phase Takayasu arteritis, computed tomography (CT) and magnetic resonance (MR) imaging show thickening of the aortic wall. Late-phase Takayasu arteritis has been classified into four types: classic pulseless disease (type I), a mixed type (type II), the atypical coarctation type (type III), and the dilated type (type IV). In late-phase Takayasu arteritis, angiography usually demonstrates luminal changes such as stenosis, occlusion, or aneurysmal dilatation of the aorta and pulmonary artery and their branches. However, absence of such luminal changes does not exclude the possibility of early-phase Takayasu arteritis. Improvement in the clinical findings and subsidence of the active inflammatory process can be expected with early steroid treatment. Familiarity with the varied chest radiographic, angiographic, CT, and MR imaging features of Takayasu arteritis will permit earlier diagnosis and treatment.
This study describes an effective method for verifying line spread function (LSF) and point spread function (PSF) measured in computed tomography (CT). The CT image of an assumed object function is known to be calculable using LSF or PSF based on a model for the spatial resolution in a linear imaging system. Therefore, the validities of LSF and PSF would be confirmed by comparing the computed images with the images obtained by scanning phantoms corresponding to the object function. Differences between computed and measured images will depend on the accuracy of the LSF and PSF used in the calculations. First, we measured LSF in our scanner, and derived the two-dimensional PSF in the scan plane from the LSE Second, we scanned the phantom including uniform cylindrical objects parallel to the long axis of a patient's body (z direction). Measured images of such a phantom were characterized according to the spatial resolution in the scan plane, and did not depend on the spatial resolution in the z direction. Third, images were calculated by two-dimensionally convolving the true object as a function of space with the PSF. As a result of comparing computed images with measured ones, good agreement was found and was demonstrated by image subtraction. As a criterion for evaluating quantitatively the overall differences of images, we defined the normalized standard deviation (SD) in the differences between computed and measured images. These normalized SDs were less than 5.0% (ranging from 1.3% to 4.8%) for three types of image reconstruction kernels and for various diameters of cylindrical objects, indicating the high accuracy of PSF and LSF that resulted in successful measurements. Further, we also obtained another LSF utilizing an inappropriate manner, and calculated the images as above. This time, the computed images did not agree with the measured ones. The normalized SDs were 6.0% or more (ranging from 6.0% to 13.8%), indicating the inaccuracy of the PSF and LSE We could verify LSFs and PSFs for three types of reconstruction kernels, and demonstrated differences between modulation transfer functions (MTFs) derived from validated LSFs and inaccurate LSFs. Our technique requires a simple phantom that is suitable for clinical scanning, and does not require a particular phantom containing some metals or specific fine structures, as required in methods previously used for measurements of spatial resolution. Therefore, the scanned image of the phantom will be reliable and of good quality, and this is used directly as a confident reference image for the verification. When one obtains LSF, PSF or MTF values, verification using our method is recommended. Further, when another method for the measurement of LSF and PSF is developed, it could be validated using our technique, as illustrated in the method proposed by Boone [Med. Phys. 28, 356-360 (2001)] and used in this paper.
IntroductionBone homeostasis is maintained through a balance between osteoblastic bone formation and osteoclastic bone resorption. Bone loss is induced due to decreased osteoblastic bone formation and increased osteoclastic bone resorption with various pathologic states. Osteoporosis with its accompanying decrease in bone mass is widely recognised as a major health problem. Nutritional and functional food factors may play a role in preventing bone loss with aging. Materials and methodsThis study was undertaken to determine the effect of marine algae Sargassum horneri extract on osteoblastogenesis and osteoclastogenesis in vitro. Results S. horneri extract enhanced bone morphogenic protein-2 or transforming growth factor-β1-induced Smad activation, measured by Sma-d4-luciferase reporter assay in osteoblastic MC3T3-E1 cells. The extract also depressed tumour necrosis factor-α-induced increase in osteoblastic nuclear factor-Marine algae Sargassum horneri bioactive factor stimulates osteoblastogenesis and suppresses kappa B-luciferase activity and receptor activator of nuclear factorkappa B-ligand-induced increase in pre-osteoclastic nuclear factorkappa B-luciferase activity. ConclusionThis study demonstrates that an extract of S. horneri does have an effect on osteoblastogenesis and ost-eoclastogenesis in vitro.
Size and density measurements of objects undertaken using computed tomography (CT) are clinically significant for diagnosis. To evaluate the accuracy of these quantifications, we simulated three-dimensional (3D) CT image blurring; this involved the calculation of the convolution of the 3D object function with the measured 3D point spread function (PSF). We initially validated the simulation technique by performing a phantom experiment. Blurred computed images showed good 3D agreement with measured images of the phantom. We used this technique to compute the 3D blurred images from the object functions, in which functions are determined to have the shape of an ideal sphere of varying diameter and assume solitary pulmonary nodules with a uniform density. The accuracy of diameter and density measurements was determined. We conclude that the proposed simulation technique enables us to estimate the image blurring precisely of any 3D structure and to analyze clinical images quantitatively.
The long-term effects of neutralized dialysate used in continuous ambulatory peritoneal dialysis (CAPD) were evaluated in 8 well-controlled patients. Twelve milliliters of 8.4% sodium bicarbonate was added to Dianeal PD-1 immediately before every administration. The final pH was 6.8 and the concentration of sodium bicarbonate was 6 mmol/l. The final sodium level was 138 mEq/l. This dialysate was used for 5 months. For 2 months before and 3 months after this period, Dianeal PD-2 was used as the dialysate for comparison. Blood bicarbonate levels significantly improved during the use of the neutralized dialysate. Blood sodium, chloride and magnesium levels and the effluent volume significantly increased. Sodium balance improved during the period when neutralized dialysate was used. Total leukocyte counts in the effluent decreased, and leukocyte viability increased. Abdominal distention, abdominal pain during instillation, nausea and headache improved. No side effects, including peritonitis, occurred during the trial of neutralized dialysate. The results suggest that this dialysate was less irritating to the peritoneal membrane than the control dialysate and that the therapeutic effects were satisfactory.
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