Although many investigators have visually assessed the performance of barium contrast media, there has been no objective analysis of barium contrast media adhesion. We hypothesized that spectrum analysis may be useful for the objective evaluation of adhesion, because it has been shown to be useful in medical image analysis and diagnosis in other fields. We found a relationship between the power spectrum component of X-ray images and fluctuations in the concentration of barium contrast media. Therefore, we applied the "Power Spectrum Integral Value" to evaluate adhesion. We determined the power spectrum of X-ray images with fluctuating patterns caused by barium contrast media by using a commercially available personal computer and an image scanner, and determined the adhesion curve using the power spectrum integral. Our results showed a good correlation between the adhesion curve determined by visual evaluation and the curve determined by our method. In conclusion, spectrum analysis makes it possible to evaluate the adhesion of barium contrast media quickly and objectively. We believe that it also may be useful in comparing the performance of several barium contrast media and in providing other relevant information.
A comparative time study of radiological reporting, with and without the use of RIS (radiological information system), was conducted as a series of technology assessments. The purpose was to measure the efficacy of RIS quantitatively, and to maximize it in a hospital by comparing the status of diagnostic reporting quantitatively before and after the introduction of RIS. Another target was to obtain the essential data for the improvement of RIS operations. RESULTS : 1) The average time needed to make a diagnostic report employing the RIS terminal increased by as much as 2.9 times. Further, the number of characters in a report significantly increased by 3.8 times. These results suggest that more detailed reporting (factor 3.8) is facilitated by the extended reporting time (factor 2.9). "Factor" means the ratio of numerical values such as the ratio of the number of characters after RIS operation divided by that before RIS operation, and the ratio of reporting time after RIS operation divided by that before RIS operation. However, we intend to let the word "factor" express other meanings such as the degree of detail of reports. These other meanings are described in the paper. 2) The frequency of employing anatomical sketches was increased by 2.8 times, showing one way that RIS contributes to easier radiological reporting. 3) The effectiveness of RIS in same areas of reporting has been suggested by these results of measurement.
We measured basic imaging properties like dose attenuation ratio, photostimulated emission, resolution property (presampling MTF : MTF_<PRE>) and noise property (digital Wiener spectrum : WS_<DIG>) using various versions of HR and ST imaging plates. Resolution property was almost the same for three respective versions of the HR and ST plates. The photostimulated emission of HR III_N was higher than that of III and V by about 50% and 20%, respectively. The noise property of HR V was superior to that of other plates. In terms of the photostimulated emission of ST plates, there was no difference between III and III_N, however, that of V was about 10% higher than that of other plates. The noise property of ST V was superior to that ot III_N. ST III has a different type of structure mottle than versions III_N and V.
For the visual evaluation of X-ray images, we use a sensory test, Thurstone's method of paired comparisons, in which differences between samples are detected with high sensitivity by making a Yes or No judgement. However, with this method, large differences between paired samples can't be transformed into an interval scale because the evaluation for the pair becomes missing value. In an attempt to overcome this problem, we examined Scheffe's method of paired comparisons for the subjective evaluation of X-ray images, in which the scored data are examined by analysis of variance. Scheeffe's method was concluded to be useful in overcoming the above-mentioned problem and even in analyses of variance among observations.
Quality control of CRT (cathode ray tube) monitors is essential to the good management of cineradiographic systems. In this study, we developed a new video signal generator and measured the output luminance of 35 systems in our five institutes. The results were as follows : 1. Our video signal generator (VG-812) may be useful in quantitatively analyzing the luminance of CRT monitors. 2. There were large differences in luminance among CRT monitors in the clinical setting. The gradient of the video signal-luminance curve ranged between 1.38 and 2.91. The coefficient of variation ranged from 8% to 22%. 3. The life of CRT monitors may be indicated by periodically measuring the declline curve of luminance under the usual setting and the maximum contrast value, using the video signal generator.