To evaluate the clinical usefulness of the Ultra-Vision (U-V) system, its fundamental imaging properties were compared with those of conventional blue (BH III/RX) and green (HR4/HRS, HR8/HRS) screen-film systems. The basic imaging properties were evaluated by measuring characteristic curves, relative speeds, resolution properties (square wave response functions), and noise WS (Wiener spectra). The clarity of details of various parts of clinical radiographs obtained with the U-V and conventional blue (BH III/RX) systems were compared subjectively. Six board-certified radiologists and 7 radiological technicians independently reviewed the radiographic contrast, resolution, noise, and overall image quality of the two examinations. The resolution of the U-V system was signifcantly better than that of the conventional system, however, noise was greater with the U-V system. The overall image quality of bone radiographs obtained with the U-V system was superior to that of radiographs obtained with a conventional HR4/HRS system. However, cases of inferior quality were found in chorecystography and pyelography because of the increased noise of the U-V system. It was concluded that the new U-V system is useful for radiographs that require high resolution, e. g. bone radiographs, but noise needs to be decreased for radiographs of other regions.
A study was done to investigate signal elimination of the digestive tract on T_2 weighted MR images by the combined use of a positive oral contrast medium (ferric ammonium citrate, FerriSeltz) and fast inversion recovery (fast IR pulse sequences). The experimental results revealed signal suppression on fast IR (TI 150 and 200ms) at the ordinary concentration of FerriSeltz (100mg Fe/300ml=5.97mmol/l). It was not necessary to use a concentration as high as that on fast SE, probably because the null point of FerriSeltz aqueous solution (5.97mmol/l) is around 150-200ms. Because no negative oral contrast medium for MRI is clinically available, the present method is thought to be useful in view of its relative simplicity in eliminating the digestive tract signal on T_2 weighted images.