All issues
Volume 12 (1995)
- Issue 3 Pages 107-
- Issue 2 Pages 68-
- Issue 1 Pages 1-
Volume 12, Issue 2
Displaying 1-4 of 4 articles from this issue
- |<
- <
- 1
- >
- >|
-
Hitoshi Ueda, Hiroshi Fujita, Tokiko Endo, Tomoko Matsubara, Katsuhei ...1995 Volume 12 Issue 2 Pages 68-73
Published: 1995
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSWe developed a new automated detection algorithm for spicules on digital mammograms. After the background trend around the detected mass was removed by curve fitting technique, highfrequency components were enhanced by using an unsharp-mask filter. The detection was performed by using a newly developed "pendulum filter" in three steps for examining the existance of spicules, searching the thick and/or thin spicules and finding the inner components in the mass. The pendulum filter detected most of the spicules that pointed out by a radiologist. The sensitivity and specificity of our algorithm for detecting the existance of spicules in the mass were 86.7% and 86.7%, respectively, in our database of 30 mammograms.View full abstractDownload PDF (6275K) -
Du-Yih TSAI, Hitoshi KOGISO, Kou FUJISAWA, Kensaku KAGAWA, Masaaki TOM ...1995 Volume 12 Issue 2 Pages 74-81
Published: 1995
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSWe have previously proposed an efficient method for automated measurement of right and left ventricular volumes in MR images. This provided useful information for globally evaluating mechanical function of the heart. Namely, the proposed method was effective for discrimination of function normality and abnormality using the difference of ventricular volumes at end-diastole and end-systole states. In this paper, we describe an approach by applying the centerline method to characterizing regional ventricular function. With this method the location of wall motion abnormality can he identified. The results obtained demonstrate the power and potential of this method in assessment of ventricular function. This method of regional wall motion analysis, combined with our previously proposed method of global classification analysis, may provide more information for medical doctors to make more accurate diagnosis.View full abstractDownload PDF (3208K) -
Kenichi Hirako, Hiroshi Fujita, Tokiko Endo, Katsuhei Horita, Choichir ...1995 Volume 12 Issue 2 Pages 82-90
Published: 1995
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSWe have improved our automated detection algorithm for clustered microcalcifications on digital mammograms by adding two techniques. In our schemes, vectors of density gradient are firstly calculated within the area of breast which is segmented automatically. Second, the "triple-ring filter"extracts the specific features for the pattern of microcalcification from the vectors. Third, the shape analysis is performed. As one of new parts, a region growing technique, in which the information of vector intensity is employed to calculate the variable thresholding values, is used to determine the correct region of the microcalcification. The contrast analysis part is also added in order to reduce the false-positive candidates. The sensitivity of our revised algorithm is 87.3% with 0.55false detection of cluster per image in our database of 163 mammograms.View full abstractDownload PDF (2807K) -
Nobuyuki NAKAMORI, Tooru SUDOU, Hitoshi KANAMORI, Masahiro ENDO, Masah ...1995 Volume 12 Issue 2 Pages 91-99
Published: 1995
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSScatter to primary radiation ratios at detector position were calculated for cylindrical water phantoms in corn-beam 3D-CT scanner using the Monte Carlo simulation method. A quantity of scatter reached on detector was large and was nearly twice as much as that of primary at the center of cylindrical water phantom with radius of 10 cm, A large quantity of scatter in projection data caused a decrease in CT numbers of reconstructed images and cupping effects were obserbed. When the x-ray photons exposed unformly on phantom with bow-tie filter, the scattered radiation was decreased to half and the cupping effects were not obserbed. While CT numbers in the whole region of images were reduced and roundedoff images were reconstructed.View full abstractDownload PDF (3397K)
- |<
- <
- 1
- >
- >|