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Volume 25 (2008)
- Issue 4 Pages 70-
- Issue 3 Pages 37-
- Issue 2 Pages 22-
- Issue 1 Pages 1-
Volume 25, Issue 1
Displaying 1-4 of 4 articles from this issue
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Hidetake YABUUCHI, Takeshi KAMITANI, Yoshio MATSUO, Taro SETOGUCHI, Sh ...2008 Volume 25 Issue 1 Pages 1-4
Published: May 01, 2008
Released on J-STAGE: May 22, 2008
JOURNAL FREE ACCESSWe reported the performance of teleradiology system in screening mammography. We also examined the diagnostic accuracy between single reading with CAD and blind double reading using teleradiology system. Blind double reading showed higher diagnostic performance than single reading with CAD in the detection of clinically occult breast cancer. The teleradiology system is recommended in the institutions that have only single experienced reader of screening mammograms.View full abstractDownload PDF (2056K) -
Development and Clinical ApplicationTakashi YOSHIURA, Seiji KUMAZAWA, Tomoyuki NOGUCHI, Akio HIWATASHI, Os ...2008 Volume 25 Issue 1 Pages 5-8
Published: May 01, 2008
Released on J-STAGE: May 22, 2008
JOURNAL FREE ACCESSDiffusion-tensor(DT)tractography is an image analysis method that allows for visualization of specific white matter tract in the brain in vivo. This new technique has been used to visualize the pyramidal tract, which conveys electrical signal from neurons in the primary motor cortex to the spinal cord, in planning for brain tumor surgery. Conventional tractography based on the “streamline” method only partially visualizes the pyramidal tract because of fiber crossing with other white matter tracts. To overcome the crossing-fiber problem, we developed a new tractography method which is based on directional diffusion function(DDF). We applied DDF tractography method to MRI data of brain tumor patients as well as healthy subjects, and found that DDF-based method was able to visualize the pyramidal tract to a larger extent than conventional techniques do, and that the estimated tracts were consistent with anatomical knowledge. To further validate the DDF-based tractography method, we studied the somatotopic organization of the pyramidal tract in the posterior limb of the internal capsule(PLIC). Estimated organization of the fiber bundles of the pyramidal tract in the PLIC was consistent with anatomically known somatotopic organization, which supported the validity of the DDF-based tractography method.View full abstractDownload PDF (558K) -
Tatsuhiko IWASE, Michitaka HONDA, Osamu TOYAMA2008 Volume 25 Issue 1 Pages 9-17
Published: May 01, 2008
Released on J-STAGE: May 22, 2008
JOURNAL FREE ACCESSThe purpose of this investigation is the improvement of the X-ray diagnostic performance by adding the information of the mean energy. In the first stage of the investigation, the resolution of the mean energy was estimated by the theoretical calculation of the continuous x-ray energy spectrum distribution. This result showed that the difference of the mean energy between the water thickness of 20 and 21cm can be detected with SNR of >1.0 at the condition of 100kV and 10mAs. In the next stage, a multi-energy method was discussed as a realistic method to estimate the mean energy imaging from x-ray images acquired with different tube voltages. This method degrades the SNR of the mean energy by around 50% from the result of the continuous spectrum due to several approximations in the approximation processes. However, in the image test using the actual x-ray images acquired with 3-voltage method, the SNR of the mean energy can be improved by the digital smoothing filtration technique, which suggests that the multi-energy method is possibly applicable to clinical cases without increasing patient dose. The detailed evaluation of this method with using objects that is close to the human body is planned as our subsequent work.View full abstractDownload PDF (655K) -
Tatsuro HAYASHI, Xiangrong ZHOU, Huayue CHEN, Takeshi HARA, Hiroshi FU ...2008 Volume 25 Issue 1 Pages 18-21
Published: May 01, 2008
Released on J-STAGE: May 22, 2008
JOURNAL FREE ACCESSThe lung structures including airway tree, lung lobes and pulmonary segments are important information that are required by the development of computer-aided diagnosis systems. The structure of airway tree is the most important key point and provides the basic information for recognizing the lung lobe and lung segments. However, automated extraction and recognition of airway trees are difficult and the prior knowledge for supporting the extraction is expected. In this research, the distributions of angle, length, and diameter of airways in different branches were investigated using X-ray CT images from 50 patient cases. The experimental results showed that directions of each bronchial branch of airway regions in 50 CT cases distributed within a range of ±30 degrees, and the decreasing ratio of airway diameter between the child/parent bronchial branch was 0.7-0.8. These results showed that the possibility of sequentially estimating the direction and diameter of airway tree from parent bronchial branch to its child bronchial branches may be useful for extraction and recognition of the airway trees in CT images.View full abstractDownload PDF (631K)
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