189 research outputs found
Kakutani Dichotomy on Free States
Two quasi-free states on a CAR or CCR algebra are shown to generate
quasi-equivalent representations unless they are disjoint.Comment: 12 page
<Study 2> Saccadic eye movements and regional cerebral blood flow in schizophrenic patients.
This study examined tracking eye movements on predetermined stationary targets inpatients with schizophrenia spectrum dis order.The targets were 8 black points or 8 arabics\u27 numbered points placed on the circumference of a circle.Self-paced eye movements during clockwise tracking of these points by 23 patients and 23 normal controls were recorded using an infrared eye-mark recorder.Eye movements were an alyzed at two settings : first, when "fixation point" was defined as a point at which a gaze was held for at least 200 msec, and second, when held for at least 100 msec.The results indicated that at the 200 msec setting schizophrenic patients track with significantly fewer correct scores and more deviant scores than controls under black-point conditions.At the 100-msec setting, however, the correct scores of the patients were not significantly different from those of the controls, although the patients displayed more aberrant paths than the controls.The superfluous fixations in the patients improved significantly under numbered-point conditions, but patients still achieved lower correct scores than the controls. Four of the 23 patients exhibited centering (aberrant path directed toward the center point), suggesting immature control of eye movements under black-point conditions but not numbered-point conditions.These results suggest that some schizophrenic patients viewed the targets too quickly and that they have impaired directed attention, which can be improved by cues, and may have impaired preprogramming of eye movements, which is not improved by external cues.This study examined saccadic eye movements using simple stationary targets, in schizophrenic patients.The targets were 8 black points or 8 arabic-numbered points placed in randomized order on the circumference of a circle.Self-paced eye movements during clockwise tracking of these points, by 23 patients and 23 controls, were recorded using an infrared eye-mark recorder.Then the relationship between the saccades and clinical syndromes was investigated. Finally, the relationship between the performance of the saccades and resting regional cerebral blood flow (rCBF) was examined using single photon emission computed tomography with 99mTc-hexamethyl propyleneamine oxime (HMPAO).The results indicate that patients track with significantly fewer correct scores and more deviant scores than controls, in agreement with our previous study.There were two groups of patients : an ordinary group who obtained a full target hitting score at a 200 ms setting and a fast group who obtained the full score at 100 ms but not at 200 ms.Some patients displayed significantly more hypermetria than controls.Significant correlations were found between alienation syndrome (auditory hallucination and disturbance of the self) and correct scores, or delusion syndrome and deviant score.With respect to relative rCBF, fast group patients showed significantly decreased rCBF in the left limbic and inferior parietal areas as compared with ordinary group patients.These findings suggest that some schizophrenic patients view the stationary targets too fast and this may be related to dysfunction in the limbic-parietal association area in the left hemisphere.富山医科薬科大学・博士(医学)・乙第283号・松井三枝・1995/6/28富山医科薬科大
Development of a cardiac evaluation method using a dynamic flat-panel detector (FPD) system: A feasibility study using a cardiac motion phantom
金沢大学大学院医学系研究科量子医療技術
A computer-aided temporal and dynamic subtraction technique of the liver for detection of small hepatocellular carcinomas on abdominal CT images
金沢大学大学院医学系研究科量子医療技術学It is often difficult for radiologists to identify small hepatocellular carcinomas (HCCs) due to insufficient contrast enhancement. Therefore, we have developed a new computer-aided temporal and dynamic subtraction technique to enhance small HCCs, after automatically selecting images set at the same anatomical position from the present (non-enhanced and arterial-phase CT images) and previous images. The present study was performed with CT images from 14 subjects. First, we used template-matching based on similarities in liver shape between the present (non-enhanced and arterial-phase CT images) and previous arterial-phase CT images at the same position. Temporal subtraction images were then obtained by subtraction of the previous image from the present image taken at the same position of the liver. Dynamic subtraction images were also obtained by subtraction of non-enhanced CT images from arterial-phase CT images taken at the same position of the liver. Twenty-one of 22 nodules (95.5%) with contrast enhancement were visualized in temporal and dynamic subtraction images. Compared with present arterial-phase CT images, increases of 150% and 140% in nodule-to-liver contrast were observed on dynamic and temporal subtraction images, respectively. These subtraction images may be useful as reference images in the detection of small moderately differentiated HCCs. © 2006 IOP Publishing Ltd
Long-Term Outcome of Endoscopic Balloon Dilation in Obstructive Gastrointestinal Crohn's Disease: A Prospective Long-Term Study
Background The short- and long-term results of balloon dilation therapy in Crohn's
patients with non-anastomotic obstructive gastrointestinal lesions are investigated
Breathing chest radiography using a dynamic flat-panel detector combined with computer analysis
金沢大学大学院医学系研究科保健学専攻Kinetic information is crucial when evaluating certain pulmonary diseases. When a dynamic flat-panel detector (FPD) can be used for a chest examination, kinetic information can be obtained simply and cost-effectively. The purpose of this study was to develop methods for analyzing respiratory kinetics, such as movement of the diaphragm and lung structures, and the respiratory changes in x-ray translucency in local lung fields. Postero- anterior dynamic chest radiographs during respiration were obtained with a modified FPD, which provided dynamic chest radiographs at a rate of 3 frames/s. Image registration for correction of physical motion was followed by measurement of the distance from the lung apex to the diaphragm. Next, we used a cross-correlation technique to measure the vectors of respiratory movement in specific lung areas. Finally, the average pixel value for a given local area was calculated by tracing the same local area in the lung field. This method of analysis was used for six healthy volunteers and one emphysema patient. The results reported here represent the initial stage in the development of a method that may constitute a new method for diagnosing certain pulmonary diseases, such as chronic obstructive pulmonary disease, fibroid lung, and pneumonia. A clinical evaluation of our method is now in progress. (C) 2004 American Association of Physicists in Medicine
Pulmonary blood flow evaluation using a dynamic flat-panel detector: Feasibility study with pulmonary diseases
金沢大学医薬保健研究域保健学系Purpose: Pulmonary ventilation and circulation dynamics are reflected on fluoroscopic images as changes in X-ray translucency. The purpose of this study was to investigate the feasibility of non-contrast functional imaging using a dynamic flat-panel detector (FPD). Methods: Dynamic chest radiographs of 20 subjects (abnormal, n = 12; normal, n = 8) were obtained using the FPD system. Image analysis was performed to get qualitative perfusion mapping image; first, focal pixel value was defined. Second, lung area was determined and pulmonary hilar areas were eliminated. Third, one cardiac cycle was determined in each of the cases. Finally, total changes in pixel values during one cardiac cycle were calculated and their distributions were visualized with mapping on the original image. They were compared with the findings of lung perfusion scintigraphy. Results: In all normal controls, the total changes in pixel value in one cardiac cycle decreased from the hilar region to the peripheral region of the lung with left-right symmetric distribution. In contrast, in many abnormal cases, pulmonary blood flow disorder was indicated as a reduction of changes in pixel values on a mapping image. The findings of mapping image coincided with those of lung perfusion scintigraphy. Conclusions: Dynamic chest radiography using an FPD system with computer analysis is expected to be a new type of functional imaging, which provides pulmonary blood flow distribution additionally. © CARS 2009
A long-forgotten ‘dinosaur’ bone from a museum cabinet, uncovered to be a Japan\u27s iconic extinct mammal, Paleoparadoxia (Desmostylia, Mammalia)
Here, we report a new ‘discovery’ of a desmostylian fossil in the geological collection at a national university in Japan. This fossil was unearthed over 60 years ago and donated to the university. Owing to the original hand-written note kept with the fossil in combination with interview investigation, we were able to reach two equally possible fossil sites in the town of Tsuchiyu Onsen, Fukushima. Through the interviews, we learned that the fossil was discovered during construction of a debris flow barrier and that it was recognized as a ‘dinosaur’ bone among the locals and displayed in the Village Hall before/until the town experienced a fire disaster in 1954. As scientific findings, the fossil was identified to be a right femur of Paleoparadoxia (Desmostylia), which shows well-preserved muscle scars on the surface. The age was estimated to be 15.9 Ma or younger in zircon-dating. This study shows an excellent case that historical and scientific significances could be extracted from long-forgotten uncatalogued specimens as long as the original information is retained with the specimens
Development of pulmonary blood flow evaluation method with a dynamic flat-panel detector: quantitative correlation analysis with findings on perfusion scan
金沢大学医薬保健研究域保健学系Pulmonary blood flow is reflected in dynamic chest radiographs as changes in X-ray translucency, i.e., pixel values. Thus, decreased blood flow should be observed as a reduction of the variation of X-ray translucency. We performed the present study to investigate the feasibility of pulmonary blood flow evaluation with a dynamic flat-panel detector (FPD). Sequential chest radiographs of 14 subjects were obtained with a dynamic FPD system. The changes in pixel value in each local area were measured and mapped on the original image by use of a gray scale in which small and large changes were shown in white and black, respectively. The resulting images were compared to the findings in perfusion scans. The cross-correlation coefficients of the changes in pixel value and radioactivity counts in each local area were also computed. In all patients, pulmonary blood flow disorder was indicated as a reduction of changes in pixel values on the mapping image, and a correlation was observed between the distribution of changes in pixel value and those in radioactivity counts (0.7 ≤ r, 3 cases; 0.4 ≤ r < 0.7, 7 cases; 0.2 ≤ r < 0.4, 4 cases). The results indicated that the distribution of changes in pixel value could provide a relative measure related to pulmonary blood flow. The present method is potentially useful for evaluating pulmonary blood flow as an additional examination in conventional chest radiography. © 2009 Japanese Society of Radiological Technology and Japan Society of Medical Physics
- …