Masaru Komori

A novel method for analysis of the periodicity of chondrogenic patterns in limb bud cell culture: Correlation of in vitro pattern formation with theoretical models

To experimentally examine whether the pattern changes predicted by theoretical models of pattern formation actually occur in a limb bud cell culture system, we developed a practical method to automatically measure the periodicity of chondrogenic patterns in vitro. The method utilizes binary image processing to quantify the total number of peak and valley pixels in a pattern to obtain the average interval between stripes in the chondrogenic pattern, and we named it the peak length method. The reliability of the peak length method was examined by using computer simulation results. The peak length method enabled us quantitatively obtain the average interval between chondrogenic islands, and the values obtained by this method were closely correlated with the average intervals obtained by manual measurement and two-dimensional Fourier transformation. The average intervals obtained by the peak length method were shown to be stable over a wide range of pattern variations that are frequently observed in actual experiments. By applying the peak length method to actual experimental data, we compared the validity of two theoretical models of pattern formation (cell sorting model and reaction-diffusion model) and it was concluded that the peak-length method is a useful tool to quantitatively analyze chondrogenic patterns in limb micromass culture and to relate theoretical predictions and experimental results of pattern formation.

Keyhole method for high-speed human cardiac cine MR imaging.

Although electrocardiographic (ECG)‐gated magnetic resonance (MR) imaging is widely used for cardiac imaging, it has several disadvantages, such as long imaging time, respiratory artifacts, and motion artifacts induced by arrhythmia. An MR image can be acquired within about 0.3 seconds by using a fast gradient‐echo imaging method. When this method is continuously applied, only two to three images can be obtained during a single cardiac cycle. The goal of this study is to obtain cine MR images in a single cardiac cycle using fast gradient‐echo imaging combined with the “keyhole” method. The optimal conditions for the keyhole method for cardiac cine imaging were obtained by computer simulation based on a simplified cardiac model. When the read‐out direction was set parallel to the cardiac short axis, left ventricular motion was almost correctly reproduced by the keyhole method with acquisition time reduced to one‐fourth. J. Magn. Reson. Imaging 1999;10:778–783.

PACS Development At Kyoto University Hospital: Toward integrating digital imaging modalities.

The PACS project at Kyoto University Hospital in 1988 is reported in this paper. The old PAC system (KIDS: Kyoto univ. hosp. Image Database and communication System) developed since 1985 was reorganized and has been expanded to include several major digital imaging modalities such as X-ray CT, MRI, DSA and CR. The purpose of the new system (new KIDS) is to achieve the film-less environment in the field of neuro-radiology and evaluate the feasibility of the hospital wide PAC system. System configuration and present status are described. The newly designed fiber optic local area network and the new high-speed image workstation with 6 CRT screens are also mentioned.

Present status and performance of PACS at Kyoto University Hospital

A pilot PACS project, named KIDS, has been running in Kyoto University Hospital. The purpose of the system is to establish a small PACS that includes all digital imaging modalities and to evaluate it. The project has been continued from the first phase (KIDS-1) to the second phase (KIDS-2). In the first phase, a small-scale PACS was developed. In the second phase, the expansion of coverage of modalities and completion of the image database was intended. At present, the database contains image data of 16264 patients amounting to 150 Gbytes. Simulation of the retrieval process to the database shows that 154.3 s per patient is required for retrieving his/her entire image data. This calculated value is close to the actual time.

Off-line image exchange between two PACS modules using the "ISAC" magneto-optical disk

In order to exchange digital imaging data between two independent PACS modules, the ISAC (Image Save And Carry: JPACS/MEDIS-DC) formatted 130-mm magneto-optical disk (MOD) was used as an interchangeable off-line data transferring and recording medium. This system can provide the means for connecting distributed image databases and is useful for clinical studies.

Present status of PACS at Kyoto University Hospital: image workstation for clinical education

The PAC system: KIDS (Kyoto University Hospital Image Database and Communication System) has been expanded to include several major digital imaging modalities such as X-ray CT, MRI, DSA and CR. The fiber optic high-speed local area network and the workstation with quick image handling are newly designed. The system (new KIDS) is intended to achieve a film-less environment in the department of radiology and to evaluate the feasibility of a hospital-wide PAC system. The present status of the system at the end of 1989 including a image workstation installed in a lecture hall for clinical education is described.

Role Of Image Based Information In Patient Care: Problem Definition Pathology And Laboratory Medicine

Histological image and ECG are the typical image based information in pathology and laboratory medicine. n nIn this paper, two image based subsystems for histological and ECG examinations in a hospital information network of Kyoto university are described.

Teleconference system composed of super-high-definition image system and B-ISDN

This paper describes a system to carry out a medical conference between two remote places. Most kinds of medical images for a patient with circulatory-organ disease are filed in a super-high-definition image system, and the quality of these images and the maneuverability of the system were evaluated by medical experts. The results show that the qualities of all of the images and the maneuverability of the system satisfy the medical requirements. Further, a wide-band ISDN which has this system at two terminals in remote places has been constructed. The delay time, protocol analysis, and subjective evaluation of this system have been obtained, showing its good feasibility.

A measurement system for the behavior of children with developmental disorder using an omnidirectional camera

In the evaluation of children with developmental disorder, such as autism and learning disabilities (LD), an interview and behavior observation by a doctor or a clinical psychologist, as well as the hearing or behavior checklist completed by the parent or classroom teacher, are employed. Those, however, cannot be quantitative, and it is difficult to analyze in detail the long-term observation or effectiveness of education or therapy. From such a viewpoint, it is desired to establish a method that can measure the behavior of the child on a more objective and quantitative basis. As a means of behavior measurement, the child may carry a transmitter or a marker, but a child with a developmental disorder often rejects an instrument that directly touches the body, which makes the application difficult. A wide-angle camera may be employed, but its use is not simple, such as the need for calibration at the site of installation. In this study, a noncontact behavior measurement system is constructed, in which an omnidirectional camera with a hyperbolic mirror is used to determine the spatial position of the child in an objective and quantitative way. Using the constructed system, the behavior of the child with a developmental disorder is examined, and characteristic patterns are observed. It is concluded that the result of such a measurement can be a useful index in the evaluation of the observation of the course of the child with a developmental disorder, as well as in the evaluation of the effectiveness of education or therapy.

Digitized Portal Images: The Effect of Pixel Size on the Detection of Setup Errors in Radiation Therapy

In order to determine how large pixel size was acceptable for digitized portal images in radiation therapy, the sensitivity and specificity to detect setup errors were compared between the original portal images and digitized images. One hundred portal images were selected from the clinical cases, a half of which showed setup errors. Three radiotherapists were asked to find any setup error in the original images and three sets of digitized version of them (2,048 x 2,048,1,024 x 1,024, and 512 x 512 matrix). Digital images of 512 x 512 matrix showed significantly low sensitivity and specificity as compared with other images. Digitization into 1,024 x 1,024 matrix images with 350 pm spot size are acceptable for portal images in radiation therapy.