Biomedical subjects

T Kozuka

Publications and source records attributed to T Kozuka.

At least 73 records · Page 4Linked to original sources

PubMed1994

Initial data-element selection for the evaluation of picture archiving and communication system performance.

The completely new, hospital-wide picture archiving and communication system (PACS) now being implemented at Osaka University Hospital is described elsewhere in this issue. This paper lists the many studies of the department and hospital that were performed before the PACS for the purpose of identifying data elements for use in evaluating a PACS system. A second purpose of the initial data-element collection was to assist in the overall Osaka University PACS design. Selected studies from this work are presented here.

Computer Systems↗

PubMed1994

A comparison of conventional screen-film radiography and hard copy of computed radiography in full and two-thirds sizes in detection of interstitial lung disease.

This study examined whether hard-copy radiographs produced from computed radiography (CR) images show the subtle interstitial pulmonary disease equally well to conventional screen-film radiographs, because a digital radiography should be chosen for introduction of the digital picture archiving and communication system (PACS) for the new Osaka University Hospital. Eleven radiologists examined 20 abnormal and 20 control chest radiographs presented in each of three groups: conventional screen-film radiographs and two sizes of hard-copy radiographs made from CR images. This study of digital image quality of chest examinations found that some findings on conventional screen-film radiography images are not reproduced by current CR (2,000 x 2,000 x 10 bits in matrix), especially when the experienced radiologists were observed. This finding suggested improvements are needed in CR before CR of chest should fully replace conventional screen-film radiography.

Hospitals, University↗

PubMed1994

PACS in Osaka University Hospital.

To develop the hospital information system, the radiological information system, and the picture archiving and communication system for our new hospital, we analysed the data volume at each step of the flow in our present film-based system. After that, we used a small PACS, and it indicated the problems in it. From the analysis of the data volume of the film-based system, it was found out that digital data should be compressed, and prefetching techniques should be employed for digital PACS. Several types of display terminals had been proved to be necessary for different purposes. An RIS connection was thought to be obligatory to avoid incorrect input of ID on the image. Image input terminals should have edit functions for easy recognition of the image information. Taking account of these requirements for digital PACS, we are developing an actual total PACS.

Computer Terminals↗

PubMed1994

Technology assessment of PACS in Osaka University Hospital.

This paper describes a methodology of PACS technology assessment and gives examples of the results of measurement of 24 items of PACS-related situations of image diagnosis systems in Osaka University Hospital before a PACS is installed. These data are to be compared with the data which will be measured after PACS is installed in the new Osaka University Hospital, in order to complete our technology assessment. We propose common variables, units, and conditions of measurement, in order to establish a standard method of data comparison between before and after PACS installation in hospitals at large. We designed our PACS taking technology assessment into account. We do not stop the technology assessment at the efficacy evaluation, because PACS must be more than a tool for radiological practice. We extend the technology assessment into the effectiveness evaluation, so that PACS is a part of radiological practice itself, and diagnostic accuracy, economy and efficiency are the results of PACS operation.

Diagnostic Imaging↗

PubMed1994

Image quality of digital chest radiography: evaluation of subtle interstitial lung abnormalities (preliminary study).

To evaluate the image quality of storage phosphor radiography (SR) for diagnosing subtle interstitial lung abnormalities, we studied the differences between conventional screen-film radiography (FR) and SR in 38 patients. Nineteen patients had subtle interstitial lung abnormalities and the others had normal chests. Two formats of hard copies were used for SR; a full-size SR (14 x 14 inches, 0.2-mm pixel size) and a minified SR (9 x 9 inches, 0.13-mm pixel size). Readings were carried out by 14 readers (7 chest radiologists and 7 residents). The area under the receiver operating characteristic curve was used to evaluate the results. For the 14 readers no significant differences in observer performance were observed among the three image sets (FR, full-size SR, minified SR), while for the seven chest radiologists significant differences were observed between FR and the two formats of SR. The best perceptual accuracy was obtained with FR as evaluated by the seven chest radiologists. In conclusion, while overall performance with digital and conventional radiographs was almost the same as far as diagnosing subtle interstitial lung abnormalities, significant differences between FR and SR were found by chest radiologists. Critically important information may be lost in commercially available SR.

Humans↗

PubMed1994

Development and evaluation of oral reporting system for PACS.

Experimental workstations for oral reporting and synchronized image filing have been developed and evaluated by radiologists and referring physicians. The file media is a 5.25-inch rewritable magneto-optical disk of 600-Mb capacity whose file format is in accordance with the IS&C specification. The results of evaluation tell that this system is superior to other existing methods of the same kind such as transcribing, dictating, handwriting, typewriting and key selections. The most significant advantage of the system is that images and their interpretation are never separated. The first practical application to the teaching file and the teaching conference is contemplated in the Osaka University Hospital. This system is a complete digital system in terms of images, voices and demographic data, so that on-line transmission, off-line communication or filing to any database will be easily realized in a PACS environment. We are developing an integrated system of a speech recognizer connected to this digitized oral system.

Education, Medical↗

PubMed1994

Evaluation of the radiographic efficacy of iomeprol.

Iomeprol, a new nonionic contrast medium, was administered at concentrations of 300 mgI/ml, 350 mgI/ml, and 400 mgI/ml to 1939 Japanese patients. The radiographic efficacy, the incidence of heat sensation and the incidence of pain were evaluated. The radiographic efficacy was rated as excellent in 80.6% and good in 17.5% of 1017 cases of conventional arteriography, excellent in 75.6% and good in 22.2% of 267 cases of IADSA or IVDSA, excellent in 78.3% and good in 19.6% of 384 cases of intravenous urography and excellent in 68.6% and good in 28.8% of 271 cases of CT enhancement. There was no statistical difference in radiographic efficacy between the sites of arteriography. Heat sensation was mild or moderate in 43.4% and severe in 0.2% of cases requiring intra-arterial injection, and mild or moderate in 50.7% of cases requiring intravenous injection. There were no cases of severe heat sensation following intravenous injection. The incidence of pain was low (mild 4.2%, moderate 0.7% and severe 0.1%) with intra-arterial injections. It is concluded that iomeprol is an excellent radiographic contrast medium for intravenous urography, CT enhancement and various forms of angiography.

Adolescent↗

PubMed1994

Assessment of the side-effects of iomeprol.

Adverse reactions were investigated in a group of 1918 patients enrolled in a study for the clinical assessment of iomeprol. The incidence of adverse reactions in the group was 5.3%. Dermatological symptoms were the principal adverse reactions. No previously unreported side-effects from iodinated contrast media were detected. Most adverse reactions were of slight or moderate intensity and most appeared within 3 h of the injection. The examinations which elicited a comparatively high frequency of adverse reactions were cerebral angiography, abdominal angiography, peripheral angiography, intravenous urography and thoracic angiography. No significant sex differences were noted with respect to the occurrence of adverse reactions, but such effects were more frequent among younger patients, among patients with allergic conditions and among patients who had previously received iodinated contrast media. As regards the manner of injection of iomeprol, there were no definite trends in terms of the iodine concentration used or the quantity of contrast medium injected, but the incidence of adverse reactions was comparatively high for intravenous as compared with intra-arterial injection.

Adult↗

PubMed1994

High-resolution CT and pulmonary function tests in collagen vascular disease: comparison with idiopathic pulmonary fibrosis.

To estimate whether the lung abnormalities seen in collagen vascular diseases (CVD) were similar or distinct to those seen in idiopathic pulmonary fibrosis (IPF), and to ascertain whether the extent of the abnormalities on high-resolution CT (HRCT) correlated with pulmonary function, we reviewed HRCT findings and pulmonary function test results of 64 patients with either CVD (n = 55) or IPF (n = 9). Response to corticosteroid treatment was also evaluated in 20 of the 64. High incidence of honeycomb lesion was observed in IPF (9/9, 100%) and in progressive systemic sclerosis (PSS) (11/14, 79%). CVD, except for PSS, had a low incidence of honeycomb lesion (27%). On the other hand, incidence of ground-glass shadow in CVD (47/55, 85%) was the same as that in IPF (8/9, 89%). Diffusing capacity significantly correlated with the extent of all parenchymal abnormalities in all CVD and IPF, with honeycomb lesion in PSS, and with ground-glass shadow or air-space consolidation in CVD except for PSS (r < -0.7, P < 0.001). In all 15 cases in which corticosteroid therapy was effective, no honeycomb lesions were seen. Collagen vascular disease, except for PSS, had a different pattern of disease than IPF. The morphologic changes seen on HRCT correlated well with pulmonary function in CVD.

Collagen Diseases↗

PubMed1994

An image analyzing system for interstitial lung abnormalities in chest radiography. Detection and classification by Laplacian-Gaussian filtering and linear opacity judgment.

RATIONALE AND OBJECTIVES: The effectiveness of a computerized analysis system to detect and characterize interstitial lung abnormalities seen on chest radiographs was evaluated. This method included a process of four-directional Laplacian-Gaussian filtering and a process of linear opacity judgement. For quantitative analysis of interstitial opacities, the radiographic index, which is the percentage of opacity areas in a region of interest, was obtained and evaluated in the images. These opacities represented interstitial lung abnormalities. METHODS: Two regions of interest were selected in each right lung of 50 patients with normal lung parenchyma and 50 patients with diffuse interstitial lung abnormalities, confirmed with high-resolution computed tomography. These regions of interest were processed by our computerized analysis system. RESULTS: Abnormal lungs were well differentiated from normal lungs by the radiographic indices obtained from the images filtered by four-directional Laplacian-Gaussian filters and from those processed by linear opacity judgement. However, honeycomb lesions and other interstitial abnormalities (interstitial changes other than honeycombing) were differentiated from each other only by the radiographic indices obtained from the image processed by linear opacity judgment (P < .05). DISCUSSION: These results indicate that this system is useful for the detection and characterization of interstitial lung abnormalities.

Female↗

PubMed1994

Transthoracic percutaneous ethanol injection into the liver.

RATIONALE AND OBJECTIVES: The feasibility of the new transthoracic approach of percutaneous ethanol injection through the lower lung to the subphrenic region of the liver was evaluated in normal rats. METHODS: Fourteen normal rats received percutaneous ethanol injection. A 22-gauge fine needle was inserted into the liver via the thoracic cage and through the lower lung parenchyma under computed tomographic (CT) guidance. After ethanol (0.1-0.2 mL) was injected, three follow-up CT scans were performed: immediately after, 1 day after, and 1 week after the initial injection. All animals were killed 1 week after injection to evaluate macroscopic changes of the diaphragm and pleura. RESULTS: No major complications were observed. Minor complications were observed in six rats; these included one pneumothorax (7%) and five band-like and streaky shadows (presumably pulmonary hemorrhages) (35%) on the CT scan obtained immediately after the procedure. However, all complications had disappeared spontaneously in the follow-up CT scan obtained 1 day after the procedure. At autopsy, no pleural changes were seen. CONCLUSIONS: This study demonstrates that percutaneous ethanol injection through the lower lung parenchyma is achievable. Although this study was performed only in normal rats, the transthoracic approach can be a complementary method of ultrasound-guided percutaneous ethanol injection for tumors in the subphrenic region of the liver. Further study will be needed in abnormal livers and then in human subjects to verify the safety and efficacy of this procedure.

Animals↗

PubMed1994

Time-of-flight MR angiography of portal system and collaterals in portal hypertension using a 2-DFT fast spoiled gradient recalled steady-state precession technique.

MR angiographic examinations were performed in 26 patients. Approximately 30 contiguous fast spoiled GRASS images (8.1/3.1/30 degrees, TR/TE/flip angle) were acquired during single breath-holding for about 35 s, and then new images were reconstructed with maximum intensity projection technique. Spoiled GRASS images (40/12/40) of 2 to 3 slices were taken during breath-holding for about 13 s, and these processes were repeated to obtain about 30 individual images for conventional MR angiography. The new MR angiograms were compared quantitatively and qualitatively with conventional MR angiograms with arterial portography as the gold standard. The new MR angiograms could visualize blood vessels with smooth margins, and provided almost the same anatomic information about the portal vein and collateral vessels as the conventional MR angiograms. Contrast-to-noise ratios between the portal or hepatic vein and liver parenchyma were significantly higher with fast spoiled GRASS images. The new MR angiograms using fast spoiled GRASS images provided useful diagnostic mapping of the collateral venous pathways within a shorter examination time.

Adult↗

PubMed1994

[A comparative clinical study on the treatment of head and neck tumors by adjuvant chemotherapy with HCFU--Second Study by Kinki Head and Neck Tumor Study Group].

In the first study by the "Kinki Head and Neck Tumor Study Group," we performed a comparative study to investigate intergroup difference between a control group consisting of patients given radical treatment only, and a HCFU group consisting of patients receiving long-term administration of HCFU after radical treatment. We earlier reported that subsequent observations by stratification revealed a favorable tendency in the cumulative disease-free rate in Stage II and Stage III patients in the HCFU group. In the second study, the same methods of treatment as in the first study were compared in a prospective control study. No differences were found between the two groups in Stage II patients. In Stage III patients, however, the disease-free rate tended to increase significantly in the HCFU group as in the first study.

Adult↗

PubMed1994

MR appearance of Virchow-Robin spaces along lenticulostriate arteries: spin-echo and two-dimensional fast low-angle shot imaging.

PURPOSE: To delineate the appearance of normal Virchow-Robin spaces on routine spin-echo images and demonstrate the lenticulostriate arteries within them with a flow-sensitive fast low-angle shot (FLASH) pulse sequence. METHODS: Seventy subjects, free of cerebrovascular diseases and other neurologic disorders, ranging in age from 1 to 75 years, were examined. On a 1.5-T MR system, axial spin-echo images of 5 mm thickness were obtained in all subjects. In 45 of 70 subjects axial two-dimensional FLASH images of 3 mm thickness were continuously imaged. RESULTS: On T1- and spin density-weighted images Virchow-Robin spaces were detected as small foci of cerebrospinal fluid intensity around the anterior commissure in all subjects (100%), and in the basal ganglia at the level of the foramen of Monro in 40 (57%). T2-weighted images equally showed Virchow-Robin spaces around the anterior commissure but were less sensitive than T1- and spin-density weighted images at the level of the foramen of Monro (14%). Virchow-Robin spaces identified on T2-weighted images should be isointense with cerebrospinal fluid. However, one or two spaces in 11 younger subjects were hypointense relative to adjacent brain tissue. On FLASH images most Virchow-Robin spaces identified on spin-echo images were delineated as high-intensity foci, corresponding to lenticulostriate arteries. CONCLUSIONS: Normal Virchow-Robin spaces along the lenticulostriate arteries are frequently detected on spin-echo images. Their appearance, affected by the flow of associated lenticulostriate arteries, varies from hyper- to hypointensity to brain tissue on T2-weighted images. The two-dimensional FLASH sequence can demonstrate the flow of the arteries, thereby helping confirm that these are truly Virchow-Robin spaces.

Adolescent↗

PubMed1994

MR imaging of middle cerebral artery stenosis and occlusion: value of MR angiography.

PURPOSE: To investigate the effectiveness of MR angiography in conjunction with spin-echo imaging for evaluating vascular patency in patients with middle cerebral artery (MCA) stenosis or occlusion. METHODS: Seven patients with MCA stenosis or occlusion, verified with contrast angiography in five and correlated with transcranial Doppler sonography in two, were examined using two-dimensional and/or three-dimensional time-of-flight MR angiographic techniques as well as conventional spin-echo imaging. RESULTS: Of the seven patients, six demonstrated basal ganglionic and/or cortical infarct in the MCA territory. Except one case with minimal stenosis immediately distal to the MCA origin, all six cases with either severe stenosis or occlusion of the main trunk of the MCA showed the absence of normal flow voids using spin-echo imaging in the sylvian fissure on the affected side. However, it was not possible to discriminate between stenosis and occlusion. Although different mechanisms (ie, flow-induced spin dephasing for the 2-D technique and progressive spin saturation for the 3-D technique) were predominantly responsible for the loss of signal through the area of stenosis, both the 2-D and 3-D MR angiograms clearly depicted the compromised flow of the MCA: a focal discontinuity with decreased vessel caliber corresponded to stenosis, and nonvisualization of distal MCA branches represented occlusion. CONCLUSION: Either 2-D or 3-D time-of-flight MR angiography is a useful adjunct to conventional parenchymal spin-echo imaging for evaluating vascular patency in patients with MCA stenosis or occlusion, although it is important to recognize that each technique has a different basis for the loss of signal through the area of stenosis.

Adult↗

PubMed1993

[Development of oral reporting system in PACS environment].

An experimental radiologic reporting system using oral presentations has been developed and tested. The rewritable and compact magneto-optical disk (MOD) is employed to store oral diagnostic reports together with read radiologic images. The MOD is 5.25 inches in diameter, has a 600 MB memory capacity, and is erasable, light and compact. Advantages of the system are simultaneous retrieval of oral reports by a radiologist and the images he or she interpreted, and the capability of media circulation in addition to the function of filing. Thus MOD has a multimedia function of both off-line communication and filing. When medical images are interpreted and oral presentations are registered, automatically digitized oral reports and digitized images are filed in the MOD. Referring physicians can get oral diagnostic reports and can see the images at the same time on a personal computer. Furthermore, integration with voice recognition capability is being tried in our experiment.

Communication↗

PubMed1993

High-dose rate and low-dose rate intracavitary therapy for carcinoma of the uterine cervix. Final results of Osaka University Hospital.

BACKGROUND: High-dose rate (HDR) intracavitary radiation therapy for carcinoma of the uterine cervix has gradually found wider acceptance. In 1983, the authors first presented the results of prospective randomized comparative study of HDR versus low-dose rate (LDR) therapy. In the current study, the final results of this study with a longer follow-up are presented. METHODS: From January 1975 through August 1983, 430 previously untreated patients with carcinoma of the uterine cervix in Stages I-III were treated with either HDR 60Co therapy or LDR 137Cs therapy at our department. HDR was administered to a total of 259 patients: 32 patients in Stage I, 80 in Stage II, and 147 in Stage III. LDR was administered to a total of 171 patients: 28 patients in Stage I, 61 in Stage II, and 82 in Stage III. RESULTS: The 5-year cause-specific survival rates of Stage I-III patients treated with HDR were 85%, 73%, and 53%, respectively. The corresponding figures for LDR were 93%, 78%, and 47%, respectively. There was no significant difference between these survival rates. Moderate-to-severe complications developed in 10% of the patients treated with HDR and 4% of those with LDR. This difference in the incidence of complications was statistically significant (P = 0.023). CONCLUSIONS: Treatment results in terms of cause-specific survival were equivalent for HDR and LDR treatment. However, the incidence of complications was higher for the HDR group, although within acceptable levels, than for the LDR group.

Actuarial Analysis↗

PubMed1993

[Appearance of low intensity band seen around the abdominal organs on gradient echo image].

To clarify the mechanism of appearance of low intensity band seen around the abdominal organ, we performed phantom study. The resected intestine, which filled with water and fixed in the salad oil, was obtained by spoiled GRASS MR imaging with variable TEs and fixed TR. On in phase image, low intensity band was seen in low frequency side of frequency encoding direction of surface of the intestine, and high intensity band in high frequency side. On out of phase image, low intensity band is seen all around the intestine. Our phantom study verified that the appearance of low intensity band on out of phase gradient echo image is due to both the misregistration and signal void caused by chemical shift artifact.

Adipose Tissue↗