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Biomedical subjects

T Kozuka

Publications and source records attributed to T Kozuka.

At least 19 recordsLinked to original sources
PubMed1995

Interpretation of subtle interstitial chest abnormalities: conventional radiography versus high-resolution storage-phosphor radiography--a preliminary study.

To evaluate the reliability of digital chest radiography in diagnosing subtle interstitial lung abnormalities, we performed several clinical studies including a comparison of conventional screen-film radiography and storage-phosphor radiography (2 K x 2 K pixels, 10 bit), and a comparison of conventional screen-film radiography and film-digitized radiography (2 K x 2 K pixels, 10 bit). From these previous studies, a spatial resolution of 0.2-mm pixel size was considered inadequate to diagnose subtle interstitial lung diseases. Under these circumstances, the newly developed Fuji Computed Radiography system (FCR 9000; Fuji Photo Film, Tokyo, Japan) has recently become available. This system provides 0.1-mm pixel size (4 K x 5 K pixels, 10-bit depth) and life-size hard copies (14 x 17 inches). To evaluate the reliability of new high-resolution storage-phosphor radiography (FCR 9000) in diagnosing simulated subtle interstitial abnormalities (including simulated lines, micronodules, and groundglass opacities), the differences among radiologists in interpreting conventional screen-film radiographs and life-size high-resolution storage-phosphor radiographs were studied. Observation was made by eight experienced chest radiologists and receiver-operating characteristic (ROC) analysis was performed. There was no significant difference in detecting in subtle simulated interstitial abnormalities between conventional film-screen radiography and high-resolution storage-phosphor radiography. For all three types of abnormalities, there was no significant difference between conventional and storage-phosphor radiography. In conclusion, the high-resolution storage-phosphor chest radiography (0.1-mm pixel size, 10-bit depth) may be substituted for conventional chest radiography in the detection of subtle interstitial abnormalities.

Data Display↗
PubMed1995

Enhancement of hematopoietic uptake by granulocyte colony-stimulating factor in Ga-67 scintigraphy.

The authors report on two non-Hodgkin's lymphoma cases which showed markedly enhanced Ga-67 uptake of granulopoietic area induced by recombinant human granulocyte colony-stimulating factor (rhG-CSF) administration. The rhG-CSF is a newly developed agent for reduction of infections, which stimulates the proliferation and differentiation of granulopoiesis. Use of rhG-CSF is becoming increasingly frequent because the indications are so broad that most patients with intensive chemotherapy for malignancies benefit from undergoing this treatment. In this study, the results of the two cases were: 1) G-CSF enhanced the accumulation of Ga-67 citrate in the granulopoietic area; 2) the marked uptake of red marrow looked like involvement; and 3) in contrast, the involved area became relatively "cold." These findings should be considered in the interpretation of Ga-67 scintigraphy.

Adult↗
PubMed1995

Assessment of right ventricular regional contraction and comparison with the left ventricle in normal humans: a cine magnetic resonance study with presaturation myocardial tagging.

OBJECTIVE: Right ventricular regional contractility has been thought to be difficult to assess precisely. Cine magnetic resonance imaging with presaturation myocardial tagging was employed to quantitate the contraction of the right ventricular free wall and to identify normal performance compared with the left ventricle. METHODS: Nine normal volunteers, aged 27-39 years, were examined in a 1.5 Tesla superconductive magnet, and short axis and four-chamber sections at the mid-ventricular level were imaged with cine magnetic resonance sequences. Tags, applied at end diastole as two parallel black lines, intersected the mid-portion of the free wall, dividing it into upper, centre, and lower segments in the short axis section, and anterior, middle, and posterior segments in the four-chamber section. From a series of cine magnetic resonance images at 50 ms intervals over a cardiac cycle, end diastolic, and early, mid-, and end systolic images were chosen for calculation of the endocardial, epicardial, and mean percent fractional shortening (%FS) in the six segments. RESULTS: There was (1) a gradual increase in %FS in systole in both sections (P < 0.001, < 0.005); (2) a poor transmural gradient of contractility; (3) a predominance of meridional shortening (whole length, mean end systolic %FS (SD): short axis, 17.4 (3.1)%; four-chamber, 30.1 (4.1)%; P < 0.001) in contrast to dominant circumferential shortening in the left ventricular lateral wall; (4) lower predominance of contractility in the short axis section (P < 0.001), and a middle dip of contractility in the four-chamber section (P < 0.005). CONCLUSIONS: Heterogeneity of contractility was closely correlated with the myocardial fibre architecture, and with wall stress determined by its thickness and curvature. It was proved that right ventricular regional function could be analysed non-invasively using cine magnetic resonance imaging with myocardial tagging.

Adult↗
PubMed1995

Clinical evaluation of pulmonary nodules with single-exposure dual-energy subtraction chest radiography with an iterative noise-reduction algorithm.

PURPOSE: To compare the clinical usefulness of the single-exposure dual-energy subtraction method with an iterative noise-reduction algorithm. MATERIALS AND METHODS: Fourteen radiologists read three sets of images from 44 patients: original computed radiographic images only, original computed radiographic images plus conventional bone-subtracted images, and original computed radiographic images plus iterative noise-reduced bone-subtracted images. Twenty-two patients had one or more (maximum, five) pulmonary nodules; 22 had no pulmonary nodules. Observer performance was evaluated by means of calculation of the average area under the alternative free-response receiver operating characteristic curves (A1). RESULTS: Compared with the original computed radiographic image only, detection of nodules was significantly better with both the original computed radiographic image plus iterative bone-subtracted image (A1 = 0.72 +/- 0.02 and 0.66 +/- 0.02, respectively; P = .01) and the original computed radiographic image plus conventional bone-subtracted image (A1 = 0.66 +/- 0.02 and 0.61 +/- 0.01, respectively; P = .03). CONCLUSION: The iterative noise-reduction algorithm is superior to conventional methods in detection of pulmonary nodules.

Adolescent↗
PubMed1995

Detectability of hypervascular hepatocellular carcinoma by arterial phase images of MR and spiral CT.

The ability of arterial phase images of breath-hold MR imaging and spiral CT to detect hypervascular hepatocellular carcinomas (HCCs) was evaluated. Prior to transcatheter arterial chemoembolization (TACE) with iodized oil, MR images and spiral CT during i.v. bolus injection of contrast medium (IV-MR imaging and IV-spiral CT) and spiral CT during intraarterial injection of contrast media through catheter (IA-spiral CT) of the entire liver were obtained in 24 consecutive patients with 93 HCCs. In the detection of HCCs less than 1 cm in diameter, IA-spiral CT (87.3%) was superior to IV-MR imaging (63.5%) and IV-spiral CT (54.0%) (p < 0.001). There was no significant difference in detectability in any tumor size between IV-MR imaging and IV-spiral CT. IA-spiral CT was the best for detecting hypervascular HCCs, and there was no significant difference between IV-MR imaging and IV-spiral CT.

Adult↗
PubMed1995

Cervical invasion of endometrial carcinoma--evaluation by parasagittal MR imaging.

Twenty-seven consecutive patients were examined by T2-(1,800/70 ms) and postcontrast T1-weighted (600/15) spin echo (SE) or dynamic (200/15) SE MR imaging to determine the usefulness of parasagittal MR imaging in assessing cervical invasion of endometrial carcinoma. The images were obtained in a direction parallel to the longitudinal axis of the uterus (parasagittal). The cervical epithelium, being hyperintense on the late phase dynamic and postcontrast T1-weighted SE images, had disappeared partially or totally in all 4 patients with cervical invasion. The enhanced cervical epithelium was completely seen in one patient with the tumor protruding into the cervical canal in a polyp-like form without cervical epithelial invasion. The same was also seen in the 22 patients with the tumor remaining in the corpus cavity. The enhanced parasagittal MR images facilitated the evaluation of the extent of the endometrial carcinoma.

Adenocarcinoma↗
PubMed1995

[Detectability of hypervascular small hepatocellular carcinoma by dynamic spiral CT].

Thirty-one cases of small hepatocellular carcinoma (HCC) under 3 cm in diameter underwent Spiral CT with bolus injection of contrast medium (Dynamic Spiral CT). Dynamic Spiral CT was compared with CT after intra-arterial injection of iodized oil (Lipiodol-CT). The detectability of 79 nodules of small HCC on early phase images of Dynamic Spiral CT was 49.4% (32.6% for those under 1 cm in diameter, 58.3% for 1-2 cm, 91.7% for 2-3 cm). The detectability of small HCCs above the hilum of the liver was better than that below the hilum. Five lesions were detected only on delayed CT images, but not on early phase CT images. Dynamic Spiral CT is useful for detecting hypervascular small HCCs, and both early phase and delayed CT images must be obtained.

Adult↗
PubMed1994

Developing a new picture archiving and communication system for the new Osaka University Hospital.

Osaka University Hospital moved into a new hospital building on the suburban Suita campus in October 1993. A newly developed hospital information system, a new radiologic information system and phase I of a completely new Picture Archiving and Communication System (PACS) also began operating. Work began in 1986 on this PACS. The PACS effort has been guided by one working group and two committees during the last 7 years. A survey of the previous diagnostic and image delivery system was performed as part of the preamble to designing an optimal PACS. Extensive analysis and measurement of pre-existing operational conditions was undertaken. These studies and technical research projects are described in a companion paper in this issue. The phase I hardware installation and initial testing were completed in March 1994. Subsequent phases will build incrementally until the completely new, hospital-wide PACS is realized.

Computer Systems↗
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↗