Biomedical subjects

T Ishigaki

Publications and source records attributed to T Ishigaki.

At least 19 recordsLinked to original sources

PubMed1996

Estimation of the size of the media necessary to construct a medical image database.

To estimate the size of the media necessary to construct a medical image database, a statistical analysis was made of the radiological data in our hospital information system database. The distribution of the total radiological image data storage required during one working day can be regarded as a normal distribution, and the distribution per patient was different from a normal one. Therefore, the mean amount required for the data storage of radiological images during one working day is very useful in estimating the data storage required for radiological images during a given number of working days.

Computer Systems↗

PubMed1996

Non-Hodgkin's lymphoma of the thyroid. A clinical study of twenty-two cases.

Non-Hodgkin's lymphoma (NHL) of the thyroid gland is a rare disease. In the present study, the survival rate and characteristics were retrospectively analyzed in 22 patients with stage IE and IIE thyroid NHL treated with radiotherapy with or without combination chemotherapy. Seventeen NHL had histological evidence of lymphoma of mucosa-associated lymphoid tissue (MALT) type. The 5-year survival rate was 85% in all patients, with 100% and 63% respectively, for stage IE and stage IIE patients. The highly significant factor correlated with decreased determinate survival was concomitant stridor.

Adult↗

PubMed1996

Effect of varicocelectomy on sperm parameters and pregnancy rate in patients with subclinical varicocele: a randomized prospective controlled study.

PURPOSE: We assessed whether subclinical varicocele ligation improves fertility and/or semen parameters. MATERIALS AND METHODS: A total of 85 patients with a subclinical varicocele diagnosed by scrotal thermography presented with infertility. Patients were randomly assigned to groups 1 (high ligation of the internal spermatic vein) and 2 (followed without any treatment). At least 3 semen samples were obtained at study entry and 1 year later in both groups. RESULTS: The pregnancy rate in group 1 was 6.7% compared to 10% in group 2, and the difference was not statistically significant. Group 1 had significantly higher levels of sperm density and total motile sperm count at 1 year. There were no significant differences between groups 1 and 2 regarding change in seminal volume, sperm motility and abnormal sperm morphology. CONCLUSIONS: Subclinical varicocelectomy has some effect on spermatogenesis but no beneficial effect on pregnancy rate.

Adult↗

PubMed1995

Fluorodeoxyglucose positron emission tomography in pancreatic cancer: an unsolved problem.

The aim of this study was to examine the significance and problems of 2-[fluorine-18]-2-deoxy-d-glucose (FDG) positron emission tomography (PET) in diagnosing pancreatic cancer and mass-forming pancreatitis (MFP). PET, X-ray computed tomography (CT) and magnetic resonance (MR) imaging were performed in 15 patients with pancreatic cancer and nine patients with MFP. The areas of the PET scan were determined according to the markers drawn on the patients at CT or MR imaging. Regions of interests (ROIs) were placed by reference to the CT or MR images corresponding to the PET images. Tissue metabolism was evaluated by the differential absorption ratio (DAR) at 50 min after intravenous injection of FDG [DAR = tissue tracer concentration/(injected dose/body weight). The DAR value differed significantly in pancreatic cancer (mean +/- SD, 4.64 +/- 1.94) and MFP (mean +/- SD, 2.84 +/- 2.22) (P < 0.05). In one false-negative case (mucinous adenocarcinoma), the tumour contained a small number of malignant cells. In one false-positive case, lymphocytes accumulated densely in the mass in the pancreatic head. Further studies are necessary to investigate the histopathological characteristics (especially the cellularity) and other factors affecting the FDG DAR on PET images.

Adenocarcinoma↗

PubMed1995

Development of distributed image database combined with clinical information in hospital information system.

We have developed a distributed image database system composed of the data in our medium-scale PACS that provides diagnostic-quality images and the data in our HIS. INFORMIX software was used to construct the distributed relational database. The data in HIS were retrieved using several programs written in COBOL. Image data in PACS were retrieved using ACR-NEMA protocols. The data retrieved from the HIS database involved medication, disease entities, laboratory test results, etc. Therefore, the image data on a given patient can be retrieved by specifying the name of the disease in our database system. Our method offers a practical one to make a global database system to maintain the integrity of the data in the HIS and the PACS. The combination of image data and disease made it quite easy to make a sample database for developing a computer-aided diagnostic system.

Computer Communication Networks↗

PubMed1995

Diagnostic usefulness of chest computed radiography--film versus cathode-ray tube images.

Seventy-one plain chest images obtained by computed radiography (CR) with an imaging plate were interpreted on film and two kinds of cathode-ray tube (CRT) monitors installed separately at two facilities (1,024 x 1,536 pixels, 8 bits, and 1,024 x 1,280 pixels, 10 bits) by 20 radiologists and four chest internists. The clinical categories of these 71 cases included pulmonary nodules and interstitial abnormalities. Image reading sessions were held over a total of 4 days, ie, 2 days and then another 2 days, 3 weeks later. Twenty-four observers formed four groups with six members each. Two groups read either films or CRT images at one of the two facilities. In the second experiment, 26 of 71 images were compressed at 10:1, 19 of 71 were compressed at 20:1, and 26 were not compressed. Analyses of the areas under the receiver-operating characteristic curves showed no significant differences in detection of pulmonary abnormalities between film and CRT. In detecting interstitial pulmonary abnormalities, film was more sensitive than CRT monitor. There were no significant differences in observers' performances between the two different kinds of CRT workstation. Subjective evaluation of image quality showed that images irreversibly compressed to the ratios of 10:1 and 20:1 were inferior to original images. Although further considerations are needed with regard to spatial resolution requirements, image processing, and image compression, the utilization of CR CRT image as a substitute for CR film image will be possible.

Data Display↗

PubMed1995

The gene encoding the 5-HT1A receptor is intact in mood disorders.

We studied the 5-HT1A receptor gene in 50 mood disorders and 50 normal volunteers. The 5-HT1A receptor gene was amplified by polymerase chain reaction and sequenced by the dideoxy method. The sequence of the 5-HT1A receptor encodes a protein of 422 amino acids, that is, one amino acid longer than the reported sequence (Kobilka et al. 1987). The DNA sequence at positions 454 to 459 is CGC GCC GCT, not CCG CGT, and the amino acids sequence at these positions is changing from proline arginine to arginine alanine alanine. These differences, however, were observed in both mood disorders and controls. One silent polymorphism, CTG to GTA at position 294, was found. These results suggest that the 5-HT1A receptor gene is intact in mood disorders.

Adult↗

PubMed1995

Brain distribution characteristics of xanthine derivatives and relation to their locomotor activity in mice.

The relationship between the brain distribution and motor activity in mice of the xanthines, theophylline, enprofylline, 1-methyl-3-propylxanthine (MPX) and oxpentifylline was investigated. Their plasma protein binding and hydrophobicity were also examined. When these xanthines were administered orally, enprofylline and oxpentifylline had no effect on motor activity. While theophylline increased motor activity over 10 mg kg-1, MPX caused a decrease in such activity over 10 mg kg-1. The protein-binding behaviour varied among these xanthines and was closely related to their hydrophobicity, which is represented as a logarithmic partition coefficient (log PC). MPX had the highest hydrophobicity, while oxpentifylline had the lowest. Brain distribution characteristics varied among these xanthines, with the rank order of their brain penetration ratio, calculated as the ratio of brain to unbound plasma concentrations, being theophylline > oxpentifylline > MPX > enprofylline. The inhibition constants (Ki) for adenosine A1 receptors and cyclic 3',5'-adenosine monophosphate (cAMP)-phosphodiesterase (PDE) of these xanthines were 44.6 and 134, > 1000 and 112, 26.4 and 49, and > 1000 and 111 microM for theophylline, enprofylline, MPX, and oxpentifylline, respectively. These findings suggest that the lack of effects of enprofylline and oxpentifylline on motor activity is probably due to their low brain penetration ratio or low adenosine A1 affinity in comparison with theophylline. The decrease in the motor activity by MPX may be, in part, mediated by cAMP or adenosine.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1995

[CT findings of mass-forming pancreatitis: correlation with histopathologic findings].

We attempted to analyse the computed tomographic (CT) characteristics of mass-forming pancreatitis. Thirty inflammatory masses were studied using the combined method of dynamic CT (Dy-CT) and high dose enhancement CT (HD-CT) with a thin-section scan. From the correlation between the CT enhancement effect and the histopathologic changes, injury of the glandular element and proliferation of fibrous tissue were more prominent in inflammatory masses showing a different enhancement effect from the surrounding pancreatic parenchyma. In addition to these changes, constriction of the intrapancreatic artery caused a poor enhancement effect on Dy-CT, whereas marked round cell infiltration with lymphoid follicle formation increased the enhancement effect on HD-CT. This combined CT method is valuable for the diagnosis of mass-forming pancreatitis and adequately reflects its histopathologic condition.

Adult↗

PubMed1995

[CT findings of pancreatic carcinoma: evaluation with the combined method of early enhancement CT and high dose enhancement CT].

Computed tomographic (CT) findings of pancreatic ductal adenocarcinoma were studied with the combined method of early enhancement CT and high dose enhancement CT in 72 carcinomas. Common Findings were change in pancreatic contour, abnormal attenuation in a tumor and dilatation of the main pancreatic duct. The incidence of abnormal attenuation and dilatation of the main pancreatic duct and bile duct was constant regardless of tumor size. The finding of hypoattenuation at early enhancement CT was most useful for demonstrating a carcinoma. However, this finding was negative in ten cases, five of which showed inhomogenous hyperattenuation at high dose enhancement CT. The detection of change in pancreatic contour and dilatation of the main pancreatic duct was most frequent at high dose enhancement CT. The finding of change in pancreatic contour and/or abnormal attenuation in a tumor could be detected in 47 cases at plain CT, 66 at early enhancement CT and 65 at high dose enhancement CT. Since the four cases in which neither finding was detected by any CT method showed dilatated main pancreatic duct, there was no case without abnormal CT finding. This combined CT method will be a reliable diagnostic technique in the imaging of pancreatic carcinoma.

Adult↗

PubMed1995

[Optimal concentration of contrast medium in helical CT of the thorax].

In 99 examinations of 89 patients, we took CT images of the chest after administering one of three concentrations of contrast medium (iohexol 140 mgI/ml, 240 mgI/ml, 300 mgI/ml) to determine the optimal iodo-concentration for intravenous contrast enhancement in spiral CT. Attenuation values of the superior vena cava, ascending aorta, descending aorta, and pulmonary artery were measured to evaluate the degree of contrast enhancement. Five radiologists judged the image quality by scoring factors such as vascular opacification, delineation of the lung and chest wall, detectability of calcification, lymphadenopathy and pulmonary nodules, and the presence of artifacts. The relationships between the iodo-concentration and the scores were analyzed statistically. The higher the iodo-concentration of the contrast medium administered, the stronger the vascular structures were opacified. There was also a concurrent improvement in the detection of lymphadenopathy. However, artifacts appeared on the administration route as a result of the high-concentration contrast medium, and the image quality was degraded. Among the three groups, iohexol 240 mgI/ml exhibited the best performance, namely, good image quality, so that a high degree of contrast enhancement of the vasculature was obtained with few artifacts due to the contrast medium. However, we believe that iohexol 140 mgI/ml presents no significant problems in routine studies.

Adult↗

PubMed1995

[Evaluation of sleep apnea syndrome (SAS) with low field MR fluoroscopy].

Eight cases of clinically diagnosed sleep apnea syndrome (SAS) and two normal volunteers were studied with low field MR fluoroscopy in order to monitor the waking and sleeping status of the upper airway. MR fluoroscopy revealed that only the sleeping patients showed occlusions of the upper airway. This technique provided us with useful information about the level, frequency and duration of occlusion in each case. Four of the eight patients demonstrated simple retropalatal occlusion, whereas the other four demonstrated mixed retropalatal and retropalato-retroglossal occlusion. Thus long-time monitoring, which is only possible with MR fluoroscopy, is needed to appreciate the complex nature of the disease. In addition, the comfortable surroundings and low noise level provided by the low field enabled physiological study to be performed without any tranquilizers in most of the patients, which is again only possible with MR fluoroscopy. MR fluoroscopy may become a tool of great clinical value, providing much important information for disease evaluation and treatment selection.

Adult↗

PubMed1995

[High resolution MR imaging of the inner ear apparatus using 3D-Fast spin echo sequence].

To evaluate the efficacy of high resolution MR imaging of the inner ear with 3D-Fast spin echo sequence, one volunteer and 12 patients were imaged with a 1.5 T MR scanner. High resolution T2-weighted images were obtained with a head coil in 13 minutes, and the voxel size was 0.39mm x 0.45mm x 1.2mm in most subjects. Original images and maximum intensity projection (MIP) images of the inner ear were evaluated. On original images, the endolymphatic duct was visualized in 72% of subjects, the cochlear aqueduct in 96%, three branches of the cranial nerves in the internal auditory canal in 100%, and flow void of the vessel in the cerebellopontine angle in 100%. On MIP images, more than two cochlear turns were visualized in 92% of subjects, three semicircular canals in 100%, and the anterior and posterior ampulla in 100%. MR imaging of the inner ear with 3D-Fast Spin Echo sequence provides a variety of useful information regarding the anatomy around the inner ear.

Ear, Inner↗

PubMed1994

Comparison of radiosensitizing effect of KU-2285 and SR-2508 at low drug concentrations and doses.

PURPOSE: Since the radiosensitizing effect of KU-2285 at relatively low dose levels is not known, we investigated its efficacy at such low concentrations or doses achievable in humans with oral administration of 0.3-1.0 g/m2. METHODS AND MATERIALS: KU-2285 was tested in comparison with SR-2508 at low concentrations (0.05-0.25 mM) in vitro by the cytokinesis-block micronucleus assay and by the colony formation assay, and at low drug doses (12.5-50 mg/kg) in vivo by the in vivo-in vitro assay and by the growth delay assay using SCC VII tumors in C3H/He mice. RESULTS: In the cytokinesis-block micronucleus assay, the sensitizer enhancement ratio (SER) for KU-2285 and SR-2508 was 1.43 and 1.17 at 0.05 mM, 1.75 and 1.27 at 0.10 mM, and 2.14 and 1.69 at 0.25 mM, respectively. In the colony formation assay, the SER for KU-2285 was also greater than that for SR-2508. In the in vivo-in vitro assay, the SER for KU-2285 and SR-2508 was 1.11 and 1.04 at 12.5 mg/kg, 1.21 and 1.04 at 25 mg/kg, and 1.26 and 1.18 at 50 mg/kg, respectively. In the growth delay assay at 50 mg/kg, no tumor regrowth was observed in four of the 18 mice treated with KU-2285 + 25 Gy, although the growth delay time for the remaining mice was similar to that for SR-2508 + 25 Gy. CONCLUSION: KU-2285 was more effective than SR-2508 both at low drug concentrations in vitro and at low drug doses in vivo. These promising findings suggest the potential superiority of KU-2285 over SR-2508 as a radiosensitizer for clinical use.

Animals↗

PubMed1994

MR imaging in patients with strabismus.

The patients with strabismus, including 8 with superior oblique paresis, 1 with inferior rectus paresis, and 1 with congenital constant exotropia, were examined with MR imaging at 1.5 tesla (T) or 0.5T with a surface coil. Abnormal findings of extraocular muscles were identified in 8 of the 10 patients and most of them were consistent with the clinical findings. Deviation of the optic nerves was noted in 5 patients. Coronal short repetition time (RT) and echo time (ET) images were used to measure the concerned extraocular muscles and the optic nerves. The differences in diameters between the concerned extraocular muscles of both the diseased and normal eyes were calculated. MR imaging is considered to be advantageous and can be favorably used to observe and measure the extraocular muscles and other intraorbital structures in patients with strabismus.

Adult↗

PubMed1994

Fundamental and clinical evaluation of chest computed tomography imaging in detectability of pulmonary nodule.

Fundamental and clinical evaluation of chest CT imaging in detectability of pulmonary nodules was carried out in comparison with projection chest radiography including conventional screen-film system, advanced multiple beam equalization radiography (AMBER System), and computed radiography with imaging plate (CR). Detectability of simulated nodules in the fundamental study and of metastatic pulmonary nodules in ten patients in the clinical study was analysed by five radiologists. CT found the greatest number of nodules and also showed the highest sensitivity in detecting nodules of less than 5 mm in both the fundamental and clinical studies. The ability of computed tomography to visualize small pulmonary nodules may make it a possible substitute for chest radiography as the primary mass screening method, and as the examination method for small metastatic nodules (less than 5 mm) in patients with extrathoracic malignancy. There was no significant difference between conventional radiography, AMBER, and CR in the number of detected nodules.

Humans↗

PubMed1994

Intraarterial infusion of autologous lymphocytes for the treatment of refractory lymphoedema. Preliminary report.

OBJECTIVE: To evaluate the results of the treatment of lymphoedema by intra-arterial infusion of autologous lymphocytes. DESIGN: Open study. SETTING: University Hospital. SUBJECTS: 13 patients with refractory lymphoedema. INTERVENTIONS: Lymphocytes were separated from the patient's own blood using a blood cell separator; about 100 cc of lymphocyte dominant blood separated from this blood was immediately infused into the proximal artery of the affected limb. Infusion was practiced once a week, and repeated 4 to 6 times. MAIN OUTCOME MEASURES: Change in size of the affected limb (defined as the difference between the affected limb and the normal limb after treatment), and softening of the edema (measured with a tension gauge). RESULTS: In all 13 patients there was softening of the affected hard limb followed by a reduction in the size of the limb (mean 64%), and the ache and sensation of heat in the limb lessened. The reduction in size was maintained in 9 of the 13 patients for three months, despite returning to their normal activities. CONCLUSION: Intra-arterial infusion of autologous lymphocytes is a promising treatment for refractory lymphoedema.

Adolescent↗

PubMed1993

[Kinetics of flomoxef sodium monitored with in vivo 19F NMR spectroscopy].

The potential usefulness of in vivo 19F NMR spectroscopy for the monitoring of flomoxef sodium (FMOX) kinetics was evaluated. In the experimental study using phantom the minimum concentration of FMOX of which signals could be monitored with 19F NMR spectroscopy was 16 micrograms/ml. In patients with intravenous bolus injection and drip infusion of FMOX (2 g/100 ml), signals from normal heart, liver, and kidney were clearly monitored with 19F NMR spectroscopy. In normal lung any signal was not detected, but in a lung with a cancer associated massive atelectasis the monitoring of signals was possible with 19F NMR spectroscopy in both intravenous and intraarterial injections. Monitoring of FMOX kinetics with in vivo 19F NMR spectroscopy will be useful in clinical applications.

Cephalosporins↗