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Biomedical subjects

Y Inagaki

Publications and source records attributed to Y Inagaki.

At least 307 records · Page 17Linked to original sources
PubMed1987

[Diagnosis of atrial septal defect using magnetic resonance imaging].

We studied the morphological features of defects of the interatrial septum using magnetic resonance imaging (MRI) to determine the sizes of defects and other abnormalities. MR images were obtained in 28 patients with atrial septal defect, including five cases with complicated anomalies (two with Ebstein's anomaly, one pentalogy of Fallot, and one anomalous pulmonary vein connection and azygos continuation). Images were also obtained in the control subjects including seven normal volunteers and 142 patients with various acquired heart diseases. The diagnosis of atrial septal defect was established by cardiac catheterization, angiography and two-dimensional echocardiography prior to the MRI studies, and in 14 patients, the diagnosis was confirmed by surgery. The MRI unit had a superconducting magnet and operated at 0.25 or 0.50 Tesla. A spin echo pulse sequence was used with an echo time of 40 or 60 msec. At the beginning of this study, non-gated MRI images were obtained in the 28 controls and in three patients with atrial septal defect. Nongated MRI could not image the anatomical structure of the interatrial septa of 12 of the 28 controls, or any of the three patients with atrial septal defect. Nongated MRI was, therefore, inadequate for visualizing cardiac anatomy. Gated MRI images were obtained in 141 controls and in 25 patients with atrial septal defect. Gated MRI revealed the interatrial septum, interventricular septum, atrioventricular septum, mitral valve, tricuspid valve and other intracardiac structures in most subjects. In 17 control subjects (12%), however, there was a very faint signal from the central portion of the interatrial septum. In these instances, there was a gradual fading of the signal of the interatrial septum, so that they could be distinguished from the atrial septal defect. The sudden disappearance of the signal from the interatrial septum was observed by gated MRI in all 25 patients with atrial septal defect. The sizes of the defects by MRI coincided with the findings at surgery in all 14 patients. MRI showed right atrial dilatation, right ventricular hypertrophy and dilatation, and pulmonary artery dilatation in most of the patients having atrial septal defect. Complex anomalies associated with atrial septal defect were also clearly shown by MRI, such as displacement of the tricuspid leaflets in two patients with Ebstein's anomaly, and anomalous pulmonary venous connection and persistent left superior vena cava in one patient. These results indicated that gated MRI is a valuable noninvasive method of diagnosing atrial septal defect and complicating anomalies.

Adolescent↗
PubMed1987

[Problems related to tracer concentration and wall thickness: pitfalls in positron CT diagnosis].

Positron emission computed tomography (PET) is regarded an excellent technique for quantitative measurements. However, its accuracy is related to the spatial resolution of the system. The relation between myocardial wall thicknesses as measured by X-ray CT or MRI and the radioactivity as measured using PET was studied in 37 patients. 1. In patients with transmural infarction, the infarcted myocardium was imaged as a region of low radioactivity. However, the myocardium usually exhibited wall thinning, so that partial volume effects must be taken into account in evaluating the radioactivity. 2. In the infarcted regions, the regions of the low radioactivity tended to be larger than those of wall thinning. 3. There were cases with the regional low radioactivity without wall thinning in myocardial infarction and in hypertrophic cardiomyopathy. Because patients with myocardial infarction frequently had regional wall thinning, it seems necessary to correct partial volume effects for the infarcted regions which differ from the normal. It was concluded that, to estimate regional myocardial blood flow or metabolism using PET, it is necessary to supplement another morphological diagnostic method to evaluate myocardial wall thickness.

Ammonia↗
PubMed1987

[Dynamic function studies with positron computed tomography: measurements of regional myocardial blood flow in hypertrophic cardiomyopathy].

A major attribute of positron computed tomography (PCT) is its ability to dynamically measure physiologic processes of the heart. However, quantitative data acquisition and analysis are limited by three major problems: bidirectional activity-cross contamination between the myocardium and the blood, the partial volume effect, and the lower temporal resolution of PCT devices. In the present study, we performed serial six-second PCT scans (fast dynamic study) using 13N-ammonia, and evaluated measurements of regional myocardial blood flow. Six patients with hypertrophic cardiomyopathy (HCM) and five normal subjects were observed. 13N ammonia (4.2-13.0 mCi) was intravenously injected as a bolus, and serial six-second PCT scans were initiated at the times of the tracer injections. The results were as follows: 1. Initial passage of the tracer through the right and left sides of the heart were observed with serial six-second images. 2. In patients with HCM, Myocardial 13N activity was determined by assigning a region of interest (ROI) over the myocardium of greater than 25 mm wall thickness as measured by contrast enhanced CT. In these ROIs, corrections for the partial volume effect and spillover of radioactivity from the blood were not necessary. Arterial 13N activity was determined noninvasively by assigning a ROI over the left atrium. 3. The temporal relationships between the arterial input function and myocardial tracer concentrations were demonstrated. Arterial 13N activity was greatest in the second or third frame, and it rapidly declined thereafter. Myocardial 13N activity increased rapidly, reaching a plateau from the sixth to the ninth frame.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

New micro-glass-tube leukocyte adherence inhibition assay assessing cell adherence of mononuclear cell subpopulations defined by monoclonal antibodies.

A new micro-glass-tube leukocyte adherence inhibition (LAI) assay which is appropriate for detecting delayed type hypersensitivity in vitro has been developed for human leukocytes. Enumeration of adherent cells is replaced by a cellular radioimmunoassay determining antibody binding of the monoclonal reagents, OKT4, OKT8 and OKM1, to glass-adherent cells, fixed by glutaraldehyde or formaldehyde. An LAI reactivity to purified protein derivative of tuberculin (PPD) was detectable in donors giving a positive PPD skin test with OKT4 reagent, but not with the other two reagents.

Antibodies, Monoclonal↗
PubMed1986

The rapid change of corneal curvature in the neonatal period and infancy.

We measured the radii of corneal curvature of premature and mature newborns, using a rearranged automated keratometer and carried out a consecutive study in 18 of the newborns. The mean keratometry value in diopters (D) for seven premature babies was 49.50 D; that for 11 mature babies 47.00 D. The change of corneal curvature over time was observed in eight newborns (16 eyes). It showed rapid change from 49.01 to 45.98 D during 2 to 4 weeks of life and became very slow after 8 weeks of life (44.60 D). It would appear that the change of corneal curvature does not keep pace with the increase of axial length after 12 weeks of life, and constant ocular refractive status probably requires substantial changes in lenticular power.

Aging↗
PubMed1986

Fast dynamic study in cardiac positron CT using 13N-ammonia in man.

Fast dynamic studies with positron computed tomography (PCT) of the heart have been relatively few because of the technical limitations of prevalently used PCT devices. In the present study, we used a high-sensitivity, whole-body multislice PCT device (POSITOLOGICA-II) and performed serial 6-s PCT scans after the intravenous bolus injection of 13N-ammonia in 15 cardiac patients and 5 normal subjects. On the first image (0-6 s), 13N activity was primarily in the right atrium and ventricle. On the third image (12-18 s), it was primarily in the left atrium and ventricle. These blood-pool images permit evaluation of size and configuration of ventricles and atria in cardiac patients and normal subjects. Clearance of 13N activity in the blood pools and lungs occurred primarily during the 1st min. Thereafter, the myocardial images were delineated. In patients with heart failure, delayed clearance of the tracer from the blood pools and lungs was observed. The results indicate that initial passage of the tracer through the heart can be observed with the use of fast dynamic PCT.

Adult↗
PubMed1986

Clinical evaluation of bisoprolol in patients with hypertension: interim report.

The antihypertensive effect and possible adverse effects of bisoprolol were assessed in 96 Japanese patients with mild to moderate hypertension. After a 2- to 4-week placebo period, bisoprolol was administered to 68 outpatients at a daily dose of 5 mg to 20 mg for 6 to 8 weeks, and to 28 inpatients with the same dose range up to a maximum of 4 weeks. For outpatients, blood pressure and heart rate were recorded every 2 weeks, while for inpatients, in addition to daily measurements, the effect of bisoprolol on diurnal variation of blood pressure was also studied. Bisoprolol lowered blood pressure and heart rate significantly in both groups of patients. The most common adverse effect was bradycardia. It is expected that bisoprolol will be a very effective and useful antihypertensive drug.

Adrenergic beta-Antagonists↗
PubMed1986

[Stewart-Bluefarb syndrome (kaposiform arteriovenous fistula with bone changes)].

In a 14-year-old female patient with arteriovenous shunts (Stewart-Bluefarb syndrome), fist-sized cutaneous swelling, venous dilatation, blue-brown pigmentation and painful subcutaneous fingertip-sized nodules were noted on the right lower thigh. In addition to an arteriovenous malformation, bone hypertrophy, bone atrophy and after bone defects were observed in the involved area on X-ray examination. Histological examination revealed increased vascularity and vascular cavernous structures with endothelial swelling and extravasation of erythrocytes, but no malignant changes.

Adolescent↗
PubMed1986

[Diagnosis of mitral valve prolapse by X-ray CT and MRI].

To evaluate the usefulness of enhanced X-ray CT and gating magnetic resonance imaging (MRI) for diagnosing mitral valve prolapse, three patients with this abnormality and several controls were examined by these two methods. The mitral valve was not recognized by X-ray CT except a few cases with thickened mitral valve. However, MRI could demonstrate clearly the mitral leaflets and annulus in many subjects. In transverse MR imaging of the subjects without valvular disease, the closed mitral valve showed V-shaped appearance in the left ventricle during systole. In a patient with marked mitral valve prolapse, MRI revealed buckling of the posterior mitral leaflet into the left atrium, and in two other patients with mild mitral valve prolapse, MRI demonstrated displacement of coaptation of the anterior leaflet toward the left atrium. These results suggest MRI is a useful method for diagnosing mitral valve prolapse.

Echocardiography↗