Yoshiaki Inagaki

Bio: Yoshiaki Inagaki is an academic researcher from Chiba University. The author has contributed to research in topics: Essential hypertension & Blood pressure. The author has an hindex of 13, co-authored 84 publications receiving 628 citations. Previous affiliations of Yoshiaki Inagaki include University of Yamanashi.

Coronary artery calcification detected by CT: clinical significance and angiographic correlates.

Abstract: Cardiac computed tomography (CT) to detect coronary calcification was performed on 161 patients undergoing coronary angiography for proven or suspected coronary artery disease. Among 108 patients in whom coronary calcifications was identified, 90% had significant coronary stenosis angiographically (greater than 75% stenosis), and 80% of 121 patients with significant coronary stenosis showed calcification by CT. The relationship between the calcification site and the significance in stenosis of each vessel was determined. Calcification was present in 133 arteries among 205 stenotic coronary arteries (sensitivity = 65%) as compared with 59 of 439 entire arteries with normal coronary angiograms (specificity = 87%). In the younger age group the sensitivity of calcification for stenosis of each coronary artery was lower and the specificity and predictive value were generally higher than those in the elderly group. These results demonstrate that CT is a valuable procedure for detecting coronary arterial disease, since this examination is easy to conduct, noninvasive, and widely applicable for screening a large population.

High-energy phosphate metabolism of the myocardium in normal subjects and patients with various cardiomyopathies--the study using ECG gated MR spectroscopy with a localization technique.

Abstract: Nuclear magnetic resonance spectroscopy (MRS) is a new technique for the evaluation of myocardial metabolism. Recently, localized MRS has been clinically available to measure by a non-invasive method the relative concentrations of the high-energy phosphate metabolites in the myocardium. We performed ECG gated P-31 MRS using ISIS (image-selected in vivo spectoroscopy) in 15 normal volunteers, 12 patients with hypertrophic cardiomyopathy, 12 with left ventricular hypertrophy. 6 with dilated cardiomyopathy and 11 with specific heart muscle disease. Myocardial peak height ratios of PCr/γ-ATP, Pi/γ-ATP and PCr/Pi were measured. Myocardial P-31 MRS demonstrated a significant decrease in the ratio PCr/ATP in patients with hypertrophic cardiomyopathy and specific heart muscle disease as compared with normal subjects, indicating myocardial metabolic disturbance in these patients. The ratio of PCr/ATP in patients with dilated cardiomyopathy did not differ significantly from that of normal subjects. However, exercise MRS revealed a marked decrease of PCr peak in an asymptomatic patient with dilated cardiomyopathy, which may indicate a latent metabolic disturbance in the myocardium of dilated cardiomyopathy.

Coronary artery calcification: pathophysiology, epidemiology, imaging methods, and clinical implications. A statement for health professionals from the American Heart Association. Writing Group.

Abstract: Atherosclerotic calcification is an organized, regulated process similar to bone formation that occurs only when other aspects of atherosclerosis are also present. Nonhepatic Gla-containing proteins like osteocalcin, which are actively involved in the transport of calcium out of vessel walls, are suspected to have key roles in the pathogenesis of coronary calcification. Osteopontin and its mRNA, known to be involved in bone mineralization, have been identified in calcified atherosclerotic lesions. Calcified human atherosclerotic plaque also contains mRNA for bone morphogenetic protein-2a, a potent factor for osteoblastic differentiation, and cells that are capable of osteoblastic differentiation. These cells may be the ones from which vascular calcifying cells are derived. These and other recent findings indicate that calcification is an active process and not simply a passive precipitation of calcium phosphate crystals, as once thought. Although calcification is found more frequently in advanced lesions, it may also occur in small amounts in earlier lesions that appear in the second and third decades of life. Histopathological investigation has shown that plaques with microscopic evidence of mineralization are larger and associated with larger coronary arteries than are plaques or arteries without calcification. The relation of arterial calcification to the probability of plaque rupture is unknown. Although the amount of coronary calcium correlates with the amount of atherosclerosis in different individuals and to a lesser extent in segments of the coronary tree in the same individuals, it is not known if the quantity of calcification tracks the quantity of atherosclerosis over time in the same individuals. Further research is needed to better elucidate the relation of calcification to the pathogenesis of both atherosclerosis and plaque rupture. In vivo epidemiological evidence and postmortem studies show that the prevalence of coronary calcium deposits in a given decade of life is 10 to 100 times higher than the …

Electron Beam Computed Tomographic Coronary Calcium Scanning: A Review and Guidelines for Use in Asymptomatic Persons

Abstract: Coronary artery disease is the No. 1 cause of death in the developed world. Effective means of treatment such as drug therapy to lower cholesterol levels are available, but clinical application to patients at highest risk remains imprecise. Electron beam computed tomography (EBCT) has been suggested as a means to diagnose subclinical coronary disease and facilitate risk stratification, but no current interpretive consensus exists in clinical practice. We critically reviewed current, pertinent literature regarding EBCT coronary calcium scanning from a clinical perspective and, in particular, studies that evaluated it as a measure of atherosclerotic coronary disease. Additionally, we reviewed studies that quantified the EBCT "calcium score" in relationship to coronary heart disease events. The available data suggest that the EBCT calcium score can help identify persons at higher than anticipated risk of future coronary events: the greater the EBCT coronary calcium score, the greater the extent of atherosclerotic plaque disease. Based on the literature review, we offer EBCT interpretation guidelines as they relate to drug therapy and risk reduction in asymptomatic persons with borderline cholesterol levels. Considerable evidence shows that coronary calcium is specific for atherosclerotic plaque and that it can be sensitively detected and accurately quantified by using EBCT. The coronary calcium score can help guide initiation of clinical prevention programs as part of a risk stratification and management scheme aimed at improving outcomes in patients determined to be at highest risk of coronary disease for their respective age and gender.