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Biomedical subjects

J Taki

Publications and source records attributed to J Taki.

At least 181 records · Page 10Linked to original sources
PubMed1989

[Evaluation of ischemic heart disease by thallium-201 washout-rate map using SPECT].

In thallium-201 myocardial perfusion scintigraphy, washout rate (WR) has been used for the evaluation of the severity of ischemic heart disease (IHD). The WR was calculated from the polar map (Bull's-eye display) of myocardial perfusion using SPECT. To analyze the abnormality of WR map, we computed the extent and severity scores of WR. Applications of two types of standards, absolute and relative standards from control group (n = 16), were compared. The multiple regression analysis showed that the global WR was a function of the severity of coronary artery stenosis and exercise level, i.e. WR (%) = -2.38 X (number of stenotic artery) + 0.093 X (rate-pressure product/100) + 19.7 (n = 62, r = 0.63). Thus in evaluating the severity of IHD by absolute WR, the correction of WR was necessary according to the exercise level. Whereas, to evaluate the score of WR abnormality in polar map, the relative standard separated each group with different number of stenotic artery better than absolute standard did. In conclusion, calculation of WR score from relative standard is recommended for the analysis of polar WR map, although absolute global WR is useful for the evaluation of severity of coronary artery disease.

Coronary Disease↗
PubMed1989

[Separate evaluation of beta-methyl fatty acid uptake and perfusion in rat myocardium].

The kinetics and distribution of I-125 beta-methyl iodophenyl pentadecanoic acid (BMIPP) in rat's heart were studied for separate evaluation of perfusion and metabolism. Tl-201 and BMIPP were simultaneously injected. The experimental groups consisted of control (C), glucose (G) and sodium lactate loaded group (L). In C, myocardial uptake at 5 minutes after BMIPP injection was 3.60% ID/g and remained constant up to 60 minutes. The myocardium/lung ratio (2.44) and the myocardium/muscle ratio (4.55) of BMIPP were almost equal to those of Tl-201. But myocardium/liver ratio was low (1.31). In G, myocardial uptake of BMIPP (1.94 +/- 0.36% ID/g) and g-BMIPP/Tl (0.31 +/- 0.03) at 15 minutes after injection were significantly decreased (p less than 0.001) than those of C (3.16 +/- 0.18% ID/g and 0.48 +/- 0.05). In L. myocardial perfusion was decreased and g-BMIPP/Tl (0.73 +/- 0.14) was significantly higher (p less than 0.01) than those of C. Coefficient of variance of the density within a myocardium, and the ratio of inner to outer layer of myocardium (I/O ratio) were calculated from autoradiogram by videodensitometry. The myocardial distribution of BMIPP was more inhomogeneous, and the I/O ratio was lower than that of Tl-201, although these were not specific for metabolic interventions. In conclusion BMIPP is suitable for SPECT imaging and dual nuclide imaging by BMIPP and Tl-201 will provide informations about myocardial fatty acid metabolism and perfusion.

Animals↗
PubMed1988

Serial assessment of left ventricular function following coronary bypass surgery by radionuclide angiocardiography.

The serial change in left ventricular function was investigated by radionuclide angiocardiography in 25 patients undergoing coronary artery bypass grafting (CABG). Multiple gated equilibrium blood pool imaging was performed at rest before, and at 1, 2 and 4 weeks after the operation and also during exercise on a supine bicycle ergometer before and 4 weeks after surgery. Global ejection fraction at rest was unchanged after CABG while peak ejection rate increased significantly at 1 and 2 weeks (p less than 0.01 and p less than 0.05 respectively) after the operation. Peak filling rate at rest was generally unchanged after surgery but peak filling rate during the first third of diastole at rest decreased significantly at 1 and 2 weeks (p less than 0.01 and p less than 0.05). After CABG, the increases in ejection fraction and peak ejection rate with exercise were significantly greater than those values measured before surgery. The increases, due to exercise, in peak filling rate and peak filling rate during the first third of diastole were unchanged after the operation. Radionuclide angiocardiography affords a safe, noninvasive, and highly reproducible procedure for serially assessing ventricular function in patients undergoing CABG. Our study revealed early diastolic dysfunction within 2 weeks of surgery and that CABG abolished abnormalities in left ventricular function induced by exercise.

Aged↗
PubMed1986

Length-based Fourier analysis in the pre-excitation syndrome.

Length-based Fourier analysis (LFA) was applied to tomographic gated blood-pool study, and phase and percent-shortening diagrams were generated. In 22 patients with pre-excitation syndrome and ten control subjects, the most basal short-axis section was used for tomographic analysis. When the initial abnormal phase was considered as the location of accessory conduction pathway (ACP), correct diagnosis for the localization of ACP was given in 19 of 22 patients. In ten control subjects, no specific segments of initial phase were noted, although six patients had initial phase in the septal or paraseptal segments. The tomographic LFA was more effective for pinpointing the segment of the earliest phase than tomographic count-based phase analysis. The LFA provided objective three-dimensional information for contraction sequence. Because movements of ventricular edges are essential in tomography, the LFA was considered to be a reasonable approach for the analysis of tomographic gated blood-pool study.

Erythrocytes↗