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Biomedical subjects

Takeshi Hozumi

Publications and source records attributed to Takeshi Hozumi.

At least 19 recordsLinked to original sources
PubMed2006

Usefulness of automated quantitation of regional left ventricular wall motion by a novel method of two-dimensional echocardiographic tracking.

A novel 2-dimensional (2-D) echocardiographic tracking method enables the automated tracking of displacement between 2 points of interest in echocardiographic images. The purpose of this study was to evaluate whether this 2-D tracking method could be used to measure left ventricular (LV) wall thickness and percent systolic wall thickening (%WT) in parasternal short-axis views, in comparison with conventional manual measurement, and to determine whether this system can be used to quantitatively assess regional LV wall motion in echocardiography. In 24 subjects (12 with LV wall motion abnormalities), 6 segments in the short-axis images were assessed by this method. Two sample points at the endocardium and epicardium were tracked automatically during 1 cardiac cycle. Then, LV wall thickness and %WT were calculated. In 50 subjects (32 with LV wall motion abnormalities), average %WT as an average of all %WT in every degree of angle in each of the 6 segments was measured by this method, and the results were compared with the visual assessment of LV wall motion scores. There was excellent agreement between the 2-D tracking and manual methods for LV wall thickness (r = 0.99) and %WT (r = 0.97). The mean differences in LV wall thickness and %WT were 0.1 +/- 0.4 mm and 0 +/- 5.4%, respectively. Average %WT was significantly decreased in the regions of hypokinetic or akinetic wall motion compared with those of normal motion (18 +/- 4% and 4 +/- 4% vs 39 +/- 10%, p <0.001). In conclusion, this 2-D tracking method can be used for the noninvasive, automated quantitation of LV wall motion in 2-D echocardiography.

Echocardiography↗
PubMed2006

Three-dimensional geometry of the tricuspid annulus in healthy subjects and in patients with functional tricuspid regurgitation: a real-time, 3-dimensional echocardiographic study.

BACKGROUND: Most rings currently used for tricuspid valve annuloplasty are formed in a single plane, whereas the actual tricuspid annulus (TA) may have a nonplanar or 3-dimensional (3D) structure. The purpose of this study was therefore to investigate the 3D geometry of the TA in healthy subjects and in patients with functional tricuspid regurgitation (TR). METHODS AND RESULTS: This study consisted of 15 healthy subjects and 16 patients with functional TR who had real-time 3D echocardiography. With our customized software, 8 points along the TA were determined with the rotated plane around the axis at 45 degrees intervals. The TA was traced during a cardiac cycle. The distance between diagonals connecting 2 points was measured. The height was defined as the distance from the plane determined by least-squares regression analysis at all 8 points. Both the maximum (7.5+/-2.1 versus 5.6+/-1.0 cm2/m2) and minimum (5.7+/-1.3 versus 3.9+/-0.8 cm2/m2) TA areas in patients with TR were larger than those in healthy subjects (both P<0.01). Healthy subjects had a nonplanar-shaped TA with homogeneous contraction. The posteroseptal portion was the lowest toward the apex from the right atrium, and the anteroseptal portion was the highest. In patients with functional TR, the TA was dilated in the septal to lateral direction, resulting in a more circular shape than in healthy subjects. A similar 3D pattern was observed in patients with TR, but it was more planar than that in healthy subjects. CONCLUSIONS: Real-time 3D echocardiography showed a complicated 3D structure of the TA, which appeared to be different from the "saddle-shaped" mitral annulus, suggesting an annuloplasty for TR different from that for mitral regurgitation.

Adult↗
PubMed2006

Cut-off value of coronary flow velocity reserve by transthoracic Doppler echocardiography for the assessment of significant donor left anterior descending artery stenosis in patients with spontaneously visible collaterals.

We evaluated the influence of collateral circulation on a donor left anterior descending artery and an appropriate cut-off value of coronary flow velocity reserve for the diagnosis of significant donor left anterior descending artery stenosis. Measurement of coronary flow velocity reserve by transthoracic Doppler echocardiography provides noninvasive assessment of significant left anterior descending artery stenosis. The cut-off value of coronary flow velocity reserve for the diagnosis of significant donor left anterior descending artery stenosis has not been well studied. We retrospectively examined 64 patients who had no significant left anterior descending artery stenosis and who had other coronary artery stenosis. Seventeen patients had collaterals from the left anterior descending artery (group A) and 47 patients did not have collaterals (group B). We prospectively examined 23 consecutive patients who had collaterals from the left anterior descending artery to other coronary arteries. Eight patients had a significant donor left anterior descending artery stenosis. Coronary flow velocity reserve assessment was performed by transthoracic Doppler echocardiography in the 2 protocols. Coronary flow velocity at baseline in group A was significantly higher than that in group B. Coronary flow velocity reserve in group A was significantly lower than that in group B (2.6 +/- 0.8 vs 3.2 +/- 0.9, p < 0.05). Coronary flow velocity during hyperemia and coronary flow velocity reserve were significantly lower in patients with significant stenosis. A cut-off value of 2.0 of coronary flow velocity reserve had a sensitivity of 88% and a specificity of 93% for the diagnosis of significant donor left anterior descending artery stenosis. In conclusion, coronary flow velocity reserve of a donor left anterior descending artery was decreased by the presence of collaterals. However, a cut-off value < 2.0 was appropriate for the diagnosis of significant donor left anterior descending artery stenosis in a population that included patients with collaterals.

Blood Flow Velocity↗
PubMed2006

Detection of significant stenotic lesions in the left anterior descending coronary artery using adenosine triphosphate stress strain imaging: comparison with coronary flow velocity reserve measurement using transthoracic Doppler echocardiography.

To evaluate the usefulness of adenosine triphosphate stress strain imaging for detecting significant coronary artery disease in the left anterior descending coronary artery (LAD), 34 patients underwent coronary flow velocity reserve measurement in the distal LAD and adenosine triphosphate stress strain imaging simultaneously. Time to peak strain (TPS) was measured in the apical septal segment. TPS ratio was obtained as the ratio between TPS at adenosine triphosphate stress and at baseline. TPS ratio in 11 patients with LAD lesions was significantly greater than that in 23 patients without LAD lesions (1.24 +/- 0.17 vs 0.92 +/- 0.12, respectively, P < .0001). With a cut-off value greater than or equal to 1.1 for the TPS ratio and less than 2.0 for the coronary flow velocity reserve, diagnostic accuracy for the presence of significant LAD lesions were 88% and 82%, respectively. In conclusion, strain imaging can differentiate ischemic and nonischemic myocardium accurately comparable with coronary flow velocity reserve measurement.

Adenosine Triphosphate↗
PubMed2006

Coronary flow velocity reserve measurement in three major coronary arteries using transthoracic Doppler echocardiography.

BACKGROUND: Measurement of the coronary flow velocity reserve (CFVR) by transthoracic Doppler echocardiography (TTDE) has been reported to be useful for the noninvasive assessment of significant coronary artery stenosis or myocardial ischemia. The purpose of this study was to evaluate the value of this method in three major coronary arteries for detecting myocardial ischemia in the clinical setting. METHODS: We studied 89 consecutive patients who were referred to our outpatient clinic because of chest pain. We measured CFVR using TTDE in three major coronary arteries. We defined CFVR<2.0 in at least one vessel as being positive for myocardial ischemia. The accuracy of CFVR measurements for detecting myocardial ischemia was determined in comparison with exercise thallium-201 (Tl-201) single photon emission computed tomography (SPECT) as a reference standard. RESULTS: CFVR in at least one vessel was successfully measured in 87 of 89 patients (98%). The sensitivity and specificity of CFVR<2.0 in at least one coronary vessel, in any of the coronary territories, was 86% and 89%, respectively. In terms of assessing myocardial ischemia in each coronary artery territory, the agreement between CFVR<2.0 and Tl-201 SPECT for the left anterior descending coronary artery, the posterior descending coronary artery, and the left circumflex coronary artery territories was 95%, 81%, and 73%, respectively. CONCLUSION: Noninvasive CFVR measurement by TTDE may be useful for detecting myocardial ischemia, as well as for identifying ischemic territories in the clinical setting.

Adenosine Triphosphate↗
PubMed2006

Automated three-dimensional analysis of mitral annular dynamics in patients with myocardial infarction using automated mitral annular tracking method.

BACKGROUND: A newly developed automated mitral annular tracking method (AMAT) has recently become available and enables us to perform automated analysis of mitral annular dynamics. PURPOSE: To evaluate mitral annular dynamics using AMAT. METHODS: AMAT was performed using a Toshiba Aplio SSA-770 ultrasound system in 15 normal healthy volunteers (group N), 16 patients with anterior MI (group A), and 12 inferior MI (group B). The distance between an annular point at end-diastole and at end-systole (distance D) was automatically measured using AMAT at the basal portion of the anterior, lateral, posterior, inferior, and inferoseptal wall. The angle between the mitral annular plane at end-diastole and the direction of movement of each mitral annular point from end-diastole to end-systole (angle A) was also automatically measured at all five mitral annular points. The coefficients of variation (CV) of both distance D and of angle A were calculated as indices of asynchrony of mitral annular dynamics. RESULTS: CV of distance D in group A (22 +/- 9% (P < 0.01 vs group N)) and group B (22 +/- 10% (P < 0.01 vs group N)) were both significantly larger than in group N (13 +/- 4%). CV of angle A in group A (15 +/- 10% (P < 0.05 vs group N)) and group B (15 +/- 10% (P < 0.05 vs group N)) were also significantly larger than that in group N (8 +/- 3%). CONCLUSION: Automated analysis using AMAT showed that mitral annular dynamics of patients with MI were less symmetrical than in normal healthy volunteers.

Adult↗
PubMed2006

Acute hyperglycemia induced by oral glucose loading suppresses coronary microcirculation on transthoracic Doppler echocardiography in healthy young adults.

OBJECTIVES: We sought to evaluate the effect of acute hyperglycemia on coronary microcirculation by noninvasive measurement of coronary flow velocity reserve (CFVR) using transthoracic Doppler echocardiography (TTDE). RESEARCH DESIGN AND METHODS: Measurements of CFVR using TTDE and levels of plasma glucose and serum insulin and lipids were determined before and 1 hour after loading with oral glucose (75-g glucose) in 10 young healthy males (mean age, 30 +/- 2 years) or an artificial sweetener in five of the 10 subjects without coronary risk factors. RESULTS: In all subjects, the levels of plasma glucose and serum insulin significantly increased after glucose loading compared with baseline (5.1 +/- 0.6 vs 7.6 +/- 1.2 mM/l, 6 +/- 3 vs 49 +/- 13 microU/ml, respectively; P < 0.0001). CFVR was significantly decreased 1 hour after acute oral glucose loading (4.4 +/- 0.7-3.8 +/- 0.7, respectively; P < 0.01). There was no significant change in CFVR after loading with an artificial sweetener (4.4 +/- 0.6-4.4 +/- 0.5 cm/sec). CONCLUSIONS: TTDE revealed that acute hyperglycemia induced by oral glucose loading suppresses CFVR in healthy young male subjects. This result suggests that acute hyperglycemia may have adverse effects on coronary microcirculation.

Acute Disease↗
PubMed2006

[Estimation of myocardial ischemia by diastolic strain analysis in exercise stress echocardiography: comparison with exercise thallium-201 single photon emission computed tomography].

OBJECTIVES: The feasibility of detecting persistent regional left ventricular abnormal relaxation due to myocardial ischemia using strain echocardiography several minutes after exercise was investigated. METHODS: Consecutive 27 patients (mean age 65 +/- 9 years, 21 males, 6 females) with suspected coronary artery disease were enrolled. Strain echocardiographic images were acquired at the mid segments of the left ventricular wall before and 5 min after exercise in the apical long-axis, two-chamber and four-chamber views. Strain curves were obtained at each segment, and peak values of strain at the closure of aortic valve (A) and at one third of diastolic duration (B) were measured. Strain diastolic index (SDI) was calculated as (A - B)/A X 100%. The ratio of SDI before exercise to that after exercise was defined as the SDI ratio and compared with exercise thallium-201 single photon emission computed tomography (SPECT) as the reference standard to detect myocardial ischemia. RESULTS: A total of 162 segments were evaluated. Based on the results of exercise SPECT, 119 segments were classified as non-ischemic segments, and 43 as ischemic segments. Ischemic segments showed significant decreases in SDI before and after exercise, whereas non-ischemic segments showed no significant differences in SDI before and after exercise. SDI ratio was significantly decreased in ischemic segments, but not in non-ischemic segments. SDI ratio with a cut off value of 0.51 had a sensitivity of 91% and a specificity of 89% to detect myocardial ischemia in the receiver-operating characteristics. Conclusions. Strain echocardiography can provide quantitative assessment of myocardial ischemia by detecting post-ischemic regional left ventricular delayed relaxation even 5 min after exercise.

Aged↗
PubMed2005

Comparison of accurate measurement of left ventricular mass in patients with hypertrophied hearts by real-time three-dimensional echocardiography versus magnetic resonance imaging.

To evaluate whether left ventricular (LV) mass assessed by a new real-time, 3-dimensional echocardiographic (RT-3DE) system corresponds to cardiac magnetic resonance imaging (MRI) in patients with LV hypertrophy, RT-3DE and 2-dimensional echocardiography (2DE) were performed to calculate LV mass in 21 patients (mean age 54 +/- 15 years) who underwent MRI for the evaluation of LV hypertrophy. In 20 of 21 patients, adequate 3-dimensional data for LV mass analysis were obtained, and regression analysis showed that LV mass by RT-3DE correlated with that determined by MRI (r = 0.95, y = 28.9 + 0.85x) better than with that determined by 2DE (r = 0.70, y = 43.6 + 0.81x). RT-3DE allows the accurate measurement of LV mass in patients with hypertrophied hearts.

Echocardiography, Three-Dimensional↗
PubMed2005

Non-invasive assessment of myocardial ischaemia using new real-time three-dimensional dobutamine stress echocardiography: comparison with conventional two-dimensional methods.

AIMS: Although two-dimensional-dobutamine stress echocardiography (2D-DSE) is useful for the diagnosis of myocardial ischaemia, it requires the acquisition of multiple cross-sections at each stage. The introduction of new real-time three-dimensional echocardiography (RT3DE) offers rapid acquisition and 3D display of the entire left ventricle (LV). The purpose was to evaluate real-time three-dimensional-dobutamine stress echocardiography (RT3D-DSE) for the diagnosis of ischaemia using exercise (201)Tl single-photon emission computed tomography (SPECT) as the reference standard, in comparison with 2D-DSE. METHODS AND RESULTS: We performed DSE in 56 consecutive patients who had undergone SPECT because of suspected ischaemia. 3D images by RT3DE were acquired from the apical window after the acquisition of cross-sectional images at every stage of 2D-DSE. Wall motion analysis in RT3DE was performed from anatomical images by cropping the acquired full volume data sets. Mean scanning time for adequate image acquisition at peak stress by RT3D-DSE was shorter than that by 2D-DSE (29+/-4 vs. 68+/-6 s, P<0.0001). RT3DE provided adequate images at success rate of 92% at rest and 89% at peak stress, whereas two-dimensional echocardiography did at 94 and 90%, respectively. The sensitivity, specificity, and accuracy of RT3D-DSE for the detection of coronary artery disease are 86, 80, and 82%, respectively. Those of 2D-DSE are 86, 83, and 84%, respectively. There were no significant differences in the sensitivity, specificity, and accuracy between these two methods (P=1.000). CONCLUSION: RT3D-DSE offers rapid and simple acquisition of the entire LV wall motion and provides feasible and accurate assessment of myocardial ischaemia.

Aged↗
PubMed2005

A novel technique to detect total occlusion in the right coronary artery using retrograde flow by transthoracic Doppler echocardiography.

BACKGROUND: We hypothesized that detection of reverse flow in the distal right coronary artery (d-RCA) and the inferior septal branches (ISB) by transthoracic Doppler echocardiography (TTDE) would be useful for noninvasive diagnosis of the occluded right coronary artery (RCA). METHODS: Coronary angiography and TTDE were performed on 129 patients. Antegrade flows in the d-RCA and the ISB were defined as directions from the base to the apex in the posterior sulcus and from anterior to inferior in the inferior septum, respectively. Retrograde flow was defined as an inverse direction. RESULTS: Retrograde flow was obtained by TTDE in 14 patients (d-RCA:11, ISB:3) of 18 patients with occluded RCA. The sensitivity and the specificity for identification of occluded RCA were 100% and 97.8%, respectively. CONCLUSION: Detection of reverse flow in the d-RCA and the ISB using TTDE is a useful method for the noninvasive diagnosis of occluded RCA.

Aged↗
PubMed2005

Transthoracic Doppler echocardiographic assessment of coronary flow velocity pattern in patient with acute myocardial infarction implies progression of myocardial damage.

BACKGROUND: Coronary flow velocity (CFV) pattern with a rapid deceleration time of diastolic flow velocity and small average systolic peak velocity immediately after reperfusion implies poor wall-motion recovery in patients with acute myocardial infarction. Microvascular injury has been demonstrated to progress after coronary reperfusion. The purpose of this study was to assess whether CFV 1 day after reperfusion (day 1) may reflect accurately the degree of myocardial damage. METHODS: In the left anterior descending coronary artery in 29 patients with anterior acute myocardial infarction, CFV was measured immediately and 1 day after recanalization using transthoracic Doppler echocardiography, respectively. Regional wall motion was estimated as anterior wall-motion score index (AWMSI) by echocardiography before recanalization and 1 month after the onset of acute myocardial infarction. RESULTS: Although significant correlation was observed among deceleration time of diastolic flow velocity, average systolic peak velocity, and average peak velocity immediately after reperfusion and 1-month AWMSI (r = -0.62, P < .001; r = -0.61, P < .001; and r = -0.55, P < .01, respectively), much better correlation was demonstrated between those at day 1 and 1-month AWMSI (r = -0.72, P < .0001; r = -0.68, P < .0001; and r = -0.60, P < .001, respectively). Deceleration time of diastolic flow velocity, average systolic peak velocity, and average peak velocity in poor wall-motion recovery group (1-month AWMSI > 2.0, n = 14) were significantly smaller (P < .01, P < .05, and P < .05, respectively) at day 1 compared with those immediately after reperfusion. CONCLUSIONS: CFV pattern assessed by transthoracic Doppler echocardiography at day 1 provides the degree of myocardial damage much more accurately than that immediately after reperfusion. These results may suggest that myocardial damage progresses after reperfusion.

Blood Flow Velocity↗
PubMed2005

Freehand three-dimensional echocardiography with rotational scanning for measurements of left ventricular volume and ejection fraction in patients with coronary artery disease.

BACKGROUND: Measurement of left ventricular (LV) volumes and ejection fraction (EF) is important in managing patients with coronary artery disease (CAD). Introduction of free-hand three-dimensional echocardiography (3DE) system which is equipped with small magnetic tracking system and average rotational geometry for LV volumes may provide easy and accurate quantification of LV systolic function in CAD patients. PURPOSE: To evaluate the feasibility and accuracy of LV volumes and EF measurement by free-hand 3DE with rotational geometry in patients with CAD. METHODS AND RESULTS: The study subjects consisted of consecutive 25 patients with CAD who were scheduled for quantitative gated single-photon emission computed tomography (QGS). LV end-diastolic volume (EDV), end-systolic volume (ESV), and EF were determined by conventional two-dimensional echocardiography (2DE), 3DE, and QGS. Three-dimensional echocardiography data acquisition and analysis were possible in 22 of 25 subjects (feasibility 88%). In this 3DE system, image acquisition time was 2 minutes, and 5 minutes were needed for off-line analysis of LV volumes and EF. Correlations and the limits of agreement between 3DE and QGS (r = 0.97, 0.0 +/- 9.1 ml for EDV, r = 0.99, 0.0 +/- 5.0 ml for ESV, and r = 0.97, 0.5 +/- 3.3% for EF, respectively) were superior to those between 2DE and QGS (r = 0.85, 12.6 +/- 26.8 ml for EDV, r = 0.85, 9.7 +/- 26.1 ml for ESV, and r = 0.90, -1.3 +/- 6.9% for EF, respectively). Inter- and intra-observer variabilities of 3DE were smaller than that of 2DE (5% vs 10%, 5% vs 10% for EDV, 6% vs 13%, 5% vs 9% for ESV, and 4% vs 11%, 4% vs 6% for EF, respectively). CONCLUSION: Three-dimensional echocardiography using magnetic tracking system and average rotational geometry offered a feasible and accurate method for quantification of LV volumes and EF in patients with CAD.

Aged↗
PubMed2005

Impaired coronary circulation in patients with apical hypertrophic cardiomyopathy: noninvasive analysis by transthoracic Doppler echocardiography.

OBJECTIVES: We designed this study to examine the characteristics of coronary circulation in patients with apical hypertrophic cardiomyopathy (ApHCM) using noninvasive transthoracic Doppler echocardiography (TTDE). BACKGROUND: Recent advances in TTDE have allowed noninvasive assessment of coronary circulation by the measurement of coronary flow velocity (CFV) patterns and coronary flow velocity reserve (CFVR). However, there have been no previous studies evaluating coronary circulation in ApHCM. METHODS: We analyzed CFV and CFVR in the left anterior descending coronary artery (LAD), and apical wall thickness in the left ventricle, in 10 ApHCM subjects and 10 control subjects. Mean diastolic velocity (MDV) and time from the beginning of diastole to peak velocity (TPV), and CFVR, defined as a ratio of drug-induced hyperemic to basal MDV, were measured. RESULTS: At baseline, MDV was higher, and TPV was longer, in ApHCM subjects than in control subjects (29 +/- 5.7 versus 19 +/- 6.5 cm/sec; p < 0.01 and 5.2 +/- 1.0 versus 3.5 +/- 0.6 msec; p < 0.005, respectively). CFVR in ApHCM subjects was significantly lower than in control subjects (1.9 +/- 0.4 versus 3.1 +/- 0.8; p < 0.005). CFVR and basal MDV in ApHCM subjects showed significant correlations with apical/posterior wall thickness ratio [CFVR; r =-0.84, p < 0.01 and MDV; r = 0.74, p < 0.05, respectively]. CONCLUSION: Noninvasive coronary flow assessment by TTDE revealed an impaired coronary circulation with reduced CFVR, high MDV at baseline and prolonged TPV. These results suggest that these characteristics of coronary circulation may provide an additional index for the assessment of ApHCM.

Adenosine Triphosphate↗
PubMed2004

Effect of azithromycin therapy on coronary circulation in patients with coronary artery disease.

This study examined the effect of azithromycin therapy on the coronary microcirculation using measurement of coronary flow velocity reserve (CFVR) by transthoracic Doppler echocardiography in 35 patients with coronary artery disease. CFVR increased significantly after azithromycin therapy (3.0 +/- 0.7 vs 3.5 +/- 0.7, p <0.001). The changes in CFVR were negatively correlated with changes in high-sensitivity C-reactive protein levels in patients receiving azithromycin.

Aged↗
PubMed2004

Accuracy of measurement of left ventricular volume and ejection fraction by new real-time three-dimensional echocardiography in patients with wall motion abnormalities secondary to myocardial infarction.

Three-dimensional echocardiography is an ideal tool for the measurement of left ventricular (LV) volume because no geometric assumptions about LV shape are needed. The introduction of new real-time 3-dimensional echocardiography (RT3DE) has allowed rapid acquisition of a 3-dimensional dataset with good image quality. The purpose of this study was to examine the accuracy of RT3DE for the measurement of LV volume and ejection fraction in patients with wall motion abnormalities by using quantitative gated single-photon emission computed tomography (QGSPECT) as a reference standard. The study population consisted of 25 consecutive patients with wall motion abnormalities who underwent LV volume measurement by 2-dimensional echocardiography and by QGSPECT. LV volume and ejection fraction by RT3DE were measured offline by using the average rotation method. In 23 of 25 patients (92%), it was possible to measure 3-dimensional volume with RT3DE. RT3DE correlated well with QGSPECT in the measurement of end-diastolic volume and end-systolic volume (r = 0.97, mean difference 3.4 ml; r = 0.98, mean difference 2.0 ml, respectively), 2-dimensional echocardiography also correlated with QGSPECT but underestimated LV volume (r = 0.98, mean difference 21.1 ml; r = 0.98, mean difference 15.6 ml, respectively). Ejection fraction obtained by RT3DE had better agreement with that obtained by QGSPECT than that obtained by 2-dimensional echocardiography (r = 0.92, mean difference -0.2%; r = 0.89, mean difference -2.7%, respectively). RT3DE allows convenient and accurate estimation of LV volume and ejection fraction in patients with wall motion abnormalities.

Adult↗