PubMed Health⌕ Search

Biomedical subjects

H Masugata

Publications and source records attributed to H Masugata.

At least 19 recordsLinked to original sources
PubMed2001

Comparison of real-time and intermittent triggered myocardial contrast echocardiography for quantification of coronary stenosis severity and transmural perfusion gradient.

BACKGROUND: Both intermittent triggered and real-time myocardial contrast echocardiography (MCE) have been proposed to detect impaired myocardial perfusion. We compared the ability of these 2 methods to quantify altered myocardial blood flow (MBF) and transmural distribution of MBF produced by graded coronary stenoses. METHODS AND RESULTS: In 8 open-chest dogs, we created 4 graded left anterior descending coronary artery (LAD) stenoses: 3 levels of reduced adenosine hyperemia (non-flow-limiting at rest) and 1 grade of flow-limiting at rest. Real-time MCE was performed with SonoVue infusion using low-energy power pulse inversion (ATL) imaging, whereas ECG-gated intermittent triggered imaging used high energy at pulsing intervals from 1:1 to 1:10. LAD signal intensity (SI) was plotted versus time by real-time MCE and versus pulsing intervals by triggered MCE and was fitted to a 1-exponential function to obtain plateau SI (A) and the rate of SI rise (b). Visual detection of decreased opacification was equivalent by triggered and real-time MCE. Fluorescent microsphere-derived MBF ratio in LAD/left circumflex artery beds demonstrated close correlation with both real-time imaging (b, r=0.79; Axb, r=0.81) and triggered imaging (b, r=0.78; Axb, r=0.80). The endocardial/epicardial ratio of MBF in the LAD bed demonstrated closer correlation with the endocardial/epicardial ratios of b (r=0.71) and Axb (r=0.67) obtained by real-time than triggered imaging (b, r=0.42; Axb, r=0.52). CONCLUSIONS: Real-time and triggered MCE are equivalent in their ability to identify coronary stenosis and quantify altered MBF.

Animals↗
PubMed2001

Characterization of contraction and perfusion in the lateral border zone between normal and ischemic myocardium following coronary occlusion by myocardial contrast echocardiography.

We performed myocardial contrast echocardography with power Doppler imaging during left anterior descending occlusion in 10 dogs, and found that video intensity and dyssynergy in lateral border zones of ischemic myocardium were present, but the video intensity was significantly lower than adjacent nonischemic zones. The results of this study demonstrate that levels of perfusion and contraction, which are intermediate between normal and central ischemic zones, are observed in the border zone with coronary occlusion by myocardial contrast echocardography, and may have implications in identifying myocardium that will be spared necrosis and in measuring ultimate infarct size.

Albumins↗
PubMed2001

Ultrasonographic assessment of coronary flow reserve and abdominal fat in obesity.

Recent technological advances in transthoracic Doppler echocardiography (TTDE) have provided noninvasive measurement of coronary flow velocity reserve (CFVR). We aimed to quantitate a correlation between endothelial dysfunction and fat distribution. In 36 patients with obesity, 16 with noninsulin-dependent diabetes mellitus (DM) and 12 healthy volunteers, coronary flow velocity was measured at the distal site of the left anterior descending branch. CFVR was defined as the ratio of hyperemic (IV infusion of 0.15 mg/kg/min adenosine) to basal peak diastolic flow velocity. Abdominal wall fat index (AWFI) was estimated by ultrasonography. Insulin resistance was quantified by the euglycemic hyperinsulinemic clump method. AWFI was significantly related to CFVR (r = -0.46, p = 0.011) and insulin resistance (r = -0.71, p < 0.0001). CFVR could be noninvasively evaluated using TTDE. Coronary endothelial dysfunction indicated as CFVR, body fat distribution and insulin resistance was quantitatively correlated in obesity.

Abdomen↗
PubMed2001

Quantitative assessment of myocardial perfusion during graded coronary stenosis by real-time myocardial contrast echo refilling curves.

OBJECTIVES: The present study examined the ability of real-time myocardial contrast echocardiography (MCE) to delineate abnormalities produced by graded coronary stenoses and to correlate signal intensity (SI) parameters derived from destruction/refilling curves with regional myocardial blood flow (MBF) and contractile function. BACKGROUND: Recent technological advances have enabled myocardial opacification by MCE to be achieved during real-time imaging. METHODS: In eight open-chest dogs, we created LAD occlusion and graded stenoses that were either flow-limiting at rest (FLS) or reduced adenosine hyperemia (non-flow-limiting at rest = NFLS). Myocardial contrast echo used Optison infusion and low-energy real-time power pulse inversion imaging. High-energy FLASH frames destroyed bubbles every 15 cardiac cycles. Myocardial SI-versus-time plots were fitted to a one-exponential function to obtain the rate of SI rise (b) and peak SI in the last frame. RESULTS: Dyssynergy was not observed during any NFLS, but perfusion abnormalities were. Visual detection of decreased opacification was possible with severe NFLS and FLS. b demonstrated a significant reduction with severe NFLS and near significant with moderate NFLS; peak SI did not. All exponential parameters were significantly decreased with FL stenosis and occlusion. The MBF ratio in LAD/LCx beds (fluorescent microspheres) correlated with b (r = 0.79) and the product of the peak SI and b (r = 0.80). CONCLUSIONS: In an open-chest dog model, parameters derived from microbubble refilling of the imaging field by real-time MCE correlate well with myocardial blood flow and can identify coronary stenosis.

Albumins↗
PubMed2001

Effect of cibenzoline, a class ia antiarrhythmic agent, on left ventricular diastolic function in hypertrophic cardiomyopathy.

We aimed to investigate whether the improvement of left ventricular (LV) diastolic function by cibenzoline, a class Ia antiarrhythmic drug, in hypertrophic obstructive cardiomyopathy (HOCM) is due to LV afterload reduction or a primary lusitropic effect on LV. Twenty-three patients with hypertrophic cardiomyopathy (11; HOCM, 12; non-obstructive HCM; HNCM) were examined. Pulsed-wave Doppler, color M-mode and tissue Doppler echocardiography were performed before and 90 minutes after oral administration of cibenzoline (300 mg), and were compared with a treatment of bisoprolol (5 mg/day, 10 days). Early (E) and late diastolic LV inflow velocity, E flow propagation velocity (FPV) and early diastolic mitral annulus velocity (Ea) were measured. E/FPV and E/Ea were calculated as indices of LV filling pressure. LV outflow pressure gradients estimated using continuous-wave Doppler in HOCM markedly decreased after cibenzoline (83 +/- 42 to 40 +/- 33 mmHg, p < 0.005) and bisoprolol (44 +/- 40 mmHg, p < 0.005). Following cibenzoline, E/FPV and E/Ea were significantly decreased in both HOCM (1.75 +/- 0.53 to 1.32 +/- 0.28, p < 0.05, 18.9 +/- 6.2 to 14.8 +/- 5.0, p < 0.05, respectively) and HNCM (1.75 +/- 0.58 to 1.41 +/- 0.73, p< 0.05, 13.0 +/- 4.3 to 9.7 +/- 3.6, p< 0.01, respectively). Those in HNCM did not change by bisoprolol. Cibenzoline improved LV diastolic function in HCM, whereas bisoprolol did not affect it. Thus, the primary lusitropic effect of cibenzoline rather than LV after load reduction might have contributed to the improvement of diastolic function in HOCM.

Administration, Oral↗
PubMed2001

Accuracy and reproducibility of coronary flow rate assessment by real-time contrast echocardiography: in vitro and in vivo studies.

Real-time myocardial contrast echo (MCE) provides the potential to assess myocardial blood flow from time-intensity refilling curves after high-energy bubble destruction. This study validated the accuracy of this approach and the effect of specific examination variables and instrument settings on results. The effects of examination depth and angle as well as dynamic range, pulse repetition frequency, and line density were assessed with the use of in vitro incremental flow rates produced in an in vitro tissue phantom. In vivo recordings of real-time imaging with an infusion of a contrast agent (Optison) were obtained in 7 open-chest dogs with graded left anterior descending artery stenosis at baseline and during adenosine hyperemia, and were compared with flow probe measurements. After bubble destruction, time-intensity data were fitted to an exponential function, and the rate of intensity increase (b) and peak plateau intensity (A) were derived from refilling curves. In vivo real-time values for b, but not A, correlated closely with flow probe measures (r = 0.93). A similar correlation for b was observed in vitro (r = 0.98). The correlation between flow rate and b was influenced by several examination variables, including depth, angle, and instrument settings. Real-time MCE provides accurate quantification of coronary flow by assessing the rate of microbubble refilling. However, this parameter may be affected by several examination and instrument variables. Therefore, real-time MCE refilling measures are best applied by comparing baseline values with those of stress studies.

Animals↗
PubMed2001

Influence of the angiotensin II receptor antagonist losartan on diuretic-induced metabolic effects in elderly hypertensive patients: comparison with a calcium channel blocker.

OBJECTIVE: Diuretic therapy frequently induces undesirable biochemical changes and side effects. We compared metabolic effects of a low-dose diuretic (D) given in combination with an angiotensin II receptor antagonist, losartan (L), with those resulting from a diuretic given in combination with a calcium channel blocker, slow-release nifedipine (N). MATERIAL AND METHODS: Thirty-seven elderly patients with mild to moderate hypertension (mean age: 71 +/- 3 years) were treated with either L+D (n = 18) or N+D (n = 19) for 1 year. Diuretic therapy included low-dose trichlormethiazide or low-dose furosemide in numbers of patients that were similar between L+D and N+D groups. Blood pressure, serum electrolytes, uric acid, blood glucose, renal function and lipid parameters were measured at baseline, 6 months and 1 year. RESULTS: Effective blood pressure control was observed in both groups at 6 months, and with further improvement at 1 year. Serum potassium was significantly decreased from baseline at 6 months (p < 0.01) and 1 year (p < 0.01) in the N+D group, but not in the L+D group. Serum uric acid was significantly increased from baseline at 6 months (p < 0.01) and 1 year (p < 0.01) in the N+D group, but had minimally decreased at 1 year in the L+D group (p < 0.1). Blood glucose, renal function and lipid parameters did not change in either group. CONCLUSION: The combination of losartan and low-dose diuretics effectively treated hypertension in elderly patients while minimizing the metabolic consequences of diuretic therapy. Larger trials will be necessary to confirm this finding.

Aged↗
PubMed2000

Assessment of coronary stenosis severity and transmural perfusion gradient by myocardial contrast echocardiography: comparison of gray-scale B-mode with power Doppler imaging.

BACKGROUND: The present study (1) compared the ability of power Doppler imaging with that of gray-scale B-mode tissue imaging to opacify the myocardium and detect coronary stenosis by myocardial contrast echocardiography and (2) compared the response of video intensity (VI) to variable pulsing intervals for each modality. METHODS AND RESULTS: Four grades of left anterior descending coronary artery (LAD) stenoses were created in 9 open-chest dogs. Stenoses reduced resting LAD flow by 25%, 50%, 75%, and 100% of baseline by flow probe. Myocardial contrast echocardiography was performed during varying ECG gated pulsing intervals (PIs) from 1:1 to 1:10. By gray-scale imaging, background-subtracted LAD bed VI was less than baseline VI at all PIs for the 100% reduced-flow state but not for any other flow state or interval. By power Doppler imaging, LAD bed VI was less than baseline VI at all intervals for 75% and 100% reduced-flow states but only 1:1 and 1:2 for 25% and 50% reduced-flow states, respectively. Correlation of VI and myocardial blood flow (determined by use of fluorescent microspheres) ratios from stenosed versus normal beds was stronger by power Doppler imaging. A transmural opacification gradient with stenosis was visualized and measured by power Doppler imaging, but it was insignificant by gray-scale imaging. The ratio of endocardial/epicardial flow determined by use of fluorescent microspheres was correlated with VI by power Doppler imaging at all PIs. CONCLUSIONS: Power Doppler imaging has advantages compared with gray-scale imaging in opacifying the myocardium and in detecting coronary stenosis and altered transmural distribution of myocardial perfusion from peak VI. Because VI differences from baseline at long PI vary for mild versus severe (75% and 100%, respectively) reduced-flow states, power Doppler imaging may provide a method to quantify coronary stenoses.

Albumins↗
PubMed2000

Comparison of left ventricular diastolic filling with myocyte bulk modulus using Doppler echocardiography and acoustic microscopy in pressure-overload left ventricular hypertrophy and cardiac amyloidosis.

BACKGROUND: The myocardial bulk modulus has been described as the constitutive properties of the left ventricular (LV) wall and is measured as rho V2 (rho = density, V = sound speed) using acoustic microscopy. HYPOTHESIS: The study was undertaken to assess the relationship between the myocyte bulk modulus and transmitral inflow patterns in patients with pressure-overload LV hypertrophy (LVH) and cardiac amyloidosis (AMD). METHODS: In 8 patients with LVH, 8 with AMD, and 10 controls without heart disease, the transmitral inflow pattern was recorded by Doppler echocardiography before death, and myocardial tissue specimens were obtained at autopsy. The tissue density and sound speed in the myocytes were measured by microgravimetry and acoustic microscopy, respectively. The diameters of the myocytes were measured on histopathologic specimens stained by the elastica Van Gieson method. RESULTS: In the subendocardium, the myocyte bulk modulus was larger in LVH (2.98 x 10(9) N/m2, p < 0.001) and smaller in AMD (2.61 x 10(9) N/m2, p < 0.001) than in the controls (2.87 x 10(9) N/m2). The myocyte diameter in LVH (26 +/- 1 microns) was larger than that in the control (21 +/- 1 microns, p < 0.001) and AMD (20 +/- 1 microns, p < 0.001). The bulk modulus in the subendocardial myocyte significantly correlated with the deceleration time (DT) of the early transmitral inflow (r = 0.689, p = 0.028 in control, r = 0.774, p = 0.024 in LVH, and r = 0.786, p = 0.021 in AMD). CONCLUSION: The changes in the myocyte elasticity as represented by the bulk modulus were limited to the subendocardial layers and may be related to relaxation abnormalities in LVH and a reduction in LV compliance in AMD.

Acoustics↗
PubMed2000

Physical properties of the mitral valve tissue assessed by tissue sound speed in cardiac amyloidosis: relationship to the severity of mitral regurgitation.

Cardiac amyloidosis has been documented to show mitral regurgitation (MR) and a thickened mitral valve (MV) due to amyloid deposits. However, the changes in the physical properties of the thickened MV tissue in cardiac amyloidosis, which may be a causative factor of the MR, have not been described. Physical properties of the tissue, which are expressed by the elastic bulk modulus, can be evaluated by tissue sound speed. If biological tissue is assumed to be fluid-like, the tissue sound speed may be given by c= square root of K/rho, where c is the tissue sound speed, K is the elastic bulk modulus, and rho is the density. A reduction in tissue sound speed indicates a reduction in the elastic bulk modulus of the tissue, assuming that there is little change in rho. This suggests that the tissue is less elastic. The purpose of this study was to assess the physical properties of MV tissue by evaluating the sound speed of the MV tissue in cardiac amyloidosis. MV specimens were obtained at autopsy from 20 control adults without cardiovascular diseases and from 20 patients with cardiac amyloidosis. An acoustic microscope operating at 450 MHz was used to measure the tissue sound speed in the tip and basal portions of the MV tissue. The density of MV tissue was measured by microgravimetry. The severity of the MR had been evaluated by Doppler echocardiography before death, and it was compared with the tissue sound speed measured after death. In cardiac amyloidosis showing mild MR, the tissue sound speed of the MV in the tip portion (1605 +/- 19 m/s) and in the basal portion (1791 +/- 64 m/s) were lower than the corresponding values in control subjects (1637 +/- 42 m/s and 1851 +/- 62 m/s). However, these differences were not statistically significant. In cardiac amyloidosis showing moderate MR, the tissue sound speed of MV in the tip portion (1563 +/- 17 m/s) and in the basal portion (1654 +/- 59 m/s) were significantly lower than the corresponding values in the control subjects (p < 0.001) and the patients with mild MR (p < 0.05). No significant differences were observed in the density of MV tissue among the three groups. Therefore, the low value of the MV tissue sound speed in patients with cardiac amyloidosis indicated a reduced elastic bulk modulus, suggesting the less elasticity of the MV tissue. Furthermore, the patients with moderate MR demonstrated the greater reduction in the tissue sound speed than the patients with mild MR. The data suggest that the changes in physical properties of the MV tissue may be one of the causes of MR in cardiac amyloidosis.

Acoustics↗
PubMed2000

Evaluation of progression in nonrheumatic aortic valvular stenosis by scanning acoustic microscopy.

To investigate distributions of hardness and thickness in nonrheumatic aortic stenosis (AS), scanning acoustic microscopy was used. The acoustic propagation speed (APS: m/s) and thickness at three sites (tip, middle and base) of aortic valve were measured in 18 cusps from 7 surgical patients with AS (late lesion), 27 showing mild lesions from 9 autopsy cases (early lesion) and 18 healthy from 6 autopsy cases (healthy). These were measured in each layer of cusps: fibrosa (F), spongiosa (S) or ventricularis (V). In early lesions, an increase in APS preceded the thickening and distributed in the tip (1666 +/- 107), the three layers of the middle (F: 1782 +/- 121; S: 1590 +/- 38; V: 1636 +/- 59) and the fibrosa of the base (1736 +/- 203). In late lesions, APS of the tip and three layers of the base were markedly increased. Progressive nonrheumatic AS is characterized by increased hardness that precedes the thickening, and its distribution may be related to mechanical stress.

Adult↗
PubMed1999

Feasibility of right ventricular myocardial opacification by contrast echocardiography and comparison with left ventricular intensity.

To demonstrate the feasibility and quantify the intensity of right ventricular (RV) myocardial opacification by myocardial contrast echocardiography (MCE), we analyzed MCE produced by intravenous injection of 0.15 ml/kg of QW7437 in 8 closed-chest dogs. MCE could produce visual opacification of the RV wall similar in time course to that of the left ventricular wall, and the data supported the potential role of MCE in evaluating RV hypertrophy, contraction, and perfusion abnormalities.

Animals↗
PubMed1999

Relationship between myocardial tissue density measured by microgravimetry and sound speed measured by acoustic microscopy.

If myocardial tissue can be assumed to be fluid-like, myocardial tissue elasticity can be estimated by the sound speed of tissue based on the equation K = rho(c)2, where K is the elastic bulk modulus, rho is density, and c is the sound speed of tissue. However, little data exist regarding the relationship between the sound speed of tissue and tissue density. The purpose of the present study was to evaluate the relationship between the sound speed of tissue and tissue density of various diseased myocardia. Myocardial tissue specimens at autopsy were obtained from 10 control patients without cardiovascular disease, 8 patients with pressure overload left ventricular hypertrophy (POLVH), and 8 patients with cardiac amyloidosis (AMD). Myocardial tissue sound speed was measured using a scanning acoustic microscope operating in the frequency of 450 MHz, and tissue density was measured by microgravimetry. The sound speed in POLVH (1639 +/- 17 m/s) was higher and that in AMD (1565 +/- 11 m/s) was lower than that in control patients (1615 +/- 15 m/s) (p < 0.001) at the temperature of 20-22 degrees C. The density in POLVH (1.087 +/- 0.004 g/cm3) was higher and that in AMD (1.072 +/- 0.003 g/cm3) was lower than that in control patients (1.082 +/- 0.003 g/cm3) (p < 0.001). Tissue density correlated with sound speed in all three groups (r = 0.96, p < 0.001). Therefore, myocardial tissue sound speed data obtained by acoustic microscopy enabled us to evaluate tissue elasticity without measuring tissue density directly.

Acoustics↗
PubMed1999

Prolongation of left atrial augmentation after handgrip stress in coronary artery disease: observation using pulsed Doppler flowmetry.

Although alterations in left ventricular diastolic filling dynamics have been observed during myocardial ischemia, few data exist regarding temporal changes in left ventricular filling during recovery. Therefore, the authors evaluated transmitral inflow pattern during and after handgrip exertion in coronary artery disease (CAD) by using Doppler echocardiography. The study population consisted of 18 normal (N) subjects and 47 patients with CAD. Of the CAD patients, 17 had coronary lesions associated with a limited area of underperfused myocardium (seven with good collateral circulation and 10 with distal lesions) (MILD), 15 patients exhibited a proximal lesion in a single vessel (SVD), and 15 patients had significant multivessel disease (MVD). Transmitral inflow velocities were continuously recorded at baseline, during handgrip exercise (50% of maximal for 1 minute), and for 5 minutes of recovery. Mean blood pressure, heart rate, early diastolic (E) and late atrial (A) inflow velocities, A/E ratio, and percent changes in E, A, and A/E from baseline were measured. In N and MILD, respectively, left ventricular inflow pattern returned to baseline at 3 minutes after handgrip (%E: 0.7 +/- 7.6%, 6.4 +/- 13.7%; %A: -0.2 +/- 7.9%, 3.1 +/- 6.5%; %A/E: -0.1 +/- 9.7%, -1.7 +/- 12.9%). In SVD and MVD, respectively, change in left ventricular inflow pattern was continued at 3 minutes after handgrip (%E: 7.2 +/- 9.4%, -4.3 +/- 17.2%, %A: 15.4 +/- 11.7%, 20.4 +/- 14.6%, %A/E: 7.9 +/- 10.0%, 29.2 +/- 25.6%). Increases in A and A/E in SVD and MVD were significantly higher than in N and MILD. Impaired left ventricular inflow pattern was observed at 3 minutes after handgrip in CAD, which may be reflected from prolonged impairment of diastolic function produced by ischemia. Therefore, temporal observation of left ventricular inflow pattern using the handgrip stress Doppler method may be useful for detection or follow-up of CAD.

Aged↗
PubMed1999

Evaluation of left atrial wall elasticity using acoustic microscopy.

Left atrial wall elasticity is one of the important factors regulating left atrial stiffness and functions. The authors evaluated left atrial wall elasticity by measuring the sound speed through the left atrial wall, based on the hypothesis that high elasticity tissues will yield larger sound speed values through the tissue, and examined age-associated changes in left atrial wall elasticity. Left atrium specimens were obtained from 30 normal subjects (age, 15-95 years) at autopsy. An acoustic microscope, operating at 450 MHz, was used to measure the sound speed in the endocardium and the myocardium of the left atrium. The sound speeds in endocardium and myocardium demonstrated significant correlation with age (r = 0.74, p<0.0001 and r = 0.47, p<0.01, respectively). These findings indicate that left atrial wall elasticity increased with advancing age. These changes may lead to deterioration of left atrial compliance and eventual left atrial failure in older subjects.

Adolescent↗
PubMed1999

Cyclic variation of thickness in an age-related thick mitral valve observed by transthoracic echocardiography.

The cyclic variation of thickness during the cardiac cycle in age-related degenerative mitral valve (MV) has not been reported. Transthoracic echocardiography was used to evaluate the cyclic alteration in MV thickness in 40 patients with age-related MV thickening (diastolic MV thickness > or = 4 mm, age 70 +/- 14 years), 10 with mitral valve prolapse (MVP, age 49 +/- 11 years), 10 with rheumatic mitral stenosis (MS, age 66 +/- 9 years), and 31 control subjects (diastolic MV thickness < or = 3.6 mm, 53 +/- 17 years). After determination of the site of maximal thickness during diastole, the maximal and minimal thickness during systole of the anterior MV were measured. The percent change in MV thickness from diastole to systole (%deltaT) was calculated. The mitral regurgitation (MR) area was measured on color Doppler echocardiogram. The %deltaT (mean +/- sd) in age-related thickened MV and MVP groups were similar and significantly greater than that in control (60 +/- 8%, 61 +/- 6% vs 32 +/- 9%, p < 0.001). MR area was significantly greater in the age-related thickened MV group than that in controls (160 +/- 205 mm2 vs 14 +/- 40 mm2, p < 0.05). The %deltaT in MS (10 +/- 6%) was smallest (p < 0.001). A large cyclic alteration in valvular thickness was observed in the age-related degeneration of the MV and may be the cause of large MR despite no leaflet prolapse. The echocardiographic assessment of cyclic variation of MV thickness is feasible for estimating the histologic damage in thick MV.

Adolescent↗
PubMed1999

Tissue characterization of myocardial cells by use of high-frequency acoustic microscopy: differential myocyte sound speed and its transmural variation in normal, pressure-overload hypertrophic, and amyloid myocardium.

The purpose of the present study was to evaluate the acoustic properties of myocytes in normal, pressure-overload hypertrophic, and amyloid myocardium. Myocardial tissue specimens at autopsy were obtained from 10 subjects without cardiovascular disease, six patients with left ventricular (LV) hypertrophy, and six patients with cardiac amyloidosis. Sound speed of myocytes was measured at subendocardial and subepicardial regions in myocardium by use of a high-frequency (450 MHz) acoustic microscope. In normal myocardium, the sound speed of myocytes was significantly higher in subendocardial region (1,728+/-19 m/sec) than in subepicardial region (1,645+/-22 m/sec) (p<0.0001). A significantly higher sound speed of myocytes was observed in the subendocardial region in LV hypertrophic myocardium (1,779+/-19 m/sec) than that in normal myocardium (p<0.001). In amyloid myocardium, a significantly lower sound speed of myocytes was observed in subendocardial (1,560+/-8 m/sec) and subepicardial (1,594+/-48 m/sec) regions than that in respective regions of the normal myocardium (p<0.0001 and p<0.05, respectively). Transmural variation in sound speed of myocytes measured by high-frequency acoustic microscopy existed in normal left ventricle. The differential myocyte sound speed and its transmural variation was observed in LV hypertrophic and amyloid myocardium as compared with normal myocardium. High-frequency acoustic microscopy can be a promising technique for myocardial tissue characterization at the myocyte level.

Acoustics↗