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  • 1
    Electronic Resource
    Electronic Resource
    Enhanced methods for visualizing myocardial perfusion with peripheral venous injection of Levovist®: Application of triggered harmonic imaging and triggered harmonic power Doppler imaging techniques (2000)
    Springer
    The international journal of cardiovascular imaging 16 (2000), S. 233-246 
    Details
    ISSN: 1573-0743
    Keywords: harmonic imaging ; microbubbles ; myocardial contrast echocardiography ; peripheral venous injection ; power Doppler
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objectives:The purpose of this study was to determine whether triggered harmonic imaging (THI) or triggered harmonic power Doppler imaging (THPDI) could obtain the myocardial contrast enhancement using peripheral venous injection of a first generation echocardiographic contrast agent, Levovist®. Methods:In a phantom model, we examined the influence of an acoustic power, harmonic filters, transmitted frequencies and focus positions of transducer on Levovist®. Then fundamental, harmonic or harmonic power Doppler imaging were performed with ECG-triggered imaging in eight closed-chest dogs using bolus injection of Levovist®. Results:In a phantom model, the highest transmission power (Mechanical index 1.6), a medium harmonic filter and a focus position (6 cm) resulted in the best enhanced contrast in both THI and THPDI. Furthermore, higher pulse repetition frequency (5500 Hz) of harmonic power Doppler made clearer enhancement. In animal models, we could not observe the apparent myocardial contrast using triggered fundamental imaging, and the intensity of each region of interest (ROI) of myocardium had not changed significantly. However, homogeneous myocardial contrast could be obtained using THI, which was conditioned on the highest transmission power, a medium harmonic filter same as the phantom model, at a lower transmitted frequency (1.8 MHz) and a focus position, which were located in the middle portion of the left ventricle. The peak intensity of each ROI increased significantly in a gray level. Furthermore, THPDI caused emphasized myocardial contrast visually. Conclusions:These results indicate that THI and THPDI produce obvious MCE using peripheral venous injection of Levovist®.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026592629450
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  • 2
    Electronic Resource
    Electronic Resource
    Involvement of cyclo-oxygenase-generated vasodilating eicosanoid(s) in addition to nitric oxide in endothelin-1-induced endothelium-dependent vasorelaxation in guinea pig aorta (1993)
    Springer
    Heart and vessels 8 (1993), S. 121-127 
    Details
    ISSN: 1615-2573
    Keywords: Endothelin ; Vasodilatation ; Endothelium ; Cyclo-oxygenase-generated vasodilating eicosanoid(s) ; Guinea pig aorta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study investigates the vasodilatory effects of endothelin-1 (ET-1) in isolated guinea pig aortic rings in vitro. Cumulative dose-response curves to ET-1 were constructed and ET-1 actions on prostaglandin F2α (PGF2α)-precontraction were studied in both endothelium-intact and endothelium-denuded preparations, in the presence or absence of a cyclooxygenase inhibitor (indomethacin) and/or nitric oxide inhibitors (NG-nitro-L-arginine methyl ester and hemoglobin). In endothelium-intact preparations, pretreatment with indomethacin (10−5M, 30 min), alone or in combination with NG-nitro-L-arginine methyl ester (L-NAME, 10−4M), significantly augmented the constrictive responses to ET-1, whereas indomethacin, L-NAME, and hemoglobin (10−5M) had no significant effects in the endothelium-denuded preparations. Furthermore, in PGF2α-precontracted, endothelium-intact preparations, ET-1, at a dose of 10−9M, induced initial relaxation followed by subsequent contraction, while it only contracted the endothelium-denuded preparations. The initial relaxation was abolished by indomethacin, but not by L-NAME or hemoglobin. In addition, this relaxation was not inhibited by a specific ETA receptor antagonist, BQ-123 (6 × 10−6M). In addition to the involvement of nitric oxide, these results show the involvement of cyclo-oxygenase-generated vasodilating eicosanoid(s) derived from endothelium in ET-1-induced vasorelaxation in guinea pig aorta in vitro. The results also indicate that this vasorelaxation is mediated by ETB receptor activation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01744796
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  • 3
    Electronic Resource
    Electronic Resource
    Wall composition in intravascular ultrasound layered appearance of human coronary artery (1996)
    Springer
    Heart and vessels 11 (1996), S. 152-159 
    Details
    ISSN: 1615-2573
    Keywords: Intravascular ultrasound ; Coronary atherosclerosis ; Layered appearance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To evaluate the impact of histological factors on the appearance of the wall of the coronary artery by intravascular ultrasound (IVUS), we performed an in vitro study of 34 coronary artery segments from eight autopsied patients. We assumed the coronary cross section to be divided into four equal parts, and assessed the quadrants with maximal and minimal wall thickness by IVUS (30MHz; 4.3Fr; 1 800rpm) and by a histological study. The histological layer thickness and composition were also evaluated in terms of their contribution to the appearance of the ultrasound layer. Fifty-eight quadrants were clearly visible on ultrasound. A threelayered appearance, with inner echogenic, subjacent sonolucent, and outer echogenic layers, was observed in 32 quadrants, while 26 quadrants showed a two-layered appearance, with inner and outer echogenic layers. The thickness of the inner echogenic layer (0.77 ± 0.38mm) was moderately correlated with the intimal thickness (0.51 ± 0.45mm;r = 0.85, standard error of estimate [SEE] = 0.24 mm); however, the correlation was significantly improved when the thickness of the inner echogenic plus sonolucent layers (0.89 ± 0.47mm) was compared with that of the intima plus media (0.69 ± 0.47 mm;r = 0.94, SEE = 0.15 mm;P = 0.012 between the coefficients). Discriminant analysis showed that intimal hyalinization, associated with intimal thickening, was strongly related to the presence of the three-layered appearance on IVUS (F to enter 40.0,P 〈 0.0001). These results indicate that the ultrasound layered appearance of human coronary arteries varies with histological alterations. We suggest that the thickness of the inner echogenic plus sonolucent layers on IVUS represents the intimal plus medial thickness observed by histology, and that the use of this value may be appropriate in the assessment of coronary wall thickening associated with atherosclerosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01745173
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  • 4
    Electronic Resource
    Electronic Resource
    Intravascular ultrasound evidence of angiographically undetected left main coronary artery disease and associated trauma during interventional procedures (1996)
    Springer
    Heart and vessels 11 (1996), S. 262-268 
    Details
    ISSN: 1615-2573
    Keywords: Left main coronary artery ; Intravascular ultrasound ; Atherosclerosis ; Transluminal angioplasty
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To determine the clinical significance of angiographically undetected left main coronary artery (LMCA) disease, we analyzed data from 47 patients, with a mean age of 58 years, who were examined with intravascular ultrasound (3.5Fr, 30MHz). For assessment of atherosclerosis, the lesion area was calculated from the ultrasound images by the formula, {(total vessel area — lumen area)/total vessel area} × 100(%). In 37 LMCA segments of patients with significant distal coronary stenosis (〉50%), the percent intima-media area (the index) was 39 ± 11% (mean ± SD), significantly greater than that of 10 patients without distal disease (27 ± 4%,P 〈 0.01). Among those with significant coronary stenosis, the index was markedly greater in patients with multi-vessel coronary stenosis (46 ± 12%,n = 19) than in patients with single-vessel disease (33 ± 9%,n = 18;P 〈 0.01). At three LMCA sites associated with multi-vessel disease, ultrasound analysis demonstrated disruption of the intima at the site where the guiding catheter for balloon angioplasty had been positioned. These results indicate that LMCA disease is more prominent in patients with multi-vessel distal coronary disease than in those with single vessel disease, even in the absence of angiographic stenosis. We suggest that LMCA trauma can occur where the guiding catheter for angioplasty is positioned, particularly in patients with multi-vessel distal disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01746207
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  • 5
    Electronic Resource
    Electronic Resource
    Usefulness of the subendocardial myocardial velocity gradient in low-dose dobutamine stress echocardiography (2000)
    Springer
    Heart and vessels 15 (2000), S. 11-17 
    Details
    ISSN: 1615-2573
    Keywords: Key words Ischemic heart disease ; Dobutamine stress echocardiography ; M-mode tissue Doppler imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The subendocardial side of myocardium makes a major contribution to left ventricular (LV) contraction and is very susceptible to ischemia. In this study we sought to quantify regional wall motion during low-dose dobutamine stress echocardiography (DSE) by using the myocardial velocity gradient (MVG) derived from tissue Doppler imaging (TDI). We then compared the usefulness of subendocardial MVG with that of transmural MVG in detecting subtle wall motion abnormalities. Fourteen patients (single vessel disease = 6; normal coronary arteries = 8) underwent low-dose DSE (10 μg/kg per min). M-Mode TDI of the LV posterior wall was recorded using a Toshiba SSA-380A combined with custom computer software, and analyzed for both subendocardial and transmural MVG. Visual estimation and transmural MVG failed to clearly demonstrate the differing responses between the nonischemic (systole: 3.0 ± 0.8/s to 4.9 ± 1.9/s, not significant; diastole: −4.3 ± 1.3/s to −5.7 ± 1.4/s, not significant; mean ± SD, P versus ischemic segments) and ischemic (systole: 3.3 ± 1.2/s to 3.8 ± 1.0/s; diastole: −5.4 ± 2.0/s to −5.3 ± 1.1/s) segments during low-dose DSE. Subendocardial MVG demonstrated a significant change in the nonischemic segments (systole: 4.1 ± 1.0/s to 7.7 ± 2.2/s, P = 0.012; diastole: −6.5 ± 1.8/s to −11.3 ± 2.2/s, P = 0.001), whereas the response remained unchanged in the ischemic segments (systole: 4.6 ± 2.4/s to 4.8 ± 1.2/s; diastole: −7.0 ± 1.9/s to −7.3 ± 1.1/s). Subendocardial MVG, particularly diastolic subendocardial MVG, may serve as a useful indicator of subtle ischemic changes in wall motion induced by low-dose DSE.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003800070042
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  • 6
    Electronic Resource
    Electronic Resource
    Attenuated inhibition of adrenergic contraction by nitric oxide in injured guinea pig femoral artery (1997)
    Springer
    Heart and vessels 12 (1997), S. 10-18 
    Details
    ISSN: 1615-2573
    Keywords: Balloon dilatation ; Electric stimulation ; guinea pig femoral artery ; Nitric oxide ; Noradrenaline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present study aimed to examine the altered modulation of adrenergic contraction by nitric oxide and sensory neuropeptides in balloon-injured muscular artery. A guinea pig femoral artery (GPFA) was injured by a newly developed silastic microballoon catheter. The contralateral GPFA served as the control. The studied GPFAs consisted of six groups; control (C) and injured (I) GPFA, isolated at 0 days, and 2 and 8 weeks after injury (C0, I0, C2, I2, C8, and I8). Isometric tension was measured in the presence of indomethacin (10−5M), to exclude effects of cyclo-oxygenase-generated eicosanoids. Endothelial removal with the catheter was confirmed by histological examination. In each group, except for I0, NG-nitro-L-arginine methyl ester (l-NAME, 10−6M) induced significant augmentation of perivascular nerve stimulation (PNS)-evoked adrenergic contraction, which was blocked byl-arginine (3 × 10−4M). The degree ofl-NAME augmentation in I8 was significantly smaller than that in C8 and I2. Capsaicin (10−6M) did not significantly affect PNS-contraction in any group, indicating that there was no sensory neuropeptide involvement in this contraction. In I8, acetylcholine (10−6M)-induced relaxation after noradrenaline (10−5M)-precontraction was significantly smaller than that seen in the other groups, except for I0, which was lacking in acetylcholine-induced relaxation. Histologically, injured GPFAs showed progressive intimal thickening. The present findings thus showed attenuated nitric oxide-mediated inhibition of adrenergic contraction, accompanying intimal thickening, in balloon-injured muscular artery, 8 weeks after injury.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01747497
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  • 7
    Electronic Resource
    Electronic Resource
    Myocardial imaging with 123I-BMIPP in patients with congestive heart failure (1999)
    Springer
    The international journal of cardiovascular imaging 15 (1999), S. 71-77 
    Details
    ISSN: 1573-0743
    Keywords: congestive heart failure ; idiopathic dilated cardiomyopathy ; ischemic cardiomyopathy ; myocardial metabolism ; pulmonary hypertension ; single-photon emission tomography (SPECT)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract First, we studied the diagnostic utility of myocardial imaging with 123I-BMIPP (BMIPP), a 3-methyl-branched fatty acid analog, in patients with various types of cardiomyopathy and left ventricular dysfunction (ejection fraction below 40%) by comparing with myocardial flow tracer imaging. The incidence of a dissociation between myocardial BMIPP and 201Tl distributions (BMIPP〈 201Tl) as a marker of metabolic abnormality in viable tissue varied considerably among various heart diseases. Patients with ischemic cardiomyopathy and the dilated form of hypertrophic cardiomyopathy had a higher incidence while those with idiopathic dilated, alcoholic and hypertensive cardiomyopathy had a lower incidence. These results suggest that the marked difference between ischemic and idiopathic dilated cardiomyopathies may contribute to the differential diagnosis between these two diseases which are main basic abnormalities in congestive heart failure. Second, we investigated the relationship between myocardial BMIPP uptake and ventricular stress in patients with right ventricular pressure overload due to pulmonary hypertension. Myocardial BMIPP uptake in the right ventricle estimated by referring to uptake in the left ventricle showed a significant correlation with mean pulmonary artery pressure (mPAP) and no significant difference with myocardial 99mTc-sestamibi uptake in the 15–81mmHg mPAP range. These results suggest that myocardial utilization of free fatty acid may be preserved in the presence of higher ventricular wall stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006152804670
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  • 8
    Electronic Resource
    Electronic Resource
    Impact of presence of abnormal wall motion on echocardiographic determination of left ventricular function with automated boundary detection technique: re-evaluation (1998)
    Springer
    The international journal of cardiovascular imaging 14 (1998), S. 253-259 
    Details
    ISSN: 1573-0743
    Keywords: automated boundary detection ; echocardiography ; left ventricular function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract It is still unclear whether echocardiography with an automated boundary detection technique (ABD) can accurately determine the left ventricular (LV) volume and function particularly in the presence of LV wall asynergy. We intended to re-evaluate the reliability and application of the ABD, which was based on the acoustic quantification technique (Sonos 2500, Hewlett Packard) for the LV volume measurement in patients without or with LV wall asynergy. A total of 80 patients (mean age 56 years) who underwent left ventriculography (LVG) were divided into two groups. The group A consisted of 29 patients with normal LV wall motion and the group B consisted of 51 patients with generalized or regional LV wall motion abnormality. In group A patients, the LV end-diastolic volume (LVEDV) was 96 ± 25 ml by ABD and 112 ± 33 ml by LVG and those of LV end-systolic volume (LVESV) were 44 ± 14 ml by ABD and 48 ± 17 ml by LVG, thus resulting in the underestimation of LV volume by 12% in average. Under these conditions, the LV ejection fraction (LVEF) by ABD, 54 ± 8%, correlated well with that by LVG, 58 ± 7%. Although underestimation of LV volume by 17% in average also occurred in groups B (N.S.), LVEF was found to correlate well with that by LVG; 27 ± 8% vs 30 ± 11% (r=0.87, SEE=3.1%) for 21 patients with the generalized LV asynergy; 39 ± 10% vs 39 ± 12% (r=0.86. SEE=3.3%) for 30 patients with the regional LV asynergy. These results demonstrate the feasibility of the ABD in determining the LVEF, although underestimation can occur in measuring the absolute LV volume in patients with or without LV asynergy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006060105703
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