| 1. |
- Sun, Y, et al.
(författare)
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Estimation of volume flow rate by surface integration of velocity vectors from color Doppler images.
- 1995
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795 .- 0735-1097 .- 1558-3597. ; 8:6, s. 904-914
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Tidskriftsartikel (refereegranskat)abstract
- A new Doppler echocardiographically based method has been developed to quantify volume flow rate by surface integration of velocity vectors (SIVV). Electrocardiographic-gated color Doppler images acquired in two orthogonal planes were used to estimate volume flow rate through a bowl-shaped surface at a given time and distance from the probe. To provide in vitro validation, the method was tested in a hydraulic model representing a pulsatile flow system with a restrictive orifice. Accurate estimates of stroke volume (+/- 10%) were obtained in a window between 1.2 and 1.6 cm proximal to the orifice, just before the region of prestenotic acceleration. By use of the Bernoulli's equation, the estimated flows were used to generate pressure gradient waveforms across the orifice, which agreed well with the measured flows. To demonstrate in vivo applicability, the SIVV method was applied retrospectively to the determination of stroke volume and subaortic flow from the apical three-chamber and five-chamber views in two patients. Stroke volume estimates along the left ventricular outflow tract showed a characteristic similar to that in the in vitro study and agreed well with those obtained by the Fick oxygen method. The region where accurate measurements can be obtained is affected by instrumental factors including Nyquist velocity limit, wall motion filter cutoff, and color flow sector angle. The SIVV principle should be useful for quantitative assessment of the severity of valvular abnormalities and noninvasive measurement of pulsatile volume flows in general.
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| 2. |
- Aburawi, Elhadi, et al.
(författare)
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Coronary Flow in Neonates with Impaired Intrauterine Growth.
- 2012
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Ingår i: Journal of the American Society of Echocardiography. - : Elsevier BV. - 1097-6795 .- 0894-7317. ; 25:3, s. 313-318
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Subclinical myocardial injury has been reported in newborns with fetal weights < 2 SDs for gestational age. Intrauterine growth restriction might affect cardiac function and coronary flow (CF). METHODS: Seventeen newborns with intrauterine growth restriction and 15 age-matched healthy controls were enrolled in the study. Blood flow in the umbilical artery and maternal uterine artery was assessed using Doppler velocimetry. Cardiac function and left anterior descending coronary artery CF were measured using transthoracic Doppler echocardiography at 1 week of age. RESULTS: The mean growth deviation of the newborns from normal was -2.5 ± 0.2 SDs. Percentage left ventricular shortening fraction was 39 ± 4.3% in patients and 42 ± 4.1% in controls (P = .40), and the mean left ventricular mass index was 86.6 g/m(2) in patients and 73.7 g/m(2) in controls (P < .01). The mean left anterior descending coronary artery diameter was 0.99 ± 0.1 mm in patients and 0.8 ± 0.1 mm in controls (P = .002). The left anterior descending coronary artery flow velocity-time integral was correlated with left ventricular mass index (r = 0.31, P = .007) and with mitral peak E/A ratio (r = 0.74, P = .01). Intrauterine growth restriction was associated with increased peak flow velocity in diastole (34.5 ± 4 vs 19 ± 6 cm/sec in controls, P = .0001), as well as increased CF (37 ± 7.3 vs 8.2 ± 3.0 mL/min in controls, P = .001). CONCLUSIONS: CF is significantly increased in neonates with impaired intrauterine growth. Left ventricular mass index is increased, but systolic and diastolic function remains normal. The clinical significance of increased CF is unclear, but it might lead to decreased CF reserve.
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| 3. |
- Aburawi, Elhadi, et al.
(författare)
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Effects of Balloon Valvuloplasty on Coronary Blood Flow in Neonates With Critical Pulmonary Valve Stenosis Assessed With Transthoracic Doppler Echocardiography.
- 2009
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Ingår i: Journal of the American Society of Echocardiography. - : Elsevier BV. - 1097-6795 .- 0894-7317. ; 22, s. 165-169
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Treating pulmonary valve stenosis with balloon valvuloplasty (BV) is a good model to study the effect of right ventricular (RV) pressures on coronary flow. METHODS: Transthoracic Doppler echocardiography was used to register coronary flow in 10 age-matched healthy controls and 7 neonates before and 1 day after BV. RESULTS: Left ventricular fractional shortening and cardiac output increased significantly after BV. Right coronary artery diameter decreased from 1.2 +/- 0.2 to 1.1 +/- 0.1 mm (P < .02). Posterior descending coronary artery flow parameters decreased significantly, with blood flow decreasing from 8.4 to 5.7 +/- 1.9 mL/s (P < .003). RV end-diastolic pressure and RV systolic pressure explained almost totally the variation in coronary flow (r(2) = 0.87). CONCLUSIONS: RV end-diastolic pressure and RV systolic pressure determined coronary flow in neonates with critical pulmonary valve stenosis. Cardiac output and left ventricular fractional shortening increased after pulmonary valve BV.
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| 4. |
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| 5. |
- Arnold, MF, et al.
(författare)
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Editorial: Does atrioventricular ring motion always distinguish constriction from restriction? A Doppler myocardial imaging study
- 2001
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Ingår i: Journal of the American Society of Echocardiography. - : Elsevier BV. - 0894-7317 .- 1097-6795. ; 14:5, s. 391-395
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Constrictive pericarditis and restrictive cardiomyopathy can be difficult to differentiate on clinical examination. Cardiac ultrasonography is increasingly being used as the noninvasive method of choice for confirming the specific morphologic and hemodynamic abnormalities associated with either condition. Interrogation of atrioventricular valve plane motion by Doppler myocardial imaging (DMI) has been suggested as a valuable new approach that can help differentiate one from the other. We report the color DMI, pulsed DMI, and strain rate findings in 2 cases of constrictive pericarditis in which consideration of the annular motion pattern alone would not have allowed such differentiation.
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| 6. |
- Barclay, Susan A, et al.
(författare)
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The shape of the proximal isovelocity surface area varies with regurgitant orifice size and distance from orifice : computer simulation and model experiments with color M-mode technique.
- 1993
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795. ; 6:4, s. 433-445
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Tidskriftsartikel (refereegranskat)abstract
- The hemispheric proximal isovelocity surface area method for quantification of mitral regurgitant flow (i.e., Qc = 2 pi r2v), where 2 pi r2 is the surface area and v is the velocity at radius r, was investigated as distance from the orifice was increased. Computer simulations and steady flow model experiments were performed for orifices of 4, 6, and 8 mm. Flow rates derived from the centerline velocity and hemispheric assumption were compared with true flow rates. Proximal isovelocity surface area shape varied as distance from each orifice was increased and could only be approximated from the hemispheric equation when a certain distance was exceeded: > 7, > 10, and > 12 mm for the 4, 6, and 8 mm orifices, respectively. Prediction of relative error showed that the best radial zone at which to make measurements was 5 to 9, 6 to 14 and 7 to 17 mm for the 4, 6, and 8 mm orifices, respectively. Although effects of a nonhemispheric shape could be compensated for by use of a correction factor, a radius of 8 to 9 mm can be recommended without the use of a correction factor over all orifices studied if a deviation in calculated as compared with true flow of 15% is considered acceptable. These measurements therefore have implications for the technique in clinical practice.
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| 7. |
- Bech-Hanssen, O, et al.
(författare)
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Aortic prosthetic valve design and size : Relation to Doppler echocardiographic findings and pressure recovery - An in vitro study
- 2000
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795. ; 13:1, s. 39-50
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Tidskriftsartikel (refereegranskat)abstract
- The extent to which Doppler echocardiography information can be used in the assessment of prosthesis hemodynamic performance is still controversial. The goals of our study were to assess the importance of valve design and size both on Doppler echocardiography findings and on pressure recovery in a fluid mechanics model. We performed Doppler and catheter measurements in the different orifices of the bileaflet St Jude (central and side orifices), the monoleaflet Omnicarbon (major and minor orifices), and the stented Biocor porcine prosthesis. Net pressure gradients were predicted from Doppler flow velocities, assuming either independence or dependence of valve size. The peak Doppler estimated gradients (mean +/- SD for sizes 21 to 27) were 21 +/- 10.3 rum Hg for St Jude, 18 +/- 9.3 mm Hg for Omnicarbon, and 37 +/- 14.5 mm Hg for Biocor (P <.05 for St Jude and Omnicarbon vs Biocor). The pressure recovery (proportion of peak catheter pressure) was 53% +/- 8.6% for central-St Jude, 29% +/- 8.9% for side-St Jude, 20% +/- 5.6% for major-Omnicarbon, 23% +/- 7.4% for minor-Omnicarbon, and 18% +/- 3.6% for Biocor (P <.05 for central-St Jude and side-St Jude vs Omnicarbon and Biocor). Valve sizes (2) significantly influenced pressure recovery (y in percentage) (central-St Jude: y = 3.7x - 35.9, r = 0.88, P =.0001, major-Omnicarbon: y = 2.1x - 30.3, r = 0.85, P =.0001). By assuming dependence of valve size, Doppler was able to predict net pressure gradients in St Jude with a mean difference between net catheter and Doppler-predicted gradient of - 3.8 +/- 2.5 mm Hg. In conclusion, prosthetic value design and size influence the degree of pressure recovery, making Doppler gradients potentially misleading in both the assessment of hemodynamic performance and the comparison of one design with another. The preliminary results indicate that net gradient can be predicted from Doppler gradients,
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| 8. |
- Bech-Hanssen, O., et al.
(författare)
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Net Pressure Gradients in Aortic Prosthetic Valves can be Estimated by Doppler
- 2003
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795. ; 16:8, s. 858-866
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Tidskriftsartikel (refereegranskat)abstract
- Background: In aortic prosthetic valves, both the Doppler-estimated gradients and orifice areas are misleading in the assessment of hemodynamic performance. The parameter of major interest is the net pressure gradient after pressure recovery (PR). We, therefore, investigated, in vitro, our ability to predict the net pressure gradient and applied the formulas in a representative patient population with 2 different valve designs. Methods: We studied the St Jude Medical (SJM) standard valve (size 19-27) and SJM Biocor (size 21-27) in an in vitro steady-flow model with simultaneous Doppler-estimated pressure and catheter pressure measurements. Using echocardiography, we also studied patients who received the SJM (n = 66) and SJM Biocor (n = 45). Results: In the SJM, we observed PR both within the prosthesis and aorta, whereas in the SJM Biocor, PR was only present in the aorta. We estimated the PR within the valve and within the aorta separately from echocardiographic in vitro data, combining a regression equation (valve) with an equation on the basis of fluid mechanics theory (aorta). The difference between estimated and catheter-obtained net gradients (mean ± SD) was 0.6 ± 1.6 mm Hg in the SJM and - 0.2 ± 1.9 mm Hg in the SJM Biocor. When these equations were applied in vivo, we found that PR had an overall value of 57 ± 7% of the peak Doppler gradient in the SJM and 33 ± 9% in the SJM Biocor. Conclusions: The in vitro results indicate that it is possible to predict the net pressure gradient by Doppler in bileaflet and stented biologic valves. Our data indicate that important PR is also present in stented biologic valves.
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| 9. |
- Bech-Hanssen, Odd, 1956, et al.
(författare)
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Pulmonary Hypertension Phenotype Can Be Identified in Heart Failure With Reduced Ejection Fraction Using Echocardiographic Assessment of Pulmonary Artery Pressure With Supportive Use of Pressure Reflection Variables
- 2023
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Ingår i: Journal of the American Society of Echocardiography. - : Elsevier BV. - 0894-7317. ; 36:6, s. 604-614
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Tidskriftsartikel (refereegranskat)abstract
- Background: Pulmonary hypertension (PH) is frequent in patients with heart failure and reduced ejection fraction (HFrEF) with 2 different phenotypes: isolated postcapillary PH (IpcPH) and, with the worst prognosis, combined pre- and postcapillary PH (CpcPH). The aims of the present echocardiography study were to investigate (1) the ability to identify PH phenotype in patients with HFrEF using the newly adopted definition of PH (mean pulmonary artery pressure >20 mm Hg) and (2) the relationship between PH phenotype and right ventricular (RV) function. Methods: One hundred twenty-four patients with HFrEF consecutively referred for heart transplant or heart failure workup were included with echocardiography and right heart catheterization within 48 hours. We estimated systolic pulmonary artery pressure (sPAPDoppler) and used a method to detect increased pulmonary vascular resistance (>3 Wood units) based on predefined thresholds of 3 pressure reflection (PRefl) variables (the acceleration time in the RV outflow tract [RVOT], the interval between peak RVOT and peak tricuspid regurgitant velocity, and the RV pressure augmentation following peak RVOT velocity). Results: Using receiver operator characteristic analysis in a derivation group (n = 62), we identified sPAPDoppler ≥35 mm Hg as a cutoff that in a test group (n = 62) increased the likelihood of PH 6.6-fold. The presence of sPAPDoppler >40 mm Hg and 2 or 3 positive PRefl variables increased the probability of CpcPH 6- to 8-fold. A 2-step approach with primarily assessment of sPAPDoppler and the supportive use of PRefl variables in patients with mild/moderate PH (sPAPDoppler 41-59 mm Hg) showed 76% observer agreement and a weighted kappa of 0.63. The steady-state (pulmonary vascular resistance) and pulsatile (compliance, elastance) vascular loading are increased in both IpcPH and CpcPH with a comparable degree of RV dysfunction. Conclusions: The PH phenotype can be identified in HFrEF using standard echocardiographic assessment of pulmonary artery pressure with supportive use of PRefl variables in patients with mild to moderate PH.
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| 10. |
- Bjällmark, Anna, et al.
(författare)
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Velocity tracking - a novel method for quantitative analysis of longitudinal myocardial function
- 2007
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Ingår i: Journal of the American Society of Echocardiography. - : Elsevier. - 0894-7317 .- 1097-6795. ; 20:7, s. 847-856
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Tidskriftsartikel (refereegranskat)abstract
- Doppler tissue imaging is a method for quantitative analysis of longitudinal myocardial velocity. Commercially available ultrasound systems can only present velocity information using a color Dopplerbased overlapping continuous color scale. The analysis is time-consuming and does not allow for simultaneous analysis in different projections. We have developed a new method, velocity tracking, using a stepwise color coding of the regional longitudinal myocardial velocity. The velocity data from 3 apical projections are presented as static and dynamic bull's-eye plots to give a 3-dimensional understanding of the function of the left ventricle. The static bull's-eye plot can display peak systolic velocity, late diastofic tissue velocity, or the sum of peak systolic velocity and early diastolic tissue velocity. Conversely, the dynamic bull's-eye plot displays how the myocardial velocities change over one heart cycle. Velocity tracking allows for a fast, simple, and hituitive visual analysis of the regional longitudinal contraction pattern of the left ventricle with a great potential to identify characteristic pathologic patterns.
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| 11. |
- Bolger, A F, et al.
(författare)
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Understanding continuous-wave Doppler signal intensity as a measure of regurgitant severity.
- 1997
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795. ; 10:6, s. 613-622
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Tidskriftsartikel (refereegranskat)abstract
- Continuous-wave Doppler signal intensity is commonly expected to reflect the severity of mitral regurgitation. Physical principles predict that alignment of the imaging beam, flow velocity, and turbulence can also be important or even dominant determinants of continuous-wave Doppler signal intensity. The reliability of tracking regurgitant severity with continuous-wave Doppler signal intensity was assessed in vitro with varying volume, velocity, turbulence, and beam alignment. The conditions wherein continuous-wave Doppler signal intensity increased with regurgitant volume were specific but poorly predictable combinations of orifice size, flow volume, and perfect beam alignment. Under other conditions flow velocity and turbulence effects dominated, and continuous-wave Doppler signal intensity did not reflect changing regurgitant volume. Continuous-wave Doppler signal intensity-based impressions of regurgitant severity may be unreliable and even misleading under some circumstances.
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| 12. |
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| 13. |
- Clemmensen, Tor Skibsted, et al.
(författare)
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Left Ventricular Pressure-Strain-Derived Myocardial Work at Rest and during Exercise in Patients with Cardiac Amyloidosis
- 2020
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Ingår i: Journal of the American Society of Echocardiography. - : MOSBY-ELSEVIER. - 0894-7317 .- 1097-6795. ; 33:5, s. 573-582
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Tidskriftsartikel (refereegranskat)abstract
- Background: Left ventricular pressure-strain-derived myocardial work index (LVMWI) is a novel, noninvasive method for left ventricular (LV) function evaluation in relation to LV pressure dynamics. LV global longitudinal strain (LVGLS) has proven benefit for diagnosis and risk stratification in patients with cardiac amyloidosis (CA), but LVGLS does not adjust for loading conditions. The aim of the present study was to characterize LVMWI at rest and during exercise in patients with CA. Methods: A total of 155 subjects were retrospectively included. These subjects comprised 100 patients with CA and 55 healthy control subjects. All patients had previously undergone comprehensive two-dimensional echocardiographic examinations at rest. Furthermore, a subgroup 27 patients with CA and 41 control subjects was examined using sennisu pine exercise stress echocardiography. Results: Patients with CA had significantly lower LVGLS, LVMWI, and LV myocardial work efficiency (LVMWE) than control subjects (P < .0001 for all). The reduction in LV myocardial performance was more pronounced in the basal segments, which led to significant alterations in the average apical-to-basal segmental ratios between patients with CA and control subjects (LVGLS, 2.6 [1.9 to 4.1] vs 1.3 [1.2 to 1.5]; LVMWI, 2.6 [1.7 to 3.8] vs 1.3 [1.1 to 1.5]; LVMWE, 1.1 [1.0 to 1.3] vs 1.0 [1.0 to 1.1]; P < .0001 for all). The average increase in LVMWI from rest to peak exercise was 1,974 mm Hg% (95% CI, 1,699 to 2,250 mm Hg%; P < .0001) in control subjects and 496 mm Hg% (95% CI, 156 to 835 mm Hg%; P < .01) in patients with CA. The absolute numeric LVGLS increase was 5.6% (95% CI, 3.9% to 7.3%; P < .0001) in control subjects and only 1.2% (95% CI, -0.9% to 3.3%; P = .26) in patients with CA (between groups, P < .0001) from rest to peak exercise. The LVMWI increase in patients with CA was mediated by improvement in the apical segments (P < .0001), whereas there was no significant LVMWI alterations in the midventricular or basal segments. LVMWE remained stable during exercise in control subjects (Delta -0.6%; 95% CI, -2.5% to 1.2%; P = .50) but decreased significantly in patients with CA (Delta -2.5%; 95% CI, -4.8% to -0.2%; P < .05). Conclusions: Patients with CA have significantly reduced magnitude of LVMWI compared with healthy control subjects. With exercise, the differences are even more pronounced. Even though LVMWI increased with exercise, LVMWE decreased, suggesting inefficient myocardial energy exploitation in patients with CA.
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| 14. |
- Dencker, Magnus, et al.
(författare)
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Bileaflet blood cysts on the mitral valve in an adult.
- 2009
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Ingår i: Journal of the American Society of Echocardiography. - : Elsevier BV. - 1097-6795 .- 0894-7317. ; 22:9, s. 5-1085
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Tidskriftsartikel (refereegranskat)abstract
- Blood cysts within the heart are very rare entities in adults. The authors present possibly the first ever case in which blood cysts were found on both mitral valve leaflets. A 65-year-old woman was referred for transthoracic echocardiography because of vague chest discomfort. Transthoracic echocardiography displayed echo-free cysts on the tips of both mitral valve leaflets. Subsequent transesophageal echocardiography confirmed this finding. The blood cysts were successfully surgically removed.
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| 15. |
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| 16. |
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| 17. |
- Eidenvall, Lars, et al.
(författare)
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Two-dimensional color Doppler flow velocity profiles can be time corrected with an external ECG-delay device.
- 1992
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795. ; 5:4, s. 405-413
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Tidskriftsartikel (refereegranskat)abstract
- Although two-dimensional ultrasound color flow imaging is often considered to be a real-time technique, the acquisition time for two-dimensional color images may be up to 200 msec. Time correction is therefore necessary to obtain correct flow velocity profiles. We have developed a time-correction method in which a specially designed unit detects the QRS complex from the patient and creates a trig pulse that is delayed incrementally in relation to the QRS complex. This trig pulse controls the acquisition of the ultrasound images. A number of consecutively delayed images, with known incremental delay between the sweeps, can thus be stored in the memory of the echocardiograph and transferred digitally to a computer. The time-corrected flow velocity profile is obtained by interpolation of data from the time-delayed profiles. The system was evaluated in a Doppler string phantom test. With this technique it is possible to study time-corrected flow velocity profiles without the need to alter existing ultrasound Doppler equipment.
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| 18. |
- Emilsson, Kent, 1963-, et al.
(författare)
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The relation between mitral annulus motion and ejection fraction : a nonlinear function.
- 2000
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Ingår i: Journal of the American Society of Echocardiography. - : Elsevier BV. - 0894-7317 .- 1097-6795. ; 13:10, s. 896-901
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Tidskriftsartikel (refereegranskat)abstract
- In previous studies of the relation between mitral annulus motion (MAM) and left ventricular ejection fraction (EF), a linear relationship has been suggested. In this meta-analysis of 434 patients, we show that the relation is nonlinear and that a linear regression model overestimates EF in the lower range of MAM. The relation is better described by an S function and is influenced by age and heart size.
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| 19. |
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| 20. |
- Escobar Kvitting, John-Peder, 1976-, et al.
(författare)
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How accurate is visual assessment of synchronicity in myocardial motion? An in vitro study with computer-simulated regional delay in myocardial motion : clinical implications for rest and stress echocardiography studies
- 1999
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795. ; 12:9, s. 698-705
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Tidskriftsartikel (refereegranskat)abstract
- Asynchronicity in echocardiographic images is normally assessed visually. No prior quantitative studies have determined the limitations of this approach. To quantify visual recognition of myocardial asynchronicity in echocardiographic images, computer-simulated delay phantom loops were generated from a 3.3 MHz digital image data from a normal left ventricular short-axis heart cycle acquired at 55 frames per second. Six expert observers visually assessed 30 abnormal and 3 normal loops with differing computer-induced delay patterns on 3 occasions and in this optimally simulated environment could recognize only single delays of 89 ms or more. This was improved to 71 ms or more by use of side-by-side (normal versus abnormal) comparative review. Thus visual assessment of clinically important regional delay in rest or stress echo images is limited.
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| 21. |
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| 22. |
- Flachskampf, Frank A, et al.
(författare)
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Overestimation of flow velocity through leaks in mechanical valve prostheses and through small orifices by continuous-wave Doppler.
- 1997
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795. ; 10:9, s. 904-914
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Tidskriftsartikel (refereegranskat)abstract
- The reliability of continuous-wave Doppler flow velocity measurements through small regurgitant lesions, such as in prosthetic leakage, has not been systematically analyzed. To evaluate the accuracy of continuous-wave Doppler in prosthetic valve leakage and small orifices in an in vitro, steady-flow model-flow velocities through the leaks of twelve intact mechanical prostheses and through six circular nozzles (area 0.5 to 20 mm2) were measured at pressure drops between 30 and 105 mm Hg. These results were compared with those predicted by the modified Bernoulli equation. Laser Doppler anemometry of flow velocities through the nozzles was also performed. Despite high correlation, there was substantial overestimation of Bernoulli predicted velocities by echo Doppler in the prosthetic leaks (mean +12.3% +/- 9.4%; range 90.3% to 143.4%). In the nozzles < or = 10 mm2, but not in the largest (20 mm2) nozzle, there was also overestimation of the Bernoulli predicted velocities (mean +6.2% +/- 2%). Laser Doppler anemometry of flow velocities through the nozzles showed slightly lower values than predicted by the Bernoulli equation. Thus, continuous-wave echo Doppler overestimates flow velocities through small orifices. This apparently is, at least in part, due to transit time effects and should be taken into account when using echo Doppler in small (< 10 mm2) orifices, such as in mild to moderate regurgitant lesions and prosthetic valve leakage.
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| 23. |
- Fyrenius, Anna, et al.
(författare)
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Pitfalls in Doppler evaluation of diastolic function : insights from 3-dimensional magnetic resonance imaging
- 1999
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Ingår i: Journal of the American Society of Echocardiography. - Amsterdam : Elsevier Science B.V.. - 0894-7317 .- 1097-6795. ; 12:10, s. 817-826
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Tidskriftsartikel (refereegranskat)abstract
- Ultrasound-Doppler assessment of diastolic function is subject to velocity errors caused by angle sensitivity and a fixed location of the sample volume. We used 3-dimensional phase contrast magnetic resonance imaging (MRI) to evaluate these errors in 10 patients with hypertension and in 10 healthy volunteers. The single (Doppler) and triple (MRI) component velocity was measured at early (E) and late (A) inflow along Doppler-like sample lines or 3-dimensional particle traces generated from the MRI data. Doppler measurements underestimated MRI velocities by 9.4% ± 8.6%; the effect on the E/A ratio was larger and more variable. Measuring early and late diastolic inflows from a single line demonstrated the error caused by their 3-dimensional spatial offset. Both errors were minimized by calculating the E/A ratio from maximal E and A values without constraint to a single line. Alignment and spatial offset are important sources of error in Doppler diastolic parameters. Improved accuracy may be achieved with the use of maximal E and A velocities from wherever they occur in the left ventricle.
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| 24. |
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| 25. |
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