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pulsed wave Doppler ultrasound pulsed Doppler ultrasound [keywords]
- Doppler ultrasonographic assessment of maternal and fetal arteries during normal feline gestation. [JOURNAL ARTICLE]
- Anim Reprod Sci 2014 Feb 15.
The aim of this study was to describe Doppler parameters of uterine, umbilical, fetal abdominal aorta, fetal renal and fetal internal carotid arteries, as well as fetal heart rate (FHR), during normal feline gestation. Fifteen, 1-4 years of age, weighing 2.5-3.9kg, domestic short-hair pregnant queens, which were born in our institutional cat colony were included in this study. Color and pulsed-wave Doppler evaluations of uterine arteries were performed every 10 days (Day 0, 10, 20, 30, 40, 50, 60) from mating. Fetal Doppler and M-mode ultrasonography were performed to assess umbilical, fetal abdominal aorta, fetal renal, fetal internal carotid arteries and FHR. Both peak systolic velocity (PSV) and end diastolic velocity (EDV) of uterine artery increased up to parturition (P<0.01), while resistance index (RI) decreased from Day 10 onwards (P<0.01). From Day 40 onwards, RI of umbilical artery diminished, while PSV and EDV augmented (P<0.01). Fetal abdominal aorta (P<0.01), renal (P<0.01) and internal carotid (P<0.01) arteries diminished their RI from Days 40, 60 and 40 onwards, respectively. Both PSV and EDV of these three arteries increased progressively. Fetal heart rate was first registered on Day 20 when it began to increase up to Day 40 and then diminished to the end of gestation (P<0.01). It is concluded that blood flow of uterine, umbilical, fetal abdominal aorta, fetal renal and fetal internal carotid arteries progressively increased during normal feline pregnancy, while FHR rose to mid gestation and then decreased up to parturition.
- Limits of Spatial Resolution for Thermography and Other Non-destructive Imaging Methods Based on Diffusion Waves. [JOURNAL ARTICLE]
- Int J Thermophys 2013.:1617-1632.
In this work the measured variable, such as temperature, is a random variable showing fluctuations. The loss of information caused by diffusion waves in non-destructive testing can be described by stochastic processes. In non-destructive imaging, the information about the spatial pattern of a samples interior has to be transferred to the sample surface by certain waves, e.g., thermal waves. At the sample surface these waves can be detected and the interior structure is reconstructed from the measured signals. The amount of information about the interior of the sample, which can be gained from the detected waves on the sample surface, is essentially influenced by the propagation from its excitation to the surface. Diffusion causes entropy production and information loss for the propagating waves. Mandelis has developed a unifying framework for treating diverse diffusion-related periodic phenomena under the global mathematical label of diffusion-wave fields, such as thermal waves. Thermography uses the time-dependent diffusion of heat (either pulsed or modulated periodically) which goes along with entropy production and a loss of information. Several attempts have been made to compensate for this diffusive effect to get a higher resolution for the reconstructed images of the samples interior. In this work it is shown that fluctuations limit this compensation. Therefore, the spatial resolution for non-destructive imaging at a certain depth is also limited by theory.
- Correlation of myocardial performance index assessed by different echocardiographic methods in patients with acute myocard infarction receiving different reperfusion treatment. [Journal Article]
- Minerva Med 2013 Dec; 104(6):593-604.
Aim:Myocardial performance index (MPI) is a well known prognostic parameter in acute myocardial infarction (AMI) patients, which has been used to assess global cardiac functions. In this study, we aimed to evaluate the corelation between the MPI levels obtained by PW doppler and Tissue doppler ultrasonography with reperfusion in AMI patients.
Methods:Fifty-four consecutive acute ST elevatation myocardial infarction patients, 26 treated with primary percutaneous coronary intervention (PCI) and 28 with thrombolytic therapy (TT); and 15 consecutive healthy controls were included in the study. MPI levels were measured with pulsed-wave (PW) doppler and tissue Doppler ultrasonography in all patients. The isovolumic relaxation time (IVRT), isovolumic contraction time (IVCT) and ejection time (ET) values used to measure MPI levels were determined. Corelation between the time intervals obtained with both methods were evaluated. MPI variations were evaluated in patients treated with PCI and TT. A significant corelation was observed in MPI levels obtained with PW doppler and tissue doppler ultrasonography (P<0.001) as well as between IRT, ICT and ET values (for all parameters; P<0.001). No significant corelation was observed between the MPI levels obtained with PW doppler and tissue doppler ultrasonography in patients treated with primary PTCA and TT (P=0.128, P=0.991, respectively). A significant corelation was observed between the MPI values obtained by PW doppler and tissue doppler ultrasonography with reperfusion interval (P=0.002, P<0.001, respectively).
Conclusion.As a result, tissue Doppler ultrasonography may be used as an alternative to PW doppler to evaluate MPI, which is a well known prognostic factor in AMI. No relation has been observed between MPI values in early phases of AMI with reperfusion pattern, while a connection has been observed between MPI and reperfusion interval.
- Tissue elasticity quantification by acoustic radiation force impulse for the assessment of renal allograft function. [Journal Article, Research Support, Non-U.S. Gov't]
- Ultrasound Med Biol 2014 Feb; 40(2):322-9.
Acoustic radiation force impulse (ARFI) quantification, a novel ultrasound-based elastography method, has been used to measure liver fibrosis. However, few studies have been performed on the use of ARFI quantification in kidney examinations. We evaluated renal allograft stiffness using ARFI quantification in patients with stable renal function (n = 52) and those with biopsy-proven allograft dysfunction (n = 50). ARFI quantification, given as shear wave velocity (SWV), was performed. The resistance index (RI) was calculated by pulsed-wave Doppler ultrasound, and clinical and laboratory data were collected. Morphologic changes in transplanted kidneys were diagnosed by an independent pathologist. Mean SWV was more significantly negatively correlated with estimated glomerular filtration rate (eGFR) (r = -0.657, p < 0.0001) than was RI (r = -0.429, p = 0.0004) in transplanted kidneys. Receiver operating characteristic curve analysis revealed that the sensitivity and specificity of quantitative ultrasound in the diagnosis of renal allograft dysfunction were 72.0% and 86.5% (cutoff value = 2.625), respectively. The latter values were better than those of RI, which were 62.0% and 69.2% (cutoff value = 0.625), respectively. The coefficient of variation for repeat SWV measurements of the middle part of transplanted kidney was 8.64%, and inter-observer agreement on SWV was good (Bland-Altman method, ICC = 0.890). In conclusion, tissue elasticity quantification by ARFI is more accurate than the RI in diagnosing renal allograft function.
- Ultrasound physics. [Journal Article]
- Crit Care Clin 2014 Jan; 30(1):1-24, v.
Bedside ultrasound has become an important modality for obtaining critical information in the acute care of patients. It is important to understand the physics of ultrasound in order to perform and interpret images at the bedside. The physics of both continuous wave and pulsed wave sound underlies diagnostic ultrasound. The instrumentation, including transducers and image processing, is important in the acquisition of appropriate sonographic images. Understanding how these concepts interplay with each other enables practitioners to obtain the best possible images.
- Evaluation of effects of Extracorporeal Shock Wave Lithotripsy on renal vasculature with Doppler ultrasonography. [Journal Article]
- Med Ultrason 2013 Dec; 15(4):273-7.
In this prospective study, we aimed to demonstrate the effects of Extracorporeal Shock Wave Lithotripsy (ESWL) on renal blood flow in patients treated for renal/ ureteral stones.The study group comprised 41 patients (26 males, 15 females, aged between 18-63 years, mean age 45 years), 23 with renal and 18 with ureteral stones, who underwent ESWL between March 2010 and January 2011. Colour Doppler ultrasonography and pulsed wave spectral analysis was performed before, 1 hour, and 7 days after ESWL to both ipsilateral and contralateral kidneys in order to measure resistive index (RI), pulsatility index (PI) and acceleration time (AT) values.One hour after ESWL, RI and PI values showed significant increase from pre-ESWL values in both ipsilateral and contralateral kidneys. However, no significant change was found in AT values. Seven days after ESWL, PI in both ipsilateral and contralateral kidneys and RI in contralateral kidney returned to pre-ESWL values. But, 7 days after ESWL, RI in the ipsilateral kidney did not return to pre-ESWL values, although decrease in RI values were observed. CONCLUSİON: Spectral Doppler analysis can provide valuable information as a non-invasive method to assess the hemodynamic changes and renal microcirculation status in cases managed with ESWL.
- Are levels of NT-proBNP and SDMA useful to determine diastolic dysfunction in chronic kidney disease and renal transplant patients? [Journal Article, Research Support, Non-U.S. Gov't]
- J Clin Lab Anal 2013 Nov; 27(6):461-70.
The aim of the study was to determine the clinical usefulness of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and symmetric dimethylarginine (SDMA) for detection of renal and left ventricular (LV) diastolic dysfunction in chronic kidney disease (CKD) patients and renal transplant (RT) recipients.We included 98 CKD and 44 RT patients. We assessed LV function using pulsed-wave Doppler ultrasound. Diastolic dysfunction was defined when the E:A ratio was <1.Independent predictors of NT-proBNP levels were age, creatinine, and albumin in CKD patients and age and urea in RT patients. Determinants of SDMA in CKD patients were glomerular filtration rate (GFR) and NT-proBNP and creatinine in RT patients. In RT patients with diastolic dysfunction, NT-proBNP and SDMA were significantly higher than in patients without diastolic dysfunction (F = 7.478, P < 0.011; F = 2.631, P < 0.017). After adjustment for GFR, the differences were not seen. In CKD patients adjusted NT-proBNP and SDMA values for GFR were not significantly higher in patients with diastolic dysfunction than in patients without diastolic dysfunction.NT-proBNP is useful for detection of LV diastolic dysfunction in RT recipients. When evaluating both NT-proBNP and SDMA it is necessary to consider GFR as a confounding factor.
- Uterine artery Doppler study in second trimester of pregnancy. [Journal Article]
- Pan Afr Med J 2013.:87.
The uterine artery Doppler has potentials for screening for complications of impaired placentation. This study examines the indices of uterine artery impedance at 22-23 weeks gestation and their relationship with maternal age and parity.Uterine artery colour imaging and pulsed wave Doppler ultrasound was conducted between 22nd and 23rd weeks in 430 pregnancies. The pregnancies were classified into 2 groups: normal and abnormal outcomes. The indices of impedance recorded were pulsatility index, resistance index and the systolic/diastolic ratio. Relevant obstetric information was retrieved from the antenatal records. The student t- test and Pearson's product moment were used for statistical analysis.Fifty eight (13.5%) out of 430 pregnancies had complications of impaired placentation, mainly intrauterine growth restriction and preterm birth (24 or 41.4% each). The indices in normal pregnancies were similar to presently used values. There was no statistically significant difference in the 2 pregnancies groups. The Pulsatility Index (PI) in the right uterine artery was statistically different from the left (t-test 32.8, p < 0.05). Maternal age and parity demonstrate statistically significant positive correlation with PI (r =0.9, p < 0.05; r =0.8, p < 0.05).The indices in normal pregnancies were similar to values from previous studies. The values are however not significantly different in pregnancies with abnormal outcome.
- Investigation of endothelial dysfunction and arterial stiffness in children with type 1 diabetes mellitus and the association with diastolic dysfunction. [Journal Article, Research Support, Non-U.S. Gov't]
- Diab Vasc Dis Res 2014 Jan; 11(1):19-25.
The objective of this study is to investigate endothelial dysfunction (ED) and arterial stiffness (AS) and determine the association with diastolic dysfunction in children with type 1 diabetes mellitus (DM).A total of 42 patients without diabetic complications (mean age: 13.21 years) and 40 healthy (mean age: 13.07 years) children were included in this study. AS was assessed with ascending aorta M-mode measurements, diastolic dysfunction with pulsed wave (PW) Doppler and tissue Doppler echocardiography measurements and flow-mediated dilatation (FMD) and carotid intima-media thickness (CIMT) with high-resolution ultrasonography.Results of diabetic group and healthy children were compared. In diabetic group, aortic strain (8.40 ± 2.98, 20.12 ± 5.04; p < 0.001), aortic distensibility (7.36 ± 2.92, 16.59 ± 4.25; p < 0.001) and FMD% (7.70 ± 2.83, 11.33 ± 2.85; p < 0.001) were found decreased, and CIMT (0.52 ± 0.09 mm, 0.47 ± 0.08 mm; p < 0.05) was found increased. Additionally, left ventricular lateral segment and right ventricular free-wall isovolumic relaxation time (IVRT) and myocardial performance index (MPI) were found increased. Correlation analyses demonstrated a negative correlation between FMD and IVRT and MPI.ED and AS were found in type 1 DM patients without diabetic complications. Additionally, correlation was shown between increased AS and ED and right and left ventricular diastolic dysfunctions.
- CLOTBUST-Hands Free: pilot safety study of a novel operator-independent ultrasound device in patients with acute ischemic stroke. [Clinical Trial, Phase II, Journal Article, Research Support, N.I.H., Extramural]
- Stroke 2013 Dec; 44(12):3376-81.
The Combined Lysis of Thrombus in Brain Ischemia With Transcranial Ultrasound and Systemic T-PA-Hands-Free (CLOTBUST-HF) study is a first-in-human, National Institutes of Health-sponsored, multicenter, open-label, pilot safety trial of tissue-type plasminogen activator (tPA) plus a novel operator-independent ultrasound device in patients with ischemic stroke caused by proximal intracranial occlusion.All patients received standard-dose intravenous tPA, and shortly after tPA bolus, the CLOTBUST-HF device delivered 2-hour therapeutic exposure to 2-MHz pulsed-wave ultrasound. Primary outcome was occurrence of symptomatic intracerebral hemorrhage. All patients underwent pretreatment and post-treatment transcranial Doppler ultrasound or CT angiography. National Institutes of Health Stroke Scale scores were collected at 2 hours and modified Rankin scale at 90 days.Summary characteristics of all 20 enrolled patients were 60% men, mean age of 63 (SD=14) years, and median National Institutes of Health Stroke Scale of 15. Sites of pretreatment occlusion were as follows: 14 of 20 (70%) middle cerebral artery, 3 of 20 (15%) terminal internal carotid artery, and 3 of 20 (15%) vertebral artery. The median (interquartile range) time to tPA at the beginning of sonothrombolysis was 22 (13.5-29.0) minutes. All patients tolerated the entire 2 hours of insonation, and none developed symptomatic intracerebral hemorrhage. No serious adverse events were related to the study device. Rates of 2-hour recanalization were as follows: 8 of 20 (40%; 95% confidence interval, 19%-64%) complete and 2 of 20 (10%; 95% confidence interval, 1%-32%) partial. Middle cerebral artery occlusions demonstrated the greatest complete recanalization rate: 8 of 14 (57%; 95% confidence interval, 29%-82%). At 90 days, 5 of 20 (25%, 95% confidence interval, 7%-49) patients had a modified Rankin scale of 0 to 1.Sonothrombolysis using a novel, operator-independent device, in combination with systemic tPA, seems safe, and recanalization rates warrant evaluation in a phase III efficacy trial.http://www.clinicaltrials.gov. Unique identifier: CLOTBUST-HF NCT01240356.