OBJECTIVE: Cardiac defects are the most prevalent congenital anomalies. Screening policies have adopted an 18- to 22-week ultrasound scan to detect such anomalies. However, diagnosis may be feasible early in pregnancy using transvaginal Doppler ultrasound. METHODS: Transvaginal ultrasound, including nuchal translucency (NT) measurement, is routinely performed at 10-13 weeks of ...

We applied frequency domain analysis to detect and quantify spontaneous fluctuations in the blood flow velocity of the middle cerebral artery (MCAFV). Instantaneous MCAFV of normal volunteers was detected using transcranial Doppler sonography. Spectral and transfer function analyses of MCAFV and arterial blood pressure (ABP) were performed by fast Fourier ...

PURPOSE: To determine if power Doppler sonography allows differentiation of infectious from noninfectious hip effusions and thereby obviates joint aspiration. MATERIALS AND METHODS: Twenty-nine consecutive children (30 hips) with sonographically identified hip effusion were prospectively evaluated with power Doppler sonography. Both hips were evaluated in each patient by using identical ...

Ultrasonic Doppler methods are routinely used to study the vascular system. Flow and tissue motion information can be obtained by frequency and time domain processing. Instruments range in complexity from simple continuous wave devices without imaging capability through to advanced real-time 2D colour flow scanners and intravascular devices. 3D display ...

OBJECTIVE: The objective of this study was to characterize the Doppler waveform in the cartilaginous capital femoral epiphysis of healthy neonates with the aid of power Doppler and duplex Doppler imaging. SUBJECTS AND METHODS: In this prospective study, both hips were examined in 63 neonates. We used conventional sonographic imaging ...

The history of Doppler ultrasound in peripheral vascular diagnosis is considered in terms of basic developments, clinical applications and impact on medical practice. Many early developments occurred at Osaka University in Japan and the University of Washington in the United States. Through progressive steps, Doppler ultrasound technology has provided clinical ...

OBJECTIVE: To measure blood flow in the palmar digital artery and laminae corium, using ultrasonic and laser Doppler flowmetry, respectively. ANIMALS: 6 healthy horses. PROCEDURE: Digital blood flow and laminar perfusion, respectively, were measured by placing a flow probe around the palmar digital artery and a laser Doppler flow probe ...

This study evaluates physiological fluid heating during continuous bilateral insonation at 530 mW/cm2 for 8 h in a bench simulation. It also examines the physiologic, histopathologic, and neurologic effects of bilateral Doppler imaging of middle cerebral artery (MCA) blood flow velocity using ultrasonic beams with 530 mW/cm2 intensity in a ...

The choice of the optimal ultrasonic frequency for vascular studies is determined by the required resolution and penetration. Anatomical real-time two-dimensional imaging and blood flow studies provide complementary information. Intravascular scanning allows high-frequency ultrasound to be used, with correspondingly good spatial resolution. Contrast resolution is degraded by beam side lobes ...

Power Doppler sonography (PD) is a technique that displays the strength of the Doppler signal, rather than the flow velocity and directional information. Its increased flow sensitivity and better vascular delineation have been used to document the presence and characteristics of flow in vessels that are poorly imaged with conventional ...

BACKGROUND: This study tested a prototype laser Doppler scanner for the measurement of human colonic blood flow. METHODS: Blood flow distribution was assessed in human colon during operation in six controls and in six patients with inflammatory bowel disease undergoing colectomy. Image processing software analysed several hundred reading points, expressing ...

The ability to measure the velocity of blood flow independent of the orientation of the blood vessel could aid in evaluation of many disease processes, such as coronary lesions. Conventional ultrasonic Doppler techniques require knowledge of the beam-to-flow angle, and the Doppler effect vanishes when this angle is 90 degrees ...

It has recently been observed using power Doppler that cerebral aneurysms appear to change size through the cardiac cycle. The purpose of this study was to develop a pulsatile flow model of cerebral aneurysm expansion and to investigate whether the observations of pulsation could be confirmed using the model. The ...

A noninvasive optical technique has been developed for imaging in vivo blood flow dynamics and vessel structure with high spatial resolution. The technique is based on optical Doppler tomography, which combines Doppler velocimetry with optical coherence tomography to measure blood flow velocity at discrete spatial locations in turbid biological tissue. ...

The nitric oxide (NO) donor sodium nitropruside (SNP) applied to the round window membrane has recently been found to increase cochlear blood flow (CoBF) in normal guinea pigs and in normal and presbyacusic mice. This study examined the effect of topical applications of SNP on experimentally impaired CoBF in anesthetized ...

Dynamic changes of perilymphatic glutamate and cochlear blood flow were measured simultaneously in the guinea pig following cochlear ischemia. Glutamate was measured by the microdialysis technique with a probe inserted into the scala tympani at the basal turn. Cochlear blood flow was monitored with a laser-Doppler probe on the lateral ...

PURPOSE: To normalize the power Doppler ultrasound (US) signal to the expected signal from 100% blood in the calculation of a fractional moving blood volume estimate. MATERIALS AND METHODS: To locate the signal from flowing blood with a consistent backscatter coefficient, the authors estimated the knee of the cumulative Doppler ...

A method is suggested for quantitative flow assessment of whole-blood perfusing tubes with diameters in the range from 500 microns to 1.5 mm, for velocities below 9 mm s-1. The algorithm is based both on the Doppler broadening of backscattered laser light and the magnitude of the diameter of the ...

This study quantified changes in blood flow following tooth brushing, using laser Doppler flowmetry (LDF). Twenty subjects had polysiloxane stents fabricated with openings to permit placement of the LDF probe on the mesial papillae of 6 teeth. Probing depth, plaque index, and gingival index were recorded and subjects instructed in ...

PROBLEM: A rapid, accurate, noninvasive method of determining pulpal blood flow would be helpful in determining pulpal vitality. OBJECTIVE: The purpose of this study was to determine if laser Doppler flowmetry can measure induced changes in pulpal blood flow. STUDY DESIGN: Two percent lidocaine with epinephrine 1:100,000 was infiltrated into ...

Ultrasound Doppler has been used to measure arterial inflow to a human limb during intermittent static contractions. The technique, however, has neither been thoroughly validated nor used during dynamic exercise. In this study, the inherent problems of the technique have been addressed, and the accuracy was improved by storing the ...

Use of new scanning approaches, such as the mastoid fontanelle and new signal processing techniques, such as power Doppler and spectral Doppler during fontanelle compression, have dramatically improved our ability to image both the structure and hemodynamics of blood flow in the neonatal brain. Continuing development of US contrast agents ...

Recent years have seen the introduction of a high quality imaging modality which uses the Doppler shift for the study of blood flow and tissue motion. Colour ultrasound technology has now reached a level of maturity and it is, therefore, timely to review its features and consider how colour techniques ...

Intraobserver and interobserver reproducibility of transvaginal Doppler velocimetry measurements in uterine arteries were assessed by two observers in 20 postmenopausal women. In addition, the agreement between the observers regarding the detection of an ovary as well as the presence or absence of intraovarian arterial blood flow was documented. Pulsatility index ...

Functional transcranial Doppler sonography (fTCD) is used to measure changes in brain perfusion during different states of brain activity by evaluating flow velocities within the major brain arteries. We developed a computer program called AVERAGE which can be used with various TCD devices and allows for subtle quantitative off-line analysis ...

We report the development of an optical technique for noninvasive imaging of in vivo blood flow dynamics and tissue structures with high spatial resolution (2-10 microm) in biological systems. The technique is based on optical Doppler tomography (ODT), which combines Doppler velocimetry with optical coherence tomography to measure blood flow ...

The estimation of blood flow in arteries is important in the study of the (patho)physiology of the circulatory system. However, non-invasive techniques using pulsed Doppler ultrasound have so far shown potentially large errors. The aim of this study was to evaluate the precision and variability of a newly developed non-invasive ...

OBJECTIVE: To obtain Doppler ultrasonographic images of renal arteries in horses and to establish reference range values for systolic and diastolic renal arterial blood flow and resistive indices. Also to determine whether Doppler ultrasonography could be used in horses to detect changes in renal blood flow after IV administration of ...

A new laser Doppler perfusion imaging (LDI) system was evaluated by comparing it with the well-established radiolabelled microsphere technique for measuring blood flow in the rabbit knee joint capsule. In this study two laser sources (635 and 835 nm) were compared at three scan speeds (50, 10 and 4 ms/pixel). ...

An in vivo investigation was conducted to assess the ability of two laser Doppler flowmeters (DRT4, Moor Instruments Ltd; Laserflo BPM2, Vasamedics) to differentiate between vital pulp, ischaemically necrosed pulp, and an empty pulp chamber in premolar teeth in children. Sixteen intact, vital teeth in need of extraction for orthodontic ...

The process of placentation in the macaque has been extensively studied and found to resemble closely that observed in the human. In this model, histopathologically, intervillous flow is anticipated from week 3 post-conception. We set out to document the nature and onset of intervillous flow in the macaque in vivo ...

The purpose of this study was to determine whether use of transmitted laser light would enable a better assessment of human pulpal vitality than back-scattered light does (LDF: laser Doppler flowmetry). The experiments were carried out on ten upper central incisors in six subjects aged 23-28 years; five of the ...

Small gas bubbles have been used as ultrasound signal enhancers for many years. However, only recently have microbubble preparations become available that provide useful and reproducible enhancement on ultrasound scans after i.v. administration. Levovist is a galactose/palmitic acid-based agent that, on dissolution and agitation in sterile water, generates air-filled microbubbles ...

RATIONALE AND OBJECTIVES: Based on the echo-enhancing effect of microbubbles, various agents have been developed to improve the diagnostic confidence in patients with inadequate Doppler signals. In the clinical trials of the echo enhancer Levovist, there were a few isolated cases in which the maximum flow velocities of the enhanced ...

Changes in dorsal cochlear nucleus (DCN) blood flow during noise exposure were assessed using both intravital microscopy (IVM) and laser Doppler flowmetry (LDF). Mature Syrian golden hamsters were anesthetized, tracheotomized and implanted with a carotid artery catheter for monitoring blood pressure and infusion of fluorescent dye. An occipital craniectomy was ...

The application of Doppler-tipped guide wires to measure blood flow velocity in coronary and peripheral arteries has been described previously as a valuable means of functional assessment in interventional cardiological procedures. In animal studies intravascular Doppler has been used in the cerebrovascular system, and this appears to be an important ...

PURPOSE: To evaluate the feasibility of direct intravascular determination of renal artery (RA) blood flow with a Doppler probetipped guide wire. MATERIALS AND METHODS: Potential renal donors (n = 10) with normal RAs (n = 23) underwent evaluation of RA blood flow velocity with use of a 0.018-inch, 12-MHz Doppler ...

Using Doppler ultrasound, we prospectively evaluated the relationship between central venous blood flow and the development of central venous thrombosis in ten patients with a long term central line. The presence of turbulent blood flow around the catheter was followed by the development of central venous thrombosis in two patients ...

This study evaluates local variations of the cerebral vasomotor responses to hypercapnia and haemorrhagic hypotension in a pig model. Four laser Doppler flow probes were used in each pig. There was considerable variation in laser Doppler signals between the four probes in baseline recordings. The increases in flow after CO2 ...

An experimental system has been developed to verify the possibility of detecting flow activity using a technique called ultrasound Doppler vector tomography. A tomography algorithm is used to reconstruct blood flow vector fields using data from computer-controlled ultrasound continuous-wave Doppler scanning equipment. The result is a picture in which the ...

PURPOSE: To evaluate the in vitro sensitivity for the detection of slow blood flow in tiny tubes with an amplitude Doppler ultrasound (US) technique at different angles and pulse repetition frequencies. MATERIALS AND METHODS: Human blood treated with heparin was pumped through silicone tubes (flow phantoms made by the author) ...

Pulsed Doppler spectral analysis is a well-established diagnostic technique in the assessment of arterial diseases. Because of hardware limitations, its use has been so far restricted to the analysis of a single sample volume located along the ultrasound beam axis. In this paper, we discuss the operation of a newly ...

The objective of the present work was to design Doppler sensors and harnesses for monitoring in real time the cardiac stroke volume and output, the cerebral flow volume and resistance and the lower limb arterial flow and resistance changes. For the middle cerebral artery investigation we used a 2-MHz transcranial ...

Transcutaneous oximetry, laser Doppler flowmetry and ankle brachial systolic pressure indices were used to investigate blood flow to the feet in 26 subjects with diabetes mellitus and peripheral arterial disease. A total of 21 critically ischaemic feet and 15 non-critically ischaemic feet were investigated. Using laser Doppler flowmetry, non-critically ischaemic ...

Intraurethral instillation was used in place of intracavernosal injection of vasoactive agents for the colour Doppler investigation of patients with erectile dysfunction. A total of 19 patients were enrolled in this study. Colour penile Doppler ultrasonography was done with intracavernosal injection of papaverine-HCl 60 mg and intraurethral instillation of prostaglandin-E2 ...

Power Doppler imaging was performed in 77 patients with lower urinary tract symptoms to characterize Doppler blood-flow signals in benign prostatic hyperplasia (BPH). Pulsatile blood flows were detected in all patients, demonstrating a significant increase of the resistive index (RI) in BPH cases (n = 40, 0.72 +/- 0.05, p ...

A novel application of laser Doppler flowmetry (LDF) laser Doppler perfusion imaging (LDPI), was used to study cerebral cortical blood flow (CBFcortex). In contrast to the conventional laser Doppler perfusion monitor, LDPI creates two dimensional maps of the tissue perfusion in a well defined area of up to 120 x ...

Blood flow information available from transcranial Doppler ultrasound is usually derived from velocity alone because no knowledge of vessel caliber is available. In cases such as vasospasm, where vessel size changes, the inference of flow from velocity becomes questionable. A computational technique was used to calculate a flow index and ...

This study investigated the vascular effect of ferromagnetic obstruction of cochlear blood vessels in the guinea pig using dual-channel laser Doppler flowmetry. To improve this technique, we tested new types of magnets and iron spheres. In so doing, the cochlear temperature was lowered selectively and general hypothermia was avoided. The ...

The acute effects of beraprost sodium (sodium (+/-)-(1R*, 2R, 3aS*, 8bS*)-2, 3, 3a 8b-tetrahydro-2-hydroxy-1-[(E)-(3S*)-3-hydroxy-4-methyl-I- octen-6-ynyl] -1H-cyclopenta [b] bensofuran-5-butyrate), a stable analogue of prostaglandin I2 which works as a vasodilator and anti-platelet agent, were investigated in patients with non-insulin dependent diabetes mellitus. Its effects on the dorsal pedis artery were examined ...