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At least 19 recordsLinked to original sources
PubMed1995

Fetal pressure gradient estimations across the ductus venosus in early pregnancy using Doppler ultrasonography.

Doppler ultrasonography was used to estimate the pressure gradient across the ductus venosus at 8-20 weeks of gestation. According to a cross-sectional study design, flow velocity waveform recordings were obtained from the umbilical vein and ductus venosus in 147 uncomplicated singleton pregnancies. Pressure gradients were calculated using the Bernoulli equation. The pressure gradient was estimated at 0.1-1.9 mmHg during ventricular systole and at 0-0.5 mmHg during atrial contraction. Time-averaged pressure gradients ranged between 0.1 and 1.3 mmHg. No statistically significant correlation could be established between the absence or presence of umbilical venous pulsations and estimated pressure gradient. Crude estimates of the pressure gradient across the ductus venosus can be established in the late first and early second trimester of pregnancy. The large scatter of data suggests limited accuracy of venous pressure gradient calculation in early gestation. However, it may also indicate that, in early gestation, venous hemodynamics function at very low pressures.

Adult↗
PubMed2006

Evaluation of nonunion fractures in dogs by use of B-mode ultrasonography, power Doppler ultrasonography, radiography, and histologic examination.

OBJECTIVE: To investigate the use of ultrasonography to assess nonunion of fractures in dogs and to compare results of ultrasonography, radiography, and histologic examination. SAMPLE POPULATION: 8 nonunion fractures in 6 dogs (1 each in 5 dogs and 3 in 1 dog); dogs ranged from 7 to 94 months of age and weighed 6 to 30 kg. PROCEDURES: Diagnostic assessment consisted of complete clinical and orthopedic examinations, radiography, B-mode (brightness mode) ultrasonography, and power Doppler ultrasonography. Biopsy samples were obtained during surgery for histologic examination. They were stained with H&E and immunolabeled by use of anti-CD31 antibodies. Correlations of power Doppler score, power Doppler count, vessel area, and radiographic prediction with the mean number of vessels counted per hpf were derived. RESULTS: Radiographically, 7 of 8 nonunion fractures were diagnosed as atrophic and were therefore estimated to be nonviable. Vascularity of nonunion fractures during power Doppler ultrasonography ranged from nonvascularized to highly vascularized. Absolute vessel count during histologic examination ranged from 0 to 63 vessels/hpf; 5 nonunion sites had a mean count of > 10 vessels/hpf. Vascularity during power Doppler ultrasonography was highly correlated with the number of vessels per hpf, whereas the correlation between the radiographic assessment and histologic evaluation was low. CONCLUSIONS AND CLINICAL RELEVANCE: Radiographic prediction of the viability of nonunion fractures underestimated the histologically assessed vascularity of the tissue. Power Doppler ultrasonography provided a more accurate estimation of the viability of the tissue and therefore the necessity for debridement and autografts during revision surgery.

Animals↗
PubMed1989

Emergency department use of hand-held Doppler ultrasonography.

Doppler ultrasonography (DU) using a hand-held Doppler device represents a readily available emergency department (ED) technique that has been used for diagnostic testing with conditions associated with abnormal vascular flow, such as deep venous thrombosis, testicular torsion, and arterial insufficiency. DU may serve as a useful initial diagnostic test in the ED setting. The appropriate indications, techniques of examination, and accuracy of DU are summarized for the aforementioned conditions.

Emergencies↗
PubMed1986

Non-invasive grading of aortic regurgitation by Doppler ultrasonography.

Doppler ultrasound without concomitant echocardiographic imaging was used to grade isolated aortic regurgitation in 21 patients. The severity of aortic regurgitation was subsequently graded (from 0 to IV) angiographically. A 2 MHz continuous wave Doppler transducer was placed over the apex of the heart and the beam was aimed parallel to the mitral flow by means of acoustic guidance. Mitral pressure half time was calculated from the analogue maximum velocity tracing and it was less than or equal to 60 ms in 10 controls; 50-120 ms in five patients with grade II, 120-160 ms in nine patients with grade III, and greater than or equal to 160 ms in seven patients with grade IV aortic regurgitation. These results indicate that a semi-quantitative grading of aortic regurgitation may be obtained non-invasively with non-imaging Doppler ultrasonography in patients without concomitant mitral valve disease.

Adult↗
PubMed1990

Progressive functional deterioration of bioprostheses assessed by Doppler ultrasonography.

Doppler echocardiography was used to study the function of bioprosthetic heart valves by noninvasive means in 32 patients aged 29 to 72 years at various postoperative intervals. There were 24 Ionescu-Shiley, four Hancock, and four Carpentier-Edwards prostheses, 19 in the aortic and 13 in the mitral position. Initial studies were performed at a mean of 2.3 years after implantation and were repeated one, two, and three years thereafter. Flow velocities in the mitral orifice, left ventricular outflow tract, and ascending aorta, as well as mitral pressure half-time, were measured from pulsed-wave or continuous-wave Doppler recordings. Mitral and aortic valve areas and aortic pressure gradients were calculated. In aortic prostheses the valve area decreased and pressure gradient increased progressively in relation to the time from implantation. The mean value (+/- SD) of the aortic valve area was 67 +/- 17 percent of the manufacturer's nominal value at the first examination and 57 +/- 20 percent one year later, 51 +/- 14 percent two years later, and 46 +/- 11 percent three years later (overall differences, p less than 0.01). In mitral prostheses, reduction of the valve area was not related to the time from implantation. The mean mitral valve area was 45 +/- 12 percent of the nominal value at rest and increased to 68 +/- 18 percent during exercise at a mean of 45 months after implantation. There was no change in these values at the one-year repeat study. It is concluded that in a population with predominantly pericardial bioprostheses, (1) aortic tissue prostheses showed a progressive functional deterioration demonstrable by Doppler echocardiography, most probably due to degenerative changes; and (2) in mitral tissue prostheses, there was no significant reduction of orifice area in relation to time from implantation. Reduction of mitral valve areas may, to some extent, reflect a less than full opening at rest.

Aortic Valve↗
PubMed1997

Acute effects of thromboxane dual blocker (KDI-792) on different portions of lower limb blood flow--a study using Doppler ultrasonography and laser Doppler flowmetry in type 2 diabetic patients.

The acute effects of a newly synthesized thromboxane dual blocker (KDI-792), a combined thromboxane synthase inhibitor and receptor antagonist, on lower limb circulation were examined using two-dimensional color and pulse Doppler ultrasonography and laser Doppler flowmetry. A randomized single-masked, placebo-controlled trial was performed on 36 type 2 diabetic patients with minimally impaired baseline flow. The anatomical cross-sectional area (CSA), maximum flow velocity (MFV) and flow volume index (FVI) in the right dorsal pedis artery (DPA) and right femoral artery (FA) were determined by Doppler ultrasonography before and 45 and 90 minutes after the administration of either 100 or 200 mg of KDI-792 to the dose groups or placebo to the control group. Periflux blood flow (PBF) in the right foot was determined simultaneously by laser Doppler flowmetry. Both CSA and MFV in the dose groups were significantly increased in both the FA and DPA. FVI was markedly increased from 21.4 +/- 3.7 to 68.3 +/- 26.8 in the DPA (M +/- SD, P < 0.01) and from 365.4 +/- 35.3 to 771.7 +/- 75.7 in the FA (P < 0.01) in the 200 mg dose group. In the 100 mg dose group, FVI was markedly increased from 20.0 +/- 8.7 to 68.3 +/- 26.8 (P < 0.01) in the DPA and from 372.5 +/- 130.0 to 677.5 +/- 187.8 (P < 0.01) in the FA. PBF was also increased in both dose groups (from 4.15 +/- 1.4 to 7.0 +/- 4.0 ml/min/100 g tissue in the 200 mg dose group, P < 0.01), whereas there were no significant changes in either measurement in the control group. There were no significant changes in pulse rate or blood pressure after administration in either the dosage group or the placebo group. These and previous findings indicate that a single administration of KDI-792 markedly increases lower limb blood flow and might have a more potent vasodilating effect than that of prostaglandin I2 derivatives.

Aged↗
PubMed1999

[Diagnosis of thyroid nodules by Doppler ultrasonography: a comparison between color Doppler and power Doppler ultrasonography].

The purpose of this study was to assess the usefulness of color and power Doppler imaging in thyroid nodules. The following 4 items were compared between malignant thyroid nodules (34 cases) and benign nodules (51 cases): 1) vascularity; 2) distribution of tumor vessels (none, marginal, peripheral, central); 3) nature of tumor vessels (tortuosity, interruption); and 4) FFT analysis. The distribution of tumor vessels on color Doppler images, nature of tumor vessels on power Doppler images, and the indices of PI, RI, and ATI in FFT analysis were useful in making the differential diagnosis between malignant and benign nodules. In terms of vascularity, including the distribution of tumor vessels on power Doppler images and nature of tumor vessels on color Doppler images, no statistically significant differences were found between malignant and benign nodules. Power Doppler images depicted tumor vessels in more detail than color Doppler images and were considered to extend the application of FFT analysis.

Diagnosis, Differential↗
PubMed1995

Efficacy of Ibudilast on lower limb circulation of diabetic patients with minimally impaired baseline flow: a study using color Doppler ultrasonography and laser Doppler flowmetry.

Ibudilast is a prostacyclin-mediated vasodilator and antiplatelet agent. The hemodynamic effects of ibudilast were evaluated in 41 patients with non-insulin-dependent diabetes mellitus by means of two-dimensional Doppler ultrasonography and laser Doppler blood flowmetry. Before and one hour after oral administration of ibudilast (10 mg), or elastase (1800 U) as a control, the cross-sectional area (CSA) of the dorsal pedis artery, its blood flow index (BFI), and dermal microcirculatory blood volume (MBV) were measured. In the ibudilast group, all of the parameters (CSA, BFI, and MBV) significantly increased as compared with the elastase group. These data suggest that ibudilast is effective in ameliorating diabetic macroangiopathy and microangiopathy of the lower limbs.

Administration, Oral↗
PubMed1999

Limitations of characterization of hepatic hemangiomas using a sonographic contrast agent (Levovist) and power Doppler ultrasonography.

Power Doppler ultrasonography using a sonographic contrast agent (Levovist) was evaluated in 20 patients with hepatic hemangiomas with a 2-4 MHz convex transducer according to a standardized examination protocol (pulse repetition frequency, 1000 Hz; medium wall filter; power Doppler gain, 50 to 85%). Enhancement patterns were assessed and were compared with those on dynamic magnetic resonance imaging (n = 11) or computed tomography (n = 9). The most common enhancement pattern was dotlike or linear enhancement located predominantly at the periphery of the tumor (15 cases, 75%). Diffuse homogeneous enhancement was seen in one case (5%). No definite contrast enhancement was evident in four cases (20%). The enhanced area on ultrasonograms was smaller than that on dynamic MR images or CT scans in 18 cases (90%). A transient centripetal fill-in pattern was identified in six cases (30%). Persistent enhancement until 300 s was not seen in any case. Therefore, specific diagnosis of hemangioma with power Doppler ultrasonography and contrast agent may not be possible.

Adult↗
PubMed1995

Blood flow in free muscle flaps measured by color Doppler ultrasonography.

Color Doppler ultrasonography, a noninvasive method for studying changes in blood flow, has been used to monitor 18 patients with free microvascular lower limb muscle flaps. The peak, mean, and minimum velocities, resistance indices, and diameters of the flap pedicle arteries and also of the limb recipient arteries proximal to the microvascular anastomoses were measured at 2 and 6 weeks and 3, 6, and 9 months after surgery. The peak velocities did not significantly differ from each other, but the mean velocity in the flap pedicle arteries was 12.5% higher than that in the recipient arteries throughout the study period. End diastolic velocity in the pedicle was positive (toward the ultrasound probe) at 2 weeks (mean, 2 cm/sec, SD 10), 6 weeks (mean, 5 cm/sec, SD 16), and 3 months (mean, 3 cm/sec, SD 13) after surgery and significantly higher (P < 0.05) than at 6 months (mean, 7 cm/sec, SD 11), when the pattern of blood flow was normal forward/backward flow during systole/diastole. The resistance indices of the pedicle at 2 weeks (Ri = 0.978), 6 weeks (Ri = 0.936), and 3 months (Ri = 1.001) were significantly lower (P < 0.05) than at 6 months (Ri = 1.108), when the pedicle and recipient artery indices were the same. The diameter of the pedicle arteries was 14% smaller than those of the recipient arteries, but did not change during follow-up. This prospective clinical study shows that blood flow in the pedicle of a free microvascular muscle flap is increased until 6 months after surgery, mainly due to the increased minimum velocity of the pedicle in diastole and decreased resistance index. These findings can be attributed to the loss of vessel tone after denervation and are in accordance with earlier studies showing that denervated muscles lose their autoregulation and that blood flow increases, but that these phenomena subside with time. Increased blood flow in free muscle flaps can explain the high success rate of microanastomoses and positive effect on wound healing.

Adult↗
PubMed1997

Detection of tumor thrombus in children using color Doppler ultrasonography.

Color Doppler ultrasonography (CDUS), which provides information regarding both the tissue and the blood flow simultaneously in real time, is a relatively new and noninvasive technique for the evaluation of organ perfusion. The authors investigated the usefulness of CDUS in the detection of tumor thrombus in 34 children who had malignant tumor (21 neuroblastomas, 2 Wilms' tumors, 5 hepatoblastomas, 2 rhabdomyosarcomas, and 4 others) who underwent CDUS between April 1992 and March 1995 in our department. The CDUS showed tumor thrombus in four patients (11.8%). Three thrombi (in one patient each with neuroblastoma, Wilms' tumor, and hepatoblastoma) were situated in the inferior vena cava, and one (in a patient who had hepatoblastoma) in the portal vein. Each tumor thrombus was monitored and followed up using CDUS every month during the entire clinical course; two of the four thrombi remained despite intensive treatments. The authors have found CDUS to afford rapid and noninvasive detection of tumor thrombus, and it proved useful not only in the detection of tumor thrombus but also in its follow-up in these children who had malignant tumor.

Child, Preschool↗
PubMed1999

The comparison between the cerebral blood flow directly measures and cerebral blood flow velocity in the middle and basilar cerebral arteries measured by transcranial Doppler ultrasonography.

Transcranial Doppler ultrasonography (TCD) may be useful for determining alterations in cerebral blood flow (CBF) during excessive hemodynamic changes by non-invasive measurement of the CBF velocity. The purpose of this study was to measure the correlation between CBF and the middle cerebral artery (MCA) and basilar artery (BA) flow velocities, as measured by TCD during excessive hemodynamic changes produced by hypertension and hypotension in adult dogs. The peak, diastolic, and mean flow velocities were measured by TCD. Arterial hypertension was induced by administration of dopamine at 5 and 15 microg/kg/min, and hypotension was induced by hemorrhage. During the hemodynamic changes, the BA velocity correlated more closely with the alteration in the CBF than the MCA velocity. In terms of percentages of the values during anesthesia, there was good correlation between CBF and the MCA and BA velocities. In conclusion, our findings indicate that MCA and BA velocity measurements, as a percentage of the values during anesthesia, both give an equally accurate indication of alterations in CBF during excessive hemodynamic changes.

Animals↗
PubMed1994

Transcranial Doppler ultrasonography.

Transcranial Doppler ultrasonography is an extremely useful adjunct in neurosurgical intensive care. Continuous improvements in TCD equipment as well as computer software have improved examination success and also vessel identification. Recent expanding applications of TCD have also allowed the study of disorders of control of the cerebral circulation. TCD can be used to detect vessel narrowing from a variety of causes, including vasospasm, and also can be used to detect cerebral emboli and to evaluate CO2 reactivity, autoregulation, and the response to certain medications, as well as to indicate progressive obstruction of the cerebral circulation as seen in conditions leading to brain death. In the future, TCD may offer the ability to estimate the ICP using noninvasive means by evaluating velocity in the middle cerebral artery and arterial blood pressure tracings. The noninvasive determination of cerebral autoregulation may be useful in evaluating strategies to improve cerebral autoregulation as well as aid in the optimal management of ICP control and preservation of optimal cerebral circulation.

Blood Flow Velocity↗
PubMed2004

Prediction of renal allograft function with early Doppler ultrasonography.

INTRODUCTION: Doppler ultrasonography (USG) is an useful, noninvasive diagnostic tool for the management and follow-up of the transplanted kidney. However, it is believed that the value of Doppler USG is limited to discrimination of acute rejection episodes. We tested whether early Doppler USG findings were predictive of 1-month and 1-year allograft functions in noncomplicated renal transplant recipients (RTRs). PATIENTS AND METHODS: Resistive index (RI) and pulsatile index (PI) values obtained by doppler USG within the first week of transplantation were correlated with allograft function at 1 month and 1 year in 45 (10 women, 35 men, mean age: 27 years) noncomplicated cases. Patients with complications during the first posttransplant year were not included. RESULTS: There was a negative correlation between both RI and PI with creatinine clearance values at 1 month and at 1 year posttransplant. There was a significant decline in allograft function among cases with either RI > or = 0.7 or PI > or = 1.1. Patients with impaired allograft function have higher RI and PI values. CONCLUSION: Renal allograft survival is influenced by many factors. However, no reliable simple parameter has been identified to predict long-term outcome. Doppler USG performed during the early transplantation period with calculation of RI and PI may have a predictive value to forecast early and long-term outcomes of noncomplicated kidney transplants.

Adult↗
PubMed1994

[Comparison of the results of conventional ultrasonography and color doppler analysis in the evaluation of the nature of adnexal tumors. II. Color duplex doppler ultrasonography].

The author evaluates the possibilities of coloured Doppler vaginosonography for prebioptic evaluation of the nature of ovarian tumours. He investigated the site of vascularization of tumours and qualitatively the blood flow by assessing the vascular resistance (PI, RI) and character of the flow velocity curve. The results revealed a statistically significant (p < or = 0.05) trend of central vascularization of malignant tumours. A new parameter with a 100% sensitivity and 89% specificity proved to be the notch at the beginning of the diastolic part of the velocity curve which was not observed in any carcinomas but was present in 89% of benign lesions. The vascular resistance was significantly lower in malignant tumours. The cut off value of malignity of the pulsatility index PI = 0.7 had a 86% sensitivity and 100% specificity. The cut off value of the resistance index RI is 0.6 with a 100% sensitivity and 75% specificity. Comparison of the predictive values of malignity of conventional and coloured duplex ultrasonography revealed that for evaluation of the nature of ovarian tumours coloured duplex sonography with several parameters is more suitable. PI and RI alone can be considered rather as indicators of active growth.

Adult↗
PubMed2002

Pediatric abdominal applications of color Doppler ultrasonography.

Color Doppler ultrasonography (US) is a valuable imaging method because of the important information it provides with respect to organ perfusion, vessel patency, and tumor characterization. In addition, it is a noninvasive technique that does not use ionizing radiation. This review summarizes current applications of color Doppler US in the diagnosis of diseases or abnormalities of the liver and biliary tree, the urinary and gastrointestinal tracts, and the inguinal region.

Journal Article↗
PubMed1996

Intraoperative use of transcranial Doppler ultrasonography.

Transcranial Doppler (TCD) ultrasonography is a diagnostic tool that is well established in the fields of neurology and neurosurgery. There are many potential applications of TCD ultrasonographic monitoring in the perioperative care of the patient at risk of cerebral ischemia, the most important of which are detailed in this article. The introduction of TCD ultrasonography has made it possible to monitor intraoperative CBF changes in a continuous, noninvasive manner. Further refinement in the technology will delineate its appropriate use as an intraoperative monitor.

Brain Ischemia↗