985 resultados para Ultrasonography, doppler
Accuracy of doppler ultrasonography in the evaluation of hemodialysis arteriovenous fistula maturity
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This paper aims to describe the uterine and ovarian ultrasonographic characteristics and Doppler velocimetric features of their arteries in bitches during the periovulatory period. Fifteen estrous cycles in 10 animals were evaluated. The ultrasonographic characteristics, resistance indices (RI) and pulsatility indices (PI) of the uterus and ovaries in each animal were recorded 5 days before and after ovulation (D0). The data were statistically analyzed, and the results were expressed as the mean ± standard error of mean (P<0.05). In results the ultrasonographic features of the uterus were the same on all of the cycles and evaluated days. The uterus had an average diameter of 0.85±0.02cm. An increase in the volume of the ovaries and the diameter of the ovarian follicles were measured. Ovaries had a volume of 0.64±0.06cm³, and the follicles cavities had a diameter of 0.46 ± 0.01 cm on the day of ovulation. After ovulation, it was observed that some follicles not collapse in some cycles. Two days prior to ovulation, the uterine blood perfusion decreased. This decrease remained unchanged until ovulation. Following ovulation, we measured a gradual increase in the uterine perfusion and in the ovarian artery. This artery directed blood flow to the ovaries and increased the intra-ovarian perfusion on the day after ovulation. In conclusion, specific features are observed in the uterus and ovarian ultrasound image and Doppler values of their arteries presented on the periovulatory days and when associated allow to estimate more accurately the date of ovulation.
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Abstract: Annually hundreds of crab-eating foxes (Cerdocyon thous) are referred to rehabilitation centers and zoos in Brazil. The ultrasonographic study of wildlife species is an important tool for a non-invasive and accurate anatomical description and provides important information for wildlife veterinary care. The aim of the present study was to determine the characteristics of the main abdominal organs as well as the vascular indexes of the abdominal aorta and renal arteries of crab-eating foxes (Cerdocyon thous) using mode B ultrasonography and Doppler ultrasonography, respectively. Ultrasonographic features of the main abdominal organs were described and slight differences were noticed between ultrasound imaging of abdominal organs of crab-eating foxes and other species. The bladder presented wall thickness of 12±0.01mm, with three defined layers. Both, the right and left kidneys presented corticomedullary ratio of 1:1 and similarly to the adrenals and the liver, they were homogeneous and hypoechoic compared to the spleen. The spleen was homogeneous and hyperechoic compared to the kidneys. The stomach presented 3 to 5 peristaltic movements per minute, wall thickness of 39±0.05mm and lumen and mucosa with hyperechoic and hypoechoic features, respectively. Small and large intestines presented 2 to 3 peristaltic movements per minute, wall thickness of 34±0.03mm and three defined layers with hyperechogenic (submucosa and serosa) and hypoechogenic (muscular) features. Ovaries of the female crab-eating fox were hypoechoic compared to the spleen and with heterogeneous parenchyma due to the presence of 2x2mm ovarian follicles. Prostates of the six males were regular and with a well defined boundary, with a homogeneous and hyperechoic parenchyma compared to the spleen. Vascular indexes of the abdominal aorta (PSV: 25.60±0.32cm/s; EDV: 6.96±1.68cm/s; PI: 1.15±0.07 e RI: 0.73±0.07) and right (PSV: 23.08±3.34cm/s; EDV: 9.33±2.36cm/s; PI: 1.01±0.65 e RI: 0.65±0.16) and left renal arteries (PSV: 23.74±3.94cm/s; EDV: 9.07±3.02cm/s; PI: 1.04±0.31 e RI: 0.64±0.10) were determined. Thus, conventional and Doppler ultrasonographic imaging provides basic information that can be used as reference for the species as well for other wild canids and it is a precise and non-invasive method that can be safely used to evaluate and diagnose abdominal injuries in these patients.
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Objectives: This study aimed to evaluate the characteristics of the brain and vascular indicesof the middle cerebral artery of canine foetuses. Methods: Twenty-five bitches were selected. Tissue development, echogenicity, echotexture and brain echobiometric data were studied, and the major structures were identified between the 5th and 8th gestational weeks. The area and volume of the brain mass (BMA and BMV), cranial area and volume (AC and VC), brain mass index (BMI) and brain volume index (BVI) were determined. A single ultrasound examination was performed during each studied week (6th, 7th and 8th). Doppler ultrasonography was performed to assess the maximum and minimum velocity, resistance and pulsatility index of middle cerebral artery of the foetuses. Results: Echoencephalography was performed to evaluate the morphological characteristics of the central nervous system. Cerebral echobiometry indicated an increase in area and volume of the hemispheres and cranium (P<0·001) but no changes in BMI or BVI over the gestational period studied. Doppler ultrasonography identified increases in peak systolic velocity (P=0·0188) and end diastolic velocity (P=0·0274) and decreases in resistance index (P=0·0002) and pulsatility index (P<0·001). Clinical Significance: Echoencephalography and spectral Doppler ultrasonography of the middle cerebral artery in canine foetuses might be a useful technique for prenatal care. © 2013 British Small Animal Veterinary Association.
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Annually hundreds of crab-eating foxes (Cerdocyon thous) are referred to rehabilitation centers and zoos in Brazil. The ultrasonographic study of wildlife species is an important tool for a non-invasive and accurate anatomical description and provides important information for wildlife veterinary care. The aim of the present study was to determine the characteristics of the main abdominal organs as well as the vascular indexes of the abdominal aorta and renal arteries of crab-eating foxes (Cerdocyon thous) using mode B ultrasonography and Doppler ultrasonography, respectively. Ultrasonographic features of the main abdominal organs were described and slight differences were noticed between ultrasound imaging of abdominal organs of crab-eating foxes and other species. The bladder presented wall thickness of 12 +/- 0.01 mm, with three defined layers. Both, the right and left kidneys presented corticomedullary ratio of 1: 1 and similarly to the adrenals and the liver, they were homogeneous and hypoechoic compared to the spleen. The spleen was homogeneous and hyperechoic compared to the kidneys. The stomach presented 3 to 5 peristaltic movements per minute, wall thickness of 39 +/- 0.05 mm and lumen and mucosa with hyperechoic and hypoechoic features, respectively. Small and large intestines presented 2 to 3 peristaltic movements per minute, wall thickness of 34 +/- 0.03 mm and three defined layers with hyperechogenic (submucosa and serosa) and hypoechogenic (muscular) features. Ovaries of the female crab-eating fox were hypoechoic compared to the spleen and with heterogeneous parenchyma due to the presence of 2x2 mm ovarian follicles. Prostates of the six males were regular and with a well defined boundary, with a homogeneous and hyperechoic parenchyma compared to the spleen. Vascular indexes of the abdominal aorta (PSV: 25.60 +/- 0.32 cm/s; EDV: 6.96 +/- 1.68cm/s; PI: 1.15 +/- 0.07 e RI: 0.73 +/- 0.07) and right (PSV: 23.08 +/- 3.34cm/s; EDV: 9.33 +/- 2.36cm/s; PI: 1.01 +/- 0.65 e RI: 0.65 +/- 0.16) and left renal arteries (PSV: 23.74 +/- 3.94cm/s; EDV: 9.07 +/- 3.02cm/s; PI: 1.04 +/- 0.31 e RI: 0.64 +/- 0.10) were determined. Thus, conventional and Doppler ultrasonographic imaging provides basic information that can be used as reference for the species as well for other wild canids and it is a precise and non-invasive method that can be safely used to evaluate and diagnose abdominal injuries in these patients.
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We evaluated 16 pregnant women with gestational age between 20 and 32 weeks in acute severe hypertension which were randomly allocated to receive either hydralazine or labetalol. Blood pressure and Doppler ultrasound parameters from maternal uterine and fetal middle cerebral and umbilical arteries were assessed during acute severe hypertension and after treatment. A significant reduction in systolic and diastolic blood pressure was observed in both groups. A significant change in Doppler parameters was observed only in pregnant women who received hydralazine: an increase in uterine arteries resistance index. We concluded that both drugs were highly effective in reducing blood pressure in these women. Despite the observed increase in resistance index of uterine arteries associated with hydralazine, the use of hydralazine and labetalol were not related to any significant changes in fetal Doppler, which is reassuring about the safety of these drugs when treating acute severe hypertension in pregnancy. (E-mail: wpmartins@gmail.com) (C) 2011 World Federation for Ultrasound in Medicine & Biology.
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BACKGROUND: Contrast-enhanced ultrasonography (CEUS) is a novel imaging technique that is safe and applicable on the bedside. Recent developments seem to enable CEUS to quantify organ perfusion. We performed an exploratory study to determine the ability of CEUS to detect changes in renal perfusion and to correlate them with effective renal plasma flow. METHODS: CEUS with destruction-refilling sequences was studied in 10 healthy subjects, at baseline and during infusion of angiotensin II (AngII) at low (1 ng/kg/min) and high dose (3 ng/kg/min) and 1 h after oral captopril (50 mg). Perfusion index (PI) was obtained and compared with the effective renal plasma flow (ERPF) obtained by parallel para-aminohippurate (PAH) clearance. RESULTS: Median PI decreased from 188.6 (baseline) to 100.4 with low-dose AngII (-47%; P < 0.02) and to 66.1 with high-dose AngII (-65%; P < 0.01) but increased to 254.7 with captopril (+35%; P > 0.2). These changes parallelled those observed with ERPF, which changed from a median of 672.1 mL/min (baseline) to 572.3 (low-dose AngII, -15%, P < 0.05) and to 427.2 (high-dose AngII, -36%, P < 0.001) and finally 697.1 (captopril, +4%, P < 0.02). CONCLUSIONS: This study demonstrates that CEUS is able to detect changes in human renal cortical microcirculation as induced by AngII infusion and/or captopril administration. The changes in perfusion indices parallel those in ERPF as obtained by PAH clearance.
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BACKGROUND AND PURPOSE: A right-to-left shunt can be identified by contrast transcranial Doppler ultrasonography (c-TCD) at rest and/or after a Valsalva maneuver (VM) or by arterial blood gas (ABG) measurement. We assessed the influence of controlled strain pressures and durations during VM on the right-to-left passage of microbubbles, on which depends the shunt classification by c-TCD, and correlated it with the right-to-left shunt evaluation by ABG measurements in stroke patients with patent foramen ovale (PFO). METHODS: We evaluated 40 stroke patients with transesophageal echocardiography-documented PFO. The microbubbles were recorded with TCD at rest and after 4 different VM conditions with controlled duration and target strain pressures (duration in seconds and pressure in cm H2O, respectively): V5-20, V10-20, V5-40, and V10-40. The ABG analysis was performed after pure oxygen breathing in 34 patients, and the shunt was calculated as percentage of cardiac output. RESULTS: Among all VM conditions, V5-40 and V10-40 yielded the greatest median number of microbubbles (84 and 95, respectively; P<0.01). A significantly larger number of microbubbles were detected in V5-40 than in V5-20 (P<0.001) and in V10-40 than in V10-20 (P<0.01). ABG was not sensitive enough to detect a shunt in 31 patients. CONCLUSIONS: The increase of VM expiratory pressure magnifies the number of microbubbles irrespective of the strain duration. Because the right-to-left shunt classification in PFO is based on the number of microbubbles, a controlled VM pressure is advised for a reproducible shunt assessment. The ABG measurement is not sensitive enough for shunt assessment in stroke patients with PFO.
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OBJECTIVE: Absent or reverse end-diastolic flow (Doppler II/III) in umbilical artery is correlated with poor perinatal outcome, particularly in intrauterine growth restricted (IUGR) fetuses. The optimal timing of delivery is still controversial. We studied the short- and long-term morbidity and mortality among these children associated with our defined management. STUDY DESIGN: Sixty-nine IUGR fetuses with umbilical Doppler II/III were divided into three groups; Group 1, severe early IUGR, no therapeutic intervention (n = 7); Group 2, fetuses with pathological biophysical profile, immediate delivery (n = 35); Group 3, fetuses for which expectant management had been decided (n = 27). RESULTS: In Group 1, stillbirth was observed after a mean delay of 6.3 days. Group 2 delivered at an average of 31.6 weeks and two died in the neonatal period (6%). In Group 3 after a mean delay of 8 days, average gestational age at delivery was 31.7 weeks; two intra uterine and four perinatal deaths were observed (22%). Long-term follow-up revealed no sequelae in 25/31 (81%) and 15/18 (83%), and major handicap occurred in 1 (3%) and 2 patients (11%), respectively, for Groups 2 and 3. CONCLUSION: Fetal mortality was observed in 22% of this high risk group. After a mean period of follow-up of 5 years, 82% of infants showed no sequelae. According to our management, IUGR associated with umbilical Doppler II or III does not show any benefit from an expectant management in term of long-term morbidity.
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OBJECTIVE: The goal of our study was to compare Doppler sonography and renal scintigraphy as tools for predicting the therapeutic response in patients after undergoing renal angioplasty. SUBJECTS AND METHODS. Seventy-four hypertensive patients underwent clinical examination, Doppler sonography, and renal scintigraphy before and after receiving captopril in preparation for renal revascularization. The patients were evaluated for the status of hypertension 3 months after the procedure. The predictive values of the findings of clinical examination, Doppler sonography, renal scintigraphy, and angiography were assessed. RESULTS: For prediction of a favorable therapeutic outcome, abnormal results from renal scintigraphy before and after captopril administration had a sensitivity of 58% and specificity of 57%. Findings of Doppler sonography had a sensitivity of 68% and specificity of 50% before captopril administration and a sensitivity of 81% and specificity of 32% after captopril administration. Significant predictors of a cure or reduction of hypertension after revascularization were low unilateral (p = 0.014) and bilateral resistive (p = 0.016) indexes on Doppler sonography before (p = 0.009) and after (p = 0.028) captopril administration. On multivariate analysis, the best predictors were a unilateral resistive index of less than 0.65 (odds ratio [OR] = 3.7) after captopril administration and a kidney longer than 93 mm (OR = 7.8). The two best combined criteria to predict the favorable therapeutic outcome were a bilateral resistive index of less than 0.75 before captopril administration combined with a unilateral resistive index of less than 0.70 after captopril administration (sensitivity, 76%; specificity, 58%) or a bilateral resistive index of less than 0.75 before captopril administration and a kidney measuring longer than 90 mm (sensitivity, 81%; specificity, 50%). CONCLUSION: Measurements of kidney length and unilateral and bilateral resistive indexes before and after captopril administration were useful in predicting the outcome after renal angioplasty. Renal scintigraphy had no significant predictive value.
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OBJECTIVE: To determine the usefulness of computed tomography (CT), magnetic resonance imaging (MRI), and Doppler ultrasonography (US) in providing specific images of gouty tophi. METHODS: Four male patients with chronic gout with tophi affecting the knee joints (three cases) or the olecranon processes of the elbows (one case) were assessed. Crystallographic analyses of the synovial fluid or tissue aspirates of the areas of interest were made with polarising light microscopy, alizarin red staining, and x ray diffraction. CT was performed with a GE scanner, MR imaging was obtained with a 1.5 T Magneton (Siemens), and ultrasonography with colour Doppler was carried out by standard technique. RESULTS: Crystallographic analyses showed monosodium urate (MSU) crystals in the specimens of the four patients; hydroxyapatite and calcium pyrophosphate dihydrate (CPPD) crystals were not found. A diffuse soft tissue thickening was seen on plain radiographs but no calcifications or ossifications of the tophi. CT disclosed lesions containing round and oval opacities, with a mean density of about 160 Hounsfield units (HU). With MRI, lesions were of low to intermediate signal intensity on T(1) and T(2) weighting. After contrast injection in two cases, enhancement of the tophus was seen in one. Colour Doppler US showed the tophi to be hypoechogenic with peripheral increase of the blood flow in three cases. CONCLUSION: The MR and colour Doppler US images showed the tophi as masses surrounded by a hypervascular area, which cannot be considered as specific for gout. But on CT images, masses of about 160 HU density were clearly seen, which correspond to MSU crystal deposits.
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We present a 34-year-old patient with digital necrosis due to thromboangiitis obliterans. He was successfully treated with iloprost, a prostaglandin analogue. Duplex ultrasonography was performed during the perfusion of iloprost to optimize the doses and the treatment duration. A complete revascularization was observed after 10 days. Iloprost perfusions were stopped, and a slow regression of the necroses was observed in the subsequent days. With the use of duplex ultrasonography, unnecessary high doses of iloprost and long periods of treatment can be avoided reducing side effects and treatment costs.
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BACKGROUND: Angiographic studies suggest that acute vasospasm within 48 h of aneurysmal subarachnoid hemorrhage (SAH) predicts symptomatic vasospasm. However, the value of transcranial Doppler within 48 h of SAH is unknown. METHODS: We analyzed 199 patients who had at least 1 middle cerebral artery (MCA) transcranial Doppler examination within 48 h of SAH onset. Abnormal MCA mean blood flow velocity (mBFV) was defined as >90 cm/s. Delayed cerebral ischemia (DCI) was defined as clinical deterioration or radiological evidence of infarction due to vasospasm. RESULTS: Seventy-six patients (38%) had an elevation of MCA mBFV >90 cm/s within 48 h of SAH onset. The predictors of elevated mBFV included younger age (OR = 0.97 per year of age, p = 0.002), admission angiographic vasospasm (OR = 5.4, p = 0.009) and elevated white blood cell count (OR = 1.1 per 1,000 white blood cells, p = 0.003). Patients with elevated mBFV were more likely to experience a 10 cm/s fall in velocity at the first follow-up than those with normal baseline velocities (24 vs. 10%, p < 0.01), suggestive of resolving spasm. DCI developed in 19% of the patients. An elevated admission mBFV >90 cm/s during the first 48 h (adjusted OR = 2.7, p = 0.007) and a poor clinical grade (Hunt-Hess score 4 or 5, OR = 3.2, p = 0.002) were associated with a significant increase in the risk of DCI. CONCLUSION: Early elevations of mBFV correlate with acute angiographic vasospasm and are associated with a significantly increased risk of DCI. Transcranial Doppler ultrasound may be an early useful tool to identify patients at higher risk to develop DCI after SAH.
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OBJECTIVE: Transcranial Doppler (TCD) is widely used to monitor the temporal course of vasospasm after subarachnoid hemorrhage (SAH), but its ability to predict clinical deterioration or infarction from delayed cerebral ischemia (DCI) remains controversial. We sought to determine the prognostic utility of serial TCD examination after SAH. METHODS: We analyzed 1877 TCD examinations in 441 aneurysmal SAH patients within 14 days of onset. The highest mean blood flow velocity (mBFV) value in any vessel before DCI onset was recorded. DCI was defined as clinical deterioration or computed tomographic evidence of infarction caused by vasospasm, with adjudication by consensus of the study team. Logistic regression was used to calculate adjusted odds ratios for DCI risk after controlling for other risk factors. RESULTS: DCI occurred in 21% of patients (n = 92). Multivariate predictors of DCI included modified Fisher computed tomographic score (P = 0.001), poor clinical grade (P = 0.04), and female sex (P = 0.008). After controlling for these variables, all TCD mBFV thresholds between 120 and 180 cm/s added a modest degree of incremental predictive value for DCI at nearly all time points, with maximal sensitivity by SAH day 8. However, the sensitivity of any mBFV more than 120 cm/s for subsequent DCI was only 63%, with a positive predictive value of 22% among patients with Hunt and Hess grades I to III and 36% in patients with Hunt and Hess grades IV and V. Positive predictive value was only slightly higher if mBFV exceeded 180 cm/s. CONCLUSION: Increased TCD flow velocities imply only a mild incremental risk of DCI after SAH, with maximal sensitivity by day 8. Nearly 40% of patients with DCI never attained an mBFV more than 120 cm/s during the course of monitoring. Given the poor overall sensitivity of TCD, improved methods for identifying patients at high risk for DCI after SAH are needed.