Congenital megacalyces. Ultrasound appearance.
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Dilatation, Pathologic↗
Biomedical subjects
K J Taylor
Publications and source records attributed to K J Taylor.
Congenital absence of the portal vein in oculoauriculovertebral dysplasia (Goldenhar syndrome).
Absence of the portal vein with systemic visceral venous return was demonstrated in an 8-year old girl with oculoauriculovertebral dysplasia (Goldenhar syndrome) during preoperative evaluation of a liver mass. Congenital absence of the portal vein is a rare malformation of potential clinical significance.
Angiography↗
Hepatic artery pseudoaneurysm: diagnosis with real-time and pulsed Doppler US.
Duplex ultrasonography (US), consisting of real-time and pulsed Doppler US, was used to identify a pseudoaneurysm in a patient with recurrent bleeding and chronic pancreatitis. The authors present a case that illustrates the limitations of real-time US in evaluating sonolucent masses in pancreatitis and the need for using pulsed Doppler technique.
Aneurysm↗
Renal allografts in acute rejection: evaluation using duplex sonography.
Sixty-nine duplex sonographic studies were performed in 24 patients who had received renal allografts. After a prospective qualitative analysis of the Doppler waveforms, results were correlated with biopsy material and each patient's clinical course. Increased pulsatility of the Doppler waveform of intrarenal arterial flow constituted an abnormal study, indicating acute rejection. Overall sensitivity varied with the histologic form of rejection, with a 60% sensitivity for acute interstitial rejection with or without vascular rejection and an 82% sensitivity for acute vascular rejection. Overall specificity was 95% and 96%, respectively. Early rejection was also accurately detected in three patients less than 48 hours following kidney transplantation. Duplex sonography has a useful role in evaluating posttransplantation renal failure. Abnormal study results may obviate the need for biopsy and help in guiding clinical management.
Adolescent↗
Liver transplant recipients: portable duplex US with correlative angiography.
Twenty patients, aged 4 months to 58 years, were evaluated for liver transplantation by duplex sonography, and 15 transplantations were completed; 42 postoperative examinations were performed. Sonographic findings were correlated with seven preoperative and five postoperative angiographic evaluations. Preoperative duplex US findings included tumors, portal vein occlusion, varices, biliary obstruction, and variant vascular anatomy. Postoperative findings included hepatic artery occlusion, portal vein occlusions (one with cavernous transformation), portal vein stenosis, biliary obstruction, intrahepatic and extrahepatic fluid collections, and air in the portal vein due to ischemic bowel. Use of angiography allowed confirmation of the vascular abnormalities and demonstrated evidence of rejection in patients with normal Doppler waveforms. Duplex sonography is a valuable portable technique for evaluating these patients and can be used in triage of patients requiring angiography.
Adolescent↗
Quantitative US attenuation in normal liver and in patients with diffuse liver disease: importance of fat.
Two methods are used to estimate ultrasound attenuation in liver. These were based on amplitude change and frequency change as a result of depth dependent attenuation. Evaluation of the two methods against a family of calibrated phantoms yielded correlation coefficients of 0.98 and 0.99, respectively. Liver attenuation in 26 control subjects was 0.50 and 0.52 dB/MHz/cm, respectively. Liver attenuation was estimated in 50 patients who later underwent liver biopsy. Comparison with quantitative histologic results showed that the presence of fat alone accounted for the increased attenuation associated with cirrhosis. Similar high attenuation values were found in patients with fatty infiltration. Fibrosis alone did not result in elevated liver attenuation. Cirrhotics without fatty infiltration had attenuation similar to that of the controls. Mechanisms of action are discussed.
Adolescent↗
Regenerating nodules in cirrhosis: sonographic appearance with anatomic correlation.
A sonographic-anatomic correlation study was undertaken to define the sonographic appearance of regenerating nodules in cirrhotic livers. Three cirrhotic livers with multiple regenerating nodules were obtained from patients undergoing liver transplantation. Sonograms of the resected livers were made and correlated directly with the anatomic specimens. Using a 3-MHz transducer, no discrete alterations in the echo texture of the livers were seen to correspond to the regenerating nodules. With a 7.5-MHz transducer, discrete islands of liver parenchyma were identified corresponding to regenerating nodules anatomically. The nodules were recognized because of visualization of thin, slightly more echogenic borders, which corresponded pathologically to fibrous and fatty connective tissue surrounding and separating the nodules.
Humans↗
Artifacts in ultrasound imaging.
Ultrasound imaging artifacts of acoustic origin relating to resolution, propagation path, and attenuation are reviewed. Lateral and axial resolution limitations are artifactual in nature since a failure to resolve means a loss of detail and two adjacent structures may be visualized as one. Apparent resolution close to the transducer (speckle) is not directly related to tissue texture but is a result of interference effects from the distribution of scatterers in the tissue. Reverberation produces a set of equally spaced artifactual echoes distal to the real reflectors. The mirror image artifact is the presentation of objects that are present on one side of a strong reflector, appearing on the other side as well. Shadowing and enhancement are useful artifacts for determining the nature of masses. Enhancement results from low attenuation objects in the sound path while shadowing results from strongly reflecting or strongly attenuating objects. Additional artifacts include section thickness, refraction, multipath, side lobe, grating lobe, focal enhancement, comet tail, ring down, speed error, and range ambiguity.
Diagnostic Errors↗
Noninvasive carotid artery evaluation by duplex Doppler.
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Arteriosclerosis↗
Serial estimation of serum angiotensin converting enzyme activity during and after pregnancy in a woman with sarcoidosis.
Serum angiotensin converting enzyme activities were estimated during pregnancy and the puerperium in a woman with sarcoidosis and a series of normal women. In the patient with sarcoidosis angiotensin converting enzyme activity was raised during pregnancy, particularly at 21 weeks' gestation, yet she remained well with no symptoms to suggest relapse of sarcoidosis. Serum angiotensin converting enzyme activity may not be of value in monitoring sarcoidosis activity during pregnancy.
Adult↗
Randomized indomethacin trial for prevention of intraventricular hemorrhage in very low birth weight infants.
We admitted 48 preterm neonates (600 to 1250 gm birth weight, normal 6-hour echoencephalograms) to a randomized prospective indomethacin or placebo trial for the prevention of neonatal intraventricular hemorrhage. Beginning at 6 postnatal hours, indomethacin or placebo was administered intravenously every 12 hours for a total of five doses. Cardiac ultrasound studies to assess the status of the ductus arteriosus were performed at 6 postnatal hours and on day 5. Urinary output, serum electrolytes, and renal and clotting functions were monitored. No differences in birth weight, gestational age, Apgar scores, or ventilatory needs were noted between the two groups. Six infants given indomethacin had intraventricular hemorrhage, compared to 14 control infants (P = 0.02). The indomethacin-treated group had significant decreases in serum prostaglandin values 30 hours after the initiation of therapy. The overall incidence of patent ductus arteriosus was 82% at 6 postnatal hours; 84% of the indomethacin-treated infants experienced closure of the ductus, compared to 60% of the placebo-treated patients. Closure of the ductus was not related to incidence of intraventricular hemorrhage. We speculate that indomethacin may provide some protection against neonatal intraventricular hemorrhage by acting on the cerebral microvasculature.
6-Ketoprostaglandin F1 alpha↗
Ultrasound Doppler flow studies of the ovarian and uterine arteries.
The feasibility of studying ovarian arterial blood flow has been demonstrated, using an ultrasonic method combining real-time imaging and pulsed Doppler (the 'duplex' method). Results using a percutaneous full-bladder technique were validated by comparison with use of an ultrasound probe applied directly to the arteries at laparotomy. The ovarian arteries demonstrated qualitatively and quantitatively distinct flow patterns compared with the internal and external iliac arteries. From recorded waveforms a pulsatility index (PI) reflecting vascular impedance was calculated. The PI was found to be lower, indicating increased blood flow, in the artery supplying the ovary carrying the dominant follicle or corpus luteum. Serial studies suggest that this change occurs at an early stage of the menstrual cycle, possibly before the dominant follicle can be recognized by its size or increased hormone production. Uterine arterial flow was also detectable, more accurately abdominally than vaginally, and the changes typical of late pregnancy were already found to be present, though to a lesser degree, in the first trimester.
Arteries↗
Blood flow in deep abdominal and pelvic vessels: ultrasonic pulsed-Doppler analysis.
Ultrasonic pulsed-Doppler signals from deep-lying vessels in the normal abdomen and pelvis are described. The signal characteristics combine to produce a Doppler "signature" that is specific for each vessel. The clinical potential of this method of deep flow detection is considered in relation to three areas of Doppler signal analysis: first, qualitative indication of the presence, direction, or absence of flow in a structure; second, more quantitative description of time velocity waveforms and Doppler spectral content; and third, the estimation of absolute volume flow. Limitations of these methods for the abdominal signals obtained are discussed.
Abdomen↗
Duplex Doppler: identification of cavernous transformation of the portal vein.
Three cases of cavernous transformation of the portal vein are presented, which emphasize the value of duplex Doppler sonography in the recognition of abnormal vascular structures. In all three cases, cavernous transformation was unsuspected; in two, the initial sonographic or CT examinations were interpreted incorrectly. These cases suggest that the combination of characteristic pulsed-Doppler waveforms and the real-time appearance of cavernous transformation is virtually diagnostic.
Adult↗
Neonatal periventricular leukomalacia: real-time sonographic diagnosis with CT correlation.
The utility of real-time sonography in the diagnosis of neonatal periventricular leukomalacia (PVL) has been described only recently. Six cases are reported of PVL diagnosed by serial real-time scanning. The sonographic findings were correlated with the computed tomographic findings and the clinical history. In five of six infants in whom scanning was performed, characteristic multiseptated periventricular cavitations developed 2-3 weeks after birth or later. A transition from normal to increased periventricular echogenicity was often observed before the development of the periventricular cavitations in nonhemorrhagic PVL. The parenchymal abnormality demonstrated by sonography correlated well with an abnormal neurologic outcome. It is suggested that serial real-time scanning be performed in neonates whose history suggests the possibility of hypoxic-ischemic brain injury. Nonspecific predictors of PVL include seizures, apnea, disturbed mental status, abnormal muscle tone, and leg weakness.
Cerebral Hemorrhage↗
Venereal disease in nineteenth-century children.
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Child Welfare↗
New criteria for the diagnosis of gestational trophoblastic disease.
The purpose of the study was to test the hypothesis of whether the combined use of ultrasound and human chorionic gonadotropin (hCG) determinations could increase the diagnostic accuracy of sonography in the diagnosis of hydatidiform mole. The criteria used were the absence of fetal heart movement by ultrasound when the hCG level was above 82,350 mIU/mL and the presence of an hCG level in excess of 2 SD above the mean for the biometrically derived gestational age for suspected partial moles. The threshold of 82,350 mIU/mL was derived by probit analysis of the hCG serum levels of a population of normal intrauterine pregnancies prospectively examined to determine the level of hCG at which fetal heart activity would be visible by sonography. The diagnostic accuracy of these criteria was compared with the preoperative sonographic examination in 36 hydatidiform moles. When sonography was used alone, 15 of 36 cases (41.6%) did not have a definitive diagnosis on the first examination. The combination of hCG and ultrasound would have correctly identified 32 of the 36 cases (88.8%). This improvement was statistically significant (P less than .005).
Abortion, Missed↗
Problems of tuberculosis in decline.
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Adrenal Insufficiency↗