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Biomedical subjects

E Ring

Publications and source records attributed to E Ring.

At least 19 recordsLinked to original sources
PubMed2003

Potential applications of three-dimensional ultrasound in the pediatric urinary tract: pictorial demonstration based on preliminary results.

The aim of this study was to describe the potential of three-dimensional ultrasound (3DUS) in the urinary tract of neonates, infants, and children. The potential applications are illustrated based on our experience in 80 patients using two different 3DUS techniques. Various disease entities throughout the neonatal and pediatric age have been evaluated. The potential of 3DUS is discussed based on comparison with conventional 2DUS or other imaging (as clinically indicated), focused on the potentially improved renal parenchymal volume assessment. In our experience, 3DUS is feasible in neonates, infants, and children without sedation. It reduces imaging time, improves demonstration of complex anatomy and allows for evaluation of anatomy/pathology in any plane. The 3DUS improves volume assessment and follow-up comparison by offering an improved standardization and documentation. Rendered views of the dilated collecting system enable a comprehensive demonstration of hydronephrosis similar to intravenous urography or MR urography images. Additionally, 3DUS offers an ideal tool for training and education. Yet, limitations have to be acknowledged: areas inaccessible for 2DUS; poor quality of the original 2DUS acquisition; limited resolution; patient motion and breathing; cardiac pulsation creating artifacts and misregistration; equipment cost; lack of 3D DICOM standards creating problems with data storage; as well as system-inherent technical limitations. Nevertheless, the 3DUS holds the potential to become a valuable additional imaging tool for sonographic evaluation of the pediatric urinary tract.

Adolescent↗
PubMed2001

Feasibility of MR urography in neonates and infants with anomalies of the upper urinary tract.

The aim of this study was to evaluate the feasibility and diagnostic potential of dynamic MR urography (MRU) in neonates and infants with sonographically detected abnormalities of the upper urinary tract. Thirty infants (age range 5 days to 3 years, mean age 7.9 months; male:female: 22:8) underwent MRU using T2 and contrast-enhanced dynamic T1-weighted sequences. The results were compared with the findings of ultrasound ( n=30), intravenous urography (IVU, n=19) and/or scintigraphy ( n=25) based on the criteria suggestive of obstructive uropathy. Oral sedation was sufficient to perform MRU with diagnostic quality in 20 of 21 patients younger than 1 year; 9 older patients needed intravenous sedation. Diagnosis of the 66 renal units (58 kidneys, 29 successful examinations) included normal systems (contralateral units), duplex systems, vesico-ureteral reflux, obstructive megaureter, ureteropelvic junction obstruction and accompanying renal parenchymal disease, with complex pathology in 10 patients. Magnetic resonance urography demonstrated anatomy better than IVU, particularly the renal parenchyma, (ectopic) ureters, and poorly functioning dilated systems. Magnetic resonance urography was superior to US in showing ureteral pathology. Tiny cysts in dysplastic kidneys were better seen by US. Gadolinium-enhanced dynamic MRU allowed accurate assessment of obstruction applying IVU criteria. Here MRU matched IVU results, and most of the scintigraphic findings. Magnetic resonance urography can be performed in young infants with diagnostic quality using oral sedation. Magnetic resonance urography correctly depicts anatomy and allows assessment of the urinary tract better than US and IVU, with additional functional information. Magnetic resonance urography thus has the potential to replace IVU for many indications.

Feasibility Studies↗
PubMed2001

Effects of brash removal after clear felling on soil and soil-solution chemistry and field-layer biomass in an experimental nitrogen gradient.

Biofuels, such as brash from forest fellings, have been proposed as an alternative energy source. Brash removal may affect the sustainability of forest production, e.g., through a change in the availability of cations and N in the soil. We report initial effects of brash removal on inorganic N content in humus and mineral soil, soil-solution chemistry, and field-layer biomass after clear felling an N-fertilisation experiment in central Sweden. The experiment comprised six different fertiliser levels, ranging from 0 to 600 kg N ha(-1). Urea was given every 5th year during 1967 to 1982 to replicated plots, giving total doses of 0 to 2400 kg N ha(-1). Clear felling took place in 1995, 13 years after the last fertilisation. The removal of brash decreased the NO3- content in the humus layer after clear felling. A decrease in the NO3- concentration of the soil solution was indicated during most of the study period as well. No effect of the previous N fertilisation was found in the humus layer, but in the mineral soil there was an increase in NO3- content for the highest N dose after clear felling ( p = 0.06). The soil-solution chemistry and the field-layer biomass showed an irregular pattern with no consistent effects of brash removal or previous fertilisation.

Agriculture↗
PubMed2001

Amplitude coded-colour Doppler sonography in paediatric renal disease.

The aim of our study was to assess the ability of amplitude coded-colour Doppler sonography (ACDS) to depict altered perfusion in paediatric renal disease in a prospective study. Colour Doppler sonography (CDS) and ACDS examinations were performed in 180 renal units (90 patients; age range newborn to 16 years) with unilateral or bilateral renal disease (e.g. reflux nephropathy, renal scars, end-stage renal disease, ureteropelvic junction obstruction, urinary tract infection, renal failure, haemolytic uraemic syndrome, nephrotic syndrome, systemic lupus erythematosus (LE), renal biopsy, congenital dysplasia, tumour/infiltration). The ACDS results were compared with scintigraphy or CT as well as to clinical findings. Amplitude colour-coded Doppler sonography accurately demonstrated normal vasculature in 49 of 51 healthy kidneys (= 96%); 3 healthy kidneys could not be evaluated due to motion/artefacts. In 39 of 43 kidneys with focally altered perfusion ACDS could be performed and correctly depicted focally impaired vasculature/perfusion in 35 kidneys (= 89.7%). Seventy-three of 83 kidneys with diffusely impaired perfusion could be evaluated by ACDS and altered pattern was correctly depicted in 58 kidneys (= 79.4%), with an overall percentage of agreement of 87.1%. Amplitude CDS appears to be useful in infants and children. Compared with CDS it improves visualisation of especially focally impaired vasculature/perfusion and should be considered a valuable adjunct to conventional investigations.

Adolescent↗
PubMed1998

Application of M-mode sonography to functional evaluation in pediatric patients.

To assess the feasibility and advantages of functional motion-mode (M-mode) sonography in pediatric patients with various non-cardiac M-mode applications, 50 patients aged 6 days to 14.5 years with megaureter, diaphragmatic palsy and spinal cord malformation were studied. In addition to initial conventional brightness-mode gray-scale ultrasound. M-mode sonography was performed for evaluation of motion and possible impairment. The findings were compared with other imaging results. The impact of the sonographic results on clinical management was evaluated retrospectively. Impaired motion was demonstrated by conventional sonography in all cases. Only M-mode sonography enabled adequate documentation for comparison with follow-up examinations, but allowed only semiquantitative assessment. Thus even gradual improvement or deterioration can be followed in an unbiased way by using a better-documented investigation for comparison, though an objective 'ranking', especially of diaphragmatic movement, could not be achieved. M-mode sonography enables a non-invasive and non-ionizing evaluation and documentation of motion impairment in pediatric patients. It improves documentation of motion and enables a better comparison with previous findings. It is especially useful for follow-up in evolving disease.

Adolescent↗
PubMed1998

Urinary N-acetyl-beta-D-glucosaminidase activity in patients with cystic fibrosis on long-term gentamicin inhalation.

OBJECTIVE: To investigate possible renal toxicity of long-term gentamicin inhalation in patients with cystic fibrosis. METHODS: Urinary N-acetyl-beta-D-glucosaminidase (NAG) activity was measured during routine respiratory clinic visits. Outpatient records were reviewed for data on long-term gentamicin inhalation, and parents and patients were interviewed for compliance. Exclusion criteria were irregular gentamicin inhalation, urinary infection or other febrile illness, intravenous aminoglycoside treatment during the previous three months, and diabetes mellitus. Patients were assigned to three groups: group 1, current gentamicin inhalation; group 2, previous gentamicin inhalation that had been stopped at least three months ago; and group 3, never any gentamicin inhalation. RESULTS: 52 patients (34 girls, 18 boys), mean (SD) age 11.5 (5.7) years, entered the study. Patients currently on gentamicin inhalation (n = 20) were significantly younger and had higher urinary NAG activity (0.83 (0.57) U/mmol creatinine) than the 23 patients without gentamicin inhalation (0.26 (0.10) (p = 0.0001) and the nine patients with previous gentamicin inhalation (0.32 (0.15) (p = 0.0125). Twelve patients on current gentamicin inhalation had raised NAG values but all those in groups 2 and 3 had NAG values within the normal range. In patients currently on gentamicin inhalation, there was a positive correlation between urinary NAG activity and cumulative dose of nebulised gentamicin (r = 0.60, p = 0.0049). CONCLUSIONS: Long-term gentamicin inhalation in patients with cystic fibrosis poses a risk of renal toxicity. It is not known whether further treatment might result in more severe renal damage.

Acetylglucosaminidase↗
PubMed1998

Arteriovenous fistula after renal biopsy in children.

Our objective was to assess the prevalence and history of arteriovenous fistula after renal biopsy in pediatric patients by the use of color Doppler sonography. Fifty patients, aged 6 days to 18.5 years, underwent sonographically guided renal biopsy. Color Doppler sonography was performed prior to, during, and after the procedure. Postbiopsy hematoma was detected in 46 patients (92%), of whom 10 suffered clinically significant bleeds. Six patients (age range, 8 to 18.5 years) developed postbiopsy arteriovenous fistula. In three cases the arteriovenous fistula diminished spontaneously, one persisted without symptoms, and two symptomatic arteriovenous fistulas needed coil implantation. Color Doppler sonography demonstrated all arteriovenous fistulas 4 hours after the procedure and duplex Doppler sonography demonstrated the flow disturbances in the feeding and draining vessels. We conclude that color Doppler sonography allows noninvasive detection and follow-up study of postbiopsy arteriovenous fistula, thus helping to define management after interventional procedures.

Adolescent↗
PubMed1998

Continuous renal replacement therapy in critically ill patients.

We describe our experience with continuous renal replacement therapy (CRRT) in critically ill neonates. From June 1995 to June 1997 36 critically ill oliguric or anuric infants and children underwent continuous arterio-venous (N = 17) or veno-venous (N = 15) renal support. In addition, four neonates were treated with continuous ultrafiltration (CUF) during extracorporeal membrane oxygenation (ECMO) because of severe diuretic-resistant hypervolemia. Their mean age was 9.8 +/- 1.5 days, their mean body weight 3.0 +/- 0.1 kg. The membrane surface area of the hemofilters ranged from 0.015 m2 to 0.2 m2 and the priming volume from 3.7 to 15 ml. For pump-driven hemofiltration a roller pump with pressure alarms, an air trap, an air bubble detector, and small blood lines was used. Fluid balance was controlled by a microprocessor controlled unit. The ultrafiltrate substitution fluid was based on bicarbonate in the majority of the patients and was partially or totally replaced according to the clinical situation. The mean duration of renal support was 97 +/- 20 hours, ranging from 14 to 720 hours. During arterio-venous and veno-venous hemofiltration the mean blood flow rates were 7.0 +/- 1.2 ml/min and 23.1 +/- 2.4 ml/min (P < 0.01), respectively, and the mean ultrafiltration rates 3.3 +/- 0.4 and 9.5 +/- 1.9 ml/min/m2 (P < 0.01), respectively. During continuous hemodiafiltration urea clearances increased by 300%. Overall survival rate was 66%. CRRT related complications included local bleeding at the catheter entrance site, partial thrombosis of the inferior or superior caval veins and transient ischemia due to femoral artery catheters. Continuous hemofiltration either driven in the arterio-venous or veno-venous mode is a very effective method of renal support for critically ill neonates to control fluid balance and metabolic derangement. Urea clearance can be improved by adding some dialysate fluid in a countercurrent direction to blood flow.

Acute Kidney Injury↗
PubMed1997

The sonographically thickened wall of the upper urinary tract system: correlation with other imaging methods.

BACKGROUND: Sonographically detected, upper urinary tract wall thickening (UUTWT) was reported to occur in urinary tract infection, urinary tract stone disease, rejection after renal transplantation and vesico-ureteral reflux (VUR). A possible association with obstruction can be hypothesized. OBJECTIVE: The assessment of a potential relationship of UUTWT with VUR or obstruction in patients without one of the above-mentioned conditions. MATERIALS AND METHODS: We analyzed 38 patients (74 upper urinary tracts) with at least unilateral UUTWT and concomitant imaging studies such as voiding cystourethrography (VCU), intravenous urography (IVU) and diuretic renography (DR). RESULTS: At sonography 49 urinary tracts showed UUTWT. In 33, ipsilateral VUR could be demonstrated at VCU, 11 revealed obstruction at IVU and/or DR, and 4 showed non-obstructive pelvicalyceal dilatation at IVU and DR. In one patient, all imaging studies were normal. The positive predictive value of UUTWT for the presence of VUR was 67.4 % and for obstruction it was 22.5 %. Altogether, UUTWT indicated pathology in 98 % of urinary tracts. CONCLUSION: After exclusion of urinary tract infection, urinary stone disease and prior renal transplantation, the most common associated findings in UUTWT are VUR and obstruction. Therefore, VCU seems to be justified in all cases of UUTWT. Nonrefluxing systems should be further evaluated with DR and/or IVU for exclusion of obstruction.

Child↗
PubMed1997

[Evaluation of renal vascularization using amplitude-coded Doppler ultrasound].

PURPOSE: To evaluate the benefit of "Colour Doppler Energy" (CDE) or "Power Doppler" applications in healthy kidneys and in renal disease including paediatric assessment. PATIENTS AND METHOD: Ten healthy volunteers (range: neonate to adults) were studied using conventional colour Doppler sonography (CDS) and CDE in order to evaluate the visibility of intrarenal vasculature. In addition, ten children and ten adults with known renal disease were evaluated. The findings were compared to clinical, scintigraphic and biopsy results. RESULTS: CDE showed far better visualisation of intrarenal vasculature than CDS. CDE demonstrated focal and diffuse reduced cortical perfusion with an overall accuracy of 95% and a sensitivity of 88%. In 7 healthy volunteers cortical vasculature was visualised throughout the kidney. In 3 infants incomplete visualisation was obtained because of motion artifacts. In the diseased kidneys, CDE findings correlated well with clinical findings, scintigraphy results and biopsy findings. CONCLUSION: CDE can be successfully applied to adults and infants demonstrating renal vasculature in healthy kidneys and in kidneys with focally or diffusely altered perfusion.

Adolescent↗
PubMed1995

Liver transplantation for hepatocellular carcinoma: results with preoperative chemoembolization.

At the University of California, San Francisco, 17 patients who met the following criteria-hepatic tumor unresectable because of location or inadequate liver reserve, no metastases, HBsAg negative, no tumor larger than 5 cm in diameter, and no more than three tumors--were enrolled prospectively in a protocol employing preoperative chemoembolization to assess whether orthotopic liver transplantation (OLT) could cure a majority of highly selected patients with hepatocellular carcinoma (HCC). Thirteen patients had biopsy-proven HCC, 2 had the fibrolamellar variant, and 2 had radiological findings of HCC but no biopsy confirmation. Fourteen had underlying liver disease. All arteriographically apparent lesions were chemoembolized using a mixture including Gelfoam powder, doxorubicin, mitomycin-c, and cisplatin. Eight patients with poor hepatic reserve were chemoembolized when a donor organ became available, whereas 9 patients were chemoembolized and then placed on the waiting list. The only complication of chemoembolization was a gangrenous gallbladder in 1 patient. Thirteen patients underwent liver transplantation (2 patients without prior histological confirmation of carcinoma had no identifiable tumor at OLT); 3 patients developed metastases between the time of enrollment and donor organ availability and subsequently died; and 1 patient underwent a trisegmentectomy. Ten of the 11 patients with biopsy-proven HCC who underwent transplantation remain free of recurrent cancer at a median of 40 months; 1 patient died at 6 months of lymphoproliferative disease with no cancer found at autopsy. Although the role of chemoembolization is uncertain, these data show that the majority of carefully selected patients with HCC may achieve long-term survival with OLT.

Angiography↗
PubMed1995

Ventriculoscopy-aided implantation of ventricular shunts in patients with hydrocephalus.

Ventriculoscopy represents a new concept in the surgical treatment of children with hydrocephalus. Optimal catheter position can now be achieved with the help of a new method consisting of endoscopically controlled implantation of ventricular shunts. In addition, interventional ventriculoscopy enables or improves new operative procedures such as the fenestration of intracranial cysts or the removal of dislodged parts of catheter tips from the corresponding ventricle under direct optical control. Ventriculoscopy has been performed on 17 pediatric patients, with no complications to date.

Catheterization↗
PubMed1995

[Ultrasound-guided kidney biopsy in childhood--role of color Doppler ultrasound].

Thirty five patients (median age 9.5 years, male:female = 14:21) underwent sonographically guided kidney puncture. Sonographically guided puncture was done with a 14 Gauge puncture needle. In all patients sufficient material was obtained for histological diagnosis. After puncture slight subcapsular and perirenal bleeding was seen in all cases, 16 patients showed minor parenchymal bleeding, 9 patients had sonographic signs of bleeding into the collecting system, and three of them developed blood clots within the pelvic system causing obstruction in two cases. Following renal biopsy 3 patients developed arteriovenous shunting, which was nicely demonstrated at an early stage by colour Doppler sonography. Other changes in kidney perfusion due to kidney biopsy were monitored by colour Doppler sonography, none of those changes could be related to other data. One of the arteriovenous fistulae resolved spontaneously, one still persists to date without clinical symptoms, the third caused severe bleeding and needed embolisation. Our observations suggest that AV-shunts are more common then suggested previously and they can be readily detected by colour Doppler sonography.

Adolescent↗
PubMed1995

[Prenatal diagnosis of abnormalities of the urinary tract].

During the period January 1983 to December 1993 malformations of the urinary tract were suspected in 166 cases prenatally and confirmed after birth. Boys dominated (72% of cases); in 66% of the cases the malformation was unilateral. The most frequent diagnosis was ureteropelvic obstruction in 74 infants (45%). 73 out of 166 infants (44%) required surgical intervention. Altogether 124 operations were performed (68% temporary diversions; 32% definitive corrections). The high number of required interventions already during the first month of life highlights the importance of prenatal screening for the early detection of urinary tract malformations, especially obstructive uropathy and multicystic-dysplastic kidney. On the other hand, vesicouretal reflux is usually detected only postnatally on investigation of a urinary tract infection.

Diagnostic Imaging↗
PubMed1993

Primary vesicoureteral reflux in infants with a dilated fetal urinary tract.

Vesicoureteral reflux (VUR) was recognized neonatally by voiding cystography in 25 of 117 infants with a dilated fetal urinary tract. There was a male preponderance (76%) and a high percentage (40%) of associated urinary malformations. Thirty-nine refluxing units were studied. All grades of VUR were detected but gross dilating VUR dominated (59%). Spontaneous resolution was excellent in lower grades of VUR but was poor in gross VUR. Surgery was successfully performed in 13 renal units of nine patients with gross reflux, additional ipsilateral malformations, or pyelonephritis during antibiotic prophylaxis. Segmental renal scars developed in four kidneys after urinary infections, and a diffuse parenchymal lesion was noted in nine kidneys even at birth. One boy with duplication had a non-functioning refluxing system. Our results in a small number of infants show differences to children with VUR detected after urinary infections and seem to support the existence of a congenital reflux nephropathy.

Cystostomy↗