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Biomedical subjects

M Riccabona

Publications and source records attributed to M Riccabona.

At least 19 recordsLinked to original sources
PubMed1999

Cerebral arteriovenous malformations: diagnostic value of echo-enhanced transcranial Doppler sonography compared with angiography.

BACKGROUND AND PURPOSE: The purpose of our study was to examine the clinical value of echo-enhanced transcranial power Doppler sonography (EE-TCD), including it ability to assess hemodynamic parameters of the intracranial vasculature, in patients with suspected cerebral arteriovenous malformations (AVMs) and to compare this method with angiography. METHODS: Sixteen patients with suspected cerebral AVMs were examined with EE-TCD and angiography. As an echo-enhancing agent, SHU 508A (Levovist) was administered intravenously by bolus injection in nine patients and by continuous infusion in seven. Sonograms were reviewed without knowledge of other imaging results and were correlated with angiographic findings. RESULTS: Angiography showed AVMs in 12 of 16 patients. Eleven lesions were located in the anterior or middle fossa and one was in the posterior fossa. EE-TCD was slightly less sensitive in the detection of AVMs (92%, 11/12 lesions), since in one patient the lacking acoustic window did not allow a transcranial examination. EE-TCD slightly underestimated AVM size compared with angiographic findings but showed feeding arteries with sufficient acoustic properties. In seven patients (58%), angiography revealed a coincidental blood supply from another intracranial or extracranial vessel, which was missed by EE-TCD in all cases. Assessment of peak systolic velocities and resistive indexes resulted in a higher (mean, 191.1 cm/s) and a lower (mean, 45.7%) value, respectively, in the feeding arteries as compared with the contralateral arteries (mean, 101.8 cm/s and 55.6%, respectively). Side-to-side differences were significantly higher in patients with AVMs than in those without a malformation. Signal enhancement was markedly longer with continuous infusion (mean, 520 seconds +/- 28.2) than with bolus injection (mean, 145 seconds +/- 10.5) of the contrast agent. CONCLUSION: In our limited study group, EE-TCD was a sensitive method for the detection of AVMs, and Levovist proved to be a safe and effective echo-enhancing substance.

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

Long-term use and tapered dose reduction of intranasal desmopressin in the treatment of enuretic children.

OBJECTIVE: To determine the time taken to achieve complete dryness, the management of desmopressin dosage to reduce the relapse rate, the mean dosage in those responding and any side effects of long-term treatment. PATIENTS AND METHODS: Enuretic children (155, 68% boys and 32% girls, mean age 8 years, range 5-19) were treated with desmopressin and assessed. Treatment (intranasal spray) was started with 20 microg desmopressin and titrated to 40 microg (maximum 50 microg) after 2 days if the child did not become dry within 48 h. The maximum dosage was maintained for at least 4-6 weeks. After 4 weeks of complete dryness, the dosage was reduced by 10 microg initially, and after each additional 4 dry weeks, by a further 10 microg; medication was stopped only after 4 dry weeks at 10 microg. RESULTS: Of the children, 85% responded to intranasal desmopressin therapy; 71% achieved complete dryness with no relapses, remaining dry with no further treatment, 7% achieved dryness after relapses during or after therapy, 7% improved (no more than two wet nights per week) and 15% did not respond to therapy or improved only slightly (> 2 wet nights per week). The mean duration of therapy was 28 weeks, the mean dose of desmopressin was 30 microg and the median follow-up 18 months. There were no significant side-effects. CONCLUSION: This study indicates that rapid titration until dryness within 1-3 days, a long maintenance therapy of at least 4-6 weeks and a slow stepwise reduction of dose decreases the frequency of relapse and improves the outcome.

Administration, Inhalation↗
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↗
PubMed1997

Assessment of lung function in neonates during extracorporeal membrane oxygenation.

We report our experience with pulmonary function testing in 11 out of 22 full-term neonates with severe respiratory failure, treated at the ECMO center Graz (Austria) during the period from 1990 to 1995. Altogether 17 out of 22 patients survived ECMO and all of them were successfully weaned from ECMO. Pulmonary function was assessed by monitoring expiratory tidal volume on the ventilator and estimating respiratory system compliance from the ratio tidal volume/(PIP-PEEP). In addition, compliance, and functional residual capacity were measured using a computerized pulmonary function system (PEDS). Compliance (mean +/- SD) decreased markedly after 24 hours of ECMO, compared with baseline values (0.20 +/- 0.12 vs 0.12 +/- 0.13 ml/cmH2O/kg) and was significantly higher (0.43 +/- 0.14 ml/cmH2O/kg, p < 0.01) before ECMO stop. When tidal volumes increased continuously ECMO blood flow could be decreased, indicating lung recovery. Most patients had a tidal volume of > 7 ml/kg prior to decannulation. Functional residual capacity and corresponding dynamic compliance, measured in 5 patients, ranged from 18.6 to 29.6 ml/kg and 0.49 to 0.57 ml/cmH2O/kg at this time. Functional residual capacity (mean +/- SD) increased significantly when surfactant was administered to promote weaning from ECMO (8.28 +/- 0.9 vs 19.0 +/- 1.0 ml/kg, p < 0.01). We conclude that the assessment of lung function has improved our understanding of pulmonary recovery during ECMO. Its clinical significance in determining the optimum time of weaning from ECMO needs further evaluation.

Extracorporeal Membrane Oxygenation↗
PubMed1997

Three-dimensional ultrasound: display modalities in obstetrics.

Three-dimensional ultrasound (3DUS) has recently been introduced into clinical practice. Various techniques are available for display of the volume data. We review the importance of selecting the proper display option and rendering mode depending on the specific diagnostic question. Current display options include (1) arbitrary planar images similar to conventional two-dimensional US images, (2) surface rendering with emphasis on soft tissues or skeletal detail, (3) stereo viewing using liquid crystal glasses or red/blue glasses, and (4) cine review of gated studies. Rotation of volume data also is important in understanding/comprehending patient anatomy. The range of rotation angles varies depending on the clinical setting. Also data storage requirements increase as the number of views increases.

Echocardiography, Doppler, Color↗
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

Venous thrombosis in and after extracorporeal membrane oxygenation: detection and follow-up by color Doppler sonography.

The purpose of our study was to evaluate thrombosis of venous vessels during and after extracorporeal membrane oxygenation (ECMO) using color Doppler sonography. We prospectively performed serial color Doppler sonography investigations in 30 ECMO patients [age: newborn to 3 years, male:female = 20:10, venoarterial (VA) ECMO = 18, venovenous (VV) ECMO = 12]. During ECMO obstruction and/or thrombosis of the superior vena cava (SVC) was observed in 2 neonates on VA ECMO. Furthermore, a thrombotic clot from an initially open duct of Arantii with partial portal vein thrombosis, reaching into the inferior vena cava (IVC), occurred despite adequate heparinization. After ECMO, late septic SVC thrombus occurred in one neonate. IVC thrombus was observed in two pediatric VV ECMO patients. The overall incidence of venous clots was 20 % (6 of 30). Routine color Doppler sonography monitoring of vessels in children on and after ECMO was found to be useful for early detection of venous thrombosis. It enabled consequent administration of appropriate therapy as well as follow-up after decannulation and reconstruction.

Child, Preschool↗
PubMed1997

Three-dimensional ultrasound of the fetal spine.

OBJECTIVE: To describe normal fetal spinal anatomy displayed by three-dimensional ultrasound and to determine whether three-dimensional ultrasound improves visualization of specific spinal defects. METHODS: Fetuses (n = 28) (16 normal and 12 abnormal) were examined on standard two- and three-dimensional sonographic equipment. RESULTS: In 15 of 16 normal fetuses, the spine was visualized at least from the upper thoracic area to the lower sacrum in a single three-dimensional image, and in 14 normal fetuses continuity of the ribs and spine was depicted. Neural tube defects were identified on both two- and three-dimensional ultrasounds; however, three-dimensional ultrasound displayed the level of the defect more accurately in three of the five cases. Scoliosis was recognized easily on a single three-dimensional rendered image, whereas several two-dimensional redered image, whereas several two-dimensional images were needed for the examiner mentally to reconstruct the scoliosis. CONCLUSION: Three-dimensional ultrasound may become an important tool for imaging of the fetal spine. Additional studies are necessary to determine the efficacy and cost effectiveness of this technology. However, our preliminary data suggest that presentation of the spine as a continuous structure rather than in independent two-dimensional views makes visualization of the spatial relationship of the spinal anatomy and adjacent structures easier. The ability to review the volume data using techniques not available on two-dimensional ultrasound may enable physicians to determine the extent of neural tube defects with more accuracy.

Female↗
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↗
PubMed1997

[Hydrocalicosis caused by a large renal artery aneurysm].

Rupture and development of hypertension represent frequent complications of renal artery aneurysms. We report the case of a 27-year-old patient with pain in the region of the right kidney due to a large renal artery aneurysm. This aneurysm induced partial, obstructive hydrocalicosis. The aneurysm was clearly differentiated from the dilated calices by color Doppler sonography and contrast-enhanced spiral CT.

Adult↗
PubMed1996

Three dimensional ultrasound: display modalities in the fetal spine and thorax.

PURPOSE: To evaluate the display modalities of three dimensional ultrasound (3D US) in the prenatal assessment of the fetal spine and thorax. METHOD: Twenty prenatal spine examinations (mean gestational age: 21 weeks, 15 normal findings, five pathological cases) were performed with a commercially available 3D US device. The visualization of fetal spine and rib anatomy and pathology by 3D US display was evaluated using various rendering methods and the optimal method was determined in regard to comprehensive diagnostic display. RESULTS: Demonstration of continuity of both the spine and the ribs could be achieved by 3D US. Visualization of clavicles, scapula and iliac bone was possible on rendered images. CONCLUSION: 3D US offers an additional diagnostic tool for prenatal assessment of the fetal spine and ribs; it provides a continuous demonstration of curved or tortuous structures in the rendered image. It improves comprehension of complex anatomy by providing a simultaneous display of all orthogonal sectional planes.

Female↗
PubMed1996

Activation of the clotting system during extracorporeal membrane oxygenation in term newborn infants.

OBJECTIVES: To determine the degree of clotting activation that occurs with the usual anticoagulation regimen with systemic heparinization. METHODS: To allow a standardized comparison of the patients, this study focused on the first 48 hours of extracorporeal membrane oxygenation (ECMO) in term newborn infants. The ECMO perfusion circuit consisted of a roller pump, silicone membrane lungs, and silicone rubber tubing. Coagulation was controlled routinely by measuring prothrombin time, fibrinogen, antithrombin III, and reptilase time. Platelet counts, activated clotting time, and heparin concentration were controlled regularly. The following specific activation markers of the clotting system were measured: prothrombin activation fragment 1 + 2(F1+2), thrombin-antithrombin III complexes, and D-dimer. Measurements were done before the start of ECMO, after 5 minutes, and at hours 1, 2, 3, 4, 6, 12, 24 and 48. RESULTS: All seven term infants had excessively high levels of clotting activation markers within the first 2 hours of ECMO: F1+2, 11.6(+/- O.9) nmol/L (mean +/- SEM); thrombin-antithrombin, 920(+/- 2.2) microg/L; D-dimer, 15.522(+/- 3.689) ng/L. During the next 46 hours of ECMO, F1+2 and thrombin-antithrombin III complexes decreased from those high values, whereas D-dimer did not. The increase of activation markers was accompanied by low fibrinogen, low platelet counts. and prolongation of reptilase time. CONCLUSIONS: These findings fit the pattern of consumptive coagulopathy during neonatal ECMO, especially in the first 24 hours.

Anticoagulants↗
PubMed1996

Three-dimensional ultrasound: accuracy of distance and volume measurements.

The aim of this study was to evaluate the accuracy of three-dimensional ultrasound distance and volume measurements using a commercially available three-dimensional ultrasound scanner. Sixty-two distance measurements were performed twice on an ultrasound tissue-mimicking phantom located in a water bath. Three-dimensional ultrasound distance measurements were compared to the actual distance. Volume measurements were made in a water bath with 21 balloons of various shapes ranging in volume from 20 ml to 490 ml. Three-dimensional ultrasound volume measurements were compared to actual balloon volumes and to conventional two-dimensional ultrasound volume calculations. The mean absolute error in three-dimensional ultrasound distance measurements was 1.0 +/- 0.8% (range, -2.3 to +1.9%) in the plane of acquisition and 1.0 +/- 0.6% (range, -2.0 to -0.2%) for planes with other orientations. Three-dimensional ultrasound volume measurements showed a mean absolute error of 6.4 +/- 4.4% (range, -6.0% to +15.5%), which was considerably better than two-dimensional ultrasound volume estimates having a mean absolute error of 12.6 +/- 8.7% (range, -27.5% to +39.2%). Volume measurements using two-dimensional ultrasound methods were much less accurate than three-dimensional ultrasound methods for irregularly shaped objects. In conclusion, our data show that three-dimensional ultrasound measurements of distance and volume are sufficiently accurate to use clinically.

Diagnostic Imaging↗
PubMed1996

[Value of ultrasound in diagnosis of celiac disease].

AIM: To evaluate the potential benefits of sonographic assessment in the diagnostic work-up of children suspected of having coeliac disease. METHOD: 39 infants with biopsy-proven coeliac disease were evaluated by sonographic assessment. Ten of them had presented with unusual clinical features such as acute abdomen and underwent sonography as the first diagnostic procedure. RESULTS: Various sonographic anomalies were observed: abdominal fluid in 76%, hyperperistalsis in 82%, pericardial effusion in 47% and unusual appearance of the small bowel wall in 94%. CONCLUSION: Although sonography cannot replace intestinal biopsy, awareness of the sonographic anomalies associated with coeliac disease in children can lead to a quicker diagnosis and prompt introduction of adequate therapy. It should be performed as a part of the diagnostic workup in infants who fail to thrive.

Abdomen, Acute↗
PubMed1996

[Detection of perfusion of kidney transplants. Comparison between color-coded and amplitude-coded Doppler ultrasound].

OBJECTIVE: To evaluate the efficiency of colour Doppler energy (CDE) in comparison to conventional colour Doppler sonography (CDI) in the detection of renal blood flow signals in asymptomatic patients after renal transplantation. SUBJECTS AND METHODS: Fifteen asymptomatic volunteer patients after renal transplantation were examined with CDI and CDE. The examination parameters were kept constant; only the Doppler-receiver gain was varied. Assessment and comparison of blood flow signals were obtained with a self defined score system. RESULTS: CDI showed Doppler signals in the main stem vessels, segmental and interlobar vessels in all patients; in the arcuate arteries blood flow signals were detected in only 11 of 15 patients. There was no Doppler signal in peripherally located medullary and cortical vessels. CDE showed blood flow signals in the main stem, segmental and interlobar vessels and additionally in the arcuate, interlobular and medullary as well as in the cortical vessels in all patients. CONCLUSION: CDE is more sensitive than CDI and improves the detection of blood flow signals in peripheral medullary and cortical vessels of renal transplants.

Adult↗
PubMed1996

In vivo three-dimensional sonographic measurement of organ volume: validation in the urinary bladder.

The purpose of this study was to assess the accuracy of in vivo measurement of organ volume using 3DUS and compare the results to 2D sonographic methods using the urinary bladder as the target organ and voided urine volume for validation. Fifty normal volunteers were studied. 2D volume measurements were based on length, width, and depth data and assumed a regular geometric model. 3D volume measurements were based on masked slices with the voxels integrated over the entire bladder. Voided urine volumes ranged from 35 ml to 701 ml. Residual urine volume was present in 48% of the subjects and ranged from 1% to 14% of the voided volume. 2D volume estimates for all 50 subjects had a mean absolute value of the error of 27.5% +/- 17.8%. 3D volume measurements had a mean absolute value of the error of 4.3% +/- 3.7% (transverse) and 5.6% +/- 3.8% (longitudinal). 3DUS provided more accurate volume measurements than 2DUS, particularly for irregularly shaped organs.

Adolescent↗