Search PubMed⌕ Search

Biomedical subjects

W Mortensson

Publications and source records attributed to W Mortensson.

At least 19 recordsLinked to original sources
PubMed1999

Estimating the effective dose to children undergoing heart investigations--a phantom study.

The aim of the investigation was to assess the conversion factor (F) for derivation of effective dose from measured dose-area product (DAP) during radiological examination of congenital heart diseases. Two anthropomorphic phantoms corresponding to a 1-year-old and a 5-year-old child were irradiated at several projections to imitate irradiation conditions at heart examinations. Organ doses were measured using thermoluminescent dosimeters for calculation of mean organ doses and effective dose according to ICRP. DAP values were measured simultaneously. The conversion factor (F) was calculated from the ratio of effective dose (mSv) to DAP value (Gy cm2). The conversion factor (F) correlated strongly to the size of the phantom but less to the irradiation projection. However, at major beam angulation and at lateral projection F deviated note-worthily from that obtained at true or slightly angulated frontal views. Effective dose can therefore be estimated from the DAP values at heart investigation using two different F values. The following values are recommended for PA and lateral view respectively: for children weighing 7-11 kg, 1.8 and 1.4; for children weighing 15-26 kg 0.9 and 0.7.

Age Factors↗
PubMed1997

Diagnosis of intracranial lesions in very-low-birthweight infants by ultrasound: incidence and association with potential risk factors.

This study was designed to determine the frequencies of germinal matrix and ventricular haemorrhages as well as lesions in the white matter diagnosed by ultrasonography. In subsequent studies the effects of perinatal brain lesions on the cognitive and motor development of preterm children will be presented. Lesions of the white matter are probably more damaging than intraventricular and subependymal bleeds. Therefore, a modified classification of the lesions was used, clearly separating bleeds from white matter pathology. The study includes 291 infants with a body weight of < or = 1500 g consecutively admitted to the neonatal intensive-case unit at Karolinska Hospital from 1988 to 1993. Fifty-four (18.9%) died before 6 months. Two hundred and sixty-three infants were examined using ultrasound. Pathology due to bleeding was classified into three grades (B1-3) similar to Papile's first three grades. Pathology in periventricular white matter was classified into four groups (W1-4): W1 = subtle and We = distinctive white matter echodensities; W3 = cyst formation; W4 = large, intense echodensity. Forty-nine patients had abnormalities in the periventricular white matter (15 W1, 12 W2, 11 W3 and 11 W4) and 58 had subependymal (B1 = 29) or ventricular bleeding without (B2 = 13) or with dilatation (B3 = 16). Ventilator treatment was significantly associated with both B and W lesions. Low gestational age, low birthweight, small for gestational age, pre-eclampsia and caesarean section were significantly associated with B lesions whereas asphyxia, surfactant treatment, male patient sex and outborn were associate with W lesions; b 1-3 and W 1-4 lesions were thus partly associated with different potential risk factors. The pre- and perinatal potential risk factors could only partly explain the variance in the frequency of B and W lesions, indicating that there are yet unidentified risk factors for intracranial ultrasonographic pathology.

Cerebral Hemorrhage↗
PubMed1996

Comparison of absorbed radiation doses in barium and air enema reduction of intussusception: a phantom study.

OBJECTIVE: We assessed the relative radiation load in patients undergoing hydrostatic and pneumatic reduction of childhood intussusception. MATERIALS AND METHODS: In a phantom study we simulated two situations occurring during reduction of intussusception. The absorbed radiation dose was measured at several positions in the phantom using either barium sulphate (BaSO4) or air in the simulated reduction, combined with either automatic exposure control (AEC) or constant exposure rate (CER) at fluoroscopy. From these values the mean absorbed dose was calculated for different depth compartments within the phantom. RESULTS: In the barium study the mean absorbed dose averaged over the total irradiated volume was 14-23 % lower when CER was used instead of AEC; in the air study the dose was 35-43 % lower when AEC was used instead of CER. The combination of air and AEC provided the lowest mean absorbed dose in the tissue. The barium enema created a low-radiation zone, which might be utilized for protecting radiation sensitive tissue. CONCLUSION: The use of BaSO4 or air in reduction of intussusception requires the proper combination with CER and AEC, respectively, to minimize the radiation load to the patient; the lowest radiation load is obtained by using air and AEC.

Abdomen↗
PubMed1995

Radiographic patterns and viral studies in childhood pneumonia at various ages.

We aimed at evaluating the relationship between microbial etiology and chest radiograph appearance in various types of pneumonia. In a prospective study, the radiographic findings in 479 cases of acute pneumonia in children were compared with viral etiology and growth of potential bacterial pathogens in nasopharyngeal secretion. As the basis for viral etiology was most conclusive, the material was here classified according to the viral findings. The patients were divided into three age groups: 0-2, 3-5 and 6-15 years. The chest radiograms were analyzed blindly for the presence of hyperinflation and interstitial, alveolar and mixed interstitial-alveolar infiltrates. There was a statistically significant relationship between low age and occurrence of hyperinflation and interstitial infiltrates, and between high age and alveolar infiltrates. No unequivocal relationship was found between type of infiltrates or presence of atelectasis and proven viral etiology. We conclude that chest radiographs are not a useful indicator of microbial etiology in childhood pneumonia.

Acute Disease↗
PubMed1994

Image quality and safety in pediatric urography using an ionic and a non-ionic iodinated contrast agent.

The safety and diagnostic efficacy of the new non-ionic, monomeric contrast medium iopentol (Imagopaque) were evaluated and compared with those of the ionic medium metrizoate (Isopaque), in urography in children in a randomized, double-blind, parallel study. The trial comprised 59 children aged from 3 months to 8 years; children with predefined risk factors were not included. The difference in attenuation between the renal and perirenal tissue, assessed from film density measurements, was chosen as the main variable. Diagnostic efficacy was also evaluated subjectively from demarcation of the kidney and the pelvic structures. There was no statistically significant difference between the groups in the diagnostic efficacy. Serious adverse events did not occur in either group. Mild to moderate, transient adverse events were significantly less frequent in the iopentol group than in the metrizoate group, but in no case was medical treatment required. There were no changes or trends toward changes of clinical importance in either group, in serum chemistry variables measured in blood samples taken 2 min after injection of contrast medium compared to baseline values.

Child↗
PubMed1994

Radiation exposure to children in diagnosing and at hydrostatic reduction of intussusception.

The energy imparted to the children in diagnosing and hydrostatic reduction of intussusception was measured in 45 children by means of an area-dose measurement device and the mean absorbed dose was estimated. The device was provided with data on tube kVp, mAs and shutter positions and the results were presented as dGy x cm2. The device had been calibrated against a 30 cm3 ionisation chamber at the relevant kVp range. The median energy imparted and mean absorbed dose were 10.8 mJ and 0.94 mGy, respectively. 70% of the total dose was delivered during fluoroscopy. The complex irradiation situation with varying field collimation, tube voltage and amount of photon absorbing barium sulphate in the intestines renders organ dose and hazards estimations less reliable. However, even leaving the radiation shielding effect of the barium sulphate out, the radiation load is justifiable for a combined diagnostic and interventional procedure.

Child, Preschool↗
PubMed1993

Correlations between radiological and cytological findings in early development of bronchopulmonary dysplasia.

Sequential chest radiographs from 40 newborn infants requiring assisted ventilation for respiratory distress syndrome or other conditions were evaluated with a new scoring system aiming at identifying abnormal expansion patterns and interstitial infiltrates representing an early stage of bronchopulmonary dysplasia (BPD). Age at examination ranged from 3 to 23 days. Tracheal effluent samples obtained from the babies during the same period of observation were examined cytologically for evidence of regenerating airway epithelium with squamous metaplasia, indicating BPD. According to the radiological scoring system 24 babies (60%) developed BPD, first diagnosed at a median age of 9 days. By cytological criteria 20 babies (50%) developed BPD, first diagnosed at a median age of 10.5 days. The results from radiological and cytological diagnosis of BPD were concordant in 16 babies (P < 0.05 by chi-square test). Using oxygen dependency at the age of 28 days as evidence of established BPD, the radiological scoring system alone had a sensitivity of 93% and a specificity of 53%. The corresponding figures for cytological assessment alone were 73% and 58%, respectively. By combining radiological and cytological findings, values for sensitivity and specificity were 67% and 68%, respectively.

Bronchopulmonary Dysplasia↗
PubMed1992

Contrast medium injected into juvenile bone cysts to analyze interior morphology and guide intracavity corticosteroid treatment.

In connection with treating juvenile bone cysts with intracavital corticosteroid injections, the interior cyst anatomy was analyzed at cystography in 13 children aged 4 to 15 years. Only 4 children had a true unicameral cyst; the others had 2 or more cysts or had compartments with free or restricted communication to the main cyst. Cysts and compartments which had not been reached by steroids may continue to grow. Optimum treatment may therefore require injections at different sites guided by cystography. Neither conventional criteria of cyst activity nor repeated bone scintigraphy 3 months after treatment could predict whether the treatment would lead to final healing.

Adolescent↗
PubMed1991

Left-side dominance of upper extremity fracture in children.

In 148 children who had sustained trauma to the upper extremities from falls, fractures were twice as common on the left as on the right side. This seemed to be due to the childrens' preferential use of the left hand to parry the fall even when both hands were free and because the left arm seemed to be more easily broken than the right arm during trauma.

Adolescent↗
PubMed1990

Neonatal skeletal maturation in congenital hypothyroidism and its prognostic value for psychomotor development at 3 years in patients treated early.

Neonatal skeletal maturation was assessed by different methods based on the bone centres in the knee and ankle region in 46 infants with true-positive (patients) and 17 infants with false-positive screening tests (controls). The patients and controls did not differ in mean age at X-ray examination and age at the start of treatment (14.5 +/- 5.7 days). One of the methods used to score the size of femoral and tibial epiphyses was just as good as the other ones tested, but has the advantage of being the easiest to use and therefore clinically most suitable. Skeletal maturity assessed by this method correlated best with serum T4 (r = 0.62, p less than 0.01). Griffiths tests were performed in 37 of the 46 patients at 28-48 months of life. The best correlation obtained between neonatal skeletal maturity and Griffiths global developmental quotient at 3 years of age was r = 0.58 (p less than 0.001). Although statistically significant, it was too weak to be of clinical value in identifying individual patients at risk. We conclude that an assessment of skeletal maturation is not useful for the prognosis of psychomotor development in individual patients with congenital hypothyroidism receiving treatment within the first 2 weeks of life.

Age Determination by Skeleton↗
PubMed1990

The role of bone scintigraphy in predicting femoral head collapse following cervical fractures in children.

Bone scintigraphy was performed before or after osteosynthesis or both in 11 children aged 9 to 14 years with femoral neck fractures. The role of bone scintigraphy in predicting development of femoral head necrosis with subsequent collapse was studied. Scintigraphy was not a useful study for this purpose. The explanation of this may be that reposition and osteosynthesis jeopardize the blood supply to the femoral head and invalidates the findings at the pre-operative scan. The childhood femoral head also has a strong potential for revascularization and complete reconstruction of the necrotic bone.

Child↗
PubMed1989

Potential of early chest roentgen examination in ventilator treated newborn infants to predict future lung function and disease.

The potentially of early chest X-ray to predict the risk of lung function abnormalities was studied prospectively in 40 preterm ventilator treated infants in a 8-10-year follow-up investigation. According to the findings at chest X-ray 3 to 10 days after completed ventilator treatment the infants were divided into 3 groups considered to represent increasing risk and severity of lung damage: 1) normal findings, 2) interstitial parenchymal abnormalities exclusively or 3) in combination with local or general hyperinflation. Lung function tests and chest x-ray were performed at the age of 8 to 10 years. A correlation was found between the findings at the early chest roentgen examination and the risk of abnormal lung function at the follow-up. Occurrence of focal or general hyperinflation or both were associated with a greater risk of airway obstruction. Infants with only interstitial abnormalities were, however, at a higher risk than those with normal chest examination to develop general hyperinflation and increased air way obstruction.

Bronchopulmonary Dysplasia↗
PubMed1989

Lung function eight years after neonatal ventilation.

Forty children who had had artificial ventilation during the neonatal period were studied at the age of 8-10 years with spirometry, the nitrogen washout test, bicycle exercise test, pulse oximetry, electrocardiogram, vectorcardiogram, and chest radiography. The median gestational age at birth was 29 weeks, and the median birth weight was 1310 g. Hyaline membrane disease was the indication for neonatal ventilation in 25 children. Bronchopulmonary dysplasia was diagnosed from radiographs in 11 infants (27%). Airway obstruction was observed in 10 of 11 children who had had bronchopulmonary dysplasia and in nine of 29 children who had not. After inhalation of terbutaline, the forced expiratory volume in one second (FEV1) was significantly increased. General hyperinflation was found in 16 of 17 children with abnormal chest radiographs (eight who had had bronchopulmonary dysplasia and nine who had not). Functional residual capacity was significantly higher in children with abnormal radiographs. Each child had a normal maximum working capacity and a normal electrocardiogram, and all but two had normal vectorcardiograms. Oxygen saturation at maximum work load decreased significantly in both groups of children. The risk of future respiratory problems calls for further follow up of lung function and chest radiography.

Electrocardiography↗
PubMed1987

Severe neonatal respiratory distress syndrome treated with the isolated phospholipid fraction of natural surfactant.

Ten newborn infants (795-1680 g) with severe respiratory distress syndrome (RDS) were treated with the isolated phospholipid fraction of bovine or porcine surfactant, which was administered via the airways (dose 200 mg/kg), at a median age of 10.5 h. Before receiving surfactant, all the infants were on artificial ventilation (FiO2 0.6-1.0). Within 2 h after surfactant replacement, the arterial-to-alveolar PO2 ratio increased from 0.1 to 0.35. There was a concomitant improvement in lung aeration on the chest roentgenograms and a significant reduction in the right-to-left shunt. Four patients died of cerebral hemorrhage; two of them also had a patent ductus arteriosus. One surviving infant developed bronchopulmonary dysplasia, and another succumbed 8 months later to the sudden infant death syndrome. No antibodies against surfactant were detected in the sera of the survivors. Since our results show a significant improvement in lung function after replacement therapy, the efficacy of this new surfactant preparation should be further tested in randomized clinical trials.

Chromatography, Gel↗