Biomedical subjects
A Piepsz
Publications and source records attributed to A Piepsz.
Camurati-Engelmann disease: contribution of bone scintigraphy to genetic counseling.
Progressive diaphyseal dysplasia (Camurati-Engelmann disease) is a rare hereditary disorder of bone characterized by progressive, bilaterally symmetrical diaphyseal sclerosis of the long bones. Severely affected patients show muscle weakness, waddling gait and severe pain in the extremities. However, clinical and radiological investigations in families with Camurati-Engelmann disease demonstrate a wide variability in expression of the manifestations. Asymptomatic patients were in several instances diagnosed only after radiologic screening of relatives. Although considered an autosomal dominant disorder, families are described where neither clinical nor radiological manifestations can be demonstrated in direct ancestors of patients. Combining roentgenographic examination with bone scintigraphy seems therefore necessary in confirming or ruling out progressive diaphyseal dysplasia in each family member.
Legg-Perthes disease: partial or total loss of femoral head? Contribution of SPECT images.
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[Measurements of renal clearances with radioisotopes].
This paper analyzes the radioisotopic methods allowing the estimation of renal function. The advantages and the drawbacks of the method are presented, as well as the specific characteristics related to the child. Finally, these methods, and particularly those related to the measurement of glomerular filtration, are integrated in a comprehensive approach of the paediatric examinations.
Comparison of technetium-99m MAG3 kit formulations in Europe and the USA.
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Determination of the technetium-99m mercaptoacetyltriglycine plasma clearance in children by means of a single blood sample: a multicentre study. The Paediatric Task Group of the EANM.
A multicentre European study was undertaken in order to determine a reasonable algorithm allowing the determination of overall technetium-99m mercaptoacetyltriglycine clearance using a single blood sample. Employing multiple blood sample clearance as a reference method, it was shown that an acceptable estimation of the MAG3 renal clearance could be obtained using a blood sample taken at any time between 30 and 40 min after tracer injection. After correction for body surface area, comparison of clearance determined using (a) the single blood sample and (b) the multiple blood samples provided a coefficient of correlation of 0.949 and an SEE of 27 ml/min. This algorithm is valid for clearance values higher than 100 ml/min/1.73 m2 and for children older than 1 year of age.
Captopril radionuclide test in renovascular hypertension: a European multicentre study. European Multicentre Study Group.
The diagnostic work-up of renovascular hypertension is still controversial. The efficacy of renal scintigraphy with technetium-99m diethylene triamine pentaacetate (DTPA) before and after captopril (scintigraphic captopril test) was evaluated in a multicentre study. All 380 hypertensive patients in the study underwent renal arteriography; 125 had renal arterial stenosis > or = 70%, and 54 had a technically successful intervention to correct the stenosis. The post-captopril study had a sensitivity of 93% and a specificity of 100% for predicting blood pressure response to intervention, if renal function was normal and a combination of quantitative parameters was applied (individual kidney uptake index < 40%, time to peak activity < 2 min or > 10 min). In the entire population renal artery stenosis > or = 70% was detected with a sensitivity of 83% and a specificity of 93% if renal function was normal. In patients with abnormal renal function the performance of the test was worse, owing to a lower specificity which could be increased by using only time parameters. The performance of the test was optimal when the post-captopril findings were examined; no improvement was achieved by evaluation of the changes induced by captopril from the baseline. The test can thus be simplified by performing only a post-captopril study for routine use: a negative test would exclude a curable form of renovascular hypertension in > 80% and a positive test would predict it in > 90% of the patients selected for suspicion of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)
Renal function abnormalities after ifosfamide treatment in children.
Renal function was evaluated in 12 children (aged 2.5-17.5 years) who received ifosfamide as part of their chemotherapy for different malignancies. A blood and urine analysis evaluating renal glomerular and tubular function and an isotopic determination of glomerular filtration were carried out four months or later after treatment had been stopped. Three patients had several biochemical abnormalities suggesting a significant degree of proximal renal dysfunction (increased urinary excretion of calcium, glucose, beta 2-microglobulin, amino acids (three patients) and decreased tubular reabsorption of phosphate (one patient)). The tubular dysfunction in these patients was associated with a diminished glomerular filtration. These patients could be characterized by their younger age at treatment and a higher dose of ifosfamide received if calculated per kg body weight.
Low serum bone gamma-carboxyglutamic acid protein concentrations in patients with cystic fibrosis: correlation with hormonal parameters and bone mineral density.
In 31 children and adolescents with cystic fibrosis (CF), whose bone mineral density (BMD) was determined at the level of the lumbar spine, serum bone gamma-carboxyglutamine acid (GLA) protein (BGP) was measured. A standard radioimmunoassay method gave for the studied CF population a median serum BGP concentration of 9 micrograms/l (range: 0.8-18.6) which corresponds to a median Z-score for age of -1.72 (range: -3.3 to +0.04). Thirteen patients presented a BGP concentration lower than 2 standard deviations (SD) under the mean for age. These patients did not differ from the others by their circulating thyroxine, triiodothyronine, 25-hydroxyvitamin D or parathyroid hormone levels. The lowering of the BGP concentration was neither related to the growth velocity nor to the severity of the lung disease, as assessed by lung scintigraphy. Six patients with a decreased BMD (< 2 SD under mean for age) were found. Five of them had also a decreased BGP concentration. In conclusion, decreased serum BGP concentration was found in 42% of the studied CF patients and could not be related to hormonal abnormalities. Serum BGP had a low specificity (72%) in predicting osteopenia in young CF patients.
[Technetium 99m labeled dimercaptosuccinic acid (99m Tc-DMSA) scintigraphy in the diagnosis and follow-up of urinary infections in children].
BACKGROUND: The site of a urinary tract infection (UTI) is located by clinical findings plus imaging techniques. Renal imaging with technetium 99mTc-dimercaptosuccinic acid (99mTc-DMSA) has shown promise but its efficacy for detecting acute pyelonephritis is still debated as is its ability to differentiate between acute, potentially curable disease and scarring, definitive changes. PATIENTS AND METHODS: The files of all the 166 patients that underwent one or two (32 patients) 99mTc-DMSA imaging sessions for UTI in 1989 and 1990 in our department were analysed. The results of this technique were compared with the clinical and laboratory data and with those of other imaging techniques (ultrasonography and retrograde voiding cystourethrogram). The patients (92 girls and 74 boys, mean age: 5 years, range 15 days-17 years) were assigned to one of 3 categories: 1) acute pyelonephritis (27 patients), 2) low UTI (60 patients) and 3) uncertain UTI (79 patients), on the basis of the clinical and laboratory data. RESULTS: The first 99mTc-DMSA imaging was normal in 110 children; changes were unilateral in 45 and bilateral in 11 children. Images suggesting either acute or chronic changes were observed respectively in 19 and 48 children. 4 of the 7 acute changes were normalized on the second radioisotope scanning while 2 became worse; 19 of the 23 chronic changes were unchanged at the second scanning. Radioisotope scanning changes were seen in 81% of the patients classified as acute pyelonephritis and in only 27% of those with lower UTI. Reflux was detected in 56% of abnormal kidneys and in 36% of normal kidneys. The results of radioisotope scanning and ultrasound scan findings were not correlated in 24 patients (19 only abnormal radioisotope imaging, 5 only abnormal ultrasound scan). CONCLUSIONS: DMSA scans are useful for investigating and following UTI. They help to distinguish acute pyelonephritis and lower UTI. It is a reliable method of detecting structural abnormalities and identifying children at risk of progressive renal damage.
Prediction of cerebral palsy in high-risk neonates: a technetium-99m-HMPAO SPECT study.
In infants who have experienced prenatal or perinatal injury, it is often difficult, on the basis of clinical examination and conventional investigations (electroencephalogram, cranial ultrasound scan), to diagnose those with brain damage and to predict the type and the severity of subsequent neurological handicaps. We investigated the predictive value of 99mTc-HMPAO brain SPECT performed in the first weeks of life in high-risk neonates. Right-left asymmetries in tracer uptake had no predictive value, regardless of their localization or severity. On the other hand, a change in antero-posterior rCBF distribution was found in 7/10 of neonates with adverse outcome (death, major neurological sequelae) and in none of the 78 neonates with no major motor neurological sequelae. Compared to conventional investigations, 99mTc-HMPAO brain SPECT did not provide additional predictive information when neurological examination, electroencephalogram and cranial ultrasonography were all normal or all abnormal. Conversely, in the 30 patients with anomalies on one or two of the above investigations, SPECT showed an abnormal antero-posterior pattern in 4/6 neonates with major neurological sequelae and no change in the antero-posterior rCBF distribution in the 24 infants who developed normally. In conclusion, our results suggest that 99mTc-HMPAO brain SPECT, when performed in the first weeks of life, can be useful in high-risk neonates to predict occurrence of major neurological handicaps. Because of the relative invasive character of HMPAO scan in neonates and the overall accuracy of the noninvasive tests, radionuclide examination should not be performed in every high-risk neonate. According to our results, 99mTc-HMPAO brain SPECT might be indicated in those children where noncongruent results were obtained with conventional studies.
Evaluation of reflux episodes during simultaneous esophageal pH monitoring and gastroesophageal reflux scintigraphy in children.
Gastroesophageal pH monitoring and reflux scintigraphy were simultaneously performed in 65 children, who were being investigated for suspected gastroesophageal reflux disease. The aim of the study was to compare, peak per peak, the information provided by the two techniques during a 1-h simultaneous-recording period. During this period, 123 reflux episodes were recorded with both techniques, but only six occurred simultaneously. Significantly more reflux episodes were recorded on scintigraphy (n = 88; p less than 0.05), particularly during the first half-hour period (n = 62), if compared with the number of pH drops greater than 1 unit, even at pH levels higher than 4 (n = 41; p less than 0.05). It is concluded that the two techniques explore differently the reflux phenomenon.
Replacing 99Tcm-DMSA for renal imaging?
We have tried to evaluate the usefulness of an early 99Tcm-MAG3 image, obtained during the second minute after injection of the tracer, in predicting the renal alterations seen on a 99Tcm-DMSA scintigraph, in children clinically suspected of pyelonephritis. It appears that the accuracy of the MAG3 image is population dependent: when, in most of the patients of a study group, DMSA scintigraphy is either normal or very abnormal, the MAG3 image will correctly reflect the DMSA scintigraph. However, when the DMSA alterations are less pronounced, the early MAG3 image will miss the lesions in about 50% of the cases.
Clinical measurement of renal clearance.
The importance of renal clearance in uronephrology has motivated the continuous reassessment of well-established methods and the relentless search for better techniques. Concerning radionuclide methods, data in the current literature confirm the validity of the simplified one-compartment model or the empirical single-sample method for renal clearance measurement, and new algorithms have been described to broaden the application of the techniques to the pediatric population. Based on the same principles, accurate measurement of renal clearance can also be obtained using contrast agents. Using the technique for determination of the glomerular filtration rate during radiographic contrast examination is recommendable. However, potential adverse effects of the contrast substances should be compared with those of other methods before using this technique for measuring renal clearance without scheduled contrast roentgenographic examination. Controversy remains concerning the validity of predicting glomerular filtration rate from plasma creatinine. Although the predicted clearance is correlated with reference clearance, analysis of individual results reveals that important differences of up to 50 mL/min frequently occur.
Detection of bilateral and symmetrical anomalies in technetium-99m-HMPAO brain SPECT studies.
The detection of bilateral and symmetrical regional cerebral blood flow (rCBF) abnormalities requires knowledge of the antero-posterior rCBF distribution in normal subjects of all age groups. These data are very difficult to obtain in children for ethical reasons and in older subjects because of the necessity of recruiting a large number of healthy volunteers from each age group. Therefore, to obtain normal values of antero-posterior rCBF distribution, we have retrospectively selected a group of patients with a low probability of having cerebral lesions, whose 99mTc-HMPAO brain SPECT studies were analyzed semiquantitatively. Cerebellum/mean cerebral cortex index when compared to young adults was higher in the neonatal period, slightly lower between 2 mo and 15 yr, and more or less identical after 15 yr. Cortico/occipital indexes exhibit considerable changes during the first year of life due to important differences in maturation timing of cerebral cortical areas. After 1 yr, all cerebral cortical areas approximately displayed a parallel evolution. A slight increase in fronto/occipital and temporo/occipital indexes was, however, still observed during childhood, while in elderly subjects there was a trend towards a decrease in all cortico/occipital indexes (particularly in prefrontal and motor areas). Changes that occurred after 1 yr were, however, usually smaller than interindividual variation. Despite the large range of "normal" values, the antero-posterior analysis could be useful in various neurologic disorders, because it allows detection of symmetrical rCBF anomalies undiagnosed by the right-left analysis.
Procedures of choice in renal nuclear medicine.
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Paediatric nuclear medicine.
Until the 1980s no serious attempts were made to develop paediatric nuclear medicine, as for various reasons many centres were reluctant to perform radionuclide examinations on children. Then two books were published on paediatric nuclear medicine in 1984 and 1985, respectively. In 1987, a group of physicians formed an informal club of paediatricians and nuclear medicine specialists in an effort to improve the relationship and cooperation between these specialties. Carrying out nuclear medicine examinations on children requires a completely different approach than on adults. Suggestions are made and tips given, and the specific problems involved are discussed in detail.
Technetium 99m mercaptoacetyltriglycine gamma camera clearance calculations: methodological problems.
Major sources of errors in the gamma-camera methods for the calculation of renal clearance are the accuracy of background correction for obtaining the true renal time-activity curve and the validity of the externally recorded pre-cordial activity as an estimate of the plasmatic time-activity curve. With technetium 99m mercaptoacetyltriglycine (99mTc-MAG3), because of its high protein plasma binding, one could expect minimal extravascular diffusion and hence a more accurate externally detected plasmatic curve. The high extraction rate should reduce the influence of the background, but, on the other hand, the effect of hepatobiliary excretion on the calculation of renal clearance might be significant. Our results suggest that the hepatobiliary excretion of 99mTc-MAG3 does not influence the gamma-camera renal clearance determination, even in patients with low renal function. However, the pre-cordial curve does not reflect accurately the plasmatic disappearance curve; its calibration with a single plasma sample taken at the 20th min is responsible for significant errors, probably because of an unfavourable ratio between the intravascular and extravascular activities at the 20th min.