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Biomedical subjects

A Piepsz

Publications and source records attributed to A Piepsz.

At least 19 recordsLinked to original sources
PubMed1992

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.

Child↗
PubMed1992

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.

Acute Disease↗
PubMed1992

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.

Algorithms↗
PubMed1992

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.

Adolescent↗
PubMed1991

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.

Child↗
PubMed1991

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.

Adult↗
PubMed1991

Estimation of glomerular filtration rate in infants and in children using a single-plasma sample method.

This work was undertaken to look for distribution volume-plasma clearance converting equations(s) that can be used to estimate glomerular filtration rate (GFR) in children. GFR calculated using the two-blood sample slope-intercept method was used for comparison. It was shown that the 2-hr distribution volume and the two-blood sample clearance were closely related. For all the age groups, the coefficient of correlation between these two parameters was high (range: 0.95 to 0.99) and the s.e.e. was low (range 0.76-3.86 ml/min). It was also shown that a linear equation (GFR = 2,602 V120-0,273) could be used to convert the two hour distribution volume into an accurate estimate of two-blood sample GFR whatever the age of the patient. The use of the single-sample technique for measuring GFR in children is therefore recommendable.

Adolescent↗
PubMed1991

Normative data for lumbar spine bone mineral content in children: influence of age, height, weight, and pubertal stage.

In 136 normal growing children between the ages of 1 and 18 yr, bone mineral content (BMC) at the level of the lumbar spine (L2-L4) was determined with a commercial dual-photon absorptiometer. BMC was calculated as BML (BMC per unit length) and BMD (BMC per unit surface). The mean lumbar spine BML of the studied children (2.53 +/- 0.86 gHA/cm) was significantly lower than the spinal mineral content of adults (4.26 +/- 0.57 gHA/cm). No sex difference existed in lumbar spine BMC. BML as well as BMD were highly dependent on age, body height, and body weight. During the prepubertal years, BML and BMD increased in a fairly rectilinear pattern. During puberty, BMC increased more rapidly: 40% for BMD and 77% for BML. For the entire group, the increase in BMC with age, height, and weight was best predicted by an exponential regression line analysis.

Absorptiometry, Photon↗
PubMed1990

A radiopharmaceuticals schedule for imaging in paediatrics. Paediatric Task Group European Association Nuclear Medicine.

There is no standard schedule for the amounts of radiopharmaceutical administered to children at present. Various alternative methods are currently in practice, all with some support from the literature. Optimization of the amount of radiopharmaceutical to be administered is discussed in relation to the radiation burden of such an examination. The Paediatric Task Group of the European Association of Nuclear Medicine has investigated the current situation and now suggests a method for standardization of administered amounts of radiopharmaceutical in paediatrics. The fraction of the adult amount of radiopharmaceutical to be administered should be calculated from the child's body weight according to the accompanying table. In small infants, the minimum amount of a radiopharmaceutical is discussed and suggested amounts to be administered are presented.

Body Weight↗
PubMed1990

99mTc-DMSA scintigraphy in acute urinary tract infection in children.

24 children with symptomatic urinary tract infection (UTI) underwent systematically ultrasound studies (US) and 99mTc-DMSA renal scans. Among the 15 patients considered as acute pyelonephritis (APN) on clinical grounds, the scan was abnormal in 12 cases, in contrast with only 1 abnormal scan in the clinical subgroup of the lower UTI. Among the 10 abnormal scans that were repeated later on, 6 did completely normalize. US showed only once a parenchymal appearance suggestive for APN. Our findings suggest that the DMSA scan has to be considered at present as the most sensitive imaging technique for the detection of APN.

Acute Disease↗
PubMed1990

Consolidating the role of *I-MIBG-scintigraphy in childhood neuroblastoma: five years of clinical experience.

In recent years, *I-MIBG (*I-metaiodobenzylguanidine), which is transported and stored in the chromaffin cells, has been shown to allow good visualization of neuroblastomas in children. This paper deals with 30 *I-MIBG-scans performed in 20 children: 16 with neuroblastoma, 3 with retinoblastoma, and 1 with a malignant paraganglioma. A high detection rate was found for both primary and secondary sites of neuroblastoma. *I-MIBG was generally superior to 99mTc-MDP bone scintigraphy in the detection of bone metastases. Our experience illustrates the unique place of *I-MIBG-scintigraphy compared with other imaging techniques: it makes it possible to define the nature of the tumour, particularly in cases with normal catecholamine levels; to establish how extensive the lesions are at the time of diagnosis; and to confirm complete remission. No abnormal *I-MIBG uptake was noted in the 3 cases of retinoblastoma.

3-Iodobenzylguanidine↗
PubMed1990

Unusual Tc-99m MDP and I-123 MIBG images in focal pyelonephritis.

A 6-year-old boy presented with an inflammatory syndrome. Because Tc-99m MDP bone scintigraphy revealed increased tracer uptake at the upper pole of the right kidney, further studies were oriented towards a diagnosis of renal or adrenal pathology. I-123 metaiodobenzylguanidine (MIBG) accumulated at the site of the abnormal MDP uptake. The diagnosis of neuroblastoma or allied disorder was excluded on the basis of other investigations and further evaluation, suggesting that the MIBG uptake was a false-positive. Findings on clinical imaging, laboratory findings, Tc-99m DMSA imaging, sonography, and CT scanning were highly suggestive of acute focal pyelonephritis.

3-Iodobenzylguanidine↗
PubMed1990

Caustic ingestion and esophageal function.

The aim of the present study was to investigate esophageal motor function by means of krypton-81m esophageal transit scintigraphy and to compare the results with the functional and morphological data obtained by means of triple lumen manometry and endoscopy. In acute and subacute stages of the disease, all clinical, anatomical, and functional parameters were in good agreement, revealing significant impairment. In chronic stages, the severity of the dysphagia was not correlated to the importance of the residual stenosis. Conversely, 81mKr esophageal transit and manometric's findings were in good agreement with the clinical symptoms, during the entire follow-up period ranging between 3 months to 7 years. The 81mKr test is undoubtedly the easiest and probably the most physiological technique currently available for long-term functional evaluation of caustic esophagitis.

Accidents, Home↗
PubMed1990

Cerebral palsy: initial experience with Tc-99m HMPAO SPECT of the brain.

The outlook for children with cerebral palsy is determined by the severity of motor problems and the presence of associated disabilities, in which early detection remains a medical challenge. The authors studied 13 children (aged 13 months to 12 years) with cerebral palsy by means of single photon emission computed tomography (SPECT) of the brain with technetium-99m hexamethylpropyleneamineoxime (HMPAO). In all children with hemiplegia, SPECT demonstrated hypoperfusion in the hemisphere contralateral to the motor deficit. SPECT demonstrated normal findings in patients with mild diplegia; bilateral hypoperfusion in the superior motor cortex in patients with moderate di- or tetraplegia; and bilateral reduction of perfusion in the superior motor, inferior motor, prefrontal, and parietal cortices in patients with severe di- or tetraplegia. Results suggest that Tc-99m HMPAO SPECT of the brain is a valuable complementary tool for thorough neurologic assessment in cerebral palsy.

Brain↗