Biomedical subjects
Publications and source records attributed to A Piepsz.
Repetitive quantitative renal extraction studies of 99Tcm-MAG 3, performed in nine rats, demonstrated excellent reproducibility of successive measurements. These results are better than with 99Tcm-DTPA, due to the higher renal extraction of the 99Tcm-MAG 3. The % of renal uptake 10 min after the injection was not influenced by the elapsed time between the end of the 99Tcm-MAG 3 preparation and its i.v. administration.
The application of regional cerebral blood flow (rCBF) study by means of lipophilic radiotracers and single photon emission computed (SPECT) devices in very young infants is hampered by the considerable changes of rCBF pattern as a result of the cerebral maturation process. In an attempt to determine the normal evolution of [123I]IMP SPECT pattern as a function of age, we retrospectively selected the studies of 30 babies with normal clinical examination, EEG and CT or ultrasound scans at time of SPECT. There was a marked predominance of the thalamic perfusion over cortical areas until the end of the second month. The distribution of regional cortical activity followed a strict sequence. The perfusion of both parietal and occipital areas was well-visualized around the 40th week of gestational age and thereafter rapidly rose, always, however, with a slight predominance of the parietal activity. At the opposite, frontal activity which remained scarcely recognizable up to the second month tremendously rose to present the adult-like pattern at the beginning of the second year. The rCBF changes described above are well in agreement with the behavioral evolution occurring during prime infancy.
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This study was designed to rate the clinical value of [123I]iodoamphetamine (IMP) or [99mTc] hexamethyl propylene amine oxyme (HM-PAO) brain single photon emission computed tomography (SPECT) in neonates, especially in those likely to develop cerebral palsy. The results showed that SPECT abnormalities were congruent in most cases with structural lesions demonstrated by ultrasonography. However, mild bilateral ventricular dilatation and bilateral subependymal porencephalic cysts diagnosed by ultrasound were not associated with an abnormal SPECT finding. In contrast, some cortical periventricular and sylvian lesions and all the parasagittal lesions well visualized in SPECT studies were not diagnosed by ultrasound scans. In neonates with subependymal and/or intraventricular hemorrhage the existence of a parenchymal abnormality was only diagnosed by SPECT. These results indicate that [123I]IMP or [99mTc]HM-PAO brain SPECT shows a potential clinical value as the neurodevelopmental outcome is clearly related to the site, the extent, and the number of cerebral lesions. Long-term clinical follow-up is, however, mandatory in order to define which SPECT abnormality is associated with neurologic deficit.
Congenital dysphasia is a developmental speech disorder not explained by deafness, phonation disorder, mental retardation, neurologic lesion, or psychiatric disease. The existence of brain lesions has often been postulated but conventional investigations fail to demonstrate any cerebral abnormality. By means of [99mTc]hexamethyl-propyleneamine oxime (HM-PAO) brain single photon emission computed tomography (SPECT) we have studied 14 children suffering from congenital dysphasia. The brain computed tomographic scan was normal in all cases. In two patients with expression impairment the SPECT study demonstrated a hypoperfusion in the inferior frontal convolution of the left hemisphere, involving the Broca's area. In nine of 12 patients with global dysphasia (deficits in both comprehension and expression), SPECT study showed two hypoperfused areas: an abnormality in the left temporoparietal region and a hypoactivity in the upper and middle areas of the right frontal lobe. These results suggest that congenital dysphasia could be due, like acquired aphasia, to specific impairment of the language cerebral areas and that brain SPECT studies with [99mTc]HM-PAO could be useful for a better comprehension of the physiopathology of these disorders.
We report two cases of primary lung tuberculosis in children with unusual perfusion ventilation scintigraphic patterns. In the first case, a mismatch in the right upper lobe suggests an elective compression of the bronchi by the mediastinal lymph nodes; in the second case, the total absence of ventilation and perfusion of the left lobe at scintigraphy illustrates the discrepancy sometimes encountered between chest x-ray and lung scintigraphy.
A 3-year-old girl with a complicated partial anomalous pulmonary venous return presented a scintigraphic pattern characterized by an absence of perfusion of the right lung, contrasting with normal ventilation.
A multicentre European study on foreign body inhalation has been organized by the Pediatric Task Force covering both the SNME and the ENMS. Among the 100 cases which could be collected in a 2 year period, about 40% of scintigraphic abnormalities were found 6 months after relief of the foreign body. The frequency of these defects was clearly related to the time interval between aspiration and removal. Factors like the localization of the foreign body and the site of the early scintigraphic defects could be related to the further scintigraphic outcome, but this could not be proven statistically. Similarly, the absence of bronchial tree inspection after removal of the foreign body seemed to be associated with more permanent scintigraphic lesions. Finally, it is obvious that a large number of patients demonstrated scintigraphic alterations 6 months or more after removal of the foreign body, although the chest X-rays were considered normal.
Cortical and whole kidney radionuclide transit parameters were studied in 16 patients who underwent a pyeloplasty for unilateral pelviureteral junction (PUJ) obstruction. As expected, the whole kidney mean transit time was found to be very sensitive but, due to the low specificity, not very helpful in the distinction between obstructed and nonobstructed kidneys. The cortical transit reflected, in some cases, the favorable surgical outcome. In other cases, however, it could not be considered as a reliable parameter of the clinical status, since it was found to be normal preoperatively and prolonged postoperatively in patients whose parenchymal function improved significantly after surgery and who had their clinical symptoms relieved.
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Fourteen children with various seizure disorders were studied using a cerebral blood flow tracer, 123I iodoamphetamine (0.05 mCi/kg), and single photon emission computed tomography (SPECT). In the five patients with radiological lesions, SPECT showed congruent or more extensive abnormalities. Five of the nine children with a normal scan on computed tomography had abnormal SPECT studies consisting of focal hypoperfusion, diffuse hemispheric hypoperfusion, multifocal and bilateral hypoperfusion, or focal hyperperfusion. A focal lesion seen on SPECT has been found in children with tonic-clonic seizures suggesting secondarily generalised seizures. Moreover the pattern seen on SPECT seemed to be related to the clinical status. An extensive impairment found on SPECT was associated with a poor evolution in terms of intellectual performance and seizure frequency. Conversely all children with a normal result on SPECT had less than two seizures per year and normal neurological and intellectual development.
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In this study the potential of thoracic subtraction fluoroscopy has been evaluated on the basis of our experience with this functional imaging modality in patients presenting with cystic fibrosis. The method, which consists of subtracting dynamic digital fluoroscopic images of the breathing chest in the time interval difference (TID) mode, applies to the study of the lucency variations during the respiratory cycle and provides dynamic functional information about ventilation and/or perfusion and diaphragmatic kinetics, without any injection and with minimal irradiation. To assess the validity of the TID procedure, our results were compared with standard roentgenography, clinical data, and scintigraphic findings, with emphasis on the latter. The limitations and advantages of TID compared with scintigraphy are discussed. Three groups of discrepancies emerge which do not discredit TID. TID offers rather the advantage of providing anatomic pictures and unique dynamic information, which is emphasized.
An often encountered assumption is that non-relieved renal obstruction will lead soon or late to progressive deterioration of the renal function. The effect of non-relieved partial ureteral obstruction on the separate glomerular filtration rate (SGFR) was studied throughout the whole life of a series of rats, who were submitted at the age of 3 months to partial obstruction of the left ureter. An initial and variable postoperative SGFR decrease was gradually observed, but after this period, SGFR remained stable until the natural death of the animal.
The effects of acute administration of torasemide (1-isopropyl-3-([4-(3-methyl-phenylamino)pyridine]-3-sulfonyl)urea), a new potent loop diuretic, were compared with those of furosemide in 8 healthy male volunteers (aged 22-35 years). The subjects were studied on two separate occasions, at 1-week intervals. After two baseline urine collections of 30 min, either torasemide (20 mg i.v.) or furosemide (40 mg i.v.) was given, followed by further timed urine collections after 15, 40 and 60 min. There were significant increases in urine flow, and in sodium, potassium, chloride and calcium excretion, which were maximal within 15 min after administration of both drugs. These effects were of similar magnitude except for the natriuretic and chloruretic actions which were more pronounced after furosemide than after torasemide (p less than 0.02). The drugs induced no significant changes in effective renal plasma flow or glomerular filtration rate, as measured from the clearances of constantly i.v. infused 123I-orthoiodohippuran and 51Cr-EDTA, respectively. Urinary dopamine, urinary prostaglandin E excretion and plasma renin activity were increased by both drugs. It is concluded that the acute effects of torasemide are comparable to those of furosemide.
Fifteen children underwent scintigraphy with indium 111 (111In)-labeled white blood cells (WBC) for the detection of a local suppuration. The procedure generally contributed to a correct diagnosis. False negative results were observed in 5 children, but in two of them positive foci were also present. The missed lesions were 2 liver abscesses, 1 lung abscess, foci of osteomyelitis and 1 pericarditis. Two cases of chronic granulomatous disease are presented in which increased leucocyte accumulation was not observed in proven instances of infection.
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