Re: The effects of renal pelvic pressure elevation on isotope nephrography and renal transit time, an experimental study.
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Animals↗
Biomedical subjects
A Piepsz
Publications and source records attributed to A Piepsz.
99Tcm-DMSA uptake in obstructed kidneys. How inaccurate are the 5 h measurements?
Partial obstruction of the left ureter was created in 19 rats and a relative 99Tcm-DMSA uptake was obtained 5 and 24 h after intravenous injection of the tracer. A systematic and variable overestimation of the left to right uptake ratio was found at 5 h, with a mean error of 15.8% (S.D. = 12.2).
Animals↗
Gastric emptying with gastro-oesophageal reflux.
The time taken for gastric emptying of a liquid (milk) or a semi-liquid (pudding) meal was evaluated in 477 infants and children. These patients were referred for suspected gastro-oesophageal reflux and underwent gastro-oesophageal scintigraphy, prolonged oesophageal pH study, manometric evaluation of the lower oesophageal sphincter pressure, and fibreoptic endoscopy. No difference in gastric emptying was observed in children aged under 3 years, regardless of the presence or absence of the gastro-oesophageal reflux, the pressure of the lower oesophageal sphincter, or the presence of oesophagitis. In children over 6 years, however, gastric emptying was significantly delayed in those presenting with reflux compared with those without reflux; in children over 3 years there was slower gastric emptying in those with a decreased lower oesophageal sphincter pressure compared with those with higher pressure and in those with overt oesophagitis compared with those without oesophagitis. This study suggests that gastro-oesophageal reflux is more severe in childhood than in infancy, probably due to more complex motor disorders affecting the gastric fundus as well as lower oesophageal sphincter function.
Adolescent↗
Reproducibility of three methods of renal clearance estimation without blood samples by means of 99mTc-DTPA.
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Animals↗
Effect of carvedilol on ambulatory blood pressure, renal hemodynamics, and cardiac function in essential hypertension.
A randomized, double-blind, placebo-controlled study was set up to study the effects of acute and chronic administration of carvedilol, a vasodilatory beta-blocker in essential hypertension. Acute administration of a single dose of 50 mg of carvedilol reduced systolic and diastolic blood pressure, without inducing reflex tachycardia. Renal blood flow was preserved; accordingly renal vascular resistance was significantly reduced. A significant reduction of glomerular filtration rate and filtration fraction was observed. Plasma renin activity (PRA) and plasma aldosterone were not changed. Chronic carvedilol treatment produced a significant fall in systolic and diastolic office and ambulatory blood pressure, heart rate, cardiac output, PRA and plasma aldosterone. Blood pressure variability was not changed. Renal blood flow, glomerular filtration rate and filtration fraction also remained unchanged; renal vascular resistance decreased significantly. It is concluded that carvedilol possesses definite antihypertensive and renal vasodilating properties, both acutely and after chronic treatment.
Adrenergic beta-Antagonists↗
Radioisotopic evaluation of the renal parenchymal function in children with ureteropelvic junction obstruction. A retrospective study.
Separate glomerular filtration rates were evaluated in 21 children with uni- or bilateral ureteropelvic junction stenosis, using the Tc-99m DTPA complex and the scintillation camera. The grade of alteration seen on urograms has influenced the surgeon in his decision to use a conservative or a surgical treatment, whereas the type of intervention (pyeloplasty or nephrectomy) was mainly based on the scintigraphic quantitation. The morphological data provided by an excretory urogram could not predict the degree of functional impairment. The scintigraphic evaluation of single kidney clearance was useful in the evaluation of the effects of medical and surgical treatment.
Adolescent↗
Technetium-99m DMSA imaging and the obstructed kidney.
Although several authors have claimed that the function of an obstructed kidney could be overestimated on Tc-99m DMSA imaging, the clinical importance of such an overestimation has not been well documented. Partial obstruction of one ureter was created in a rat, and a relative Tc-99m DMSA uptake was obtained 4 hours after intravenous injection. By puncture of the isolated obstructed kidney, it was shown that the function of that kidney was overestimated by at least 17%.
Animals↗
Oesophageal transit patterns in healthy subjects.
Oesophageal transit was studied in 49 healthy volunteers. When a good quality bolus was reached, the tracer passed through the oesophagus leaving no residual activity. The mean time of transit of the total oesophagus was 4.5 +/- 1.3 s. In cases of fragmented bolus, residual activity was found in about 80% of the cases giving rise to a prolonged transit time. When using 81Krm, artefacts due to fragmented bolus can easily be overcome by repeating the test as often as necessary.
Adult↗
Evaluation of the accuracy of steady-state krypton-81m method for calculating right ventricular ejection fraction.
The accuracy of a steady-state 81mKr method for calculating the right ventricular ejection fraction (RVEF) has been examined in this study. Causes of errors using this method and their effects on the calculated RVEF were evaluated. The results suggested that mixing in the right ventricle during continuous infusion of 81mKr was homogenous, allowing for the calculation of ejection fraction using the count rate ratio. Lung activity was quite important and could not be neglected in computing RVEF, but the use of [99mTc]MAA lung perfusion scanning seemed to allow a correct subtraction of this background activity. The delineation of right ventricular regions of interest (ROIs) was complicated by the translation movements of the right ventricle during heart contraction. These ROIs should be drawn carefully on the count density distribution images and data shown by parametric images; such as first and second harmonic phase, amplitude images, and composite stroke volume image should be considered. Furthermore, this study demonstrates the superiority of the 81mKr technique compared with 99mTc methods for computing RVEF. In conclusion, even if the true accuracy of the 81mKr method for calculating RVEF cannot be proven due to the lack of reference methods, strong, suggestive evidence that the technique should be accurate is shown here.
Adult↗
Evaluation of esophageal transit in children and in infants by means of Krypton-81m.
This paper presents the results of Krypton-81m esophageal transit study in a series of children and infants presenting various esophageal disorders. The advantage of Kr-81m, compared to other radionuclides, is that the radiation dose to the patient is extremely low. The study can therefore be repeated as often as necessary and a high dose can be given to ensure good quality results. The method is very easy to perform and allows a quantitative assessment of esophageal transit in physiological conditions. The method gives information about the severity of altered transit and it is particularly useful in studying the effects of treatment.
Adolescent↗
Pubic osteomyelitis.
A case of pubic osteomyelitis in a child is presented. A well localized hyperactive area on a Tc-99m MDP bone scan provided the correct diagnosis. This scintigraphic localization of osteomyelitis seldom has been reported.
Child↗
A simple data display for qualitative assessment of esophageal transit.
A simple data processing technique for qualitative assessment of esophageal transit is presented and its clinical value is demonstrated.
Data Display↗
Oesophageal transit of liquid: effects of single or multiple swallows.
The effects of single and multiple swallowing on oesophageal transit have been evaluated in healthy subjects. It was shown that the transit patterns observed after multiple swallowing were different from that observed after a single swallow. It was concluded that for the detection of oesophageal transit abnormalities, the test should be performed using a single swallowed bolus.
Deglutition↗
Influence of statistical noise on the determination of the single kidney 99Tcm-DTPA clearance.
Single kidney clearance can be obtained using the 99Tcm-DTPA complex and the scintillation camera. In order to evaluate the influence of statistical noise on the determination of the clearance, several non-noisy curves were constructed, simulating renal, background and precordial curves. Poisson noise was added to these curves and the clearance results were compared to those obtained on the original curves. It was shown that, in so far as a moderate curve smoothing was used, the statistical noise did not interfere considerably with the results of the renal clearance.
Glomerular Filtration Rate↗
Computer analysis of radionuclide esophageal transit studies.
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Esophagus↗
Quantitation of esophageal transit by means of 81mKr.
A method for quantifying esophageal transit by means of 81mKr is described. The principal advantage of 81mKr compared with 99mTc is its ultra-short half-life with its consequences on radiation dose and counting statistics. Factors which may influence the esophageal transit time such as body posture, volume of the tracer, and the nature of the tracer were studied. The reproducibility of the technique is quite good and its capacity to detect minor esophageal transit disorders is demonstrated.
Adult↗
Unusual cholescintigraphic findings in polyarteritis nodosa.
Bile duct cysts as a consequence of liver infarcts have exceptionally been described in polyarteritis nodosa. A case is reported in which necrotic changes due to arterial occlusion, as well as the resulting hepatic bile duct cysts, were clearly demonstrated by diethyl IDA cholescintigraphy.
Adult↗
The evaluation of right ventricular performance using krypton-81m.
The availability of krypton-81m suitable for intravenous injection provides an easy means for assessing right ventricular function. The superimposition of the other heart chambers does not constitute a problem. The activity in the left heart is negligible and the study can be performed in the right anterior oblique position to obtain optimal separation between the right atrium and the right ventricle. Lung activity is quite high and should be corrected before computing the right ventricular ejection fraction. This correction can be accomplished by performing Tc-99m MAA perfusion scintigraphy. The measurement of the right ventricular ejection fraction appears to be reproducible with very small inter-and intraobserver variability. Good quality phase and amplitude images can be obtained with such high count rates.
Cardiac Output↗