ABSTRACT
Relative and absolute 99Tcm-DMSA uptake measurements were carried out on 25 adult patients among whom there were 23 normal and 25 malfunctioning kidneys. Data were collected at 3 and 6 h post intravenous tracer injection. Four methods of calculating absolute uptake were investigated and evaluated. These were based on: (1) posterior view and measured kidney depth; (2) posterior view and Raynauld's depth; (3) geometric mean assuming kidney thickness is small enough not to introduce self attenuation of counts in the kidney itself; (4) geometric mean taking kidney thickness into account. Whilst (1) and (2) were found to overestimate and underestimate renal uptake by up to 5 and 14%, respectively, (3) and (4) were found to be more accurate and comparable. The measurement of relative DMSA uptake (right to left) showed no change between the 1 and 6 h measurements for both obstructed and non-obstructed kidneys. Based on the results from method 4, the absolute renal DMSA uptake had a mean value of 25.4%, S.D. 8.9% and 30.0%, S.D. 9.2% at 3 and 6 h, respectively, for normal/non obstructed kidneys. For obstructed kidneys (responding to frusemide), the mean uptake was 23.0%, S.D. 7.2 and 25.6%, S.D. 6.7% at 3 and 6 h, respectively. For obstructed kidneys not responding to frusemide, the mean uptake was 16.8%, S.D. 3.9 and 20.6%, S.D. 4.8% at 3 and 6 h, respectively. No correlation was found between absolute DMSA uptake and degree of renal obstruction.
Subject(s)
Kidney Diseases/metabolism , Kidney/metabolism , Organometallic Compounds/pharmacokinetics , Succimer/pharmacokinetics , Sulfhydryl Compounds/pharmacokinetics , Technetium , Adult , Humans , Kidney/diagnostic imaging , Kidney Diseases/diagnostic imaging , Mathematics , Methods , Radionuclide Imaging , Technetium Tc 99m Dimercaptosuccinic AcidABSTRACT
Results of studies of nasal to oral airflow ratios are reported using simple and accurate anatomical models to record the effect of differing positions of lips, tongue and soft palate, with particular reference to the effect of the position of the dorsum of the tongue and various sizes of velopharyngeal defect. The resistances to airflow produced by the labial, palatolingual, velopharyngeal and naral valves were found to be interdependent. Variations in tongue position alone could allow the same nasal airflow during a more than three-fold variation in the size of velopharyngeal defects. The degree of nasal escape of air which is responsible for the typical "cleft palate" type of speech cannot be assessed by observation of the size of the velopharyngeal defect alone.
