Analysis of renography for quantitative means in differentiating renal obstruction

Abstract

One of the causes of renal failure is due to the presence of an obstruction in the kidney. Standard evaluation of renal obstruction using renography is by visual interpretation in which diagnosis is decided based on the pattern of the graph. However, this method is highly subjective due to the intra-observer and inter-observer variability and may lead to inconclusive findings. The works in this thesis were carried out to search for objective methods in the assessment of renal obstruction through quantification of renogram and to develop robust systematic methods for clinical evaluation of renogram. First, the reference ranges of the existing parameters in the literature for both unobstructed and obstructed classes were presented which can be used to verify and justify the diagnosis of renal obstruction. Secondly, a Baseline Screening System (BSS) that can exclude obstruction and avoid unnecessary administration of furosemide based on the first 10 min result of a renogram was proposed. When the BSS does not imply the absence of obstruction, the patient needs to continue the renography with the injection of diuretics. The result of the full scanning can be analyzed by using the proposed Basic Integrative System – Renal Obstruction (BISRO). Next, new quantitative parameters, U/V2, MeanCV50 and MedianCV60, which could provide a higher accuracy of diagnosis and able to differentiate the severity of obstruction were proposed. Using these newly proposed parameters together with the existing parameters found in the literature, an Advanced Integrative System – Renal Obstruction (AISRO) was developed.