Resistive intrarenal index: myth or reality?

Abstract

In renal diagnosis, the B-mode ultrasound is used to provide an accurate study of the renal morphology, whereas the colour and power Doppler are of strategic importance in providing qualitative and quantitative information about the renal vasculature, which can also be obtained through the assessment of the resistive index (RI). To date, this is one of the most sensitive parameters in the study of kidney diseases and allows us to quantify the changes in renal plasma flow. If a proper Doppler ultrasound examination is carried out and a critical analysis of the values obtained is performed, the RI measurement at the interlobar artery level has been suggested in the differential diagnosis between nephropathies. The aim of this review is to highlight the pathological conditions in which the study of intrarenal RI provides useful information about the pathophysiology of renal diseases in both the native and the transplanted kidneys.

Developing new evaluation methods in systemic lupus erythematosus

“…The Resistive Index (RI) is an ultrasonographic parameter, easy to perform, integrating data about the arterial compliance, pulsatility and peripheral resistance. The increase of RI has been described in several kidney diseases, such as hemolytic uremic syndrome, renal vein thrombosis and allograft rejection [23].…”

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“…O IR encontra-se O IR é considerado dentro da normalidade em adultos quando inferior a 0,7, sendo a média de normalidade em torno de 0,6 (em crianças pequenas o IR pode se apresentar acima de 0,7). 182,183 No caso da EAR, um IR < 0,8 relacionou-se, em alguns estudos, com melhor prognóstico após a revascularização renal, quando comparado com IR ≥ 0,8, no que diz respeito à melhora da hipertensão arterial e da função renal. 180,181 O valor IR >0,8 antes da revascularização renal foi associado a maior mortalidade por todas as causas em pacientes hipertensos.…”

Renal arterial resistive index in Egyptian patients with lupus nephritis: Correlation with disease activity and biopsy parameters

“…Few studies have been carried out on patients affected by systemic vasculitis to evaluate the association between the anatomo-pathological findings and Doppler ultrasound parameters (Platt et al, 1990;Granata et al, 2014). Interestingly, the morphological changes of the Doppler waves found in these patients are similar to those of patients affected by renal microangiopathy related to haemolytic-uraemic syndrome (Patriquin et al, 1989).…”