A New Method for Evaluation of Split Renal Cortical Blood Flow with Contrast Echography

Abstract

The recent development of contrast echography has made renal enhancement possible through an intravenous injection of microbubble-based contrast. In animal models, tissue perfusion can be quantified using contrast echography by measurement of the rate at which microbubbles replenish tissue after their ultrasound-induced destruction. Our purpose in this study was to evaluate renal blood flow with contrast echography in humans. To increase the sensitivity for microbubbles, we used a combination of power Doppler harmonic and intermittent imaging. The pulsing interval (PI) was changed from 10 cardiac cycles to 1 cardiac cycle during an intravenous infusion of the contrast agent, and alterations in the intensity of the renal cortex were represented as a decline ratio (DR). In 24 patients with various renal diseases, we were able to observe all 48 kidneys with adequate enhancement of the renal cortex. At PI of 10 cardiac cycles, the enhancement was homogeneous and strong, while, obviously, changing PI from 10 to 1 cardiac cycles caused a decline of enhancement. An excellent correlation was found between DR using contrast echography and

Evaluation of Renal Microcirculation by Contrast-Enhanced Ultrasound With SonazoidTM as a Contrast Agent Comparison Between Normal Subjects and Patients With Chronic Kidney Disease

“…They also found that this attenuation exhibited a significant positive correlation with renal plasma flow. 13) Although their period of observation of cortical enhancement was only 7 seconds, the delay in rising demonstrated by a decrease in S-P slope and reduction of peak echogenicity with progression of CKD stage observed in the early phase of our present study with 600-second observation are consistent with their findings. It seems likely that the increase in renal resistance due to the decrease in number of glomeruli and peritubular capillaries as well as narrowing of arterioles contributes to the delay in rising and reduction of peak intensity with progression of CKD stage we observed.…”

“…Almost all previous studies of renal vasculature with CEUS used first-generation contrast agents, which elicit signals by the collapse of micro-bubbles, and the observation period was too short for clear examination of the renal microvasculature. 5,13) In contrast, the second-generation enhancer Sonazoid TM has a stable phospholipid shell in each micro-bubble, and since the enhancement signals obtained with it are elicited by resonance rather than bursting of micro-bubbles, stable long-term contrast enhancement can be obtained. Although Sonazoid TM is known to be captured by the reticulo-endothelial system, after intravenous injection almost all of it remains entirely within the intravascular space without being trapped in normal small vessels.…”

Real-time measurement of renal blood flow in healthy subjects using contrast-enhanced ultrasound

“…Hosotani et al (5) compared RBF obtained by CEU, radionuclide scanning using 99m technetium-mercaptoacetyltriglycine ( 99m Tc-MAG3), and PAH in 16 patients with chronic kidney disease of various causes. The authors demonstrated a significant correlation (r ϭ 0.69, P ϭ 0.005) between CEU and RBF determined by PAH clearance.…”

Renal frame count: A quantitative angiographic assessment of renal perfusion

“…Renal perfusion has traditionally been measured using nuclear scintigraphy [3][4][5], although recently computerized tomography (CT) [6,7], positron emission tomography (PET) [8], magnetic resonance imaging (MRI) [9], and contrast-enhanced Doppler ultrasonography have been used to assess renal blood flow [10]. Although renal angiography remains the gold standard for the diagnosis of renal artery stenosis, there is no angiographic method to assess kidney perfusion objectively.…”