Evaluation of change in blood flow by contrast-enhanced power Doppler imaging during norepinephrine-induced renal vasoconstriction.

Abstract

We evaluated the changes in flow induced by intrarenal infusion of norepinephrine by an ultrasonographic contrast agent and power Doppler imaging. Hypoperfusion was induced in dogs (N = 5) by infusing norepinephrine directly into the renal artery for 30 min at doses of 0.7 microg/kg/min, 1.0 microg/kg/min, and 1.9 microg/kg/min. Contrast agent injections were made before and after each infusion of norepinephrine. The transit of contrast agent through the kidney and color enhancement were measured by computer analysis of power Doppler images. Mean transit time and effective renal plasma flow were measured. The effective renal plasma flow decreased by 29%, 30%, and 64%, respectively, with the increasing doses of norepinephrine. Paralleling this change, the mean transit time, which corresponds to reduction in renal blood flow, increased by 26%, 43%, and 77%, respectively, from the preinfusion value. Regression analysis shows renal blood flow to decrease exponentially with norepinephrine dose. Renal blood flow changes measured by contrast-enhanced imaging correlated closely with the effective renal plasma flow measurements. Computer analysis of contrast-enhanced power Doppler images allowed measurement of renal blood flow. This technique may be useful in assessing renal perfusion during pharmacologic and other therapeutic interventional procedures.

A novel ultrasound method for evaluation of collateral development in limb ischemia

“…Furthermore, similar software used in this study has also been employed to measure blood ow in tumors, both human 5 and animal, 7 and in calculating renal blood ow, again demonstrating clinical utility. 6 The blood ow results on ultrasound from the present study paralleled the changes seen on perfusion as measured with microspheres. Therefore, the described color and power Doppler imaging technique holds promise for studying the response of patients to therapeutic angiogenic growth factors.…”

Assessment of pharmacologically induced changes in canine kidney function by multiparametric magnetic resonance imaging and contrast enhanced ultrasound

“…Several human studies showed that CEUS can identify changes in renal perfusion caused by pharmaceuticals ( 78 , 79 ). In dogs, contrast-enhanced power Doppler imaging detected significant changes in perfusion parameters induced by norepinephrine ( 80 ). It must be highlighted, however, that the magnitude of the significant changes induced was substantial, ranging from 47 to 92% in these human studies ( 78 , 79 ) and 62 to 94% in the canine study ( 80 ).…”

Contrast-enhanced ultrasound: A promising method for renal microvascular perfusion evaluation

“…CEUS has also been successfully used for monitoring renal microvascular perfusion in ischemia/reperfusion injury in mice [26] , chronic renal ischemic injury in animal models [27] , porcine intra-abdominal hypertension [28] , as well as global hypoxia in piglets [29] . Examination of norepinephrinetreated dogs showed that CEUS parameters were predictive of effective renal plasma flow, suggesting that CEUS could also be used in assessing renal perfusion following pharmacologic intervention [30] .…”