신혈관성 고혈압의 선별 검사로써 조영초음파검사의 역할

Abstract

Background : Microbubbles behave like RBC in microvasculature, therefore we can measure myocardial blood flow by measuring velocity of microbubbles using ultrasound. We hypothesized that abnormal renal blood flow from renal artery stenosis can be measured using contrast-enhanced ultrasound(CEU). Methods : Renal blood flow was measured using CEU in 38 patients(18 males, 52±19 years) with suspected renal artery stenosis (unilateral stenosis 25, bilateral stenosis 3, no stenosis 10), at rest and during intravenous infusion of dopamine(2.5 μg ? kg-1?min-1). In both kidneys, refilling rate(β) of microbubbles after high-power destruction was assessed using low mechanical-index Power Pulse Inversion(HDI 5000, Philips) during continuous infusion of microbubbles. Result : Microbubble velocity(β) in the kidney with renal artery stenosis was significantly lower than the velocity in the kidney with patent renal artery(0.60±0.33 vs 0.81±0.38, p<0.05). During increased renal blood flow with dopamine, significant difference in βwas also observed between diseased and control kidney(0.81±0.28 vs 0.99±0.37, p<0.05). In patients with unilateral stenosis, more prominent differences in βbetween diseased and control kidney were observed(0.59±0.36 vs 0.84±0.43, p<0.05 at rest and 0.76±0.25 vs 1.01±0.32, p<0.005 during dopamine infusion). Using β<0.55 as a cutoff value, sensitivity was 76%, specificity was 52% for the detection of renal artery stenosis. Conclusions : Abnormal renal blood flow can be measured using CEU in patients with renal artery stenosis. CEU may be useful in screening of renal artery stenosis.