Figure 315

Renal duplex ultrasound for diagnosis of renal artery stenosis. Duplex ultrasound scanning of the renal arteries is a noninvasive screening test for the detection of renal artery stenosis. It combines direct visualization of the renal arteries (B-mode imaging) with measurement of various hemodynamic factors in the main renal arteries and within the kidney (Doppler), thus providing both an anatomic and functional assessment. Unlike other noninvasive screening tests (eg, captopril renography), duplex ultrasonography does not require patients to discontinue any antihypertensive medications before the test. The study should be performed while the patient is fasting. The white arrow indicates the aorta and the black arrow the left renal artery, which is stenotic. Doppler scans (bottom) measure the corresponding peak systolic velocities in the aorta and in the renal artery. The peak systolic velocity in the left renal artery was 400 cm/s, and the peak systolic velocity in the aorta was 75 cm/s. Therefore, the renal-aortic ratio was 5.3, consistent with a 60% to 99% left renal artery stenosis. (From Hoffman and coworkers [4]; with permission.)

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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