Asymmetrical kidneys on usg in a pt of Renovascular hypertension suggests Renal Artery stenosis and Gold standard is renal Angiography.

Perfusion Studies to Assess Differential Renal Blood Flow

Captoril-renograpy with technetium ^99m

Tc mertiatide (^99mTcMAG3)

Captopril -mediated fall in filtration pressure amplifies differences in renal perfusion Normal study excludes renovascular hypertension

Multiple limitations in patients with advanced atherosclerosis or

creatinine >2.0 mg/dL

C/I In bilateral RAS

Vascular Studies to Evaluate the Renal Arteries

Duplex

Ultrasonography

Shows the renal arteries and measures flow velocity as a means of assessing the severity of stenosis Inexpensive and good screening test

Heaviy dependent on operator's experience;

Less useful than invasive angiography for the diagnosis of fibromuscular dysplasia and

Magnetic

resonance

Angiography

Shows the renal arteries and perirenal aorta Not nephrotoxic, but concerns for gadolinium toxicity exclude use in GFR<30/mL/min/1.73 m²

Expensive;

Gadolinium excluded in renal failure,

Unable to visualize stented vessels

Computed

tomographic

Angiography

Shows the renal arteries and perirenal aorta Provides excellent image

Moderate volume of contrast required,

Potentially nephrotoxic

Intraarterial

angiograhy

Shows location and severity to vascular lesion Gold standard" for dx of large-vessel disease,

Expensive,associated hazard of atheroembolism

Contrast toxicity,

Procedure-related complications

Basics of Genitourinary Radiology