What is the role of CT angiography in the workup of renovascular hypertension (RVHT)?

Updated: Dec 01, 2020
  • Author: Rebecca J Schmidt, DO, FACP, FASN; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Answer

Spiral CT scan with intravenous contrast (CT angiography) is highy accurate in diagnosing atherosclerotic renovascular disease. [27]   Adding digital subtraction angiography (DSA) technology to renal arteriography requires one half the volume of dilute contrast medium that standard arteriography requires, while yielding comparable results.  Because intra-arterial DSA requires less radiocontrast (25-50 mL) than conventional angiography (100 mL), it is preferred for patients with compromised kidney function. RAS of 70% or more or stenosis of 50% with poststenotic dilatation is considered hemodynamically significant.

Intravenous (IV) DSA has also been suggested for identification of renovascular disease. It is less invasive than intra-arterial DSA but requires more radiocontrast. Yield depends on the skill of the individual interpreting the radiograph, and image quality is diminished by interference from patient or intestinal motion or gas (which can be reduced by abdominal pressure and glucagon), as well as by overlying vessels and poor cardiac output. Compared with arterial studies, IV DSA has a sensitivity and specificity of 90% or less and thus is not commonly used.


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