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Applying spectral Doppler to the renal artery and selected interlobular arteries, peak systolic velocities, resistive index, and acceleration curves can be estimated (Figure 4) (e.g., peak systolic velocity of the renal artery above 180 cm/s is a predictor of renal artery stenosis of more than 60%, and a resistive index, which is a calculated ...
Renal artery stenosis (RAS) is the narrowing of one or both of the renal arteries, most often caused by atherosclerosis or fibromuscular dysplasia. This narrowing of the renal artery can impede blood flow to the target kidney , resulting in renovascular hypertension – a secondary type of high blood pressure .
Radioisotopes can differentiate between passive dilatation and obstruction. It is widely used before kidney transplantation to assess the vascularity of the kidney to be transplanted and with a test dose of captopril to highlight possible renal artery stenosis in the donor's other kidney, [12] and later the performance of the transplant.
For example, the diameter was found to be 5.04 ± 0.74 mm using ultrasound but 5.68 ± 1.19 mm using angiography. [4] [5] Due to the anatomical position of the aorta, the inferior vena cava, and the kidneys, the right renal artery is normally longer than the left renal artery. [1] [6]
The procedure involves endovascular access via the femoral artery with advancement of a catheter-mounted device into the renal artery. The device uses radiofrequency or ultrasound to ablate the renal nerves. Typically, numerous ablations are applied at a different longitudinal and rotational positions to ensure maximal denervation. [13]
Abdominal ultrasound can be used to diagnose abnormalities in various internal organs, such as the kidneys, [1] liver, gallbladder, pancreas, spleen and abdominal aorta.If Doppler ultrasonography is added, the blood flow inside blood vessels can be evaluated as well (for example, to look for renal artery stenosis).
Intravascular ultrasound image of a coronary artery (left), with color-coding on the right, delineating the lumen (yellow), external elastic membrane (blue) and the atherosclerotic plaque burden (green). The percentage stenosis is defined as the area of the lumen (yellow) divided by the area of the external elastic membrane (blue) times 100.
This leads to a build-up of plaques and they can be deposited in the renal arteries causing stenosis and ischemic kidney disease. [citation needed] In this situation, the kidney supplied blood by the narrowed renal artery suffers from inadequate blood flow, which in turn causes the size of the kidneys to decrease. Other consequences include ...