Kidney sonography, also known as renal ultrasound, is a non-invasive imaging technique used to produce images of the kidneys using high-frequency sound waves. The images produced can help diagnose and monitor conditions affecting the kidneys, such as kidney stones, cysts, tumors, and other abnormalities.

During a kidney sonography, a transducer (a device that emits and receives sound waves) is placed on the skin over the kidney area. Sound waves are emitted from the transducer and pass through the body, reflecting off the structures within the kidneys. These reflected sound waves are detected by the transducer and converted into images that can be viewed on a screen.

Doppler ultrasound is a type of kidney sonography that uses sound waves to measure the speed and direction of blood flow in the renal blood vessels. This information can help diagnose conditions such as renal artery stenosis (narrowing of the renal artery) and renal vein thrombosis (a blood clot in the renal vein).

Doppler ultrasound works by emitting sound waves at a specific frequency that is reflected off the red blood cells in the blood vessels. The frequency shift in the reflected sound waves indicates the speed and direction of blood flow.

Kidney sonography and Doppler ultrasound are safe and non-invasive procedures that do not involve radiation exposure. They are typically performed by a trained technician or radiologist and do not require any special preparation by the patient.