n. wire used as a guide to insert a catheter during interventional procedures, particularly in the *Seldinger technique. Guidewires often have multiple cores and a variety of coverings, depending on their functions, and they vary in stiffness and thickness. Their ends may be curved, to get past tight strictures, or J-shaped, to avoid accidentally puncturing a vessel wall or other structure while being pushed forward.
n. examination of the bladder by means of an instrument (cystoscope) inserted via the urethra. The cystoscope consists of either a metal sheath surrounding a telescope and light-conducting bundles or a flexible tube with built-in optical fibres for viewing and illumination. Irrigating fluid is conducted through a channel into the bladder. When using the rigid instrument, additional channels are available for the insertion of guidewires, ureteric catheters, diathermy electrodes, or biopsy forceps for taking specimens of tumours or other growths. When using the flexible cystoscope, only small instruments can be passed through the additional channel, such as biopsy forceps, diathermy electrodes, or laser fibres for the destruction of tumours or stones.... cystoscopy
(IVUS) a technique in which a micro *ultrasound transducer is mounted on a catheter, which is then advanced over a guidewire into a blood vessel. IVUS is used to accurately assess the diameter of the blood vessels before any treatment, to assess any internal abnormality within the blood vessels, or to help mark the blood vessel branches during any stent placement.... intravascular ultrasound
n. an instrument (*endoscope) used for examining the interior of the kidney, usually passed into the renal pelvis through a track from the skin surface after needle *nephrostomy and dilatation of the tract over a guidewire. The nephroscope allows the passage of instruments under direct vision to remove calculi (see percutaneous nephrolithotomy), or to disintegrate them using ultrasound probes or pneumatic energy via a lithoclast, or a combination of the two.... nephroscope
a method for introducing a catheter into a blood vessel or cavity. First, a needle is used to puncture the structure, then a *guidewire is passed through the needle. The needle is removed, and the catheter is introduced over the wire. The technique is used in angiography, cardiac catheterization, cannulation of large veins, and drainage of abscesses and other body cavities. [S. I. Seldinger (1921–98), Swedish radiologist]... seldinger technique
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