The desired vessel or cavity is punctured with a sharp hollow needle, with ultrasound guidance if necessary. A round-tipped guidewire is then advanced through the lumen of the needle, and the needle is withdrawn. A sheath or blunt cannula can now be passed over the guidewire into the cavity or vessel. Alternatively, drainage tubes are passed over the guidewire (as in chest drains or nephrostomies). After passing a sheath or tube, the guidewire is withdrawn. An introducer sheath can be used to introduce catheters or other devices to perform endoluminal (inside the hollow organ) procedures, such as angioplasty. Fluoroscopy may be used to confirm the position of the catheter and to manoeuvre it to the desired location. Injection of radiocontrast may be used to visualize organs. Interventional procedures, such as thermoablation, angioplasty, embolisation or biopsy, may be performed. Upon completion of the desired procedure, the sheath is withdrawn. In certain settings, a sealing device may be used to close the hole made by the procedure. File:Catheter Schema 1 pose de l'aiguille.Step 1 File:Catheter Schema 2 pose du fil.Step 2 File:Catheter Schema 3 retrait de l'aiguille.Step 3 File:Catheter Schema 4 entree et sortie du dilatateur.Step 4 File:Catheter Schema 5 pose du catheter.Step 5 File:Catheter Schema 6 catheter en place.Step 6 A modified technique, known as the accelerated<unk> , has also been described where the needle, guidewire, dilator, and sheath are inserted as one unit.
Seldinger technique
Converse technique
Multifocal technique
Ashby technique
Mustardé technique
Side stitch
Stenström technique
Merck stitch method