Many interventional procedures have the primary aim of managing narrowings or blockages to restore flow of blood, urine, bile, air or even bowel contents. Once access into the appropriate lumen has been achieved, the basic principles of catheters and wires are used to navigate through the diseased segment. This chapter is concerned with the mechanics of getting across to the other side. Success is largely governed…

Knowing the equipment is a great start but it comes into its own if you know how to use it. Remember wires go first, and the initial step of most procedures is to establish safe guidewire access to the target zone. Alarm Exceptions to the catheter follows the wire are: manoeuvring a pigtail up and down the aorta and moving catheters up and down the aorta…

Angiography is a team sport and a successful angiogram depends on cooperation between the patient and the angiography staff (radiographer, nurse and doctor). A little understanding of the basic principles of angiography can vastly improve the standard of the final study. This chapter reviews the key areas in image acquisition and manipulation. Digital subtraction angiography: basic principles Digital subtraction angiography (DSA) uses a computer to subtract…

Vascular access is the starting point for all diagnostic and interventional arterial and venous procedures. Common principles apply regarding choice of access site and equipment but there are significant differences between puncturing arteries and veins. Choice of puncture site is dictated by the planned procedure; think what you need to achieve, consider the site of the lesion, and the size of sheath and catheter required. The…

Many interventional radiology procedures remain dependent on X-ray guidance. It is important to have good technique in order to minimize the radiation dose to the patient, yourself and the staff. Fluoroscopy Fluoroscopy or screening Real-time imaging is essential for catheter and guidewire manipulation. Whenever using fluoroscopy consider how to balance image quality with radiation dose. There are several factors which will come into play and different…

A wide range of interventional procedures can only be safely performed with accurate imaging guidance. The aim of this chapter is to outline the basic principles of imaging-directed intervention. Ultrasound, computed tomography and fluoroscopy have complementary roles; individual circumstances dictate the optimal modality. Ultrasound guidance Ultrasound is ideal for many biopsy and drainage procedures and allows the procedure to be visualized in real-time. Use ultrasound if…

Purpose Ureteric stents are placed across ureteric strictures to relieve ureteric obstruction and restore anatomical drainage from the renal pelvis to the bladder/ileal conduit. Description All ureteric stent systems are hollow plastic tubes with a double-ended pigtail configuration ( Fig. 25.1 ). There are differences in materials and delivery systems. Interventional radiologists are usually involved in antegrade stent placement via a nephrostomy. A pusher is used…

Purpose Drainage catheters allow fluid to be released from collections and structures. You’re Reading a Preview Become a Clinical Tree membership for Full access and enjoy Unlimited articles Become membership If you are a member. Log in here

Essential equipment Embolotherapy is the deliberate blockage of blood vessels; embolization may be lifesaving when used to stop haemorrhage. Embolization is increasingly used as an adjunct to surgery and in the treatment of a variety of benign and malignant tumours. Many embolic agents are available to block vessels of different sizes, from large arteries to capillaries. The choice of the agent used depends on the individual…

Purpose Inferior vena cava (IVC) filters are placed to prevent pulmonary embolism. They are most often used when there is a contraindication to anticoagulation. Despite the name, they are occasionally used in the superior vena cava. Description IVC filters use a form of wire lattice, often umbrella-shaped, to catch large blood clots, while allowing flow through the inferior vena cava. They are introduced in a constrained…

Purpose Covered stents provide an impermeable conduit and are used in both the vascular and non-vascular system. In the vascular system, they are called ‘stent grafts’. Vascular The most important indications are treating aneurysms and arterial rupture. Other indications are TIPS and in certain circumstances to manage stenotic and occlusive disease. Non-vascular Outside the vascular world, they tend to be called ‘covered stents’. In the majority…

Purpose Stents are scaffolds used to maintain luminal patency in many systems, e.g. vascular, biliary, gastrointestinal and tracheobronchial. They act by exerting an outward radial force to overcome stenoses/occlusions and elastic recoil after angioplasty. Stents may also reduce the likelihood of distal embolization during angioplasty by trapping plaque/thrombus against the vessel wall. Description Stents comprise a metal strut latticework, they have a high expansion ratio allowing…

Purpose The only way to be certain a balloon is being used at the correct pressure is to use an inflation handle with a pressure gauge ( Fig. 19.1 ). Besides precision, the inflation handle allows you to effortlessly generate and sustain high pressures without hurting your skilled hand. Description These are modified syringes, the plunger is driven into the syringe barrel with a screw thread…

Purpose of equipment These are mostly used to dilate blood vessels but can be equally useful for strictures in other systems. Description Although there is a huge variety of different angioplasty balloons, they all boil down to a straight catheter with an inflatable balloon at the distal end. All angioplasty balloons have a channel for a guidewire and a separate channel to allow balloon inflation There…

Purpose Snares are essentially wire loops, which are used to capture/manipulate/remove wires, catheters and various other ‘foreign bodies’. Description All snares are variations on the good old cowboy lasso, in other words, they have a loop that can be rotated and manoeuvred onto a target and then tightened by advancing a catheter to close the loop. Simple single-loop lasso design The nitinol Amplatz GooseNeck snare is…

Purpose Even the strongest angiographer cannot hand inject rapidly enough for aortic runs. Pump injectors are used to deliver a rapid controlled bolus of contrast while you stand back and reduce your radiation dose. You’re Reading a Preview Become a Clinical Tree membership for Full access and enjoy Unlimited articles Become membership If you are a member. Log in here

Taps Purpose Just as with domestic taps, these are turned on and off to control flow and there is even a mixer version. Description Only two types of tap are of importance but there are some important caveats: Two-way taps These taps have two positions – on and off – they are often used on the end of connecting tubes. Two-way taps come in two styles:…

Sheaths and guide-catheters are designed to allow the coaxial passage of other devices. There is overlap between the structure and function and recently, introducer guides have developed as a crossover group. There are differences in sizing and usage, so the devices will be discussed separately. Sheaths Purpose Sheaths act as atraumatic access conduits for other equipment. There are two main designs: the vascular access sheath and…

Purpose Microcatheters allow catheterization and delivery of embolic material to the smallest and most tortuous of vessels ( Fig. 13.1 ). Microcatheters are ideal for super-selective hepatic, visceral and peripheral catheterization. You’re Reading a Preview Become a Clinical Tree membership for Full access and enjoy Unlimited articles Become membership If you are a member. Log in here

Purpose Non-selective catheters with multiple sideholes are used for rapid injection of contrast into large–medium-sized arteries. Selective catheters may have sideholes or just a single endhole; they are shaped to allow the catheter to enter branch vessels or direct guidewires into them. Description Catheters come in a wide range of shapes, sizes and constructions. Simple rules govern catheter choice. Most interventional radiologists rely on a relatively…