The Ideal Radiology Lab
With “one-room-fits-all” procedures, equipment quality means a lot.
The interventional radiologist performs a wide array of peripheral vascular procedures including angioplasty, stenting, and revascularization of vessels, using balloons as well as other new devices. These procedures are performed throughout the body, including in the renal, carotid, iliac, femoral, and tibial arteries. Interventional radiologists are also involved in endovascular repair of aneurysms including thoracic, abdominal, and iliac aneurysms, as well as pseudoaneurysms.
Embolization is an important part of the interventional practice. These procedures include chemoembolization, tumor ablation, fibroid embolization, vascular malformation embolization, and embolization of bleeding vessels in the gastrointestinal tract and trauma embolization. Procedures creating vascular shunts, such as a transjugular intrahepatic portosystemic shunts (TIPS), are complex tasks performed by interventionalists that require sophisticated imaging and technology. Interventionalists perform nonvascular interventions in the biliary tree, the urinary system, and the gastrointestinal system percutaneously using the same imaging equipment required for vascular procedures.
“GOOD” OFTEN EQUALS NEW
At the Miami Cardiac and Vascular Institute, interventional radiologists work in a dedicated area of the hospital with sophisticated imaging equipment in each of the laboratories. There is some variation in equipment from room to room and cases may be placed in a particular room based on the type of procedure. In many hospitals there is one ?good? room and one ?bad? room, which basically translates into a room with new equipment and a room with old (or older) equipment. The difference between the two can be great enough to affect procedure scheduling and the ability to perform a case properly.
VERSATILE IMAGING IS CRUCIAL
An interventional radiologist’s imaging needs are different from those of other interventional specialists. To achieve positive outcomes in the wide variety of cases, very sophisticated imaging equipment is required. C-arms and image intensifiers that are standard in ORs usually are not adequate for the wide scope of work performed. Imaging units that are very versatile and that have a field of view at least 15 inches in size are required. Many companies make monitors of this size, but they are not yet the standard in most cath labs.
Radiologists perform imaging over all parts of the body—we look at areas as diverse as the hand and the abdomen. The hand is thin with no fat layer, and x-rays will penetrate quite easily. The abdomen presents another set of problems because of body weight and density. A versatile machine will be able to acquire a quality image, regardless of the body part in question.
Digital Subtraction Angiography
We don’t use cine; all of our imaging is digitally acquired. Digital subtraction angiography (DSA) is standard in all high-quality interventional laboratories. There are many digital system features that facilitate interventional procedures. One of these is called “road mapping,” which allows an image to be stored and then recalled (using fluoroscopy) so that all new images are superimposed over the old image. This is extremely useful in vascular interventions.
Various interventional DSA units are available. We tend to use Philips (The Netherlands) equipment and are currently using the state-of-the-art Integris Allure system, which is utilized for most of our interventional procedures. Siemens (Malvern, PA), GE (Waukesha, WI), and Toshiba (Tustin, CA) also have sophisticated imaging units available; the model you choose depends on your personal needs and preferences.
In addition to a large field of view, look for a DSA machine that offers collumnated radiation for a narrow focus and a good filtering system that will prevent a lot of scatter. A quality machine should allow the physician to alter filming rates from three or six images per second to one image every other second. The system should be user friendly and easy to adjust to meet the needs of the interventionalist.
IMAGE PROCESSING AND REVIEWING
It is important to have the ability to process and review images quickly. When choosing equipment, consider the ability to manipulate images to add or subtract bones, magnify, add or subtract contrast or brightness to darken or lighten the background, or add images together at the early, middle, or late phases. You should be able to perform these manipulations at any time, including midprocedure. The ability to calibrate and measure vessels is also important; for example, while performing an AAA procedure it is very helpful to be able to measure the diameter of the vessel.
Such capabilities are all in the software, and the selection of functions you can choose from depends on the manufacturer. The images are stored digitally, but can be printed on films. Many radiology departments are becoming filmless environments, but most people still print images out on standard x-ray films so they have something familiar to read. This will soon become outdated as digital images can be stored and retrieved as necessary, negating the need for costly and bulky film.
It is important to have the ability to integrate more than one type of imaging modality. For example, we often use ultrasound when gaining access to vessels—it is very helpful when we puncture, especially in the venous system. We also use ultrasound during biopsies. The ability to use different modalities for imaging broadens the scope of procedures that can be performed.
To utilize ultrasound during procedures, however, we need to have more than one screen in the room. At our facility we have up to four screens that we can use for various functions; we can view images, monitor waveforms for blood flow in the vessel, and display static images as a reference all at the same time.
MONEY CAN MATTER
In a discussion of the ideal equipment, it is important to understand that the imaging tools are very expensive. Costs include not just the equipment, but the actual room construction as well. Interventional laboratories require specific radiation shielding. The imaging equipment alone can cost in excess of $1 million and therefore many interventional radiology departments have only one state-of-the-art lab. In our practice, we are fortunate enough to have several state-of-the-art laboratories.
A well-trained interventional radiologist can often work around equipment deficiencies. Remember, despite technological changes that can quickly make equipment seem obsolete, these tools are built to last a long time and upgrades to existing equipment are available.
James Benenati, MD, is the Medical Director of the Noninvasive Vascular Laboratory and Interventional Radiologist at Miami Cardiac and Vascular Institute in Miami. Dr. Benenati may be reached at (305) 598-5990; firstname.lastname@example.org.