What is interventional radiology?
Interventional radiology involves the use of image guidance for the purpose of treating patients. Interventional radiological techniques can replace some open surgical procedures, allowing patients to be treated with less risk and minimising hospital stay.
Interventional radiology has been an increasingly important subspecialty of radiology since the mid-1970s, contributing to some of the most significant medical developments. Interventional radiologists invented angioplasty and the first catheter-delivered stent, first used in the legs to save patients with vascular disease from amputation or other surgical procedures. These advances pioneered the state-of-the-art treatments that are commonplace today.
What is an Interventional Radiologist?
Interventional radiologists are doctors trained in radiology and experts in reading X-rays, ultrasounds, CAT scans and other medical images.
This expertise with imaging techniques enables them to guide small catheters and guide-wires through blood vessels or other organ pathways to treat many diseases. These small catheters (tubes) are usually only a few millimetres in diameter.
In fact, interventional radiology could be termed “pinhole surgery” because of the small holes that are made in the skin to perform these procedures. Advantages to patients include less risk, less pain and shorter recovery times and general anaesthetic is usually avoided.
Interventional radiology is one of the most dynamic fields today as these physicians adapt a technique proven to work for one problem and find a way to apply it to another. For example only a few years ago, they were researching the potential way of delivering radio waves to inoperable liver tumours to see if they could be killed with heat. Today not only have they made enormous strides in treating liver tumours, they are using the same technique for kidney, breast, bone and other cancers.
When it comes to the best practices for safely performing minimally invasive medicine, interventional radiologists pioneered the procedures and the standards for safety and quality. First these procedures are performed by specialists with an in-depth foundation in diagnostic radiology.
In addition, patient safety was incorporated into the development of these advances because Interventional Radiology and diagnostic radiology training programmes include radiation safety, radiation physics, the biological effects of radiation and injury prevention.
The history of Interventional Radiology
The history of Interventional Radiology is a fascinating look at innovative pioneers who changed the delivery of medicine and greatly improved the quality of patients' lives.
The improved ability of radiologists to see inside the body gave rise to Interventional Radiology (IR) -- minimally invasive targeted treatments performed under guided imaging -- in the mid-1970s. Interventional Radiology procedures are a major advance in medicine, since they do not require large incisions, and offer less risk, less pain and shorter recovery times compared to surgery. Interventional radiologists invented angioplasty and the first catheter-delivered stent, state of the art treatments that are common place in medicine today.
Advantages of Interventional Radiology
Only a short hospital stay is required for most procedures.
General anaesthesia is usually not required.
Risk, pain and recovery time are usually reduced compared to conventional surgery.
Interventional Radiologists - The best kept secret in medicine
Modern, minimally invasive treatments are available for many diseases, but few patients know to ask about them, or to seek out a second opinion from an interventional radiologist.
Historically, interventional radiologists have been the specialists’ specialist and patients did not have direct contact with them.
Because surgery was the only treatment available for many years, many primary care physicians still refer their patients to surgeons and rely on the surgeon to provide the consult on available treatment options. However, surgeons are generally poor gatekeepers for knowing the minimally invasive treatments that another specialty offers. Eventually this paradigm will be changed and patients will be sent to the least invasive practitioner for consult first, but in the meantime, it is important for patients to know their options.
Imaging guided procedures:
Angiography: real-time X-ray images of arteries or veins following injections of contrasts (a liquid that shows up on the images during the test) delivered through a thin catheter into a blood vessel. This shows the inside of the blood vessel and is used to locate blockages and other blood vessel problems. This is the primary method used to guide many procedures that interventional radiologists perform in the circulatory system, such as angioplasty, stent placement, embolisation (blocking of blood vessel), thrombolic therapy (dissolution of blood clots) and targeted delivery of chemotherapy.
Computed tomography (CT) Angiography: ACT scan is an X-ray imaging test that provides detailed crossed sections of the body’s internal tissues. Contrast is given intravenously during the study to make arteries and veins very prominent. The series of cross sections obtained during CT scanning can be used to create a 3 dimensional picture of the blood vessels called a CT Angiogram (CTA), plus it can often replace the need for traditional angiography to determine if a patient may benefit from Angioplasty or stent placement for artery and vein occlusions.
Magnetic Resonance Angiography (MRA): MRA uses radio waves, delivered while the patient is placed in a magnetic field, to create images of arteries and veins. MRA is a particularly powerful vascular imaging modality in that it is extremely safe, non-invasive, does not require radiation and can be used safely in patients who have impaired kidney functions. However, it is rarely used in ‘real-time’ to guide therapy.
Ultrasound: To obtain an ultrasound image, inaudible sound waves are emitted from a probe and reflected back to the probe by the internal organs. The reflected sound waves are used to build a 2-Dimensional image similar to the use of SONAR by submarines. Ultrasound lets the physician see inside the body without using radiation, and is commonly used as the first method to evaluate for vascular blockages and aneurysm. It also provides a robust guidance tool for many interventional radiology procedures such as biopsies, abscess drainage and tumour ablation.
CIRSE thanks the Society of Interventional Radiology (SIR) for their kind corporation and permission regarding the use of their scientific material, edited by CIRSE specialists.