What is interventional radiology?
Interventional radiology (IR) is a sub-specialty of radiology that has become increasingly important since the mid-1970s, contributing to some of the most significant medical developments in recent years. Using imaging techniques such as X-ray, CT, MRI and ultrasound for guidance, patients can be diagnosed and treated using minimally invasive procedures.
Nowadays, the techniques used in interventional radiology offer new treatment options for many conditions, allowing patients to be treated with less risk and shorter hospital stays. IR procedures can be used in almost every organ system, and the list of conditions that can be diagnosed and treated using image-guided techniques is continuously growing. Body parts and systems that can be treated using IR include:
- Abdomen (intestine, kidneys, liver, stomach)
- Central nervous system (brain, spine)
- Chest (lungs, respiratory system)
- Heart and vascular (arteries, veins, haemodialysis access)
- Musculoskeletal (bones, joints, spine)
- Genitourinary (uterus, testes, kidneys)
- Other organs and soft tissues.
Interventional radiologists can provide patient evaluation and management, meaning that they evaluate the patient beforehand and give the patient information on the procedure. They can also be involved in post-procedural care, both in cases where they work alone and in cases which involve collaboration with other physicians.
What is an interventional radiologist?
Interventional radiologists are doctors trained in radiology and in minimally invasive procedures. They are experts in reading X-rays, ultrasounds, CT and other medical imaging techniques.
This expertise with imaging techniques enables them to guide small catheters (tubes) and guidewires through blood vessels or other organ pathways to treat many diseases. These small catheters are usually only a few millimetres in diameter.
Interventional radiologists have historically been the specialists’ specialist and patients did not have direct contact with them. Now, however, patients can be directly referred to an interventional radiologist; if you would like further information on direct referrals, please speak to your doctor.
For many years, surgery was the only available treatment option for a number of conditions. As a result, many primary care physicians still refer their patients to surgeons and rely on the surgeons to provide information on the range of possible treatment options.
However, surgeons tend not to be fully informed about the different minimally invasive treatments on offer, and so can only provide limited information on these procedures. It is therefore important for patients to be aware of the treatment options provided by IR.
These minimally invasive procedures carry lower risks than surgery, and have been fine-tuned to be as safe for patients as possible, with interventional radiologists maintaining high standards for safety and quality.
What are the benefits of interventional radiology?
Interventional radiology has a number of benefits for patients. The imaging techniques allow accurate diagnosis and treatment using cutting-edge equipment.
Minimally invasive procedures are performed through a small nick in the skin, minimising the patient’s discomfort and recovery time. As interventional procedures tend to require only local anaesthesia, hospital stays are very short, with patients frequently going home the day the procedure is performed. In addition, the techniques can be used in very sick patients who are unfit for surgery.
Patients who undergo IR procedures experience less pain during and after the procedure than patients undergoing surgical procedures. Post-procedural care is provided, along with follow-up imaging to confirm if the treatment has been successful.
Which imaging techniques are used in interventional radiology?
Angiography refers to real-time X-rays of arteries or veins following the injection of contrast material, which makes the vessels clearly visible under imaging. The contrast material is delivered through a thin catheter (tube) into a particular blood vessel and shows the inside of the vessel, allowing the interventional radiologist to locate blockages and problems within the vessel. Angiography is the primary method used to guide many IR procedures in the circulatory system, including angioplasty, embolisation and targeted delivery of chemotherapy.
A CT scan is an X-ray imaging test that provides detailed cross sections of the body’s internal tissues. The patient is given an injection of contrast material before the procedure to aid visualisation of the arteries and veins. 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). It can also often replace the need for traditional angiography to determine if a patient may benefit from angioplasty or stent placement for artery and vein occlusions.
Fluoroscopy uses X-rays to produce real-time moving images of the patient’s internal structure. The patient receives an injection of contrast material, which makes arteries, veins and blood vessels show up more clearly under X-ray. Fluoroscopy is used for guidance in a number of IR procedures, including angiography, discography and image-guided biopsy.
For MRA, the patient is placed in a magnetic field and then radio waves are used 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 function. MR guidance is used to provide real-time monitoring and temperature mapping without exposure to ionising radiation. However, it is not compatible with metal instruments, meaning that specialised instruments are required when the technique is used to guide IR procedures.
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, in a similar way to the use of SONAR by submarines. Ultrasound allows the physician see inside the body without using radiation, and is commonly used as the first method to check for vascular blockages and aneurysm. It also provides a robust guidance tool for many IR procedures such as biopsies, abscess drainage and tumour ablation.