Interventional radiology (abbreviated IR or VIR for Vascular and Interventional Radiology) is a medical sub-specialty of radiology which utilizes minimally-invasive image-guided procedures to diagnose and treat diseases in nearly every organ system. The concept behind interventional radiology is to diagnose and treat patients using the least invasive techniques currently available in order to minimize risk to the patient and improve health outcomes.
As the inventors of angioplasty and the catheter-delivered stent, interventional radiologists pioneered modern minimally-invasive medicine. Using X-rays, CT, ultrasound, MRI, and other imaging modalities, interventional radiologists obtain images which are then used to direct interventional instruments throughout the body. These procedures are usually performed using needles and narrow tubes called catheters, rather than by making large incisions into the body as in traditional surgery.
Many conditions that once required surgery can now be treated non-surgically by interventional radiologists. By minimizing the physical trauma to the patient, peripheral interventions can reduce infection rates and recovery time, as well as shorten hospital stays.
Pooling of blood in the veins from weak valves resulting in enlarged, swollen vessels causing pain and cosmetic complaints. Interventional endovenous laser treatment or sclerotherapy may be used to heat the vein from the inside, sealing it closed. Other healthy veins carry blood from the leg to reestablish normal flow.
Peripheral artery disease (PAD)
Most commonly a result of atherosclerosis, occlusion of normal blood flow in the upper and lower extremities may result in pain, skin ulcers, or gangrene. Stenting, angioplasty, and mechanical atherectomy are available interventional treatments.
Deep vein thrombosis (DVT)
The formation of a thrombus, or blood clot, in the deep leg veins which may lead to swelling, discoloration, and pain. DVTs can result post-thrombotic syndrome and pulmonary embolism. Post-thrombotic syndromeis irreversible damage from a long standing DVT in the affected leg veins and valves, leading to chronic pain, swelling, and severe skin ulcers. Pulmonary embolism is a life-threatening condition which occurs when a deep vein thrombus (DVT) breaks off and travels to the lungs, resulting in difficulty breathing. Catheter-directed thrombolysis, balloon angioplasty, or stenting may be performed in the affected vein to dissolve the clot and restore normal blood flow.
A potentially life-threatening occlusion of the arteries supplying the lungs with blood clots, manifesting in shortness of breath, fatigue, palpitations, and fainting. Catheter-directed thrombolysis may be performed for this condition, where a catheter is inserted into the leg, threaded up to the lung, and then used to infuse “clot-busting” drugs into the occlusion.
IVC filter placement
Patients who have a history of, or are at risk for, pulmonary embolism may receive temporary or permanent inferior vena cava (IVC) filters to prevent the migration of blood clots to the lungs, and consequently prevent recurrence of pulmonary embolism.
Abdominal aortic aneurysms (AAA)
A weakening and dilatation of the abdominal aorta wall that can result in abdominal or back pain, and potentially life-threatening bleeding if it ruptures. Interventional treatment of this condition via non-surgical means is endovascular aneurysm repair, using angiography and stenting to occlude the AAA and prevent its continued growth.
Thoracic aortic aneurysms (TAA) and Aortic dissection
Anuerysms, or dilatations, of the thoracic (chest cavity) aorta may be caused by atherosclerosis, syphilis, trauma, or multiple other conditions. Aortic dissections are tears in the thoracic aorta resulting from trauma or weakening of the aortic vessel walls from conditions such as hypertension, atherosclerosis, and congenital conditions such as Marfan syndrome. Interventional treatments for TAAs and aortic dissections utilize stent grafts, sometimes in combination with surgery, to prevent blood flow from enlarging the diseased area or rupturing the aorta.
Acute limb ischemia
The sudden disruption of blood flow to an arm or a leg due to arterial occlusion by a blood clot or other debris, potentially treated with catheter-directed thrombolysis or mechanical thrombectomy.
Acute mesenteric ischemia
A medical emergency resulting from interruption of the blood supply to the abdominal organs due to blockage of the mesenteric arteries or veins by thrombus, embolus, or aortic dissection. Treatment varies by etiology of the ischemia, but may include thrombolysis, stenting, or angioplasty.
Aneurysms of visceral arteries
Dilatation of visceral arteries supplying organs such as the spleen, liver, or gastrointestinal tract can result in pain and life threatening bleeding. Stenting, embolization, liquid occlusion, and thrombin injection are the available interventional therapies for these disorders.
Arteriovenous malformations (AVMs)
Aberrations in normal vascular anatomy treatable by embolization which may cause pain, bleeding, heart problems, or cosmetic concerns.
OncologicVarious interventional therapies exist to treat cancers. Tumor type, size, extent of disease, operator experience, and involvement of anatomical structures all factor into deciding which therapy is most appropriate. Some therapies, such as transarterial chemoembolization, block the blood supply to tumors. Other techniques–radiofrequency ablation (RFA), microwave ablation, cryoablation, irreversible electroporation (IRE), and high-intensity focused ultrasound (HIFU)– irectly damage the cancerous tissue. All of these treatments are delivered locally, minimizing damage to nearby tissue and avoiding the systemic side-effects of chemotherapy.
A neurological condition occurring when the brain is starved of oxygen and nutrients resulting from the blockage of blood vessels supplying it (ischemic stroke) or from bleeding (hemorrhagic stroke). Symptoms include language, motor, sensory, and vision deficits. Interventional neuroradiologists play a critical role in determining the type of stroke (ischemic or hemorrhagic) using non-contrast computed tomography (CT) imaging or magnetic resonance imaging (MRI), and then treating the stroke using minimally-invasive treatment, if possible. Strokes caused by blood clots can be treated by intra-arterial thrombolysis or by mechanical thrombectomy. Strokes caused by bleeding resulting from ruptured aneurysms may be treated by embolization, most commonly using tiny metal coils.
Carotid artery stenosis
A narrowing of the carotid artery supplying the brain which can lead to stroke and disability. Carotid artery stenting (CAS) is an alternative to surgical carotid endarterectomy (CEA) which may be performed in patients who have symptomatic carotid atherosclerotic disease but who are poor candidates for open surgery.
Stenting of the cerebral veins is currently being studied as a potential interventional treatment for M.S. Hepatobiliary
A condition in which the normal flow of blood through the liver is slowed or blocked by scarring (cirrhosis) or other damage (e.g. hepatitis). Patients with the condition are at risk of internal bleeding or other life-threatening complications. Transjugular intrahepatic portosystemic shunt (TIPS) formation is a minimally-invasive treatment to alleviate this impaired blood flow.
Bile Duct Obstruction
Patients with liver cancer, bile duct cancer, cholecystitis, cholangitis, or other hepatobiliary pathology may experience obstruction of bile ducts. Interventional radiologists commonly perform procedures such aspercutaneous transhepatic cholangiography (PTHC or PTC) to image these obstructions, and may treat these conditions using percutaneous transhepatic biliary drainage (PTBD), wherein catheters or stents are placed through the skin and into the bile ducts to drain the bile for prolonged periods of time or until surgery. Women’s Health
Uterine fibroids are non-cancerous growths of the muscular portion of the uterus which may cause pain and heavy bleeding. Interventional radiologists are able to perform non-surgical, minimally-invasive treatments of uterine fibroids, called uterine fibroid embolization (UFE), or uterine artery embolization (UAE), using real-time imaging. In this procedure, the interventional radiologist makes a tiny nick in the skin in the groin and inserts a catheter into the femoral artery. The physician guides the catheter into the uterine arteries that supply blood to the fibroid and then releases tiny particles through the catheter to occlude the blood supply of the tumor, causing it to shrink and die.
Fibroid embolization typically requires a hospital stay of one night. On average, 85-90 percent of women who have had the procedure experience significant or total relief of heavy bleeding, pain and/or bulk-related symptoms. Recurrence of fibroids treated by UFE is very rare.
Pelvic congestion syndrome
A condition caused by pooling of blood in the pelvic veins, possibly resulting in pelvic pain and lower extremity varicose veins. Interventional vein embolization is possible in some cases, eliminating the need for surgical removal of the ovaries and/or uterus.
One cause of female infertility is the blockage or narrowing of the fallopian tubes through which eggs pass from the ovary to the uterus. This cause of infertility may be diagnosed using selective salpingography and treated by opening the narrowing using a minimally invasive device such as a balloon.
Renal artery stenosis
A narrowing of the arterial supply of the kidneys which may result in high blood pressure (hypertension) orrenal insufficiency. Diagnosis of these conditions is made by measuring the diameter of stenosis, the blood pressure across the area of stenosis, renal vein renin sampling, and captopril challenge testing. Stenosis may be treated by balloon angioplasty or stenting.
Renal failure/Dialysis catheter placement
Patients in renal failure may require the placement of a hemodialysis catheter prior to initiating hemodialysis for renal failure.
Dialysis fistula/Arterio-venous graft clot
Dialysis fistulae and grafts may become occluded by blood clots, requiring an interventional “declot” procedure in which mechanical or chemical thrombolysis is performed to eliminate the clot.
Dialysis fistula/Arterio-venous graft failure
Dialysis fistulae and grafts may fail to “mature”, resulting in the need to image the fistula and potentially relieve any blockages using angioplasty.
Nephrostomy tube placement
In conditions where a blockage exists between the kidney and the urethra, such as with kidney stones, a tube may be placed into the kidney under imaging guidance to allow the drainage of urine and to prevent kidney damage. Other
Vertebroplasty and kyphoplasty, the percutaneous injection of biocompatible cement into fractured vertebrae, are two available treatments for vertebral fractures.
A condition in which blood flow through the vessels around the stomach is slowed or stopped, potentially resulting in bleeding. Interventional treatments include embolzation and balloon-retrograde transverse obliteration (BRTO).
Varicoceles and male infertility
A dilatation in the veins of the scrotum which can result in pain, swelling, and infertility. It is potentially treated interventionally using embolization and sclerotherapy.
Vascular access and management of specialized kinds of intravenous devices (IVs) (e.g. PICC lines,Hickman lines, subcutaneous ports, translumbar and transhepatic venous lines).
Drainage of fluid from various body compartments using catheters and drains placed through the skin (e.g., abscess drains to remove pus, pleural drains).
Gastrostomy tube placement
In instances where patients are unable to take food by mouth, a feeding tube may be placed through the skin and into the stomach using imaging guidance.
Samples of tissue may be required to identify the cause of certain diseases. Using imaging guidance, interventional radiologists may minimally-invasively reach underlying tissue using a small needle to pierce the skin and retrieve tissue samples from the target organ.
Minimally invasive procedures commonly performed in children include obtaining central venous access, gastrostomy tube placement, diagnostic angiography, biopsies, and percutaneous drainage.
Common IR procedures are:
Imaging the blood vessels to look for abnormalities with the use of various contrast media, including iodinated contrast, gadolinium based agents, and CO2 gas.
Opening of narrow or blocked blood vessels using a balloon; may include placement of metallic stents as well (both self-expanding and balloon expandable).
Placement of a tube into the gallbladder to remove infected bile in patients with cholecystitis, an inflammation of the gallbladder, who are too frail or too sick to undergo surgery
Placement of tubes into different parts of the body to drain fluids (e.g., abscess drains to remove pus, pleural drains)
Endovascular aneurysm repair
Blocking abnormal blood (artery) vessels (e.g., for the purpose of stopping bleeding) or organs (to stop the extra function e.g. embolization of the spleen for hypersplenism) including uterine artery embolization for percutaneous treatment of uterine fibroids. Various embolic agents are used, including alcohol, glue, metallic coils, poly-viny alcohol particles, Embospheres, encapsulated chemo-microsphere, and gelfoam.
Delivering cancer treatment directly to a tumour through its blood supply, then using clot-inducing substances to block the artery, ensuring that the delivered chemotherapy is not “washed out” by continued blood flow.
Embolization of tumors with radioactive microspheres of glass or plastic, to kill tumors while minimizing exposure to healthy cells.
Treatment aimed at dissolving blood clots (e.g., pulmonary emboli, leg vein thrombi, thrombosed hemodialysis accesses) with both pharmaceutical (TPA) and mechanical means
Taking of a tissue sample from the area of interest for pathological examination from a percutaneous or transjugular approach
Radiofrequency ablation (RF/RFA):
Localized destruction of tissue (e.g., tumours) by heating
Localized destruction of tissue by freezing
Vascular access and management of specialized kinds of intravenous devices (IVs) (e.g. PIC lines,Hickman lines, subcutaneous ports including translumbar and transhepatic venous lines)
nferior vena cava filter
Metallic filters placed in the inferior vena cavae to prevent propagation of deep venous thrombus, both temporary and permanent.
Percutaneous injection of biocompatible bone cement inside fractured vertebrae
Placing a catheter directly into the kidney to drain urine in situations where normal flow of urine is obstructed. NUS catheters are nephroureteral stents which are placed through the ureter and into the bladder.
Radiologically inserted gastrostomy or RIG:
Placement of a feeding tube percutaneously into the stomach and/or jejunum.
Dialysis access and related interventions:
Placement of tunneled hemodialysis catheters, peritoneal dialysis catheters, and revision/thrombolysis of poorly functioning surgically placed AV fistulas and grafts.
Placement of a Transjugular Intrahepatic Porto-systemic Shunt (TIPS) for management of select patients with critical end-stage liver disease and portal hypertension
Placement of catheters in the biliary system to bypass biliary obstructions and decompress the biliary system. Also placement of permanent indwelling biliary stents.
Endovenous laser treatment of varicose veins:
Placement of thin laser fiber in varicose veins for non-surgical treatment of venous insufficiency