Interventional radiology is abbreviated IR or sometimes VIR for vascular and interventional radiology, also known as Image-Guided Surgery. It is a subspecialty of radiology in which minimally invasive procedures are performed using image guidance. Some of these procedures are done for purely diagnostic purposes (e.g., angiogram), while others are done for treatment purposes (e.g., angioplasty).
The basic concept behind interventional radiology is to diagnose or treat pathology with the most minimally invasive technique possible. Images are used to direct interventional procedures, which are usually done with needles and narrow tubes called catheters. The images provide road maps that allow the interventional radiologist to guide these instruments through the body to the areas containing disease. By minimizing the physical trauma to the patient, peripheral interventions can reduce infection rates and recovery time as well as shorten hospital stays.
Common interventional imaging modalities include fluoroscopy, computed tomography (CT), and ultrasound (US). These methods have the advantages of being fast and geometrically accurate. Other common IR procedures are:
- Angiography: Imaging the blood vessels to look for abnormalities.
- Balloon Angioplasty/Stent: Opening of narrow or blocked blood vessels using a balloon; may include placement of metallic stents as well.
- Chemoembolization: Delivering cancer treatment directly to a tumor 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.
- Cholecystostomy: 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.
- Drain Insertions: Placement of tubes into different parts of the body to drain fluids.
- Embolization: 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.
- Thrombolysis: Treatment aimed at dissolving blood clots (e.g., pulmonary emboli, leg vein thrombi, thrombosed hemodialysis accesses).
- Biopsy: 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., tumors).
- Line Insertion: 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).
- IVC Filters: Metallic filters placed in the inferior vena cava to prevent propagation of deep venous thrombus, both temporary and permanent.
- Vertebroplasty/Kyphoplasty: Percutaneous injection of biocompatible bone cement inside fractured vertebrae.
- Nephrostomy Placement: 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 Intervention: Placement of tunneled hemodialysis catheters, peritoneal dialysis catheters, and revision/thrombolysis of poorly functioning surgically placed AV fistulas and grafts.
- TIPS: Placement of a Transjugular Intrahepatic Porto-systemic Shunt (TIPS) for management of select patients with critical end-stage liver disease and portal hypertension.
- Biliary intervention: Placement of catheters in the biliary system to bypass biliary obstructions and decompress the biliary system. Also placement of permanent indwelling biliary stents.
- Cerebral Angiography: Imaging blood vessels in the head.