What is Interventional Radiology?

In radiology, medical imaging modalities are used to diagnose a patient’s condition accurately. These imaging techniques include computed tomography (CT), X-ray, fluoroscopy, ultrasound, and magnetic resonance imaging (MRI). Interventional radiology (IR) is a subspecialty that involves procedures and treatments with the guidance of these modalities.  The procedures are usually minimally invasive, using only small incisions or body orifices as entry points.  Image guidance during these procedures allows accurate placement of the needles, catheters, sheaths, and stents. 

Who are Interventional Radiologists?

Radiologists are licensed and medically-trained physicians who specialize in diagnosing patients with the guidance of medical images.  A radiologist is adept and knowledgeable in producing the optimal image using cutting-edge imaging technology.  To become a radiologist, an individual must complete four years of medical school, followed by a two-year internship program and a three to seven-year residency.  Radiologists may go through a two-year fellowship to become interventional radiologists. The number of years it takes to become an interventional radiologist may range from ten to thirteen years.  Interventional radiologists specialize in performing treatments, following a diagnosis made through medical imaging.  Depending on their training, interventional radiologists may specialize in one or more medical fields, including neuroradiology, nuclear medicine, pediatric radiology, interventional oncology, cardiology, and pain medicine. Individuals looking for interventional radiologists may refer to the Society of Interventional Radiology (SIR). This nonprofit organization may help patients look for a radiologist specializing in a particular field.  SIR members who are looking for fellowship training may also refer to SIR Fellowship (FSIR) programs. Interventional radiology procedures are divided into two classifications according to purpose (diagnostic or therapeutic). Some diagnostic radiology techniques can also be used as therapeutic procedures.

Interventional Radiology (IR) Procedures

  • Ablation is a procedure wherein dead tissues or tumors are destroyed by inserting needles through the skin. 
Ablation procedures use heat or chemical agents on the intended targets. Ultrasound images guide the radiologists to insert the needle accurately.
  • Aspiration is the retrieval of fluid or tissue samples by inserting a suction needle into a lesion, cysts, or tumor. Aspiration procedures are guided by fluoroscopy, MRI, CT, and ultrasound.
  • Balloon-occluded retrograde transvenous obliteration (BRTO) is used to prevent gastric variceal bleeding. 
In the event of dilated blood vessels caused by high blood pressure in the liver, a BRTO procedure blocks the dilated vessels. This procedure is guided by fluoroscopy. 
  • Biopsies use the guidance of ultrasound or CT for accurate needle placement into the organs. The needle collects tissue samples to allow doctors to evaluate the disease.
  • Catheter and stent insertions are commonly guided by X-ray images. However, some procedures may also use CT or MRI. 
  • Catheter and stent insertion is useful for removing blood clots in vascular structures (angiogram). 
This procedure starts with the patient being injected with an iodine-containing contrast medium (ICCM).  The medium makes the vascular system visible in X-ray images and allows physicians to view blood vessels, blood flow, organs, and other internal processes. 
  • Corticosteroid injections on tissues and muscles help relieve pressure, pain, or blockage caused by inflammation. This procedure uses ultrasound images as guidance.
  • Closure devices are an alternative to manual compression (usually taking four to six hours) of catheter insertion sites upon completion of IR procedures. This device allows the patient to move immediately after the procedure. 
  • Embolizations use small resin particles that block blood flow in affected vessels. This procedure helps save patients from blood loss. 
There are several types of embolization, including artery embolization, uterine fibroid embolization, varicocele embolization, and trauma embolization.
  • Foreign body retrieval uses a snap wire loose system to retrieve materials left inside the body during IR procedures.
  • Gastrostomy is performed by inserting a tube into the stomach. This procedure is performed with the guidance of an ultrasound. 
Depending on the condition, the opening can be used for gastric decompression, or it can be replaced with a feeding tube for nutritional support.
  • Hemodialysis access maintenance keeps the blood vessels and veins clear from blood clots or from becoming narrow. 
This procedure allows for continuous hemodialysis without the trouble of connecting opening routes to the hemodialysis filtering system. 
  • Percutaneous drainage uses a catheter to remove fluid, abscess, or air with X-ray or ultrasound guidance. 
Catheter sizes may vary depending on the site and amount of liquid or air. 
  • Thrombolysis uses a catheter to administer the medication directly to the blood clot. This procedure is used on blood clots on lower limbs and organs. 
Thrombolysis uses X-ray images for guidance.

Interventional Radiology (IR) Treatments

  • Angioplasty is a procedure wherein a stent or sheath is inserted into the vein. A balloon is inflated at the blockage site to decongest the blood vessel. 
Balloon angioplasty treatments usually start with an angiogram to locate the blockage. This procedure treats vascular diseases and peripheral arterial diseases, including myocardial infarction (heart attack), limb thrombosis, and deep vein thrombosis (varicose veins). 
  • Ascitic tap is used to drain fluid in a cavity, particularly the abdomen. This procedure is done to relieve pressure and pain or to analyze fluid for infections or diseases. 
During ascitic taps, the radiologist uses ultrasound images to help guide the needle to the fluid’s location.
  • Biliary drainage is a procedure wherein a stent is inserted through the skin and into the liver. Bile storages are present in the liver and gallbladder. Sometimes, the bile duct system can experience obstruction. A biliary drainage procedure uses X-ray images as guidance to relieve the ducts from congestion.
  • Bursal injections use needles to administer corticosteroids into the bursa, relieving inflammation or pain. 
The bursa is a soft tissue that is located in between two bone structures. The bursal injection technique may also be used on the knees and elbows.  Ultrasound images guide the needle to the correct location. 
  • Carotid stenting is used to increase blood flow in the brain. Obstruction of the carotid artery reduces blood flow to the brain, which may lead to a stroke. 
Carotid stenting lowers the likelihood of a stroke by inserting a stent into the carotid artery to decongest the area from plaque.  X-ray images help the radiologist accurately place the stent into the artery. 
  • Carpal tunnel ultrasounds can be used to diagnose carpal tunnel syndrome. The carpal tunnel contains the median nerve, which is prone to compression. 
A compressed median nerve can cause pain, numbness, and tingling sensations in the hand and fingers. This procedure uses the guidance of ultrasound images.
  • Cervical nerve root sleeve injections are used to treat arthritis pain or prolapsed discs by administering corticosteroids on the cervical nerve. 
This procedure is guided by a CT scanner to help the radiologist accurately locate the nerve.
  • Chemoembolization is performed by injecting the chemotherapeutic drugs directly into the tumor. This procedure requires guidance from X-ray images.
  • Endovascular treatment for cerebral vasospasm is used to prevent a ruptured aneurysm. The blood released into the brain can cause compression on the arteries, resulting in decreased blood flow (vasospasm). 
Endovascular treatments for cerebral vasospasm use the guidance of X-ray images.
  • Inferior vena cava filters prevent blood clots in legs from moving to the heart and lungs. 
Guided by X-ray images, administration of IVC filters are used as a preventive measure for pulmonary embolism or arterial thrombosis. 
  • Lumbar epidural steroid injections relieve the patient from chronic back pain or leg pain. CT or MRI guides this procedure for accurate needle placement.
  • Lumbar nerve root sleeve injections are used for back and leg pain caused by compression on the nerve. CT images are used for this procedure.
  • Nephrostomies are procedures that allow urine drainage in the event of a blocked ureter. A needle is inserted into the kidney with the guidance of an ultrasound.
  • Pleural aspirations are done to remove fluid in the lungs. This procedure can be guided by X-ray images, chest CT, or an ultrasound. 
  • Radiofrequency ablations are non-surgical and minimally invasive procedures that use heat to stop or reduce pain. 
This treatment may also be used to destroy tumors (tumor ablation). Imaging guidance used for the procedure are X-rays, MRI, CT, or ultrasound. 
  • Radioembolization is a treatment for liver cancer. This procedure uses X-ray images to guide the insertion of micro radioactive spheres into the liver and destroy cancer cells.
  • Uterine Fibroid Embolization (UFE) is performed to reduce benign tumors’ blood supply in the uterus. 
With the help of X-ray images, the radiologist inserts a tube into the groin area until it reaches blood vessels in the uterus. Polyvinyl alcohol is then injected to stop the tumor’s blood supply.  
  • Vertebroplasty is performed by injecting polymethylmethacrylate (plastic cement) into damaged vertebrae. 
This treatment is performed on individuals who have compromised spinal columns due to osteoporosis, bone tumors, or spinal malformations. MRI scans are used to guide the radiologist during this procedure.

Interventional Radiology (IR) Benefits

IR allows physicians to diagnose and treat certain conditions without the need for open surgeries. The absence of surgeries means patients go through less pain and shorter recovery time.  Depending on the condition, some procedures do not require hospital stays. Moreover, non-invasive procedures have less risk of complications. Many IR treatments are preventive measures for arterial diseases’ lethal outcomes, such as heart attacks, limb infractions, and ruptured aneurysms.   Moreover, in the event when traditional surgery or invasive treatments are too dangerous, IR treatment options may be presented. 

Job Description and Average Salary of Interventional Radiologists

According to the 2016 survey from the American Medical Group Association (AMGA), radiology is one of the highest-paid specialties in medicine (1) In the United States, full-time radiologists earn an average annual salary range of $592,750 to $610,500 Interventional radiologists’ salaries vary according to years of experience and location. Depending on the cost of living, the base salary may be higher in larger states (New York, Florida, Michigan) compared to smaller states (Iowa) (2) Radiologists and interventional radiologist jobs have higher job outlooks than other healthcare professionals due to the growing demand for diagnostic imaging services (3). Related job titles in radiology, such as radiologic technologists (radiographers), also have an increasing job outlook (4). Radiographers specialize in operating imaging equipment. Interventional radiologist’s job description includes analyzing patient records, preparing a comprehensive report, performing treatments following a diagnosis, and having excellent patient care. Attending annual scientific meetings and in-trainings among health professionals are also part of the job description. Due to the influx of new imaging technologies, radiologists are obligated to learn, review journals, and undergo training continually.  They can do this by registering with radiological societies, such as the Radiological Society of North America (RSNA) and the Society of Interventional Radiology (SIR). Interventional radiologists may also review scientific papers from the Journal of Vascular and Interventional Radiology (JVIR). The JVIR provides updated news on therapeutic interventions, disease management, and techniques.  The SIR Foundation also conducts annual meetings or virtual meetings to keep interventional radiologists updated on innovative therapies. Medical students and radiologists interested in becoming interventional radiologists may refer to the Society of Interventional Radiology website at www.sirweb.org

History of Interventional Radiology (IR)

The first arteriograms were performed in 1953 when surgeons presented an ingenious method to look at the vascular system without surgery.  A catheter was used to inject sodium iodide into blood vessels. The sodium iodide would be distributed into the vascular system and become visible through X-ray (5). This procedure became a clinical practice that was developed during the ‘60s and ‘70s. Some hospitals called it a “specialty procedure” or “angiography.” The objective was to evaluate tumors, blood vessels, veins, lymphatics, tissues, or organ structure (6) During its beginnings, the purpose of the procedure allowed physicians to study the condition, conduct vascular mapping, or search for trauma before a surgical procedure. Interventions were non-existent at the time. In 1963, the first scientific paper for the IR procedure was written by Dr. Charles T. Dotter. The article mentioned the potential of using catheters to perform intravascular procedures (7) By the mid-‘70s, the transcatheter techniques became a standard practice. These IR procedures were angioplasty, embolizations, and vasoconstrictor infusions (8). The technique of arterial angioplasty would continue to be accepted throughout the medical community. By 1980, therapeutic procedures in radiology were introduced (9)

Conclusion

Medical imaging allows interventional radiologists to improve a patient’s quality of life without invasive procedures.  Due to new technologies, new techniques are regularly introduced. Interventional radiologists must continuously keep themselves updated in the latest advancement in medical imaging and therapies. The future of interventional radiology is expanding, and job outlooks are also rising due to increasing demand (10) All these factors are why interventional radiology is considered to be at the forefront of modern medicine (11).
  1. American Medical Group Association. Productivity Survey. Retrieved from https://www.amga.org/performance-improvement/best-practices/benchmarking-surveys/compensation-survey/
  2. Ibid
  3. US National Labor Statistics Prediction. Retrieved from https://www.bls.gov/ooh/healthcare/physicians-and-surgeons.htm#tab-6
  4. US National Labor Statistics Prediction. Retrieved from https://www.bls.gov/ooh/healthcare/radiologic-technologists.htm#tab-6
  5. Brooks B. Intra-Arterial Injection of Sodium Iodide: Preliminary Report. JAMA. 1924;82(13):1016–1019. doi:10.1001/jama.1924.02650390006002
  6. Murphy, T. P., & Soares, G. M. (2005). The evolution of interventional radiology. Seminars in interventional radiology, 22(1), 6–9. https://doi.org/10.1055/s-2005-869570
  7. Ibid
  8. Ibid
  9. Ibid
  10. US National Labor Statistics Prediction. Op cit.
  11. Midulla, M., Pescatori, L., Chevallier, O., Nakai, M., Ikoma, A., Gehin, S., Berthod, P. E., Ne, R., Loffroy, R., & Dake, M. (2019). Future of IR: Emerging Techniques, Looking to the Future…and Learning from the Past. Journal of the Belgian Society of Radiology, 103(1), 12. https://doi.org/10.5334/jbsr.1727

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