Radiology is not only diagnostics, but also treatment

What exactly is interventional radiology and how does it differ from "traditional" radiology?

Interventional radiology is a field of medicine that focuses on imaging-guided minimally invasive percutaneous procedures. It can be assumed that it is a combination of surgery and radiology. Radiology, on the other hand, simply means diagnostic imaging.

What imaging techniques are most commonly used?

Fluoroscopy is the most common one. It is a technique that uses X-rays to generate a moving, real-time image of the inside of the body. It resembles a movie. We can also use sound wave imaging (ultrasound), computed tomography (CT), and magnetic resonance imaging (MRI).

When did radiology evolve from a diagnostic tool into a treatment method?

This happened in the late 1960s, when peripheral angiography and then coronary angiography were developed. Radiologists and cardiologists performing such examinations observed stenoses in the coronary arteries. This prompted attempts to expand the lumen of arteries using endovascular techniques. The first successful attempt to dilate the (femoral) artery with Teflon catheters was carried out by Charles Dotter in 1964. Then, balloon catheters were introduced – the world's first balloon catheter for percutaneous transluminal coronary angioplasty (PTCA) was designed and made in the 1970s by Andreas Gruentzig (with the team). Gruentzig performed the historic, first successful coronary artery dilation procedure in a human using a double lumen PVCA catheter in September 1977 in Zurich. This event prompted a huge technological progress. And so, we've gone from catheters as thick as a cord to ones as thin as a hair, which are flexible, resilient, and durable. They allow safe passage through the vessel to a point very far along its cirumference. Over time, various other types of balloons were developed, followed by endovascular metal prostheses (stents) that enhanced the dilation effect. It was the 1980s. Since then, technological advances have made it possible to use minimally invasive techniques in increasingly innovative and diverse applications. 

So it all started with vasodilation procedures. And what led to interventional radiology becoming part of oncology? 

When radiologists began to visualize tumors in vascular imaging studies, the concept of embolization, that is, blocking the vessels that supply the tumor, was introduced. For example, embolization procedures for a kidney tumor have often been performed and continue to be performed today (especially preoperatively, to avoid major bleeding during surgery). The procedure involves the administration of an embolization agent to the main artery supplying the tumor through a catheter. At first, there were not many materials available. Spongostan was the primary one. Now, we have much better materials and methods. For example, the Transacatheter Arterial Chemoembolization (TACE) procedure is mainly used to treat liver cancer. The procedure involves a dual approach – we simultaneously administer embolization material and a chemotherapeutic agent directly to the tumor. A chemotherapeutic agent administered directly may act at high concentrations. The drug remains within the tumor longer due to embolization, which blocks the blood supply to the tumor (thereby reducing the blood flow).

We are talking about liver tumors… What other neoplasms can be treated with surgical radiology?

More and more. Currently, great emphasis is placed on performing the least invasive procedures wherever possible. And indeed, we are seeing more and more patients, because our technological capabilities are also improving. At our center, we perform ablations of liver, kidney, lung and adrenal tumors. We are preparing to perform ablation of bone tumors. We use various types of ablation – most commonly thermal ablation or cryoablation.

What do these types of ablation involve?

The main difference is the temperature we use. We may use high temperatures, in which case we refer to thermal ablation, or very low temperatures in case of cryoablation. 

What do such procedures look like in practice?

The goal of ablation procedures is to deliver a specific type of energy to the tumor as effectively as possible. Ablative needles are used for this purpose. Their design varies depending on the type of energy transmitted through them. Using such needles, we reach the very center of the tumor through a percutaneous puncture. We navigate to that area using computed tomography, ultrasound or MRI guidance. Sometimes one needle is enough, and sometimes we need several needles , which is usually the case in cryoablations. 

Can we say that, for example, cryoablation is better than thermal ablation or vice versa? 

What technique we use depends on the type of tumor, its location, and the organ. For tumors of the kidney or bone, we mostly use cryoablation, which involves freezing the tumor. This method is also often used in the treatment of patients with lung nodules. Thermal ablation is used in the case of liver tumors. 

You mentioned that there is currently a lot of emphasis on performing the least invasive procedures, including interventional radiology. What are their advantages compared to conventional surgery? 

Interventional radiology procedures place less strain on the body. They take less time, so they require a shorter period of anesthesia. There are no wounds or “open” peritoneum, which reduces the risk of bacterial complications. Finally, the recovery period is much shorter than with traditional surgery. 

However, conventional surgery is still used in most cancer patients. Why, if minimally invasive procedures have so many advantages?

First of all, it is not about replacing surgery with interventional radiology. Surgery remains the primary and best-studied treatment for many cancers, especially when the entire tumor can be safely removed. Ablation, on the other hand, is particularly valuable in properly selected patients, e.g., those with a small tumor, a limited number of metastases, contraindications to surgery, or when the goal is to preserve as much of the healthy organ as possible.

The problem is that minimally invasive methods are still not available evenly across Poland. There is a lack of specialized centers, adequate infrastructure, funding and interventional radiologists. Some patients are not even consulted for such treatment. Therapeutic decisions are still too often made without the participation of an interventional radiologist.

Therefore, we should not view surgery and ablation as mutually exclusive. These are complementary methods. The goal is for every patient to be evaluated by a multidisciplinary team and receive the treatment best tailored to their disease – sometimes it will be surgery, sometimes ablation, and sometimes a combination of several methods.

That being said, which cancer patients are eligible for tumor ablation?

Interventional radiology procedures are usually performed in "inoperable" patients. For example, if a patient has four small liver metastases, resection may be unsuccessful, while ablation is still possible. Therefore, the size and number of neoplastic lesions and their distribution are decisive. 

It is worth noting here that a multidisciplinary team always qualifies a patient for the procedure. An oncological patient must be evaluated from an anesthesiological perspective (whether they can be anesthetized for surgery), clinical perspective (whether their circulatory and respiratory systems fuction properly), surgical perspective (whether surgeons will be able to operate if there are complications), and, finally, radiological perspective.

Interventional radiology began with vascular procedures, which initially focused mainly on the coronary vessels. Can it also be used in the case of cerebral vessels, that is in the treatment of strokes? 

Of course, strokes are more and more often treated under imaging guidance. In the case of ischemic stroke, the vessel is closed by a clot with different mechanisms being responsible. It happens most commonly in the elderly due to decreased vascular flow, the presence of atherosclerotic plaques, stenoses and blood thickening. In such cases, we refer to an ischemic stroke. It usually occurs in the morning. A clot forms in the lumen of the vessel and needs to be removed. Interventional radiology offers two methods here. We may use a suction technique, which means that, under imaging guidance, we locate the clot, break it and use suction to remove it. The second method consists in inserting a special stent into the clot and, like with a corkscrew, "unscrewing" it from the vessel. 

Can such methods be applied to every stroke patient?

The feasibility of endovascular treatment depends primarily on the time that has elapsed since the onset of stroke symptoms and the condition of the brain tissue. 

The so-called therapeutic window is of key importance. In most cases, it is important to restore blood flow as soon as possible, but the qualification for the procedure is determined not only by the time, but also by the condition of the brain tissue assessed using imaging tests.

It is worth noting that some people, especially those with chronic arterial stenosis, develop the so-called collateral circulation, which partially compensates for ischemia. Therefore, brain tissue can remain viable for a longer period than the therapeutic window would indicate, and treatability remains available for a longer period.

Thus, before deciding on the procedure, we perform imaging tests, primarily computed tomography with the assessment of brain perfusion. The tests make it possible to check both the patency of the vessels and the condition of the brain tissue. We assess the irreversibly damaged area, the so-called infarct core, and the surrounding zone, that is at risk which is still salvageable, known as the penumbra. If the area of irreversible damage is small and the penumbra is large, it means that restoring blood flow may bring significant benefits to the patient.
These tests are especially important when it is not known exactly when the stroke occurred, for example when symptoms occurred during sleep. In such situations, the qualification for treatment is primarily determined by the brain condition visible on imaging, and not only by the time since the onset of symptoms.

What other treatments can be performed using interventional radiology methods?

We can treat gastrointestinal hemorrhage or complications of portal hypertension in patients with cirrhosis. One example is the TIPS procedure (transjugular intrahepatic portosystemic shunt), performed in patients with recurrent bleeding from esophageal varices. Under imaging guidance, we insert a catheter through the jugular vein into the hepatic venous system and create a connection between the portal vein and the systemic circulation. Thanks to this, the pressure in the portal system decreases, and the risk of subsequent hemorrhages becomes significantly lower.

We also perform a variety of procedures involving the bile ducts. These include procedures for the decompression of cholestasis, dilatation of strictures and stent implantation. If it is impossible to reach the bile ducts using endoscopic methods, these procedures are performed percutaneously.

In recent years, tremendous progress has also been made in the materials used during procedures. Modern biodegradable stents made of magnesium alloys are used more and more frequently. They keep the bile ducts open for several months and are then gradually absorbed.

Do Polish patients have access to modern interventional radiology at a level comparable to other European countries?

When it comes to the knowledge, skills and experience of doctors, they are equal to European ones. The problem is not the quality of specialists, but their number. About 3,000 radiologists work in Poland, with only about 160 specializing in interventional radiology. This is not a spectacular number. For comparison, in France there are 1250, and in Germany there are about 1600 interventional radiologists. Moreover, systemic barriers are still to be overcome. Some procedures are not properly priced, and modern equipment and materials are expensive. The lack of functional angiography devices and interventional tomography scanners is a major obstacle, one that is also evident at our center. The organization of care and referral of patients to specialized centers also remains a problem. In oncology, the Cancer Diagnosis and Treatment Card pathway improved the situation, but in many other areas there is still a lack of an efficient system for qualifying and transferring patients for treatment with interventional radiology methods. 

Interventional radiology is developing very dynamically. Where does this pace of change come from?

It results from huge technological progress. The development of interventional radiology is supported by manufacturers of medical equipment, catheters, stents and advanced imaging systems. These advances make it possible to perform increasingly precise procedures while reducing the burden on the patient.
Modern technologies make procedures safer and more comfortable for both patients and operators. At the same time, medicine is clearly moving towards minimally invasive techniques which help shorten hospitalization time and accelerate recovery.
Of course, there are limits to such development. There are situations in which conventional surgery will remain irreplaceable. However, the field of application of minimally invasive methods is constantly expanding.

Can artificial intelligence change interventional radiology?

It already supports us in planning and performing procedures. Advanced computer programs help determine the safest way to achieve a change, plan the course of a procedure and increase its precision.

However, artificial intelligence will not replace a doctor. The final decision is always up to the person who takes responsibility for the patient's treatment. Therefore, AI should be treated primarily as an advanced tool supporting the planning and implementation of procedures. Its importance will grow with the development of medical imaging and navigation systems.

Interview by Iwona Kołakowska
Photo by Michał Teperek
Communication and Promotion Office