Interventional Radiology: Treatment, Effects & Risks

Interventional radiology is a relatively new subspecialty of radiology. Interventional radiology performs therapeutic tasks.

What is interventional radiology?

Interventional radiology is the therapeutic subspecialty of diagnostic radiology. This fact may seem quite bizarre, but it goes back to the fact that interventional radiology is still a fairly young subfield of radiology. For this reason, at least in Germany, it has not yet been able to separate itself from diagnostic radiology. In the Anglo-Saxon world, however, interventional radiology represents a separate specialty alongside diagnostic radiology. The task of interventional radiology is to perform interventions under image guidance (e.g. by CT, MRI or sonography). These interventions are usually performed on the vascular or biliary system or on other organs that perform a function. Constant evolution of diagnostic radiology, its tasks, and its procedures must be observed.

Treatments and therapies

Interventional radiology treats various diseases and conditions by invasive procedures under image guidance. Thus, the methods of radiology are generally used in this regard. Historically, the history of interventional radiology began with invasive therapy for vascular disease. Prior to this, radiologists had succeeded in imaging the human vascular system using special angiography catheters. This success initially led to the idea of treating vascular diseases by balloon dilatation or by metallic vascular supports (“stents”). Interventional radiology developed from these basic ideas. This was thus initially developed as a minimally invasive therapeutic option for cardiovascular diseases. Later, interventional radiology underwent further development. Thus, the spectrum of this was expanded to include complex clinical pictures and the treatment of tumor diseases. Today, there are various interventions that are performed by interventional radiology. What all these interventions have in common is that they are image-guided and/or performed using the methods of radiology. The interventions can be differentiated according to the location of the intervention and the respective image control. Thus, vascular interventions, tumor ablative interventions, biliary interventions, and CT-, MRI-, and ultrasound-guided interventions can be primarily distinguished. Some of the most common interventions in interventional radiology are briefly discussed below.

  • Angioplasty: Angioplasty is a procedure in the field of vascular inventions. Angioplasty involves recanalization of an occluded vessel with the aid of a metallic vascular support (“stent“) or by balloon dilatation. However, angioplasty is not only performed by interventional radiology, but also by interventional cardiology and neuroradiology. Here, interventional cardiology supplies the cardiac vessels, neuroradiology supplies the intracranial and brain-supplying vessels, and interventional radiology supplies all peripheral vessels. These also include mesenteric and retroperitoneal vessels in humans.
  • Chemoembolization: chemoembolization is also a vascular intervention. It is a nonsurgical therapy for malignant tumors of the liver. First, the vessels supplying the tumor are identified under X-ray fluoroscopy. A chemotherapeutic agent is applied to the tumor-supplying tissue. Subsequently, the vessel is occluded. This is done by embolization. The tumor can thus no longer be supplied with blood, and thus with nutrients and oxygen. In addition, the chemotherapeutic agent is prevented from escaping from the tumor tissue.
  • Thrombolysis: Thrombolysis is an emergency treatment procedure to reopen a thrombosed vessel. This can be done by instillation of clot-dissolving drugs into the affected vessels or by destruction of the blood clot.
  • Cryoablation: cryoablation is a tumor ablative intervention. Cryoablation involves the use of cold to destroy a tumor. The cold is applied only locally at the site of the tumor.
  • Drainage system: drainage system is classified as image-guided procedures.In this, drainage catheters are applied to drain inflammatory and non-inflammatory fluids from the body.

Diagnosis and examination methods

First, it should be said that interventional radiology is the therapeutic branch of radiology. Diagnoses are made by diagnostic radiology, not by interventional. Roughly, it can be said that diagnostic radiology only diagnoses and does not treat; interventional radiology, on the other hand, only treats but does not diagnose. The equipment used in interventional radiology is the technical equipment used for diagnostic imaging. These serve the physician in interventional radiology to get an overview of the situation and to be able to observe the processes of the intervention. The physician is dependent on the imaging devices because he cannot observe his actions directly but only via the imaging devices. Thus, the imaging devices serve to “control” the procedure. Furthermore, in most cases, interventional radiology uses catheters to enter the body. Medication-wise, interventional radiology primarily uses chemotherapeutic agents. This is done as part of minimally invasive tumor therapy. Here, a chemotherapeutic agent is first injected directly into the tumor tissue in order to subsequently ‘cut off’ its blood supply. This serves to cut off the supply of oxygen and nutrients to the tumor and also ensures that the chemotherapeutic agent does not leave the tumor tissue. This procedure is called chemoembolization and is used to treat malignant liver tumors.