Different Imaging Techniques Used in Interventional Radiology

Introduction:

Interventional radiology (IR) uses the guidance of imaging techniques for diagnosis and minimally invasive surgical procedures. A specialized doctor who performs image-guided procedures is called an interventional radiologist.

What Are the Types of Equipment Needed for Interventional Radiology?

Interventional radiology usually requires:

• Guided Wire - Guided wire is used to guide the catheters. It is inserted into the hollow needle at the target site of diagnosis or treatment.

• Puncture Needles - A puncture needle provides a way for the catheter through the skin into the blood vessels.

• Catheter - A catheter is a flexible, thin, hollow tube inserted into the blood vessels.

• Stent - A small metal tube connected to the end of the catheter to be placed into the narrowed blood vessels.

• Deflated Balloons - Deflated balloons are connected to the end of the catheter and are placed in the blood vessels, which will be removed after dilatation of the blood vessels by inflation.

• Coils - Coils are usually made of titanium used to stop the blood flow by creating a blood clot.

What Are the Imaging Techniques Used in Interventional Radiology?

• X-rays such as fluoroscopy and computed tomography (CT).

• Ultrasound.

• Magnetic resonance imaging (MRI).

What Are the Types of Interventional Radiology?

Interventional radiology is widely used in many diagnostic and treatment procedures.

Based on their use, it is classified into:

• Diagnostic, interventional radiology.

• Therapeutic interventional radiology.

1) Diagnostic Interventional Radiology:

Diagnostic IR is used in the detection of various abnormalities in the body. This procedure involves the image-guided biopsy for diagnosis or administering contrast material into the body for the detection of structural and functional abnormalities of hollow structures.

• Angiography: Angiography is an imaging technique in which a catheter is placed through a small cut into the artery. After that, the contrast agent is injected through the catheter, and a series of X-rays are taken as the contrast agent passes through the blood vessels.

• Biopsy: The biopsy is a diagnostic procedure in which imaging techniques are used to guide the process of collecting sample tissues from the body, which will be later viewed under a microscope.

2) Therapeutic Interventional Radiology:

• Balloon Angioplasty and Stent Placement: This procedure is used to treat narrowed or blocked coronary arteries. During this procedure, a thin, flexible tube called a catheter is inserted into the arteries through a small opening under the guidance of an imaging technique. The catheter has a deflated balloon with or without a stent at its end. Then the balloon is inflated at the blocked area, which makes the artery enlarged, and sometimes the stent is placed in the artery to hold the artery open, which improves blood flow.

• Embolization: Embolization is a medical procedure that uses gelatin sponges or beads (embolic agents) to block the blood vessels.

• Uterine Fibroid Embolization: In this procedure, under the guidance of an X-ray, usually fluoroscopy (X-ray video), they insert a catheter through the skin incision into the artery in the groin or wrist and advance it to the uterine artery. Small plastic or gelatin particles called embolic agents (polyvinyl alcohol [PVA] will be injected into the blood vessels that supply uterine fibroids. These particles block the tiny blood vessels supplying fibroids and make the fibroids shrink and die. This procedure is done in both the right and left uterine arteries through the same incision.

• Chemoembolization: Chemoembolization, also known as transarterial chemoembolization (TACE), has a contrast material (a special dye) injected into the catheter to locate the tumor site. Later, a mixture of anti-cancer medicine and embolic agents is injected into the catheter placed in the artery that supplies the tumor. This procedure blocks the blood vessels supplying the tumor.

• Cryoablation: During this procedure, a thin needle called a cryoprobe is inserted through the skin directly into the cancer site. After that, the liquid nitrogen or argon gas is pumped into the probe, which freezes the cancer cells and destroys them.

• Vertebroplasty: Vertebroplasty is a procedure in which a hollow tube called a trocar is inserted from the skin incision through the spinal muscles to the fractured vertebra. After that, the orthopedic cement is injected into the broken site, which will fix them.

• Gastrostomy: For the gastrostomy procedure, two minor cuts are placed on the belly. A laparoscope is inserted through one of the cuts, and through the other cut, a gastrostomy or G tube (feeding tube) is inserted into the stomach, which provides nutrition.

• Radiofrequency Ablation: This procedure uses a probe that is inserted through the catheter under the guidance of an imaging technique, from which heat is generated by radio waves that kill the cancer cells.

• Inferior Vena Cava Filter: For IVC placement, a catheter is passed through the small cut to the target area. After this, an IVC filter (a small metal filter) is placed in the blood vessel, which stops the blood clot from reaching the heart and lungs.

• TIPS: TIPS, or transjugular intrahepatic portosystemic shunt, is a medical procedure that uses image guidance for the placement of a stent which creates a connection between the portal vein and hepatic vein.

• Percutaneous Nephrostomy: During the percutaneous nephrostomy procedure, a catheter is placed directly into the kidney to drain the urine temporarily. This procedure is done for a person with a blocked ureter.

• Percutaneous Abscess Drainage: This is a medical procedure used to drain the infected fluid from the body. Under image guidance, a catheter is passed through the skin into the abscess to drain the fluid.

• Endovenous Laser Treatment: Endovenous laser ablation is a procedure used to treat varicose veins (enlarged veins of legs and feet). During endovenous laser ablation, a catheter is inserted into the affected veins, and a laser is passed through the tube, which generates heat and burns the cells of the abnormal veins.

• Cholecystostomy: Cholecystectomy is the surgical procedure to remove the gallbladder. In cholecystostomy, a thin, flexible tube with a small camera at its end called a laparoscope is inserted through the small incision. Under the guidance of a laparoscope, the affected gallbladder is removed.

What Are the Benefits of Interventional Radiology?

• The cost of therapeutic interventional radiology is less when compared to open surgical procedures.

• Risks with interventional radiology are less when compared to other surgeries.

• This procedure is more rapid and painless than other surgical procedures.

Conclusion:

Interventional radiology procedures are advances in medicine that often replaces open surgical procedures. This minimally invasive procedure involves less blood loss and thus plays an important role in bloodless medicine. Interventional radiology procedures usually require local anesthesia or sedation. Hence, it does not often require hospitalization. The recovery time in interventional radiological procedures is shorter.