Chapter 27: Vascular, Cardiac, & Interventional Radiography

Detailed Chapter Overview

Chapter 27 explores the highly specialized and dynamic fields of vascular, cardiac, and interventional radiography. These advanced procedures involve the opacification of vessels and organs to diagnose and, increasingly, to treat a wide range of pathologies. This chapter is essential for understanding the transition of radiography from a purely diagnostic modality to a therapeutic one. The central theme of the chapter is angiography—the radiographic examination of vessels following the injection of contrast media. It provides a deep dive into the foundational **Seldinger technique** for arterial access, a cornerstone of all modern angiographic and interventional procedures. The chapter meticulously details the roles and responsibilities of the entire angiographic team, emphasizing the critical importance of sterile technique, patient monitoring, and radiation safety in this high-risk environment. A significant portion is dedicated to specific diagnostic procedures, from cerebral angiography to detect aneurysms to coronary angiography to assess heart disease. The chapter then transitions to the field of interventional radiology (IR), showcasing how angiographic techniques are used to perform minimally invasive therapies, such as embolization to stop bleeding, angioplasty and stenting to open blocked vessels, and filter placement to prevent pulmonary emboli. For every procedure, the text provides a detailed overview of the clinical indications, equipment, and the specific role the radiographer plays in producing the high-quality images necessary for guiding these complex interventions.

In-Depth Study Guide

Foundations of Angiography

Angiography is the general term for the radiographic examination of blood vessels after the injection of a contrast medium.

1. Key Terminology

• Angiography: Examination of vessels (both arteries and veins).
• Arteriography: Examination of arteries.
• Venography: Examination of veins.
• Cardiac Catheterization: An advanced procedure to image the heart and its associated vessels, specifically the coronary arteries.

2. The Angiographic Team and Room

• The Team: These complex procedures require a specialized team, typically including a radiologist or cardiologist, a radiographer specializing in interventional procedures (the "scrub tech"), a circulating nurse, and an anesthesia provider if needed.
• The Angiography Suite: A specialized room that combines a patient procedure table with sophisticated fluoroscopic imaging equipment, often with bi-plane (two C-arm) capabilities to acquire simultaneous AP and lateral images.

3. The Seldinger Technique: The Cornerstone of Arterial Access

Developed in 1953 by Dr. Sven-Ivar Seldinger, this technique is the standard method for gaining safe access to the vascular system. It is a fundamental skill that underpins nearly all angiographic and interventional procedures.

Step-by-Step Process:

1. Puncture: The physician makes a small puncture through the skin and into an artery (most commonly the **femoral artery** in the groin) with a sharp, hollow needle.
2. Guidewire Insertion: A flexible, soft-tipped guidewire is inserted through the needle and advanced into the vessel.
3. Needle Removal: The needle is withdrawn over the guidewire, leaving the guidewire in place inside the artery.
4. Catheter Introduction: A catheter (a long, thin, flexible tube) is then threaded over the guidewire and advanced into the artery. The guidewire provides the path for the catheter to follow.
5. Guidewire Removal: Once the catheter is in the desired location, the guidewire is removed, leaving the catheter in place for contrast injection or other interventions.

Diagnostic Angiography Procedures

Digital Subtraction Angiography (DSA) is a common technique where a "mask" image is taken before contrast injection. This mask is then subtracted from the subsequent images containing contrast, effectively removing the overlying bones and soft tissues and leaving only the opacified vessels visible.

• Cerebral Angiography: Used to visualize the blood vessels of the brain to diagnose conditions like aneurysms, arteriovenous malformations (AVMs), and stenosis.
• Thoracic Aortography: Visualizes the thoracic aorta to assess for aneurysms or dissections.
• Abdominal Aortography & Visceral Arteriography: A catheter is placed in the abdominal aorta to evaluate for aneurysms, stenosis, or to selectively catheterize specific arteries like the renal, celiac, or mesenteric arteries to investigate organ-specific issues.
• Peripheral Angiography: Involves imaging the arteries of the upper or lower limbs. A "runoff" procedure in the legs is common to evaluate for peripheral artery disease (PAD) in patients with leg pain or non-healing ulcers.

Cardiac Catheterization and Interventional Cardiology

• Purpose: A specialized procedure performed by a cardiologist to evaluate the heart's chambers, valves, and coronary arteries.
• Diagnostic Applications:
  • Coronary Angiography: The primary method to visualize blockages (stenosis) in the coronary arteries, which is the cause of most heart attacks.
  • Hemodynamic Assessment: Measuring pressures within the heart chambers and across valves.
• Therapeutic Interventions (Coronary):
  • Percutaneous Transluminal Coronary Angioplasty (PTCA): A balloon-tipped catheter is inflated within a narrowed coronary artery to compress the plaque and widen the vessel.
  • Stent Placement: Following angioplasty, a small, wire-mesh tube called a stent is often deployed to act as a scaffold, keeping the artery open.

Interventional Radiology (IR)

Interventional radiology uses minimally invasive, image-guided procedures to diagnose and treat diseases in nearly every organ system. It is often described as "surgery without a scalpel."

Common Interventional Procedures:

• Transcatheter Embolization: The intentional blockage of a blood vessel. A catheter is guided to the target vessel, and embolic agents (coils, particles, or glue) are deployed to stop blood flow. This is used to control bleeding (e.g., from trauma or a GI bleed), treat tumors by cutting off their blood supply, or close off AVMs.
• Percutaneous Transluminal Angioplasty (PTA) and Stenting: The same angioplasty and stenting techniques used in the heart can be applied to other arteries in the body, such as the renal arteries or the arteries in the legs.
• Inferior Vena Cava (IVC) Filter Placement: For patients with blood clots in their legs (deep vein thrombosis or DVT) who cannot take blood thinners, a small, umbrella-like filter is placed in the IVC via a catheter to catch any clots traveling toward the lungs, thus preventing a life-threatening pulmonary embolism.
• Transjugular Intrahepatic Portosystemic Shunt (TIPS): A complex procedure for patients with severe liver disease and portal hypertension. An interventional radiologist creates a shunt (a new pathway) through the liver to connect the portal vein directly to the hepatic vein, reducing pressure and preventing complications like variceal bleeding.
• Non-vascular Interventions: IR also includes procedures that don't primarily involve vessels, such as percutaneous abscess drainage, nephrostomy tube placement (draining a blocked kidney), and image-guided biopsies.

The Radiographer's Role and Radiation Safety

The radiographer in the interventional suite is a highly skilled professional responsible for operating complex imaging equipment, managing images, and ensuring radiation safety.

• Equipment Operation: Expert knowledge of the C-arm, power injector, and digital subtraction software is required.
• Patient and Staff Safety: These procedures can involve long fluoroscopy times. The radiographer must diligently use all radiation protection measures:
  • Utilize pulsed fluoroscopy and last-image-hold to minimize beam-on time.
  • Use tight collimation.
  • Ensure all personnel in the room are wearing lead aprons.
  • Use protective lead shielding (table skirts, ceiling-suspended shields) whenever possible.