Intravascular Angioscopy

 

Introduction

  • Percutaneous angioscopy, using high resolution fiberoptic imaging, allows direct and two-dimensional visualization of the vascular interior, thereby enabling macroscopic pathological diagnosis. 
  • Percutaneous angioscopy has revealed that the vascular luminal surface exhibits various colors and morphologies characteristic of different vascular diseases. 
  • This imaging technique is used for evaluation of:
    • The severity of vascular diseases
    • Staging of atherosclerosis
    • Analysis of thrombus composition
    • Evaluation of interventional and surgical therapies
    • Guidance of intravascular interventions such as angioplasty, venous valvuloplasty and aortic stent-grafting
  • The procedure starts by inserting a flexible fiberoptic guidewire into a large artery  through a catheter.
  • Angioscopy is able to detect plaque features based on colour characteristics.
  • For clear visualization, the vessel has to be occluded and the remaining blood flushed  away with saline solution (sodium chloride solution).

Percutaneous angioscopy

Visualized plaque features by coronary angioscopy

Advantages

  • Assess Plaque Color And Surface Characteristics. 
  • Plaque color by coronary angioscopy can be graded as its yellowness: 

coronary angioscopy

  • Morphology of plaques is also evaluable by coronary angioscopy. 
    • Stable plaque is lesion with smooth surface.
    • Complex plaque exhibits an irregular surface. 
  • Ruptured plaque, eroded plaque, intimal flap, fissure and ulceration are another complex lesions identified by coronary angioscopy. 
  • The sensitivity for the detection of thrombus is almost 100% under angioscopy imaging.

Limitations of angioscopy

  1. It is difficult to conduct quantitative analysis of plaques based on the color and volume. 
  2. Coronary angioscopy images only surface of the coronary lumen (it can not examine the different layers within the arterial wall). 
  3. It requires displacement of blood within coronary arteries by injecting saline continuously.
  4. Limited access to the arterial tree due to the size of its device.