Chapter 8: Diagnostic Imaging of the Vascular System

INTRODUCTION

Assessment of the vasculature has consistently been challenging for the clinician, most often relating to blood flow and vascular construct. While radiography frequently demonstrates the outline of major vessels as the fluid-filled “tube” absorbs at a different level than the surrounding tissues, the incomplete ability to isolate and provide context for this information frequently limited its value. When these vessels are changed, radiographic imaging frequently can be evidential (Figure 8-1). More complete evidence for more informed clinical decision making has evolved with the use of computed tomography (CT). Today, CT offers the ability to acquire various forms of three-dimensional reconstructions providing an incredibly rich context of a singular tissue, enabling clinical decision making at an enhanced level. Additionally, radiologists have continued to increase the application and utility of MRI for vascular assessment through newer forms of imaging sequences. We have presented some of these applications in a regional approach.

Head and neck vascularity is of great concern related to acute presentation of a CVA and the need for urgent determination of infarct to enable proper emergent care. Since initial patient management decisions are frequently dependent on the determination of hemorrhagic versus ischemic insult, CT is the primary modality to allow discrimination of the two events (Figures 8-2 and 8-3).^1,2 A preceding event in many cases is a transient ischemic attack, which may have a rapid onset and last only briefly with full recovery in as little as 24 hours. To better delineate vessels and blood flow, however, MR angiography is increasingly becoming the selected modality here and in many other areas of the body. A great example is its use in the carotid arteries to enable surgical planning or confirming adequate blood supply.^3,4 CT angiography may also be used (Figure 8-4 A, B). Additional remarkable detail of the intracranial circulation can be obtained by three-dimensional CT angiography (Figure 8-5).