Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Principles of diagnostic angiography
Angiography is a team sport and a successful angiogram depends on cooperation between the patient and the angiography staff (radiographer, nurse and doctor). A little understanding of the basic principles of angiography can vastly improve the standard of the final study. This chapter reviews the key areas in image acquisition and manipulation.
Digital subtraction angiography: basic principles
Digital subtraction angiography (DSA) uses a computer to subtract an image without contrast (mask) from a series of subsequent images acquired after contrast injection. Assuming that everything remained in exactly the same position, the resultant images show only the opacified blood vessels. These are clearly seen in high contrast as the underlying bone or soft tissue is not displayed. Unfortunately, any movement between the mask image and the contrast image will result in image degradation; bone edges and bowel are the worst offenders.
Most DSA examinations are performed with positive (iodinated) contrast media; however, negative (CO 2 gas) contrast can be used.
Digital subtraction angiography techniques
Although non-invasive modalities are rapidly replacing diagnostic catheter angiography, the techniques underpinning peripheral angiography are still important.
Multi-position DSA (MPDSA)
Angiography is performed in discrete sections, each with its own contrast injection. In peripheral angiography, this usually gives the best results at the expense of a slight increase in radiation dose.
You're Reading a Preview
Become a Clinical Tree membership for Full access and enjoy Unlimited articles
If you are a member. Log in here
