What CT Angiography and MR Angiography Are
3-D imaging of the cerebral vasculature employs imaging technology to create computerized
three dimensional models of the blood vessels. These 3-D models help the radiologist more
accurately define morphology of blood vessel anatomy in diseases such as aneurysms, intracranial
or extracranial vessel stenosis, and stroke.
Catheter angiography is the traditional method for studying blood vessels; however, newer
non-invasive methods, ie: CT angiography and MR angiography, are becoming more frequently
utilized as a non-invasive alternative for studying intracranial and extracranial vasculature.
These newer methods use computed tomography and magnetic resonance imaging technologies to
evaluate the cerebral blood vessels in completely non-invasive ways. CT angiography uses an
intravenous contrast agent to enhance the visibility of the blood vessels. Similarly, MR angiography
often uses intravenous contrast agent. Computer generated images allow a “model” of the blood
vessels to be created, and have the ability to be viewed in infinite projections. This has proven
invaluable in planning treatments of vascular diseases.
CT angiography and MR angiography are particularly useful in imaging the blood vessels of
the brain. When a patient comes into the hospital with bleeding in the brain, these tests
are often the first performed to identify the source of the problem and plan treatment. For
most emergent cases, CT angiography is preferred over MRA given the short imaging time
necessary to complete the study. This is particularly helpful in evaluation of acute stroke patients.
RIA radiologists interpret the results of these complex exams at several Denver area hospitals.