Cross-Sectional Vascular Imaging

Multidetector CT Angiography (MDCTA)

• Rapid IV injection of contrast (3-5 mL/s) ▸ automated contrast bolus detection techniques: the ‘arrival of contrast medium is measured within a vessel at a single level, and data acquisition initiated when a certain density threshold is reached

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    Multiplanar reconstruction (MPR): useful for the rapid review of blood vessels in any plane (and assessment of vessel walls that might be obscured in MIP and VR techniques ▸ curved MPR allows tortuous vessels to be ‘straightened’

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    Maximum Intensity Projection (MIP): produces a planar image from a volume of data within which the pixel values are determined by the highest voxel value in a ray projected along the data set in a specified direction ▸ mimics a conventional arteriogram ▸ however tissue of high density (e.g. bone) will be reprojected in the final image and may misrepresent a blood vessel

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    Volume Rendering Techniques (VR): assesses the entire volume of data with an attenuation threshold for display producing a 3D image (final images can be rotated) ▸ vascular stenosis can be overestimated

• Preferred for vascular aneurysm assessment over MRA as more sensitive for detecting wall calcification