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Definition:
Images acquired before intravenous contrast administration.
Comments:
- Pre-contrast imaging is required for MRI and suggested for CT.
- Should be acquired, if possible, with same acquisition parameters as post-contrast imaging.
- Used to determine intrinsic attenuation/T1 intensity of observations relative to reference tissue such as liver.
• At CT: this may provide information on presence and distribution of fat, iron, calcification, blood products, and, if post embolization, iodized oil.
- Used as baseline to gauge enhancement on post-contrast images
• At MRI, pre-contrast images may be subtracted from arterial phase images. For observations that are hyperintense pre-contrast, such subtractions may help in the assessment of arterial phase enhancement.
• For subtractions to be valid, arterial phase and pre-contrast images need to be acquired with the same technique.
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