Establishing a lesion is composed of fatty material can be achieved in a number of ways:
- Figure 1: Hounsfield measurement on CT (negative, typically around -90 to -110 HU)
- Figure 2: fat saturation results in fatty tissue losing all signal and appearing black (yellow arrows).
- Figure 3: chemical shift artefact on MRI T2 weighted image demonstrate chemical shift artefact around the lipoma in the frequency encoding direction (superior-inferior). Note how there is signal loss superiorly (black arrows) and hyperintensity inferiorly (white arrows). This is the result of inaccurate spatial encoding, resulting in the lipoma being incorrectly placed inferior to its actual location
- Figure 4: diagram of chemical shift artefact.