nonfatsuppressed

Nonfatsuppressed refers to imaging in which fat signal is not suppressed, leaving adipose tissue visible with its native signal intensity. In radiology and MRI contexts, the term describes sequences that do not apply fat-suppression preparation, preserving fat signal rather than removing it.

In MRI practice, fat suppression techniques are used to reduce or remove fat signal to improve visibility of water-based tissues or pathology. Nonfatsuppressed sequences retain the signal from fat, providing intact visualization of fat-containing structures and enabling direct assessment of anatomy where fat distribution is relevant.

Applications include anatomical assessment of fat-containing tissues such as bone marrow, subcutaneous fat, and lipomas; evaluation of fatty infiltration in muscles or liver when fat visualization is informative; and comparative imaging where distinguishing fat from edema or other fluids may be beneficial. These sequences are often used when the presence of fat itself is diagnostically important or when subsequent fat-suppressed images are planned for lesion characterization.

Limitations and considerations: preserved fat signal can obscure lesions or inflammatory changes that are more conspicuous on fat-suppressed or fat-water–separated images. Nonfatsuppressed images may have higher overall signal and are susceptible to chemical-shift artifacts at fat-water interfaces. In practice, nonfatsuppressed sequences are typically used alongside fat-suppressed or Dixon-based acquisitions to provide complementary information.

See also: fat suppression, Dixon technique, chemical shift imaging.