Can a ct scan of the neck without contrast give meaningful information on a lump? i am breastfeeding.

Absolutely.: Trust your physician on this. The ct scan can more clearly identify the dimensions and depth of this lump. Also, it can detect if this lump has tentacles or is attached to other important structures in your neck. It can help detect if the lump is solid or cystic; this would lead the surgeon as to whether the lump would need to be removed entirely or perhaps tolerate a needle aspiration or biopsy.

Yes: It can definitely help. A ct with contrast is better. If you're worried about breast feeding with the contrast, its not an issue. The amount that is actually eventually absorbed by the baby from the stomach is extremely small. Much less than we give babies actually getting a ct scan.