Ct scan showed spot on liver, have colon cancer but ultrasound came back negative does it mean it was wrong?

Spots: There are a variety of things that can be seen in the liver. Not all of them are metastatic tumors. You can have benign nodules. However, ct is a better way of viewing the liver. It is difficult to know what the spot is without reading your radiology reports. I would clarify with your doctor.

Not necessarily: Ct and ultrasound are complimentary for imaging the liver. Some lesions may be inaccessible to ultrasound evaluation. Some lesions may show up clearly on sono but not at all well on ct. If the lesion seen on ct was definite, and a new finding, you may need a ct guided liver biopsy in view of your history of colon ca. Good luck.

Pet or MRI may help: Other imaging modalities may help further clarify if this finding in ct is suspicious for malignancy or more likely benign if the ct and ultrasound have not been more specific. If u have older ct scans to compare and this is indeed new, then further clarification is needed. This all has to be taken into context of the bigger clinical picture including CEA as well as the rest of your body.