CT scan w contrast. (They took 1,248 scans!) Was told at pre-surgery consult it was likely (85% chance) malignant, & likely would mean a radical nephrectomy. The surgeon at Mayo reviewed those scans more in-depth, and a member of his team called me ON A SATURDAY!! to share that the surgeon believed he had a 95% possibility of saving my kidney! And he did. Was confined to the kidney and removal of both Was with 'good margins'.