For patients with central hypothyroidism and a clear etiology (such as recent head irradiation), do you recommend brain imaging prior to starting thyroid hormone replacement therapy?  

Levothyroxine does not cause tumor growth, and therefore you do not need to image before starting therapy. However, in general, it takes a long time for central hypothyroidism to develop after radiation, therefore in the presence of an early reduction in FT4 you must consider the possibility of the ...

Only if they have other pituitary hormone deficiencies.