All 3 Uses

CT scan
in
Mother Tongue, by Amy Tan
(Auto-generated)

My mother had gone to the hospital for an appointment, to find out about a benign brain tumor a CAT scan had revealed a month ago.†
*

CAT scan = a 3-dimensional X-ray image of part of the body using computerized axial tomography
Still, she said, the hospital did not apologize when they said they had lost the CAT scan and she had come for nothing.†
And when the doctor finally called her daughter, me, who spoke in perfect English — lo and behold — we had assurances the CAT scan would be found, promises that a conference call on Monday would be held, and apologies for any suffering my mother had gone through for a most regrettable mistake.†

Definitions:

(1) (CT scan)
a diagnostic medical test that uses X-rays to create a 3-dimensional image of part of the body

Computed tomography (CT) or computed axial tomography (CAT) are the same test by different names with CT being more common today.
(2) (meaning too rare to warrant focus)