Exams
Scanner, CAT scan and computed tomography are the same exam: how to read the order you are holding
Four names for one service. The doctor says scanner in the consulting room, writes TAC on the paper, the fee schedule lists it as tomografía computarizada, and the patient searches for tomografía computada. Every door leads to the same machine, and only one of them is indexed in the system where appointments are requested.
What do the words on the order mean?
- TAC and TC: the same service. The A stands for axial and survives from older machines.
- Scanner: the word used out loud in the consulting room. Plenty of people also use it for an MRI, and that is where the confusion starts.
- Angio, pyelo or uro in front of the name: different protocols, with their own preparation and supplies. A chest CT angiogram and a chest CT are separate codes.
- With contrast or without: the most expensive phrase on the order and the one most often lost.
Why does contrast change the appointment so much?
Because in CT the contrast is billed and prepared separately. The FONASA fee schedule states it in the header of its computed tomography section: the listed prices do not include the contrast medium. The MRI section of the same document says the opposite about itself. Two sections, two rules.
For the patient that becomes extra admin: a quote, sometimes an authorisation, and always a history check before the line goes in. It is the point where the medical order stops moving on its own.
How is it different from an MRI or a plain X-ray?
CT and plain radiography share X-ray technology; CT uses it to reconstruct slices instead of a single projection. An MRI works with a magnetic field and radio waves, and its appointment block is longer. When someone says they were sent for a scanner, it is worth reading the paper before calling for a slot.
What does the centre need before the appointment?
The order with the exact region.
Abdomen and pelvis is a different service from abdomen alone, with its own code and its own price.
The answer on contrast.
If the order carries it, the centre applies its own contrast medium protocol: what it checks, what it asks, what it has you sign.
The centre's fasting instructions.
The RSNA reference on CT says patients are told not to eat or drink for a few hours before the procedure, and the exact hours are set by each institution. Check the fasting rule of the place treating you rather than assuming somebody else's.
The pregnancy notice.
The same reference asks patients to speak with their doctor if there is any possibility of pregnancy, before the exam.
How long does it take?
Image acquisition is brief. What stretches the visit is everything around it: registration, changing, placing the line when contrast is used, and the observation period afterwards. A study without contrast fills a short block; one with contrast fills twice that or more, which is why centres schedule them at different hours.
Why does this order get lost?
Because of the name and because of the price, in that order. The name fails in the centre's search box; the price fails when the patient learns at the counter that contrast is billed separately and decides to come back another day. That other day feeds the waiting list without being recorded anywhere.
Some centres already run that follow-up themselves and write to the patient before the order goes cold. Ask at yours whether they use Surface.