MRI or CT bit confussed ?


Just wanted to ask why some of us are sent for MRI & some CT ? my onc is going to arrange a ‘scan’ after my rads are finished Ive had a CT back in my teens & had a bad reaction to the dye injected … can they do these without the dye or is that standard procedure. He didn’t say which one id be having & only thought of it when he see Id not had one yet. Can the whole body be checked with an MRI ?

Thank you
Mekala x

They are both different, the physics is different. The MRI can provide a higher definition of image but takes a lot longer and isn’t so comfortable.
The MRI was the only diagnostic test that found my primary - it didn’t show on mammo, u/s nor CT scan.

You still have to be injected with a contrast agent for the MRI, this is done via a cannula. The agent is different; I didn’t get the feeling that I’d wet myself which everyone gets with the CT injection.

Hi Mekala

It’s very likely to be a CT scan. I had one yesterday. I don’t have any problems with the dye but since I’ve had my portacath removed they’re back to playing hunt the vein! After 3 unsuccessful attempts I asked if they ever did a CT scan without contrast and they said no, there wouldn’t be any point.

MRI’s are more expensive, very slow - and I think are rarely used for the whole body. It took an hour to do my spine. CT scans take about 5 minutes - but again they usually just do the torso.

Ninja - interesting that you had dye for an MRI. I’ve had 3 without dye - but maybe it depends what they are looking for. Mine were bone related.

You definitely need to discuss this before your appointment - maybe phone the imaging dept and ask their advice?

finty x

I only had MRI in certain areas e.g. Breast and also neck. CT was total body before surgery and I’ve had two since but in specific areas. I’m like you Finty as in hunt the vein! I’m dreading next week as I’m having a Dexa scan. The last bone scan 3 weeks ago was a nightmare as they had five goes at getting a vein. My foot is probably going to have to be used. I asked if the CT could be done without dye and my consultant said yes but it wouldn’t be so good in terms of clarity. Lou x

Hi Finty
When do you know the results of your scan?
Fingers crossed for you


Thanks Ninja & finty, Oh if MRI is that slow i’ll not be comfy with that I would find claustrophobic & probably have a melt down. The CT scan I had in my teens was the whole body & that only took 10 mins then they came it to inject the dye & had another 5 mins LOL Ninja yes all those bits that go HOT I remember well, it was on the way home I felt totally out of it spaced out dizzy & sick this lasted several hours my mum phoned the GP & he said it was the affect of the dye yet there was no warning of this back then & GP said its not that common to get bad SE with it but some do.