CTV experience - UK

I wanted to write a quick post on my experience on having a CTV performed today in case anyone is having one soon or in the future and wants to get an idea of what its like, how it feels and also the costs involved. I’ve written this from the perspective of someone who wants every detail.

My CTV was ordered by Mr Jake Timothy and performed at London Bridge Hospital. I had to fast (not eat) for 2 h prior to my appointment time, so if this is an issue would consider an early appt. Mine was at midday so i was ok. I presented to the relevant people, had to check in etc and then head to the radiology part of the building. They like you to arrive at least 15 mins before to do this.

I then had to fill in a basic healthcare questionnare, nothing too onerous but just to elicit whether you may have a reaction to the contrast medium (more on that later).

Once at the radiology department I was called to change into a gown. I was allowed to keep my trousers and shoes on but as i was having my brain and neck scanned, i had to take off my t-shirt, glasses, watch (basically anything above the belly button. I was then instructed to sit in another waiting area, where they then took me to the scan room.

There were 3 people in the room, one who did most of the set up. First they had me lie down in the CT scanner which is basically just a narrow bed and a circular machine which is around the bed at the head (google CT scanner if you need more detail). They then put a cannula in my arm, which they used to take a bit of blood to check my creatinine and EGFR levels (aka my kidney function) as this is important for clearing the contrast medium. The cannula insertion hurt a small amount but really, if you have neurological symptoms or vascular - its nothing on that - but just imagine a blood test. They then tested the flow of the cannula by injecting a small amount of saline which gave me a nice salty taste in my mouth and smelt like i was by the sea :slight_smile:

Ok so now its show time! They connected my cannula up to the automatic infuser as they have to leave the room otherwise they would be exposed to the X-rays (and when you do that kind of job you cant have that every day!). They started the machine and the automated bed moved me partially under the ring. The machine makes a fairly loud noise because inside there is a ring which rotates fairly fast.

The techs/radiographers then leave the room and go behind a glass screen where they tell you they are about to start the infusion of the iodine contrast agent which enables them to see your blood vessels. Now this is where things start to get fun, once the iodine is infused you basically get a very warm sensation through your body starting from the arm that your cannula is in, then your heart, trunk, feet, and basically the entire body starts to feel warm - almost like wetting yourself when it hits your kidneys. That sensation for me lasted about 1-2 mins. Then it was over, they took me out, where they instructed me to drink lots of water to flush out the iodine.

Then i got myself changed back out of the gown and headed out - i personally am self pay (as it was private) so went to the desk to get the invoice and just decided to pay there and then.

Then i left, had a nice mcdonalds and went home! Only mild lasting effects were a strange head sensation ( but i have a 24/7 headache) so didnt really notice anyway!

If anyone is interested - the reason why they inject iodine is because it is a heavily X-ray absorbing element (because it has a lot of electrons compared to the hydrogen, nitrogen, oxygen and phosphorus our body is typically made from ) - PhD in Chemistry coming useful here.

Hope this helps and happy to answer any further questions if anyone has any.

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I’ve always been wondering, what the mechanism is behind feeling that “salty” (in my case, more like burning “alcohol”) sensation and smell (?) after saline injection. Perhaps it’s going through lungs then with the exhaled air reaches the smell receptors?..

Also, any thoughts on why the iodine contrast has such a burning/unpleasant sensation as soon as it is injected? Temperature differences (blood is warm) might be one explanation, but e.g. simple IV drip with saline doesn’t cause it (in my case) even though the temperature difference is the same. Perhaps something to do with the blood vessel inner lining (temporary) damage?..

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@vdm - So i think the salty taste may be due to some osmosis in the taste/smell sensors . If you increase the ionic strength of blood even slightly, your cells will shrink, where they release water and perhaps there is some sensory effect which makes this feel salty. All speculation, no evidence, but i’m just thinking that saline in principle is isotonic (same ionic strength as blood), i think with small changes like how much water you’ve drunk that day will have an effect.

So its clearly not the injection itself, as you said said simple fluids IV it doesnt occur. I had a quick look and apparently iodine is a vasodilator (which maybe makes me question whether its a good thing to assess stenosis…). So more blood volume i guess has a heat transfer effect, more blood to vessel lining surface area which for sure will make you feel warm. Cant be sure again but could be a mechanism!

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Quick thing to add - i just pulled the plaster/bandage off from the cannula insertion site. That was the most uncomfortable painful thing i have done all day… why did they have to put it on my arm hair :sweat_smile:

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@LimeZest that actually makes sense. Also I just checked about iodine contrast effects, it seems there are additional issues affecting the lymphocytes. Maybe the body recognises that and starts eliminating the affected cells promptly, temporarily disrupting the “normal” balance of blood consistency. Just a wild non-educated guess.

https://www.sciencedirect.com/science/article/pii/S0720048X17301493

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@vdm certainly a possibility. Am always wary of these types of in vitro experiments, it does corroborate with other in vivo (mouse) and human data but quite a difference irradiating some cultured lymphocytes compared to an animal. But ultimately any cells which have taken up the iodine may have some effects. At the end of the day, the energy used to irradiate during a CT scan is absorbed by iodine - which has to go somewhere probably released as a photon in a non-visible wavelength (this is commonly known as X-ray fluorescence). Perhaps the lower energy photo that is emitted can invoke some other form of damage. I dont think this is the mechanism for the warm feeling, but definitely interesting research here that CT + iodine may be more damaging that CT on its own due to some synergistic effect

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I’ve had a couple of CT scans w/ contrast over the years & never noticed the “salty” taste or smell, but that may be because I lost much of my sense of smell (& thus taste) after my cycling accident/head injury in 2015. I’ve since learned that head injuries can cause loss of those senses. I guess it depends on what part of the brain is damaged.

Before my last CT w/ contrast I was warned ahead of time about the upcoming sensation of having wet myself. Fortunately it was only a sensation not a reality! :joy:

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