Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: Karen W. on 13/12/2008 10:46:40

Title: How precise are Cat Scans using the iodine, at determining sizes of Aneurysms?
Post by: Karen W. on 13/12/2008 10:46:40

Well I am scheduled to go in Tuesday for yet another scan... There is reason for me to believe that the two I have, have grown more then had been anticipated...

I am curious as to how precise measuring an aneurysm is with an iodized cat scan? Is it all down to the radiologist technicians skills or what?

Does the machine itself take the measurements etc..?

Waiting on pins and needles.. for your speedy replies... LOL Thanks!

Title: Re: How precise are Cat Scans using the iodine, at determining sizes of Aneurysms?
Post by: RD on 13/12/2008 11:10:37

I think that measurements made with a typical medical CT scan would have millimeter accuracy.

www.sciencedirect.com (http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T11-4BVJS6V-F&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=b12d7bc6fe75c7d59cb1858fc4e908ac)

Title: Re: How precise are Cat Scans using the iodine, at determining sizes of Aneurysms?
Post by: Karen W. on 13/12/2008 11:25:15

Thanks RD I read the link but could you tell me in laymans terms what that meant?

 Seems for the most part good results but still limited.. 

Title: Re: How precise are Cat Scans using the iodine, at determining sizes of Aneurysms?
Post by: RD on 13/12/2008 12:06:24

The example I linked to was a 2003 CT scanner which had a sensors 0.5mm apart.
So measurements parallel to the sensor array would be accurate to the nearest 0.5mm. 
If the measurements were diagonal (45^o) to the 0.5mm sensor array the accuracy would only be to the nearest 0.7mm (Pythagoras).

So the CT measurements would always be within one millimeter of the true distance.

No measurement is perfectly accurate: all measurements are within a known margin of error.
Measurements do not have to be perfect to be useful, they just have to be accurate enough for the particular job.

Title: Re: How precise are Cat Scans using the iodine, at determining sizes of Aneurysms?
Post by: Karen W. on 16/12/2008 07:45:52

Thank you RD for taking the time to explain that better.. I understand now.. Thanks.. Going tomorrow mid day...drinking tons of water and my blood tests Last week for my Kidneys look good this time.. So This time I do not have to take that nasty Mucomist stuff! YAYYYYYYYYY! Just drink Tons of water before and after... She said this was the best kidney test I have had in a long time so I hope this Iodized junk doesn't screw it up again!

Title: Re: How precise are Cat Scans using the iodine, at determining sizes of Aneurysms?
Post by: Bored chemist on 16/12/2008 22:01:34

OK, I know it's only me who's worried, but please could somemone put the hyphen in the title.
I keep wondering who is iodizing cats and why anyone would like to scan them.