High Resolution CT Scan (HRCT) Explained Clearly – Remastered
22
August

By Adem Lewis / in , , , , , , , , , , , , , , , , , , , , /


welcome to another MedCram
lecture I want to give you a little bit of insight on CT scans of the chest and
this brings up a point about high resolution versus just a regular CT scan
of the chest when do you order one versus the other
let’s talk about that so if there was only one type of CT scan that you could
get and you were concerned that you had a lung nodule what kind of CT scan would
you get would you get a regular CT scan or would you get a high-resolution CT
scan let’s talk about those two types of scans now let’s pretend this is your
lung kind of looks like a pacman ghosts but nonetheless and here’s our little
nodule right here in the lung and you’ve got a choice you can do a regular CT
scan or we can do a high-res CT scan otherwise known as an h r CT okay so
which one is gonna be the best way to go well first of all we got to know about
how they do these things so a regular CT scan basically does slices just like all
CT scans do and they put it up onto the screen so there’s basically what they do
but regular CT scans do something specifically as they take all of the
data between those scans okay so all this data here gets plastered onto that
film and all of this information gets plastered onto this film all of this
information gets plastered onto that film and so forth and so forth and so
what you get is something called volume averaging where you take the average
signal in that entire space there and that image gets put onto that screen
that you’re seeing okay and so the point here is
that every square millimeter of the lung is imaged in some way and has some sort
of representation on the film below it now that’s different than a
high-resolution CT scan here you still get cuts okay but these cuts don’t volume average
you’re actually getting the image from that area and all of the space in
between those cuts are never really imaged and so what’s the advantage of
doing this the advantage of doing this is you get a very very detailed look at
the architecture of that slice of the lung so here we’re looking for
architecture so if I’m looking for what am I looking for here I’m looking for
fibrosis I’m looking for emphysema I’m looking for bronchiectasis I’m not
looking for nodules if I were looking for nodules I would want to go over here
and what’s the reason I just sort of demonstrated that here you could
theoretically have a nodule in between those two slices and completely miss it
if it were small enough to fit in between the distance between these
slices because you’re getting a high-resolution image whereas here
everything gets volume average so it’s not gonna be as clear it’s not gonna be
as distinct but you will pick up everything here it will be distinct but
you may miss stuff you will miss stuff in between so when do you order one
versus the other I would order a regular CT scan if you’re looking for nodules or
if you want to follow the size of nodules to see if they’re growing if on
the other hand you’re looking for architecture for instance you’re looking
for emphysema you’re looking for fibrosis you’re looking for
bronchiectasis you’re looking for ground glass of pacification you’re looking for
a specific way something might look in terms of an infection or micro nodule or
pattern then you need to get a high-resolution CT scan usually this is
done without contrast okay so now you know how to order your CT scans thanks
for joining us you


9 thoughts on “High Resolution CT Scan (HRCT) Explained Clearly – Remastered

  1. Thank you, great video and explanation. To add, HRCT are done prone sometimes as opposed to conventional CT chest which would always be supine. Prone position lets the heart fall anterior in the chest allowing more lung tissue to be imaged.

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