CT Scan of the Chest Explained Clearly – High Resolution CT Scan (HRCT)


welcome to another MedCram lecture I
want to give you a little bit of insight on CT scans of the chest and this kind
of 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 nodular
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

26 thoughts on “CT Scan of the Chest Explained Clearly – High Resolution CT Scan (HRCT)

  1. so what about an pulmonary embolism high resolution with contrast or simple ct with contrast
    Thank you

  2. P.E. needs a CT scan with contrast that can be done within 20 sec and taken while the contrast is in the pulmonary circulation. (not HRCT)

  3. Very informative. Over the weekend my doctor called advice me two of the test he did were not normal xray or ekg. N he breeder to do a ct scan. What do you suppose that means?

  4. very helpful on the difference on tests, for I have had on of those and now I know which one I had and why and what they may or may HAVE NOT found. Thank you

  5. Great video with clear explanation. Can you also explain the use of prone images for HRCT protocols? I used to work in CT a few years ago and noticed the protocol has changed. We used to employ a large slice gap in the upper chest as this is less likely to be affected by the types of diseases investigated and lowers the radiation dose. A much thinner gap was used in the lower region of the chest. Now protocols include the whole chest. Do you know the reason for the change? Is that because we have more advanced techniques to lower dose?

  6. great video would you be able to do some more CT related videos please explaining other types of scans as well as contrast enhanced scans?

  7. I just had a CT scan they were looking for a blood clot in my rt lung how accurate are they in finding them 80% 90% ? thanks great video

  8. Do ct scans use radiation? Can u tell me why my doctor did zero tests on me and just assumed i have asthma and just gave me inhalers without any tests?????? I am not a student i am a patient concerned about my lung health and i am wondering about what all these lung tests test for and are they safe and do they use radiation that could make issues worse

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