Interactive Transcript
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Applying the knowledge that you
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learned, let's analyze this case.
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This case was a patient who had
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pain, belly pain and chest pain.
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So they did a CT angiogram of the
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chest to look for aortic pathology.
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And they also did a routine belly
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to look for an acute abdomen.
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This is an image from the routine belly.
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And this is an image from the
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CT angiogram of the chest.
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So what do you think?
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went wrong here.
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Take a look at the images.
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Here's what I asked the tech.
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I said, I asked the tech, where did you trigger from?
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And he sent me those trigger images.
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And these are the images that they sent me.
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So what was the issue?
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We have a few options.
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Region of interest was placed in the false lumen.
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Patient had low cardiac output.
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Tech was incompetent and the patient moved.
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The answer is low cardiac output.
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Be very careful in blaming the tech because
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it's often factors that are very technical.
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Patient moving is always a problem, but
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the region of interest didn't show that.
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And yes, the ROI could have been in
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the false lumen, but the problem wasn't
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that the ROI was in the false lumen.
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If the ROI is in the false lumen, the scan starts late.
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Here, the scan started early.
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See the chest scan started early.
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I mean, in a sense, it didn't start early.
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It started early only in relation to
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the contrast because see that the
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pulmonary artery is nicely pacified.
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Aorta is not touched.
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When we do the routine belly, which was done with
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a 70-second delay from the time of injection,
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you have almost perfect arterial pacification.
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So the issue was low cardiac output.
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This patient actually had a type A dissection,
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which also led to a myocardial infarction,
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which also led to a low cardiac output, which
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is responsible for the problem that we see.
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Okay, so let's.
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Continue applying principles, and although
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this is not cardiac, I think, um, we should
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think of the principles that we've learned.
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To evaluate distal renal arteries for medium
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vessel vasculitis, we must increase contrast
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volume, increase injection rate, use saline
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bolus, lower KVP, and all of the above.
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So, what am I asking?
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I'm asking if you have a protocol that you've set
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up for a CT angiogram and you want to now vary that
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protocol to look for medium vessel vasculitis
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in the renal arteries, which has second-order
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arteries, that you want to look for abnormalities.
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What are you going to do differently?
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And the answer is you're going to do all of the above.
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You're going to increase the contrast volume.
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Because by increasing the contrast volume, you're
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going to increase the peak maximum enhancement
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and also the plateau along which it would apply.
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You'll increase the injection rate, which
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will reduce the time to peak, whilst
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also increasing the peak maximum enhancement.
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The saline bolus will tighten the
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bolus and push things together.
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Lower KVP will give you more iodinated bang for
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your buck, so you would do all of the above.
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