These days, the diagnosis of pulmonary embolism
is almost always made by a CT angiogram in
which we actually see contrast arriving in
the artery and showing that there’s a defect
where the clot is.
This is actually a contrast pulmonary angiogram
where a catheter is inserted and squirts the
dye in. But in fact these days the CT scans
are so accurate that we can just administer
the dye intravenously, do the CT scan, see
it when it arrives in the lung bed and pick
up the pulmonary embolism. This test has now
essentially replaced the lung scan except
in patients who are allergic to the angiographic
dye. Those patients may still get a lung scan
and we accept in the clinical setting that
the lung scan is not as accurate as the CT
The CT angiogram is high accuracy in the case
where we put a catheter in. It’s an invasive
test so there’s a chance for complications
of the invasive test. But with the CT angiogram,
it’s mostly a non-invasive test, just with
some intravenous injection of the dye.
And here you see a very nice picture showing
a beautiful clot in the inferior interlobar
branch of the left pulmonary artery.
You can also do an angiography by MRI. Here
you see an MRI angiogram and, again, the green
arrow points out a clot in this MRI angiogram.
By the way, you can also see the aorta and
the brachiocephalic artery and the left subclavian
and the left carotid artery as well.
You can see how beautifully visualised the
arteries are with this MRI. And the CT angiogram
gives you a similar picture. Very, very excellent
picture, both non-invasive.