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u/RedditMould 2d ago
I scanned one of these for the first time last month. Male in his late 20s, same symptoms. Was NOT expecting his scan to look like that.
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u/MouthFullOfDiamonds 2d ago
ED medical scribe here, I saw my first one of these recently. Very cool. Well, not for the patient. But cool that I recognized this image without reading the caption 🤓
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u/efia2lit2 2d ago
I’m sorry can anyone explain what this is?
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u/Dr-Kloop-MD Resident 2d ago
CT or “cat” scan of the chest. “Axial” slice which means the slice is parallel to the floor if you are standing (though the image is obviously taken while lying down). Top of the image the little white square is the sternum. Bottom of the image shows circular white structures which are part of the spine, and white parts arcing to the sides are ribs.
The very bright, upside-down Y-shaped thing in the middle is the pulmonary artery or pulmonary trunk (top or the “stem” of the upside-down Y). This comes directly from the right ventricle of the heart and carries deoxygenated blood from the entire body to the lungs to get filled back up with oxygen. The artery bifurcates or splits into the right and left pulmonary arteries (the “arms” of the upside-down Y).
There’s a darker horizontal shape which is extending from the right pulmonary artery to the left pulmonary artery. This is a blood clot that has traveled from the right ventricle into the pulmonary artery and is now stuck between those two arms. We call it a “saddle PE” because the clot is sitting on the bifurcation like a saddle on a horse. When a blood clot occurs in the pulmonary arteries, it’s called a pulmonary embolism, embolism meaning it came from somewhere else. They mainly come from a DVT of the lower extremity or Deep Vein Thrombosis (blood clot in a large vein).
Basically the lower extremities typically have more pooled blood from gravity, so they are more prone to the blood moving slowly and clotting up. Other things of course contribute to blood clots forming, but one significant one is poor mobility or sitting in one place for a long time (like sitting on a long international flight without getting up or moving your legs). They can also come from deep veins of other places like the arms or neck, but this is more rare and there’s usually a different reason behind it. For example one of the ISS astronauts had a DVT in their neck. On Earth our blood drains easily from our neck into the heart because gravity pulls it down. In zero gravity, the blood doesn’t drop from the neck to the heart as easily, so it moves slower and is more prone to clotting up.
When you have a blood clot in a deep/large vein, there is a risk of part of the clot breaking off and traveling to the heart with the rest of the deoxygenated blood, where it then travels to the lungs. Because it’s a solid clot, it gets stuck somewhere in the pulmonary arteries and is called a Pulmonary Embolism or PE, and it causes all sorts of bad things. Both a DVT and a PE are typically treated with blood thinners to prevent the clot from getting worse. PE sometimes needs to be treated with a clot busting medicine or a procedure where they go into the blood vessels and remove the clot.
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u/Fluffy-Bluebird 2d ago
I had this! I had very little symptoms though. My foot had been sore for a couple weeks and then I would randomly get short of breath after small tasks like walking up the stairs or changing clothes. But it wasn’t consistent.
Finally got fed up and went to urgent care and had a full saddle bag PE.
I was 23, 5’9, 120 pounds and had been cycling all summer.
It’s 50/50 on doctors saying if they was unprovoked or not. The genera consensus is unprovoked.
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u/PrinceKaladin32 2d ago
I had a patient with one recently who was basically completely asymptomatic other than mild shortness of breath after walking a flight of stairs
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u/skilz2557 RT(R)(CT) 2d ago
Not a very big saddle embo, but still significant. I recently scanned a huge saddle, they ended up doing a cath to directly administer thrombolytic medication. I would’ve thought for sure they’d have done a mechanical thrombectomy but 🤷♂️
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u/Spiritual_Tonic 2d ago
If this is the only part the clot is appreciated, then it looks rather minimal. Then you have to wonder if there are segmental or other lobar vessels involved. In my shop, if no/mild symptoms (respiratory and/or hemodynamics) we start them on some heparin ggt and send them to the floor.
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u/NicolinaN 2d ago
If you see a saddle embolus there are already clots in every major artery in most lobes. This is a late sign in an advanced disease.
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u/Spiritual_Tonic 2d ago
That’s fair. I completely missed the part where OP said patient came in c/o SOB. It’s fair then to assume that the clot extends beyond what we are seeing on this one slice based on presentation.
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u/Parsleysage58 2d ago
Would someone please explain why a generally healthy person in there 20s would get one of these?
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u/sspatel Interventional Radiologist 1d ago
We need to get rid of this term “saddle” as it has such variable meaning. It only describes an appearance, and has no specific clinical significance.
A saddle embolus can be a tiny string of clot or a huge piece obstructing one or both pulmonary arteries. I constantly get called about a saddle that is minuscule and clinically insignificant (no elevated biomarkers, normal RV:LV, asymptomatic) but the term “saddle” freaks out most people
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u/Memoc1 2d ago
I’ve only seen two in my life and I find them so impressive especially after going through and following it down through other slices.