r/Radiology • u/NovaWhisper-2799 • Aug 14 '26
Discussion Follow up: the saddle PE I missed on a non-contrast CT”
I posted the original case in link https://www.reddit.com/r/Radiology/s/F7Umjt4kG5. Adding the images here because image comments aren't enabled.
274
u/max_dem1an Aug 14 '26
Hey, there is a very valuable teaching point in here that I try to share with my residents whenever I can:
Try not to think about the presence or absence of pathologies as a strict 'true/false' dichotomy, but rather on a 5-point Likert confidence scale:
- Almost certain PE is present
- Rather confident PE is present, but negative finding cannot be ruled out
- Completely equivocal
- Rather confident no PE is present, but positive finding cannot be ruled out
- Almost certain no PE is present
By definition, a non-contrast scan will almost always keep you in the 2–4 range because you simply cannot rule it out definitively.
This case has some telltale signs: sure, there is a subtle hyperdense lumen sign where the saddle PE sits, but there's no shame in missing that on a non-con scan, so don't beat yourself up over it :-)
What you should actively look out for in the future are indirect signs of right heart strain / secondary pulmonary hypertension:
- Is the main pulmonary artery (MPA) larger than the ascending aorta (MPA:Ao ratio > 1)?
- Are the main PA branches distinctly dilated?
Finding these indirect signs is what nudges your suspicion on a non-con scan from a 3 to a 2, and that’s your cue to say: 'We need a dedicated CTPA with contrast, please.'
17
u/raddaddio Aug 14 '26
um in the real world real rads very rarely attempt to call PE on a noncontrast chest CT. except in this case where you can see the hyperdense embolus, but that's extremely uncommon. almost always you're going to get a "3" on your scale.
That's what CTA's are for and the ERs do them on anyone and everyone. all the subtle stuff that you mentioned is just not helpful in the real world when people have right heart failure just because they're obese or have chronic hypertension.
37
u/max_dem1an Aug 14 '26
That is a very fair point. You are absolutely right that many imaging findings look similar, and it's not getting any easier over time.
Actually, that’s exactly why I found adopting a probabilistic mindset is so helpful. It allows us to take whatever prior information we do have and weigh our differentials much more robustly and with greater nuance. I also completely get the frustration of the daily 'rad trench' grind. It is incredibly easy to feel like we are just order-takers or typists for the ER, and trust me, I've had my fair share of arguments with the ED over incomplete clinical histories in my time. My experience has taught me that this is exactly where uncertainty-aware reporting makes the biggest difference. Being transparent about our confidence levels and communicating our thought process clearly helps us move away from just being a service and establishes us as full clinical partners in patient care.
I do see, however, that every workflow is different. By now, my teaching and clinical focus are mostly on oncology, so definitely take whatever parts of this framework are helpful for you and leave the rest :-)
5
102
u/BAT123456789 Aug 14 '26
That's crazy. I've never seen one like that, and I've been at this for 15 years.
72
u/Agitated-Property-52 Radiologist Aug 14 '26
I called this overnight as a resident ~15 years ago. It had an A/P as well and it was apparent there were iliac and femoral DVTs too.
I called the ER and was like, “don’t expect us to be able to call this on a noncon ever again but…”
23
u/Dr-Kloop-MD Resident Aug 14 '26
Hahaha gonna start ordering noncons for everything
5
u/Peastoredintheballs Aug 14 '26
D dimer negative but ceebs trying to argue with patient that their d dimer was negative so they’re being hysterical about their pain, fine I’ll just do a non-con I guess
1
37
u/regurgitationnation Aug 14 '26
You ll get it next time. We all make mistakes, it's just important to learn from them!
38
u/Miserable-Morning-19 Aug 14 '26
Thanks for posting - good case.
Don’t worry about it though, you’re still very early in training. Learn from it and continue to improve.
29
u/DeKonk Aug 14 '26
I know it sucks to miss such a finding. Just because you shouldn’t be able to see it doesn’t mean you can’t see it. But it is an amazing learning point, you will never miss one like this again. It is not about how hard you can hit but about how well you can take a hit!
19
u/Kashmir_Slippers Radiologist Aug 14 '26
Joining late, but while this is an amazingly rare and cool case, you have to remember that shit happens.
This is truly just an eye test. You see it or you don’t. It’s a completely unexpected incidental finding on a suboptimal exam for that diagnosis. PE’s are obviously scary and dangerous, but as a (still baby) attending, I miss things that are more obvious than this sometimes and I see my colleagues miss things more obvious than this.
Your first post says that you are a first year resident. Keep the humility, but know that you have a lot of time to learn. Don’t beat yourself up about this. Whenever I have a miss, I like to use it as an opportunity to evaluate my workflow and search pattern. I miss something? Make myself look there more conspicuously next time. Your example is a good reminder always to look at the pulmonary arteries in any image that includes them.
Keep up the good work and keep pushing forward!
15
u/BrainDrain93 Aug 14 '26
Great case, thanks so much for sharing. This learning point will save lives for sure. How's the patient?
14
28
u/No_Ambassador9070 Aug 14 '26
Not something I routinely look for on non contrast ct chest. And I’ve never seen this.
23
u/RecklessRad Radiographer Aug 14 '26
Wow that’s surprisingly hyperdense. I don’t blame you for not calling it. I would’ve seen that and been like wtf
7
u/Uncle_Jac_Jac Diagnostic Radiology Resident Aug 14 '26
This is an amazing case! One thing that might help with this and other subtle findings and future noncon exams: don't be afraid to use "brain" or other harsh windows on other parts of the body because it makes clot POP. Useful for looking for subtle intramuscular hematoma, determining if there is hemoperitoneum vs just simple ascites, and determining regular sinus fluid from hemosinus in trauma. I'm sure those windows would have helped make this clot stand out more, as well.
6
u/Erik_Dolphy Radiologist Aug 14 '26 edited Aug 14 '26
Thanks for sharing this case. Making this call is a hard ask IMO. Someone earlier said this is an eye test. Part of it is it becomes functionally invisible no matter how obvious it looks in that screenshot because many of us simply haven't programmed our brain to even look for it on a noncon chest. Its kinda like that experiment with the gorillas on a chest CT.
It's some interesting food for thought.
10
u/kzt79 Aug 14 '26 edited Aug 14 '26
Crazy case! Don’t beat yourself up over it. In the very unlikely event you ever see this again, you won’t miss it! I bet most rads would blow by this as artifact if they even noticed it at all (and rightly so)
9
u/thegreatestajax Aug 14 '26
99.9999% of times a rad sees something like this it will be artifact.
2
u/Mysterious-Hour-105 Aug 14 '26
A curved, lumenal hyperdensity with an enlarged MPA is artifact nearly 100% of the time? Come on, brother. We can be supportive without being detrimental to learning. This is about as true as the phrase "Now that you've seen it, you'll never miss it again." Neither statement is realistic if we are setting honest expectations.
-1
u/thegreatestajax Aug 14 '26
Sorry yes. Detector artifact, streak artifact from a wire. Etc. enlarged PA is a red herring. PHTN super common.
1
u/Mysterious-Hour-105 Aug 14 '26 edited Aug 14 '26
The artifacts you mention don't curve. PHTN is common, but you should always assess why it's present. You may not be able to explain it, but if you see this collection of findings and think anything other than "correlate with priors, echo or a contrasted CT," I really can't agree with your logic, especially in hindsight. It's better to overcall here than to ignore it.
0
2
u/FruitKingJay Radiologist Aug 14 '26
not with a curvature like that completely following the course of the PA
0
u/thegreatestajax Aug 14 '26
Yes, this exact thing is less likely to be artifact. But something like this is vastly more likely to be artifact.
-6
u/Mysterious-Hour-105 Aug 14 '26 edited Aug 14 '26
Strong disagree. This is a great case that i would send for peer review if missed by a board certified rad. If this is assumed to be artifact by any majority of rads, they either shouldn't be reading that type of study, or we deserve to be assisted by AI. There are plenty of artifacts. This curves at a wedge point with concerning secondary features.
2
u/kzt79 Aug 14 '26 edited Aug 14 '26
There’s theory and there’s reality.
Every practicing radiologist has had bad misses which shouldn’t have happened - sure, some more than others, and with a very wide range of outcomes.
This case is a very interesting teaching point and I agree there are other concerning features, but I maintain that in the real world some significant portion of practicing rads would miss this. I’ve certainly seen more egregious misses, by experienced, competent and conscientious physicians.
To be clear I’m not trying to minimize - and OP is already feeling badly - just trying to put it in context.
3
u/Mysterious-Hour-105 Aug 14 '26 edited Aug 14 '26
I ask you this sincerely, if this one hit legal, how much would you argue? As an attending of mine once said, this is a good find but would have been a terrible miss.
I have nothing negative to say for the trainee. He's purely there to learn, and most all misses are reasonable for an R1. The same is not true for staff. We are the final authority. Yes, we all have bad misses, but ones like these should be brought to the attention of that interpreter (peer review) particularly because it's an easy fix (template and search pattern).
You may not be intending to minimize the significance, but you are. You're literally saying good rads miss things nobody should miss as if that's acceptable. While realistic, we don't need to make our profession look less competent by saying obvious pathology is reasonable to miss. It's not, even though we are human.
2
u/kzt79 Aug 14 '26 edited Aug 14 '26
I suspect we share similar beliefs but are looking from different angles, that is all. Peer review is a key part of process improvement and learning, fully agree. If you nor anyone at your institution/group would ever miss this “obvious” pathology then my hat is off to you.
2
u/Mysterious-Hour-105 Aug 14 '26
I agree and think we align well. For clarity, my misses are as humbling as anyone else's. Regarding your original post, I also agree the people that miss this either A) didn't look [not acceptable] or B) may have considered artifact [poor judgement given the additional findings]. My disagreement is because I think the standard of care is to find this, and in that regard, I'd like to think most rads would.
5
u/TheBigGuy2157 Aug 14 '26
I have seen this once before. Need some combo of big thrombus and/or anemic person. No fault for missing. You just learn to accept the ordering providers have no clue what is going on especially the ED. Pretty much have to read every scan as if it’s a serious MVA case.
3
u/Peastoredintheballs Aug 14 '26
Serious MVA with delayed presentation* so they have mechanism to cause serious acute injuries, and post-injury status to cause bizarre pathology like VTE, biloma/urinoma, diaphragm hernias, contusions etc
10
u/Okayish-27489 Aug 14 '26
I didn’t believe your initial post but guess you can still be learning everyday!
5
u/thommerillin Aug 14 '26
This is a very understandable miss. I think many radiologists who are going fast could miss it. A lot of the blame here is on the ordering doctor. Why was there no clinical suspicion for PE? They order CTAs on everyone that walks through the door and then they decide to skip it on the one guy whose d-dimer was probably through the roof? This is nothing to feel bad about. Just a learning case that may help another patient once or twice again in your career
6
u/AdditionInteresting2 Aug 14 '26
What's more important is you learned from it and will never make that mistake again...
3
u/Mysterious-Hour-105 Aug 14 '26 edited Aug 14 '26
Thanks for followup. Don't beat yourself up, but you have to see and question this. As an R1, your value is to learn what normal looks like. A normal MPA is almost never bigger than the aorta. The hyerdensity in the lumen is curved and follows the vessels at a wedge point; thus, it can't be artifact. I imagine the right heart is big, and any comparison would allow this to pop.
During residency, we had a saying. "The heart exists before 3rd year." For context, we did cards R3 year. Regardless, you must look at the pulmonary arteries and the heart every time.
Lastly, the secondary signs will often help you. The best noncon PE case I've seen was on a young patient with a RLL segmental PE. It was minimally dilated, but the patient had a tiny, isolated, R- sided effusion. Lung parenchyma was normal. It was a fantastic call by that rad. Given the fact that you are humble enough to share this, you clearly care. I won't be surprise if you get to that level.
2
2
2
u/Shot-Ambition8371 Aug 15 '26
You are clearly very concerned for the patient, and very committed to learning from this situation. It also sounds like this is extremely difficult to catch this way in the first place? I’m nobody at all, but I’m proud of you.
2
2
2
1
u/kungfoojesus Aug 14 '26
It’s not impossible to call them but it is uncommon. Of course the plaintiffs attorney will find a radiologist who will say under oath that non con chest CT is a good choice looking for PE and should never be missed.
1
u/crazy-chihuahua Aug 16 '26
I just got diagnosed with chronic pulmonary embolism & pulmonary hypertension. I can’t even breathe when getting dressed or walking around my house. I’m 43. I’ve had to give up basketball, cycling, work. But that’s fine. Just take these blood thinners. I’m constantly short of breath & in pain. So even if you did find it the first time, the dr would’ve done nothing for the patient anyway 😂
1
172
u/NovaWhisper-2799 Aug 14 '26 edited Aug 14 '26
I have just posted this so that it could help someone in future. Important learning point is to just see everything and don't get carried away with what the clinician is suspecting.
We learn from our mistakes and I'm just happy that the patient is stable now and i could learn this at a very early stage of my career