03 October 2008

Something you don't see every day

We had a trauma patient recently who was in her third trimester of pregnancy.

It was a bad trauma: motorcycle-related with multisystem injuries and a frankly unstable patient. We knew she was pregnant but had an urgent need for definitive imaging, so the decision was made to obtain a CT scan. Here are the rather uncommon images:

This is a transverse image through the mid-uterus. Clearly visible is the bony skull, midface, hands forearms and legs of the fetus. I may be incorrect (any radiologists out there?) but I believe there is a small amount of fluid, probably blood, in the right paracolic gutter.

Our hospital has been doing gee-whiz coronal reconstructions routinely on scans, and this one is even more gripping. You can see the baby in near-perfect profile:
Again, fluid is visible in the right lower quadrant.

Trauma in pregnancy is complicated with regard to imaging. You need to try to minimize the amount of radiation while not compromising the care of the patient. Ultrasound is a good screening tool (especially for the well-being of the fetus), but does not provide great detail for the solid organs and viscera, nor for the retroperitoneum. Pelvic fractures (which this patient had, but are not visible on these images) and their concomitant injuries are essentially only visible on CT. But the radiation dose is somewhere around 500 mRem, or about 50 times the chest x-ray dose, with the radiation focused on the fetus. So there's a complex risk-benefit calculation you need to do before ordering the test. In this case, the fact that the baby was more than 20 weeks gave us a bit more latitude -- the risks of radiation are highest in the first twelve weeks, when the organs are being formed.

For stable patients, I have seen abdominal MRI utilized, which has the advantage of not irradiating the embryo, but the disadvantage of being time-consuming, difficult to obtain, and requiring the patient to be stable enough to sequester in the tube for the scan. I don't know whether there is any diagnostic advantage to CT or MR in trauma; almost all our experience is with CT, but I would imagine that the MR images are sensitive for most injuries, possibly moreso than CT for some.

I wish I could say there was a happy outcome to this case. Unfortunately, both mother and baby expired due to reasons unrelated to the findings on these images. As I said, it was a bad trauma and we knew from the moment the patient arrived that the odds were poor. A peri-mortem C-section was not an option, as the fetus expired first. I felt, however, that these scans were of sufficient educational interest to be worth posting, as they are quite unusual and they touch on an interesting management conundrum.

Thankfully, this is not a dilemma we ahve to wrestle with too often.

11 comments:

  1. You're right. We don't see this often. In fact, I've never seen one in 10 years of radiology. Great images.
    Those were the bones of the forearms and legs in the first image.
    Bad that both didn't make it. Was she in shock? The thickened small bowel loops - in the left flank on the second image - look like shock bowel.
    PS. Word verification was cmdleg !!

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  2. Vijay,

    Thanks. She had other injuries that more proximately caused her death (most prominently a head injury). But she had a belly whack for sure.

    BTW, what's the significance of cmdleg?

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  3. No big significance other that it sounds - see MD, leg! (the bones in image 1)

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  4. Sad story, but beautiful images. I guess they don't do routine 3d reconstructions of those ct images yet??

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  5. Not routinely. We can get them, but most typically I see them for CT-angio

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  6. Those are amazing pictures. Thank you for showing them. Granted, I have very limited experience, but I've never seen anything remotely close to that.

    Yeah we only do 3d recons for angio, IVPs, and mandibles.

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  7. Wow, that's an amazing image. Sad about the patient and her baby though. :(

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  8. Wow those are amazing. Tragic outcome, but obviously everything was done.

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  9. Am I the only one who thought: "wait - 'motorcycle-related' and 'third trimester'?!" I've never been pregnant, but I do ride a motorcycle, and that just seems like such an obviously bad combination.

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  10. You aren't the only one to think "Why was it a motorcycle accident?". I'm hoping the pt. had more common sense than that, and it was motorcycle vs. ped.

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  11. guys doing that kind of coronal recon itself causes thin slices 2 be taken.won't it cause heavy radiation .
    by the way what were the thickness of the slice.

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