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s1artibartfast 4 days ago

not a doctor, but a CT could show mechanical obstruction or twisted intestines in a way X-ray would not.

I imagine the doctor already assumed the shit was there, but wanted to understand why.

I further imagine prescribing a megadose of laxative might be harmful if someone cant expel the shit.

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bobmcnamara 4 days ago | parent [-]

I really wonder if there's value in straightening the tract in post. Sometimes something at 45 degrees doesn't really view well in the slices.

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s1artibartfast 4 days ago | parent [-]

CT isnt constrained to 90 degree slices and can be viewed at any arbitrary angle, or in 3D without further processing.

This video [1] is a presentation on bowel CT with great images. For those interested in X-ray, compare the X-rays at 14 minutes with the CT at 10.

Also worth noting, that X-ray is being recommended as a quick diagnostic before moving to CT

https://youtu.be/ZvDOkrn2ygQ?t=630

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bobmcnamara 3 days ago | parent [-]

I knew the math wasn't limited to 90 degree slices. I've had a few CT scans, and twice when I got my copy the DICOMs were a bunch of 90 degree TIFF slices. It wouldn't surprise me if the radiologist had the raw beam data and could slice it however they chose.

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s1artibartfast 3 days ago | parent [-]

the Tiff slices is just post process storage. A good DICOM reader can view those tiffs in any direction.

After all, if you have the tiffs, you already know the grayscale for every pixel in the XYZ space. You just need to grab the right pixels from each slice

	▲	bobmcnamara 2 days ago \| parent [-]
		Interesting stuff! Could you suggest a DICOM reader that does so? I had assumed slicing the raw beam data would give you much better output resolution whenever there were differences between transaxial and z resolution, since at some angle and offset you end up sampling across the largest gaps in the XYZ pixels. But maybe that's not a real issue? Is this how it's done in practice?