CT Myelogram versus Spinal Tap - Dangerous for Chiarians?


I have heard that spinal taps are dangerous for Chiarians. A spinal tap (in which 4 vials of fluid were removed from me for study) this past year is what set off pain for me that has been at times excruciating and has never stopped. I have been told I have a slow CSF leak that has never stopped (they tried a blood patch to stop it but it did not work - it may have even ripped the dura farther and created a worse leak.) My head pain has gotten significantly worse.

I know that a CT Myelogram is commonly done to study CSF flow, which is again a puncture of the dura.

How does a CT Myelogram differ from a spinal tap, and if a spinal tap is dangerous, how is a CT Myelogram not dangerous, for a Chiarian?

I am frightened of ever having more needles through my dura, lest my leaking and pain become worse! Does it make a difference, that in the CT Myelogram, something is being put IN rather than taken OUT, as in the spinal tap? This may make the difference, and may be the reason it is safe for a Chiarian.

Can anyone shed light on this? Thank you so much!