SPECT scan did not show CSF leak. Should I do CT abdomen?

Hello,

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I cannot but appreciate what you call your "curiosity". I would rather call it your awareness and consciousness. One should indeed think twice before going through a radiation exposure for a second time. If I say in one word, the CT scan your doctor has recommended is required if the adrenals are to be visualised. Let me explain and elaborate. Firstly, please note that SPECT and CT are two entirely different imaging technologies (despite the same surname "CT"). When you had the SPECT, the dye was injected into the central canal, i.e. the CSF cavity of the spine. That way, the dye could reach wherever CSF could reach, so that it could be identified whether CSF was leaking out of its normal boundaries. The dye did not obviously reach the adrenals and so they were not visualised.

However, SPECT is usually done in combination with CT (called SPECT-CT). In that case, the adrenals were visualised by the CT component of the scan. Still, this visualization is not sufficient for the adrenals for two reasons. One is that they are very small, so adrenal imaging requires "thin" sections. Secondly, evaluation of adrenal pathology often involves determining the degree of contrast (aka dye) uptake and washout at specific time intervals. These intervals are programmed into the CT machine under "adrenal protocol".

Your urge to avoid another radiation exposure is reasonable and appreciable. Ultrasound and adrenal protocol MRI may be alternative choices that are free from this risk. However, their applicability in adrenals is quite limited as compared to CT. You may still discuss with your doctor(s) whether ultrasound or MRI may provide the answers they are looking for. So, in conclusion, the adrenals were not visualised in SPECT, and CT is the best way for evaluation of adrenal pathology.