CT Cisternography

 CT Cisternography is a specialized imaging procedure used primarily to evaluate cerebrospinal fluid (CSF) leaks, CSF dynamics, and arachnoid cysts. It combines a lumbar puncture (for contrast injection into the subarachnoid space) with CT imaging of the brain or spine.

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🔍 Indications

• Suspected CSF rhinorrhea or otorrhea

• Evaluation of skull base fractures

• Assessment of arachnoid cysts

• Pre-surgical mapping of CSF pathways

• Detection of normal pressure hydrocephalus (NPH)

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🧪 Procedure Overview

1. Preparation:

   • Patient consent

   • Check for contraindications (e.g., elevated ICP, bleeding disorders)

   • Local anesthesia and lumbar puncture

2. Contrast Injection:

   • Intrathecal injection of iodinated, non-ionic contrast via lumbar puncture (typically at L3-L4)

   • Patient is then positioned head-down (Trendelenburg) to allow contrast to move cranially

3. CT Imaging:

   • Images taken at intervals (commonly 1–6 hours after injection)

   • Target area: skull base, brain, or spine

   • Thin slices and multiplanar reconstructions for accurate leak localization

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⚠️ Risks and Complications

• Headache (especially post-lumbar puncture headache)

• Infection

• Bleeding

• Allergic reaction to contrast

• Seizure (very rare)

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🧠 Key Points

• Highly sensitive in detecting active CSF leaks

• Often used when MR cisternography is inconclusive

• Dynamic CT cisternography can detect intermittent leaks