CT cisternography

Combination of images from a CT cisternography study of the head

Similar expressions

CT cisternography/ CECT cisternogram

Introduction

CT Cisternogram is a contrast study used to diagnose abnormal cerebrospinal fluid (CSF) leaks-mainly into areas such as paranasal sinuses, nasal cavity (CSF rhinorrhea), middle ear cavity (CSF otorrhea), subarachnoid space and mastoid air cells.

Patient preparation

  • Remove hair clips, ear rings or any removable metal in the exposing area.
  • Explain the procedure clearly.
  • Prepare the patient for contrast administration and lumbar puncture.

Contrast administration:

  • Fluoroscopy guided lumbar puncture is performed by a Radiologist.
  • Iodinated contrast media is administered into the thecal sac.
  • Table is tilted to make the patient’s head down.

Explanation: this position helps to move contrast media towards the head.

  • Patient is transferred to the CT room after a successful lumbar puncture and contrast  administration.

Patient positioning

Patient positioning may change according to the condition of the patient.

  • Head-first-prone position is suitable if the patient is leaking CSF from the nasal cavity (CSF rhinorrhea).

Explanation: position the patient to promote active leakage of CSF (slight elevation of the pelvic area), sneezing can also be an action to promote CSF leakage.

Images of a CT cisternography demonstrate abnormal CSF flow paths of a patients sinuses.
  • Center the scanning area in the scanner iso-center [2].

Explanation: this reduces overall radiation exposure and increases image quality.

  • Radio-lucent pad can be kept under the forehead to make room between the table surface and face.

Scan planning

Non-contrast CT head may help to identify contrast leaking areas in comparison with thepost-contrast images.

Demonstrates scan slab planning for CT cisternography study.
  • Plan the scan starting point at the angle of the mandible (patient in prone and head first position).
  • Plan the scan slab to cover from the skull vertex to mandible.

Post-processing

  • Axial, sagittal and coronal images in bone (WW:4500, WL: 450) and soft-tissue (WW:400, WL: 40)   windows, with slice thickness lower than 2mm.

Explanation: these images should clearly demonstrate CSF leaks.

Please refer to our Brain contrast and Sinus article for MPR planning and images.

Reference

  1. Amrhein, T. J., Goldman-Yassen, Adam MD, & Ali, Saad MD. (2024). ACR–ASNR–SPR Practiceparameter for the performance of myelography and cisternography. Retrieved from gravitas.acr.org
  2. Romanyukha, A., Nzitunga, P. S., & Dolcet, A. (2022, April 28). CT patient positioning plays key role in radiation dose reduction. www.auntminnie.com.
  3. Hablas, L.T., Ammar, A.M. & Elnagar, R.M. CSF rhinorrhea: non-contrast CT, contrast-enhanced CT cisternography or combined?. Egypt J Radiol Nucl Med 53, 201 (2022).
  4. Shetty PG, Shroff MM, Sahani DV, Kirtane MV. Evaluation of high-resolution CT and MR cisternography in the diagnosis of cerebrospinal fluid fistula. AJNR Am J Neuroradiol. 1998 Apr;19(4):633-9. PMID: 9576647; PMCID: PMC8337403.
  5. Rahalkar, Mukund & Rahalkar, Anand & Joshi, Vardhan & Sant, Kailash & Zade, Kourabhi. (2017). Computed Tomography Cisternography for the Management of Cerebrospinal Fluid Fistulae. An International Journal of Otorhinolaryngology Clinics. 9. 93-95. 10.5005/jp-journals-10003-1274.