To the Editor.—
The article "The Primary Empty Sella Syndrome: Diagnosis With Metrizamide Cisternography" by Young et al carries the strong implication that the technique described, metrizamide-enhanced computed tomography (CT), should be performed using a cervical spinal puncture to introduce the metrizamide. This is not necessary, as a lumbar puncture is sufficient, safer, and more convenient to perform. The excellent density discrimination of CT means that it is not necessary to deliver a highly concentrated bolus to the region being examined. Two of the references that the authors quote advocate the lumbar intrathecal injection of the contrast medium.1,2 Approximately 4 to 6 mL of 170 to 190 mg of iodine per milliliter is the customary dose when the lumbar route of administration is used, and this is the recommended dose in the package insert supplied by the manufacturer. Higher doses of metrizamide may be necessary if plain-film polytomography is
Jahnke RW. Diagnosis of Empty Sella Syndrome. JAMA. 1982;247(20):2779. doi:10.1001/jama.1982.03320450017013
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