Final answer:
An intrathecal injection of iodinated contrast material is often performed during a CT examination of the lumbar spine to enhance visualization of the spinal column and associated structures.
Step-by-step explanation:
An intrathecal injection of iodinated contrast material is most commonly used for imaging the spine. Consequently, the correct answer to the question regarding which CT examination might involve an intrathecal injection of iodinated contrast is C. Lumbar spine.
Intrathecal contrast injection is done to enhance the visualization of the spinal column and surrounding structures during a CT scan. This method is particularly helpful when there is a need to assess the presence of certain conditions such as herniated discs, spinal tumors or other pathologies that may be affecting the spinal cord and nerve roots.
It is not typically used for imaging other areas mentioned in the other options, like the brain, the pituitary gland or for high-resolution chest scans.