What it is (overview)

A CT myelogram is a specialized imaging test that combines two steps to create detailed pictures of the spine: (1) myelography, where a contrast dye is placed into the cerebrospinal fluid (CSF) around the spinal cord, and (2) a CT scan, which uses X-rays and a computer to produce highly detailed cross-sectional images. A CT Myelogram Fluid with drain means that, in addition to injecting contrast into the spinal fluid, a clinician may temporarily use a small needle/catheter to remove (drain) a small amount of CSF to help manage CSF pressure, improve comfort, or support safe contrast distribution—depending on your clinical situation and the radiology/neurosurgery plan.

This test is designed to clearly outline the spinal cord, the fluid space around it, and the nerve roots as they exit the spine. It can show where nerves may be pinched or irritated by bone spurs, a herniated disc, narrowing of the spinal canal (spinal stenosis), scar tissue, or other abnormalities. Because the contrast highlights the CSF space, a CT myelogram can sometimes provide clearer detail than standard CT alone and can be used when MRI is not possible or does not fully explain symptoms.

What results can mean (plain language): Your report will describe whether the dye flows normally around the spinal cord and nerve roots or whether there are areas where the contrast column is narrowed, blocked, or pushed aside. Findings may suggest:

• Nerve compression (for example, from a herniated disc or bone spur), which may correlate with back pain, neck pain, sciatica, numbness, tingling, or weakness.
• Spinal stenosis (narrowing of the canal), which can cause leg pain with walking, heaviness, or balance issues.
• Abnormal pockets or leaks of CSF (in certain cases), which may relate to headaches or prior spine procedures.
• Post-surgical changes, such as scar tissue or hardware-related narrowing, especially relevant in neurosurgery planning.

When & why it's usually done

Doctors most often order a CT myelogram with CSF assessment/drainage considerations when they need a very detailed view of the spinal canal and nerve roots, particularly if symptoms suggest nerve compression and other tests have not provided enough answers. It may be recommended by a spine specialist, neurologist, or neurosurgery team.

Common reasons include:

• Persistent or severe back pain or neck pain with signs of nerve involvement (shooting pain, burning pain, numbness, tingling, or weakness).
• Radiating pain such as sciatica (leg pain) or arm pain that suggests nerve root irritation.
• Suspected spinal stenosis, especially when symptoms worsen with walking/standing and improve with sitting or bending forward.
• Suspected herniated disc or bone spurs when MRI is not possible (for example, certain implanted devices) or MRI findings do not match symptoms.
• Evaluation after spine surgery to assess nerve root compression, scar tissue, or changes around spinal hardware that can limit MRI quality.
• Pre-procedure or pre-operative planning when precise mapping of nerve roots and the spinal canal is needed.

The “with drain” component may be used in specific clinical scenarios where managing or sampling CSF is helpful for safety and image quality. Your team will explain the plan based on your history, symptoms, and prior imaging.

Common diseases related to it

• Herniated disc (cervical, thoracic, or lumbar disc herniation)
• Spinal stenosis (central canal stenosis and foraminal stenosis)
• Pinched nerve / radiculopathy (cervical or lumbar)
• Degenerative disc disease and spinal osteoarthritis (spondylosis)
• Spondylolisthesis (vertebra slipping) with nerve compression
• Spinal tumors or masses affecting the spinal canal/nerve roots
• Arachnoiditis (inflammation/scarring around nerve roots)
• Post-surgical spine complications (scar tissue, recurrent disc herniation, hardware-related narrowing)
• Cerebrospinal fluid (CSF) leak or suspected abnormal CSF flow (in select cases)

Health goals where it may help

• Finding the cause of ongoing back pain or neck pain when symptoms suggest nerve involvement
• Confirming and mapping nerve root compression to guide the best treatment plan (physical therapy, injections, or surgery)
• Supporting neurosurgery or spine procedure planning with detailed spinal canal imaging
• Evaluating why symptoms persist or return after spine surgery and guiding next steps
• Improving diagnosis when MRI is unavailable or inconclusive by using a high-detail CT myelogram
• Assessing spinal canal narrowing (spinal stenosis) severity to help set mobility and pain-control goals