PAIN MANAGEMENT
- 5th September 2026
SGD$695.00
MRI ARACHNOIDITIS: NORMAL CONTRAST ENHANCEMENT – WHAT TO LOOK FOR (VIDEO)
NORMAL CONTRAST ENHANCEMENT: WHAT TO LOOK FOR
Before you diagnose abnormal enhancement, you need to know what's normal
- This is part 2 of our series on the MRI appearance of arachnoiditis. If you haven't seen part 1, watch that first — it covers normal nerve root appearance and the pathogenesis of arachnoiditis.
- With suspected arachnoiditis or radiculitis, contrast is often given, so you need to know what normally enhances in the lumbar spine before you can interpret the study.
- In this video we go through the normal areas of contrast enhancement, and the areas that should not enhance, in the lumbar spine.
If you find the video helpful, please subscribe to the channel.
On a post-contrast scan, the posterior venous plexus within the vertebral body produces a normal triangular area of central enhancement. Epidural enhancement is also a normal finding — it tends to be more prominent anteriorly than posteriorly. On fat-saturated post-contrast T1 sequences, the bulk of the epidural fat itself saturates out and should not enhance; the enhancement you're seeing is from veins within the epidural fat, not the fat itself.
The dorsal nerve root ganglion normally enhances. This structure sits outside the thecal sac, within the neural foramen.
A normal venous plexus lies both anterior and posterior within the canal, most prominent over the conus and in the proximal cervical spine. It is not seen overlying the thoracic cord. On imaging this looks like thin, non-straight, non-nodular "squiggly" lines. That lack of nodularity is what helps differentiate normal venous enhancement from metastatic disease.
A single midline venous structure, the median vein, can be seen running up to the conus. If you see a single area of enhancement in the midline and can follow it back up to the conus, that's this normal vein — don't mistake it for radicular (nerve root) enhancement.
Nerve roots themselves should show no enhancement at all on a normal study. The arachnoid and pia are avascular, so normal nerve roots do not enhance. This baseline is what allows enhancement from radiculitis or inflammatory change to be correctly identified as abnormal.
- Normal enhancement is seen in the posterior vertebral body venous plexus, epidural veins (more anterior than posterior), the dorsal nerve root ganglion, and venous plexus over the conus and proximal cervical cord.
- Normal venous plexus enhancement is thin and non-nodular — nodularity should raise concern for metastatic disease instead.
- The median vein is a normal midline structure traceable to the conus — don't mistake it for radicular enhancement.
- Nerve roots should show no enhancement on a normal study, since the arachnoid and pia are avascular.
Thin, non-nodular "squiggly" lines, seen over the conus and in the proximal cervical spine. Not seen overlying the thoracic cord.
No. Nerve roots should show no enhancement normally, since the arachnoid and pia are avascular.
Trace it. A single midline venous structure, the median vein, can be followed up to the conus — if you can follow it, it's venous, not radicular.
If you wish to watch the video in language other than English, please view it on our YouTube Channel HERE
We look at all of these topics in more detail in our Guided SPINE & SIJ Imaging Mini Fellowships.
Click on the image below for more information.
- Join our WhatsApp RadEdAsia community for regular educational posts at this link: https://bit.ly/radedasiacommunity
- Get our weekly email with all our educational posts: https://bit.ly/whathappendthisweek
Our CPD & Learning Partners
OTHER POPULAR SPINE REPORTING POSTS: CLICK ON THE IMAGES BELOW
Spanish Blogs
- 5th September 2026
SGD$695.00