Friday, December 12, 2008

Lumbar Spine MRI— See More, Miss Less

What do you see in this diagram?

Some see a vase while others see two faces looking at each other. They are both there.

"You see what you look for and recognize what you know". This is a hoary but true dictum in radiology.

When looking at an MRI, radiologists will detect a greater percentage of abnormalities if they are specifically looking for them. Radiologists are in part a product of their training, and carry with them biases learned during that process.

One place where this tends to show up is in lumbar spine MRI scans, which are interpreted by radiologists with significant differences in their training. It's easy to miss subtle abnormalities that are clinically relevant on this exam.

Early in their post-training career, musculoskeletal-trained radiologists tend to miss small disk herniations, while neuroradiology-trained radiologists tend to miss bone findings such as stress reactions and stress fractures.

Here is an example of a subtle right foraminal disk herniation:

Here is an example of stress-related changes in the posterior elements of L4:

Both are subtle findings, but in my experience, musculoskeletal-trained radiologists will be more likely be miss the first example, while neuroradiology-trained radiologists will be more likely to miss the second example.

If you keep this in mind, whatever your training, you will be less likely to miss either type of finding.

Vic David MD


Keshav Kulkarni said...

very good thought


dr. ratcliffe said...

I like the example about stress in the neural arch. What does the literature say about rates of progression of a spondylolisthesis and clinical outcomes lets say from a grade 0 with pars defect to a grade two with disc obliteration in a relatively short period of time.