MRI Back Pain Sciatica Interpretation So Variable Could Effect Patient Outcome

The MRI GOD is struck another blow – interpretation is so variable, the authors states “As a result, the authors conclude that where a patient obtains his or her MRI examination and which radiologist interprets the examination may have a direct impact on radiological diagnosis, subsequent choice of treatment, and clinical outcome.” Now that is a scary prospect.

Spine J. 2017 Apr;17(4):554-561. doi: 10.1016/j.spinee.2016.11.009.
Variability in diagnostic error rates of 10 MRI centers performing lumbar spine MRI examinations on the same patient within a 3-week period.
Herzog R, Elgort DR, Flanders AE, Moley PJ.
https://www.ncbi.nlm.nih.gov/pubmed/27867079
http://www.thespinejournalonline.com/article/S1529-9430(16)31093-2/pdf

  • 63 year old lady with l5 sciatica
  • “mild weakness in right ankle dorsiflexion 4+/5 and right great toe extension 4
    +/5, reflexes were diminished, but symmetrical bilaterally (1/4), and she had a
    positive dural tension (seated slump) sign on the right”
  • lead author considered expert in his field
  • 49 findings 1/3 appeared only appeared once in 10 reports
  • Fleiss kappa statistic value used to document agreement:
    –  0 = no better than chance
    – >0.75 excellent agreement
  • “all reported interpretive findings was 0.20±0.03, indicating poor overall agreement on interpretive findings”
  • “number of examinations reporting the presence of a disc herniation at a given
    motion segment ranged from 70% at L3–L4 to 20% at L5–S1”
  • “The number of study examinations reporting thecal sac compression due to a disc herniation ranged from 60% at L1–L2 to only one examination reporting thecal sac compression at L4–L5. Nerve root involvement due to a disc herniation was reported in 20% of the examinations at L2–L3, 40% of the examinations at L3–L4, and 30% of the examinations at L4–L5”
  • The Fleiss kappa score for agreement on the presence of a disc herniation was −
    0.02±0.23 across the five motion segments”.(POOR)
  • Fleiss kappa score for agreement on the presence of central canal stenosis was 0.17 ±0.32 across the five lumbar motion segments.(POORER YET)

 

 

 

 

 

Concluded

  • “marked variability in the reported interpretive findings and an alarmingly high number of interpretive errors in the lumbar MRI reports. “
  • “important pathologies are routinely underreported. For example,the study examinations demonstrated an average miss rate for disc herniation of 47.5%. “
  • “high false-positive rates for specific pathologies indicate that diagnostic findings, such as central canal stenosis, may be routinely overcalled”
  • overreliance on the MRI report for treatment could be disasterous

Comment – not only is serious pathology missed, I have found finding could be downplayed – ie “nerve root is only being touched by disc” – clinically this could be very important. If this was a insurance claim case, I would want my films viewed by more than one MRI site – anyone know good sites?

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