Incidence and clinical significance of epidural fluid signal on spinal magnetic resonance imaging after image-guided lumbar puncture in adults.

PURPOSE

We determined the incidence of epidural fluid signal on spinal magnetic resonance imaging (MRI) after image-guided lumbar puncture (LP) in adults. We correlated those imaging findings with clinical status.

METHODS

We searched our institution's medical records from January 2013 through April 2020 to identify adult patients who underwent image-guided LP and postdural puncture MRI. We examined the incidence of epidural fluid signal intensity in adults after image-guided dural puncture, characterized its imaging features, and evaluated its associated clinical factors.

RESULTS

Of 91 patients who underwent image-guided dural puncture and subsequent spinal MRI within 7 days, 18 (20%) demonstrated epidural fluid signal on postdural puncture MRI. Univariate analysis showed that larger needle size correlated with signal presence (4/8 [50%] LP with a 20-gauge needle vs 13/82 [16%] with a 22-gauge needle, P = 0.03). The odds of observing epidural fluid signal on postdural puncture MRI decreased by 8% per 1-year increase in age (P < 0.001). Postdural puncture symptoms did not differ between those with and without epidural fluid signal intensity.

CONCLUSION

Epidural fluid signal on MRI in adults may be an incidental finding more commonly observed in younger patients after dural puncture with larger needles, without a significant correlation with symptomatology.