Optimal contrast concentration for CT-guided epidural steroid injections.


Journal Article

BACKGROUND AND PURPOSE: Contrast is used in CT-guided epidural steroid injections to ensure proper needle placement. Once injected, undiluted contrast often obscures the needle, hindering subsequent repositioning. The purpose of this investigation was to establish the optimal contrast dilution for CT-guided epidural steroid injections. MATERIALS AND METHODS: This investigation consisted of an initial phantom study, followed by a prospective, randomized, single-center trial assessing a range of contrast dilutions. In the phantom study, a phantom housing a chamber containing a 22-gauge needle and various dilutions of contrast was scanned, and images were evaluated for needle visibility. On the basis of these results, concentrations of 66, 100, 133, and 150 mg/mL iodine were selected for evaluation in a clinical study. Patients presenting for CT-guided epidural steroid injections were randomly assigned to a contrast dilution, and images from the procedure were evaluated by 2 readers blinded to the contrast assignment. Needle visibility was scored by use of a 5-point scale. RESULTS: In the phantom study, the needle was not visible at contrast concentrations of ≥133 mg/mL. In the clinical study, needle visibility was strongly associated with contrast concentration (P < .0001). Significant improvements in visibility were found in 66 mg/mL and 100 mg/mL compared with higher iodine concentrations; no difference was found comparing 66 mg/mL with 100 mg/mL iodine. Neither injection location (cervical versus lumbar) nor technique (interlaminar versus transforaminal) influenced visibility scores. CONCLUSIONS: For CT-guided epidural steroid injections, the optimal contrast concentration is 66-100 mg/mL iodine. Because these concentrations are not commercially available, proceduralists must dilute their contrast for such procedures.

Full Text

Duke Authors

Cited Authors

  • Kranz, PG; Abbott, M; Abbott, D; Hoang, JK

Published Date

  • January 2014

Published In

Volume / Issue

  • 35 / 1

Start / End Page

  • 191 - 195

PubMed ID

  • 23886739

Pubmed Central ID

  • 23886739

Electronic International Standard Serial Number (EISSN)

  • 1936-959X

Digital Object Identifier (DOI)

  • 10.3174/ajnr.A3626


  • eng

Conference Location

  • United States